Biomedical subjects
Publications and source records attributed to K D Murray.
A case of histoplasmosis seen as left recurrent laryngeal nerve paralysis in a 49-year-old man is described. The patient had roentgenographic findings of a solitary, noncalcified left upper lobe mass and mediastinal adenopathy. Tissue diagnosis of histoplasmosis was obtained using a thoracotomy, allowing institution of appropriate treatment.
Blunt chest trauma resulting in combined aortic disruption and cardiac rupture, although a common autopsy finding, was found reported only once previously in a surviving patient. We report two cases repaired through a left posterolateral thoracotomy in which the cardiac injury was unsuspected and presented as an intraoperative finding of hemopericardium. With improved emergency resuscitation in the field and faster transport of these cases to tertiary care centers, this combination of lesions may be seen more frequently. Suggestions for their diagnosis and management are presented.
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Peripheral venous bullet embolization to the heart is a rare event. We report our experience with one patient who suffered peripheral venous bullet embolization to the right ventricle and review the 38 patients with this phenomenon previously reported in the literature. The clinical presentation of patients with peripheral venous bullet embolization to the right ventricle is discussed. In addition, the indications for surgery and the therapeutic approaches available to patients with bullet embolization are discussed.
Artificial heart research is carried out in the United States, Europe, Japan, Argentina and the Soviet Union, and prolonged survival has been achieved in animals, which has increased the interest of the media and public in this field. Although recent advances are promising, device malfunction remains an obstacle to overcome in most laboratories. Relying on noninvasive monitoring techniques we were able to diagnose and correct artificial heart malfunction safely using surgical techniques employed during the heart implantation.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Metastasis of colorectal cancer to the lung is a frequent occurrence. Resection of pulmonary metastasis provides the only effective treatment. The initial detection of disease is usually with a chest radiograph. A CAT scan determines the number of lesions, resectability and other metastatic disease. Candidates for surgical excision are those patients with completely resectable singular, multiple, and bilateral metastasis, and those with metachronous liver lesions excised for cure. Exposure of unilateral disease is via a thoracotomy and of bilateral disease via a sternotomy. Metastatic lesions are removed by wedge resection with conservation of lung tissue. Postoperative recovery is usually rapid with low morbidity and mortality. Long-term success for these resections remains controversial.
The J-7 total artificial heart (TAH) can restore normal vascular hemodynamics in humans treated for end-stage heart failure, but less is known regarding its effect on hormones elevated under these conditions. A 49-year-old man with NYHA Class IV end-stage heart failure received a J-7-70 TAH as a bridge to transplantation. Pre-TAH cardiac index was less than 2 L/min/m2 with end organ dysfunction, increased venous and pulmonary pressures, and a low arterial pressure. The TAH provided an immediate cardiac index greater than 3 L/min/m2 with normal hemodynamics and organ function. Pre-TAH renin, aldosterone, and atrial natriuretic factor (ANF) levels were markedly elevated: 147 ng/dl, 29.4 ng/dl, and 380 pg/ml, respectively. All values declined dramatically by the fifth postoperative day, with the aldosterone and ANF values returning to normal at 11.5 ng/dl and 37 pg/ml, respectively. Renin levels reached normal values by the fourth postoperative week. Once normal values were obtained, they remained in this range for the 57 days of TAH function. The TAH, used in end-stage heart failure, restores normal hemodynamics and compensatory hormonal levels. These hormones can be used as indicators of proper TAH function in such patients.
Drugs given to a total artificial heart (TAH) calf isolate their vascular effects independent of the myocardium. During experiments, the TAH maintains full ejection, constant heart rate, and percent systole, and uses no vacuum. Cardiac output (CO) varies solely and directly with preload. Six calves received an infusion of isoproterenol, a beta agonist, and three calves received propranolol, a beta antagonist. The isoproterenol was resumed after beta blockade. Isoproterenol alone caused a significant increase in CO, an effect that was attenuated but not eliminated with beta blockade. Both isoproterenol and propranolol decreased AoP, but only isoproterenol increased preload. Beta receptors play a significant role in decreasing venous capacitance with increased preload and CO, independent of the myocardium.
Jarvik-5 and Jarvik-7 total artificial hearts (TAHs) and Utah-100 TAHs were fabricated and implanted in calves and sheep. In the Jarvik series, 30.7% had mechanical failures (16.1% catastrophic). In the Utah-100 TAH series, 11.1% had mechanical failures (3.7% catastrophic). Failures were classified as: 1) diaphragm failures; 2) valve-holding ring failures; 3) air-leak failures; and 4) prosthetic valve failures. Marked reduction in mechanical failure for the Utah-100 TAH is attributed to progressive component redesign, material selection, and more stringent quality control criteria.
