2016 Veterinary Spay-Neuter Guidelines: Best Practices for Medical Care

Spay-neuter programs are vital for community efforts aimed at reducing the number of unwanted and unowned cats and dogs that end up in shelters and are subsequently euthanized. These programs are designed to make spay-neuter services more accessible to specific animal populations, effectively preventing reproduction and thereby lowering birth rates and overpopulation. By focusing on underserved populations that may not have easy access to or afford spay-neuter services, these programs deliver surgical sterilization to animals that are most likely to contribute to shelter overcrowding and euthanasia rates. In the United States, this typically includes pets from low-income households and community cats, which are unowned, free-roaming cats, including both unsocialized feral cats and socialized stray cats.

Over the last decade, spay-neuter practice has rapidly developed as a significant area within clinical veterinary medicine. The range of available spay-neuter services is broad, including dedicated stand-alone practices in both stationary and mobile clinics, MASH-style operations, shelter-based services, community cat initiatives, voucher programs, and various in-clinic programs offered by private practitioners. Many veterinarians routinely perform spay-neuter surgeries on a large number of animals. Spay-neuter programs have also become integral to the clinical training of veterinary students in most veterinary colleges across the United States.

Recognizing the growing number and diversity of spay-neuter programs, and the consequent need for standardized veterinary medical care in these settings, the Association of Shelter Veterinarians (ASV) established a task force in 2006 to develop veterinary medical care guidelines for spay-neuter programs. These initial guidelines, published in 2008, offered recommendations for preoperative, anesthetic, surgical, and postoperative care. They were grounded in established principles of anesthesiology, critical care medicine, infection control, and surgical practice, derived from scientific literature and expert consensus. While primarily aimed at high-volume spay-neuter programs, the guidelines were designed to be practical and applicable across all veterinary practice environments offering spay-neuter services.

In 2014, the ASV reconvened its task force to update these guidelines. This revision process involved a thorough review of current scientific literature to incorporate the latest evidence and information into the recommendations for spay-neuter practice. This second edition of the guidelines not only updated the general guidelines for patient care and clinical procedures but also introduced new recommendations for the operational management of high-volume spay-neuter programs, addressing key aspects of management, staffing, and clinic operations. These updated guidelines, published in 2016, represent the current gold standard for veterinary medical care in spay-neuter programs.

The ASV defines High-Quality, High-Volume Spay-Neuter (HQHVSN) services as efficient surgical initiatives that meet or exceed established veterinary medical standards while providing accessible, targeted sterilization for a large number of cats and dogs to effectively reduce overpopulation and subsequent euthanasia. The ASV advocates for the continued development of HQHVSN services to ensure sufficient capacity to serve the existing populations of cats and dogs in need. While recognizing the importance of high-volume services, the ASV remains dedicated to ensuring high-quality care for each individual animal. The ASV firmly believes that the consistent application of its veterinary medical guidelines for spay-neuter programs will significantly enhance the quality of patient care, minimize risks, and improve patient outcomes in all settings where surgical sterilization is performed. It is important to note that while the ASV acknowledges nonsurgical sterilization as an emerging approach with potential value for specific populations or patients, the current guidelines are focused on surgical methods and do not include recommendations for nonsurgical sterilization techniques.

In developing these guidelines, the ASV aims to support HQHVSN programs, encourage greater participation from both veterinarians and the public, facilitate patient referral processes, provide clear guidance for veterinarians working in this practice area, encourage existing programs to adopt and adhere to these guidelines, and serve as a valuable reference for the veterinary profession, including state veterinary medical boards, other regulatory agencies, veterinary professional associations, as well as donors and funding agencies supporting spay-neuter programs. Consistent with its original objectives, the ASV hopes these 2016 guidelines will be widely adopted by the veterinary profession to maintain uniform veterinary medical care across all settings providing spay-neuter services and to promote these services as a crucial means of reducing shelter intake and euthanasia of cats and dogs.

Guidelines for Patient Care and Clinical Procedures

As in any clinical veterinary practice, meticulous attention to detail in all aspects of patient care is crucial for successful outcomes in spay-neuter programs. Providing safe and humane patient handling and housing, implementing robust infection control procedures, maintaining accurate record keeping, establishing emergency readiness protocols, and ensuring comprehensive follow-up and emergency care plans are all essential considerations for spay-neuter programs to deliver high-quality veterinary medical care.

Patient Transportation Services

Spay-neuter programs may offer patient transport services, with program staff responsible for transporting animals to and from the clinic for surgery. Recognizing the inherent risks involved in transporting live animals, ensuring safe transport conditions is paramount. Key considerations for safe patient transport include:

• Proper Confinement: Animals must be securely confined in appropriate enclosures. Enclosures should be properly secured within the transport vehicle to prevent movement during transit.
• Patient Identification: A reliable system for verifying patient identity and matching animals to their corresponding medical records is essential to prevent errors and ensure correct care.
• Environmental Control: Maintaining good air quality and comfortable temperatures within the transport vehicle is crucial. This includes appropriate heating, air conditioning, and ventilation to ensure animal well-being during all weather conditions.
• Regular Monitoring: Animals should be monitored periodically throughout the transport process. The frequency of monitoring should be determined based on the animals’ needs, the duration of transport, and prevailing environmental temperatures.

Commercial monitoring devices can be particularly useful for extended transports. Video surveillance can also facilitate patient monitoring without compromising efficiency or security. Portable, remote temperature and air-quality monitors can further enhance monitoring capabilities during transport. The specific timing and methods of monitoring are at the discretion of the program, taking into account transport limitations, available resources, and safety considerations. Strategies to minimize animal stress during transport, such as separating different species, should be implemented whenever possible.

Record Keeping

Comprehensive record-keeping procedures are essential and must comply with all applicable federal, state, and local laws and regulations. A detailed medical record should be created for each animal. This record should include:

• Physical examination findings, including any pre-existing conditions.
• Body weight, accurately measured or estimated.
• Detailed information on all drugs administered, including drug names, dosages, and routes of administration.
• The specific surgical procedure performed.
• Any abnormalities or complications encountered during the procedure or perioperatively.
• Any other pertinent information regarding the animal’s condition or treatment.

While standardized operative report forms can be helpful for efficiency, they should be flexible enough to allow for the inclusion of additional notes and details when necessary for individual patient records.

Vaccination

Vaccination is a critical component of preventative care. Ideally, vaccination should be completed prior to the day of surgery. However, perioperative vaccination is considered safe and acceptable when necessary and can effectively provide immunity. Vaccination against rabies is strongly recommended and is often mandated by state and local laws. Spay-neuter programs can significantly improve owner compliance by offering rabies vaccination services concurrently with spay-neuter procedures. However, it is ultimately the pet owner’s responsibility to ensure their pets are up-to-date with all required vaccinations in accordance with existing regulations. Vaccination procedures should adhere to the current guidelines established by the American Association of Feline Practitioners and the American Animal Hospital Association.

Patient Handling and Housing

Implementing proactive strategies to minimize patient stress and fear while maximizing patient comfort is fundamental to patient care in all clinical settings, including spay-neuter programs. Safe, low-stress handling techniques are paramount for animal health and well-being. Dogs that are not comfortable walking on a leash should be physically carried when feasible. Cats exhibiting signs of fractious or feral behavior should be transported and housed in covered traps or other appropriate transport carriers.

Procedures for temporary housing of patients both before and after surgery must be designed to prioritize safety and comfort. Key recommendations for temporary housing include:

• Individual Identification: A clear and reliable system for identifying individual animals is essential to prevent mix-ups and ensure proper care.
• Environmental Control: Housing areas must provide adequate temperature control and ventilation to maintain patient comfort and minimize stress.
• Species Separation: To the greatest extent possible, different species (e.g., cats and dogs) should be housed separately to reduce stress and potential disease transmission.
• Stress Reduction: Minimize noise and other environmental stressors such as excessive barking, loud music, and unnecessary foot traffic to create a calm and restful environment.
• Hygiene: Housing areas must be thoroughly cleaned and disinfected between patients to prevent disease spread.
• Appropriate Enclosures: Tractable adult animals can be housed in individual cages, runs, or portable crates/pet carriers that allow for good visibility and adequate space for the animal to stand, turn around, and rest comfortably, ensuring safety during sedation and anesthesia recovery.
• Social Housing (Conditional): At the discretion of the attending veterinarian, littermates or animals from the same household may be housed together, or with their mothers, prior to sedation or anesthesia, which can be beneficial for stress reduction in some cases.
• Special Housing for Intractable/Feral Animals: Intractable or feral animals should be housed in traps or other secure enclosures that allow for anesthetic administration without requiring extensive handling, minimizing stress for the animal and maximizing safety for handlers.
• Delayed Removal from Traps: Intractable or feral animals should only be removed from their traps or enclosures after they have been adequately sedated to ensure safety for both the animal and staff.

