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Biomedical subjects

H T Bahnson

Publications and source records attributed to H T Bahnson.

At least 55 records · Page 3Linked to original sources
PubMed1984

Targeted blood levels of cyclosporin for cardiac transplantation.

Forty-nine patients have undergone cardiac transplantation since July, 1982, and have been treated with maintenance cyclosporin and low-dose prednisone, 15 to 20 mg. Cyclosporin dose has been targeted to a whole-blood level of 1,000 ng/ml as measured by radioimmune assay. The actuarial survival rate in this group of patients has been 79% at 12 months and 71% at 21 months. Histologic rejection has occurred at all blood levels of cyclosporin, as has significant nephrotoxicity. The hepatic toxicity encountered has been more a clinical nuisance than significant problem. The administered dose of cyclosporin required to reach a target of 1,000 ng/ml has varied between 2 and 30 mg/kg/day. The average perioperative and late serum creatinine levels were 1.2 and 1.49 mg/dl and occurred with cyclosporin levels of 1,078 and 1,068 ng/ml, respectively. Late cyclosporin toxicity has persisted despite reduction in the dose of cyclosporin below the targeted 1,000 ng/ml. Some method of blood level monitoring is necessary in patients receiving cyclosporin immune suppression to assure adequacy of the administered dose. The 1,000 ng/ml target has provided adequate immune suppression. Significant nephrotoxicity has not correlated with the blood level measured.

Bilirubin↗
PubMed1983

Histocompatibility in cardiac transplantation with particular reference to immunopathology of positive serologic crossmatch.

Cardiac allografting was carried out in 33 patients during the past 2 years. Twenty-one (64%) of the patients are alive and others lived for different periods after transplantation. The number of HLA-AB and HLA-DR antigens matched or mismatched was not significantly different between the surviving and deceased patients. However, 100% (4 of the 4) of the patients with a positive serum crossmatch with donor T lymphocytes are deceased as compared to the 25% (7 of the 28) mortality rate for crossmatch-negative patients. All four of the deceased patients with a positive crossmatch had demonstrable deposition of immunoglobulins in the capillaries of the donor heart at autopsy, whereas no immunoglobulin or fibrinogen deposition was seen in the hearts of crossmatch-negative patients. Three of the four patients with positive crossmatches had sera cytotoxic to lymphocytes of more than 25% of the persons, of a 42 member panel, whereas in the remaining one the serum was cytotoxic to less than 5% of the panel members. In crossmatch-negative patients, the sera were cytotoxic to less than 20% of the panel members with one exception. The relevance of cytotoxic antibodies to lymphocytes of panel members, crossmatch, and tissue deposition of immunoglobulins is discussed.

Adult↗
PubMed1983

Challenges.

Explore the source record for details and available documents.

Cost Control↗
PubMed1982

Coarctation of the aorta in infants and children: 25 years of experience.

Repair of coarctation of the aorta was performed in 334 patients ranging from less than a year to 16 years of age at Children's Hospital of Pittsburgh from 1953 to 1977. Resection and end-to-end anastomosis were performed in 310, interposition grafts in 7, and other procedures in 17. There were 41 operative deaths among the 95 infants less than 1 year old (43% mortality); all of these infants had associated cardiac anomalies. Only 1 operative death occurred in patients older than a year (0.4% mortality). No hospital deaths occurred in patients with isolated coarctation of the aorta. Eleven late deaths were due to associated anomalies (7) and unrelated or unknown causes (4). Postoperatively, hemorrhage occurred in 7, paradoxical or persistent hypertension in 128, postcoarctectomy syndrome in 32, neurological problems in 14, pulmonary complications in 53, and infections in 12 patients. Restenosis occurred in 26 patients (8%); only 10 have required reoperation. Residual hypertension was present in 28 of 264 patients (11%). Mortality from coarctation resection remains high in infants, but is minimal in children older than 1 year. Based on minimizing the risk of restenosis and residual hypertension, elective repair of coarctation is recommended when the patient is about 6 years of age.

Adolescent↗
PubMed1982

Carotid endarterectomy under regional (conductive) anesthesia.

Carotid endarterectomy is reliable in the prevention of strokes due to arteriosclerotic disease at the carotid bifurcation. This is a retrospective review of 314 carotid endarterectomies performed at the University Health Center of Pittsburgh. The objectives of the study were to determine if regional anesthesia was a safe technique for carotid endarterectomy and to determine whether the neurologic complications that occurred were embolic or ischemic in origin. In patients who were neurologically intact before operation, the perioperative mortality was 0.88% and the incidence of neurologic complications was 3.1%. This is comparable to the current literature. Observations of the awake patient suggested that half the neurologic deficits that occurred in this series were due to embolization rather than to cerebral ischemia. Further more, the incidence of non-neurologic complications under general anesthesia was 12.9%. Under regional anesthesia, the incidence of non-neurologic complications was 2.8%. The data supports carotid endarterectomy under regional block as safe and reliable method.

