@article {Dellweg1323, author = {Dominic Dellweg and Markus Wenze and Ekkehard Hoehn and Olaf Bourgund and Peter Haidl}, title = {Humidification of Inspired Oxygen Is Increased With Pre-nasal Cannula, Compared to Intranasal Cannula}, volume = {58}, number = {8}, pages = {1323--1328}, year = {2013}, doi = {10.4187/respcare.02215}, publisher = {Respiratory Care}, abstract = {BACKGROUND: Oxygen therapy is usually combined with a humidification device, to prevent mucosal dryness. Depending on the cannula design, oxygen can be administered pre- or intra-nasally (administration of oxygen in front of the nasal ostia vs cannula system inside the nasal vestibulum). The impact of 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 analyzes 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 subjects 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 = 0.99, P \< .001). In our subjects intranasal humidity dropped significantly, from 40.3 {\textpm} 8.7\% to 35.3 {\textpm} 5.8\%, 32 {\textpm} 5.6\%, and 29.0 {\textpm} 6.8\% at flows of 1, 2, and 3 L, respectively, when oxygen was given intra-nasally without humidification (P = .001, P \< .001, and P \< .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, and independent of pre- or intranasal oxygen administration. CONCLUSIONS: Pre-nasal administration of dry oxygen achieves levels of intranasal humidity similar to those achieved by intranasal administration in combination with a bubble through humidifier. Pre-nasal oxygen simplifies application and may reduce therapy cost.}, issn = {0020-1324}, URL = {https://rc.rcjournal.com/content/58/8/1323}, eprint = {https://rc.rcjournal.com/content/58/8/1323.full.pdf}, journal = {Respiratory Care} }