The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

EFFECT OF BUBBLE CPAP AND HIGH FLOW NASAL CANNULA THERAPY ON THE ELECTRICAL ACTIVITY OF THE DIAPHRAGM IN A PREMATURE INFANT

Thomas C. Noblet; Respiratory Therapy, St.Vincent Women’s Hospital, Indianapolis, IN

Introduction: The effects of bubble CPAP and HFNC on the diaphragm’s electrical activity (Edi) are unknown. The Edi can be used to quantify neural respiratory drive to the diaphragm.1-2 Alterations of the Edi intensity with changes in therapy suggest changes in central respiratory drive.3 During therapeutic management of a premature infant, the Edi was monitored during bubble CPAP and during adjustments in flow using a HFNC (Vapotherm, Stevensville/MD). Case Summary: A 26-week old infant was intubated and received ventilatory support for respiratory distress using the SERVO-i. ventilator (Maquet, Inc., Solna, Sweden). A catheter for measuring the Edi (Maquet, Inc., Solna, Sweden) was nasally inserted to establish the infant’s current Edi level, and to begin ventilation with NAVA (neurally adjusted ventilatory assist). Shortly after catheter placement, the infant self-extubated in an unrelated event. The Edi catheter remained in place. The baby was placed on 5 cm H2O of bubble CPAP, which was increased to7 cm H2O to help improve oxygenation. Following initiation of bubble CPAP, the presence of sternal and intercostal retractions and the use of accessory muscles indicated labored breathing. The mean Peak Edi was 58.2 +/- 8.7 microvolts (normal range 5-10 microvolts). The elevated Edi suggested an increased neural input to the diaphragm. 2-3 The infant was switched to a high flow nasal cannula (HFNC, Vapotherm) to try to reduce the labored breathing. The flow through the HFNC was progressively increase from 2, 4, 6 to 8 L/min. Edi progressively decreased with each flow increase to an Edi minimum at a flow of 8 L/min (mean Edi Peak values [microvolts] 78 +/- 5.6; 60 +/- 7.2; 50.4 +/- 20.1; 24.3 +/- 4, respectively). Discussion: The high Edi level measured during bubble CPAP, and during lower flows with a HFNC suggest that the central respiratory drive to breath was high.1-3 Eight (8) L/min of HFNC produced the lowest Edi signal. The ability to monitor the effects of therapies such as bubble CPAP and HFNC on the diaphragm’s electrical activity may provide a tool in identifying how these therapies affect the Edi, which represents neural drive to the diaphragm.2 Sponsored Research - None

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