Hemodynamic changes with right lateral decubitus body positioning in the tilted porcine heart

Background. In beating-heart coronary surgical procedures, exposure of post erior vessels through sternotomy causes cardiac function to deteriorate. We hypothesized that turning the subject to the right lateral decubitus posit ion before cardiac retraction improves exposure of posterior vessels and pr eserves cardiac pump function on displacement. Methods. Eight 80-kg open-chest pigs were instrumented with catheter-tip ma nometers. After a stepwise 60-degree turn to the right lateral decubitus po sition of the body, the heart was retracted anteriorly to 90 degrees with a suction stabilizer. Results. Right lateral body positioning caused an approximately 45-degree r ight deviation of the apex, thereby exposing the left atrial groove. Stroke volume, mean arterial pressure, right atrial pressure, and right ventricul ar end-diastolic pressure increased to 106% +/- 5% (mean +/- standard error of the mean, p = 0.31), 106% +/- 3% (p = 0.01), 129% 8% (p = 0.001), and 1 71% +/- 14% (p = 0.002), respectively, compared with control values. In con trast, left atrial pressure decreased to 73% +/- 6% (p = 0.007), whereas le ft ventricular preload remained unchanged (110% +/- 8%, p = 0.26). Addition al anterior displacement to 90 degrees fully exposed the posterior vessels, and stroke volume decreased to 90% +/- 3% (p = 0.01) and mean arterial pre ssure to 93% +/- 5% (p = 0.07) at the expense of further increased right ve ntricular preload (256% +/- 28%, p < 0.001). Conclusions. By placing the subject in the right lateral decubitus position , exposure through sternotomy of posterior vessels in the beating porcine h eart was facilitated while mean arterial pressure was maintained. (C) 2001 by The Society of Thoracic Surgeons.