Flow-controlled expiration reduces positive end-expiratory pressure requirement in dorsally recumbent, anesthetized horses.
Authors: Brandly Jerrianne E, Midon Monica, Douglas Hope F, Hopster Klaus
Journal: Frontiers in veterinary science
Summary
Equine anaesthetic mortality substantially exceeds that of other species, partly due to compromised pulmonary gas exchange and subsequent hypoxaemia during dorsal recumbency—a common surgical position. Brandly and colleagues investigated whether flow-controlled expiration (FLEX), a ventilatory mode that slows expiratory flow and reduces alveolar collapse, could minimise the positive end-expiratory pressure (PEEP) requirements needed to maintain adequate oxygenation in dorsally recumbent anaesthetised horses. Following an alveolar recruitment manoeuvre, FLEX-ventilated horses required significantly lower PEEP levels to prevent atelectasis compared to conventionally ventilated controls, whilst maintaining comparable gas exchange parameters. For anaesthetic and surgical teams, these findings suggest that adopting FLEX ventilation during equine general anaesthesia—particularly for procedures necessitating dorsal recumbency—could reduce ventilator-induced lung injury risk and potentially improve perioperative oxygenation without escalating PEEP to problematic levels. The clinical implication is particularly important given equine anaesthetic complications remain a persistent welfare and economic concern; optimising ventilatory management represents a tangible intervention to enhance patient safety during prolonged procedures.
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Practical Takeaways
- •FLEX ventilation may reduce peri-anesthetic mortality in horses by improving oxygenation through lower PEEP requirements and better alveolar recruitment during dorsal positioning
- •Consider FLEX as a ventilatory mode option for anesthetized horses, particularly those requiring prolonged dorsal recumbency where gas exchange impairment is a concern
- •This technique addresses a significant clinical problem in equine anesthesia where conventional ventilation frequently results in hypoxemia and compromised gas exchange
Key Findings
- •Flow-controlled expiration (FLEX) ventilation reduces the positive end-expiratory pressure (PEEP) requirement needed to maintain alveolar recruitment in anesthetized horses in dorsal recumbency
- •FLEX linearizes expiratory gas flow and reduces the rate of lung emptying, preventing alveolar collapse
- •FLEX improves gas exchange and pulmonary mechanics during equine general anesthesia