Impact of Body Position on Lung Deposition of Nebulized Surfactant in Newborn Piglets on Nasal Continuous Positive Airway Pressure.

ABSTRACT

INTRODUCTION: The ideal body position during surfactant nebulization is not known. OBJECTIVE: The aim of this study was to determine whether body positioning during surfactant nebulization influences surfactant distribution and deposition in the lungs. METHODS: Twenty-four 12- to 36-h-old full-termpiglets (1.3-2.2 kg) on nasal continuous positive airway pressure (nCPAP) were randomized into four groups lateral decubitus with right or left side up, prone or supine positions (n = 6 each). All animals received 200 mg kg-1 of poractant alfa mixed with 200 MBq of 99mtechnetium-nanocolloid via a customized eFlow-Neos investigational vibrating-membrane nebulizer. Surfactant deposition (percentage of the administered dose) was measured by gamma scintigraphy. RESULTS: Comparing all groups, the mean total lung surfactant deposition was significantly higher in the prone position (32.4 ± 7.7%, p = 0.03). The deposition in this group was higher in the right lung (21.0 ± 8.6 vs. 11.3 ± 5.7%, p = 0.04). When nebulization was performed in the lateral decubitus, most of the surfactant was found in the dependent lung, regardless of which side the piglet lay on (right side up 15.3 ± 1.0 vs. 3.4 ± 1.0%, p = 0.06, and left side up 11.2 ± 9.8 vs. 1.8 ± 0.7%, p = 0.04). CONCLUSIONS: In spontaneously breathing animals on nCPAP, the prone position yielded the highest lung dose. Higher deposition rates in the dependent lung while on lateral decubitus indicates that deposition was also influenced by gravity.