Biomedical subjects
Publications and source records attributed to R M Sade.
Autotransfusion is an accepted adjunct to the treatment of massive bleeding associated with intra-abdominal trauma. We describe a case of massive air embolism during autotransfusion for a gunshot wound to the vena cava. Treatment required thoracotomy and direct aspiration of air. The patient recovered without sequelae.
The ideal priming fluid for cardiopulmonary bypass is not known. We designed a study to determine whether there are important differences in the clinical effects of hydroxyethyl starch versus albumin when used in priming fluid, and in the clinical effects of colloid versus crystalloid priming fluid. We prospectively randomized 83 adult patients undergoing coronary artery bypass or valve replacement. All patients were managed by standardized protocol, and they received one of three priming fluids for bypass: hydroxyethyl starch (HES), 26 patients; albumin (ALB), 28 patients, and lactated Ringer's solution (LRS), 29 patients. The groups were stratified by body weight and type of operation. We measured 41 variables relating to operative time factors, fluid balance, bleeding, and organ function (renal, cardiac, and pulmonary) at several time intervals. The LRS group had a significantly lower colloid osmotic pressure than the other two groups, and the HES group had a substantially higher blood viscosity. Although the prothrombin time was significantly lower in the LRS group (p less than 0.05), the differences were very small and not clinically important. The platelet count in the HES group was significantly lower than in the other two groups immediately after bypass, but it was not different by the time the patients left the operating room. There were no differences among the groups in chest tube drainage, blood bank usage, or fluid balance. Postoperatively, the pulmonary shunt fraction was significantly greater in the LRS group. Body weight increased more in the LRS than in the HES and ALB groups (p = 0.01). No adverse reaction to the prime solutions was noted. The differences between the HES and ALB groups--prothrombin time, platelet count, and blood viscosity--had no apparent clinical effects; thus, the two may be considered clinically equivalent. The greater somatic and pulmonary fluid accumulation in the LRS group suggests that colloid is preferable to crystalloid in priming fluid.
A 40 000 M.W. glycoprotein was isolated from human thymus. This molecule binds lentil lectin, reacts with an antiserum made against the p25 antigen (the human Thy 1 homologue) and possesses almost identical amino acid composition as the p25 antigen and its 40 000 M.W. dimer.
We hypothesize that it may be possible to treat complete heart block by transplanting right atrial myocytes directly into the ventricular wall where they may set the rate of ventricular contraction at their own intrinsic rate. The biologic background for this conjecture has already been determined to a large extent. However, a few critical unanswered biologic questions must be addressed before the development of this suggested new therapy becomes a mere technologic exercise.
From 1971-1981, 18 patients with discrete subaortic stenosis were treated surgically at the Medical University of South Carolina. Echocardiography was diagnostic in 10 of 11 patients in whom it was used. Preoperative cardiac catheterization was performed in all patients. The preoperative left ventricular outflow systolic pressure gradient was 82.0 +/- 27.2 mmHg (mean +/- SD) (range 30-145). In 16 (88.8%) patients excision of the subaortic membrane was complete, and relief of left ventricular outflow obstruction was good. The excision was incomplete in 2 patients; one required reoperation for residual gradient and developed complete heart block, and the other had a residual gradient of 60 mmHg and was in New York Heart Association functional class II when lost to follow-up. These data suggest that complete excision of the discrete subaortic stenosis is important to achieve good relief of left ventricular outflow obstruction.