When handling and moving sedated and anesthetized patients, special care is required. The head and neck should be properly supported and kept in a straight alignment with the body to maintain an open airway. The patient’s torso should be continuously supported to avoid stressing joints. Patient comfort should be continuously monitored by ensuring proper thermoregulation and managing any signs of stress or pain.

Infectious Disease Control Procedures

Minimizing the risk of infectious disease exposure for patients undergoing spay-neuter surgery is a top priority. From the moment of initial patient contact through discharge, patients should be closely monitored for any signs of infectious disease. If signs of illness are observed, the patient must be immediately isolated from other animals for the duration of their stay at the clinic. Standard protocols for cleaning, disinfection, and containment of potentially infectious diseases, as practiced in any veterinary setting, should be rigorously established and consistently followed.

Specific biosecurity measures for spay-neuter programs should include:

• Equipment Disinfection: Between each patient, all equipment that comes into direct contact with patients (e.g., examination tables, endotracheal tubes, masks, laryngoscope blades, pulse oximeter probes, esophageal stethoscopes, and thermometers) must be thoroughly cleaned and disinfected using agents known to be effective against common veterinary pathogens, including resistant unenveloped viruses like parvovirus and calicivirus.
• Anesthetic Equipment Maintenance: Anesthetic equipment should be regularly inspected, cleaned, and maintained on a schedule that is appropriate for the clinic’s surgery volume.
• Hand Hygiene: Staff must wash or sanitize their hands thoroughly, or change gloves, between handling individual patients and litters to prevent cross-contamination.
• Surgical Scheduling for Potentially Contagious Animals: If animals exhibiting clinical signs consistent with contagious infectious diseases are deemed appropriate surgical candidates, they should be scheduled for surgery after all apparently healthy animals have undergone their procedures to minimize the risk of disease transmission within the clinic.

Spay-neuter programs often admit patients from diverse sources on the same day, such as animals from different shelters or rescue organizations. Strategies to limit cross-contamination between patients from different sources are crucial. For example, dedicating separate sets of equipment for use with patients from a common source can be effective. In this scenario, each equipment set would be used on a rotating basis for patients from its designated source. When logistically feasible, housing animals in cohorts based on their source or scheduling patients from different sources on different days can also significantly aid in infectious disease control.

Preparation for Emergencies

Emergency readiness protocols are absolutely essential in any surgical setting. A qualified veterinarian must be present and immediately available to triage and manage any complications that may arise during anesthesia, surgery, or the immediate postoperative period. The veterinarian should remain on the clinic premises until all patients are fully extubated, in sternal recumbency, and responsive. Clinic staffing levels must be adequate and commensurate with the patient volume to ensure high-quality veterinary medical care is provided in accordance with these guidelines.

All clinic staff and volunteers must be thoroughly trained to recognize emergency situations. Designated clinic staff members trained in cardiopulmonary resuscitation (CPR) should be readily available to provide life support if necessary. Staff training should include regular drills or rounds to review the identification of respiratory or cardiovascular arrest versus simple depression, and to practice the fundamentals of CPR. Rounds can also incorporate equipment inspections, review of emergency record keeping procedures, discussions of difficult cases, and morbidity-mortality reviews.

Standard emergency equipment, including a reliable oxygen source and means of ventilation (e.g., an anesthesia machine or manual resuscitator), as well as a complete emergency drug kit with reversal agents that are within their expiration dates, must be readily accessible and in ample supply at all times. Additionally, easily accessible emergency drug charts, detailing drug dosages based on body weight and available drug concentrations, should be available to facilitate rapid and accurate dose preparation in emergency situations. Several resources provide examples of effective emergency drug charts.

Follow-up and Emergency Care

Spay-neuter programs must have established policies and procedures for managing postoperative complications and emergencies that may occur after a patient has been discharged from the clinic. Ideally, the program should be equipped to perform its own re-examinations and follow-up care. For MASH-style and mobile clinic programs, pre-arranged contingencies for emergency veterinary care at a nearby facility are crucial. In the unfortunate event of a patient death while in the clinic’s care, the owner, caregiver, or authorized agent must be notified immediately, and permission to perform a necropsy to determine the cause of death should be requested. Patient discharge instructions provided to owners or caregivers must clearly state that the clinic should be contacted regarding any postoperative concerns or problems that may arise. If a patient dies after discharge, a necropsy should be performed if possible to determine the cause of death. The necropsy can be performed by an independent diagnostic laboratory or by the clinic veterinarian, with appropriate documentation.

Guidelines for Preoperative Care

Meticulous attention to preoperative procedures and considerations is essential for building confidence in spay-neuter programs. Addressing client expectations and concerns, carefully selecting appropriate patients, and prioritizing patient safety collectively reduce stress for clients, patients, and staff. These efforts contribute to higher quality patient care, minimize the risk of legal liability, and positively promote the program’s reputation.

Patient Selection

Patient selection criteria may vary depending on factors such as clinic staffing levels, anesthetic capabilities, geographic location, staff technical training, and economic considerations. Ultimately, a veterinarian must make the final decision regarding the acceptance of any patient for surgery. This decision should be based on a thorough review of the animal’s history, physical examination findings, and the program’s surgical schedule. The surgeon should exercise professional judgment in determining minimum and maximum patient age and body weight, considering the available staff expertise and the necessary equipment to provide appropriate care for patients of varying sizes and ages. For owned pets, scheduling surgery at 4 months of age or older is generally recommended to optimize the development of immunity following timely vaccinations. Neutering before sexual maturity is strongly recommended to prevent unintended litters, which are common when surgery is delayed. In situations involving pediatric and adult animals intended for adoption, neutering is best performed prior to adoption, as early as 6 weeks of age, to ensure compliance with spay-neuter agreements. Pre-adoption neutering also increases the likelihood that adopted animals will remain in their new homes, as being sexually intact is a leading risk factor for owner relinquishment of cats and dogs.

Veterinarians must carefully weigh the risks and benefits of neutering patients with mild infectious or noninfectious medical conditions, such as upper respiratory tract infections, parasite infestations, or subclinical heartworm infections. While some conditions may theoretically increase the risk of anesthetic complications or the transmission of infectious diseases to other animals, the benefits of neutering often outweigh these risks in the context of a spay-neuter program. Because the opportunity to neuter a particular animal may not arise again, the benefits of neutering when the opportunity is available generally outweigh the potential risks associated with these mild medical conditions. For animals that are pregnant, lactating, in estrus, or have pyometra, the task force’s experience indicates that neutering can be performed safely. However, additional medical care should be provided as indicated by the patient’s specific condition.

Client Communication

Obtaining a thorough patient history is crucial. This history should include:

• Current health status and any current clinical signs of illness.
• All current medications and supplements the animal is receiving.
• History of previous vaccinations.
• Pre-existing medical conditions.
• Any history of adverse reactions to medications or anesthesia.

In addition, clients must be given clear instructions on appropriately withholding food from their animals prior to surgery. Clients must be fully informed of the surgical and anesthetic risks involved and must provide informed consent for the anticipated procedures.

Prior to the administration of anesthesia, consent forms must be signed by clients or their legally authorized agents (i.e., individuals of legal age who are authorized to make medical decisions for the patient). While the specific content of consent forms may vary between programs, important topics to consider including are:

• Client confirmation of the patient’s apparent good health, to the best of their knowledge.
• Acknowledgement of the risk of infectious disease exposure, including a higher risk if the animal has not been previously vaccinated.
• Acknowledgement of the inherent risks of anesthesia and surgery, including the risk of death, although rare.
• Acknowledgement of the risks associated with patient transport, if applicable to the program.
• Notification of any permanent identification procedures that may be performed, such as tattooing, ear tipping, or microchipping.
• Authorization for the spay-neuter surgery and any other necessary procedures deemed appropriate by the veterinarian.
• A clear recommendation that ongoing health care for the pet should be provided by a full-service veterinary clinic.
• Complete client contact information, including emergency telephone numbers.
• A clear description of any fees associated with the services.

Withholding Food

Food should be withheld from all animals for an appropriate period before surgery to reduce the risk of vomiting and aspiration during anesthesia. However, withholding water is neither necessary nor recommended, as dehydration can be detrimental. For pediatric animals (6-16 weeks old), a small meal should be offered 2-4 hours before surgery, and food should not be withheld for more than 4 hours prior to surgery due to their limited glycogen stores and higher metabolic rate. For juvenile and adult animals (over 16 weeks old), food should be withheld for a minimum of 4 hours. While overnight fasting is acceptable, withholding food for more than 6 hours is generally not necessary and may be counterproductive. Exceptions to these minimum fasting periods may be made for feral cats in traps due to safety concerns associated with removing uneaten bait from traps.

Physical Examination

A thorough physical examination should be performed on every patient by a veterinarian or a supervised veterinary student to determine surgical candidacy. Ideally, the physical examination should be performed before the animal is anesthetized. However, anxiety, aggression, or feral behavior may make a complete examination prior to sedation or anesthesia induction challenging or impossible. Ultimately, the timing of the physical examination (before or after premedication or anesthesia) should be at the discretion of the attending veterinarian, prioritizing patient and staff safety.

