Abstract
Introduction: Nasal high flow (NHF) is increasingly used as a form of respiratory support in neonates, although the physiological mechanisms of this therapy remain unclear.
Aim: The aim of the study was to investigate ventilatory changes during NHF therapy in healthy newborns.
Methods: Calibrated respiratory inductance plethysmography (RIP) was conducted on 17 (10M/7F) neonates with a mean gestation age 39.4 (SD 1.2) weeks and mean birth weight of 3200 (SD 371.6) g. NHF at 8 L/min via a nasal cannula (AIRVO2™, Optiflow™, Fisher & Paykel Healthcare, NZ) and control were applied in a randomized order during sleep. Sleep was recorded by electroencephalography and video. Gas exchange was assessed by oxygen saturation (SpO2) and transcutaneous carbon dioxide (TcCO2). Data were analyzed using paired t-test.
Results: A variable ventilatory response was observed during NHF without change in TcCO2 (36.39 vs. 36.66 mmHg, p=0.79) or SpO2 (98.13 vs. 98.63%, p=0.41). There was no significant change in tidal volume (0.0113 vs. 0.0124 L, p=0.21) or respiratory rate (46.6 vs. 50.2 min-1, p=0.48) however, NHF produced a significant reduction in minute ventilation (MV), 0.664 (SD 0.207) to 0.506 (SD 0.145) L/min (p=0.0006)
Conclusion: NHF (8L/min) produced a variable ventilatory response in neonates with a significant reduction in MV (24%) without evidence of change in blood gases. The findings may be explained by reduction of dead space ventilation during NHF.
- Copyright ©the authors 2016
