The Annals of thoracic surgery
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Using transesophageal echocardiography during open heart operations, we found another form of retained intracardiac air, "pooled air," in addition to the form of "bubbles" that had been reported by other authors. The pooled air was detected in all of 13 patients (100%); it was located at the right upper pulmonary vein in 13 (100%), left ventricular apex in 9 (69.2%), left atrium in 8 (61.5%), right coronary sinus of Valsalva in 8 (61.5%), left atrial appendage in 4 (30.8%), and left upper pulmonary vein in 3 (23.1%). ⋯ Because intracardiac air rapidly changes its locations and appearances, continuous monitoring is important, especially at weaning from bypass. The long-axis view of the heart is useful not only for detecting and locating the air, but also for guiding and evaluating the procedures to remove air.
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Lidocaine addition to crystalloid cardioplegic solution for prevention of reperfusion ventricular fibrillation after the release of the aortic cross-clamp was studied in 50 patients undergoing coronary artery bypass grafting and in 30 patients undergoing mitral or aortic valve replacement. Twenty-six of the patients undergoing coronary artery bypass grafting received lidocaine, 100 mg/L of cardioplegia, whereas a control group of 24 patients received cardioplegia without lidocaine. ⋯ In the valve group, lidocaine cardioplegia also reduced significantly the incidence of reperfusion ventricular fibrillation from 93% to 42%. In both groups, lidocaine cardioplegia decreased the number of direct-current countershocks required to defibrillate the heart, with no significant increase in the incidence of high-grade atrioventricular block.
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Comparative Study
Renal dysfunction and intravascular coagulation with aprotinin and hypothermic circulatory arrest.
High-dose aprotinin was used in 20 patients undergoing primary or repeat operations on the thoracic or thoracoabdominal aorta using cardiopulmonary bypass and hypothermic circulatory arrest. The activated clotting times immediately before the establishment of hypothermic circulatory arrest exceeded 700 seconds in all but 1 patient. Three patients (15%) required reoperation for bleeding. ⋯ None of these 20 patients required reoperation for bleeding. Although aprotinin has been shown to reduce blood loss in patients having cardiac operations employing cardiopulmonary bypass, this benefit was not attained in this group of patients with thoracic aortic disease in whom hypothermic circulatory arrest was used. Use of aprotinin in elderly patients undergoing these procedures was associated with an increased risk of renal dysfunction and failure, and of myocardial infarction and death.
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The optimal temperature for cerebral protection during hypothermic circulatory arrest is not known. This study was undertaken to test the hypothesis that deeper levels of cerebral hypothermia (< 10 degrees C) confer better protection against neurologic injury during prolonged hypothermic circulatory arrest ("colder is better"). Twelve male dogs (20 to 25 kg) were placed on closed-chest cardiopulmonary bypass via femoral artery and femoral/external jugular vein. ⋯ Histologic injury scores were assigned to each animal (range, 0 [normal] to 100 [severe injury]). At the end of the observation period, profoundly hypothermic animals had better neurologic function (neurodeficit score, 5.7% +/- 4.0%) compared with deeply hypothermic animals (neurodeficit score, 41% +/- 9.3%; p < 0.006). Every animal had histologic evidence of neurologic injury, but profoundly hypothermic animals had significantly less injury (histologic injury score, 19.2 +/- 1.2 versus 48.3 +/- 1.5; p < 0.0001).
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Between 1990 and 1992, 346 consecutive patients underwent coronary artery bypass procedures. Ninety-eight patients (group A) from 1990 served as historical controls, and 248 patients (group B) from 1991 to 1992 served as a prospective, consecutive cohort for statistical comparison. The two groups varied in the type of myocardial protection used: intermittent cold crystalloid cardioplegia was used in group A and continuous warm blood cardioplegia in group B. (Two patients in group A received intermittent cold blood cardioplegia, and these 2 patients are grouped with the crystalloid group for the sake of convenience. ⋯ Group B patients were less likely to have development of complex postoperative arrhythmias. Ventricular fibrillation at unclamping was noticeably rare (2.0% in group B versus 84% in group A; p < 0.05). The average group B heart resumed sinus rhythm 72 seconds after declamping.(ABSTRACT TRUNCATED AT 250 WORDS)