Mechanisms of airway protection after pharyngeal fluid infusion in healthy,
sleeping piglets.
Page, Megan, Heather E. Jeffery, Virginia Marks, Elizabeth J. Post & Andrew K.
W. Wood.
Departments of Obstetrics and Gynaecology, Veterinary Physiology and
Clinical Studies, The University of Sydney, Sydney, 2006, Australia
APStracts 2:0013A, 1995.
The airway protective mechanisms evoked following infusion of fluids into the
pharynx was examined in the intact and healthy, newborn piglet, during sleep.
Thirteen healthy, normothermic piglets (3-6 days of age) were examined on 4
consecutive days, during sleep. The fluids infused (0.05-1.5ml) were 0.9%
saline, distilled water and hydrochloric acid (HCl; pH3 and pH2). Respiratory
rate, heart rate, oxygen saturation (SaO2), swallowing, and arousal were
compared pre and post infusion during active (AS) and quiet sleep (QS), for
each test fluid. The most common response in AS and QS was swallowing (90%),
then arousal (24%), however, no apnea occurred, and respiratory rate and SaO2
were always maintained. A significant difference occurred between HCl
infusions of pH2 and pH3; at pH2 the frequency of swallows and latency to the
first swallow were reduced (p<0.05), and the frequency of arousal was reduced
in AS compared to QS (p<0.01). Airway protection following pharyngeal fluid
stimulation is achieved, primarily by swallowing and arousal, without any
effect on respiratory rate and SaO2. Attenuation of protection mechanisms
occurred, however, when the infusate was at pH2.
Received 29 July 1994; accepted in final form 16 January 1995.
APS Manuscript Number A778-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 February 1995.