PC3006: Diaphragm Pacing in an Infant with Respiratory Failure Secondary to Unilateral Diaphragm Paresis: A Promising Intervention

Introduction: Diaphragm dysfunction can result in respiratory failure and ventilator dependence. Diaphragm pacing is an established intervention for disease processes affecting diaphragm function such as spinal cord injuries, congenital central alveolar hypoventilation syndrome, unilateral dysfunction, and neuromuscular disorders. Although studies have shown pacing can decrease ventilator dependence, there is a lack of literature within the pediatric population. This case explores the clinical course of the youngest reported patient implanted with the new temporary diaphragm pacing system FDA authorized for emergency use during the COVID-19 pandemic.

Case Description: A 37 week female was transferred to our NICU for respiratory distress after birth. Physical exam was significant for severe retrognathia, redundant neck skin folds, posteriorly rotated ears, wide spaced nipples, holosystolic murmur, and a large anterior fontanelle. Further evaluation showed horseshoe kidney, uterine didelphys, patent ductus arteriosus, and left vocal cord paresis. During the first two weeks of life, her respiratory status worsened requiring intubation and mechanical ventilation. Several failed extubation attempts despite mandibular distraction, and an intermittently elevated right hemidiaphragm (Figure 1) with no hernia or eventration seen on CT prompted a diaphragm ultrasound that showed asymmetrical movement concerning for right hemidiaphragm paresis. At 10 weeks old, patient underwent tracheostomy and implantation of diaphragm pacing electrodes. Diaphragm conditioning began the day after implantation with gradually increasing settings. Her diaphragm EMG activity steadily improved (Figure 2) and ventilator settings were weaned to CPAP pressure support. After six weeks of pacing and consistent progression in EMG activity, the pacer was turned off and repeat ultrasound showed increased spontaneous right hemidiaphragm movement. At four months old, patient was discharged home without pacing. On outpatient follow-up, she continued to do well on the same respiratory support without evidence of apneas and electrodes were removed. Of note, genetic testing showed a PBX1 variant, associated with the rare disorder Congenital Anomalies of Kidney and Urinary Tract Syndrome with or without Hearing Loss, Abnormal Ears, or Developmental Delay (CAKUTHED). A relationship between diaphragm paresis and CAKUTHED is not known.

Discussion: Diaphragm pacing benefited our patient by strengthening the diaphragm muscle, improving spontaneous respiratory effort, and allowing weaning of ventilator support. Our patient was discharged without pacing or a mandatory ventilation rate; supporting the concept that short-term pacing in the pediatric population can have a positive effect on diaphragm function. Given our patient’s experience, we encourage providers to evaluate for diaphragm dysfunction in neonates with extubation failures of unclear etiologies as pacing is now a feasible option in infants. Large prospective studies are needed to evaluate optimal timing and management of diaphragm pacing in pediatric patients.

Conclusion: Diaphragm pacing should be considered as an intervention for infants with diaphragm dysfunction and is available through the temporary diaphragm pacing system FDA authorized for emergency use.