Anesthesia, Conduction↗
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↗
PubMed1982

Effect of induced erythrocythemia on hypoxia tolerance during physical exercise.

The effect of induced erythrocythemia on hypoxia tolerance during physical exercise was determined for five male mountain climbers. Treadmill testing was performed under four conditions: 1) prereinfusion, normoxia (Pre-N); 2) prereinfusion, hypoxia (Pre-H); 3) postreinfusion, normoxia (Post-N); and 4) postreinfusion, hypoxia (Post-H). An altitude of 3,566.2 m was simulated by having subjects breath a gas mixture of 13.5% O2-86.5% N2 at normal barometric pressure. Tests were administered immediately before and 24 h after autologous transfusion of 750 ml of red blood cells. Hematocrit increased from 43.3% at prereinfusion to 54.8% at postreinfusion. Hemoglobin concentration increased from 13.80 g X 100 ml-1 at prereinfusion to 17.63 g X 100 ml-1 at postreinfusion. Maximal O2 uptake (VO2 max, 1 X min-1) increased (P less than 0.05) by 12.8% (3.28 to 3.70) from Pre-N to Post-N and 13.0% (2.62 to 2.96) from Pre-H to Post-H. Treadmill performance time (s) increased (P less than 0.05) by 15.8% (793 to 918) from Pre-N to Post-N and 8.9% (687 to 748) from Pre-H to Post-H. VO2 max decreased by 20.1% from Pre-N to Pre-H and by 9.8% from Pre-N to Post-H. Treadmill time decreased by 13.4% from Pre-N to Pre-H and 5.7% from Pre-N to Post-H. The calculated change in hypoxia tolerance following reinfusion indicated that physiological altitude was improved by 463.6 m. It was concluded that induced erythrocythemia increased hypoxia tolerance during physical exercise.

Adult↗
PubMed1982

Pulmonary valvulotomy alone for pulmonary stenosis: results in children with and without muscular infundibular hypertrophy.

Pulmonary valvulotomy for valvular pulmonic stenosis has been performed in 78 children at the Children's Hospital of Pittsburgh. Although 27 patients had muscular hypertrophy of the infundibulum, a muscle resection was employed in only one child. Examinations 2 to 18 years after operation have not demonstrated electrocardiographic (ECG) or clinical evidence of persistent right ventricular hypertension, indicating resolution of the muscular outflow tract narrowing. Systolic right ventricular pressure averaged 30 mm Hg in 10 patients at postoperative catheterization: Six of these patients had peak right ventricular pressures greater than 100 mm Hg immediately after valvulotomy. The diameter of the infundibulum in systole was compared to valve ring diameter and expressed as a ratio (I/V). This correlated with the preoperative and intraoperative right ventricular pressures, but did not identify patients who might fail to resolve secondary muscular hypertrophy. A murmur of pulmonary regurgitation was present in 70% of the patients after operation, but was without clinical significance. In the absence of fixed infundibular obstruction or excessive right ventricular hypertension above 200 mm Hg, resection of infundibular hypertrophy is not recommended.

Adolescent↗
PubMed1982

The third manpower study of thoracic surgery: 1980 report of the Ad Hoc Committee on Manpower of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons.

An ad hoc committee was appointed by The Society of Thoracic Surgeons (STS) in 1977 in order to determine the available manpower and workload of thoracic surgeons in 1976. This committee conducted a survey of the professional activities and geographic location of all known surgeons certified by the American Board of Thoracic Surgery (ABTS) at that time. A summary of this study indicated the available and projected thoracic surgery manpower. The report also determined the present and projected health care needs of the population of the United States through 1993. Because thoracic surgery needs to continue to meet the health care needs of the United States in an appropriate yet economical fashion, the STS and The American Association for Thoracic Surgery (AATS) undertook a joint review to determine again the available manpower and its workload in calendar year 1980. In addition, this study compared its findings with the 1976 report in order to detect changes in the workload and need for thoracic surgical services. A questionnaire was mailed to 3,584 certified thoracic surgeons. There were 2,675 responses. The material was sent to the Academic Computer Services at George Washington University Medical Center for tabulation and data processing. This report summarizes the results of this survey. It also compares these data with those obtained in the 1976 study and, based on this information, attempts to project the thoracic surgery manpower needs in the next decade by using several hypothetical models.

Forecasting↗
PubMed1981

Expanded polytetrafluoroethylene femoropopliteal grafts: forty-eight-month follow-up.