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We have shown that patch aortoplasty relieves the aortic pressure gradient substantially better than resection with end-to-end anastomosis in infants with coarctation of the aorta. Growth of the intact posterior wall of the unresected coarctation after aortoplasty, however, has not yet been demonstrated to occur. We studied 21 infants less than 2 years of age who underwent prosthetic patch repair of coarctation after 1975. Associated lesions were present in 16 patients, and 12 had a concomitant procedure. Two patients died in the hospital, and 4 died later, all of causes unrelated to the coarctation repair. Systolic blood pressure in the right arm declined from 140 +/- 41 mm Hg (mean +/- standard deviation) preoperatively to 101 +/- 19 mm Hg postoperatively in the whole group and to 95 +/- 12 in 10 patients followed for more than 3 years. The right arm-left leg systolic pressure gradient declined from 66 +/- 22 mm Hg to 5 +/- 14 in all patients and to 4 +/- 13 in the group followed more than 3 years. Hypoplastic transverse arch was seen in all but 2 patients. Its relative diameter increased in 6 of 9 patients who underwent catheterization postoperatively and increased more than 50% in 3 patients. Two patients have evidence of narrowing of the aorta at the patch, but both have normal blood pressure in the right arm. In the patient with longest follow-up, an 8-month-old infant seen 8 years after operation, angiograms show the diameter of the aorta at the coarctation to be greater than that at the transverse arch and at the descending aorta.(ABSTRACT TRUNCATED AT 250 WORDS)
Excellent clinical results have been achieved by both resection with end to end anastomosis and synthetic patch aortoplasty for the repair of coarctation of the aorta in older children. Increasing experience with exercise stress testing in the postoperative evaluation of patients with coarctation has allowed the discovery of less obvious differences between the two procedures. To evaluate these differences further, the stress tests of 50 postoperative patients who underwent coarctation repair were reviewed: 26 patients with end to end anastomosis and 24 with synthetic patch aortoplasty. Twenty normal control subjects were similarly exercised. Systolic blood pressure in the arm and leg was evaluated before and after the test. Heart rate, electrocardiogram and arm blood pressure were monitored during the test. The mean arm systolic blood pressure was higher at all points of measurement in the patients who underwent repair by end to end anastomosis than in the group who underwent patch aortoplasty. These systolic pressure differences reached statistical significance only for standing arm blood pressure before exercise (p less than 0.05) and for supine arm systolic blood pressure immediately after exercise (p less than 0.01). There was no difference in arm-leg pressure gradient between the two study groups before exercise; however, after exercise the group with end to end anastomosis had significantly higher arm-leg pressure gradients (p less than 0.001). Significant differences between the two types of repair not apparent at rest were found immediately after exercise. The long-term prognostic importance of an exercise-induced arm-leg blood pressure gradient remains to be determined. However, exercise stress testing is sensitive in demonstrating these differences.
From April 1, 1979 to August 31, 1983, 228 patients underwent isolated aortic (AVR) (118) or mitral (MVR) (90) valve replacements with a new tilting disc valve prosthesis, the St. Jude prosthesis, at the Medical University of South Carolina. Age ranged from 6 to 84 years (mean 49.1 +/- 19.2 AVR, 44.5 +/- 16.5 MVR). Male sex predominated in the AVR group (68%) and female sex in the MVR group (68%). Thirty-five patients (16.8%) had associated coronary bypass surgery (AVR 23.7%, MVR 7.8%). There were seven deaths (3.4%) occurring during the same hospitalization (AVR: 3/118, 2.5%; MVR: 4/90, 4.4%). Follow-up is 97.6% complete and ranges from 1 to 54 months (mean 19.6 +/- 12.4). In the AVR group, nine late deaths have occurred and actuarial survival at 42 months is 86.7 +/- 3.8%. Three patients have sustained thromboembolic episodes for a linearized rate of 1.6% patient-year, and the probability of remaining free of thromboembolism at 42 months is 96.9 +/- 1.8%. The mean improvement in functional class from preoperative to postoperative is 3.1 +/- 0.7 to 1.2 +/- 0.4 (p less than 0.001). In the MVR group, there have been four late deaths, and the actuarial survival at 42 months is 89.3 +/- 3.8%. Two patients have sustained thromboembolic complications for a linearized rate of 1.2%/patient-year, and the probability of remaining free of thromboembolism at 42 months is 97.2 +/- 2%. The mean improvement in functional class from before to after surgery is 3.2 +/- 0.7 to 1.3 +/- 0.5 (p less than 0.001). There have been no thromboses of the St. Jude valve in the mitral or aortic position, no mechanical failures, and no patient has had significant valve-related hemolysis. Because of this experience, the St. Jude Medical heart valve prosthesis is our prosthesis of choice for any patient undergoing valve replacement with a mechanical prosthesis.
From January 1972 to April 1982, 125 adults underwent operation for congenital heart disease at the Medical University of South Carolina. Age ranged from 18 to 73 years, with an average age of 31 years. A variety of defects were seen. Atrial septal defect (59 patients), ventricular septal defect (15 patients), patent ductus arteriosus (14 patients), tetralogy of Fallot (14 patients), and coarctation of the aorta (9 patients) were the most common. There were 48 men and 77 women in the study. Most patients presented with recent onset of dyspnea on exertion or at rest, but 16 patients were asymptomatic. Eight patients died after surgery for an overall operative mortality rate of 6 per cent. The most common postoperative complication was arrhythmia (13 patients, 10%). Despite recent advances in the diagnosis and treatment of congenital heart disease in infants, a significant number of patients apparently escape detection and first present with congenital heart disease as adults. Prompt diagnosis and surgical intervention will usually produce excellent results and relief of symptoms in these patients.
