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Laryngeal Stimulation by an Acid Solution in the Pre-term Lamb

  • Marie St-hilaire
  • Nathalie Samson
  • Charles Duvareille
  • Jean-Paul Praud
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 605)

In a mature organism, the contact between various liquids and the laryngeal mucosa triggers lower airway protective responses (cough, swallowing, arousal). These laryngeal chemoreflexes (LCR) are essential for preventing aspiration. In contrast, previous studies showed that LCR are responsible for apnea and bradycardia in the neonatal mammal. Consequently, LCR, especially when triggered by acid gastrolaryngeal reflux, are deemed responsible for some apneas of prematurity and many life-threatening events of infancy and, probably, for some cases of sudden infant death syndrome. Recently, we have revisited LCR in full-term lambs during quiet sleep. Our results showed that the LCR triggered by HCl (pH 2), mimicking the acid component of an acid gastro-oesophageal reflux, were consistently like the mature LCR reported in adult mammals, without significant apneas and bradycardias (St-Hilaire 2005). These results prompted us to question whether premature birth alters LCR. Results show that LCR triggered in pre-term lambs by both saline and HCl are much more marked and clinically relevant than the ones observed in fullterm lambs. Indeed, life-threatening responses to HCl, including repetitive apneas for more than 90 seconds, severe desaturation and bradycardia, were observed in 2 lambs at postnatal day 7 (D7). In addition, LCR were significantly blunted at D14. In conclusion, HCl can trigger potentially dangerous LCR in pre-term lambs at D7, suggesting that LCR in response to acid gastrolaryngeal refluxes are likely involved in some apnea/bradycardia/desaturation in pre-term infants, before they reach a post-conceptional age equivalent to full gestation.

Keywords

Quiet Sleep Laryngeal Mucosa Mature Organism Severe Desaturation Subglottal Aspiration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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© Springer 2008

Authors and Affiliations

  • Marie St-hilaire
  • Nathalie Samson
  • Charles Duvareille
  • Jean-Paul Praud

There are no affiliations available

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