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Biomedical subjects

G M Deeb

Publications and source records attributed to G M Deeb.

At least 91 records · Page 5Linked to original sources
PubMed1989

Sternal osteomyelitis: treatment with rectus abdominis muscle.

Sternal osteomyelitis complicates recovery in a small number of patients following median sternotomy. Techniques for operative treatment have in common the wide debridement of devitalised tissue and administration of culture-specific antibiotics. The resultant wound can be managed by delayed primary closure or transposition of well-vascularised adjacent tissue. Omentum, pectoralis major muscle and rectus abdominis muscle are suitable for transposition either alone or in combination. Our series is composed of ten patients who underwent rectus abdominis muscle transfer for the treatment of sternal osteomyelitis. The rectus abdominis obliterates dead space in the lower third of the wound, a difficult area to reach with the pectoralis major muscle. Five patients had one rectus abdominis muscle alone transposed, avoiding the aesthetic and functional deficits of pectoralis major transposition and the risks of omental transfer. Wound healing occurred in every case with a minimum of postoperative complications.

Abdominal Muscles↗
PubMed1989

Comparison of polyclonal antibody sera for early prophylaxis following cardiac transplantation.

In order to test different polyclonal antibody regimes as early prophylaxis against cardiac rejection, 42 patients (ages 30 to 60 years) transplanted at the University of Michigan from December 1986 to August 1988 were randomized to receive antithymocyte globulin (ATGAM, Upjohn, n = 19) or antilymphoblast globulin (MALG, University of Minnesota, n = 23). Cyclosporine (CYA), steroids, and azathioprine (AZA) administration was similar in all randomized patients during early prophylaxis. CYA was begun preoperatively and maintained at a serum level of 250-300 ng/ml. After an initial steroid taper, patients were maintained on 0.3 mg/kg/day. AZA was begun after polyclonal prophylaxis at 1-2 mg/kg. All patients received either ATGAM or MALG for 7 days or until the serum CYA reached 250 ng/ml. Although sex, pretransplant hemodynamics, follow-up length, total drug dose, mortality (one per group), postoperative white blood cell and lymphocyte counts did not differ between groups, MALG significantly delayed the first rejection episode as compared to ATGAM (35 +/- 4 vs 22 +/- 3 days, P less than 0.05). Additionally, there was decreased rejection during follow-up for the MALG group with 1.5 +/- 0.2 rejections per patient as compared to 2.3 +/- 0.3 with ATGAM. Furthermore, the significant infection rate with MALG was only half that of the ATGAM group (6/23 vs 11/19) (P less than 0.05). The beneficial effect of MALG may be due to immune-specific differences in its polyclonal spectrum.

Adult↗
PubMed1989

The role of amrinone in potential heart transplant patients with pulmonary hypertension.

Orthotopic heart transplantation is contraindicated in patients with pulmonary hypertension and an elevated pulmonary vascular resistance. In an attempt to make otherwise unacceptable patients possible candidates for heart transplantation, amrinone was administered intravenously to 27 individuals with a transpulmonary gradient and pulmonary vascular resistance in the abnormal range. Twenty-four of 27 patients (89%) responded positively. Twenty-one of 27 (78%) went on to transplantation and 20 of 21 (95%) survived the procedure. A second study compared amrinone therapy with conventional therapy in 38 potential transplant candidates with pulmonary hypertension. Amrinone was more effective in reducing pulmonary hypertension than conventional therapy with high-dose diuretics, digitalis, and captopril (86% v 63%). Survival rate of those awaiting transplantation was also significantly higher in the amrinone group (91% v 63%). Although the protocol for comparing the two regimens does not allow for extrapolation of the results (amrinone was administered in-hospital under close monitoring, whereas conventional therapy was self-administered at home), the findings confirm the clinical impression that amrinone seems more effective and safer than conventional therapy in the treatment of potential heart transplant patients with pulmonary hypertension.

