The effect of cardiopulmonary bypass and inspired oxygen concentration on left ventricular contrast opacification with optison, a second-generation ultrasound contrast agent.
OBJECTIVE: To investigate the influence of cardiopulmonary bypass (CPB) and fraction of inspired oxygen (F(I)O(2)) on the contrast effect of Optison, a second-generation ultrasound contrast agent, in humans during coronary artery bypass graft (CABG) surgery with transesophageal echocardiography (TEE). DESIGN: Prospective, observational, repeated-measures design. SETTING: A single university hospital. PARTICIPANTS: Ten patients who underwent elective CABG surgery. INTERVENTIONS: A transgastric, midpapillary, short-axis view of the left ventricle was obtained with TEE in the conventional imaging mode. A central injection of 0.3 mL of Optison was administered at 4 stages: after induction of anesthesia at F(I)O(2) = 1.0 and F(I)O(2) = 0.43 +/- 0.02 and after protamine administration at F(I)O(2) = 1.0 and F(I)O(2) = 0.52 +/- 0.09. Background-corrected maximal pixel intensity (PImax(corr)) in the left ventricle was determined with videodensitometry. To estimate the magnitude of change in pixel intensities, point estimates of differences in PImax(corr) and their 95% and 99% confidence intervals were calculated after repeated measures analysis of variance. MEASUREMENTS AND MAIN RESULTS: Decreasing the F(I)O(2) from 1.0 to <1 did not alter PImax(corr) significantly before or after CPB (mean change = -4.2 and 0.8; SE = 2.0 and 1.9; p = 0.06 and 0.68). Values for PImax(corr) before and after CPB were not significantly different at either F(I)O(2) = 1.0 or F(I)O(2) <1 (mean change = -3.3 and 1.7; SE = 2.4 and 2.7; p = 0.26 and 0.54). Mean differences from initial values ranged from a 10% decrease to a 5% increase. CONCLUSION: In patients who undergo CABG surgery, the contrast opacification of Optison in the left ventricle is not changed by CPB or alterations in F(I)O(2) during intraoperative TEE. The application of Optison for enhancement of the endocardial border is not limited during cardiac surgery.
Dupont, FW; Drum, M; Fisher, AM; Aronson, S
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