Detection of alkoxyl and carbon-centered free radicals in coronary sinus blood from patients undergoing elective cardioplegia.

Confirmation of the involvement of free radicals in postischemic injury in human heart has been elusive. The present study was performed to determine the presence of free radicals in coronary sinus blood from patients undergoing elective open heart surgery and cardioplegia. Six patients who were scheduled for nonurgent elective open heart surgery were used in this study. Coronary sinus blood samples were withdrawn at 1, 3, 5, 10, 15, 20, and 25 min in post-cross-clamp and immediately mixed with isosmotic alpha-phenyl-tert-butylnitrone (PBN) and then centrifuged to obtain plasma. Plasma samples were extracted with toluene and analyzed using electron spin resonance (ESR) spectroscopy. We observed ESR spectra consistent with the formation of alkoxyl and carbon-centered radical adducts of PBN (aN = 13.6 G, a beta H = 1.9 G, and aN = 14.1 G, a beta H = 4.2 G) in six of six patients. We obtained complete free radical production time courses during reperfusion from five patients, and all demonstrated a biphasic profile with an initial burst from 5 to 10 min followed by a second maxima at 25 min. Total PBN-adduct production during reperfusion increased in patients subjected to longer aortic cross-clamp times (global ischemia). These data demonstrate that postcardioplegia free radical production is detectable in coronary sinus blood using an ex vivo spin-trapping technique and that the extent of formation may be related to the severity of ischemia.

Relation of angina pectoris to coronary artery disease in aortic valve stenosis.

One hundred three patients with isolated, severe aortic stenosis (AS) were retrospectively analyzed to determine the relation of angina pectoris to angiographically significant coronary artery disease (CAD). All patients underwent coronary angiography regardless of the presence or absence of angina. Angina was significantly associated with CAD (p less than 0.002), with a sensitivity of 78% and a specificity of 53%. However, 25% of the patients without angina had angiographically significant CAD, and in these patients there was a 70% prevalence of 1-vessel disease. Patients with isolated, severe AS should undergo coronary angiography to identify coexistent CAD accurately. The absence of angina does not reliably exclude angiographically significant CAD.

Frequency of angiographically significant coronary arterial narrowing in mitral stenosis.

Ninety-six consecutive patients older than 40 years with severe mitral stenosis were retrospectively analyzed to determine the relation of angina pectoris (AP) and coexistent coronary artery disease (CAD). Of the 96 patients, 27 (28%) had angiographically significant CAD, 10 (37%) with AP and 17 (63%) without AP. Of the 96 patients, 21 had AP, 10 (48%) with angiographically significant CAD and 11 (52%) without (CAD). Of 75 patients without AP, 17 (23%) had angiographically significant CAD AP had a specificity of 84% and a sensitivity of 37% in its ability to detect significant CAD. The pulmonary artery systolic, diastolic and mean pressures and the pulmonary vascular resistance did not differ between patients with and those without AP (p greater than 0.05). It is concluded that coexistent CAD is commonly found in patients older than age 40 with severe MS, and is usually clinically silent.

Angina pectoris and coronary artery disease in isolated, severe aortic regurgitation.

Seventy-eight patients with isolated, severe aortic regurgitation (AR) were studied retrospectively to determine the prevalence of angiographically significant coronary artery disease (CAD) and its relation to angina pectoris (AP). Angiographically, significant CAD was present in 29 of 78 patients (37%), and 36 patients (46%) had AP. Twenty-one of 36 patients (58%) with AP and 8 of 42 patients (19%) without AP had angiographically significant CAD. AP as a predictor of significant CAD had a sensitivity of 73%, specificity of 69% and a risk ratio of 3:1. The predictive accuracy of detecting CAD in the absence of AP was 81%. The benefit from concomitant coronary artery bypass grafting at the time of aortic valve replacement for AR has not been clearly demonstrated; therefore, routine coronary angiography is still recommended for all AR patients older than 40 years undergoing aortic valve replacement.

In-hospital cardiopulmonary resuscitation during asystole. Therapeutic factors associated with 24-hour survival.

