Periodic breathing induced on demand in awake newborn lamb

Canet, Emmanuel, Jean-Paul Praud, and Michel A. Bureau.Periodic breathing induced on demand in awake newborn lamb. J. Appl. Physiol. 82(2): 607-612, 1997.Spontaneous periodic breathing, although a common feature infullterm and preterm human infants, is scarce in other newborn mammals.The aim of this study was to induce periodic breathing in lambs. Four10-day-old and two <48-h-old awake lambs were instrumented withjugular catheters connected to an extracorporeal membrane lung aimed atcontrolling arterial PCO₂(Pa_CO2). ArterialPO₂(Pa_O2) was set and maintained at thedesired level by changing inspiredO₂ fraction and providingO₂ through a small catheter intothe "apneic" lung. At a criticalPa_O2/Pa_CO2combination, the four 10-day-old lambs exhibited periodic breathingthat could be initiated, terminated, and reinitiated on demand. In the2-day-old lambs with low chemoreceptor gain, periodic breathing washardly seen, regardless of the trials done to find the criticalPO₂/PCO₂combination. We conclude that periodic breathing can be induced inlambs and depends on criticalPa_O2/Pa_CO2combinations and maturity of the chemoreceptors.