Am. J. Respir. Crit. Care Med., Vol 151, No. 2, Feb 1995, 455-460.
Hypoglossal nerve stimulation affects the pressure-volume behavior of the upper airway
W Hida, H Kurosawa, S Okabe, Y Kikuchi, J Midorikawa, Y Chung, T Takishima and K Shirato
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
To determine the effects of electrical hypoglossal nerve and submental
stimulation on upper airway collapsibility, we examined the pressure-
volume (P-V) relationships during bilateral supramaximal stimulation of the
distal cut hypoglossal nerve ends over a range of frequencies from zero to
100 Hz in the sealed upper airway of 10 anesthetized supine dogs. Animals
were artificially ventilated with 50% O2 and maintained under relative
hyperoxia and hypocapnia during the study to eliminate the ventilatory
drive output. Sealed upper airway pressures were obtained during random
injections of different volumes of air from zero to 50 ml with and without
hypoglossal nerve stimulation, and the upper airway P-V curves were
obtained. The characteristics of the P-V curves were as follows: (1) the
upper airway compliance defined as the slope of the regression of P-V
curves fell from 4.07 +/- 0.33 ml/cm H2O without stimulation to 3.02 +/-
0.30 ml/cm H2O with stimulation at 50 Hz and plateaued at frequencies
greater than 50 Hz, and (2) the volume at a given pressure during
stimulation was larger than that without stimulation. The effects of
submental stimulation on upper airway collapsibility were similar to those
of hypoglossal nerve stimulation. These results suggest that the increase
of upper airway muscle tone by hypoglossal nerve or submental stimulation
stiffens the upper airway and that increases in muscle tone expand the
upper airway.
