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Since allogeneic transplantation of extremities can only be considered if uneventful long-term survival and functional recovery can be achieved, a series of 12 transplantations of the radial side of the hand were performed in rhesus monkeys so that these factors could be assessed. The transplant incorporated the first ray of the hand in conjunction with the radial forearm flap. Graft survival times varied from 21 to 179 days. Ten of 12 transplants showed rejection. In 2 of the 10, rejection could be reversed. Immunosuppressive therapy consisted of cyclosporin A, prednisone, monoclonal antibodies, and preoperative third-party blood transfusions. Monitoring of the microcirculation of the allograft could not provide a predictive value for transplant rejection. The first clinical signs of sensory and motor function recovery were detected after an average of 42 and 44 days, respectively. Indefinite uneventful allograft survival could not be established. Major complications such as sepsis, shock, and lymphoma development leading to death were encountered. The model, however, is technically feasible, and the results for functional recovery under immunosuppression are promising.

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Radial arterial pressure can significantly underestimate central aortic pressure in the postcardiopulmonary bypass (post-CPB) period. At the study institution, routine monitoring of perioperative arterial pressure in adult patients undergoing cardiac surgery is performed with a long radial artery catheter with the distal end positioned in the subclavian artery. In 68 patients presenting for elective cardiac surgery, both a conventional short radial artery catheter and a contralateral long radial artery catheter were placed. Analysis of radial and subclavian arterial pressures post-CPB in the first 47 patients showed average maximum differences of 7 mm Hg systolic and 4 mm Hg mean. In 15% of patients, the differences were clinically significant (greater than 20 mm Hg systolic and/or greater than 14 mm Hg mean). In 28 patients, central aortic pressure was measured post-CPB, and subclavian artery pressure was found to be an excellent estimator of central aortic pressure. There were no significant complications related to using long radial artery catheters in the 68 patients who were followed prospectively. Monitoring subclavian arterial pressure by percutaneous insertion of a long radial artery catheter provides a reliable estimation of central aortic pressure, even in patients with significant radial artery-to-central aortic pressure gradients post-CPB.

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A new concept in monitoring systemic oxygenation that includes the effect of changes in oxyhemoglobin dissociation curve (ODC) has been introduced. Using the S35 (saturation of hemoglobin at PO2 = 35 mmHg), real arterial available oxygen content (CavlO2) can be calculated being the maximum amount of oxygen that can be extracted from hemoglobin before oxygen diffusion into tissue becomes compromised and oxygen uptake (VO2) may decrease. The relation between VO2 and CavlO2 expressed by the extraction ratio of the arterial available oxygen content (ERav) gives a realistic indices of oxygen supply in relation to oxygen consumption. In the present study, during extracorporeal circulation (ECC), a severe shift to the left of the ODC could be observed. THe classic parameters for monitoring systemic oxygenation as mixed venous saturation (Sv-O2) and extraction ratio (ER) did not change. The S35 increased because of the shift to the left of the ODC with consequent decrease in CavlO2. The ERav reached critical values during ECC together with hemodilution and hypothermia. A severe decrease in mixed venous PO2 (Pv-O2) was also observed. The authors conclude that besides Pv-O2, the S35, the CavlO2 and especially the ERav are of value in monitoring the systemic oxygenation during hypothermic ECC.

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The analgesic effect of tramadol was studied in the rat using tail flick and hot plate tests following intrathecal and subcutaneous administrations. Tramadol had only a short-lasting analgesic effect (20 min) on intrathecal administration which may be due to rapid removal from the subarachnoid space. Its analgesic effects were antagonized by pretreatment with naloxone. It seems that the opiate system may involve in the analgesic effect of tramadol, while the noradrenergic, serotonergic and cholinergic systems may play a modulating role.

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Up to December 1980 we performed 21 Fontan operations: 8 for tricuspid atresia and 13 for a functional monoventricle. Although palliative, the operation is currently a good method of treating tricuspid atresia. In our experience, the use of a sufficiently large atriopulmonary valved conduit assures a more satisfactory immediate postoperative hemodynamic result than the atriobulbar non-valved connection (RA-infund. tunnel). Good results can be obtained by a modified Fontan operation in patients with a monoventricle. However, with this malformation, very careful preoperative selection of patients is necessary with special regard to pulmonary vascular resistance. The connection between the right atrium and pulmonary artery was established by a valved conduit in 15 patients; no valve was incorporated in the other 6 patients. The largest prostheses gave the best immediate postoperative hemodynamic results. Two patients with monoventricle were successfully reoperated for persistent right-left shunt. The 13 patients so far followed up for at least a year show definite improvement as compared with their preoperative condition. Late complications from the valved prostheses have not been observed so far.

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The effects of dexamethason (DM) on the postoperative course of coronary artery bypass have been investigated in a double blind study. Twenty patients receiving dexamethason 1 mg/kg body weight intravenously (IV) before cardiopulmonary bypass are compared with a control group of 20 patients receiving placebo. In the treated group core temperature remained normal (maximum 37.6 +/- 0.5 degrees C) while in the control group the patients regularly developed fever (39.0 +/- 0.7 degrees C; p less than 0.01). In the DM-treated group a significantly higher blood pressure, and a lower incidence of rhythm disorders were found. There was a marked difference in the fluid requirements between the 2 groups. Without DM the fluid balance was 2,300 cc positive at the end of the study, in the treatment group this excess was only 1,000 cc (p less than 0.001). Dexamethason treatment also led to higher urine output (130 cc/hr, vs. 85 cc/hr). Although the arterial oxygen tension was higher in the treated group, no patient developed respiratory insufficiency in the control group. The post-pump syndrome is re-evaluated and possible mechanisms are discussed.

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