Reproducibility and accuracy of pulmonary artery pressure measurement in supine and lateral positions

The reproducibility and accuracy of pulmonary artery (PA) pressures in supine versus side-lying positions were compared in two groups of intensive care unit (ICU) patients. Side-lying measurements were reproducible, accurate, and clinically acceptable for surgical ICU patients, but not for medical ICU patients. The inconsistency was partly explained by the reference points used for transducer releveling in lateral positions. Surgical ICU used the fourth intercostal space and dependent midaxillary line; medical ICU used the fourth intercostal space and sternum. Reversing the leveling procedure in each ICU reduced surgical unit accuracy to an unacceptable level; medical unit accuracy was increased but was still too low for clinical acceptance. Further research is needed to identify appropriate anatomic reference points for transducer releveling in the side-lying position and to clarify which patient groups may be safely monitored by using this position.