Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Influence of the anaesthetist´s perception on the evaluation of recovery quality in horses undergoing general anaesthesia.
Abstract: In horses, anaesthetic recovery is evaluated using subjective scales. Previous studies examined the influence of scale type and evaluator-related factors but the impact of operator perception (unconscious bias) has received limited attention. Unassigned: To analyse the influence of operator perception on recovery scoring. Unassigned: Anaesthetic recoveries at an equine hospital (May 2019-May 2023) were assessed in real time (RT) by attending anaesthetists and retrospectively using video recordings (VR) by a single evaluator. Horses aged 1 - 21 years undergoing a single anesthetic procedure with complete video recordings were included. Recovery quality was scored using a simple scale (SS; 1 = excellent to 5 = dangerous) and a detailed scale (DS; 0 = very violent to 5 = no ataxia). RT and VR were compared using the Wilcoxon signed-rank test. A secondary analysis included only cases evaluated by the same anaesthetist in both conditions. Exploratory analyses assessed influences of time of day, procedure, anaesthesia duration, number of standing attempts and grouped recovery categories. Analyses were performed using SPSS (IBM) (p < 0.05). Unassigned: Of 262 recoveries, 154 met inclusion criteria. VR scores were significantly worse than RT assessment for both scales [SS: 2 (IQR: 1); DS: 4 (IQR: 1)], including same-evaluator cases [SS: 2 (IQR: 2); DS: 4 (IQR: 1)]. Discrepancies persisted across most subgroups but were not observed in unsatisfactory recoveries, or for DS scores during nighttime or horses presenting ≥3 standing attempts. Unassigned: Anaesthetists tend to assign more favourable scores when evaluating their own patients in RT, suggesting an optimism bias.
© 2026 The Authors.
Publication Date: 2026-10-15 PubMed ID: 42959803PubMed Central: PMC13718388DOI: 10.1016/j.vas.2026.100899Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
Overview
- This study investigated how anesthetists’ perceptions influence their assessment of recovery quality in horses undergoing general anesthesia.
- It compared real-time scoring by attending anesthetists with retrospective scoring based on video recordings to determine if unconscious optimism bias affects evaluations.
Background
- In equine medicine, recovery after general anesthesia is critically important and is often assessed subjectively using scoring scales.
- Previous research has examined how the type of scale and different evaluators impact scoring but has overlooked the effect of the anesthetist’s own perception or unconscious bias.
- The study aims to clarify whether the anesthetist’s familiarity and direct involvement with the patient might cause them to rate recoveries more positively compared to an independent video-based review.
Methodology
- Setting: Evaluations took place at an equine hospital over a four-year period (May 2019 – May 2023).
- Participants: 154 horses aged between 1 and 21 years, each undergoing a single anesthesia procedure, with complete video recordings of their recovery.
- Evaluation Approach:
- Real-time (RT) recovery scoring conducted by the attending anesthetist during the recovery process.
- Retrospective video review (VR) scoring performed later by a single independent evaluator who was blinded to the original RT scores.
- Scoring Scales Used:
- Simple Scale (SS): from 1 (excellent recovery) to 5 (dangerous recovery).
- Detailed Scale (DS): from 0 (very violent recovery) to 5 (no ataxia or instability).
- Statistical analysis:
- Wilcoxon signed-rank test used to compare RT and VR scores.
- Secondary analysis for cases scored by the same anesthetist in both RT and VR conditions to minimize evaluator variability.
- Additional exploratory analyses examined the influence of factors such as time of day, type of procedure, anesthesia duration, and number of standing attempts during recovery.
- Significance threshold set at p < 0.05.
Key Findings
- Overall, retrospective video-based scores (VR) were significantly worse than real-time scores (RT) on both the simple and detailed scales.
- This discrepancy persisted even when only comparing scores from the same anesthetist in both conditions, suggesting the observed differences are due to bias rather than evaluator differences.
- The optimistic bias (assigning more favorable scores in RT) was consistent across most subgroups analyzed, including different procedures and anesthesia durations.
- No significant discrepancies were found in cases where recovery was unsatisfactory or in detailed scale scores during nighttime or in horses that required three or more standing attempts before fully recovering.
- This suggests that anesthetists are less likely to underestimate poor recoveries or challenging cases but more likely to overestimate quality in otherwise routine or smoother recoveries.
Conclusions and Implications
- Anesthetists evaluating their own patients in real time tend to rate recoveries more positively compared to a blinded, retrospective review.
- This optimism bias may impact clinical audits, research data, and quality assurance processes by underestimating recovery risks if only RT evaluations are used.
- Using objective, blinded video assessments alongside RT scoring could improve accuracy and reduce potential biases in recovery quality evaluation.
- Understanding and accounting for this bias is important for better decision-making and improving anesthesia and recovery protocols in equine veterinary care.
Cite This Article
APA
Benavente-Sánchez L, Villalba-Díez M, Jaen-Garcia C, Santiago-Llorente I, Villalba-Orero M.
(2026).
Influence of the anaesthetist´s perception on the evaluation of recovery quality in horses undergoing general anaesthesia.
Vet Anim Sci, 34, 100899.
https://doi.org/10.1016/j.vas.2026.100899 Publication
Researcher Affiliations
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, Spain.
- Complutense Veterinary Teaching Hospital, Universidad Complutense de Madrid, Spain.
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, Spain.
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, Spain.
