J Korean Neurosurg Soc.  1995 Dec;24(12):1463-1468.

Brain Stem Blood Flow During Hypercapnia, Hypocapnia, Hypoxia, and Hemorrhagic Hypotension in Newborn Piglet

• Kim TY

Abstract

Changes of brain stem blood flow(BBF) during physiologic stimulation, such as hypoxia, hypo-and hypercapnia, and hemorrhagic hypotension, were studied by hydrogen clearance technique through closed clival window in the brain stem of nerborn piglet. Induction of moderate hypercapnia(PaCO2=65.4+/-2.11mmHg) caused prominent increases in BBF(354+/-39%;p<0.0001). Conversely, in response to moderate hypocapnia(PaCO2=23.9+/-0.64mmHg), a significant decreases in BBF(-30.38+/-3.22%;p<0.0001) was observed. During severe hypoxia(PaO2=3.7+/-1.4mmHg)moderate increases in BBF(161+/-51.4%;p=0.005) occurred. Interestingly, in response to systemic hypotension(Mean Arterial Blood Pressure=34+/-0.7mmHg), a nonsignificant reduction of BBF was recorded(-14+/-10%;p=0.240). These findings suggest that CO2 reactivity of newborn piglet posterior circulation is high;however, hypoxic reactivity is relatively moderate, and BBF is autoregulated during systemic hypotension.

Keyword

Brain stem; Blood flow; New-born piglet; CO2 reactivity; Hypoxia; Hypotension

MeSH Terms

Anoxia*
Brain Stem*
Brain*
Humans
Hydrogen
Hypercapnia*
Hypocapnia*
Hypotension*
Infant, Newborn*
Hydrogen