Risk of anesthesia-related complications in draft horses: a retrospective, single-center analysis

Published:December 11, 2022DOI:



      To report anesthetic-related complications and determine risks associated with anesthesia in draft horses.

      Study design

      Retrospective study.


      A total of 401 anesthetic records for draft horse breeds that underwent general anesthesia from January 2010 through December 2020 were reviewed; horses euthanized during general anesthesia were excluded.


      Demographics, perioperative drugs used, procedure type and duration, time to extubation, number of attempts to stand, use of sling in recovery and perioperative morbidity and mortality were investigated. Morbidity and mortality statistical evaluation included univariable logistic regression analysis and ordinal regression analysis.


      American Society of Anesthesiologists (ASA) status I–II, ASA III–V and total mortality rate for all cases was 0.69% (2/288), 6.19% (7/113) and 2.24% (9/401), respectively, with Belgian horses being overrepresented (6/9). Cardiac arrest occurred in six out of nine horses that died without euthanasia, and five out of six of these horses underwent colic surgery. Factors associated with increased mortality risk included ASA status of III–V, increased body weight, emergency status and horses presenting for colic. Hypotension, hypercarbia and hypoxemia occurred in 56% (224/401), 46% (186/401) and 14% (58/401) of horses, respectively. During recovery from anesthesia, lighter horses and horses undergoing shorter anesthetic procedures were more likely to be successful on the first or second attempt to stand and were less likely to require a sling in recovery.

      Conclusions and clinical relevance

      Draft horses undergoing general anesthesia had a higher mortality rate than previously reported for all types and breeds of horses.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Veterinary Anaesthesia and Analgesia
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Auckburally A.
        • Nyman G.
        Review of hypoxaemia in anaesthetized horses: predisposing factors, consequences and management.
        Vet Anaesth Analg. 2017; 44: 397-408
        • Bidwell L.A.
        • Bramlage L.R.
        • Rood W.A.
        Equine perioperative fatalities associated with general anaesthesia at a private practice – a retrospective case series.
        Vet Anaesth Analg. 2007; 34: 23-30
        • Dugdale A.H.A.
        • Taylor P.M.
        Equine anesthesia-associated mortality: where are we now?.
        Vet Anaesth Analg. 2016; 43: 242-255
        • Dugdale A.H.A.
        • Obhrai J.
        • Cripps P.J.
        Twenty years later: a single-centre, repeat retrospective analysis of equine perioperative mortality and investigation of recovery quality.
        Vet Anaesth Analg. 2016; 43: 171-178
        • Glade M.J.
        Effects of gestation, lactation, and maternal calcium intake on mechanical strength of equine bone.
        J Am Coll Nutr. 1993; 12: 372-377
        • Gleed R.
        • Short C.E.
        A retrospective study of the anesthetic management of adult draft horses.
        Vet Med Small Anim Clin. 1980; 75: 1409-1416
        • Grandy J.L.
        • Steffey E.P.
        • Hodgson D.S.
        • Woliner M.J.
        Arterial hypotension and the development of postanesthetic myopathy in halothane-anesthetized horses.
        Am J Vet Res. 1987; 48: 192-197
        • Johnston G.M.
        • Taylor P.M.
        • Holmes M.A.
        • Wood J.L.
        Confidential enquiry of perioperative equine fatalities (CEPEF-1): preliminary results.
        Equine Vet J. 1995; 27: 193-200
        • Johnston G.M.
        • Eastment J.K.
        • Wood J.L.N.
        • Taylor P.M.
        The confidential enquiry into perioperative equine fatalities (CEPEF): mortality results of Phases 1 and 2.
        Vet Anaesth Analg. 2002; 29: 159-170
        • Khanna A.K.
        • McDonell W.N.
        • Dyson D.H.
        • Taylor P.M.
        Cardiopulmonary effects of hypercapnia during controlled intermittent positive pressure ventilation in the horse.
        Can J Vet Res. 1995; 59: 213-221
        • Kraus B.M.
        • Parente E.J.
        • Tulleners E.P.
        Laryngoplasty with ventriculectomy or ventriculocordectomy in 104 draft horses (1992–2000).
        Vet Surg. 2003; 32: 530-538
        • Li G.
        • Warner M.
        • Lang B.H.
        • et al.
        Epidemiology of anesthesia-related mortality in the United States, 1999–2005.
        Anesthesiology. 2009; 110: 759-765
        • Mansel J.C.
        • Clutton R.E.
        The influence of body mass and thoracic dimensions on arterial oxygenation in anaesthetized horses and ponies.
        Vet Anaesth Analg. 2008; 35: 392-399
        • Matthews N.S.
        • Mohn T.J.
        • Yang M.
        • et al.
        Factors associated with anesthetic-related death in dogs and cats in primary care veterinary hospitals.
        J Am Vet Med Assoc. 2017; 250: 655-665
        • Moens Y.
        Arterial-alveolar carbon dioxide tension difference and alveolar dead space in halothane anaesthetised horses.
        Equine Vet J. 1989; 21: 282-284
        • Moens Y.
        • Lagerweij E.
        • Gootjes P.
        • Poortman J.
        Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape.
        Equine Vet J. 1995; 27: 110-116
        • Rothenbuhler R.
        • Hawkins J.F.
        • Adams S.B.
        • et al.
        Evaluation of surgical treatment for signs of acute abdominal pain in draft horses: 72 cases (1983–2002).
        J Am Vet Med Assoc. 2006; 10: 1546-1550
        • Young S.S.
        • Taylor P.M.
        Factors influencing the outcome of equine anesthesia: a review of 1,314 cases.
        Equine Vet J. 1993; 25: 147-151
        • Vermedal H.
        • Valverde A.
        • Sears W.
        Effect of anesthesia duration on the quality of recovery in horses undergoing elective and emergency surgeries using the same anesthetic protocol.
        Can J Vet Res. 2021; 85: 193-200