Circulation
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Dispatcher-delivered telephone instruction in cardiopulmonary resuscitation (CPR) has been proposed to increase rates of bystander CPR in cases of out-of-hospital cardiac arrest. We tested the efficacy of a previously developed CPR message using a recording mannikin in a high stress, simulated cardiac arrest scenario. Community volunteers were unaware they would perform CPR until immediately before each trial. ⋯ Because of the time required for telephone instruction, groups A and B started chest compressions a mean of 4.0 minutes after collapse compared with 1.2 minutes for group C (p less than 0.0001). We found that the previously untrained volunteers of group A performed CPR of an overall quality comparable to that performed by previously trained members of group C. Group A performed chest compressions significantly better than group C (p less than 0.02) but had greater problems performing effective ventilations.(ABSTRACT TRUNCATED AT 250 WORDS)
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Among 48 consecutive patients with pretransplant pulmonary vascular resistance (PVR) greater than 4 Wood units, 38 patients underwent orthotopic heart replacement (OHT), and the remaining 10 received a graft in a heterotopic position (HHT). The OHT recipients were smaller (63 vs. 73 kg, p less than 0.05) and received a larger donor heart (donor-recipient, 109% vs. 79%, p less than 0.001) with a shorter graft ischemic time (108 vs. 139 minutes, p less than 0.05) than HHT recipients, reflecting patient selection and surgical complexity. Comparison between the hospital survivors and nonsurvivors identified the selection of HHT and graft ischemic time in excess of 150 minutes as potent risk factors. ⋯ The higher the preoperative PVR value, the more substantial the reduction observed, resulting in normalization of PVR for all survivors. The incidence of early graft failure was similar between the groups, but HHT recipients frequently developed pulmonary complications and infection, resulting in a 30% hospital survival in contrast to 71% in OHT recipients (p less than 0.05). The results suggest that transplant candidates with pulmonary hypertension might better be treated by OHT with an oversized, on-site, viable donor heart than by HHT.
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A method is presented for maintaining aortic flow by mechanical means during intractable cardiac arrest. A spherical balloon was inserted into the left ventricle while the usual intra-aortic balloon was introduced into the thoracic aorta. Ventricular fibrillation was induced by direct current. ⋯ The intraventricular balloon capacity varied from 40 to 110 ml (six dogs weighing 16-24 kg) while the intra-aortic balloon capacity was 20 ml. An optimal pumping rate of 75 beats/min maintained an aortic flow of 0.9-1.5 ml/beat/kg and a mean pressure into the brachiocephalic trunk of 110 +/- 12.5 mm Hg (mean +/- SD). These experimental data indicate that an easily applied mechanical device system (needing no extracorporeal circulation) may be used to bridge the time between intractable cardiac arrest and implantation of an artificial heart or transplantation.
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We investigated the release of endothelium-derived relaxing factor (EDRF) in response to serotonin and histamine in the human internal mammary artery and saphenous vein. The arteries and veins were obtained intraoperatively and were suspended in organ chambers to record isometric tension. In mammary arteries, histamine (10(-8) to 3 X 10(-6) M) induced relaxations in rings with (70 +/- 5%, IC50, 6.5 +/- 0.2) but not without endothelium (p less than 0.005 for rings with compared with those without endothelium, n = 7-10). ⋯ The endothelium inhibited the maximal contraction to serotonin in arteries (p less than 0.034) but not in veins. Thus, EDRF protects against contractions induced by histamine and serotonin in the mammary artery but not in the saphenous vein. This may be important for improved graft function and patency of the artery compared with that of the vein.
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Multicenter Study Comparative Study Clinical Trial
Preoperative identification of patients likely to have left ventricular dysfunction after aortic valve replacement. Participants in the Veterans Administration Cooperative Study on Valvular Heart Disease.
The purpose of this study was to identify preoperative and intraoperative variables predictive of left ventricular dysfunction 6 months after aortic valve replacement. Patients were considered to have postoperative left ventricular dysfunction if the end-diastolic-volume index was greater than or equal to 101 ml/m2 or if the ejection fraction was less than or equal to 0.50. Data from 180 patients entered into the Veterans Administration Cooperative Study on Valvular Heart Disease who had technically satisfactory cardiac catheterizations 6 months postoperatively were analyzed by a series of univariate and multivariate analyses. ⋯ Although many patients with preoperative left ventricular dysfunction experience improved left ventricular performance after aortic valve replacement, performance does not always return to normal. For patients with either aortic stenosis or regurgitation, the strongest predictor of postoperative left ventricular dysfunction is preoperative dysfunction. These data support the concept that patients with moderate or severe aortic stenosis or regurgitation should be operated on before the onset of significant left ventricular dysfunction.