thiopental and Calcinosis

The authors prospectively investigated the ability of thiopental to decrease neuropsychiatric complications as a consequence of open-ventricle operations requiring cardiopulmonary bypass. Eighty-nine randomly assigned patients received sufficient thiopental to maintain electroencephalographic silence throughout the period from before atrial cannulation to termination of bypass. These patients received an average of 39.5 mg/kg of thiopental, while 93 control patients received only fentanyl. On the first postoperative day, five thiopental (5.6%) and eight control (8.6%) patients exhibited clinical neuropsychiatric abnormalities. By the tenth postoperative day, all neuropsychiatric dysfunction had resolved in the thiopental group but persisted in seven (7.5%) control patients (P less than 0.025). The incidence of complications was significantly related to calcification of replaced valves, aortic valve replacement, advanced age, and prolonged bypass, but not to low blood pressure during perfusion. The authors believe their data are consistent with embolism as the most important cause of sensory-motor neurologic dysfunction following cardiopulmonary bypass. The data also provide evidence that thiopental in sufficient dosage can reduce the clinical consequences of these events. This is the first demonstration of cerebral protection by a barbiturate in humans.

Topics: Age Factors; Aged; Barbiturates; Blood Pressure; Calcinosis; Cardiopulmonary Bypass; Delusions; Electroencephalography; Female; Hallucinations; Heart Valve Prosthesis; Humans; Male; Memory Disorders; Middle Aged; Myocardial Contraction; Neuropsychological Tests; Postoperative Complications; Sleep Stages; Thiopental; Time Factors

To develop tissue valves for prolonged use in the cardiovascular system, the complicated process of surface induced calcification must be better understood. Calcification was examined for 60 days on glutaraldehyde treated bovine pericardium (GABP) and enzyme extracted tissues fixed in glutaraldehyde (GATBP) incubated in metastable solutions of calcium phosphate, and the roles of aspirin and persantine in conjunction with vitamins C, B, or E, gentamycin (antibiotic), or pentothal sodium (anesthetic) in the medium were examined. Further, the diffusion of calcium across the GATBP was evaluated using a diffusion cell with 2 compartments. Pericardial calcification was also observed using scanning electron microscopy (SEM) techniques. It seems that the examined antiplatelet agents can modify the pericardial surfaces and subsequently their mineralization processes (GATBP, 31.7 micrograms/mg tissue; in the presence of 5 mg% vitamin C, 13.1 micrograms/mg tissue; in 1.5 mg% aspirin, 17.2 micrograms/mg tissue; and 1 mg% gentamycin, 14.8 micrograms/mg tissue) on exposure with the metastable calcium phosphate solution for 60 days. In addition, these agents may modify calcium transport and interfere with the adsorption at the surface, hence reducing calcium nodulation on GATBP. Scanning electron micrographs also revealed a reduction in calcium deposition on the pericardium due to these antiplatelet agents. It may be hypothesized that the influx of calcium on GATBP may be due to the cellular components or the involvement of plasma proteins like the fibrinogen molecule. The exact mechanism of these changes in the calcification of the pericardium are still unknown. From these in vitro findings, it appears that a combined vitamin therapy with low doses of aspirin may be beneficial for platelet suppression and thereby for prevention of thrombosis and calcification. However, more in vivo studies are needed to develop applications.

Topics: Anesthetics, Intravenous; Animals; Anti-Bacterial Agents; Aspirin; Bioprosthesis; Calcinosis; Cattle; Dipyridamole; Gentamicins; Glutaral; In Vitro Techniques; Pericardium; Platelet Aggregation Inhibitors; Thiopental; Tissue Fixation; Vitamins