Periodic breathing induced on demand in the awake newborn lamb.
Canet, Emmanuel, Jean-Paul Praud, and Michel A. Bureau.
Unit[acute]e de Recherche Pulmonaire, D[acute]epartement de
P[acute]ediatrie, Universit[acute]e de Sherbrooke, Sherbrooke
(Qu[acute]ebec) Canada J1H 5N4
APStracts 3:0487A, 1996.
Spontaneous periodic breathing, although a common feature in fullterm
and preterm human infants, is scarce in other newborn mammals. The
aim of this study was to induce periodic breathing in lambs. Four 10
-day-old, and two less-than 48-hour-old awake lambs were instrumented
with jugular catheters connected to an extracorporeal membrane lung
aimed at controlling PaCO2. PaO2 was set and maintained at the
desired level by changing inspired oxygen fraction and providing O2
through a small catheter into the "apneic" lung. At a
critical PaO2/PaCO2 combination, the four 10-day-old lambs exhibited
periodic breathing that could be initiated, terminated, and
reinitiated on demand. In the two-day-old lambs with low
chemoreceptor gain, periodic breathing was hardly seen, regardless of
the trials done to find the critical PO2/PCO2 combination. We
conclude that periodic breathing can be induced in lambs and depends
on critical PaO2/PaCO2 combinations and maturity of the
chemoreceptors.
Received 1 March 1995; accepted in final form 3 October 1996.
APS Manuscript Number A230-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996