Over a 10-year period (1972-1981) 40 valves were replaced in 35 patients with native valve endocarditis. Hospital mortality was 17 per cent (6/35). Long-term follow-up is current in 27 of 29 survivors. Twenty-three of these patients are alive with a mean follow-up of 44.7 months (11-91 months) and an overall survival of 70 per cent. Eighty-seven per cent of the long-term survivors are New York Heart Association (NYHA) Class I or II. In our series, anular or myocardial abscess was an ominous finding; only 25 per cent (2/8) of these patients were alive at long-term follow-up. When abscess was not present, early operation (less than 4 weeks of preoperative antibiotic therapy) was associated with better long-term survival (91%) than was late operation (greater than 4 weeks of preoperative antibiotic therapy, 79%).
Three infants with coarctation of the thoracic aorta, patent ductus arteriosus (PDA), and ventricular septal defect (VSD) underwent repair of the coarctation in three different institutions. Despite a technically uncomplicated operation, each was noted to have significant paraplegia postoperatively. Retrospective analysis revealed that each patient had been hyperthermic during the time of aortic cross-clamping. It is possible that the hyperthermia, either alone or in combination with other factors, contributed to the development of paraplegia in these three infants.
The "premedical syndrome" has been widely discussed but only anecdotally described. To learn whether the syndrome exists in the South Carolina schools and which traits compose it, the authors surveyed faculty members and students of 13 undergraduate colleges in the state. Premedical students were perceived as differing from nonpremedical students in being excessively competitive, academically, overspecialized , overachieving , more highly motivated, more highly self-disciplined, goal-oriented, and proud of their career choice. The perception by students and faculty members of the premedical syndrome may have important effects on the undergraduate curriculum and students' choices of major areas of study. Only 3 percent of the premedical students who responded to the survey were majoring in the liberal arts, and only 9 percent of the nonpremedical students were majoring in the natural sciences. These data suggest that the natural science departments in U.S. colleges may have become training grounds for premedical students to the exclusion of others. Modification of medical school admissions policies may be able to reverse some features of the premedical syndrome and some of its effects.
We have used the St. Jude Medical cardiac valve prosthesis without postoperative anticoagulation in 34 children undergoing valve replacement since March, 1979. The 19 boys and 15 girls ranged in age from 9 months to 21 years. The valve replaced was mitral in 12 patients, aortic in 14, pulmonary in three, and both mitral and aortic in two. One patient had implantation of a St. Jude Medical valve in a pulmonary conduit, and a left-sided tricuspid valve was replaced in two children. There were three operative deaths, all in infants with complex disease. One patient died suddenly at home 5 weeks after valve replacement, probably of ventricular arrhythmia. During follow-up of 1 to 50 months, comprising 646 patient months, no thromboembolic complications have been observed. Although use of the St. Jude Medical prosthesis without anticoagulation is still investigational, our preliminary data suggest that the risk of thromboembolism in unanticoagulated children with this valve is not greater than that in anticoagulated adults. The results justify continuing investigation of the St. Jude Medical prosthesis in children without postoperative anticoagulation.
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The suitability of absorbable suture for atrial repair was tested in 25 rabbits in which atrial wounds were repaired with either polyglycolic acid or polypropylene suture. Tensile strength and wound thickness were measured at several time intervals up to 8 weeks after wounding. With each animal used as its own control, the ratio of wound tensile strength to that of unwounded atrium and of wound thickness to thickness of unwounded atrium were compared at several time intervals. There was no difference between polyglycolic acid and polypropylene suture lines in tensile strength index, but the wall thickness index was significantly lower for polyglycolic acid sutures. The latter finding was probably due to a less intense chronic inflammatory response in the polyglycolic acid group. Because of the necessity for maximal size and future growth of atrial anastomoses after repair of some congenital cardiac malformations, polyglycolic acid suture appears to be a reasonable alternative to nonabsorbable suture for atrial repair in children.
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