Exhaled and nasal nitric oxide in laryngectomized patients

Background: Nitric oxide (NO) shows differing concentrations in
lower and upper airways. Patients after total laryngectomy are the
only individuals, in whom a complete separation of upper and lower
airways is guaranteed. Thus the objective of our study was to
assess exhaled and nasal NO in these patients. Methods: Exhaled
bronchial NO (FENO) and nasal nitric oxide (nNO) were measured in
patients after total laryngectomy (n = 14) and healthy controls (n
= 24). To assess lung function we additionally performed
spirometry. Co-factors possibly influencing NO, such as smoking,
infections, and atopy were excluded. Results: There was a markedly
(p < 0.001) lower FENO in patients after total laryngectomy
(median (range): 4 (1-22) ppb) compared to healthy controls 21
(9-41) ppb). In contrast, nNO was comparable between groups (1368
versus 1380 in controls) but showed higher variability in subjects
after laryngectomy. Conclusions: Our data suggest that either
bronchial NO production in patients who underwent laryngectomy is
very low, possibly due to alterations of the mucosa or oxidant
production/inflammation, or that substantial contributions to FENO
arise from the larynx, pharynx and mouth, raising FENO despite
velum closure. The data fit to those indicating a substantial
contribution to FENO by the mouth in healthy subjects. The broader
range of nNO values found in subjects after laryngectomy may
indicate chronic alteration or oligo-symptomatic inflammation of
nasal mucosa, as frequently found after total laryngectomy.