Pneumatic artificial hearts are powered by compressed air that is delivered through percutaneous tubes. A stress relief device, termed a skin button, surrounds these tubes as they exit from the recipient's tissues. The skin button is designed to protect the tissues from damage and provide a secure material-tissue interface. Prevention of superficial and invasive infection is the primary goal of the skin button. Eight calves were studied prospectively to identify gross or microscopic infection with the skin button. All animals who survived more than sixty days (62-136) had both gross and microscopic evidence of infection. All animals surviving less than 60 days (13-43) had no gross evidence of infection but one had subcutaneous microscopic abscess formation. No animal died secondary to a skin button infection. Skin buttons cannot prevent infection but they can contain the pathologic process in the superficial tissues with no evidence of systemic effects.
The artificial heart (AH) is devoid of physiologic connections to the recipient's native feedback control loops. Control of an AH can be either passive or dynamic. Passive intrinsic control provides limited AH response to physiologic demands. Dynamic control requires the sensing of metabolic and hemodynamic signals and their incorporation into self-adjusting AH function. A single metabolic or hemodynamic parameter cannot provide sufficient data accurately to adjust AH pumping in response to varying blood flow demands. A combination of input control signals is required for reliable and flexible AH function. The selection of appropriate input control parameters and their incorporation into AH controller designs remains a critical step in the achievement of a permanent, totally implantable AH.
The native atria remains intact after total artificial heart (TAH) implantation. The electrical activity of the recipient's atria can be recorded from wires placed during TAH implantation. Regulating TAH heart rate by coupling it with native atrial activity has the potential for a more physiologically responsive TAH. The reactivity of the atrial impulse rate is a critical component of this link, but little is known about atrial responsiveness after TAH placement. Two human and three animal TAH recipients had recordable atrial electrical activity. Human atrial impulse rate after TAH was relatively constant at rest but unresponsive to physiologic stimuli. Analysis of human atrial contraction provided no discernable effect on ventricular filling. Animal atrial impulse rate at rest was more rapid than calves without a TAH. The bovine TAH recipients had an atrial impulse rate that responded to catecholamine stimulation and blockade. Isoproterenol caused a significant rise in atrial impulse rate (152 +/- 16 impulses per minute to 216 +/- 24 impulses per minute; p < 0.05) and propranolol caused a decrease in atrial impulse rate (142 +/- 20 impulses per minute to 122 +/- 19 impulses per minute; p > 0.05). Despite beta blockade, the atrial impulse rate remained abnormally elevated secondary to unknown factors. Animal atrial contraction did appear to intermittently augment TAH ventricular filling. These data indicate that the atria remains electrically intact after TAH implantation. The human atrial impulse rate was unresponsive to physiologic stimuli although the animal atrial impulse rate was affected by exogenous catecholamine administration, but the rate remained abnormally rapid.(ABSTRACT TRUNCATED AT 250 WORDS)
Myocardial high-energy phosphate content has been used as a parameter to evaluate the adequacy of donor organ preservation. The purpose of this study was to assess current techniques of preservation by measuring high-energy phosphates in cold preserved (4 degrees C) human donor hearts. Endomyocardial biopsy samples of the donor heart right ventricular septum (n = 24) were compared with samples from patients with normal cardiac function evaluated before chemotherapy (n = 12). Left ventricular and right ventricular ejection fractions were measured by means of radionuclide angiography early (24 to 72 hours) and late (mean 42 days) postoperatively. Mean total cold ischemic time was 146 +/- 54 minutes (range, 89 to 340 minutes). ATP nmol/mg noncollagenous protein in donor hearts was 38.2 +/- 10.7 and 31.9 +/- 13.6 (p = NS) in normal hearts. Early postoperative left ventricular and right ventricular ejection fraction was 55% +/- 14% and 40% +/- 9%, respectively. Late postoperative left ventricular and right ventricular ejection fraction was 64% +/- 14% and 50% +/- 10%, respectively; both represent significant increases in right and left ventricular ejection fraction (p less than 0.05). No correlation was found between ischemic time and donor ATP, ischemic time and ejection fraction, or ejection fraction and ATP. Three patients with normal donor heart ATP content had severe, but reversible, early graft dysfunction. In summary, currently used human donor heart preservation techniques are associated with normal values of high-energy phosphates and usually excellent early and late postoperative graft function.(ABSTRACT TRUNCATED AT 250 WORDS)