Electrical Activity of the Diaphragm (Edi) Metrics in Premature Infants Receiving Invasive Mechanical Ventilation Versus Noninvasive Respiratory Support.

backgroundIn neonatology, many of our patients require respiratory support for a variety of pathologies. However, there is little data regarding objective parameters to help guide this support. Decisions regarding the optimal level of support for each patient remain largely subjective. The electrical activity of the diaphragm (Edi) is a measure of neural respiratory drive and inspiratory load. This could serve as a useful tool to provide objective data regarding respiratory status, which in turn may aid in decision-making about optimal respiratory support.

objectivesThe primary objective of this study was to compare Edi metrics in infants who required invasive mechanical ventilation with those who remained on noninvasive modes of ventilation. The secondary objective was to compare the rates and severity of bronchopulmonary dysplasia (BPD) in the two groups. DESIGN/

methodsThis was a prospective observational pilot study. Infants admitted to the neonatal ICUs (NICUs) at Hassenfeld Children's Hospital and Bellevue Hospital Center, born at a gestational age of 26-32 weeks and weighing >500 grams, were eligible for the study. An Edi catheter (Maquet Critical Care AB, Solna, Sweden) was placed within the first 24 hours of life and remained in place for 72 hours. Subjects were weaned or escalated on their respiratory support based on current unit practice guidelines. They were separated into two groups: those who required invasive mechanical ventilation and those who did not. Paired Student's t-tests, chi-square tests, and Mann-Whitney tests were used to evaluate statistical significance (p ≤ 0.05).

resultsA total of 29 subjects were enrolled: 15 in the intubated group and 14 in the noninvasive group. Edi minimum was significantly lower, and delta Edi (the difference between Edi peak and minimum) was higher in the non-intubated group. There were no statistical differences in Edi peaks between the groups, although there was a trend toward higher peaks in the noninvasive group. Additionally, BPD outcomes were not statistically different.

conclusionsThe lower Edi minimum in the non-intubated group suggests less severe lung disease and milder respiratory distress syndrome (RDS), requiring less stimulus and external support to generate adequate distending pressure to maintain alveolar patency at end-expiration. The higher delta Edi indicates a greater intrinsic ability to generate an adequate tidal volume for ventilation. There is wide variation in practice regarding modes of ventilation, both invasive and noninvasive, with no clear best practice. We lack objective data to guide our practice. This study is the first to examine Edi metrics as a monitoring tool to assess the degree of disease severity and sufficiency of support provided. Our results suggest that using Edi metrics may provide more data to help standardize and guide clinical practice.