Determinants of fatal apnea responses to acid stimulation of the larynx in piglets.
OBJECTIVE
This study explores the physiological determinants of laryngeal chemoreflex (LCR) response severity under hypoxic conditions.


METHODS
Thirty-four piglets underwent hypoxic laryngeal stimulation. Physiologic data were collected, and responses were graded as mild, moderate, or profound.


RESULTS
Prestimulation hypoxia caused respiratory depression and carbon dioxide retention in profound responders and respiratory stimulation in mild and moderate responders (p < .05). Resumption of respiration occurred in all animals when the PaCO2 rose by a mean +/- SD of 15.1 +/- 6.5 mm Hg (p > .05). There was a significant difference between mild, moderate, and severe responders in change in arterial PaO2 and hydrogenated hemoglobin saturation during the LCR-induced response (p < .001 for both).


CONCLUSIONS
Resumption of respiration is associated with accumulation of arterial PaCO2. The respiratory response to hypoxia predicts the severity of the LCR response. The severity of the LCR-induced response is associated with changes in arterial PaO2 and hydrogenated hemoglobin saturation during the LCR-induced apnea.
Heman-Ackah
Yolanda D
YD
Department of Otolaryngology-Head and Neck Surgery, University of Illinois at Chicago, Chicago, Illinois, USA.
D000818:Animals; D001049:Apnea / Q000503:physiopathology*; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D000860:Hypoxia / Q000503:physiopathology*; D007830:Larynx / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D013552:Swine
D002245:Carbon Dioxide; D010100:Oxygen