Abstract
Nasal high flow oxygen therapy (NHF) and continuous positive airway pressure (CPAP) are modes of non-invasive respiratory support used to improve respiratory function in multiple patient groups. Both therapies provide positive pressure although this varies during the respiratory cycle. The purpose of this study was to measure and compare the airway pressure generated during different phases of the respiratory cycle in patients receiving NHF at various gas flows.
Methods Patients scheduled for elective cardiac surgery were approached and invited to participate in this study. Nasopharyngeal pressure measurements were performed using nasal high flow with gas flow rates of 30, 40 and 50 L/min. All measurements were performed in random order with patients breathing mouth closed.
Results Mean (SD) nasopharyngeal airway pressures of 1.4 (0.6), 2.2 (0.8) and 3.0 (1.0) were recorded at 30, 40 and 50 L/min using nasal high flow. Analyses also determined the mean peak expiratory and mean expiratory plateau pressures.
Conclusion This study describes the airway pressures generated by NHF. Expiratory pressures during NHF were higher than the mean pressures previously reported for this therapy. We believe this may account in part for the disproportional clinical effects seen with NHF.
Footnotes
- Cardiothoracic and Vascular Intensive Care Unit, Auckland City Hospital, Private Bag 92024, Auckland 1010, New Zealand, Email: rparke{at}adhb.govt.nz, Phone 006421893176, Fax: 006493074906
- Copyright © 2013 by Daedalus Enterprises Inc.
