The Effect of Lateral Body Positions Upon Pulmonary Artery and Pulmonary Wedge Pressures in Critically Ill Patients

The effect of lateral body positions on pulmonary artery pressures and pulmonary capillary wedge pressure was studied in a clinical comparative study using eight critically ill patients. Pulmonary artery pressures (systolic, diastolic, and mean) and pulmonary capillary wedge pressure measurements were taken with the patients in three different positions, i.e., supine flat, right lateral, left lateral. Comparison was made between the control data (pressure measurements in the supine flat position) and the pressure measurements in each lateral body position. Mean pressures were lower in the lateral body positions than those in the supine flat position, ranging from 0.1 mm Hg to 3.3 mm Hg lower. F-ratios for all pressure differences in relation to position were not significant at the 0.05 level. It was concluded that for the eight critically ill patients in the study, taking the pulmonary artery pressures and pulmonary capillary wedge pressure measurements in the lateral body positions, utilizing the external reference points as described, resulted in insignificant differences in pressure measurements. No generalization of the findings can be made to other critically ill patients