RT Journal Article
SR Electronic
T1 Humidification of inspired oxygen is increased with a pre-nasal cannula compared to intranasal cannula
JF Respiratory Care
FD American Association for Respiratory Care
SP respcare.02215
DO 10.4187/respcare.02215
A1 Dominic Dellweg
A1 Markus Wenze
A1 Ekkehard Hoehn
A1 Olaf Bourgund
A1 Peter Haidl
YR 2013
UL http://rc.rcjournal.com/content/early/2013/01/02/respcare.02215.abstract
AB Background: Oxygen therapy is usually combined with a humidification device to prevent mucosal dryness. Depending of the cannula design oxygen can be administered pre- or intra-nasally (administration of oxygen in front of the nasal ostia versus cannula system inside the nasal vestibulum). The impact of the cannula design on intra-nasal humidity however has not been investigated to date. Objective: First, to develop a system, that samples air from the nasal cavity and analyses the humidity of these samples. Second, to investigate nasal humidity during pre-nasal and intra-nasal oxygen application with and without humidification. Methods: We first developed and validated a sampling and analysis system to measure humidity from air samples. By means of this system we measured inspiratory air samples from 12 individuals who received nasal oxygen with an intra-nasal and pre-nasal cannula at different flows with and without humidification. Results: The sampling and analysis system showed good correlation to a standard hygrometer within the tested humidity range (r = 0.992, p < 0.001). In our subjects intranasal humidity dropped significantly from 40.3 ± 8.7 % to 35.3 ± 5.8 %, 32 ± 5.6 % and 29.0 ± 6.8 % at a flow of one, two and three litres respectively when oxygen was given intra-nasally without humidification (p=0.001, p<0.001 and p<0.001 respectively). We observed no significant change in airway humidity when oxygen was given pre-nasally without humidification. With the addition of humidification we observed no significant change in humidity at any flow rate and independent of pre- or intranasal oxygen administration. Conclusion: Pre-nasal administration of dry oxygen achieves similar levels of intranasal humidity as intranasal administration in combination with a bubble through humidifier. Pre-nasal oxygen simplifies application and may reduce therapy cost