Objective:To investigate whether an increased ileal-mucosal-arterial PCO2 g
ap (Delta PCO2) during hyperdynamic porcine endotoxemia is associated with
impaired villus microcirculation,
Design: Prospective, randomized, controlled, experimental study.
Setting: Animal research laboratory.
Animals: Twenty-two domestic pigs.
Interventions: After baseline measurements, anesthetized and ventilated pig
s received continuous i.v. endotoxin (ETX, n = 12) for 24 h or placebo (SHA
M, n = 10).
Measurements and results: Before, as well as 12 and 24 h after, the start o
f endotoxin or saline portal venous blood now (Q,v, ultrasound flow probe)
and lactate/pyruvate ratios (LIP), the ileal-mucosal-arterial Delta PCO2 (f
iberoptic sensor) and bowel-wall capillary hemoglobin Or saturation (%Hb-O-
2-cap, remission spectrophotometry) were assessed together with intravital
video records of the ileal-mucosal microcirculation (number of perfused/het
erogeneously perfused/unperfused villi) using orthogonal polarization spect
ral imaging (CYTOSCAN A/R) via an ileostomy At 12 and 24 h endotoxin infusi
on, about half of the evaluated villi were heterogeneously or unperfused wh
ich was paralleled by a progressive significant increase of the ileal-mucos
al-arterial Delta PCO2: and portal venous LIP ratios? whereas Q(PV) as well
as both the mean % Hb-O-2-cap and the %Hb-O-2-cap frequency distributions
remained unchanged. By contrast, in the SHAM-group, mucosal microcirculatio
n was well-preserved, and none of the other parameters were influenced.
Conclusions: We conclude that an increased ileal-mucosal-arterial Delta PCO
2 during porcine endotoxemia is related to impaired villus microcirculation
. A putative contribution of disturbed cellular oxygen utilization resultin
g from ''cytopathic hypoxia" may also assume importance.