ABNORMALITIES OF GASTRIC-MUCOSAL OXYGENATION IN SEPTIC SHOCK - PARTIAL RESPONSIVENESS TO DOPEXAMINE

Splanchnic mucosal perfusion abnormalities have been implicated in the development of sepsis and multiorgan failure. We employed reflectance spectrophotometry for direct assessment of the microvascular hemoglob in oxygen saturation (Hbi(o2)) and hemoglobin concentration (rel Hb(co nc)) in the mucosa of the upper gastrointestinal tract. Owing to the h igh recording frequency together with a small catchment volume, assess ment of spatial heterogeneity is enabled. Results were as follows: In healthy controls (n = 7), mean Hbi(o2) was 70.3 +/- 2.1%, with narrow dispersion and near-Gaussian distribution of the histogram. In patient s presenting with hyperdynamic septic shock (n = 15) mean Hbi(o2) was reduced to 51.0 +/- 1.6% in spite of high normal whole-body oxygen del ivery, with tailing of the histogram to severely hypoxic values (18.4% of data < 40%). In parallel, markedly reduced rel Hb(conc), values we re recorded and the standardized intramucosal pH (pHi) was lowered to 7.25 +/- 0.01. Short-term infusion of dopexamine (2 mu g/kg/min) cause d a significant rise in Hbi(o2) and rel Hb(conc), whereas whole-body o xygen uptake and standardized pHi values were not altered. In conclusi on, decreased oxygenation and tissue hemoglobin concentration, with th e appearance of severely hypoxic microdomains, were noted in patients with hyperdynamic sepsis, strongly suggesting pronounced microcirculat ory disturbances in this compartment. The partial responsiveness of th ese abnormalities to dopexamine warrants further elucidation.