The Science Journal of the American Association for Respiratory Care
Exhaled Nitric oxide (ENO) has been proposed as a noninvasive marker for lung disease. Currently there are two methods of measurement of ENO, (1) online direct-measurement as the patient exhales into the analyzer. (2) offline measurement of NO in exhaled gases collected in a reservoir bag. Offline measures are useful in that sampling can be performed at remote sites and stored for later measurement. We investigated the offline measurement from two Emergency Departments, one within our institution and the other a local Trauma center. Emergency room Personnel were trained in the procedure. We evaluated the data for reproducibility
Exhaled gases were collected into mylar balloons. The patient inhaled room air to total lung capacity then exhaled through a mouthpiece with 10 cm of PEEP as resistance to reduce nasal gas contribution to the sample, a known source of contamination. Two exhaled breaths were collected in mylar balloons with no breath hold, and two exhaled breaths were collected with a 15 second breath hold.
|GROUP||n||CORR||P VALUE||MEAN ±SE|
|BH #1||31||0.935||<0.001||25 ± 3|
|BH #2||25||0.935||<0.001||27 ± 4|
|NO BH#1||31||0.758||<0.001||24 ± 3|
|NO BH#2||24||0.758||<0.001||22 ± 2|
Table one is the statistical results of 31 patients sampled. There was no significant statistical difference between the two sets of samples with and without breath hold. ENO can be measured offline using a mylar balloon collection technique with accuracy and reproducibility. This method may find future value as a marker for pulmonary disease.