THROMBOXANE A2 AND HEMODYNAMIC-BIOCHEMICAL PARAMETERS IN CANINE ENDOTOXIN SHOCK

Prostaglandins participate in the pathophysiology of endotoxin shock; however, their exact role has not yet been clear. In this study, we investigated the role of the proaggregatory vasoconstrictor, thoromboxane A2 (T×A2), an arachidonic acid metabolite, during canine endotoxin shock. The central venous plasma levels of thromboxane B2 (T×B2), the stable metabolite of T×A2, was measured by radioimmunoassay. We also investigated the therapeutic effect of reduced glutathione (GSH), a potential cell-stabilizing sulfhydryl compound, in canine endotoxin shock. Sixty minutes after the intraveous administration of E. coli endotoxin (1 mg/kg), the plasma T×B2 levels were significantly increased from 68.8±49.0 pg/ml to 318.3±117.2 pg/ml (N=5) in the control group and from 67.9±68,4 pg/ml to 222.6±133.2 pg/ ml (N=5) in the GSH (300 mg/kg/hr) group. The levels in the GSH group were somewhat lower than in the control group for 60 to 180 minutes after the injection of endotoxin. Thromboxane A2 value appear not to relate to early thrombocytopenia and pulmonary hypertension but to relate to the change of late coagulopathy and of pulmonary vascular resistance. The administration of GSH suppressed the lactic acidemia significantly, however there was a much more decrease in the mean arterial pressure in the GSH group than in the control group. In addition, there was a tendency to inhibit the increase of the serum β-glucronidase activity in the GSH group

COMPARISON OF HEMODYNAMIC EFFECTS OF MORPHINE, BUTORPHANOL, BUPRENORPHINE AND PENTAZOCINE ON ICU PATIENTS

Morphine and narcotic agonist-antagonists have been used to assist ICU patients in adapting to mechanical ventilation. In this study, 10 mg of morphine and the equipotent doses of synthetic analgesics, 2 mg of butorphanol, 0.6 mg of buprenorphine or 30 mg of pentazocine were administered intravenously to 29 patients requiring a ventilator. Hemodynamic effects on the heart rate, mean arterial pressure (MAP), cardiac index, stroke index, left ventricular stroke work index, mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP) and systemic and pulmonary vascular resistance (PVR) were measured. The hemodynamic effects of the four drugs were mild and not statistically significant except for the reduction in PCWP and the increase in PVR after morphine and the increase in MAP and MPAP after pentazocine administration. These doses of the four drugs could be given safely even in critically ill patients. The hemodynamic effects of these analgesics showed a similarity between the administration of butorphanol and morphine, and between buprenorphine and pentazocine. This study demonstrates that morphine and butorphanol are preferred to the cases with hypertension, increased pulmonary arterial pressure or wedge pressure and that pentazocine and buprenorphine are more suitable for the cases with hypotension or hypovolemia

HEMODYNAMICS IN EXPERIMENTAL ENDOTOXIN SHOCK WITH CONTINUOUS ADMINISTRATION

Experimental endotoxin shock was induced with 4 mg/kg of purified endotoxin by continuous infusion instead of bolus injection in order to simulate the clinical condition. Abrupt decrease in the mean artery pressure and transient increase in the pulmonary artery pressure, which were usually seen in the initial stage accompanying the bolus injection of endotoxin, did not occur with continuous infusion. The superior mesenteric fraction rate of cardiac output (CO) in our study showed an increase, which was different from the small intestinal fraction rate of CO shown by Okada et αl. by the micro-sphere method (MS method) accompanying the bolus injection of endotoxin. These effects might be caused by the difference in the injection method and endotoxin dose. Measurements of the cardiac output, common carotid artery flow, renal artery flow and superior mesenteric artery flow proved that the largest reduction was observed in the renal blood flow