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Biomedical subjects

D M Behrendt

Publications and source records attributed to D M Behrendt.

14 recordsLinked to original sources
PubMed1979

Effects of methylprednisolone in cardioplegic solution during coronary bypass grafting.

The effects of adding 500 mg. of methylprednisolone to each liter of cardioplegic solution were studied in patients undergoing coronary artery bypass grafts. Patients were randomly assigned to control (12 patients) or steroid-treated groups (10 patients). The cardioplegic solution was identical in the two groups except for the added methylprednisolone. Contractile element velocity (VCE and left ventricular end-diastolic pressure (LVEDP) were recorded immediately before and after perfusion in the operating room. There were no differences between the two groups with respect to these two variables or the postoperative courses. Thus this study fails to demonstrate a beneficial effect of methylprednisolone when added to cardioplegic solutions.

Coronary Artery Bypass↗
PubMed1978

Effects of cardioplegic solution on human contractile element velocity.

A technique for measuring the maximum contractile element velocity (Vpm) of the myocardium was developed, verified, and employed in patients to allow accurate intraoperative assessment of the adequacy of myocardial protection. Four groups of patients were studied. Ten patients had coronary artery bypass grafts (CABG) with cardioplegia; 13 had CABG with coronary perfusion, ventricular fibrillation at 28 degrees C, and aortic clamping for distal anastamoses; 6 had aortic valve replacement (AVR) with cardioplegia; and 7 had AVR with coronary perfusion to the beating heart. For cardioplegia, a solution of 5% dextrose in 0.2% saline at 4 degrees C with 25 mEq of potassium chloride and 12.5 gm of mannitol was infused initially, followed by 500 ml every 30 minutes. Clinically all patients did well, and there were no deaths. Patients having CABG with intermittent coronary perfusion during ventricular fibrillation had significant (p less than 0.01) depression of Vpm from 38.3 to 30.8 sec-1 while Vpm in patients having CABG with cardioplegia was unchanged. Patients having AVR with continuous coronary perfusion or with cardioplegia (average anoxia time, 70.4 minutes) had no significant change in Vpm. We conclude that this cardioplegic solution provided adequate protection of myocardial function for up to 105 minutes of continuous aortic clamping in humans. The depression in Vpm observed following CABG with intermittent coronary perfusion is consistent with previous suggestions that this combination is detrimental because of maldistribution of coronary blood flow during ventricular fibrillation.

Aortic Valve↗
PubMed1978

Myocardial revascularization in patients receiving long-term propranolol therapy.

Twenty-seven patients receiving long-term propranolol therapy underwent myocardial revascularization to relieve stable or unstable angina. The patients were randomly divided into two groups, one (Group 1) in which propranolol was discontinued 48 hours prior to operation and one (Group 2) in which patients received a final dose of propranolol 1 to 2 hours prior to operation. Several physiological variables were compared, and there was no statistically significant difference between the groups except for a slower pulse rate in Group 2 patients. Although the patients in Group 1 showed a greater frequency of hypertension before bypass, the incidence of postoperative complications and perioperative myocardial infarction was the same for both groups. The findings of this study indicate that myocardial revascularization is safe even if propranolol is administered up to 1 or 2 hours before operation.

Adult↗
PubMed1978

Management of unusual traumatic ruptures of the aorta.

Blunt injuries to the ascending aorta and branches of the aortic arch are unusual but must be considered in any victim of a high speed decelerating injury. Because there are no characteristic clinical or roentgenographic findings, aortography is the only definitive method of establishing the diagnosis. Aortography should therefore, be performed upon any patient who has had a high speed decelerating injury, regardless of the clinical or the roentgenographic findings. An early operation will prevent exsanguination.

Adolescent↗
PubMed1978

Effect of temperature of cardioplegic solution.

This study tests the hypothesis that the efficacy of cardioplegic solution depends upon its chemical constituents rather than on its temperature alone. A standard preparation of right heart bypass in the dog was utilized. Left ventricular function curves were inscribed before and after 1 hour of aortic cross-clamping. No deterioration in function was observed in nonischemic control hearts or in hearts protected with cardioplegic solution consisting of potassium chloride (25 mEq. per liter) and mannitol (12.5 Gm. per liter in 5 percent dextrose and 0.2 percent saline at either 4 degrees C or 28 degrees C. Severe myocardial depression was observed in hearts rendered ischemic for 1 hour at 28 degrees C. without protection and also in hearts perfused with 5 percent dextrose and 0.2 percent saline at 28 degrees C. without the potassium chloride and mannitol. The evidence from this study indicates that cardioplegic solution exerts a protective effect beyond that which is afforded by hypothermia.

Animals↗
PubMed1976

The treatment of acute traumatic rupture of the aorta: a 10-year experience.

Forty-three patients with aortic rupture secondardy to blunt trauma have been treated at the University of Micigan within the past 10 years with an overall salvage rate of 70%. The diagnosis should be suspected in anyone who has sustained a high speed decelerating injury, if the chest roentgenogram shows media-stinal widening, whether or not there is hypertension of the upper extremities; systolic murmur, or external evidence of chest injury. Aortography should be employed to confirm the diagnosis and to determine the site or sites of rupture. Repair of the lesion should be undertaken as soon as possible and takes priority in most instances over associated injuries. Repair in almost all cases can be accomplished safely and quickly using a bypass shunt without the aid of extracorporeal circulation.

Accidents, Traffic↗
PubMed1975

Evaluation of myocardial function.

In assessing myocardial contractility one may examine isolated heart muscle, the isolated whole heart in controlled circumstances, or the heart in an intact patient. In each situation a number of different indices of contractility may be recorded, each of which has merit but none of which is perfect. Some reflect events occurring during isometric contraction prior to ejection, such as rate of change in intraventricular pressure, maximum velocity of muscle shortening, and velocity of shortening of contractile elements. Others reflect ejection phenomena such as stroke volume, the Starling curve, and the ejection fraction. None of these indices is entirely independent of preload, afterload, and heart rate, and these factors must be controlled. In the whole heart, especially in a clinical setting, this may be difficult. Many clinical studies of myocardial function fail to recognize the need for controlling these variables and therefore are of limited validity.

Cardiomyopathy, Hypertrophic↗
PubMed1975

Complications of pulmonary resection.

The following complications of pulmonary resection are discussed with reference to their frequency of occurrence, etiology, diagnosis, and treatment: pulmonary insufficiency, arrhythmias, residual intrapleural air spaces, prolonged air leaks, postpneumonectomy empyema, bronchopleural fistula, cardiac herniation, lobar gangrene, esophagopleural fistula, pulmonary embolism, and tumor embolism.

Arrhythmias, Cardiac↗
PubMed1975

The Blalock-Hanlon procedure. A new look at an old operation.

The Blalock-Hanlon procedure has been carried out in 48 neonates with 10 early deaths (21%). This compares favorably with the reported early mortality for balloon atrial septostomy. Most striking have been the length of palliation, freedom from complications, and low incidence of late death among these patients. In contrast, reported series of balloon septostomies have shown a high incidence of strokes, repeat hospitalization, inadequate palliation, and late deaths. Since palliation is reliable following a Blalock-Hanlon procedure, we do not favor early correction with hypothermic arrest but recommend it at 12 to 18 months of age, when conventional perfusion can be easily utilized.

Heart Atria↗