Ninety-eight expanded polytetrafluoroethylene (PTFE) grafts were used for femoropopliteal reconstruction in 81 patients. Forty-eight-month follow-up is now available for 20 grafts and 36-month follow-up is available for 51 grafts. Seventy-four percent of the patients were men. Thirty-one percent had diabetes mellitus, 38% had hypertension, 36% had atherosclerotic heart disease, 18% had prior myocardial infarction, 17% had a previous operation for aortoiliac disease, and 14% had a previous ipsilateral femoropopliteal bypass procedure. The indication for operation was claudication in 47%, rest pain in 20%, and ischemic pregangrene or gangrene in 32% of patients. Distal runoff was angiographically graded as good (76%) or poor (24%). Seventy-three grafts were anastomosed to the proximal or midpopliteal artery (above the knee); 25 grafts were anastomosed to the distal popliteal artery (below the knee). Graft occlusion was determined by the return of ischemic symptoms, disappearance of previously palpable pulses, or by angiographic or Doppler assessment. There were no operative deaths. Nonocclusive causes of graft loss were death (7), amputation (2), infection (2), and aneurysm (5). The overall cumulative patency rate calculated by the life-table method, according to the criterion of occlusion alone, was 75% at 6 months, 68% at 2 years, 58% at 3 years, and 48% at 4 years. Preoperative symptoms, the number of patent outflow vessels, popliteal anastomosis placed above or below the knee, or hypertension did not adversely affect graft patency. Diabetes mellitus was associated with significantly increased graft failure. The PTFE graft is an acceptable alternative for femoropopliteal reconstruction for the patient without a suitable autologous saphenous vein.

Aged↗
PubMed1980

Absent right superior vena cava with persistent left superior vena cava: implications and management.

Seven cases of absent right superior vena cava with persistent left superior vena cava and normal situs were diagnosed at Children's Hospital of Pittsburgh. All patients had associated cardiac defects. In two cases the diagnosis was made at autopsy, the first in 1957 and in a 26 day old infant with multiple cogenital defects and the second in 1965 in a 22 day old infant who had pulmonary atresia with ventricular septal defect and patent ductus arteriosus. Since 1966 absent right superior vena cava has been diagnosed at cardiac catheterization in five children. Three of these children have had surgery, two for subaortic stenosis and one for an atrial septal defect. One has an insignificant atrial septal defect and the fifth has a ventricular septal defect. The electrocardiogram of four reveals s short P-R interval and a leftward frontal plane axis of the P wave, suggesting a low atrial focus. None has had any significant conduction problem. All five children are living and well, the oldest has survived 13 years postoperatively. Certain precautions are necessary should corrective cardiac surgery or transvenous pacemaker insertion be necessary.

Adolescent↗
PubMed1980

Cardiopulmonary dynamics during arteriovenous perfusion: cardiac output, pulmonary arterial resistance, and right venticular stroke work.

The effects of arteriovenous perfusion on myocardial performance, pulmonary circulatory dynamics, and organ preservation were studied in dogs in order to evaluate the applicability of arteriovenous extracorporeal membrane oxygenation for partial respiratory support. Studies were made on normally oxygenated dogs, on dogs made hypoxic by oxygen deprivation and ventilatory depression, and on dogs with pulmonary injury and moderate pulmonary hypertension induced by injection of oleic acid into the right ventricle. The latter two groups were included to assess the changes that occur in cardiopulmonary dynamics in the presence of hypoxia and pulmonary hypertension. A microchannel membrane oxygenator was employed to provide partial respiratory support to the group of animals with pulmonary injury. The results indicate that no deleterious hemodynamic changes occurred in any of the groups of animals with arteriovenous flow for periods of up to 5 hours at rates corresponding to 20 to 35% of the total cardiac output. Adequate systemic oxygenation was provided by the microchannel oxygenator at these rates of arteriovenous perfusion.

Animals↗
PubMed1979

Anomalous origin of the right coronary artery from the pulmonary artery.

Three patients with anomalous origin of the right coronary artery from the pulmonary artery are presented together with a review of the 14 patients with this anomaly previously reported. One of the current patients is the youngest to be diagnosed before operation and the youngest to undergo corrective operation. Although the lesion is usually asymptomatic, it may contribute to sudden death. The only suggestive physical finding is a continuous murmur with diastolic accentuation, which is present only in some patients. There are no diagnostic electrocardiographic or chest roentgenographic changes. Diagnosis is made best by selective left coronary arteriography showing retrograde filling of the right coronary artery from collateral vessels. Operative repair should consist either of direct reimplantation of the proximal right coronary artery into the aortic root or of saphenous vein bypass graft to the coronary artery with ligation of its origin. Operation is recommended when the lesion is recognized.

Aged↗