title: Resting End-Tidal Carbon Dioxide Predicts Respiratory Complications in Patients Undergoing Thoracic Surgical Procedures.
abstract: BACKGROUND
  Ventilatory efficiency (V˙e/V˙co2slope [minute ventilation to carbon dioxide output slope]) has been shown to predict morbidity and mortality in lung resection candidates. Patients with increased V˙e/V˙co2during exercise also exhibit an increased V˙e/V˙co2ratio and a decreased end-tidal CO2at rest. This study hypothesized that ventilatory values at rest predict respiratory complications and death in patients undergoing thoracic surgical procedures.
  
  
  METHODS
  Inclusion criteria for this retrospective, multicenter study were thoracotomy and cardiopulmonary exercise testing as part of routine preoperative assessment. Respiratory complications were assessed from the medical records (from the hospital stay or from the first 30 postoperative days). For comparisons, Student's t test or the Mann-Whitney U test was used. Logistic regression and receiver operating characteristic analyses were performed for evaluation of measurements associated with respiratory complications. Data are summarized as mean ± SD; p <0.05 is considered significant.
  
  
  RESULTS
  Seventy-six subjects were studied. Postoperatively, respiratory complications developed in 56 (74%) patients. Patients with postoperative respiratory complications had significantly lower resting tidal volume (0.8 ± 0.3 vs 0.9 ± 0.3L; p = 0.03), lower rest end-tidal CO2(28.1 ± 4.3vs 31.5 ± 4.2 mm Hg; p < 0.01), higher resting V˙e/V˙co2ratio (45.1 ± 7.1 vs 41.0 ± 6.4; p = 0.02), and higher V˙e/V˙co2slope (34.9 ± 6.4 vs 31.2 ± 4.3; p = 0.01). Logistic regression (age and sex adjusted) showed resting end-tidal CO2to be the best predictor of respiratory complications (odds ratio: 1.21; 95% confidence interval: 1.06 to 1.39; area under the curve: 0.77; p = 0.01).
  
  
  CONCLUSIONS
  Resting end-tidal CO2may identify patients at increased risk for postoperative respiratory complications of thoracic surgical procedures.
authors: Department of Respiratory Diseases, University Hospital Brno, Brno, Czech Republic; Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Kristian
authors: K
authors: Brat
authors: Department of Respiratory Medicine, Thomayer Hospital, Prague, Czech Republic.
authors: Zuzana
authors: Z
authors: Tothova
authors: Department of Respiratory Diseases, University Hospital Brno, Brno, Czech Republic; Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Zdenek
authors: Z
authors: Merta
authors: Department of Thoracic Surgery, Thomayer Hospital, Prague, Czech Republic.
authors: Alice
authors: A
authors: Taskova
authors: Faculty of Medicine, Masaryk University, Brno, Czech Republic; Department of Sports Medicine and Rehabilitation, St. Anne's University Hospital, Brno, Czech Republic; International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic.
authors: Pavel
authors: P
authors: Homolka
authors: Department of Respiratory Medicine, Thomayer Hospital, Prague, Czech Republic.
authors: Martina
authors: M
authors: Vasakova
authors: Department of Respiratory Diseases, University Hospital Brno, Brno, Czech Republic; Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors: Jana
authors: J
authors: Skrickova
authors: Department of Anesthesiology and Intensive Care, St. Anne's University Hospital, Brno, Czech Republic.
authors: Vladimir
authors: V
authors: Sramek
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors: Lyle J
authors: LJ
authors: Olson
authors: International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic; Department of Anesthesiology and Intensive Care, St. Anne's University Hospital, Brno, Czech Republic. Electronic address: ivan.cundrle@seznam.cz.
authors: Ivan
authors: I
authors: Cundrle
mesh_terms: D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism*; D018153:Czech Republic / Q000453:epidemiology; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008171:Lung Diseases / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology; D011379:Prognosis; D012146:Rest / Q000502:physiology*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D019616:Thoracic Surgical Procedures / Q000009:adverse effects*; D013990:Tidal Volume / Q000502:physiology*; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide