Rewarming hypovolemia after aortocoronary bypass surgery.
Coronary bypass performed with moderate systemic hypothermia (25 degrees C) and cold-potassium cardioplegia was associated with a fall and subsequent rise in core (pulmonary arterial) temperature. Serial hemodynamic measurements during rewarming and recovery revealed a decrease in cardiac index (CI) without a decrease in the left atrial pressure (LAP) of 17 patients recovering from uneventful coronary bypass surgery. Nuclear ventriculograms performed during rewarming demonstrated a decrease in left ventricular end-diastolic volume index (EDVI, calculated from the thermodilution stroke index divided by the nuclear ejection fraction) without a change in LAP. Volume loading during both mild hypothermia (35 +/- 5[SD]degrees C) and normothermia revealed that myocardial performance (the relation between CI and EDVI) was unchanged, but diastolic compliance (the relation between LAP and EDVI) decreased with rewarming. LAP was a poor indicator of left ventricular preload (EDVI) during rewarming, and volume loading was required to maintain preload and prevent hypoperfusion.
D016275:Atrial Function; D001794:Blood Pressure; D001810:Blood Volume; D001026:Coronary Artery Bypass; D003971:Diastole; D005260:Female; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics; D006358:Hot Temperature / Q000627:therapeutic use*; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D011182:Postoperative Care; D011651:Pulmonary Artery / Q000502:physiology*; D013318:Stroke Volume