Lidocaine constant rate infusion in isoflurane anesthetized neonatal foals.
Authors: Lambertini Carlotta, Spaccini Francesca, Mazzanti Alessia, Spadari Alessandro, Lanci Aliai, Romagnoli Noemi
Journal: Frontiers in veterinary science
Summary
# Lidocaine infusion in neonatal foal anaesthesia: cardiovascular considerations without isoflurane-sparing benefits Lidocaine constant rate infusion is routinely used in adult equine anaesthesia to reduce volatile anaesthetic requirements and provide analgesia, yet its effects in neonatal foals remain poorly characterised. Researchers administered lidocaine at 0.05 mg/kg/min intraoperatively to twelve foals under isoflurane anaesthesia and compared cardiovascular parameters, isoflurane consumption and recovery quality against a historical control group of eleven foals receiving standard anaesthesia without lidocaine. Whilst heart rate decreased significantly in the lidocaine group compared with controls (71.2 versus 87.1 bpm; p = 0.0236), the drug provided no reduction in isoflurane requirements and did not alter extubation times, time to sternal recumbency, standing, or overall recovery quality between groups; notably, inotropic support was required in seven of twelve lidocaine-treated foals and nine of eleven controls, showing no statistical difference. The critical implication for equine anaesthetists is that whilst lidocaine does not disrupt foal recovery, its negative chronotropic effect warrants careful haemodynamic monitoring, particularly since neonatal foals depend on heart rate maintenance to sustain cardiac output and peripheral perfusion—a consideration that may outweigh any analgesic benefits in this age group.
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Practical Takeaways
- •Lidocaine infusion in anesthetized foals does not reduce isoflurane needs or improve recovery, so it offers no pharmacoeconomic benefit for routine neonatal foal surgery
- •The significant bradycardic effect of lidocaine in foals is concerning given their dependence on heart rate for maintaining cardiac output—continuous monitoring is essential if used
- •Consider alternatives to lidocaine for analgesia in neonatal foals under general anesthesia, as the cardiovascular risks may outweigh benefits
Key Findings
- •Lidocaine infusion at 0.05 mg/kg/min significantly reduced heart rate intraoperatively (71.2 vs 87.1 bpm, p=0.0236) compared to control foals
- •Lidocaine did not reduce isoflurane requirements in anesthetized foals, contrary to findings in adult horses
- •Lidocaine did not improve recovery quality or alter extubation times, with no significant differences in time to sternal recumbency (p=0.6) or standing
- •Inotropic support was required in 7/12 lidocaine-treated foals and 9/11 controls (p=0.371), indicating bradycardia may compromise cardiac output in neonates