1034 Nasal mask Average Volume-Assured Pressure Support versus Conventional Bilevel Respiratory Support in a 10-month-old infant with Congenital Central Hypoventilation Syndrome: A case report

Introduction Congenital central hypoventilation syndrome (CCHS) is a rare lifelong disorder characterised by alveolar hypoventilation and autonomic dysregulation secondary to mutations of the PHOX 2B genes. Treatment consists of assisted ventilation using positive pressure ventilators via tracheostomy, bi-level positive airway pressure (BPAP), negative pressure ventilators, or diaphragm pacing. Previous case studies have reported successful ventilation with early use of conventional nasal non-invasive BPAP in infants with CCHS without the need for tracheostomy. The case we describe is the first to report the use of average volume assured pressure support (AVAPS) feature through a nasal mask on an infant with CCHS. Report of case The 10-month-old female infant was born with a birth weight of 4590 grams to healthy parents after an uneventful pregnancy and delivery. Hypoxia, hypercarbia, respiratory distress and hypotonia were noted soon after delivery and the infant was resuscitated using intermittent positive airway pressure ventilation. She was subsequent put on non-invasive nasal BPAP for respiratory support in view of unexplained hypercarbia (PCO2 ranging 70 to 90 mmHg) on capillary blood gas. DNA analysis revealed that she carried a 25-repeat polyalanine expansion mutation of the PHOX 2B gene confirming CCHS. Her first sleep study on BPAP showed high variability in TcCO2 tracing. There was a rise in TcCO2 by more than 10 mmHg though it remained only slightly elevated above the normal range (35 to 47 mmHg).A second follow up sleep study was performed on the AVAPS feature, enabling the machine to automatically adjust the inspiratory pressures to deliver a constant targeted tidal volume. In our case, this feature led to a better transcutaneous carbon dioxide profile compared to conventional nasal non-invasive BPAP. Conclusion In summary, our case is unique as it is first to report the successful use of the AVAPS feature in an infant with CCHS. This case highlights that the AVAPS feature may be a reliable alternative to tracheostomy and conventional non-invasive BPAP in infants with CCHS. Randomised control trials are needed to compare the use of conventional BPAP and AVAPS feature in children and infants.