The most recent American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) during asystole include ventricular defibrillation, intubation, and the administration of epinephrine and atropine. This study reports results from a retrospective analysis of clinical, demographic, and treatment data collected during in-hospital CPR efforts in 123 patients in whom the initial rhythm was asystole. Twenty-eight (22.8 percent) of these patients were alive 24 h after CPR initiation. Patients who received norepinephrine drip (N = 43) were more likely to survive than those who did not (39.5 percent vs 14.1 percent; p less than .01), and those who received lidocaine drip were more likely to survive than those who did not (47.6 percent vs 18.2 percent; p less than .01). The best survival rate (57.1 percent) occurred among those who received both norepinephrine and lidocaine (N = 14). Survivors did not differ significantly from nonsurvivors in terms of age, gender, primary diagnosis, location of arrest, or duration of CPR efforts. The results suggest that aggressive resuscitation efforts which include the addition of norepinephrine and lidocaine drips to the AHA-recommended regimen of epinephrine and atropine may substantially increase the number of 24-h survivors. A pharmacologic mechanism involving norepinephrine-induced myocardial irritability and peripheral vasoconstriction, combined with lidocaine-induced suppression of abnormal automaticity, is offered as a possible explanation of the obtained results.

Zinc supplementation enhances the effectiveness of St. Thomas' Hospital No. 2 cardioplegic solution in an in vitro model of hypothermic cardiac arrest.

The present study was done to assess the effectiveness of a zinc-supplemented cardioplegic solution in an in vitro model of hypothermic arrest. Isolated hearts were perfused in the nonworking mode. All hearts were subjected to 2 hours of hypothermic arrest, at 10 degrees C, followed by 60 minutes of recovery. In protocol 1, arrest was initiated with infusion of cardioplegic solution with or without 30 mumol/l zinc for 5 minutes, which was then reinfused for 5 minutes every 15 minutes during arrest. In protocol 2, arrest was initiated with infusion of cardioplegic solution with or without 40 mumol/L zinc for 10 minutes. Cardioplegic solution (without zinc) was then reinfused for 5 minutes before the hearts were rewarmed. In protocol 1 hearts, peak postischemic left ventricular developed systolic pressure was 106 +/- 5 mm Hg and 80 +/- 3 mm Hg in zinc-treated versus control hearts, respectively (p < 0.05 by repeated-measures analysis of variance). In protocol 2 hearts, recovery of postischemic left ventricular developed systolic pressure peaked at 74 +/- 4 mm Hg and 46 +/- 8 mm Hg in zinc-treated and control hearts, respectively (p 0.05, repeated-measures analysis of variance). Similar effects were observed for the left ventricular rate of relaxation (p < 0.05, repeated-measures analysis of variance). Except for some minor effects, lactate dehydrogenase release was not affected by zinc supplementation. The present study demonstrates that zinc supplementation further enhances the normally observed preservation of postarrest cardiac function and suggests possible clinical utility for this metal as an additive to standard crystalloid cardioplegic solutions.

The effects of pressure and flow on hemolysis caused by Bio-Medicus centrifugal pumps and roller pumps. Guidelines for choosing a blood pump.

Two Bio-Medicus BP-50 centrifugal pumps and two roller pumps were tested simultaneously with porcine blood at 21 degrees +/- 1 degree C in four in vitro circuits to determine the effect of four combinations of flow and pressure conditions on blood damage. Flows of 300 ml/min (1/4-inch inner-diameter tubing in the roller pump) and 1775 ml/min (1/2-inch inner-diameter tubing in the roller pump) and pressure differences across the pump (delta P = outlet pressure--inlet pressure) of 215 mm Hg (n = 6) and 345 mm Hg (n = 5) were examined. The index of hemolysis (milligrams plasma hemoglobin per 100 L blood pumped) for the BP-50 pump was higher at a flow of 300 ml/min than at a flow of 1775 ml/min (p < 0.0002). At 300 ml/min, the index of hemolysis for the BP-50 pump tended to be higher at 345 mm Hg than at 215 mm Hg (mean +/- standard error of the mean, 135 +/- 22 versus 88 +/- 9, p = 0.059). At 1775 ml/min, there was no difference in the index of hemolysis for the BP-50 pump between 215 and 345 mm Hg (37 +/- 7 versus 29 +/- 5, p = 0.32). With the roller pump, the index of hemolysis was higher at a flow of 300 ml/min than at a flow of 1775 ml/min (p < 0.036), but there was no difference in the indexes of hemolysis between 215 and 345 mm Hg at 300 ml/min (60 +/- 9 versus 61 +/- 11, p = 0.93) or at 1775 ml/min (40 +/- 6 versus 36 +/- 6, p = 0.61). Comparison between the two types of pumps showed that the index of hemolysis was significantly higher for the BP-50 than for the roller pump at a flow of 300 ml/min and a delta P of 215 mm Hg (88 +/- 9 versus 60 +/- 9, p = 0.009), as well as at a flow of 300 ml/min and a delta P of 345 mm Hg (135 +/- 22 versus 61 +/- 11, p = 0.001). At a flow of 1775 ml/min, there was no difference in the index of hemolysis between the two pumps at either pressure condition.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective randomized comparison of Dacron and polytetrafluoroethylene aortic bifurcation grafts.

