Endotracheal Measurement of Thyroarytenoid Activity in Newborn Lambs

Laryngeal control of expiratory airflow is a principal means by which the newborn establishes and maintains absolute lung volume. Specifically, retardation of expiratory airflow is effected by the major adductors of the larynx, the thyroarytenoid (TA) muscles. The long-term aim of this research is to determine if monitoring TA activity can be used to optimize absolute lung volume during artificial ventilation of the human baby. This initial study, performed in unanesthetized chronically instrumented newborn lambs, tests the hypothesis that the timings of the onsets, peaks and durations of TA activity recorded by the endotracheal electrode are equivalent to those measured by a surgically placed intramuscular electrode. Endotracheal measurement of TA activity is accurate and specific and can monitor changes in airway pressure and lung volume.