The physical examination should include:

• Verification of the animal’s sex.
• Verification of reproductive status (sexually intact versus neutered), if possible, by checking for ventral abdominal tattoos, surgically tipped ears, or other indicators of prior sterilization.
• Microchip scanning to check for pre-existing identification.

Measuring body temperature is optional and at the discretion of the attending veterinarian. Similarly, pre-anesthetic diagnostic testing is not routinely required but may be performed at the veterinarian’s discretion based on individual patient factors. Body weight should be determined as close to the time of surgery as practically possible. If weighing an individual animal is not feasible (e.g., intractable or feral animals), body weight should be estimated as accurately as possible to ensure appropriate drug dosages.

Guidelines for Anesthetic Procedures

Spay-neuter programs require anesthetic protocols that are both safe and efficient, enabling the sterilization of a large number of animals within a limited timeframe. Carefully designed anesthetic protocols, including drug selection, perioperative care, patient monitoring, and overall technique, are essential. Balanced anesthesia, which involves administering a combination of drugs to safely achieve effective analgesia, unconsciousness, muscle relaxation, and immobility without compromising patient well-being, is a key principle.

Perioperative Thermoregulation

Hypothermia is a common and potentially serious perioperative complication in any surgical setting. Patients undergoing spay-neuter procedures, particularly in high-volume settings, are at considerable risk of developing hypothermia. Therefore, proactive measures to maintain normal body temperature should be implemented from the time of patient admission through to discharge.

Prior to premedication and anesthesia induction, the ambient temperature and humidity in patient housing areas should be carefully controlled to ensure animal comfort. Drafts should be avoided, and animals should be kept dry. Body heat conservation can be enhanced by providing various bedding materials such as paper, towels, or blankets. The thermoneutral zone for cats and dogs can vary depending on individual factors. The recommended ambient temperature range for housing cats and dogs is generally between 18° and 28°C (64° and 84°F), with a typical setting in the low to mid 70s Fahrenheit. However, the ideal temperature setting and the amount of bedding material should be tailored to the specific needs of individual animals. Animals recovering from anesthesia often require warmer environmental temperatures, and sick, frail, and pediatric patients may need even warmer temperatures than healthy adult animals. The location of the animal within the clinic should also be considered, as there can be temperature variations between floor level and elevated enclosures. Supplemental heat sources should be used when necessary, but care must be taken to prevent hyperthermia and thermal burns. Research in human medicine has shown that maintaining warmer environmental temperatures in preoperative, surgical, and recovery areas helps patients stay warmer.

Prewarming patients before administering premedications and anesthetic agents can be an effective strategy to reduce perioperative hypothermia. Contact with cold surfaces, especially after premedications have been given, can significantly lower a patient’s body temperature, which can be difficult to raise during surgery. Therefore, contact with cold surfaces should be minimized as much as possible. This can be achieved by placing a small blanket, towel, fleece pad, or paper underneath each patient immediately after anesthetic induction and keeping these materials under the patient as they are moved through different areas of the clinic (e.g., preparation, surgery, and recovery). This technique also enhances biosecurity by providing a physical barrier, reducing the risk of cross-contamination between patients.

During patient preparation for surgery, excessive clipping or wetting of hair around the surgical site should be avoided. Warmed preparation solutions should be used to minimize heat loss and help maintain the patient’s body temperature. Using low oxygen flow rates with rebreathing anesthetic circuits can also help conserve body heat. However, low flow rates are not appropriate for non-rebreathing circuits. Surgery should begin as soon as possible after preparation is completed to minimize further heat loss.

Intraoperative heat loss can be further minimized by limiting the exposure of body cavities, increasing the ambient temperature in the operating room, and providing additional insulation for patients, such as wrapping extremities in bubble wrap, newspaper, or polystyrene. Active patient warming methods can be employed using heated surgical tables, semiconductive polymer fabric heating blankets, circulating warm water blankets, and warm air blankets. Creating a warm microenvironment for the patient can be achieved using carefully protected warmed containers. Conversely, unprotected contact with or careless use of blow dryers, heat lamps, drying cages, electric heating pads, and hot water or heated materials must be strictly avoided to prevent thermal injury.

Anesthesia Equipment

The anesthesia equipment used in spay-neuter programs is generally the same as that used in any standard veterinary practice. However, when equipment is used in a high-volume setting, special attention should be given to its use and maintenance to optimize patient safety. As in any surgical setting, all anesthesia equipment, including endotracheal tubes, laryngoscopes, anesthesia machines, and monitors, should be thoroughly prepared and checked daily before use. Machine safety checklists are readily available from various sources.

Anesthesia equipment in high-volume programs experiences a high level of use, often by multiple personnel. Therefore, all programs should develop and implement a regular maintenance schedule for all equipment. The frequency of maintenance should be commensurate with the level of use; heavily used equipment in high-volume programs will require more frequent servicing. Anesthesia machines and monitors should be maintained according to manufacturers’ recommendations, either through regular in-house procedures or by outsourcing to reputable equipment and vaporizer service companies.

Carbon dioxide absorbents in anesthesia machines should be checked and changed regularly. Higher patient volumes necessitate more frequent changes and cleaning of absorbent canisters. A waste gas scavenging system should always be used to minimize personnel exposure to anesthetic gases. Both active and passive scavenging systems are acceptable. For personnel safety, particularly in high-volume settings where surgery is performed for many hours daily on a regular basis, the use of charcoal canisters for waste gas scavenging is discouraged. Charcoal canisters are effective for only short periods of time, typically just a few hours. When canisters are used, they must be carefully monitored, weighed regularly, and discarded at the end of their effective service life.

Oxygen Supplementation and Ventilation Strategies

While not mandatory for all patients, oxygen supplementation, both before and after surgery, is strongly recommended for high-risk patients. These include brachycephalic breeds, frail or ill animals, and those in advanced stages of pregnancy. The capability to provide oxygen supplementation when medically indicated is a fundamental requirement for all spay-neuter programs. Appropriate oxygen flow rates for mask oxygen delivery will vary depending on the patient’s size, the breathing system being used, and the degree of mask seal. Oxygen flow rates for oxygen delivered through endotracheal tubes should be adequate and specific to the rebreathing or non-rebreathing circuits in use.

Ventilation can be supported in anesthetized patients by connecting the anesthesia machine to a rebreathing circuit with a functioning carbon dioxide absorbent or to a non-rebreathing circuit with appropriate oxygen flow rates. Alternatively, a manual resuscitator connected to an oxygen source with a regulator can be used for both oxygen supplementation and ventilation. Ventilation can be compromised if carbon dioxide absorbents are depleted or exhausted. Therefore, vigilance in monitoring the adequacy of carbon dioxide absorbent is essential. Ventilation is also compromised when inappropriately low oxygen flow rates are used with non-rebreathing circuits. Capnography is a valuable monitoring tool for assessing the adequacy of ventilation, carbon dioxide absorbent function (or other causes of rebreathing), and the patient’s circulatory status.

Airway Management

For cats, dogs, and rabbits, airway management options include facemasks and endotracheal tubes. Commercially available supraglottic airway devices also offer an alternative. When airway management devices are used, they must be properly sized and carefully secured in place. Tape or ties made from plastic tubing, gauze, or other suitable materials are acceptable for securing these devices. When using a mask in patients with nasal congestion, ensure the mouth remains open to allow for breathing.

Endotracheal intubation provides a secure and patent artificial airway but does not necessarily require the use of oxygen or inhalant anesthetics. Traditionally, intubation with a cuffed endotracheal tube has been considered the gold standard for airway protection in anesthetized patients. However, intubation requires specific training, practice, time, patience, and achieving an appropriate depth of anesthesia. It can potentially compromise patient care if not performed skillfully, carefully, and efficiently. Improper or traumatic endotracheal tube placement can increase patient risk, particularly in cats. A large-scale epidemiological study of risk factors associated with anesthetic complications documented that intubation in cats is not a benign procedure and can result in iatrogenic trauma. The study also showed a significant increase in the risk of adverse events, including death, associated with intubation in cats undergoing short anesthesia durations.

The benefits of intubation must be carefully weighed against the potential risks for all patients undergoing spay-neuter surgery. When balanced anesthesia is achieved using injectable drug protocols, routine intubation of all patients undergoing spay-neuter surgery is not always necessary. However, the ability to perform intubation when medically indicated, including rapid intubation in emergency situations, is a crucial requirement for all spay-neuter programs. If intubation is performed as a standard component of an anesthetic protocol, it is critical to have an anesthesia team with the necessary skills for this procedure. The anesthetist must always verify correct endotracheal tube placement, either by direct visualization or by using a capnograph. Patients who particularly benefit from intubation include all brachycephalic patients, overweight or obese patients, animals in advanced pregnancy, patients with pre-existing severe upper respiratory disease, and patients undergoing procedures anticipated to last longer than 30 minutes.

