Effects of Lung Squeezing Technique on Lung Mechanics in Mechanically-Ventilated Preterm Infants with Respiratory Distress Syndrome

Effects of conventional chest physiotherapy on preterm infants may be compromised due to the maturation difference in immature lungs. The lung squeezing technique (LST) has been shown to be beneficial in correcting atelectasis in preterm infants. The purpose of this study was to investigate the effects of LST on the parameters of lung mechanics in preterm infants on mechanical ventilation. LST was used as an intervention to improve the distribution of ventilation in infants with respiratory distress syndrome. Eleven preterm infants on mechanical ventilation were enrolled. Serial measurements on static respiratory system compliance (Crs) and resistance (Rrs) by an airway occlusion technique with passive flow-volume analysis were performed before and immediately after LST, and repeated 4 hours later to assess the carryover effect. Crs improved by 21% (0.92 ± 0.37 mL/cmH2O/kg vs. baseline 0.76 ± 0.33 mL/cmH2O/kg, p = 0.023) immediately after LST. Split group analysis showed that only the lower Crs group had a significant carryover effect at 4 hours post-LST (p = 0.046). LST increases total respiratory system compliance, possibly through decompression of the overdistended lung units and recruitment of atelectatic alveoli. Rrs showed no significant change after LST. Individual trends of decreased Rrs were observed in infants with obvious secretion. The effect of LST on respiratory system resistance needs to be further explored by recruiting other disease conditions that present with pulmonary secretions.