Journal of Applied Physiology, Vol 79, Issue 5 1567-1570, Copyright © 1995 by American Physiological Society
Superior laryngeal nerve blockade and inspiratory resistive load detection in normal subjects
M. F. Fitzpatrick, T. Zintel, M. Stockwell, J. Mink and C. G. Gallagher
Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Canada.
The site for detection of added inspiratory resistive loads is unknown, but
recent evidence suggests that the airways may play an important role. The
aim of this study was to discern whether the larynx has an important
independent role in conscious detection of added inspiratory resistive
loads. A randomized double-blind placebo-controlled study of the effect of
superior laryngeal nerve blockade on inspiratory resistive load-detection
threshold was carried out in 12 normal subjects (7 women; mean age 27.5 yr;
range 18-45 yr). Baseline (preinjection) detection thresholds were similar
on the lidocaine [0.58 +/- 0.16 (SE) cmH2O.l-1.s] and saline (0.53 +/- 0.12
cmH2O.l-1.s; P = 0.28) days. There was no significant difference in
load-detection thresholds after injection between lidocaine (0.60 +/- 0.15
cmH2O.l-1.s) and saline (0.55 +/- 0.10 cmH2O.l-1.s; P = 0.68). Thus, the
larynx does not appear to be an important independent airway site for
conscious inspiratory resistive load detection.
