sodium-pertechnetate-tc-99m and Shock--Septic

The aim of the present study was to explore lung microvascular leakage of protein and water in a feline model of septic shock, using a double isotope technique with external gamma camera detection and gravimetric lung water measurements. The experiments were performed on artificially ventilated cats. One group of cats (n = 8) was given an infusion of live Escherichia coli bacteria, and another group (n = 5) served as a control group receiving saline. Plasma transferrin was radiolabeled in vivo with indium-113m-chloride, and erythrocytes were labeled with technetium-99m. The distribution of these isotopes in the lungs was continuously measured with a gamma camera. A normalized slope index (NSI) was calculated, indicative of the transferrin accumulation corrected for changes in local blood volume that reflect protein leakage. In the septic group there was a protein leakage after bacterial infusion, with a NSI of 39 x 10(-4) +/- 5 x 10(-4) min-1 (mean +/- SEM), and the PaO2 diminished from 21 +/- 1 to 9.5 +/- 1 kPa. In control cats a slight protein leakage with a NSI of 9 +/- 10(-4) +/- 2 x 10(-4) min-1 was detected, probably caused by the operative procedure, but PaO2 did not change. Wet-to-dry-weight ratios of postmortem lungs were not significantly different between the groups. It was concluded that an intravenous infusion of live E. coli bacteria induces a lung capillary protein leakage without increased lung water and a concomitantly disturbed gas exchange.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cats; Disease Models, Animal; Escherichia coli Infections; Extravascular Lung Water; Gamma Cameras; Indium; Indium Radioisotopes; Lung; Microcirculation; Organ Size; Proteins; Radioisotope Dilution Technique; Radionuclide Imaging; Shock, Septic; Sodium Pertechnetate Tc 99m; Transferrin

Septic shock constitutes a great threat to patients undergoing major abdominal surgery and also to trauma patients. The current state of knowledge on pathophysiological mechanisms in septic shock is not fully known. The aim of this study was to develop an experimental model that resembled the clinical situation and allowed the exploration of central and peripheral vascular mechanisms in endotoxic shock. Seven anesthetized sheep (weighing 30-45 kg) were provoked to lethal endotoxic shock by intravenous injection of 3 mg/kg bodyweight Escherichia coli endotoxin. The arterial pressure was monitored. Serial radionuclide images of the chest and abdomen were recorded after injecting technetium-99m-labeled RBC's. The volumetric (blood) alterations of liver, spleen, kidney, heart, and lungs, as well as peripheral muscle were measured. Prior to injection of endotoxin base-line data were obtained. Two to 4 minutes after injection, spleen volume decreased by -36% (mean) followed by a slow restoration; the left ventricular volume and kidneys increased by a maximum of 10-15%, while the liver volume increased by 38% of initial volume.

Topics: Animals; Blood Volume Determination; Erythrocytes; Radionuclide Imaging; Sheep; Shock, Septic; Sodium Pertechnetate Tc 99m