Active glottal closure during anoxic gasping in lambs

The present study was aimed at assessing laryngeal dynamics and their conse quences during anoxic gasping in ketamine-sedated lambs. We first verified that the glottis was closed between gasps during anoxic gasping in seven ch ronically instrumented lambs, aged 11-15 days. Recording of glottal constri ctor muscle electrical activity, subglottal pressure and lung volume, toget her with endoscopic observation. confirmed the presence of active glottal c losure with maintenance of a high lung volume between gasps. Secondly, we t ested whether maintenance of a high lung volume between gasps improved auto resuscitation efficiency. Six sedated lambs aged 8-11 days underwent two an oxic runs, including one with an open tracheostomy to prevent maintenance o f a high lung volume. Access back to air was allowed for gasping. No signif icant difference was found in time to eupnea resumption, hemodynamic parame ters or arterial blood gases. We conclude that a high lung volume is active ly maintained by glottal closure between anoxic gasps in sedated lambs. Fur ther studies are however needed to define the importance of laryngeal dynam ics during gasping. (C) 2001 Elsevier Science B.V. All rights reserved.