The ASA Physical Status Classification: What Is the Evidence for Recommending Its Use in Veterinary Anesthesia?-A Systematic Review.
Authors: Portier Karine, Ida Keila Kazue
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: ASA Physical Status Classification in Veterinary Anaesthesia Whether the American Society of Anesthesiologists' Physical Status (ASA PS) classification meaningfully predicts anaesthetic risk in veterinary patients has long remained contested, prompting Portier and Kazue to conduct a systematic review and meta-analysis of observational studies spanning 258,298 animals (dogs, cats, rabbits, and pigs) to establish whether evidence supports its clinical use. Across 15 prospective and retrospective studies, animals classified as ASA PS ≥III showed substantially elevated perioperative mortality: dogs faced 3.26-fold greater risk of anaesthesia-related death within 24 hours, whilst cats and rabbits experienced 4.83-fold and 11.31-fold increases respectively within 72 hours post-anaesthesia, compared to those with ASA PS <III. The analysis also identified a 2.34-fold increased risk of severe intraoperative hypothermia in dogs and cats with higher ASA scores. These findings provide robust quantitative evidence that ASA PS classification, despite its simplicity, serves as a reliable prognostic tool for identifying patients at heightened risk of anaesthetic complications and mortality. For practitioners—whether veterinary surgeons, anaesthetists, or those involved in pre-operative assessment—incorporating ASA PS scoring into pre-anaesthetic evaluation protocols represents a straightforward, evidence-based method to stratify risk and inform client counselling and anaesthetic planning, particularly in compromised patients.
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Practical Takeaways
- •Use ASA-PS scoring routinely before anesthesia—animals rated ASA III or higher require heightened perioperative monitoring and risk mitigation strategies
- •Implement aggressive hypothermia prevention protocols (warm fluids, heating pads, insulation) for higher ASA-PS animals, as they are significantly more vulnerable to severe intraoperative heat loss
- •Higher ASA scores indicate substantially elevated mortality risk up to 72h post-anesthesia; counsel owners accordingly and plan closer post-operative observation for ASA-PS ≥III cases
Key Findings
- •Dogs with ASA-PS ≥III had 3.26× higher risk of anesthesia-related death within 24h compared to ASA-PS <III
- •Cats with ASA-PS ≥III had 4.83× higher risk of anesthesia-related death within 72h; rabbits had 11.31× higher risk
- •Dogs and cats with ASA-PS ≥III had 2.34× greater risk of severe intraoperative hypothermia
- •ASA Physical Status classification is a valuable, simple, and practical prognostic tool for identifying anesthetic risk in veterinary patients