title: Validation of preoperative cardiopulmonary exercise testing-derived variables to predict in-hospital morbidity after major colorectal surgery.
abstract: BACKGROUND
  In single-centre studies, postoperative complications are associated with reduced fitness. This study explored the relationship between cardiorespiratory fitness variables derived by cardiopulmonary exercise testing (CPET) and in-hospital morbidity after major elective colorectal surgery.
  
  
  METHODS
  Patients underwent preoperative CPET with recording of in-hospital morbidity. Receiver operating characteristic (ROC) curves and logistic regression were used to assess the relationship between CPET variables and postoperative morbidity.
  
  
  RESULTS
  Seven hundred and three patients from six centres in the UK were available for analysis (428 men, 275 women). ROC curve analysis of oxygen uptake at estimated lactate threshold (V˙o2at θ^L) and at peak exercise (V˙o2peak) gave an area under the ROC curve (AUROC) of 0·79 (95 per cent c.i. 0·76 to 0·83; P < 0·001; cut-off 11·1 ml per kg per min) and 0·77 (0·72 to 0·82; P < 0·001; cut-off 18·2 ml per kg per min) respectively, indicating that they can identify patients at risk of postoperative morbidity. In a multivariable logistic regression model, selected CPET variables and body mass index (BMI) were associated significantly with increased odds of in-hospital morbidity (V˙o2at θ^L11·1 ml per kg per min or less: odds ratio (OR) 7·56, 95 per cent c.i. 4·44 to 12·86, P < 0·001; V˙o2peak18·2 ml per kg per min or less: OR 2·15, 1·01 to 4·57, P = 0·047; ventilatory equivalents for carbon dioxide at estimated lactate threshold (V˙E/V˙co2at θ^L) more than 30·9: OR 1·38, 1·00 to 1·89, P = 0·047); BMI exceeding 27 kg/m2: OR 1·05, 1·03 to 1·08, P < 0·001). A laparoscopic procedure was associated with a decreased odds of complications (OR 0·30, 0·02 to 0·44; P = 0·033). This model was able to discriminate between patients with, and without in-hospital morbidity (AUROC 0·83, 95 per cent c.i. 0·79 to 0·87). No adverse clinical events occurred during CPET across the six centres.
  
  
  CONCLUSIONS
  These data provide further evidence that variables derived from preoperative CPET can be used to assess risk before elective colorectal surgery.
authors.affiliation: Academic Unit of Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.|Critical Care Research Area, National Institute for Health Research Respiratory Biomedical Research Unit, Southampton, UK.|Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.|Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: West
authors.affiliation: Cancer Research UK Liverpool Cancer Trials Unit, Liverpool, UK.
authors.forename: R
authors.initials: R
authors.lastname: Asher
authors.affiliation: Department of Anaesthesia, Maidstone and Tunbridge Wells NHS Trust, Maidstone, UK.
authors.forename: M
authors.initials: M
authors.lastname: Browning
authors.affiliation: Directorate of Anaesthesia, Derriford Hospital, Plymouth, UK.|Plymouth University, Peninsula Schools of Medicine and Dentistry, Plymouth, UK.
authors.forename: G
authors.initials: G
authors.lastname: Minto
authors.affiliation: Department of Anaesthesia and Critical Care Medicine, Torbay Hospital, Torquay, UK.
authors.forename: M
authors.initials: M
authors.lastname: Swart
authors.affiliation: Sports Therapy, Physical Activity and Health Research Group, School of Sport and Exercise Sciences, University of Kent, Canterbury, UK.|Anaesthesia and Intensive Care Medicine, Medway Maritime Hospital, Gillingham, UK.
authors.forename: K
authors.initials: K
authors.lastname: Richardson
authors.affiliation: Department of Anaesthesia, University Hospital Crosshouse, Kilmarnock, UK.
authors.forename: L
authors.initials: L
authors.lastname: McGarrity
authors.affiliation: Critical Care Research Area, National Institute for Health Research Respiratory Biomedical Research Unit, Southampton, UK.|Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.|Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: S
authors.initials: S
authors.lastname: Jack
authors.affiliation: Critical Care Research Area, National Institute for Health Research Respiratory Biomedical Research Unit, Southampton, UK.|Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.|Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: M P W
authors.initials: MP
authors.lastname: Grocott
mesh_terms: D000328:Adult; D000368:Aged; D003107:Colorectal Surgery / Q000401:mortality*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011300:Preoperative Care / Q000379:methods; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods; D006113:United Kingdom