PT - JOURNAL ARTICLE AU - Rogers, Kirstie AU - Fettes, Emma AU - Samuels, Martin TI - 69 Hypoxic challenge testing in children using phrenic nerve pacing AID - 10.1136/bmjpo-2023-GOSH.20 DP - 2023 Dec 01 TA - BMJ Paediatrics Open PG - A10--A11 VI - 7 IP - Suppl 2 4099 - http://bmjpaedsopen.bmj.com/content/7/Suppl_2/A10.3.short 4100 - http://bmjpaedsopen.bmj.com/content/7/Suppl_2/A10.3.full SO - BMJ Paediatrics Open2023 Dec 01; 7 AB - Background Phrenic nerve pacing (PNP) uses implanted devices to provide diaphragmatic stimulation from repeated electrical stimulation of the phrenic nerves in children with central hypoventilation disorders. Hypoxic Challenge Testing (HCT) is performed in respiratory disorders to assess whether patients need oxygen supplementation (O2) during flying. As children with hypoventilation disorders may worsen if given O2 alone, we aimed to assess whether children with PNP need O2 or respiratory support when flying.Method An adapted HCT protocol monitored oxygen saturation (SpO2) and transcutaneous pCO2 (tcpCO2) in a hypoxic environment (15% O2) used to simulate the aircraft cabin at altitude.1 Children with PNP were monitored self-ventilating (SV) in air, and then with PNP in a hypoxic chamber to see if it provides adequate ventilation to maintain SpO2 >90%, the threshold for O2.Results We performed HCT in two patients (1 male) with PNP. They had normal baseline SpO2(98-99%) in room air and desaturated to <90% when self-ventilating in the hypoxic chamber. Phrenic nerve pacing increased SpO2 to baseline (96-97%) in both patients and O2 was not required. TcpCO2 rose from baseline when SV in 15% FiO2, but returned to baseline once PNP started.Conclusion PNP maintained SpO2 at baseline, without the need for O2 in children with central hypoventilation disorders. This confirmed that PNP alone during a flight can appropriately support a patient to maintain SpO2 above 90%. PNP avoids hypoventilation during flight that is masked by oxygen use, and in addition improves convenience for families when flying, as in-flight oxygen is not needed.Reference Riley M, Brotherston S, Kelly P, Samuels M, Pike KC. Modified hypoxic challenge testing in children needing nocturnal ventilation: an observational study. Pediatr Pulmonol. 2022;1‣10. doi:10.1002/ppul.26163