Arterial oxygen tension and pulmonary ventilation in horses placed in the Anderson Sling suspension system after a period of lateral recumbency and anaesthetised with constant rate infusions of romifidine and ketamine.
Authors: François I, Lalèyê F-X, Micat M, Benredouane K, Portier K
Journal: Equine veterinary journal
Summary
# Editorial Summary This 2014 study investigated whether suspending anaesthetised horses in an Anderson Sling after lateral recumbency improves their cardiopulmonary function compared to remaining recumbent, using six Standardbred horses maintained under romifidine and ketamine infusions with arterial blood gas sampling throughout the procedure. Horses recovered in the sling demonstrated significantly better arterial oxygen tension, lower alveolar-arterial oxygen gradients, and reduced respiratory effort in the latter phase of anaesthesia (40–100 minutes), alongside lower blood lactate concentrations at standing, suggesting less tissue hypoxia and metabolic stress. Conversely, horses remaining recumbent showed progressive hypoxaemia and compensatory hyperventilation, though notably the sling group developed elevated arterial CO₂ tension and increased creatine kinase activity by 24 hours post-recovery—indicators of mild muscular stress from suspension. For practitioners managing anaesthetic recoveries, particularly in cases of perioperative hypoxaemia, early mobilisation into a sling appears beneficial for oxygenation and metabolic recovery, though careful monitoring for myopathy risk and appropriate padding protocols remain important, especially for prolonged suspension periods.
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Practical Takeaways
- •Using Anderson Sling suspension for recovery after general anaesthesia, particularly in horses at risk of hypoxia, can improve oxygenation and recovery quality compared to remaining in lateral recumbency
- •Sling suspension may reduce post-operative metabolic stress and improve arterial oxygen tension, which is beneficial for compromised horses during anaesthetic recovery
- •Monitor for elevated creatine kinase activity at 24 hours post-sling suspension as an indicator of muscular exertion during positioning
Key Findings
- •Horses in Anderson Sling suspension had significantly higher arterial oxygen tension during the second anaesthetic period (P = 0.001) compared to those remaining in right lateral recumbency
- •Alveolar-arterial oxygen gradient was lower in sling-suspended horses (P = 0.005), indicating improved oxygenation efficiency
- •Recovery quality was significantly better in the Anderson Sling group than in the recumbent group (P = 0.01)
- •Lactate concentrations at standing recovery were higher in recumbent horses (P = 0.007), suggesting better metabolic status in sling-suspended horses