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Fibrin adhesives have been advocated as a protective seal in colonic anastomosis to prevent leakage. In order to assess the effect of fibrin glue sealing we compared the healing of sutured colonic anastomosis in the rat (group 1) with the addition of human-derived fibrin sealant (group 2). As a control for a possible reaction to foreign protein, in group 3 the sutured anastomosis was sealed with specially prepared rat fibrin adhesive. On days 2, 4 and 7, ten animals in each group were killed. Adhesion formation was scored and the in situ bursting pressure was measured. The collagen concentration and degradation were estimated by measuring hydroxyproline. Adhesion formation was significantly increased in groups 2 and 3 compared with the control group. On days 2 and 7 the bursting pressure was not different between the groups. On day 4 the bursting pressure in groups 2 and 3 was significantly lower than in group 1 (P less than 0.001). These findings correspond with the results of collagen measurements. On day 4 the concentration of hydroxyproline was significantly reduced in groups 2 and 3. Histological examination showed infiltration of neutrophilic granulocytes into the sealant on days 2 and 4; on day 7 the sealant had vanished. From these results it is concluded that fibrin sealing of the colonic anastomosis in the rat does not improve healing, as demonstrated by bursting pressure and hydroxyproline concentration. On the contrary, it seems to have a negative influence.

In a series of experiments, Klebsiella pneumoniae was inoculated intratracheally into rats and mice, and the temperature of the animals was recorded twice daily using microchip transponders. Transponders are interrogated by radio frequencies and were implanted either subcutaneously or intraperitoneally. The microchip temperatures were compared with rectal temperatures taken at the same time. The purpose of the experiments was (a) to investigate the practicability and reliability of the ELAMS for temperature recording; (b) to compare values given by subcutaneously or intraperitoneally implanted transponders with rectal temperatures; and (c) to determine a 'temperature-cut-off point' as an alternative for 'death of the animal' as an end point for the experiment. The results showed that the ELAMS was easy to operate and no important drawbacks in the use of the system were observed. The temperatures generated by the transponders implanted subcutaneously and intraperitoneally did not differ significantly from rectal temperatures. In two out of three experiments on rats, it was shown that when the temperatures reached values below 36 degrees C, the median survival time of the animals was 24 h. In the one experiment on mice the same median survival time was observed at 36 degrees C. In one experiment using rats, however, the disease was so acute that death occurred before any temperature drop was seen. The results show that when a 36 degrees C cut-off point is used instead of the time of death in this particular animal model, the statistical analysis was not altered, but that it would spare animals further suffering for approximately 24 h. The argument that measuring body temperature is a laborious job and stressful to the animals is overcome when the ELAMS system is used.

Microsurgeons suspect that cigarette smoking reduces the survival of free vascularized flaps and replantations, but this has never been proven. This experimental study investigates the effect of smoking on free-flap survival. A fasciocutaneous epigastric flap was used in 30 rats as a free flap and in 30 rats as a pedicled flap. Of each group, 10 rats were smoked 6 weeks before and 2 weeks after surgery, 10 rats were smoked only 6 weeks before surgery, and 10 rats underwent the sham smoking procedure. Also, a distally based dorsal skin flap was cut in all rats, representing a random vascularized flap. Vitality and size of both flaps and patency of the vascular anastomoses were assessed 14 days after surgery. The epigastric flaps were monitored by laser Doppler flowmetry and thermometry during the experiment. Survival of the free vascularized epigastric flaps was significantly lower in smoking rats. All pedicled flaps except one survived. The epigastric flaps only necrosed or survived completely, exactly correlating to the patency of the vascular anastomoses. The mean surviving area of the dorsal flaps was best for nonsmoking rats, worse for only preoperatively smoking rats, and worst for preoperatively and postoperatively smoking rats. The differences were statistically significant. Postoperative laser Doppler flow differed significantly between surviving and dying flaps, affirming the value of laser Doppler flow monitoring in microvascular surgery. In conclusion, this study proves that smoking of cigarettes is detrimental to the survival of free vascularized flaps.

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