Baroreceptor-mediated compensation for hemodynamic effects of positive end-expiratory pressure
1 American University of the Caribbean School of Medicine, Cupecoy, St. Maarten, Netherland Antilles; 2 Maryland Department of Business and Economic Development, Baltimore 21202; and 3 Departments of Surgery and Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201 The...
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Published in | Journal of applied physiology (1985) Vol. 86; no. 1; pp. 285 - 293 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
Am Physiological Soc
01.01.1999
American Physiological Society |
Subjects | |
Online Access | Get full text |
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Summary: | 1 American University of the
Caribbean School of Medicine, Cupecoy, St. Maarten, Netherland
Antilles; 2 Maryland Department of
Business and Economic Development, Baltimore 21202; and
3 Departments of Surgery and
Physiology, University of Maryland School of Medicine, Baltimore,
Maryland 21201
The roles of
the carotid arterial baroreceptor reflex and of vagally mediated
mechanisms during positive end-expiratory pressure (PEEP) were
determined in pentobarbital-anesthetized dogs with isolated carotid
sinuses. Spontaneously breathing dogs were placed on PEEP (5-10
cmH 2 O) with the carotid sinus
pressure set to the systemic arterial pressure (with feedback) or to a
constant pressure (no feedback). Right atrial volume was measured with
a conductance catheter. With carotid baroreceptor feedback before
bilateral cervical vagotomy, total peripheral resistance increased
( P < 0.01) and mean arterial
pressure decreased ( 9.8 ± 4.3 mmHg) in response to PEEP.
With no feedback after vagotomy, mean arterial pressure decreased to a
greater extent ( 45 ± 6 mmHg,
P < 0.01), and total peripheral
resistance decreased ( P < 0.05) in
response to PEEP. In contrast, cardiac index decreased similarly during PEEP ( P < 0.01) for all baroreceptor
and vagal inputs. This response comprised a decrease in the passive
phase of right ventricular filling ( P < 0.01) that was not matched by the estimated increase in active
right atrial output. Although the carotid baroreceptor reflex and
vagally mediated mechanisms elicit vasoconstriction to compensate for
the effects of PEEP on the arterial pressure, these processes fail to
defend cardiac output because of the profound effect of PEEP on the
passive filling of the right ventricle.
carotid arterial stretch receptor; cardiac output; conductance
catheter; right atrial volume; total peripheral resistance; vagotomy |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/jappl.1999.86.1.285 |