Effects of Upright Posturing On Selected Physiologic Parameters at Twenty-Four Hours Post-Coronary Artery Bypass Surgery

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Human Performance and Recreation

First Advisor

Tommy Boone

Advisor Department

Human Performance and Recreation


The purpose of this study was to determine the effects of upright posturing (30$\sp\circ$ upright) for six hours immediately following surgery on selected physiologic parameters at twenty four hours post coronary artery bypass (CABG) surgery. The specific parameters were: oxygen consumption index (VO$\sb2$I), heart rate (HR), cardiac index (CI), stroke volume index (SVI), oxygen saturation (SaO$\sb2$), mixed venous oxygen saturation (SvO$\sb2$), mean arterial pressure (MAP), and systemic vascular resistance index (SVRI). Eight subjects were placed in a supine position (control group) for six hours and eight subjects were placed at 30$\sp\circ$ upright (treatment group) for six hours. At 24 hours post CABG surgery, selected hemodynamic measurements were taken. The data were analyzed using two-tailed t tests to determine the significant difference (p $<$ 0.05), if any, between two means. No significant difference were found in any of the data except CI where the control group demonstrated a CI of 3.01 L$\cdot$min$\cdot$m$\sp2$ and the treatment group a CI of 2.47 L$\cdot$min$\cdot$m$\sp2$. This difference was attributed to the significant difference in cardiac output (Q) based on the mathematical calculation of HR times SV. Both HR and SV in the two groups, however, did not differ significantly. These findings indicate that the intervention of UP did not alter significantly the hemodynamic parameters measured at 24 hours post CABG surgery. The results of this investigation suggest that either supine position or UP are comparable with regard to hemodynamic stability during the first six hours in the post CABG surgery patient.