BACKGROUND: The purpose of this study was to compare the long-term results of Dacron and polytetrafluoroethylene (PTFE) aortic bifurcation grafts in a prospective randomized manner. METHODS: Sixty patients with aortoiliac occlusive disease were randomized to receive Dacron or PTFE bifurcation grafts. Preoperative risk factors, perioperative blood loss and fluid requirements, and postoperative complications were compared. A mean follow-up of 57 months was achieved. RESULTS: The immediate postoperative morbidity and mortality rates were similar in the two groups, and the long-term complications were low in number and comparable. The cumulative patency rate for Dacron graft limbs was 86% versus 95% for PTFE graft limbs. CONCLUSIONS: No significant differences were noted between the results achieved with Dacron and PTFE aortic bifurcation grafts.

Zinc-bis-histidinate preserves cardiac function in a porcine model of cardioplegic arrest.

BACKGROUND: We examined the ability of zinc-bis-histidinate to preserve postarrest myocardial function when added to a standard crystalloid cardioplegic solution. METHODS: Domestic pigs (35 to 50 kg) on left-sided cardiopulmonary bypass were subjected to 90 minutes of regional ischemia followed by 60 minutes of hypothermic cardioplegic arrest induced by antegrade infusion of 20 mL/kg cold St. Thomas' #2 cardioplegic solution with or without 100 mumol/L of zinc-bis-histidinate and maintained by infusion of 10 mL/kg of the same every 20 minutes. During reperfusion function was assessed at 1 and 3 hours over increasing preloads using the right-sided bypass method. RESULTS: At roller pump flows up to 2,000 mL/min, stroke work index-end-diastolic pressure curves were significantly (p < 0.05) higher and shifted to the left in treated hearts. In a series of pigs, echocardiography was used to determine end-diastolic and end-systolic volumes. At roller pump flows up to 3,500 mL/min, end-systolic pressure-end-systolic volume curves were significantly higher and shifted to the left in treated hearts. Left ventricular ejection fraction, fractional shortening, stroke volume, and cardiac output were significantly (p < 0.05) higher in treated hearts. Electron microscopy revealed that mitochondria in tissue not at risk appeared more swollen in control hearts. CONCLUSIONS: The results of this study support the conclusion that zinc-bis-histidinate is effective as a myocardial preservative when added to a crystalloid cardioplegic solution.

Aortic dissection: rupture into right ventricle and right pulmonary artery.

Rupture of an acute ascending aortic dissection into a surrounding cardiac chamber or pulmonary artery is an uncommon occurrence, and is often only diagnoses post mortem. Although fistulization (aortopulmonary and aorta-right atrial) after acute aortic dissection has been well documented in the literature, acute aortic dissection fistulizing into both the right ventricle and pulmonary artery has not. We report on a 75-year-old woman who presented with an acute ascending aortic dissection with both aortopulmonary and aorta-right ventricular fistulas who underwent repair and had long-term survival.

A methodological framework for the design of research on the evaluation of residents.

