Preanaesthetic blood tests in cats and dogs older than 8 years: anaesthetists’ prediction and peri-anaesthetic changes

Published:August 03, 2021DOI:



      To evaluate the anaesthetist’s ability to predict abnormalities in preanaesthetic blood test results obtained from cats and dogs older than 8 years and to describe the impact of these preanaesthetic blood test results on the American Society Anesthesiologists (ASA) physical status classification, anaesthetic protocol and procedures.

      Study design

      Observational, prospective, clinical multi-centre study.


      A total of 333 cats and dogs.


      After a clinical examination and review of the animal´s clinical history the anaesthetist completed the first part of a set of questions including ASA status and anticipated abnormalities in blood tests. After this, blood results were presented, and the anaesthetist completed the second part of the set of questions, including changes in ASA status or anaesthetic protocol, and procedure delay or cancellation. Preanaesthetic blood tests included: haematocrit, total proteins, electrolytes, glucose, lactate, urea and creatinine. Examiners were classified as senior clinicians, clinicians, anaesthesia residents or nurses, and interns. For statistical analysis, the chi-square test was used. A p value < 0.05 was considered significant.


      The ASA status increased in three dogs and one cat (1.2%); in two of them abnormalities were not expected by the examiner. The anaesthetic protocol changed in seven animals (2.1%); the most common change related to fluid therapy. Anaesthesia was delayed in two dogs (0.6%) to administer intravenous fluid therapy. No cases were cancelled. Abnormalities were more commonly found [37 out of 58 assessments (approximately 64%)] when the anaesthetist predicted them compared to when they were unexpected [49 of 275 assessments (approximately 18%); p < 0.001].

      Conclusions and clinical relevance

      Routine non-targeted blood tests in cats and dogs older than 8 years led to few changes in the anaesthetic management, and anaesthetists correctly predicted blood test results in most cases.


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


      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


        • Alef M.
        • von Praun F.
        • Oechtering G.
        Is routine pre-anaesthetic haematological and biochemical screening justified in dogs?.
        Vet Anaesth Analg. 2008; 35: 132-140
        • Apfelbaum J.L.
        • Connis R.T.
        • Nickinovich D.G.
        • et al.
        Practice advisory for preanesthesia evaluation: an updated report by the American Society of Anesthesiologists Task Force on Preanesthesia Evaluation.
        Anesthesiology. 2012; 116: 522-538
        • Bille C.
        • Auvigne V.
        • Bomassi E.
        • et al.
        An evidence-based medicine approach to small animal anaesthetic mortality in a referral practice: the influence of initiating three recommendations on subsequent anaesthetic deaths.
        Vet Anaesth Analg. 2014; 41: 249-258
        • Bille C.
        • Auvigne V.
        • Libermann S.
        • et al.
        Risk of anaesthetic mortality in dogs and cats: an observational cohort study of 3546 cases.
        Vet Anaesth Analg. 2012; 39: 59-68
        • Brodbelt D.C.
        The confidential enquiry into perioperative small animal fatalities.
        (PhD thesis) Royal Veterinary College, University of London, and Animal Health Trust, 2006: 173-175
        • Brodbelt D.C.
        • Pfeiffer D.U.
        • Young L.E.
        • et al.
        Risk factors for anaesthetic-related death in cats: results from the confidential enquiry into perioperative small animal fatalities (CEPSAF).
        Br J Anaesth. 2007; 99: 617-623
        • Clarke C.K.
        • Trim C.M.
        • Hall L.W.
        Veterinary Anaesthesia.
        Saunders, London, UK2014: 11-13
        • Davies M.
        • Kawaguchi S.
        Pregeneral anaesthetic blood screening of dogs and cats attending a UK practice.
        Vet Rec. 2014; 174: 506
        • Epstein M.
        • Kuehn N.F.
        • Landsberg G.
        • et al.
        AAHA senior care guidelines for dogs and cats.
        J Am Anim Hosp Assoc. 2005; 41: 81-91
        • Gil L.
        • Redondo J.I.
        Canine anaesthetic death in Spain: a multicentre prospective cohort study of 2012 cases.
        Vet Anaesth Analg. 2013; 40: e57-e67
        • Grubb T.
        • Sager J.
        • Gaynor J.S.
        • et al.
        2020 AAHA anesthesia and monitoring guidelines for dogs and cats.
        J Am Anim Hosp Assoc. 2020; 56: 59-82
        • Itami T.
        • Aida H.
        • Asakawa M.
        • et al.
        Association between preoperative characteristics and risk of anaesthesia-related death in dogs in small-animal referral hospitals in Japan.
        Vet Anaesth Analg. 2017; 44: 461-472
        • Joubert K.E.
        Pre-anaesthetic screening of geriatric dogs.
        J S Afr Vet Assoc. 2007; 78: 31-35
        • 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
        • Mayhew D.
        • Mendonca V.
        • Murthy B.V.S.
        A review of ASA physical status — historical perspectives and modern developments.
        Anaesthesia. 2019; 74: 373-379
        • McMillan M.
        • Brearley J.
        Assessment of the variation in American Society of Anesthesiologists Physical Status Classification assignment in small animal anaesthesia.
        Vet Anaesth Analg. 2013; 40: 229-236
        • Mitchell K.
        • Barletta M.
        • Quandt J.
        • et al.
        Effect of routine pre-anesthetic laboratory screening on pre-operative anesthesia-related decision-making in healthy dogs.
        Can Vet J. 2018; 59: 773-778
        • National Institute for Health and Care Excellence
        Routine preoperative tests for elective surgery.
        BJU Int. 2018; 121: 12-16
        • Robertson S.A.
        • Gogolski S.M.
        • Pascoe P.
        • et al.
        AAFP feline anesthesia guidelines.
        J Feline Med Surg. 2018; 20: 602-634
        • Verma R.
        • Wee M.Y.K.
        • Hartle A.
        • et al.
        Pre-operative Assessment and Patient Preparation.
        2010 (The Role of the Anaesthetist)
        • Warne L.N.
        • Bauquier S.H.
        • Pengelly J.
        • et al.
        Standards of care Anaesthesia guidelines for dogs and cats.
        Aust Vet J. 2018; 96: 413-427