Amrinone↗
PubMed1989

Hypothermia or continuous ventilation decreases ischemia-reperfusion injury in an ex vivo rat lung model.

The susceptibility of lung tissue to ischemia-reperfusion injury has made distant procurement of heart-lung allografts difficult. The effects of hypothermia, ventilation without perfusion, and various reperfusion solutions (PSS/Ficoll or whole blood) on the development of ischemia-reperfusion lung injury were investigated. Use of an ex vivo rat lung model in which the above variables were individually varied permitted a direct approach for these studies. Normothermic ischemia for 1 hour caused significant damage, documented by increased iodine 125 bovine serum albumin (125I-BSA) in alveolar lavage fluid and lung parenchyma compared with nonischemic controls. Hypothermic (4 degrees C) ischemia for 4 hours in lungs reperfused with salt solution and for as many as 12 hours in lungs reperfused with whole blood caused no significant increase in 125I-BSA in alveolar lavage fluid and lung parenchyma compared with nonischemic controls. Lungs ventilated without perfusion showed no increase in 125I-BSA leakage compared with controls. The ex vivo rat lung model is excellent for studying ischemia-reperfusion injury. It is reproducible, allows for variance of reperfusion solutions, and permits change in temperature and ventilation easily.

Animals↗
PubMed1988

Xanthine oxidase inhibition attenuates ischemic-reperfusion lung injury.

Ischemic-reperfusion lung injury is a factor potentially limiting the usefulness of distant organ procurement for heart-lung transplantation. Toxic oxygen metabolites are considered a major etiologic factor in reperfusion injury. Although oxygen-free radicals may be generated by many mechanisms, we investigated the role of xanthine oxidase in this injury process by using lodoxamide, a xanthine oxidase inhibitor, to inhibit ischemic-reperfusion injury in an isolated rat lung model. Isolated rat lungs were perfused with physiologic salt solution (PSS) osmotically stabilized with Ficoll until circulating blood elements were nondetectable in the pulmonary venous effluent. Lungs were rendered ischemic by interrupting ventilation and perfusion for 2 hr at 37 degrees C. After the ischemic interval, the lungs were reperfused with whole blood and lung injury was determined by measuring the accumulation of 125I-bovine serum albumin in lung parenchyma and alveolar lavage fluid as well as by gravimetric measurements. Lung effluent was collected immediately pre- and postischemia for analysis of uric acid by high-pressure liquid chromatography. Lodoxamide (1 mM) caused significant attenuation of postischemic lung injury. Uric acid levels in the lung effluent confirmed inhibition of xanthine oxidase. Protection from injury was not complete, however, implying that additional mechanisms may contribute to ischemic-reperfusion injury in the lung.

Animals↗
PubMed1988

Aggressive treatment of chylothorax complicating transhiatal esophagectomy without thoracotomy.

Chylothorax is an unusual complication after transhiatal esophagectomy (THE) and in the past 10 years has occurred in 11 of 320 patients (3%) undergoing this operation for diseases of the intrathoracic esophagus. Four patients had benign esophageal disease: scleroderma reflux esophagitis (1), caustic stricture (1), and achalasia (2), and each had undergone at least one previous esophageal operation. Seven patients had intrathoracic esophageal carcinoma--two upper-third, two middle-third, and three distal-third lesions. Excessive chest tube drainage more than 72 hours after THE was the standard presentation, and the diagnosis of chylothorax was confirmed by the administration of cream through the jejunostomy feeding tube placed routinely at operation. The character of the chest tube drainage changed from serous to opalescent. Aggressive treatment of this complication was the rule, and every patient underwent a thoracotomy between 2 to 14 days (average, 6 days) after the diagnosis was established. Cream was administered through the jejunostomy tube before operation, and in each case the thoracic duct injury was readily identified and controlled with suture ligatures. There were no deaths in this group, and there was one recurrence of the fistula that required reoperation; all patients were discharged from the hospital within 3 to 29 days (average, 10 days) after thoracic duct ligation. It is concluded that early recognition of a chylothorax after transhiatal esophagectomy with prompt transthoracic ligation of the injured duct results in a shorter overall hospitalization and lower morbidity and mortality from this complication. The traditional conservative management of chylothorax with intravenous hyperalimentation and no or low-residue enteral feedings has little place in this nutritionally depleted patient population.