Fluid Therapy

Routine fluid administration is not always necessary for elective surgical procedures, especially when surgery times are short and uncomplicated. However, fluid supplementation is recommended for high-risk patients, such as those undergoing ovariohysterectomy in advanced pregnancy or with pyometra, and when significant blood loss or prolonged surgery times are expected or encountered. The ability to provide intravenous (IV) fluid administration when medically indicated is a requirement for all spay-neuter programs. For routine fluid support in many patients, subcutaneous (SC) fluid administration is often adequate. When SC fluids are used, administration during the immediate postoperative period is recommended as it avoids the stress and potential pain associated with SC injections in awake patients. For patients at higher risk of clinically significant hypothermia (e.g., pediatric, small, frail, or ill patients), warming fluids to body temperature prior to administration, or warming the fluid line during administration, should be considered. Fluid administration can enhance recovery from anesthesia. When fluids are used, they should be administered in accordance with current veterinary medical guidelines for fluid therapy.

Monitoring

Continuous and careful monitoring of each individual patient is essential, starting from the administration of premedications or anesthetic agents and continuing throughout the recovery period. Patient monitoring is critical for ensuring safety and maintaining an appropriate and safe plane of anesthesia. Recognizing changes in vital parameters is essential for accurate assessment. The most reliable way to ensure continuous patient assessment and safety during anesthesia is vigilant, hands-on observation by trained staff. Generally, monitoring multiple variables is necessary to accurately assess the depth of anesthesia. Relying on a single variable alone can lead to either an inadequate plane of anesthesia or, conversely, an excessive depth, increasing the risk of complications, including death.

Depending on individual circumstances, monitoring should include assessment of various combinations of vital parameters. In accordance with current veterinary anesthesia monitoring guidelines, using objective monitoring methods is also necessary. These options include, but are not limited to, pulse detection (palpation or Doppler ultrasound), auscultation of the heartbeat, pulse oximetry, capnography, and blood pressure monitoring. Pulse oximetry is highly encouraged as it provides an objective auditory and visual means of determining pulse presence, pulse rate, and oxygenation adequacy. Pulse oximetry monitors have been shown to reduce the risk of anesthetic death in cats. Pulse oximetry is preferred over electrocardiography (ECG), which may not accurately assess heart rate because it reflects electrical activity rather than mechanical activity and does not provide any indication of oxygenation status.

While various types of monitoring equipment can enhance patient monitoring, their use should not replace continuous monitoring by trained personnel. The specific timeframes for monitoring, the parameters monitored, and the methods of recording vital parameters are at the attending veterinarian’s discretion and should be appropriate for each program, patient, and procedure.

Pulse Quality, Rate, and Rhythm: Directly monitoring pulse quality is crucial. The pulse can be assessed by manual palpation of the radial, dorsal metatarsal, femoral, lingual, facial, or carotid arteries.

Respiratory Rate and Pattern: Monitoring respiratory rate and pattern is particularly valuable for early detection of anesthetic problems. Respiratory rate should be assessed by observing chest movements or by auscultating the lungs with a stethoscope. Direct monitoring is preferred over respiratory or apnea monitors, which can sometimes sense false flow impedance changes due to abdominal manipulation during surgery (false diaphragmatic motions) rather than actual effective respiration. Similarly, solely relying on rebreathing bag movement to monitor respiration can lead to inaccurate assessments.

Jaw Tone: A moderately relaxed jaw tone typically indicates a surgical plane of anesthesia in most patients. A very lax jaw tone may suggest excessive anesthetic depth, while a tense jaw tone may indicate an inadequate plane of anesthesia or be related to the use of dissociative anesthetic agents. It is important to note that pediatric puppies normally lack mandibular tone, so jaw tone should not be used to assess anesthetic depth in these young patients.

Eye Position and Pupil Size: Generally, a central eye position with dilated pupils suggests a potentially dangerously deep plane of anesthesia. However, in cats and dogs anesthetized with high doses of dissociative anesthetic agents, a central eye position and pupillary dilation can occur without indicating complications. Moderate ventral rotation of the eyes often indicates an adequate surgical plane of anesthesia in most species but is dependent on the specific drug combination used for anesthesia.

Palpebral Reflex: A diminished palpebral reflex is a sign of increasing anesthetic depth. However, this reflex may be absent in animals anesthetized using injectable anesthetic protocols, especially those including dissociative agents.

Mucous Membrane Color and Capillary Refill Time (CRT): Mucous membrane color and CRT are subjective assessments of perfusion but should not be used as the sole indicators of circulatory adequacy. Many factors, including age, body temperature, and hematocrit, can influence these parameters. Pallor is a non-specific clinical finding; pale mucous membranes can indicate peripheral vasoconstriction (often seen with α2-adrenoceptor agonists), hypothermia, anemia, or hypoxemia. Notably, a normal CRT can sometimes be observed even following cardiac arrest.

Anesthetic Protocol

Selecting appropriate anesthetic protocols for spay-neuter programs depends on various factors, including the number and type of patients, the skill and efficiency of available technical assistance, the timing and competence in surgical and anesthetic techniques, and drug availability. Four key criteria guide the selection of the safest, most humane, and most time- and cost-effective anesthetic protocols: provision of analgesia, stress reduction or anxiolysis, immobility and muscle relaxation, and safe, controlled, reversible central nervous system (CNS) depression resulting in unconsciousness. Numerous cost-effective protocols combining multiple anesthetic and analgesic drugs, including both injectable and inhalant agents, are available for achieving balanced anesthesia in pediatric and adult patients. A comprehensive list of all effective and appropriate anesthetic and analgesic drugs is beyond the scope of these guidelines. Extralabel use of many anesthetic and analgesic agents is common and appropriate practice in veterinary medicine.

Accurate Dosing of Anesthetic Agents

Given the high-volume nature of many spay-neuter programs, there might be a temptation to use predetermined or standardized drug doses (a “one-size-fits-all” approach). However, this approach fails to account for individual patient variations in temperament, weight, and health status, and can lead to inappropriate dosing, including overdosing smaller patients and underdosing larger ones. For example, using a standard dose of dexmedetomidine for all cats, regardless of size, is not recommended. Similarly, administering drug volumes that only fill the needle hub should be avoided as it is inaccurate and prone to error. Conversely, using weight bands for drug doses (e.g., X μg of drug for patients weighing 1-2 kg and Y μg for patients weighing 2-4 kg) can be an acceptable way to streamline dose preparation while still accounting for weight differences. Furthermore, using drug dose charts that express doses as a function of body weight can help prevent calculation errors. However, when using dose charts, caution should be exercised for patient weights at the extremes of the range (very small and very large patients). In these cases, dosing based on body surface area or metabolic scaling is recommended for improved accuracy. In situations where accurate body weight cannot be obtained prior to drug administration, such as in programs serving community cats, safety is enhanced by using reversible agents, avoiding drugs that cause marked cardiorespiratory depression, and estimating body weight as accurately as possible.

Careful attention to the labeled concentration of each drug is also essential for accurate dosing. Drug concentrations should be selected to result in appropriate volumes for the patients typically seen in the program. If commercially available drug concentrations do not facilitate accurate dosing, stock concentrations should be diluted as needed for individual drugs. For example, an anesthetic drug commercially available as a 10 mg/mL solution could be diluted to 1 mg/mL to aid in preparing small doses for pediatric patients. Finally, using compounded drugs can facilitate accurate patient dosing. However, clinics must ensure full compliance with all federal, state, and local laws and regulations related to drug compounding.

Administration of Analgesics and Anxiolytics

Analgesic agents are essential for all patients undergoing neutering and should be administered prior to the initial surgical incision to preemptively manage pain. Acceptable analgesic choices include opioids, α2-adrenoreceptor agonists, non-steroidal anti-inflammatory drugs (NSAIDs), and local anesthetics. Multimodal analgesia, which involves using multiple analgesic agents with different pharmacological mechanisms to control pain synergistically, is highly recommended whenever possible. This approach often provides superior pain control with fewer adverse effects compared to using single agents.

The use and timing of NSAID administration should be based on the specific drug and individual patient factors. Patient hydration status and the presence of pre-existing hepatic, renal, or gastrointestinal disease or clotting abnormalities should be carefully considered. Administering NSAIDs to patients who are clinically or subclinically dehydrated should be avoided due to the increased risk of adverse effects, including nephrotoxicity.

Agents for stress reduction and anxiolysis include minor and major tranquilizers (e.g., acepromazine, midazolam, and diazepam) and α2-adrenoreceptor agonists. These can be effectively combined with analgesics for premedication.

Total Intramuscular (IM) Anesthesia

Administering a single IM injection that combines sedative, analgesic, and anesthetic induction agents can reduce patient pain and stress compared to multiple injections. Combining premedications and anesthetic induction agents into a single injection is a valuable technique for many spay-neuter programs, particularly for less tractable animals. Recommended combinations for single injections often include α2-adrenoreceptor agonists, opioids, and dissociative drugs, as these combinations, when administered in appropriate doses, provide patients with multimodal analgesia and balanced anesthesia.

