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Biomedical subjects

L D MacLean

Publications and source records attributed to L D MacLean.

At least 19 recordsLinked to original sources
PubMed1990

Assessment of cardiac function in patients who were morbidly obese.

Cardiac function of 30 patients who were morbidly obese was studied before bariatric surgery. Twelve patients were studied 13 +/- 4 months after surgery. These patients had a mean age of 37.1 +/- 2.9 years and a body mass index of 50.0 +/- 1.4 kg/m2. Cardiac function was measured by echocardiography, radionuclide angiography scanning, and right heart catheterization. To determine the degree of cardiac dysfunction, the patients were studied with exercise and intravenous fluid challenges. Ultrasonography produced evidence of myocardial thickening with an increased interventricular septum in eight patients (32%) and increased left ventricular mass in 17 patients (53%). The radionuclide scan suggested that morbid obesity was associated with a significantly (p less than 0.05) increased end-diastolic volume and decreased left ventricular ejection fraction as compared with patients who were of normal weight. With exercise the patient who was of normal weight had an increase in the end-diastolic volume, stroke volume, and heart rate, but the patient who was morbidly obese only increased heart rate to produce the necessary increase in cardiac output. Right heart catheterization indicated that the relationship of the pulmonary wedge pressure and the left ventricular stroke work index was abnormal in 14 of 29 patients (48.3%) and depressed in six of 29 patients (20.7%) with exercise. One liter of fluid caused an abnormal relationship of the pulmonary wedge pressure and the left ventricular stroke work index in 12 of 30 patients (40%) and a depressed response in 10 of 30 patients (33.3%). Cardiac studies were repeated in 12 patients after a 54.8 +/- 1.9 kg weight loss. Echocardiography indicated a decrease in dilatation (27.3% to 9.1%) and a significant (p less than 0.05) decrease in hypertrophy (45.5% to 0%). After the weight loss, radionuclide and right heart catheterization studies indicated improved cardiac function with reduced filling pressures and increased left ventricular work during fluid and exercise challenges. These results support the presence of obesity-related cardiomyopathy with ventricular dysfunction, which appears to be caused by a noncompliant ventricle. Significant weight loss achieved with gastroplasty results in increased ventricular compliance and improved cardiac function.

Adult↗
PubMed1990

Late results of vertical banded gastroplasty for morbid and super obesity.

Two hundred one patients who underwent vertical banded gastroplasty have been followed up for a minimum of 2 years to more than 5 years. Staple line perforations occurred in 48% of patients, and 36% underwent reoperation. The instability of the operation becomes apparent only with careful follow-up. More than 50% of patients who maintained a small orifice of less than or equal to 11 mm in diameter and an intact staple line over 3 to 5 years achieved an excellent result (0% to 25% excess weight), which equals the best results in the literature for any gastric-limiting operation, whether bypass or gastroplasty. The results of this operation for super obesity (a body mass index greater than or equal to 50 kg/m2) are disappointing. Only 8% of these patients achieve an excellent result. Failure of vertical banded gastroplasty in the morbidly obese (body mass index of 40 to 50 kg/m2) is frequently technical, and a method that eliminates dependence on integrity of staples should be evaluated. Results should be reported so that unsatisfactory results are apparent. Mean weight loss and mean percent excess weight loss are both highly satisfactory in this study, whereas unsatisfactory results ranged from 10% to 21% for each of the 5 years of follow-up.

Body Mass Index↗
PubMed1989

Antibiotic prophylaxis for surgery in morbidly obese patients.

The rate of wound infections in morbidly obese patients who underwent gastroplasty surgery at our institution was 16.5% compared with a rate of 2.5% in normal-weight patients who underwent clean-contaminated surgery. Both groups received 1 gm of cefazolin intramuscularly before surgery was performed. We hypothesized that this regimen of prophylaxis did not provide adequate tissue levels in the morbidly obese. Morbidly obese patients who were undergoing gastroplasty were randomly selected to receive 1 gm cefazolin in the buttock fat, buttock muscle, or by intravenous injection. A fourth group of morbidly obese patients received 2 gm of cefazolin intravenously. Normal-weight patients who were undergoing upper abdominal surgery received 1 gm of cefazolin intravenously. At incision and closure, both blood and tissue levels of cefazolin were significantly (p less than 0.001) lower for all morbidly obese patients who received 1 gm cefazolin when compared with the blood and tissue levels of the drug found in normal-weight patients. The cefazolin levels obtained were below the minimal inhibitory concentrations of greater than 2 micrograms/ml for gram-positive cocci and of greater than 4 micrograms/ml for gram-negative rods. Only when the morbidly obese patient received 2 gm cefazolin were both the serum and adipose tissue levels adequate. For a 4-month period, all morbidly obese patients received 2 gm cefazolin prophylaxis, and the wound infection rate dropped to 5.6% compared with the previous rate of 16.5% (p less than 0.03). We conclude that antibiotic prophylaxis must be specially tailored to the needs of these obese patients.

Adipose Tissue↗
PubMed1988

Shock.

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Humans↗
PubMed1988

Delayed type hypersensitivity testing in surgical patients.

