title: Normobaric hyperoxia reduces cardiac index in patients after coronary artery bypass surgery.
abstract: OBJECTIVE
  The purpose of this study was to assess the hemodynamic changes in response to normobaric hyperoxia in patients immediately after coronary artery bypass surgery.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Single-center university hospital.
  
  
  METHODS
  Patients immediately after coronary artery bypass surgery.
  
  
  METHODS
  Change of fractional inspired oxygen concentration from baseline (< or =0.60) to 1.0 and return to baseline.
  
  
  RESULTS
  Cardiovascular changes were assessed with a lithium dilution technique. Cardiac index decreased from 2.82 to 2.52 L/min/m2 (10.6%). Heart rate decreased from 85.9 to 82.5 beats/min (4.0%), and the systemic vascular resistance index increased from 1,858 to 2,304 dyne/s/cm5/m2 (24.1%). Stroke index or mean arterial pressure did not change significantly. On reducing the FIO2 from 1.0 to the baseline FIO2 , there was significant reversal of the previous changes in heart rate and systemic vascular resistance. Heart rate increased from 82.5 to 84.0 beats/min (1.8%), and the systemic vascular index decreased from 2304 to 1932 dyne/s/cm5/m2 (16.1%). The cardiac output did not return to baseline, and the mean arterial pressure decreased from 69.6 to 64.4 mmHg (7.6%).
  
  
  CONCLUSIONS
  Exposing patients after coronary artery surgery to hyperoxia induces significant hemodynamic changes.
authors.affiliation: Department of Anaesthesia, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom. jharten@doctors.org.uk
authors.forename: Johann M
authors.initials: JM
authors.lastname: Harten
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Anderson
authors.forename: John
authors.initials: J
authors.lastname: Kinsella
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Higgins
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D001026:Coronary Artery Bypass; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D014655:Vascular Resistance / Q000502:physiology
chemical_list: D010100:Oxygen