title: Risk of postoperative complications in chronic obstructive lung diseases patients considered fit for lung cancer surgery: beyond oxygen consumption.
abstract: OBJECTIVE
  Patients with poor lung function usually undergo cardiopulmonary exercise testing (CPET) and those with a predicted postoperative maximal oxygen consumption (VO2max) of >10 ml/kg/min undergo lung resection surgery and still some complications are observed. We aimed to determine other parameters beyond VO2able to predict postoperative complications in patients undergoing lung resection surgery.
  
  
  METHODS
  This is an observational study with longitudinal follow-up. Patients with forced expiratory volume in 1 second (FEV1) or diffusing capacity for carbon monoxide of <40% underwent CPET and those with VO2max of >10 ml/kg/min were considered fit for surgery. Patients were followed up prospectively for 12 months and postoperative complications and survival were recorded. Physiological parameters obtained during CPET and pulmonary function tests were analysed.
  
  
  RESULTS
  Eighty-three chronic obstructive pulmonary disease (COPD) patients were evaluated for surgery between 2010 and 2015. Twenty-four patients were considered unfit for surgery and received an alternative therapy. Fifty-five patients had a VO2max of >10 ml/kg/min and underwent lung surgery. Among them, 4% died and 41% developed complications postoperatively. Baseline minute ventilation to carbon dioxide output (VE/VCO2) slope was significantly higher among those who developed postoperative complications or died (P = 0.047). Furthermore, VE/VCO2slope of >35 (at maximal exercise) was the single parameter most strongly associated with the probability of mortality and postoperative complications (hazard ratio 5.14) with a survival probability of 40% after 1 year of follow-up. In a multivariable model, VO2, VE/VCO2slope of >35 and work load were independently associated with the probability of having an event.
  
  
  CONCLUSIONS
  VO2is not the unique parameter to consider when CPET is performed to evaluate the postoperative risk of lung cancer surgery in COPD patients. The signs of ventilatory inefficiency such as VE/VCO2slope predict complications better than VO2does.
authors.affiliation: Department of Respiratory Medicine, Hospital Universitario Son Espases-IdISPa, Palma de Mallorca, Spain.|Chest Diseases Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: Hanaa
authors.initials: H
authors.lastname: Shafiek
authors.affiliation: Department of Respiratory Medicine, Hospital Universitario Son Espases-IdISPa, Palma de Mallorca, Spain.|Ciber de Enfermedades Respiratorias (Ciberes), Madrid, Spain.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Valera
authors.affiliation: Department of Respiratory Medicine, Hospital Universitario Son Espases-IdISPa, Palma de Mallorca, Spain.|Ciber de Enfermedades Respiratorias (Ciberes), Madrid, Spain.
authors.forename: Bernat
authors.initials: B
authors.lastname: Togores
authors.affiliation: Department of Thoracic Surgery, Hospital Universitario Son Espases, Palma de Mallorca, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Torrecilla
authors.affiliation: Department of Respiratory Medicine, Hospital Universitario Son Espases-IdISPa, Palma de Mallorca, Spain.|Ciber de Enfermedades Respiratorias (Ciberes), Madrid, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Sauleda
authors.affiliation: Department of Respiratory Medicine, Hospital Universitario Son Espases-IdISPa, Palma de Mallorca, Spain borja.cosio@ssib.es.|Ciber de Enfermedades Respiratorias (Ciberes), Madrid, Spain.
authors.forename: Borja G
authors.initials: BG
authors.lastname: Cosío
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications* / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011183:Postoperative Complications / Q000209:etiology*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012307:Risk Factors
keywords: Lung cancer; Minute ventilation; Operability; Oxygen consumption; Postoperative complications