Anticholinergic Agents

Anticholinergic agents, such as atropine or glycopyrrolate, may or may not be routinely administered as part of an anesthetic protocol. However, they should be readily available in all spay-neuter clinics for individual patient needs and emergency use. Anticholinergic agents are not the appropriate treatment for bradycardia induced by α2-adrenoreceptor agonists because they can increase cardiac workload. In the rare instances when α2-adrenoceptor agonist-associated bradycardia results in patient compromise, reversal or partial reversal of the α2-adrenoceptor agonist is the preferred approach to restore heart rate.

Induction and Maintenance of Anesthesia with Inhalant Anesthetics

While there may be situations where mask administration of inhalant anesthetics is necessary in spay-neuter programs, routine mask induction and maintenance should be minimized. Furthermore, chamber induction using inhalant anesthetics should be strictly avoided.

Mask Induction: Mask induction involves inducing general anesthesia by delivering inhalant anesthetics via a facemask. Routine mask induction is not recommended and should be avoided. Loss of consciousness is poorly controlled with mask induction, and patients experience a relatively higher degree of stress compared to injectable induction methods. Additionally, proper mask induction requires high oxygen flow rates, which can lead to substantial environmental contamination with waste anesthetic gases, especially problematic in confined spaces. When inhalant anesthetics are used as sole agents for induction, high concentrations are required, which can potentially be harmful to patients. In dogs, mask induction has been associated with a higher risk of anesthesia-related death. Patients are more amenable to mask induction if they are adequately premedicated with injectable agents prior to inhalant anesthesia administration.

Chamber Induction: Chamber induction involves inducing general anesthesia by delivering inhalant anesthetics within a chamber (an enclosure surrounding the animal or its head and face). Given the availability of multiple safe and effective alternative anesthetic protocols, chamber induction in high-volume spay-neuter settings is rarely justified or necessary. However, in rare circumstances (e.g., failure of an injectable protocol, lack of IV access, or extremely fractious animals that cannot be safely injected), chamber induction, particularly with rapid-acting inhalants like sevoflurane, may be considered. Clinicians should be aware that chamber induction produces the highest levels of waste anesthetic gas exposure.

Mask Maintenance: Mask maintenance or supplementation refers to continuing general anesthesia for a period by delivering inhalant anesthetics via a facemask. Mask maintenance may be used on an as-needed basis for some patients in spay-neuter programs. For short procedures in cats, it may be safer than endotracheal intubation. Potential risks associated with mask maintenance include bronchial irritation, aspiration of gastric contents, and environmental contamination with waste anesthetic gases. Fortunately, commonly used modern anesthetic gases (isoflurane and sevoflurane) cause minimal bronchial irritation compared to older agents. If mask supplementation becomes frequent or routine, consider altering the anesthetic protocol to reduce the need. This could involve enhancing initial sedation and analgesia or administering additional analgesics, such as low doses of an opioid, ketamine, or an α2-adrenoreceptor agonist, to maintain an adequate surgical plane of anesthesia.

Mitigating Waste Anesthetic Gas Exposure

Anesthetic machines can contribute to environmental pollution from waste anesthetic gases. In addition to performing daily leak tests and using properly functioning scavenging systems, several other measures should be routinely implemented to minimize waste gas release:

• Minimize airway leaks by using appropriately sized endotracheal tubes with proper cuff inflation.
• Before disconnecting patients from the breathing system after surgery, eliminate as much residual gas as possible. Turn off the vaporizer and allow patients to breathe oxygen, ideally for 5 minutes, prior to disconnection.
• Before disconnecting patients, empty the rebreathing bag after turning off the vaporizer. If using a circle system, increase the oxygen flow rate to 2-3 times the maintenance rate to help flush the system.
• Turn off vaporizers and flow meters completely when patients are disconnected from the anesthesia machine.
• Use caution when filling vaporizers. Ensure the room is well-ventilated, and minimize the number of staff present during filling.

High-Risk Patients

Attending veterinarians may identify certain patients as being at high risk for anesthetic or surgical complications based on their history and physical examination findings. These high-risk patients can include brachycephalic breeds, geriatric animals, and patients with significant pre-existing medical conditions. At the veterinarian’s discretion, alternative anesthetic protocols may be indicated for these patients. Anesthetic protocols for high-risk patients should minimize the use of agents that cause marked cardiorespiratory depression and might include reversible agents, oxygen and fluid supplementation, and endotracheal intubation if airway patency is questionable. The veterinarian or a designated and supervised member of the care team should communicate specifically with the owner, caregiver, or authorized agent of high-risk patients about the patient’s increased anesthetic risk.

Guidelines for Surgical Care

Implementing spay-neuter surgical practices based on established principles of infection control, surgical asepsis, and refined surgical technique is crucial for maximizing surgical success and minimizing the risk of complications. Efficient surgical practices also reduce surgery times, which can improve patient recovery. Spay-neuter programs can establish and use standard operating procedures for surgical techniques, tailoring these techniques to individual patient needs at the surgeon’s discretion. The practices described in these guidelines represent attainable standards for spay-neuter programs regardless of location, facility, or program type.

Operating Area Environment

The operating area should be a dedicated room or space where anesthesia, surgery, and immediate postoperative recovery can be safely performed. The necessary equipment for anesthesia and patient monitoring must be present and readily accessible. Traffic within the operating area should be limited to essential personnel only. Regular sanitation procedures should be implemented and consistently followed.

Surgical Pack Preparation

Separate sterile surgical instrument packs are required for each patient to prevent cross-contamination and infection. Instruments must be thoroughly cleaned prior to sterilization. Sterilization of surgical packs can be achieved using steam, gas, or plasma sterilization methods. The sterilization date and the name of the person responsible for sterilization should be clearly identifiable on each pack. A sterility indicator should be placed both inside and outside each surgical pack. While sterility indicators do not guarantee pack sterility, they aid in detecting procedural errors and equipment malfunctions and allow for quick differentiation between processed and unprocessed packs. A variety of materials, including reusable and disposable materials, are acceptable for the outer wrap of surgical packs. The outer wrap material must provide a minimum microbial barrier equivalent to dry 270-thread count pima cotton. Additionally, the wrap material and pack storage conditions must ensure maintenance of sterility for the longest anticipated pack turnover interval.

Patient Preparation

Several key aspects should be considered during patient preparation for surgery:

Urinary Bladder: Emptying the urinary bladder prior to abdominal surgical procedures simplifies surgical manipulation and increases postoperative comfort for both male and female patients. If bladder expression is performed, it should be done with care. If excessive pressure is needed to express the bladder preoperatively, and bladder expression is deemed necessary, urethral patency should be evaluated. Expression should be delayed until a deeper plane of anesthesia is achieved, or intraoperative examination and surgical expression are possible.

Skin Preparation: Skin preparation should be performed in a way that preserves skin integrity. The prepared area must be sufficiently large to prevent inadvertent contamination of the sterile surgical field and to accommodate extension of the incision if needed. After hair removal, the entire skin area should be meticulously prepared using an appropriate surgical scrub agent, following accepted patient preparation practices.

Patient Positioning: Ties, V-trays, adjustable surgery tables, or other positioning devices may be used to position patients for surgery. The patient’s body can be maintained in a level or tilted position, with the head and neck kept in straight alignment. Care must be taken to position the patient in a way that avoids compression of the thorax or diaphragm and ensures optimal airway patency. The patient’s limbs may be secured in place or left unconstrained at the surgeon’s discretion. Hyperextension of the limbs should be avoided, as it can restrict chest excursion, compromising respiration, or increase tension on suspensory ligaments, potentially complicating ovary exposure and increasing postoperative discomfort. For abdominal procedures, the thoracic limbs may be positioned cranially (resting alongside the head or neck) or caudally (resting alongside the lateral aspects of the thorax). If ties are used to secure limbs, care must be taken to avoid any constriction of the extremities.

Patient Draping: Sterile patient draping is mandatory for all abdominal procedures and for castration in adult dogs. The surgical drape should be of adequate size to effectively prevent contamination of the sterile field. Drape material must be resistant to fluid and microorganism penetration under normal operating conditions. The barrier function of reusable drapes can degrade after repeated launderings. Therefore, processing of reusable drapes should strictly adhere to published guidelines for laundering, autoclaving, and recommended service life. For routine castration of cats and puppies, the use of a clean or sterile drape is at the surgeon’s discretion. However, if a drape is not used, extra care must be taken to prevent contamination during the procedure.

Surgeon Preparation

The following aspects are crucial for proper surgeon preparation:

Surgical Attire: The surgeon must wear appropriate surgical attire specifically intended for use within the operating area.

Surgical Caps and Masks: Surgical caps and masks are required for all abdominal surgeries and for castration of adult dogs. However, they are generally recommended for all surgical procedures to minimize contamination.

