CJA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text (PDF)
Right arrow Submit a scholarly reply
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by ONG, B. Y.
Right arrow Articles by PALAHNIUK, R. J.
Right arrow Search for Related Content
PubMed
Right arrow Articles by ONG, B. Y.
Right arrow Articles by PALAHNIUK, R. J.

Canadian Journal of Anesthesia, Vol 33, 5-9, Copyright © 1986 by Canadian Anesthesiologists' Society

Acidemia Impairs Autoregulation of Cerebral Blood Flow in Newborn Lambs

B. Y. ONG MD FRCPC1, R. GREENGRASS MD FRCPC2, D. BOSE MD PHD2, G. GREGORY MD2, and R. J. PALAHNIUK MD FRCPC2

1 Departments of Anesthesia, Internal Medicine and Pharmacology, University of Manitoba, Winnipeg, and the Department of Anesthesia, University of California, San Francisco, California
2 Departments of Anesthesia, Internal Medicine and Pharmacology, University of Manitoba, Winnipeg, and the Department of Anesthesia, University of California, San Francisco, California

Address correspondence to: Dr. B.Y. Ong, Department of Anesthesia, Health Sciences Centre, 700 Wiliam Avenue, Winnipeg, Manitoba, Canada, R3E 0Z3.

Cerebral blood flow (CBF) and autoregulation of cerebral blood flow were assessed in newborn lambs before and after inducing metabolic acidemia. CBF was measured by xenon washout and autoregulation by the change in CBF after increasing mean arterial pressure (MAP) 30 per cent with 0.02 per cent phenylephrine hydrochloride. After surgical preparation, stabilization, and demonstration of the presence of autoregulation, six lambs received 10 mg·kg-1 of lactic acid intravenously over 30 minutes. Arterial pH decreased from 7.35 ± 0.01 (mean ± SEM) during the control period to 6.96 ± 0.02 (p < 0.01) at the end of the lactic acid infusion. Arterial blood gases, MAP's, and heart rates did not change. Prior to lactic acid infusion, CBF before and after raising MAP were 53 ± 3 ml/100 g/min and 56 ± 4 ml/100 g/min respectively. After lactic acid infusion, CBF increased from 54 ±2 ml/100 g/min to 62 ± 3 ml/100 g/min (p < 0.05) following phenylephrine induced rise in MAP. Five control lambs showed no significant change in any of these variables, including CBF, over the same time periods. These data indicate that metabolic acidosis per se does not alter CBF, but that metabolic acidosis impairs cerebral vascular autoregulation in hyperoxic lambs. Similar changes in human neonates might result in intracranial haemorrhage.

Key Words: BRAIN: cerebral autoregulation, cerebrovascular circulation • ACID-BASE EQUILIBRIUM: acidosis






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1986 by the Canadian Anesthesiologists' Society.