Impact of Spontaneous Breathing Trial on Work of Breathing Indices Derived From Esophageal Pressure, Electrical Activity of the Diaphragm, and Oxygen Consumption in Children

Abstract

BACKGROUND: The present study aimed to characterize the behavior of 3 components of respiratory muscle function during mechanical ventilation weaning in children to better understand the respective impact of a spontaneous breathing trial on ventilatory mechanical action (esophageal pressure [P_es], ventilatory demand (electrical activity of the diaphragm [EA_di]), and oxygen consumption. METHODS: This was a prospective single-center study. All children ≥ 1 months and es, and EA_di were performed during 3 steps: before, during, and after the spontaneous breathing test. RESULTS: Twenty subjects (median age, 5.5 mo) were included. Half of them were admitted for a respiratory cause. The increase in P_es swings and esophageal pressure-time product during the spontaneous breathing trial was not significant (P = .33 and P = .75, respectively), and a similar trend was observed with peak EA_di (P = .06). Oxygen consumption obtained by indirect calorimetry was stable in the 3 conditions (P = .98). CONCLUSIONS: In these children who were critically ill, a spontaneous breathing trial induced a moderate and nonsignificant increase in work of breathing, as reflected by the respiratory drive with EA_di and respiratory mechanics with P_es. However, indirect calorimetry did not seem to be a sensitive tool to assess respiratory muscle function during the weaning phase in children who were on mechanical ventilation, especially when work of breathing was slightly increased.