The effects of nitrous oxide on left ventricular systolic and diastolic performance before and after cardiopulmonary bypass: evaluation by computer-assisted two-dimensional and Doppler echocardiography in patients undergoing coronary artery surgery.
We investigated the effects of nitrous oxide (N2O) on central hemodynamics and left ventricular systolic and diastolic function in 25 patients undergoing coronary artery bypass surgery. All patients were receiving beta-blockers and had good left ventricular function. Global and regional systolic left ventricular performance and diastolic function were determined by computer-assisted analysis of transesophageal echocardiographic (TEE) images, and mitral Doppler flow profiles, respectively. The patients were anesthetized with fentanyl and ventilated with oxygen in air. Hemodynamic and TEE measurements were obtained before and after the introduction of N2O in oxygen (60%/40%), before and after cardiopulmonary bypass (CPB). N2O reduced mean arterial pressure, heart rate, stroke volume, and cardiac output both before and after CPB. Left ventricular global area ejection fraction (GAEF) was not changed by the introduction of N2O, either before or after CPB. N2O induced a significant change in regional wall motion after, but not before CPB, as assessed by the relationship between segmental area ejection fraction (SAEF) and GAEF. Analysis of the mitral flow profile indicated an increase in early diastolic relaxation in the pre-CPB period after introduction of N2O, that was absent in the post-CPB period. We conclude that N2O induces regional wall motion abnormalities and possibly diastolic dysfunction post-CPB.
Houltz
E
E
Department of Anesthesia and Intensive Care, Sahlgrenska University Hospital, Gothenburg, Sweden.
Caidahl
K
K
Hellström
A
A
Gustavsson
T
T
Milocco
I
I
Ricksten
S E
SE
D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D003971:Diastole / Q000187:drug effects; D004452:Echocardiography; D015150:Echocardiography, Doppler; D017548:Echocardiography, Transesophageal; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008943:Mitral Valve / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D017682:Myocardial Stunning / Q000503:physiopathology; D009609:Nitrous Oxide / Q000494:pharmacology*; D013318:Stroke Volume / Q000187:drug effects; D013599:Systole / Q000187:drug effects; D016277:Ventricular Function, Left / Q000187:drug effects*
D009609:Nitrous Oxide