Thromboelastographic evaluation of mini-dose heparin in minor surgical procedures.

Five dogs weighing approximately 10 kg were anesthetized with pentobarbital sodium 30 mg/kg intravenously (IV) and an initial sample of blood was drawn by jugular venipuncture for control values of thromboelastography (TEG). Immediately after venipuncture, mini-dose heparin (80 units/kg) was administered subcutaneously. One hour later, 0.5 ml blood was obtained by (A) jugular venipuncture for TEG, and an indwelling catheter immediately introduced into a femoral vein by cut-down. Blood samples for TEG were obtained via cut-down at (B) 15 min (C) 30 min, and (D) 60 min after cut-down. Low-dose heparin had no effect on the hemostatic parameters as measured by TEG and did not prevent the accelerated coagulation associated with surgery.

Paradoxical effect of burns in diabetic mice.

Since the microcirculation is impaired in diabetes and since burn injury is associated with microvascular thrombosis, the purpose of this study was to determine whether diabetes increases the severity of burns. Swiss white mice were made diabetic with alloxan, and control animals received saline. One week later, animals with over 2000 mg/dl urine sugar and the control animals were anesthetized and burned uniformly on the back with a steel disc at 100 C for 10 sec. At 24 hr, burn severity was evaluated on a scale of 0 to 4 using gross and microscopic criteria. The mean burn severity of the diabetic mice was 0.80 +/- .15 and that of the control mice was 3.22 +/- .09 at 24 hr (P less than 0.001.). At 5 days, the differences of the burn severity between the two groups were still significant, but 5/10 (50%) of the diabetic mice and none of the control mice died. In diabetic mice, through burn severity appears mild in the wound, the mortality is high. Therefore, the criteria for initial evaluation of the diabetic with burns need to be reassessed.

The effect of age on severity of murine burns.

There is a higher mortality in elderly subjects with burns. Whether the same amount of heat will cause a greater degree of thermal injury in elderly subjects and thus account, in part at least, for this increased mortality has not been determined and was, therefore, the purpose of this study. Swiss white mice, 1-year-old (elderly) and 3-months-old (young) were anesthetized with pentobarbital sodium and burned uniformly on a depilated area of the back with a steel disc at 100 F for 10 seconds (10% body burn). Burn severity was evaluated in a blinded manner by gross and microscopic criteria at 1, 2, and 4 days postburn. The mean burn severity 1 day postburn was significantly less in the elderly mice compared with the young mice (1.72 versus 3.22, (P less than 0.001). On the 2nd and 4th days postburn, no differences were noted in the degree of burn severity between the two groups. The early apparent diminished burn severity in the elderly mice was unexpected. Possible mechanisms to account for this difference in the old animals may relate to decreased cutaneous microcirculation, alteration in chemical composition of the skin, and the effects of thromboxane A2 and prostaglandin I2. The clinical relevance of these findings concerns the need for more careful clinical management with intentional overassessment of the initial degree of the thermal damage.