DTH skin reactions can identify a population of surgical patients at increased risk for sepsis and related mortality. The usefulness of the technique is increased by repeating the test during the hospital course and by calculating a DTH score, which is the sum of the diameter of induration of all five or six tests expressed in millimeters. Regression analysis of factors that could possibly indicate development of sepsis and death after surgical treatment reveals that the most powerful predictors are serum albumin, DTH score and age of the patient. The population of patients who are anergic are more frequently malnourished than reactive patients, but the DTH response cannot be used to determine the malnourished state in individual patients. The lack of a DTH reaction (anergy) identifies an immune defect characterized by a failure of release of lymphokines in vivo. Lymphokines from normal individuals can restore to normal the absent response of anergic patients to specific antigens. In experimental animals made anergic by a heat injury, the mortality rate from bacterial peritonitis can be significantly lowered by lymphokines. Immunomodulation of demonstrated defects in host resistance is an exciting prospect for the future of surgical patients.

Animals↗
PubMed1988

Revision of failed horizontal gastroplasty by vertical banded gastroplasty.

Eighteen patients who had undergone horizontal gastroplasty experienced postoperative weight gain due to technical failure (large orifice in 10 patients, staple-line disruption in 7 and a large pouch in 1). A vertical banded gastroplasty was used to correct the problem, with a resulting operative morbidity of 38.9%. This included perforation with peritonitis (five patients) and complete outlet obstruction (two patients). These complications appear to result from poor blood supply to the area of the anastomosis necessary in this conversion. This study indicates that it is not safe to use vertical banded gastroplasty for the failed horizontal gastroplasty.

Adult↗
PubMed1987

Nutrition after vertical banded gastroplasty.

The authors assessed the nutritional status of 60 morbidly obese patients by determining body composition, using multiple isotope dilution at 13.6 +/- 0.4 months following operation. Body weight was followed for an additional 12.3 +/- 0.8 months. Twenty-four patients lost more than 25% of their preoperative weight and were within 30% of ideal weight (a "good" result). At 1 year they had lost 41.4 +/- 1.8% of preoperative weight and the body mass index (BMI) decreased from 46.7 +/- 1.2 to 27.0 +/- 0.6 kg/m2. Despite rapid weight loss, malnutrition did not develop and their body composition became indistinguishable from that of normally nourished volunteers. Twenty-nine patients had a "satisfactory" result with more than 25% weight loss but were not within 30% of ideal. Their weight decreased by 34.8 +/- 1.0% as their BMI decreased from 55.4 +/- 1.2 to 36.0 +/- 0.8 kg/m2. Seven patients lost less than 25% of their preoperative weight (an "unsatisfactory" result). Malnutrition did not develop in any patient. In the authors' experience, in contrast to other weight reducing operations, vertical banded gastroplasty (VBG) results in rapid weight loss without the concomitant development of malnutrition even in patients who return to normal weight.

Blood Chemical Analysis↗
PubMed1986

Abnormalities in the cellular phase of blood fibrinolytic activity in systemic lupus erythematosus and in venous thromboembolism.

Fibrinolytic activities of whole blood and plasma were determined by 125I-fibrin radiometric assay in 16 normal subjects, and in 11 patients with systemic lupus erythematosus (SLE), 14 with progressive systemic sclerosis (PSS), 23 with venous thromboembolic disease, and 20 patients awaiting elective surgery. Mean whole blood and plasma activities for patients with PSS, and for those awaiting elective surgery, were similar to normal values, as was the mean plasma activity in patients with SLE. However, mean whole blood activity in SLE was significantly decreased compared with normals (p less than 0.05), with mean plasma activity accounting for 44% of mean whole blood activity (compared with 17% in normal subjects), representing a 67% decrease in mean calculated cellular phase activity in SLE, when compared with normals. Since the numbers of cells (neutrophils, monocytes) possibly involved in cellular activity were not decreased, the findings suggest a functional defect in fibrinolytic activity of one or more blood cell types in SLE. An additional finding was the participation of the cellular phase as well as the well-known plasma phase of blood in the fibrinolytic response to thromboembolism.

Female↗
PubMed1985

Shock. A century of progress.

The word shock has been used for at least a century in all clinical disciplines to describe a progressive but gradual collapse of vital organ functions. Important initial steps in understanding the problem began at the turn of the century by two means: clear clinical descriptions and the initiation of research into etiology and treatment. The growth of shock treatment and its promising future are discussed.

Blood Volume↗
PubMed1985

Significance of immunoreactivity in trauma.

Anergy is a crude measure of host resistance which may be due to malnutrition, but is probably more often due to inappropriate host responses to surgery and injury. Severe injury and infection decrease chemotaxis and the migration of neutrophils to areas of irritation. Lymphocytes from anergic patients are not properly functional in the DTH reaction, probably because of circulatory inhibitors in vivo. These lymphocytes can elicit a response when cultured in normal serum in vitro. B cell function is also impaired in anergic patients in that they do not respond to tetanus toxoid in vivo or in vitro. There is no randomized study which shows conclusively that one should delay elective surgery in anergic patients who are malnourished. Active immunization may become a reality in the prevention of surgical infections. Immunomodulators which favourable affect T and B cell function may also become a part of our armamentarium.

Antigen-Antibody Reactions↗
PubMed1985

State of the art.

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Anti-Bacterial Agents↗