Surgical Hand and Arm Scrub: Surgeons must perform appropriate surgical hand and arm antisepsis prior to gloving for all abdominal surgeries and for castration of adult dogs. This can be achieved through a properly performed traditional hand and arm scrub using an appropriate surgical scrub agent, or by hand and arm washing followed by the application of a waterless surgical preparation agent, in accordance with established guidelines. For routine castration of cats and puppies, surgeons should wash their hands or perform hand antisepsis before gloving.

Surgical Gowns: The use of sterile surgical gowns, either cloth or disposable, is at the discretion of the surgeon, provided that strict aseptic technique is consistently maintained throughout the procedure.

Surgical Gloves: Single-use sterile surgical gloves are required for all abdominal surgeries and for castration of adult dogs. For routine castration of cats and puppies, either single-use sterile gloves or examination gloves are acceptable, provided hand antisepsis is performed.

Surgical Procedures

All surgical procedures must be performed by licensed veterinarians or veterinary students under the direct, on-site supervision of a licensed veterinarian. For female cats and dogs, ventral midline, paramedian, flank, and laparoscopic surgical approaches are all considered acceptable. The use of these approaches for ovariohysterectomy and ovariectomy in both pediatric and adult patients has been well-described in veterinary literature. For male cats, scrotal approaches are standard, and for male dogs, both prescrotal and scrotal approaches are acceptable for castration. The use of these approaches for castration in pediatric and adult patients is also well-documented.

General surgical principles of gentle tissue handling, meticulous hemostasis, and strict aseptic technique should always be applied. To minimize postoperative morbidity and improve overall patient outcomes, surgeons should strive to reduce surgical trauma in every possible way. This includes careful tissue handling, appropriate suture size and placement, and minimizing incision length. Small, properly placed incisions can help minimize surgical trauma while still allowing for gentle tissue handling. Hemostasis must be ensured and verified before completing any surgical procedure. Both interrupted and continuous suture patterns are acceptable for tissue closure.

Ovariohysterectomy and Ovariectomy: Numerous acceptable variations exist for surgical procedures used to sterilize female cats and dogs. The specific surgical procedure and its details, including incision length and location, and ligation techniques, will vary depending on the program, the veterinarian’s preferences, and the individual patient’s needs. In all cases, complete removal of both ovaries is mandatory. For cats, ovarian pedicle ligation can be effectively achieved by autoligation of the ovarian artery (pedicle tie). When ventral abdominal or paramedian incisions are used, abdominal closure must incorporate the external rectus fascia for adequate strength. When flank incisions are used, closure must incorporate the transversus abdominus and internal and external abdominal oblique muscles for secure abdominal wall closure.

Spaying Pregnant Cats and Dogs: When spaying pregnant cats and dogs, fetal euthanasia is not necessary to ensure humane death. Mammalian fetuses remain unconscious throughout gestation and, therefore, cannot consciously perceive pain. When a gravid uterus is removed en bloc, fetuses will not experience consciousness regardless of the stage of gestation, and death will occur painlessly. However, if the uterus and amniotic sac are opened, near-term fetuses may potentially gain consciousness. In this case, humane euthanasia of each individual fetus is required unless resuscitation efforts are medically indicated and elected by the owner.

Orchidectomy (Castration): Many acceptable variations exist for surgical procedures to sterilize male cats and dogs. The specific procedure performed will depend on the program, veterinarian preference, and individual patient needs. In all cases, complete removal of both testes is required. When a prescrotal approach is used in dogs, closure of the subcutaneous tissue and skin is required. When a scrotal approach is used in dogs and cats, incisions may be closed or left open to heal by second intention, depending on surgeon preference and patient factors.

For cryptorchid cats and dogs (animals with undescended testicles), both testes must be removed. In cases of unilateral cryptorchidism, the undescended testis should be located and removed first. If the cryptorchid testis cannot be found, the descended testis should not be removed. Referral to another veterinarian experienced in cryptorchidectomy for removal of both testes is a reasonable option in complex cases. The length and location of the surgical incision for cryptorchid animals should be chosen based on the attending surgeon’s preferences and the individual patient’s anatomy. Closure of ventral abdominal incisions for cryptorchidectomy must incorporate the external rectus fascia for adequate abdominal wall strength.

Procedures in Pediatric (6- to 16-week-old) Patients: Neutering pediatric animals is endorsed by the American Veterinary Medical Association (AVMA) and numerous other national and international veterinary and humane organizations as a crucial strategy to reduce the number of unwanted cats and dogs. Various accepted techniques for neutering pediatric cats and dogs have been described. The specific procedure performed will vary depending on the program, veterinarian preferences, and individual patient needs.

Suture Materials

Sutures or surgical clips used for tissue closure must be of biomedical grade, approved for medical use, sterile, and within their expiration date. Materials must be absorbable or inert and nonabsorbable, as appropriate for the specific tissue and procedure. Suture materials supplied in individual packets or on reels or cassettes are acceptable and should be used according to the manufacturer’s guidelines. Suture material must never be shared between patients due to the risk of disease transmission. Furthermore, with the exception of stainless steel suture, suture material cannot be effectively resterilized for future use. If reusable suture needles are used, they must be meticulously cleaned and resterilized between each patient.

Identification of Neutered Animals

Each spay-neuter program should adopt a consistent, permanent method for visually identifying animals that have been neutered. Applying a visible, standard, and easily recognizable identifying mark is highly recommended. Specifically, these guidelines recommend the use of a simple green linear tattoo to identify all neutered pet animals and ear-tipping to identify all community cats.

For all male and female pet cats and dogs, a green linear tattoo should be applied to the ventral aspect of the abdomen at the time of surgical sterilization. For female animals, the tattoo should be placed directly on or immediately lateral to the ventral midline incision. If a flank approach is used for spaying a female patient, the tattoo should still be placed in the area where a ventral midline spay incision would typically be located. For male dogs, the tattoo should be applied to the skin in the caudal aspect of the abdomen. If a prescrotal incision is used for castration, the tattoo can be applied directly to the incision. Alternatively, it can be placed in the prescrotal area immediately lateral to the prepuce. For male cats, the tattoo should be applied in the area where a ventral midline spay incision would typically be placed on a female. Sterile instrumentation should be used for applying tattoos, regardless of the application method. Acceptable methods for creating linear tattoos include:

• Applying tattoo ink or paste directly to the surgical incision after intradermal skin closure.
• Applying tattoo ink or paste to a separate, small cutaneous incision other than the surgical incision.
• Intradermal injection of tattoo ink or paste.

Regardless of the chosen method, green linear tattoos should be placed in the standardized locations described and should be distinct and readily identifiable to effectively serve as a permanent identifying mark for neutered pets.

For community cats, unilateral ear tipping (surgical removal of the distal tip of one pinna) is the recommended method for identifying neutered cats. Humane surgical removal of an ear tip is the universally accepted international standard for identifying a neutered community cat. To ensure a distinct and easily visible identifying mark, approximately one-third of the distal earflap should be removed, taking care to transect perpendicular to the long axis of the pinna, creating a straight edge. Ear notching is not recommended, as torn earflaps from fighting are common in cats and can be easily mistaken for surgically notched ears. Hemostasis of the pinna should be ensured before the recovery period ends. Instruments used for ear tipping must be thoroughly cleaned and disinfected or sterilized between patients to prevent the spread of pathogens.

Spay-neuter programs may choose to use multiple methods for identifying individual neutered animals (e.g., combining ear-tipping and tattooing, or implanting microchips, or using other forms of identification). In all cases, these guidelines recommend that neutered animals be marked using the recommended standard methods described above to ensure consistent and universal identification.

Use of Antimicrobials

Prophylactic antimicrobial administration may be considered in certain cases but is not routinely necessary for short, uncomplicated surgical procedures in healthy patients. If antimicrobials are used, they should be administered prior to surgery or as soon as a break in surgical asepsis or other clear indication for antibiotic use is recognized. Judicious antimicrobial use is always recommended to minimize the development of antimicrobial resistance.

Use of Biomedical Skin Glue

If biomedical skin glue is used to seal the skin incision, it should only be applied after satisfactory intradermal skin closure, strictly following the manufacturer’s directions. Skin glue should never be applied directly into the wound itself.

Guidelines for Postoperative Care

Ensuring a smooth transition for patients from an anesthetized state to full wakefulness and comfort before returning to their home environment requires vigilance and careful attention to detail. Successful recovery protocols are characterized by a minimal number of adverse patient events and a rapid return to normal behaviors. Prompt recognition and management of any problems, combined with open communication with clients, are crucial for minimizing negative consequences.

Recovery

Patients should be thoroughly assessed immediately after surgery to identify any conditions requiring immediate attention or communication to recovery staff. The recovery environment should be designed to minimize the risk of complications and staff injury. Designated recovery areas should allow for continuous, direct visual observation of each patient. Patient recovery should occur on a secure, level surface, such as the floor or the bottom of a cage. Animals recovering on elevated surfaces must be protected from accidental falls. All recovery areas should be clean, dry, and warm. Loud noises should be minimized to reduce the incidence of emergence delirium or stress.

