Cardiopulmonary resuscitation in anaesthetised foals

Abstract

The case report by Papa et al. (2025) describes the successful management of a ureteral tear in a foal. While the foal in this case report did well under anesthesia, this article highlights several important patient factors that can lead to cardiopulmonary arrest under general anesthesia.

Foals under 1 month of age are particularly susceptible to complications under general anesthesia with an increased risk of death compared to adults (Johnston et al., 2002). Multiple case reports have demonstrated that perianaesthetic cardiac arrest can be successfully managed in foals (Haga et al., 2011; Marolf et al., 2018; Wiechert-Brown et al., 2022). In 2024, the RECOVER Initiative published an updated version of its Cardiopulmonary Resuscitation (CPR) guidelines, incorporating revised recommendations (Burkitt-Creedon et al., 2024). This clinical commentary aims to present these recommendations in the context of perianaesthetic cardiopulmonary resuscitation in foals.

Cardiopulmonary arrest (CPA) in foals is most commonly described due to patient-related factors surrounding parturition, such as prematurity or dysmaturity, asphyxia and neonatal maladjustment. CPA in anaesthetised foals can be due to a combination of anaesthetic or patient-related factors.

Signs of impending cardiopulmonary failure in anaesthetised patients include hypotension (<40 mmHg), marked elevations in lactate, apnoea, agonal breathing, absent peripheral pulses, nonresponsive mydriatic pupils, bradycardia or tachycardia. In anaesthetised patients, detection of CPA is typically characterised by a loss or sudden severe reduction of end tidal CO₂ (EtCO₂), hypotension and loss of arterial waveform, as well as cardiovascular rhythms associated with CPR, such as asystole, ventricular fibrillation and pulseless ventricular tachycardia. Often, CPR is initiated earlier in those who are anaesthetised and is associated with higher survival rates, likely due to the rapid response, presence of monitoring and previously established venous and airway access.

Basic life support (BLS) encompasses airway management, ventilation and chest compressions, forming the foundation of effective cardiopulmonary resuscitation (CPR). BLS is performed in 2-min cycles.

Advanced life support (ALS) involves pharmacologic interventions and advanced monitoring in addition to BLS to address the underlying causes of CPA and support ROSC. Drug dosing is available in Table 1.

Effective CPR in neonatal foals hinges on prompt recognition of CPA, initiation of BLS measures, including airway management, ventilation and chest compressions, followed by ALS interventions tailored to the foal's specific needs. Adherence to current RECOVER guidelines and continuous monitoring can enhance the likelihood of ROSC and improve survival outcomes. Ongoing research and training are crucial for refining resuscitation techniques and protocols in equine neonatology.

K. Varner: Writing – original draft; writing – review and editing. H. Roessner: Writing – original draft; writing – review and editing.

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The authors have no conflict of interest to report.

Not required for this clinical commentary.