Adult↗
PubMed1986

Complement activation during cardiopulmonary bypass. Comparison of bubble and membrane oxygenators.

A prospective randomized trial involving 91 patients undergoing cardiopulmonary bypass compared the effects of bubble oxygenators (with and without methylprednisolone sodium succinate) and membrane oxygenators on complement activation and transpulmonary sequestration of leukocytes. Patients were divided as follows: Group I, 30 patients, bubble oxygenator; Group II, 31 patients, bubble oxygenator and methylprednisolone sodium succinate (30 mg/kg); Group III, 30 patients, membrane oxygenator. In Group I, C3a increased from 323 +/- 171 ng/ml during cardiopulmonary bypass to 1,564 +/- 785 ng/ml at 25 minutes after bypass (p less than 0.0001). A significant decrease in C3a was found in Groups II and III compared to Group I (p less than 0.0001). C5a did not change significantly during cardiopulmonary bypass in any group. Reestablishment of pulmonary circulation at the end of bypass produced significant transpulmonary leukocyte sequestration in Group I; the median cell difference was 1,700/microliter. Transpulmonary sequestration was significantly (p less than 0.0001) less in Group II (median cell difference = 200/microliter) and in Group III (median cell difference = 400/microliter) than in Group I. We conclude that cardiopulmonary bypass with a bubble oxygenator alone initiates significantly (p less than 0.0001) more C3a activation and leukocyte sequestration than when methylprednisolone sodium succinate (30 mg/kg) is given 20 minutes before the start of cardiopulmonary bypass with a bubble oxygenator or when a silicone membrane oxygenator is used.

Adrenal Cortex Hormones↗
PubMed1985

Artificial heart and left ventricular assist devices.

We believe there will be a place in cardiac surgery for a variety of assist and replacement devices. The extracorporeal assist devices, with or without extracorporeal membrane oxygenation, will be needed for acute situations requiring time for diagnosis and prognosis to be determined. There will also be a place for intrathoracic paraventricular assist devices that may temporarily or permanently support the right or left ventricle. Finally, we believe that there will be a number of patients whose native cardiac function is of no help at all and whose hearts probably should be removed to make room for an improved blood pump of human design. Pneumatic ventricles are presently available and we should see increasing use of them over the next couple of years. The convenience for a patient of electrical wires instead of pneumatic hoses coming out of the chest is obvious. However, the complexity and cost of the overall system is considerably greater, further testing and development is needed. Dr. William Pierce already has kept an animal alive for over 6 months with an electrically driven heart. Clearly, the electrically driven systems are the pumps for the next decade.

Assisted Circulation↗
PubMed1984

The artificial heart in human subjects.

In preparation for clinical implantation of the Utah J-7 pneumatic artificial heart as a permanent cardiac substitute, the device was implanted into five brain-dead human subjects. This report presents our results and details our two most successful trials. Three different surgical implant techniques were utilized in the five subjects. Because of the unique "no risk" situation of the subjects, the function of the artificial heart could be tested in a manner not advisable in patients, but necessary for clinical preparation. The implantable total artificial heart was able to maintain physiological hemodynamics in two subjects for 41 and 72 hours at which time the trials were electively terminated.

Blood Pressure↗
PubMed1983

The effects of cardiovascular drugs on the defibrillation threshold and the pathological effects on the heart using an automatic implantable defibrillator.

