title: An alternative method for predicting the risk of postoperative complications in lung resection.
abstract: OBJECTIVE
  The aims of this study were to design a best fit linear regression model to estimate VO2max (estimated VO2) and to compare the ability of VO2 values (measured and estimated) predicting cardiorespiratory complications in a series of patients undergoing lung resection for lung cancer.
  
  
  METHODS
  This was a prospective, observational study performed in 83 patients. Variables analyzed were: demographic characteristics, comorbidity, body mass index (BMI), FEV1%, FVC%, diffusion capacity (DLCO%), mean daily distance walked in kilometers, VO2max measured by cardio-pulmonary exercise test (CPET) and postoperative complications. Descriptive and comparative statistical analysis of the variables was performed using the Mann-Whitney test for categorical variables and the Student's t-test for continuous variables. A new linear regression model was designed, where the dependent variable (measured VO2max) was estimated by the distance, DLCO% and age, resulting in the estimated VO2. The predictive power of the measured and estimated consumption was analyzed using the Student's t-test, grouping by the occurrence or absence of cardiorespiratory complications.
  
  
  RESULTS
  Both groups were homogeneous for age, sex, BMI, FEV1%, DLCO%, comorbidity, type of resection performed and mean distance walked per day. Estimated VO2 and measured VO2 were normally distributed (K-Smirnov test, P>.32). VO2 means estimated by the model (age, DLCO% and mean distance walked per day) were significantly different between patients with and without complications (Student's t test, P=.037) compared with measured VO2 values, which did not differentiate groups (Student's t test, P=.42).
  
  
  CONCLUSIONS
  The VO2max estimated by the model is more predictive in this case series than the VO2max measured during a standard exercise test.
authors: Servicio de Anestesiología, Hospital Universitario de Salamanca, Salamanca, España.
authors: Maria del Carmen
authors: Mdel C
authors: Vargas Fajardo
authors: Servicio de Cirugía Torácica, Hospital Universitario de Salamanca, IBSAL, Salamanca, España. Electronic address: nuria.novoa@usal.es.
authors: Nuria Maria
authors: NM
authors: Novoa Valentín
authors: Servicio de Cirugía Torácica, Hospital Universitario de Salamanca, IBSAL, Salamanca, España.
authors: Marcelo Fernando
authors: MF
authors: Jiménez López
authors: Servicio de Neumología, Unidad de Pruebas Funcionales Respiratorias, Hospital Universitario de Salamanca, Salamanca, España.
authors: Jacinto
authors: J
authors: Ramos Gonzalez
authors: Servicio de Cirugía Torácica, Hospital Universitario de Salamanca, IBSAL, Salamanca, España.
authors: Gonzalo
authors: G
authors: Varela Simó
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015897:Comorbidity; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011013:Pneumonectomy; D011183:Postoperative Complications / Q000209:etiology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011653:Pulmonary Diffusing Capacity; D018570:Risk Assessment; D014797:Vital Capacity; D016138:Walking
keywords: Complicaciones postoperatorias; Lung resection; Oxygen consumption; Pedometer; Podómetro; Postoperative complications; Prueba de esfuerzo; Resección pulmonar; Riesgo quirúrgico; Surgical risk; VO(2); VO(2max)