Platelet changes during heart surgery with extracorporeal circulation

The changes in the number of platelets during anesthesia and operation were evaluated in 24 patients (8 females and 16 males) scheduled for cardiac surgery with cardiopulmonary bypass. There was a significant (p less than 0.05) thrombopenia at the beginning of perfusion, which persisted 60 minutes after the end of cardiopulmonary bypass. There were no significant differences when these changes were evaluated depending on the type of oxygenator, the need for transfusion or the duration of cardiopulmonary bypass. There was a reduction in the platelet count at the beginning of the bypass (207 to 124 x 10(9).1(-1), when blood contacts with the synthetic surfaces of the circuits and the oxygenator, al though-the most marked reduction was found at the end of bypass (95.9 x 10(9).1-1), coinciding with protamine administration. The function and number of platelets tended to become normal in the first hours of the postoperative period.     

Ventricular assist device support in patients with mechanical heart valves

Background. Due to potential thromboembolic complications, mechanical valves within the native heart are often considered contraindications to ventricular assist device (VAD) support.

Methods. A retrospective review of VAD cases between June 1982 and March 1998 showed 8 patients with mechanical valves who were supported with Thoratec (Pleasanton, CA) VADs.

Results. There were 6 males and 2 females ranging in age from 20 to 69 years (mean 49.8 ± 5.6). Four patients were supported when they could not be weaned from cardiopulmonary bypass after reparative procedures and were thought to have reversible injuries. Four patients were supported as a bridge-to-cardiac transplantation. Two patients had mechanical mitral valves, 2 had aortic valve replacements, 1 had an aortic homograft and mechanical mitral valve, 2 had mechanical aortic and mitral prosthesis, and 1 patient had aortic, mitral, and triscupid valves. The types of valvular prostheses were St. Jude (5 patients) and Bjork-Shiley (3 patients). Duration of support ranged from 3.0 to 150 days (mean 34 days). Four patients were supported with biventricular assist devices and 4 had left VADs. Dextran and intravenous heparin anticoagulation were used in the shorter duration patients, with warfarin being used in the bridge patients. One patient received warfarin and aspirin. At the time of autopsy or device removal, only 1 of the 12 mechanical intracardiac valves showed any evidence of thrombosis, including the aortic valves in 2 patients supported for 2 and 5 months. There were no clinical thromboembolic events. Four patients (50%) were discharged (1 weaned, 3 transplanted).

Conclusions. The 50% (4 of 8) survival rate compares favorably with the 44% (41 of 92) overall survival rate for our Thoratec patients (bridge plus recovery) who did not have mechanical prosthetic valves. These data suggest that patients with mechanical intracardiac valves can be supported for short durations with some additional risk, which is yet to be determined.     

体外循环开心术后并发颅内出血

8例心脏病患者体外循环开心术后并发颅内出血或血肿，发生率为0．28％。其中硬膜下血肿4例，脑内血肿3例，蛛网膜下腔出血1例。6例死亡，2例存活，随访半年情况良好。对于体外循环心脏手术患者，应警惕颅内血肿发生并及时首选头部CT检查，正确把握开颅手术适应证。     

Antibacterial prophylaxis in heart surgery interventions with extracorporeal circulation]

Clinico-laboratory studies were conducted in 30 patients who underwent operations for heart diseases and thromboembolism of the pulmonary artery under extracorporeal circulation. Gentamicin and tobramycin were used for antibacterial prophylaxis. Study of the pharmacokinetics of the agents disclosed essential changes of the distribution volume and clearance of the antibiotics in the patients of the studied group, which made the routine regimen of their administration modified. Analysis of the results of administration of the agents according to a modulatory regimen showed its high prophylactic efficacy in the absence of side effects.     

Hepatitis syndrome following heart surgery using extracorporeal circulation

195 patients who underwent heart operations by means of extra-corporal circulation were followed-up for virus hepatitis in a prospective study. 15 cases of hepatitis occurred, 6 developed hepatitis type B, 9 hepatitis non-A-non-B. 41 out of 142 patients examined had no antibodies against cytomegaly virus, in 7 patients a seroconversion took place. Epstein-Barr-virus does not play a clinical role.