Internal defibrillating leads were implanted in 6 dogs through a left thoracotomy and in 6 pigs through a subxiphoid approach. The effects of digoxin (0.04 mg per kilogram of body weight), procainamide (15 mg per kilogram), and propranolol (0.2 mg per kilogram) on the defibrillation threshold was determined 30 to 60 minutes following intravenous administration. Resultant blood levels were equal to or greater than therapeutic levels. Individually these drugs resulted in no appreciable change in the defibrillation threshold from baseline. Pathological study of the myocardium obtained from 6 dogs that underwent more than two hundred shocks each did not demonstrate any abnormality. The 6 pigs were reliably defibrillated, this indicating that thoracotomy is not required for successful implantation. The automatic implantable defibrillator is not the definitive treatment for recurrent ventricular arrhythmias, but is a practical regimen of therapy for a select group of high-risk, out-of-hospital patients. These observations advance our knowledge of the use of this device and give more assurance for future implantation in this select group of patients.

Animals↗
PubMed1982

Cardiac transplantation with cyclosporin A and prednisone.

Influenced by continuing improvement in results from Stanford, cardiac transplantation was resumed at the University Health Center of Pittsburgh in June 1980. Cyclosporin A (CyA) became available to the authors early in 1981. This report describes the preliminary experience with 21 patients who were treated between March 1981 and April 10, 1982 with cyclosporin A and low-dose steroids. Age ranged from eight to 53 years, median 46 years. Median age of ten patients disabled because of idiopathic myocardiopathy was 33 years; it was 45 years in the 11 suffering from ischemic heart disease. Sixteen of the 21 patients survived. Eleven have survived for three months, if which six have survived for six months, giving a cumulative survival of 74 and 66%, respectively. Four died perioperatively; one died at six weeks and one at four months. Hyperacute rejection resulted in one death at 12 hours even though the warm and cold lymphocytotoxic crossmatch for T and B cells was negative as evaluated by trypan blue. The two late deaths were related to infection. No late death has occurred because of rejection, and a unique feature is that three recipients with a lymphocytotoxic mismatch did not develop hyperacute rejection. The number of infectious episodes and nonviral infections appears to be less than that associated with the use of azathiaprine and larger doses of steroids. Cyclosporin A (5-10 mg/kg/d) and low-dose prednisone (rapidly tapered in seven days from 200 mg to 15-20 mg/d) is effective in preventing early morbid rejection of the transplanted heart.

Adolescent↗
PubMed1981

Lead systems for internal ventricular fibrillation.

We examined the feasibility of using a standby automatic implantable defibrillator and established thresholds for internal defibrillation. The implantable defibrillator senses ventricular fibrillation and delivers an electrical impulse for defibrillation. Two lead systems for the device have been investigated. System I consists of two 12-cm2 silicone-covered titanium mesh patches attached to the atrial and diaphragmatic pericardial surfaces. System II has an identical diaphragmatic patch and a titanium spring catheter, with a 12-cm2 surface area of conductivity, placed transvenously in the right atrium. Both systems were implanted by thoracotomy in 12 dogs (mean weight 20 kg) and by a subxiphoid approach in 10 pigs (mean weight 20 kg). The defibrillation threshold (lowest energy required for 80% success) was determined periodically for 54 weeks in the dogs (615 trials) and at 6 weeks for the pigs (100 trials). In dogs, the mean defibrillation threshold with system I leads at 4 weeks was 10.5 J and did not change significantly over a 54-week period (p greater than 0.05). Similar results were obtained in the pig at 4 weeks. The defibrillation thresholds for both lead systems in dogs and pigs using a transpleural thoracotomy or a subxiphoid approach are satisfactory for an implantable defibrillator that produces 20-35 J.

Animals↗
PubMed1980

Clinical experience with pediatric microporous oxygenator for profound hypothermia.

