title: Patterns of changes in arterial PO2 during one-lung ventilation: a comparison between patients with severe pulmonary emphysema and patients with preserved lung function.
abstract: OBJECTIVE
  One-lung ventilation (OLV) during thoracoscopic surgery is associated with a significant decline in arterial PO(2) in patients with severe pulmonary emphysema and patients with preserved lung function. The authors hypothesized that patterns of arterial PO(2) changes are different in these 2 patient groups.
  
  
  METHODS
  Prospective nonrandomized study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Twenty-five patients undergoing thoracoscopic interventions: 16 with severe pulmonary emphysema and 9 patients without emphysema.
  
  
  METHODS
  Continuous arterial blood gas measurement (PaO(2), PaCO(2), pHa) during OLV of the left lung in left lateral position using the Paratrend 7 blood gas monitoring system (PT7; Pfizer Hospital Products Group, High Wycombe, UK).
  
  
  RESULTS
  The decrease of PaO(2) was delayed in patients with severe emphysema. Steady state (defined as DeltaPaO(2) <7.5 mmHg/min) was reached after 18 +/- 4 minutes compared with 11 +/- 3 minutes (mean +/- standard deviation) in patients with normal lung function (p = 0.0002). PaO(2) values at steady state were comparable (p = 0.49); the pattern of changes in PaO(2) for the first 15 minutes of left-sided OLV was significantly different between the groups (p = 0.0004). The difference of predicted versus measured PaO(2) at steady state was -48 +/- 160 mmHg for patients with emphysema and -51 +/- 60 mmHg for patients with normal lung function (p = 0.019).
  
  
  CONCLUSIONS
  During OLV, oxygenation is better preserved for a longer period of time in patients with severe pulmonary emphysema as compared with patients with normal lung function. In contrast to patients without emphysema, prediction of oxygenation during OLV for the individual patient with emphysema is unreliable because of large interindividual differences.
authors.affiliation: Institute of Anesthesiology, University Hospital Zurich, 8063 Zurich, Switzerland.
authors.forename: Schlomo V
authors.initials: SV
authors.lastname: Aschkenasy
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hofer
authors.forename: Marco P
authors.initials: MP
authors.lastname: Zalunardo
authors.forename: Michael
authors.initials: M
authors.lastname: Zaugg
authors.forename: Walter
authors.initials: W
authors.lastname: Weder
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Thomas
authors.initials: T
authors.lastname: Pasch
authors.forename: Andreas
authors.initials: A
authors.lastname: Zollinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000097:blood*; D012121:Respiration, Artificial / Q000379:methods*; D012720:Severity of Illness Index; D013906:Thoracoscopy