Risk factors associated with hypoxaemia in horses undergoing general anaesthesia: A retrospective study.

Authors: Hovda Tyne, Love Lydia, Chiavaccini Ludovica

Journal: Equine veterinary journal

DOI: 10.1111/evj.13541 PubMed: 34796547Log in to save

Summary

# Editorial Summary Hypoxaemia during equine general anaesthesia remains inadequately characterised, particularly in elective settings, despite its clinical significance. This retrospective analysis of 774 anaesthetic records (708 horses, 2017–2020) compared the prevalence and risk factors for hypoxaemia (defined as arterial oxygen partial pressure ≤80 mm Hg) between horses undergoing exploratory laparotomy and elective procedures, employing multivariable logistic regression to identify independent predictors. Emergency laparotomy cases demonstrated substantially elevated hypoxaemia risk, with 23% becoming hypoxaemic compared to only 3.8% of elective cases—representing a six-fold increased likelihood. In emergency settings, bodyweight exceeding 550 kg, large intestinal pathology, and peak inspiratory pressure (PIP) above 30 cmH₂O emerged as significant risk factors, whilst soft tissue procedures combined with elevated PIP predicted hypoxaemia during elective anaesthesia. These findings emphasise the need for heightened perioperative vigilance in heavier horses undergoing emergency abdominal surgery and warrant consideration of ventilatory management strategies to maintain PIP ≤30 cmH₂O, providing evidence-based targets for practitioners to optimise oxygenation and inform pre-operative risk stratification in both emergency and planned equine procedures.

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Practical Takeaways

•Emergency exploratory laparotomy cases require heightened vigilance for hypoxaemia; expect it in approximately 1 in 4 cases, particularly in heavier horses with large intestinal pathology
•Monitor peak inspiratory pressure closely during general anaesthesia regardless of procedure type—values exceeding 30 cmH₂O indicate increased hypoxaemia risk and warrant ventilation strategy review
•Elective soft tissue procedures carry lower but measurable hypoxaemia risk; routine oxygenation monitoring and preparedness for intervention remain essential

Key Findings

•Hypoxaemia occurred in 23% of horses undergoing exploratory laparotomy versus 3.8% undergoing elective procedures (P < 0.001)
•Horses undergoing exploratory laparotomy were over 6 times more likely to become hypoxaemic than those undergoing elective procedures
•Bodyweight >550 kg, large intestinal lesions, and peak inspiratory pressure >30 cmH₂O were independent risk factors for hypoxaemia in exploratory laparotomy cases
•Soft tissue procedures and peak inspiratory pressure >30 cmH₂O were significant predictors of hypoxaemia during elective anaesthesia

Conditions Studied

hypoxaemia during general anaesthesiaexploratory laparotomyelective surgical procedureslarge intestinal lesions

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