Perfusion Pressure
Manipulation in Porcine Sepsis: Effects on Intestinal
Hemodynamics
A. KROUŽECKÝ, M. MATĚJOVIČ, J. RADĚJ, R. ROKYTA
JR., I. NOVÁK
Intensive Care Unit, First Medical Department, Faculty of
Medicine and Teaching Hospital, Charles University, Plzeň, Czech
Republic
Received date June 22, 2005
Accepted date November 9, 2005
On-line available December 12, 2005
Summary
Limited information is available about selection of the
threshold for arterial blood pressure in critically ill
patients, particularly in sepsis when normal organ blood flow
autoregulation may be altered. The present experimental study
investigated whether increasing perfusion pressure using
norepinephrine in normotensive hyperdynamic porcine bacteremia
affects intestinal macro- and microcirculation. Nine pigs
received continuous i.v. administration of Pseudomonas
aeruginosa (PSAE) to develop hyperdynamic, normotensive (mean
arterial pressure [MAP] 65 mm Hg) sepsis. Norepinephrine was
used to achieve 10-15 % increase in MAP. Mesenteric arterial
blood flow (Qgut), ileal mucosal microvascular perfusion
(LDFgut) and ileal-end-tidal PCO2 gap (PCO2 gap) were measured
before norepinephrine, after 60 min of norepinephrine infusion
and 60 min after norepinephrine infusion had been discontinued.
During a 12 h period of PSAE infusion all pigs developed
hyperdynamic circulation with significantly decreased MAP.
Although the mesenteric blood flow remained unchanged, infusion
of PSAE resulted in a gradual fall of ileal microvascular
perfusion, which was associated with progressively rising PCO2
gap. Norepinephrine which induced a 10-15 % increase in
perfusion pressure (i.e. titrated to attain near baseline values
of MAP) affected neither Qgut nor the intestinal blood flow
distribution (Qgut/CO). Similarly, norepinephrine did not change
either LDFgut or PCO2 gap. In this hyperdynamic, normotensive
porcine bacteremia, norepinephrine-induced increase in perfusion
pressure exhibited neither beneficial nor deleterious effects on
intestinal macrocirculatory blood flow and ileal mucosal
microcirculation. The lack of changes suggests that the gut
perfusion was within its autoregulatory range.
Key words
Sepsis • Shock • Perfusion pressure • Microcirculation •
Norepinephrine
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