Patient recovers on Darvall’s forced air warming blankets. Photo courtesy Drs. Dunlop and Jorgensen Keeping animals warm during anesthesia has long been recognized as an important step in ensuring patient safety. Yet in many practices, temperature management is still treated as a reactionary approach, beginning only after a patient’s body temperature has already begun to fall. Clinics can adopt a proactive approach through leveraging pre-warming protocols, warming patients before anesthesia begins, to help prevent peri-anesthetic hypothermia rather than trying to reverse it later. The shift reflects a simple principle: it is far easier to keep an animal warm than to warm one that has already become cold. Why hypothermia happens so quickly Hypothermia during anesthesia is one of the most common complications seen in veterinary medicine. Studies suggest up to 80 percent of anesthetized dogs and cats experience some degree of hypothermia during procedures.1 The reason for this is sedatives and anesthetic agents suppress the body’s normal ability to regulate temperature and also prevent shivering. They cause vasodilation, meaning blood moves away from the body’s warm core toward the cooler extremities, and thus dissipates heat. Research shows dogs and cats may lose several degrees of body temperature within the first 15 to 30 minutes following induction of anesthesia.2 The process often begins even earlier, as once premedication is given, patients can already experience a mild drop in core temperature. Other additional factors which can further accelerate heat loss include: Clipping and wetting the coat during surgical preparation Cold operating environments Open body cavities during surgery Breathing cold anesthetic gases Small animals are particularly vulnerable because their higher surface-area-to-volume ratio means heat escapes more quickly. Why temperature matters for recovery While hypothermia may seem like a minor issue, its clinical effects can be significant. This is because lower body temperatures can slow heart rate and respiration, reduce drug metabolism, and prolong recovery times. Hypothermic patients often take longer to regain consciousness and may experience disorientation, shivering, and discomfort during recovery.3 Shivering can also place stress on surgical sites and increase post-operative pain. More concerningly, many anesthetic complications occur during recovery. Approximately one in 500 animals die during anesthesia or sedation, and around half of those deaths occur during the recovery phase, when patients are particularly vulnerable to temperature-related complications.4 For veterinary teams actively focused on improving outcomes, better temperature management has therefore become a priority. A patient using a heated breathing circuit. Photo courtesy Drs. Colin Dunlop and Norm Jorgensen Prevention rather than reaction Traditionally, many warming strategies have focused on intraoperative warming with heated blankets or devices. While these remain important, they often begin after the patient has already experienced a significant temperature drop. Pre-warming changes that timeline. By warming patients before induction, veterinary clinics can raise the temperature of the skin and peripheral tissues (Figure 1). This helps reduce heat redistribution from the body’s core once vasodilation occurs. Even a 30- to 40-minute pre-warming period can increase peripheral temperatures by several degrees, significantly reducing the steep temperature decline that typically occurs immediately after induction. In practical terms, this means patients start anesthesia with a thermal “buffer,” making it easier to maintain normal body temperature throughout the procedure. There are also workflow advantages, as veterinary teams report pre-warming multiple animals before procedures can be more efficient than trying to warm a severely hypothermic patient during recovery. In many cases, practices find they can pre-warm several patients in the time it would take to re-warm one cold animal.5 Rethinking warming blankets As pre-warming protocols become more common, practices are also reassessing the equipment used to deliver that warmth. One assumption often made in clinics is that reusable warming blankets are the most practical or sustainable option. However, in everyday veterinary settings, the reality can be more complex. Reusable blankets are frequently subjected to heavy wear. Animals may chew or claw on them, and repeated washing can degrade the fabric structure, with reusable blankets losing much of their efficiency even after the first wash. Over time, this can increase the material’s porosity, reducing the blanket’s ability to retain and distribute warm air effectively. When airflow escapes rather than inflating the blanket’s internal air pockets, heat distribution becomes uneven and warming efficiency drops. Disposable blankets, by contrast, are designed to maintain consistent airflow and structure throughout their use. Many veterinary teams now use them not as single-patient items but for multiple uses over several days, allowing them to warm patients repeatedly within a clinical workflow. Cost considerations can also play a role. While reusable blankets may have a higher upfront cost, averaging $150, ongoing expenses for laundering, repair, and replacement can add up over time. In contrast, disposable options may cost a fraction of the price, averaging $12, and require no washing or repair. Another practical advantage is versatility. Some veterinary-specific blanket designs are shaped to fit both kennels and operating tables, allowing animals to be pre-warmed comfortably before surgery and to continue receiving warmth during recovery. A canine patient on Darvall’s forced air warming blankets and heated breathing circuit to maintain its temperature during surgery. Photo courtesy Drs. Jorgensen and Dunlop A shift in mindset Ultimately, the growing adoption of pre-warming reflects a broader change in how veterinary teams approach peri-anesthetic care. Rather than viewing hypothermia as an unavoidable side effect of anesthesia, clinicians are increasingly recognizing it as a preventable risk factor that can be addressed earlier in the patient’s journey. With improved warming technologies and greater awareness of temperature management strategies, practices can implement proactive warming protocols to help improve both patient outcomes and clinical efficiency. Colin Dunlop, BVSc, DACVAA, is a veterinary anaesthesiologist and Diplomate of the American College of Veterinary Anaesthesiologists. with extensive experience in clinical practice, research, and veterinary education. Dr. Dunlop is the CEO of Darvall. Norm Jorgensen, DVM, has decades of experience in large and small animal practice, as well as in veterinary innovation. He is the CEO of Jorgensen Laboratories. References Dunlop, Colin. “World Small Animal Veterinary Association World Congress 2014.” In Solving Perianaesthetic Hypothermia, 2014. https://www.vin.com/apputil/content/defaultadv1.aspx?pId=12886&catId=57123&id=7054801&ind=486&objTypeID=17. Sage AM, Bossert JL, Brunstein KA, Farrow AF, Perregrino AN, Clark-Price SC. Retrospective investigation of decreasing body temperature trends during anaesthesia in dogs. Vet Rec. 2023 Aug-Feb 19;193(4):e2586. doi: 10.1002/vetr.2586. Epub 2023 Jan 16. PMID: 36646653. Robertson, Sheilah. “World Small Animal Veterinary Association World Congress.” In Hypothermia - More Important Than You Believe, 2015. https://www.vin.com/apputil/content/defaultadv1.aspx?pId=14365&id=7259242. Brodbelt , David C. “The Confidential Enquiry into Perioperative Small Animal Fatalities,” 2006. https://www.rvc.ac.uk/Media/Default/staff/files/dbrodbelt-thesis.pdf Parker, Stacey. “Avoiding Hypothermia in Patients under General Anaesthesia for Dental and Oral Surgery.” improveinternational.com, October 23, 2025. https://improveinternational.com/uk/clinical-library/avoiding-hypothermia-in-dental-patients-under-anaesthesia.
