Trendelenburg position and passive leg raising do not significantly improve cardiopulmonary performance in the anesthetized patient with coronary artery disease

Abstract

The effects of the Trendelenburg (TREND) position and passive straight leg raising (PLR) on cardiopulmonary performance in 18 anesthetized patients undergoing myocardial revascularization were studied with a two-dimensional transesophageal echocardiography probe and a thermodilution right ventricular ejection fraction (RVEF) pulmonary artery catheter. The TREND position (at 20°) and PLR (at 60°) were studied in relation to the level-supine position in random order. At 3 min, the TREND caused significant (p < .05) decreases in heart rate (62 ± 9 to 58 ± 10 [SD] beat/min) and RVEF (0.48 ± 0.11 to 0.44 ± 0.10), and significant increases in mean arterial pressure (77 ± 11 to 82 ± 11 mm Hg), mean pulmonary artery pressure (16 ± 43 to 19 ± 5.5 mm Hg), wedge pressure (11 ± 4 to 13 ± 4 mm Hg), cardiac index (CI) (2.36 ± 0.79 to 2.52 ± 0.93 L/min.m²), right ventricular end-systolic volume index (44 ± 21 to 58 ± 21 ml/m²), right ventricular end-diastolic volume index (83 ± 24 to 102 ± 22 ml/m²), and shunt fraction (0.16 ± 0.06 to 0.19 ± 0.06). CVP and left ventricular areas did not change significantly. PLR had similar effects as the TREND position, except CI did not change significantly. Thus, the TREND and PLR resulted in minor hemodynamic improvement with right ventricular dilation, decreased RVEF, and impaired oxygenation in the anesthetized cardiac surgical patient. (Crit Care Med 1989: 17:313)