- Complutense Veterinary Teaching Hospital, Universidad Complutense de Madrid, Spain.
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, Spain.
- Complutense Veterinary Teaching Hospital, Universidad Complutense de Madrid, Spain.
Conflict of Interest Statement
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Maria Villalba-Orero reports financial support and article publishing charges were provided by Complutense University of Madrid. Marta Villalba Orero reports financial support was provided by Spain Ministry of Science Innovation and Universities. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References
This article includes 22 references
- Althubaiti A. Information bias in health research: Definition, pitfalls, and adjustment methods.. Journal of Multidisciplinary Healthcare 2016;9:211.
- Aranda López King A, Juristo Juzgado N, Dieste Tubio O. Evidence of the presence of bias in subjective metrics: Analysis within a family of experiments. EASE ’14: Proceedings of the 18th International Conference on Evaluation and Assessment in Software Engineering 2014; p. 453.
- Clark-Price S.C., Lascola K.M., Carter J.E., Da Cunha A.F., Donaldson L.L., Doherty T.J., Hofmeister E.H., Keating S.C.J., Mama K.R., Mason D.E., Posner L.P., Sano H., Seddighi R., Shih A.C., Weil A.B., Schaeffer D.J.. Assessment of agreement among diplomates of the American College of Veterinary Anesthesia and Analgesia for scoring the recovery of horses from anesthesia by use of subjective grading scales and development of a system for evaluation of the recovery of horses from anesthesia by use of accelerometry. Manuel Martin-Flores mv 2017;78(6) Number.
- Clark-Price S.C., Posner L.P., Gleed R.D.. Recovery of horses from general anesthesia in a darkened or illuminated recovery stall. Veterinary Anaesthesia and Analgesia 2008;35(6):473–479.
- Donaldson L.L., Dunlop G.S., Holland M.S., Burton B.A.. The recovery of horses from inhalant anesthesia: A comparison of halothane and isoflurane. Veterinary Surgery : VS 2000;29(1):92–101.
- Dugdale A.H., Taylor P.M.. Equine anaesthesia-associated mortality: Where are we now?. Veterinary Anaesthesia and Analgesia 2016;43(3):242–255.
- Farmer E., Chase-Topping M., Lawson H., Clutton R.E.. Factors affecting the perception of recovery quality in horses after anaesthesia. Equine Veterinary Journal 2014;46(3):328–332.
- Gerhard T.. Bias: Considerations for research practice. American Journal of Health-System Pharmacy 2008;65(22):2159–2168.
- Gozalo-Marcilla M., Bettschart-Wolfensberger R., Johnston M., Taylor P.M., Redondo J.I.. Data collection for the fourth multicentre confidential enquiry of perioperative fatalities (CEPEF4) study: New technology and preliminary results. Animals 2021;11(9):2549.
- Grimes D.A., Schulz K.F.. Bias and causal associations in observational research. Lancet (London, England) 2002;359(9302):248–252.
- Holman L., Head M.L., Lanfear R., Jennions M.D.. Evidence of experimental bias in the life sciences: Why we need blind data recording. PLOS Biology 2015;13(7).
- Hubbell J.A.E.. Recovery from anaesthesia in horses. Equine Veterinary Education 1999;11(3):160–167.
- Johnston G., Eastment J., Wood J., Taylor P.. The confidential enquiry into perioperative equine fatalities (CEPEF): Mortality results of phases 1 and 2. Veterinary Anaesthesia and Analgesia 2002;29(4):159–170.
- Laurenza C., Ansart L., Portier K.. Risk factors of anesthesia-related mortality and morbidity in one equine hospital: A retrospective study on 1161 cases undergoing elective or emergency surgeries. Frontiers in Veterinary Science 2020;6.
- Leichsenring F., Abbass A., Hilsenroth M.J., Leweke F., Luyten P., Keefe J.R., Midgley N., Rabung S., Salzer S., Steinert C.. Biases in research: Risk factors for non-replicability in psychotherapy and pharmacotherapy research. Psychological Medicine 2017;47(6):1000–1011.
- Pollock NW. Managing bias in research. 31(1):1–2.
- Santiago-Llorente I, López-San Román FJ, Villalba-Orero M. Demographic, preoperative and anaesthesia-related risk factors for unsatisfactory recovery quality in horses undergoing emergency abdominal surgery. Veterinary Anaesthesia and Analgesia 2021;48(6):882–890.
- Scarabelli S, Rioja E. Retrospective evaluation of correlation and agreement between two recovery scoring systems in horses. The Veterinary Record 2018;182(6):169.
- Suthers JM, Christley RM, Clutton RE. Quantitative and qualitative comparison of three scoring systems for assessing recovery quality after general anaesthesia in horses. Veterinary Anaesthesia and Analgesia 2011;38(4):352–362.
- Vettorato E, Chase-Topping ME, Clutton RE. A comparison of four systems for scoring recovery quality after general anaesthesia in horses. Equine Veterinary Journal 2010;42(5):400–406.
- Wagner AE, Mama KR, Steffey EP, Hellyer PW. A comparison of equine recovery characteristics after isoflurane or isoflurane followed by a xylazine–ketamine infusion. Veterinary Anaesthesia and Analgesia 2008;35(2):154–160.
- Young SS, Taylor PM. Factors influencing the outcome of equine anaesthesia: A review of 1314 cases. Equine Veterinary Journal 1993;25(2):147–151.
Citations
This article has been cited 0 times.Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
