Risk assessment in equine anesthesia: a first evaluation of the usability, utility and predictivity of the two-part CHARIOT.
Authors: Brumund Lisa, Wittenberg-Voges Liza, Rohn Karl, Kästner Sabine B R
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: CHARIOT Risk Assessment Tool for Equine Anaesthesia Predicting perioperative complications in equine anaesthesia remains challenging, yet accurate risk stratification could meaningfully improve patient outcomes and inform client discussions. Researchers evaluated three scoring systems—the American Society of Anaesthesiologists Physical Status scale adapted for horses (ASA-PS-Equine), a 10-part multifactorial rubric (10-RS), and their combination (CHARIOT)—across 300 horses undergoing general anaesthesia, tracking intra-operative and post-operative complications, recovery quality, and mortality over seven days using logistic regression and receiver operating characteristic curve analysis. Whilst all three tools demonstrated statistically significant associations with various intra-operative complications and recovery parameters, their predictive power for specific complications proved modest (area under curve 0.54–0.67), though all performed substantially better for overall mortality (0.75–0.80), with ASA-PS-Equine showing the strongest discriminatory ability. Inter-observer reliability was fair for the 10-RS (κ = 0.39) and moderate for ASA-PS-Equine (κ = 0.52), though clinicians rated CHARIOT assignment as quick and straightforward. For equine practitioners, these findings suggest that whilst current risk scores offer useful mortality prediction and should inform pre-operative planning and communication with owners, they cannot reliably predict individual intra- or post-operative complications, meaning clinical vigilance and individualised perioperative protocols remain essential rather than tools being viewed as definitive predictors.
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Practical Takeaways
- •Use ASA-PS-Equine scoring primarily to communicate mortality risk to clients and optimize perioperative management—do not rely on it to predict specific intra- or post-operative complications
- •Be aware that anesthetic risk scores have only moderate inter-observer reliability; standardized training and consistent application by the same assessor improves reliability for individual practices
- •While CHARIOT is quick and easy to implement clinically, recognize that current scoring systems cannot reliably predict which horses will experience specific perioperative complications—additional vigilance is required
Key Findings
- •ASA-PS-Equine showed highest discriminant ability for mortality prediction (AUC = 0.7970), significantly better than predicting intra-operative (AUC = 0.6093-0.6701) or post-operative complications (AUC = 0.5373-0.6194)
- •Inter-observer reliability was moderate for ASA-PS-Equine (κ = 0.52) and fair for 10-RS (κ = 0.39), indicating substantial variability between assessors
- •All three risk scoring systems (ASA-PS-Equine, 10-RS, and CHARIOT) provided useful mortality prediction but were ineffective at predicting specific intra- or post-anesthetic complications
- •CHARIOT was rated as predominantly easy and quick to use by assessors, supporting its practical application in clinical settings