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Prolonged active glottic closure after barbiturate-induced respiratory arrest in lambs
J P Praud1, I Kianicka, V Diaz
1Department of Pediatrics, Faculty of Medicine, University of Sherbrooke, Québec, Canada. jp.praud@courrier.USherb.ca
Respiration Physiology
|July 1, 1996
Summary
The glottis actively closes during non-hypocapnic central apnea in lambs, indicating a protective airway response. This active glottic closure occurs with significant decreases in the central drive to breathe.
Area of Science:
- Physiology
- Respiratory Control
- Neonatal Research
Background:
- Previous research demonstrated active glottic closure during hypocapnic central apnea in lambs.
- The mechanism of glottic closure during non-hypocapnic central apnea remained uninvestigated.
Purpose of the Study:
- To determine if the glottis is actively closed during non-hypocapnic central apnea in neonatal lambs.
- To investigate the relationship between glottic closure and central respiratory drive depression.
Main Methods:
- Induction of apnea in 27 lambs (2-30 days old) via sodium pentobarbital injection.
- Measurement of airflow using a facial mask and pneumotachograph.
- Recording of thyroarytenoid muscle electromyographic activity (TA EMG) to assess glottic adductor function.
Main Results:
- Onset of apnea was followed by rapid, continuous TA EMG, indicating active glottic closure.
- Eight lambs exhibited brief inspiratory gasps with abrupt inhibition of TA EMG.
- Continuous TA EMG ceased between 115 and 230 seconds post-apnea onset.
Conclusions:
- The glottis is actively closed during fatal non-hypocapnic central apnea in lambs.
- Active glottic closure appears to be a response to profound depression of central inspiratory drive.