Effects of phenylephrine or volume loading on right ventricular function in patients undergoing myocardial...

The acute effects of phenylephrine (PHE) administration or intravascular volume loading on right ventricular (RV) function were examined in 34 patients undergoing elective coronary artery surgery. After anesthetic induction with sufentanil and midazolam, 20 patients received PHE to treat hypotension and increase systemic arterial pressure 20% above baseline values. PHE effectively restored arterial pressure without changing stroke index (SI), although RV ejection fraction (RVEF) declined (41.3% to 37.6%) with concomitant increases in RV end-diastolic volume index (RVEDVI) (86.3 to 97.5 mL/m2) and RV end-systolic volume index (51.8 to 63.4 mL/m2). In the first 6 to 8 hours after surgery, 18 patients received intravascular volume expansion with 5% albumin when the clinical perfusion state was inadequate and accompanied by pulmonary artery occlusion pressure (PAOP) less than 15 mmHg and a hemoglobin level greater than 8 g/dL. Volume loading with 500 mL of albumin increased SI(27.0 to 31.8mL/m2), PAOP (12.2 to 15.4 mmHg) and RVEDVI (69.0 to 86.5 mL/m2), although RVEF declined (39.3% to 37.6%). Baseline values of RVEF and SI (but not PAOP or right atrial pressure [RAP]) were lower in 9 of 18 patients who exhibited declines in RVEF after volume loading, and RAP was a poor indicator of RVEDVI (r = 0.17). RVEDVI (but not RAP or PAOP) had significant correlation with SI during volume loading. There was no relationship between the presence of hemodynamically significant right coronary artery stenoses requiring revascularization or other perioperative factors with the response to PHE before revascularization or to volume loading after revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)