Postural variations in pulmonary resistance, dynamic compliance, and esophageal pressure in neonates

Abstract

In order to determine effect of posture and to assess the reliability of the esophageal balloon method for measuring esophageal pressure changes (delta Pes) under clinical conditions, lung mechanics were measured in 13 term and preterm babies in each of 3 postures: supine, right, and left lateral. The pulmonary resistance (Rp) was significantly lower and the dynamic compliance (Cdyn) higher in the right lateral than in the supine position. Judged by the occlusion test, delta Pes was recorded accurately in each posture. The mean end-expiratory esophageal balloon pressure (PesEE) was higher in preterm infants and in the supine posture. It is concluded that the (right) lateral posture is mechanically less demanding than the supine posture and that delta Pes can be measured accurately in the supine posture. Absolute values of PesEE have no physiologic meaning and should not be used for patient management or for the calculation of lung mechanics.