Linked Life Data

3205609

Source:http://linkedlifedata.com/resource/pubmed/id/3205609

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1989-2-9
pubmed:abstractText
To determine the factors regulating cardiac output in newborn lambs and to examine the effects of age after birth, we altered heart rate, afterload, preload, and myocardial contractility in eight younger lambs, 5 to 13 days old, and seven older lambs, 15 to 36 days old. To control heart rate, we ablated the atrioventricular node by injecting formalin into the region of the node, and paced the right ventricle at a baseline heart rate of 200 beats/min. After the lambs recovered from surgery, we performed two protocols. In the first protocol we assessed the effects of changing heart rate by pacing the ventricle at various rates. We also examined the effect of altering afterload and preload at a fixed heart rate: afterload was increased by infusing phenylephrine and decreased by infusing nitroprusside. Preload was increased by infusing blood or 0.9% NaCl solution over 2 min. In the second protocol, we increased myocardial contractility by infusing isoproterenol at a fixed heart rate. Increasing heart rate above baseline levels caused no significant increase in cardiac output in the younger lambs (3.9 +/- 4.0%, mean +/- SD), and only small increases in the older lambs (11.4 +/- 6.7%). Decreasing heart rate, however, resulted in a progressive decrease in cardiac output in both groups of lambs. Decreasing afterload caused no significant increase in cardiac output in the younger lambs (1.4 +/- 14.0%) and only a small increase in the older lambs (11.1 +/- 1.9%).(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0031-3998
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
577-82
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Regulation of cardiac output with controlled heart rate in newborn lambs.
pubmed:affiliation
Department of Pediatrics, University of California, San Francisco 94143.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't