This paper describes a construct validation framework for research on the selection and evaluation of residents. The application of the proposed methodology to surgery residents is described. The need to measure non-cognitive and neuropsychological factors in addition to cognitive knowledge and technical ability is emphasized, and a research strategy that integrates theory formulation, internal validation, and external validation is presented. In this context, residents' competence is viewed as a multivariate construct that requires validation through longitudinal empirical studies and the use of multivariate statistical approaches.

In-hospital cardiopulmonary resuscitation: patient, arrest and resuscitation factors associated with survival.

Data on 470 adults with single in-hospital cardiac arrest resuscitations were analyzed to determine 24-h and discharge survival rates and to identify significant correlates of survival. One hundred fifty-three (33%) patients were alive 24 h after initiation of cardiopulmonary resuscitation; 69 (45% of 24-h survivors, 15% of all patients) were discharged alive. Logit analysis identified the following independently significant correlates of 24-h survival: arrest locations other than emergency room or cardiac care unit, CPR duration less than 15 min, non-cardiac primary diagnosis, non-asystolic dysrhythmia, less than one intravenous and one drip-administered inotrope and absence of pacemaker insertion and defibrillation. Fifty-one (94%) of 54 patients with all of these characteristics were alive 24 h after initiation of CPR. The same variables, as well as age less than 68 years and absence of intubation were statistically associated with discharge survival. Nine (64%) of 14 patients with all of these characteristics were discharged alive. Increased intervention was generally associated with increased mortality. Overall survival rates replicate previous reports and may reflect the effects of diagnosis-related groups policies on the average illness severity of the in-patient population, rather than failure of current CPR methods to improve the probability of survival. Use of the data as baseline for future studies and as a source of hypotheses for research on decision making are discussed.

Reduced length of stay following carotid endarterectomy under general anesthesia.

BACKGROUND: The widespread use of diagnosis-related groups has led to a significant reduction in the length of hospital stay following many surgical procedures. In light of this, an examination of early discharge following carotid endarterectomy under general anesthesia was undertaken. PATIENTS AND METHODS: A prospective study of 72 patients was conducted, in which the workup was done on an outpatient basis, admission took place on the same day as surgery, and patients were discharged home on the day after carotid endarterectomy. RESULTS: There were no strokes or deaths following carotid endarterectomy, and only two transient ischemic attacks occurred. In 88% of the cases, discharge was possible on the first postoperative day. CONCLUSIONS: Early discharge following carotid endarterectomy under general anesthesia is safe and cost effective.

Clinical and echocardiographic features of isolated severe pure mitral regurgitation.

Recent studies have shown that rheumatic heart disease is no longer the main cause of isolated severe pure mitral regurgitation. In this study, we evaluated various clinical and echocardiographic features found in the syndrome of mitral regurgitation. Our data is consistent with recent reports that mitral valve prolapse and coronary artery disease are now the predominant causes of mitral regurgitation and that rheumatic heart disease is a much less common etiology. In addition, our data suggest that clinical evaluation alone is usually very accurate in identifying the correct etiology. Various clinical and echocardiographic features found in the subsets of acute and chronic mitral regurgitation are described. Specifically, patients with acute mitral regurgitation were more likely to have echocardiographic evidence of segmental left ventricular dysfunction and flail mitral valve leaflet. In chronic mitral regurgitation, atrial fibrillation and left atrial dilatation were more commonly present. Echocardiography was found to be more useful in the detection of the complications of coronary artery disease rather than in identifying its presence. Patients with a New York Heart Association classification of IV and those with echocardiographic evidence of an increased left ventricular endsystolic dimension or left ventricular hypertrophy had a worse prognosis.

A dynamic method for setting roller pumps nonocclusively reduces hemolysis and predicts retrograde flow.

In general, roller pumps are set almost occlusively despite evidence that nonocclusive settings cause less hemolysis. Almost-occlusive settings are used because of the concern that forward flow would not be accurately known if retrograde flow were allowed to occur through a nonocclusive gap. This article presents a dynamic method for setting roller pumps nonocclusively that overcomes the many difficulties of the "drop method" for setting occlusion. Studies were conducted to determine the effect of nonocclusive settings on pump flow and hemolysis generated; the results suggest that roller pumps can and should be set more nonocclusively than is the currently accepted standard to reduce pump related hemolysis without greatly affecting pump performance. The dynamic method allows retrograde flow to be easily predicted and corrected with an increase in pump speed.

