Evolution of inspiratory diaphragm activity in children over the course of the PICU stay

Purpose Diaphragm function should be monitored in critically ill patients, as full ventilatory support rapidly induces diaphragm atrophy. Monitoring the electrical activity of the diaphragm (EAdi) may help assess the level of diaphragm activity, but such monitoring results are difficult to interpret because reference values are lacking. The aim of this study was to describe EAdi values in critically ill children during a stay in the pediatric intensive care unit (PICU), from the acute to recovery phases, and to assess the impact of ventilatory support on EAdi. Methods This was a prospective longitudinal observational study of children requiring mechanical ventilation for ≥24 h. EAdi was recorded using a validated method in the acute phase, before extubation, after extubation, and before PICU discharge. Results Fifty-five critically ill children were enrolled in the study. Median maximum inspiratory EAdi (EAdi max ) during mechanical ventilation was 3.6 [interquartile range (IQR) 1.2–7.6] μV in the acute phase and 4.8 (IQR 2.0–10.7) μV in the pre-extubation phase. Periods of diaphragm inactivity (with no detectable inspiratory EAdi) were frequent during conventional ventilation, even with a low level of support. EAdi max in spontaneous ventilation was 15.4 (IQR 7.4–20.7) μV shortly after extubation and 12.6 (IQR 8.1–21.3) μV before PICU discharge. The difference in EAdi max between mechanical ventilation and post-extubation periods was significant ( p