Document Detail

Effects of halothane, ketamine, propofol and alfentanil anaesthesia on circulatory control in rabbits.
MedLine Citation:
PMID:  2078906     Owner:  NLM     Status:  MEDLINE    
1. We have made a within-rabbit comparison of the effects of four general anaesthetic regimens on the haemodynamic response to acute reduction in central blood volume and on baroreflex control of heart rate. 2. Acute haemorrhage was simulated by gradually inflating a cuff on the inferior vena cava in order to cause cardiac output to fall at a constant rate of 8.5%/min while the responses of systemic vascular resistance, arterial pressure and heart rate were measured. The full range of the baroreceptor-heart rate reflex was elicited by inflating aortic and vena caval cuffs. These indices of circulatory control were repeatedly measured within five protocols, to which each rabbit was exposed in randomized order. 3. In each protocol the rabbit was first studied unanaesthetized. Then a small dose of thiopentone sodium was given (16 mg/kg). In the four main protocols the rabbit was then intubated and ventilated, first with 100% oxygen and then with 50% nitrous oxide, during administration of one of four anaesthetic agents. These were halothane (2.0 and 2.5%), ketamine (2.5 mg/kg per min), propofol (0.83 and 1.25 mg/kg per min) and alfentanil (2.5 and 3.33 micrograms/kg per min). In a sham protocol the effects of 100% oxygen, then those of 50 and 75% nitrous oxide, were studied while the rabbit remained conscious. 4. In unanaesthetized rabbits, in the presence or absence of nitrous oxide, the normal biphasic haemodynamic response to simulated haemorrhage occurred. The first, vasoconstrictor, phase was attenuated by halothane, ketamine and propofol, so that arterial pressure fell more steeply than normal. Not only was the vasoconstrictor phase unaffected by alfentanil but it was extended, so that arterial pressure remained at a normal level even when cardiac output had fallen by 59%. This effect of alfentanil appeared to be mediated centrally, since it could be reproduced by injecting small doses (1.5-7.5 micrograms) into the fourth ventricle. All four anaesthetic agents and nitrous oxide attenuated the baroreceptor control of heart rate. The effect was least with nitrous oxide and alfentanil, greatest with halothane.
A F Van Leeuwen; R G Evans; J Ludbrook
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  17     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  1990 Nov 
Date Detail:
Created Date:  1991-04-26     Completed Date:  1991-04-26     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  781-98     Citation Subset:  IM    
Department of Surgery, University of Melbourne, Parkville, Victoria, Australia.
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MeSH Terms
Alfentanil / pharmacology
Anesthetics / pharmacology*
Blood Pressure / drug effects*
Blood Volume*
Halothane / pharmacology
Heart Rate / drug effects
Hemorrhage / physiopathology*
Ketamine / pharmacology
Nitrous Oxide / pharmacology
Pressoreceptors / physiopathology
Propofol / pharmacology
Reg. No./Substance:
0/Anesthetics; 10024-97-2/Nitrous Oxide; 151-67-7/Halothane; 2078-54-8/Propofol; 6740-88-1/Ketamine; 71195-58-9/Alfentanil

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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