Bloodless testing for microporous membrane oxygenator failure: a preliminary study.

The use of a bloodless solution and high pressure to accelerate microporous membrane oxygenator (MMO) failure was investigated. It was hypothesized that albumin acts as a wetting agent, contributing to plasma leakage through the membrane, and that high MMO outlet pressure accelerates the process. Three MMO, B-Bentley BCM-40 (n = 7), M-Medtronic Maxima (n = 4), and S-Sarns 16310 (n = 7) were tested at 37 +/- 2 degrees C using three identical closed recirculating circuits and four conditions: 1) Lactated Ringer solution (LR) with MMO outlet pressure (Pmo) 750 mmHg; 2) LR + albumin (4 g/100 ml), Pmo 150 mmHg; 3) LR + albumin, Pmo 300 mmHg; and 4) LR + albumin, Pmo 750 mmHg. "Blood" flow and gas flow were maintained at 2 l/min. Failure was indicated when Na+ was detected in the effluent of the MMO exhaust gas. There were no failures without albumin in the solution. B and M showed no signs of failure under any of the test conditions at 78 hours. S failed at (mean +/- SEM) 4.9 +/- 1.0, 12.1 +/- 0.2, and 19 hours for conditions 4, 3, and 2 respectively. Preceding failure, inlet gas pressure increased more than eightfold (27 +/- 1 to 224 +/- 34 mmH2O). These preliminary results are similar to previous findings with blood and suggest that high MMO outlet pressure and the presence of albumin may promote plasma breakthrough for S. The combination may provide a basis for an accelerated bloodless test for MMO compatibility with long-term respiratory support.

Reliability and accuracy of resident evaluations of surgical faculty.

This study examines the reliability and accuracy of ratings by general surgery residents of surgical faculty. Twenty-three of 33 residents anonymously and voluntarily evaluated 62 surgeons in June, 1988; 24 of 28 residents evaluated 64 surgeons in June, 1989. Each resident rated each surgeon on a 5-point scale for each of 10 areas of performance: technical ability, basic science knowledge, clinical knowledge, judgment, peer relations, patient relations, reliability, industry, personal appearance, and reaction to pressure. Reliability analyses evaluated internal consistency and interrater correlation. Accuracy analyses evaluated halo error, leniency/severity, central tendency, and range restriction. Ratings had high internal consistency (coefficient alpha = 0.97). Interrater correlations were moderately high (average Pearson correlation = 0.63 among raters). Ratings were generally accurate, with halo error most prevalent and some evidence of leniency. Ratings by chief residents had the least halo. Results were generally replicable across the two academic years. We conclude that anonymous ratings of surgical faculty by groups of residents can provide a reliable and accurate evaluation method, ratings by chief residents are most accurate, and halo error may pose the greatest threat to accuracy, pointing to the need for greater definition of evaluation items and scale points.

Physician partnering: a provider network primer.

The face of health care is changing daily due to pressures brought about by dissatisfied consumers, physicians, and employers. The authors of this article believe that the only way to bring about a better health care system is for physicians to take back the administration of the medical profession from the insurers. Physicians must take the financial risks necessary to innovate a medical system that will benefit themselves, their patients, and their patients' employers. This article presents the basic business concepts needed to establish physician provider networks (PPNs) as well as the benefits and pitfalls of the various types of associations into which a PPN can enter. Clearly, the future will belong to those physicians who have the foresight to invest their talents and their finances in the business aspects of managed care.

Provider service organizations: a method to establish physician prerogatives.

The face of health care is changing daily because of pressures brought about by dissatisfied consumers, physicians, and employers. We believe that physicians need to take back from insurers the administration of the medical profession. Physicians must assume the financial risks necessary to create a medical system that will benefit themselves, their patients, and their patient's employers. This article presents the basic business concepts needed to establish Provider Service Organizations (PSOs) as well as the benefits and pitfalls of the various types of associations into which a PSO can enter. Clearly, the future belongs to those physicians who have the foresight to invest their talents and their finances in the business aspects of managed care.