Normobaric hyperoxia reduces cardiac index in patients after coronary artery bypass surgery.
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.
Harten
Johann M
JM
Department of Anaesthesia, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom. jharten@doctors.org.uk
Anderson
Keith J
KJ
Kinsella
John
J
Higgins
Michael J
MJ
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
D010100:Oxygen