Neonatal chest wall suspension splint: A novel and noninvasive method for support of lung volume

Abstract

Surfactant and musculoskeletal immaturity results in lower compliance of the lung relative to the chest wall, with clinical manifestations of low lung volume, marked chest wall retractions (CWR), and thoracoabdominal asynchrony. Inspiratory efforts are dissipated on distorting the chest wall inward rather than recruiting lung volumes. The current study tests the hypothesis that a novel neonatal chest wall suspension splint (SP), designed to provide stability to the compliant chest wall, would reduce inspiratory chest wall retractions and improve lung volumes. Nine preterm infants (29 +/- 1 SE weeks of gestation; 1.59 +/- 0.27 SE kg study weight) were studied at 16 +/- 5 SE days of life at baseline (BL) and following application of the front plate (FP) and the full SP (Hug n Snug Neonatal Chest Splint, Respironics, Inc.). Phase angle of thoracoabdominal motion, CWR, functional residual capacity (FRC), and pulmonary function were evaluated during spontaneous breathing. Compared to BL, there was a significant decrease in anterior CWR (2.21 +/- 0.91 SE vs. 0.25 +/- 0.09 SE mm; P < 0.05), an increase in FRC (16.6 +/- 2.8 SE vs. 27.8 +/- 5.5 SE ml/kg; P < 0.05) and tidal volume (4.8 +/- 1.5 SE vs. 7.3 +/- 1.4 SE ml/kg; P < 0.05), minimal effect on pulmonary compliance (1.98 +/- 0.50 SE vs. 1.72 +/- 0.30 SE ml/cmH2O/kg), and a trend for a decrease in phase angle (128.4 +/- 10.9 SE vs. 111.8 +/- 19.3 SE) with the application of the splint. FRC correlated inversely with severity of CWR across all conditions (P < 0.05, r = -0.68). Phase angle was directly correlated to anterior CWR (r = 0.72; P < 0.05) and correlated inversely with FRC (P < 0.005; r = -0.56). We speculate that by improving CW stability, the use of this splint may reduce the energetic requirements of breathing and, potentially, the need for more invasive ventilatory support in the neonate.