title: Gas exchange and pulmonary hemodynamics during lung resection in patients at increased risk: relationship with preoperative exercise testing.
abstract: OBJECTIVE
  To evaluate the intraoperative evolution of patients with COPD during lung resection and to test whether exercise testing could be helpful in the prediction of the intraoperative course.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  Forty patients (mean [+/- SD] age, 65 +/- 9 years) with COPD (ie, FEV(1), 55 +/- 11% of predicted) and resectable lung neoplasms.
  
  
  METHODS
  Preoperatively, pulmonary function testing, quantitative lung perfusion scanning, and exercise performance testing were administered. Intraoperatively, pulmonary, hemodynamic, and blood gas measurements were performed at five stages, including periods of two-lung ventilation (TLV) and periods of one-lung ventilation (OLV).
  
  
  RESULTS
  During OLV, compared with TLV, the PaO(2)/fraction of inspired oxygen (FIO(2)) ratio decreased from 458 +/- 120 to 248 +/- 131 mm Hg (p < 0.05), whereas pulmonary artery pressure (PAP) increased from 18 +/- 5 to 23 +/- 5 mm Hg (p < 0.05). Cardiac output (t) also increased from 4.0 +/- 1.2 to 5.1 +/- 1.9 L/min (p < 0.05), yielding to a higher mixed venous PO(2). Both PaO(2) and t during OLV were significantly lower in patients who had undergone right thoracotomies compared with those who had undergone left thoracotomies. The PaO(2)/FIO(2) ratio during OLV correlated with the PaO(2) during exercise (r = 0.39; p = 0.01) and with the perfusion of the non-neoplastic lung (r = 0.44; p = 0.005).
  
  
  CONCLUSIONS
  In COPD patients, OLV leads to a significant derangement of gas exchange, which is more pronounced in right thoracotomies. Preoperative measurement of PaO(2) during exercise and the distribution of perfusion by lung scan might be useful to identify those patients who are at the greatest risk of abnormal gas exchange during lung resections.
authors.affiliation: Serveis de Pneumologia i Allèrgia Respiratòria, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Ribas
authors.forename: M J
authors.initials: MJ
authors.lastname: Jiménez
authors.forename: J A
authors.initials: JA
authors.lastname: Barberà
authors.forename: J
authors.initials: J
authors.lastname: Roca
authors.forename: C
authors.initials: C
authors.lastname: Gomar
authors.forename: E
authors.initials: E
authors.lastname: Canalís
authors.forename: R
authors.initials: R
authors.lastname: Rodriguez-Roisin
mesh_terms: D000368:Aged; D000075202:Contraindications; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008168:Lung / Q000502:physiology; D008173:Lung Diseases, Obstructive / Q000209:etiology* / Q000503:physiopathology*; D008175:Lung Neoplasms / Q000150:complications* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D015656:Respiratory Mechanics; D018570:Risk Assessment; D013908:Thoracotomy