During recovery, animals should be positioned to prevent airway obstruction. This is achieved by ensuring each patient’s head and neck are carefully placed in slight extension and in straight alignment with the thorax. Pediatric patients and others at risk of hypoglycemia may benefit from transmucosal administration of sugar supplements (e.g., corn syrup or dextrose solution) during recovery. For pediatric patients, recovery with littermates is recommended when feasible, as it can provide warmth and reduce anxiety associated with separation. However, given that littermates often pile on top of each other to sleep, inadvertent respiratory compromise can occur when littermates in various stages of recovery are housed together. When littermates are housed together during recovery, continuous direct observation is essential until each animal is fully oriented and strongly ambulatory. To maximize personnel safety, community cats should be returned to their traps or transport carriers while still unconscious for recovery monitoring. In this case, cats must be carefully monitored to ensure that their movements or turning within the confined space during recovery do not compromise airway patency. Gentle rocking or tilting of the trap or carrier may be necessary to safely reposition the cat’s head and neck and maintain an open airway.

Postoperative Complications

Recovering patients must be continuously observed for postoperative complications related to anesthesia or surgery. Potential complications can include hemorrhage, cardiorespiratory depression or compromise, pain, hypothermia, hyperthermia, distress, anxiety, vomiting, regurgitation, aspiration, or any other condition that could impede recovery. Postanesthetic hyperthermia has been reported in cats, most often following opioid administration, although it can also be associated with other drugs like ketamine and may be multifactorial. Treatment of hyperthermic patients may include selective drug reversal and supportive care, such as removing external heat sources, active cooling, and sedation, while ensuring adequate analgesia.

Anesthesia-related deaths are most common during the postoperative recovery period, especially within the first 3 hours after surgery. The following parameters should be closely monitored during recovery:

• Heart rate and pulse quality
• Respiratory rate and character
• Airway patency
• Mucous membrane color
• Signs of pain and anxiety (e.g., restlessness, vocalization)
• Body temperature
• Degree of arousal or sedation
• Movement and ability to ambulate

Any identified problems should be triaged and addressed promptly and appropriately.

Analgesia

Postoperative analgesia requirements will vary between individual patients due to differences in surgical complexity, surgical technique, patient age, and individual responses to pain and analgesic agents. If NSAIDs were not administered before or during surgery, they may be given postoperatively, either alone or in combination with additional opioids or other analgesic agents, as needed to ensure adequate pain management.

Because some patients will require analgesia beyond the immediate 24-hour postoperative period, a plan should be in place to address ongoing pain management after discharge. Options include dispensing pain medication to the owner, providing a written prescription, or giving contact information for assistance in obtaining additional analgesic medication if needed. Clinicians must be prepared to adjust analgesic protocols to meet the specific needs of individual patients after surgery. Some oral analgesic agents, such as tramadol, are associated with greater variability in response than others. Because multimodal analgesia typically provides improved pain control for most patients, its use is recommended whenever possible for postoperative pain management.

It is critical to remember that postoperative pain medication is not a substitute for effective preoperative analgesia and minimally traumatic patient preparation and surgical techniques. If patients frequently exhibit ongoing signs of pain or discomfort postoperatively, or if they induce self-trauma to surgical wounds, analgesic protocols and patient preparation and surgical techniques should be carefully reviewed to identify factors that may be contributing to these postoperative problems.

Anesthetic Reversal

Reversal of sedative, anesthetic, or analgesic agents may be performed when patients experience prolonged recoveries or in emergency situations. Potential benefits of anesthetic reversal include reducing or alleviating cardiorespiratory depression associated with anesthetic agents, hastening recovery, and promoting the return of thermoregulation. Potential drawbacks of rapid and complete reversal include increased anxiety and reduced analgesia. A recent study indicated that partial reversal of α2-adrenoceptor agonists can be associated with shorter recovery times without compromising patient analgesia when using a multimodal anesthetic protocol. Rapid IV administration of reversal agents should be avoided except in true emergency situations.

Return to Patient Housing

When returning patients to their assigned housing areas after recovery, verifying each individual animal’s identification and specific cage assignment is imperative to prevent errors. Following initial recovery, patients should be periodically re-evaluated for any changes in mental status or overall condition that could indicate potential complications, stress, or pain. Cleanliness of the housing area should also be carefully monitored. Pediatric, geriatric, frail, and at-risk patients should be protected from hypoglycemia and dehydration by offering small amounts of food and water as soon as appropriate, based on their neurologic status, including mentation and swallowing reflexes.

Prolonged confinement without opportunities for urination and defecation away from their enclosure can increase patient stress and discomfort. This issue can be exacerbated by perioperative fluid administration and certain anesthetic agents, such as α2-adrenoceptor agonists, which can increase urine output. Additionally, confinement itself can inhibit elimination behavior in some patients. For these reasons, expressing the patient’s bladder, in both male and female patients, during anesthesia can improve comfort in the immediate postoperative period. For overnight stays, an absorbent substrate, such as paper, litter, or bedding, should be provided for cats. Dogs should be walked, if safe for staff, housed in enclosures like runs that allow for elimination away from the resting area, or provided with an absorbent substrate in their enclosures. Traps housing community cats should be covered to reduce patient stress and should be elevated to allow urine and feces to fall through the wire bottoms away from the patient or lined with absorbent material that can be safely changed if soiled.

Discharge of Patients

Patients must be thoroughly evaluated immediately prior to discharge. Postoperative evaluations should include assessments for normal mentation, respiration, and adequate analgesia. Surgical incisions should be examined to ensure that the skin edges are clean, dry, and well-apposed, unless this is contraindicated by fractious or feral behavior. Before discharge, cats and dogs should be sternal, alert, and responsive. In addition, dogs should be able to ambulate normally.

Trapped community cats should be returned to their familiar environment or site of capture when they are no longer under the influence of anesthesia (i.e., mentally alert, oriented, and able to mobilize). Balancing the need to ensure safe recovery with the stress of prolonged confinement is necessary, but in most cases, release on the day following surgery is indicated to minimize stress and facilitate their return to their territories.

Postoperative Care Instructions

Clients must be provided with clear and comprehensive instructions for postoperative care. Both written and verbal instructions should be provided whenever possible to ensure client understanding. While specific instructions may vary between programs, important topics to consider including are:

• A summary of the surgical procedures performed.
• A description of normal and abnormal recovery behavior to expect.
• Signs of discomfort or pain that may indicate a problem.
• Instructions on caring for and monitoring the surgical incision site.
• Guidance on when to offer food and water postoperatively.
• Any exercise restrictions or limitations for the recovery period.
• Detailed medication instructions, if any medications are dispensed.
• Any other special instructions tailored to the individual patient’s needs.
• Clear instructions for notifying the clinic about any postoperative complications, including contact information for questions or concerns.
• A list of changes in the animal’s status that require urgent veterinary re-evaluation.
• Instructions for accessing emergency veterinary care if needed after hours.
• Recommendations for ongoing veterinary care with a full-service veterinary practice for future health needs.

Guidelines for Operations Management

Operations management is a proactive approach involving continuous, strategic planning, control, and improvement to effectively and efficiently deliver an organization’s services. This approach is highly recommended for enhancing performance in HQHVSN programs. Operations management encompasses crucial aspects of clinic direction and personnel, such as standardized workflows, training, teamwork, and planning, all integral to delivering high-quality health care services. The ultimate goal of operations management is the strategic organization of logistics and procedures to improve the safe and efficient delivery of quality patient services.

Process-Oriented Management of Surgery

Process-oriented management involves clearly defining each step of the surgical process, from patient intake to discharge. Patient care is delivered as a series of coordinated hand-offs, where specific tasks are performed in accordance with accepted medical guidelines at each stage. This structured approach promotes consistent, high-quality care, reducing the risk of errors and optimizing patient outcomes. By defining and implementing standard procedures at each step of the process, HQHVSN programs can enhance the quality of care, minimize risks for both patients and staff, optimize patient outcomes, and improve both time and cost efficiency.

Use of Standard Operating Procedures (SOPs) and Checklists

Implementing Standard Operating Procedures (SOPs) is highly recommended to ensure consistent care and effectively manage workflow as patients move through the surgical process. SOPs should reflect current best practice guidelines and be flexible enough to accommodate the unique needs of individual patients. Unnecessary deviations from established SOPs increase the potential for errors or omissions and should be minimized. Medical records can be designed to function as checklists, prompting necessary actions, confirming task completion, and ensuring accurate documentation at each stage of the process. Numerous studies have demonstrated that the regular use of customized checklists significantly improves compliance with SOPs, reduces mistakes, and ultimately improves patient outcomes in medical settings. The use of computerized medical records can further enhance patient care and safety by facilitating the analysis of trends in patient outcomes and program performance.

