Surfactant application during extracorporeal membrane oxygenation improves lung volume and pulmonary mechanics in children with respiratory failure

Abstract

Introduction: This study was performed to determine whether surfactant application during extracorporeal membrane oxygenation (ECMO) improves lung volume, pulmonary mechanics, and chest radiographic findings in children with respiratory failure or after cardiac surgery.

Methods: This was a retrospective chart review study in a pediatric intensive care unit (PICU). Seven patients received surfactant before weaning from ECMO was started (group S). They were compared to six patients treated with ECMO who did not receive surfactant (group C). These control patients were matched based on age, weight, and underlying diagnosis. Demographic data, ventilator settings, tidal volume, compliance of respiratory system (calculated from tidal volume/(peak inspiratory pressure - positive end-expiratory pressure), and ECMO flow were extracted. Chest radiographs were scored by two blinded and independent radiologists. Changes over time were compared between groups by repeated-measures analysis of variance (time*group interaction). Values are given as percentages of baseline values.

Results: The groups did not differ with regard to demographic data, duration of ECMO, ventilator settings, PICU and hospital days. After application of surfactant, mean tidal volume almost doubled in group S (from 100% before to 186.2%; p = 0.0053). No change was found in group C (100% versus 98.7%). Mean compliance increased significantly (p = 0.0067) in group S (from 100% to 176.1%) compared to group C (100% versus 97.6%). Radiographic scores tended to decrease in group S within 48 h following surfactant application. ECMO flow tended to decrease in group S within 10 h following surfactant application but not in group C. Mortality was not affected by treatment.

Conclusion: Surfactant application may be of benefit in children with respiratory failure treated with ECMO, but these findings need confirmation from prospective studies.

Figure 1

Tidal volumes (VT) of the surfactant group (group S) and control group (group C). The X-axis represents the time points before (baseline) and 4 and 10 h after surfactant application for group S. For group C, the time points are baseline (mid-time of the ECMO course) and 4 and 10 h thereafter. The Y-axis represents values of VT as percentages of baseline values. VT showed a significant increase over time in group S compared to group C (repeated-measures, analysis of variance, group*time interaction, p = 0.0053).

Figure 2

Compliance of respiratory system (Crs) calculated from the ratio tidal volume/(peak inspiratory pressure – positive end-expiratory pressure) for the surfactant group (group S) and control group (group C). The X-axis represents the time points before (baseline) and 4 and 10 h after surfactant application for group S. For group C, the time points are baseline (mid-time of the ECMO course) and 4 and 10 h thereafter. The Y-axis represents values of Crs as percentages of baseline values. Crs showed a significant increase over time in group S compared to group C (repeated-measures, analysis of variance, group*time interaction, p = 0.0067)

Figure 3

Respiratory distress syndrome severity score (RDS) for the surfactant group (group S) and control group (group C). The X-axis represents time points when radiographs were obtained and scored (baseline (before surfactant application) and 24 and 48 h thereafter) for group S, and for group C at baseline (mid-time of ECMO-course) and 24 and 48 h thereafter. The Y-axis represents the radiographic RDS score.

Figure 4

ECMO flow for the surfactant group (group S) and control group (group C). The X-axis represents the time points before (baseline) and 4 and 10 h after surfactant application for group S. For group C, the time points are baseline (mid-time of the ECMO course) and 4 and 10 h thereafter. The Y-axis represents ECMO flow as percentages of baseline values.