Document Detail

The laryngeal chemoreflex: an evaluation of the normoxic response.
MedLine Citation:
PMID:  19172628     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: The laryngeal chemoreflex is a reflexive central apnea, bradycardia, and cardiovascular collapse that occurs in young, maturing mammals in response to exposure of the laryngeal mucosa to acidic and/or organic stimuli. The severity of the laryngeal chemoreflex varies within a species from one animal to another, and in some animals, the response can be fatal. This study seeks to identify those factors that contribute to fatal laryngeal chemoreflex responses when the larynx is stimulated under normoxic conditions, and to define how the normoxic response differs from the hypoxic laryngeal chemoreflex response. STUDY DESIGN: This is a prospective study evaluating the response to laryngeal stimulation of 80 newborn piglets. METHODS: The laryngeal chemoreflex response was elicited from 67 piglets under normoxic conditions. The data were collected from a combination of three separate experimental protocols, each of which included inducing the laryngeal chemoreflex under normoxic conditions as the first step. The physiologic response was recorded with a combination of arterial blood gas, pulse oximetry, blood pressure, and continuous cardiac monitoring. RESULTS: Resumption of respirations occurred when the pCO(2) rose by a mean of 8.34 (Standard Deviation [SD] = 4.8) mmHg, regardless of response severity (ANOVA, P > .05). Moderate (requiring supplemental O(2) for recovery) and profound (fatal) responders had a significantly higher prestimulation pCO(2) (95% confidence interval [CI] 39.8-44.8 mmHg and 40.5-46.4 mmHg, respectively) than did mild (recovery without assistance) responders (95% CI 36.8-40.8 mmHg, ANOVA, P < .05). Baseline pH was statistically significantly different as a function of response severity (95% CI profound: 7.29-7.37, moderate: 7.33-7.38, and mild 7.36-7.39, P < .05). CONCLUSIONS: Accumulation of arterial CO(2) is associated with resumption of respirations during the normoxic laryngeal chemoreflex. The combination of an elevated prestimulation pCO(2) and a low prestimulation pH predicts a profound laryngeal chemoreflex response under normoxic conditions.
Yolanda D Heman-Ackah; Kerri J Pernell; George S Goding
Related Documents :
7834998 - Plasma endogenous digoxin-like substance levels are dependent on blood o2 in man.
23142808 - Obesity-related alterations in cardiac lipid profile and nondipping blood pressure patt...
6652258 - Action of almitrine on the pulmonary vasculature in ferrets and rats.
10635008 - Recent advances in human physiology at extreme altitude.
18632588 - Stepwise increase in the prevalence of isolated systolic hypertension with the stages o...
20627878 - Precision and accuracy of a new device (cnaptm) for continuous non-invasive arterial pr...
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Laryngoscope     Volume:  119     ISSN:  1531-4995     ISO Abbreviation:  Laryngoscope     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-02-02     Completed Date:  2009-03-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8607378     Medline TA:  Laryngoscope     Country:  United States    
Other Details:
Languages:  eng     Pagination:  370-9     Citation Subset:  IM    
Department of Otolaryngology, Head and Neck Surgery, Drexel University College of Medicine, Philadelphia, PA 19103, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Analysis of Variance
Animals, Newborn
Blood Gas Analysis
Blood Pressure Determination
Electric Stimulation
Laryngeal Mucosa / physiopathology
Laryngeal Muscles / physiopathology
Larynx / physiopathology*
Prospective Studies
Reflex / physiology*
Reflex, Abnormal / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Randomized, double blind, placebo controlled trial on the safety and efficacy of continuous intratym...
Next Document:  Bile acids identified in middle ear effusions of children with otitis media with effusion.