Data Collection and Analysis

Systematic data collection and analysis of patient outcomes in HQHVSN programs is highly recommended to identify, characterize, and track trends in patient outcomes. This data-driven approach provides a basis for the periodic refinement of existing protocols and procedures, ensuring continuous improvement. Research in human medicine on error and failure analysis highlights the significant benefits of this approach and provides a valuable model for HQHVSN programs. Morbidity and mortality data, including both perianesthetic and postoperative complications and deaths, should be meticulously recorded. This data can be categorized by program type, veterinarian, animal species, surgery type, or other relevant criteria to aid in identifying potential risk factors and to inform subsequent protocol refinements.

As in any veterinary practice, recognizing patterns and trends in patient outcomes is crucial for reducing morbidity and mortality rates. Pattern detection alerts the healthcare team to areas where the likelihood of complications is highest, allowing for proactive protocol improvements and increased vigilance at critical points in the process. High-quality, high-volume spay-neuter programs can achieve morbidity and mortality rates that are similar to or even lower than those typically seen in small animal general practice settings, demonstrating the effectiveness of standardized, high-quality protocols.

Staff Training

Adequate initial training, as well as ongoing skill and knowledge development, is essential for all program personnel to ensure proper animal care and safety, as well as staff safety and well-being. A structured training plan based on the program’s SOPs allows for comprehensive and consistent instruction of new staff members and volunteers. Training methods can include written materials, instructional videos, live demonstrations, practice drills, shadowing experienced personnel, and supervised performance of job duties. Before unsupervised work duties are permitted, demonstrated knowledge and proficiency in all required tasks, including technical skills, should be verified and documented. All staff members should participate in relevant continuing education opportunities to stay updated on best practices and to satisfy any state-mandated continuing education requirements for their roles.

Leadership

Leadership that values and empowers team members has been shown to improve program performance, increase employee satisfaction and well-being, and reduce employee turnover rates. Effective leadership is also associated with improvements in both staff and patient safety and can mitigate employee work-related stress, increasing job satisfaction. This is particularly crucial in the context of HQHVSN programs, where employee stress and work dissatisfaction are known risk factors for musculoskeletal pain and decreased surgical performance, as well as for depression and suicidal ideation among veterinarians. Leadership skills can be effectively taught, and leadership training is a valuable intervention that should be considered for anyone entering a leadership position within a spay-neuter program.

Personnel Health and Safety

High-quality, high-volume spay-neuter programs should prioritize fostering a safe and healthy work environment for all program personnel. Efforts to reduce environmental stress and unnecessary distractions are beneficial for both staff and patient well-being and can enhance overall safety. Common distractions to address include loud music, loud conversations, unnecessary foot traffic in surgical areas, barking dogs, slamming cage doors, and non-essential cell phone use during work hours.

As with any type of veterinary practice, spay-neuter programs must implement necessary precautions to ensure chemical and biological safety, manage waste anesthetic gas exposure, and ensure the safe disposal of sharp instruments. Programs should also minimize the risk of occupational noise exposure, zoonotic disease transmission, physical injuries, compassion fatigue, and other work-related health problems. Badge monitoring for anesthetic waste gases is available and recommended as a means of assessing personnel exposure levels and ensuring adequate scavenging systems are in place.

Patient handling is a significant physical health risk for HQHVSN program staff. Animal bites, musculoskeletal strains from lifting animals, and injuries from slips and falls during animal handling are among the most frequent types of veterinary employee injuries. Implementing low-stress animal handling techniques, using appropriate restraint methods and equipment, and providing training in safe lifting and handling practices can significantly decrease stress for both animals and staff while enhancing overall safety. Whenever possible, lift tables, stretchers, or blankets should be used to facilitate the movement of both conscious and anesthetized patients, reducing physical strain on staff. When such equipment is not available, a two-person lift, using proper body mechanics (bent knees and a straight back), will reduce the risk of injury when lifting large dogs.

Workplaces should also strive to create a safe and supportive environment where mental health issues are not stigmatized. Shelter veterinarians are at increased risk of developing depression, and many spay-neuter veterinarians share demographic risk factors that may place them at greater risk than other veterinarians for experiencing depression, burnout, compassion fatigue, or suicidal ideation. Improving access to mental health care can be achieved by posting information about mental health services, support groups, and suicide hotline numbers in staff areas, and by providing flexibility in staff scheduling or duties to accommodate mental health treatment. Workers can be trained to recognize early warning signs of stress, compassion fatigue, and depression in themselves and their colleagues. Programs should foster a supportive atmosphere and provide readily available referrals to mental health services when needed.

Perioperative Ergonomics

Optimizing perioperative ergonomics in HQHVSN programs is crucial for occupational health and safety, particularly given the repetitive nature of the work. Ergonomics directly impacts surgeon health, productivity, and long-term sustainability in this demanding field. While some HQHVSN surgeons have worked for decades without experiencing work-related pain, many experience some degree of musculoskeletal discomfort that they attribute, at least partially, to their work. Discomfort tends to be more pronounced in surgeons who spend more hours in surgery each week and in those with longer careers in HQHVSN practice. Veterinarians experiencing musculoskeletal discomfort should seek medical attention early, rather than allowing pain to become chronic.

Surgeons in human practice who alternate between sitting and standing during surgery, or who primarily sit, report less general fatigue and less fatigue specifically in the spine and lower limbs. For surgeons who stand during surgery, the operating table should be adjusted to a comfortable height for each individual and each procedure. Standing surgeons may experience reduced discomfort and fatigue in their lower limbs by using thick but firm elastic floor mats in the operating room. Cushioned shoes and insoles can also help decrease fatigue during prolonged standing.

Being able to change position during an operation or between successive short operations is associated with decreased fatigue and pain after surgery. Incorporating micropauses of 15 to 30 seconds, taken multiple times per hour, can reduce discomfort and fatigue and increase accuracy, especially when combined with active stretching or exercises that release neck and shoulder tension inherent in surgical posture.

Surgical tasks in HQHVSN programs often involve repetitive movements that may require force or be performed with awkward hand and wrist positioning. While each of these factors alone (repetition, force, and posture) has a moderate association with musculoskeletal discomfort in the hand and wrist, when combined, their association with musculoskeletal discomfort becomes strong. Using efficient and gentle surgical techniques, and ensuring surgical instruments are appropriately maintained and sharp, can help minimize these ergonomic risks and reduce strain on the surgeon.

Regulatory and Legal Considerations

These guidelines are intended to supplement, not replace, any applicable laws and regulations. In cases of conflict, veterinarians and program administrators are encouraged to comply with the more stringent requirements. Local, state, and federal laws and regulations, including those from the Drug Enforcement Administration (DEA) and the Occupational Safety and Health Administration (OSHA), all have implications for HQHVSN program operations. Veterinarians and administrators should consult local zoning and environmental regulations, state veterinary practice acts, and state boards of veterinary medicine, pharmacy, and public health for specific requirements in their respective jurisdictions. Consulting with both an attorney and an accountant is recommended to ensure full compliance with all applicable laws and regulations governing veterinary practice and non-profit operations.

Conclusions

Spay-neuter programs are an integral and essential component of both veterinary medicine and community well-being. They often provide initial veterinary care to at-risk and underserved animals, and for many clients, they represent their first positive exposure to professional veterinary services. When spay-neuter services are accessible and affordable, pet owners are better able to provide essential initial care for their pets, reducing the risk of relinquishment due to financial constraints or lack of access to care. For many pets, these programs ultimately serve as gateways to a lifetime of care through referral to full-service veterinary practices for ongoing preventive care and medical needs in the future.

By consistently following these 2016 veterinary medical care guidelines, spay-neuter programs can provide high-quality veterinary care and effectively achieve their missions of humanely neutering large numbers of cats and dogs. Currently, HQHVSN programs represent the most effective approach to reducing shelter impoundment and euthanasia of cats and dogs on a large scale. Furthermore, they are the most financially responsible and humane way for communities to increase the number of cats and dogs that are sterilized, thereby addressing pet overpopulation at its root. By actively participating in this rapidly evolving practice area, veterinarians play a vital role in alleviating pet overpopulation and decreasing the untimely euthanasia of countless cats and dogs, while providing essential HQHVSN services to animals that would otherwise be unlikely to receive such care.

Acknowledgments

Supported by PetSmart Charities Inc and the American Society for the Prevention of Cruelty to Animals.

Presented in abstract form at the American Board of Veterinary Practitioners Symposium, New Orleans, November 2015.

The authors thank Ms. Bert Troughton for expert facilitation of the task force’s work.

ABBREVIATIONS

ASV	Association of Shelter Veterinarians
HQHVSN	High-quality, high-volume spay-neuter

Footnotes

[a.] Ambu Inc, Glen Burnie, Md.

[b.] Robertson SA. Anesthesia protocols for early kitten sterilization and feral cat clinics (oral presentation). 77th Annual Western Veterinary Conference, Las Vegas, February 2005.

[c.] Reuss-Lamky H. Waste anesthetic gases—the invisible threat (oral presentation). 24th Annual American College of Veterinary Internal Medicine Conference, Louisville, Ky, May–June 2006.

[d.] Griffin B. Standards of care for high-quality, high-volume spay-neuter (oral presentation). North American Veterinary Conference, Orlando, Fla, February 2008.

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