Objective: The electrical activity of the diaphragm (Edi) reflects neural respiratory drive. Edi peak correlates with inspiratory drive and Edi minimum (Edi min) correlates with the tonic activity of the diaphragm. Edi data in non-ventilated preterm neonates have not been determined.The primary aim of this study was to determine Edi values in non-ventilated preterm neonates throughout postnatal maturation and with various types of noninvasive respiratory support. The secondary aim was to evaluate the success or complications of placement of the Edi catheter in premature neonates.
Study design: This was a prospective observational study of non-ventilated neonates <33 weeks gestation. Data were collected weekly using an Edi catheter placed in neonates on highflow nasal cannula (HFNC), nasal cannula (NC) or room air (RA). Clinical stability was determined by measuring heart rate (HR), respiratory rate (RR) and oxygen saturation (Sats). Success and adverse events of Edi catheter placement was monitored. Statistics were obtained by analysis of variance, P<0.05 was considered significant.
Result: Seventeen neonates were enrolled at 26 to 33 weeks postmenstrual age and studied from 1 to 10 weeks in duration. Overall Edi peak was 10.8±3.7 mcV (range 3.7 to 18.7) and Edi min was 2.8±1.1 mcV (range 0.8 to 7.6). There was no difference in Edi peak and min over postmenstrual ages within or between neonates, and no difference between those neonates on HFNC, NC or RA. HR, RR and Sats were not different over postmenstrual age or between any groups. The Edi catheter was placed successfully in 100% of these neonates. There were no adverse events noted.
Conclusion: In clinically stable neonates, the inspiratory drive (Edi peak) and tonic activity (Edi min) do not change with postnatal maturation or with the level of noninvasive respiratory support. The Edi catheter can be placed successfully in these premature neonates. These Edi data have the potential to guide ventilatory management of premature neonates.