The Travenol TMO Total Bypass Membrane Oxygenator-Pediatric satisfactorily transfers oxygen and carbon dioxide under standardized conditions of operation during total high-flow bypass at normothermia or moderate hypothermia. This oxygenator has not been used at rates of flow less than 1 L/min or at temperatures below 23 degrees C. The current technique requires a venous and arterial pump with 5% recirculation to assure that pressure in the blood phase does not exceed the pressure above which blood may seep through the adhesive seals into the gas envelope. Conventional methods of perfusion were modified for use at profound hypothermia (18 degrees C) with low-flow bypass or circulatory arrest. Clinical experience with 22 children, preceded by six laboratory experiments, indicates that satisfactory control of arterial gases can be achieved and maintained.

Cardiopulmonary Bypass↗
PubMed1980

Thromboresistant surface coatings for the measurement of cardiac output through continuous low flow peripheral A-V shunts.

The dilution technique for determining cardiac output using indocyanine green dye is limited in patients weighing less than 20 kg because of the obligatory volume loss. Reproducible achieved using the green dye dilution method by the establishment of a low flow peripheral arteriovenous shunt. The shunt materials were treated with thromboresistant agents--TDMAC (7%) and albumin (1 g/dl)--to facilitate the use of this technique without heparin. For A-V shunt flow rates of 8-30 cc/min reproducible values of cardiac output were obtained for up to 38 hours which were in good agreement with determinations made using the conventional technique of dye dilution.

Animals↗
PubMedDate not supplied

Resolution of large azygos vein aneurysm following stent-graft shunt placement in a patient with Ehlers-Danlos syndrome type IV.

Ehlers-Danlos syndrome (EDS) type IV is a rare connective tissue disorder associated with thin-walled, friable arteries and veins predisposing patients to aneurysm formation, dissection, fistula formation, and vessel rupture. Azygos vein aneurysm is an extremely rare condition which has not been reported in association with EDS in the literature. We present a patient with EDS type IV and interrupted inferior vena cava (IVC) with azygos continuation who developed an azygos vein aneurysm. In order to decrease flow through the azygos vein and reduce the risk of aneurysm rupture, a stent-graft shunt was created from the right hepatic vein to the azygos vein via a transhepatic, retroperitoneal route. At 6 month follow-up the shunt was open and the azygos vein aneurysm had resolved.

Adult↗
PubMedDate not supplied

The dissected aorta: percutaneous treatment of ischemic complications--principles and results.

PURPOSE: Describe the principles and results of percutaneous treatment of ischemic complications of aortic dissection. MATERIALS AND METHODS: Twenty-four patients with aortic dissection complicated by ischemic compromise of the liver or bowel (n = 15), kidney (n = 18), or lower extremity (n = 13) were evaluated by means of aortography, intravascular ultrasound, and manometry, and were treated percutaneously. Visceral arteries were classified as obstructed or nonobstructed. Obstruction was classified as static, in which the dissecting hematoma extended into and narrowed the lumen of a branch artery, or dynamic, in which the dissection flap prolapsed into the vessel origin or narrowed the true lumen (TL) above it. Treatment consisted of vascular stents alone (n = 4), or balloon fenestration (n = 20) without (n = 8) or with (n = 12) vascular stents. RESULTS: Obstruction was present in 77 arteries and was static in 12 arteries, dynamic in 45 arteries, static and dynamic in 17 arteries, and indeterminate in three arteries. Percutaneous treatment did not alter false lumen (FL) pressure, but reduced the peak systolic interluminal pressure gradient from 28 mm Hg to 2 mm Hg and restored flow in 71 of 77 arteries (92%). Six patients died within 30 days (25% operative mortality), none as a result of the procedure. Two additional patients died in follow-up from complications of an expanding FL. Technical complications in two patients due to altered hemodynamics after initial intervention were recognized and corrected percutaneously during the same procedure. CONCLUSIONS: Percutaneous fenestration and endovascular stent deployment are indicated to restore blood flow to arteries compromised by aortic dissection. The prognosis of patients is related to the ischemic injury sustained prior to the percutaneous interventional procedure and, in patients with acute type I dissection who have not undergone surgery, to the preoperative stability of the FL.

Adult↗