Biomedical subjects

R C Gorman

Publications and source records attributed to R C Gorman.

11 recordsLinked to original sources

PubMed1996

Dynamic three-dimensional imaging of the mitral valve and left ventricle by rapid sonomicrometry array localization.

OBJECTIVES: The first objective was to develop a quantitative method for tracking the three-dimensional geometry of the mitral valve. The second was to determine the complex interrelationships of various components of the mitral valve in vivo. METHODS AND RESULTS: Sixteen sonomicrometry transducers were placed around the mitral vale anulus, at the tips and bases of both papillary muscles, at the ventricular apex, across the ventricular epicardial short axis, and on the anterior chest wall before and during cardiopulmonary bypass in eight anesthetized sheep. Animals were studied later on 17 occasions. Reproducibility of derived chord lengths and three-dimensional coordinates from sonomicrometry array localization, longevity of transducer signals, and the dynamics of the mitral valve and left ventricle were studied. Reproducibility of distance measurements averages 1.6%; Procrustes analysis of three-dimensional arrays of coordinate locations predicts an average error of 2.2 mm. Duration of serial sonomicrometry array localization signals ranges between 60 and 151 days (mean 114 days). Sonomicrometry array localization demonstrates the saddle-shaped mitral anulus, its minimal orifice area immediately before end-diastole, and uneven, apical descent during systole. Papillary muscles shorten only 3.0 to 3.5 mm. Sonomicrometry array localization demonstrates nonuniform torsion of papillary muscle transducers around a longitudinal axis and shows rotation of papillary muscular bases toward each other during systole. CONCLUSION: Tagging of ventricular structures in experimental animals by sonomicrometry array localization images is highly reproducible and suitable for serial observations. In sheep the method provides unique, quantitative information regarding the interrelationship of mitral valvular and left ventricular structures throughout the cardiac cycle.

Animals↗

PubMed1996

Surface-bound heparin fails to reduce thrombin formation during clinical cardiopulmonary bypass.

The hypothesis that heparin-coated perfusion circuits reduce thrombin formation and activity; fibrinolysis; and platelet, complement, and neutrophil activation was tested in 20 consecutive, randomized adults who had cardiopulmonary bypass. Twenty identical perfusion systems were used; in 10, all blood-contacting surfaces were coated with partially degraded heparin (Carmeda process; Medtronic Cardiopulmonary, Anaheim, Calif.). All patients received a 300 U/kg dose of heparin. Activated clotting times were maintained longer than 400 seconds. Cardiopulmonary bypass lasted 36 to 244 minutes. Blood samples for platelet count, platelet response to adenosine diphosphate, plasma beta-thromboglobulin, inactivated complement 3b, neutrophil elastase, fibrinopeptide A, prothrombin fragment F1.2, thrombin-antithrombin complex, tissue plasminogen activator, plasminogen activator inhibitor-1, plasmin alpha 2-antiplasmin complex, and D-dimer were obtained at these times: after heparin was given, 5 and 30 minutes after cardiopulmonary bypass was started, within 5 minutes after bypass was stopped, and 15 minutes after protamine was given. After cardiopulmonary bypass, tubing segments were analyzed for surface-adsorbed anti-thrombin, fibrinogen, factor XII, and von Willebrand factor by radioimmunoassay. Heparin-coated circuits significantly (p < 0.001) reduced platelet adhesion and maintained platelet sensitivity to adenosine diphosphate (p = 0.015), but did not reduce release of beta-thromboglobulin. There were no significant differences between groups at any time for fibrinopeptide A, prothrombin fragment F1.2, or thrombin-antithrombin complex or in the markers for fibrinolysis: D-dimer, tissue plasminogen activator, plasminogen activator inhibitor-1, and alpha 2-antiplasmin complex. In both groups, concentrations of prothrombin fragment F1.2 and thrombin-antithrombin complex increased progressively and significantly during cardiopulmonary bypass and after protamine was given. Concentrations of D-dimer, alpha 2-antiplasmin complex, and plasminogen activator inhibitor-1 also increased significantly during bypass in both groups. Fibrinopeptide A levels did not increase during bypass but in both groups increased significantly after protamine was given. No significant differences were observed between groups for levels of inactivated complement 3b or neutrophil elastase. Radioimmunoassay showed a significant increase in surface-adsorbed antithrombin on coated circuits but no significant differences between groups for other proteins. We conclude that heparin-coated circuits used with standard doses of systemic heparin reduce platelet adhesion and improve platelet function but do not produce a meaningful anticoagulant effect during clinical cardiopulmonary bypass. The data do not support the practice of reducing systemic heparin doses during cardiac operations with heparin-coated extracorporeal perfusion circuitry.

Anticoagulants↗

PubMed1995

Pathogenesis of acute ischemic mitral regurgitation in three dimensions.

Changes in the geometric and intravalvular relationships between subunits of the ovine mitral valve were measured before and after acute posterior wall myocardial infarction in three dimensions by means of sonomicrometry array localization. In 13 sheep, nine sonomicrometer transducers were attached around the mitral anulus and to the tip and base of each papillary muscle. Five additional transducers were placed on the epicardium. Snares were placed around three branches of the circumflex coronary artery. One to 2 weeks later, echocardiograms, dimension measurements, and left ventricular pressures were obtained before and after the coronary arteries were occluded. Data were obtained from seven sheep. Coronary occlusion infarcted 32% of the posterior left ventricle and produced 2 to 3+ mitral regurgitation by Doppler color flow mapping. Multidimensional scaling of dimension measurements obtained from sonomicrometry transducers produced three-dimensional spatial coordinates of each transducer location throughout the cardiac cycle before and after infarction and onset of mitral regurgitation. After posterior infarction, the mitral anulus enlarges asymmetrically along the posterior anulus, and the tip of the posterior papillary muscle moves 1.5 +/- 0.3 mm closer to the posterior commissure at end-systole. The posterior papillary muscle also elongates 1.9 +/- 0.3 mm at end-systole. The left ventricle enlarges asymmetrically and ventricular torsion along the long axis changes. The development of postinfarction mitral regurgitation appears to be the consequence of multiple small changes in ventricular shape and contractile deformation and in the spatial relationship of mitral valvular subunits.

Animals↗

PubMed1995

Difficult access problems.

We have described numerous alternatives for establishing central venous access in challenging patients. Using these techniques has proven successful in our experience in essentially all patients, although occasionally initial efforts fail and repeated attempts by alternate routes are required. The keys to eventual success appear to be good basic surgical skills, a strong working relationship between surgeon and interventional radiologist, and perhaps most important, perseverance in the face of frustration.

Catheterization, Central Venous↗

PubMed1994

Esophageal disease in the elderly patient.

Disorders of the esophagus in elderly patients are usually associated with the classic symptoms of dysphagia, regurgitation, chest pain, and heartburn. Pulmonary complaints as a result of undiagnosed esophageal disease are common in this age group. Diagnosis is often delayed because symptoms are attributed to underlying cardiac and pulmonary disease. Elderly patients are more susceptible to the complications of aspiration and malnutrition that often accompany inadequately treated esophageal disease; therefore, prompt and aggressive treatment is indicated. Criteria for surgical intervention in esophageal disease do not change with age. Properly selected elderly patients tolerate esophageal surgery well. Age alone should not constitute a contraindication to surgery of the esophagus.

Aged↗

PubMed1993

Enteroenteric intussusception due to a metastatic malignant fibrous histiocytoma.

Intussusception secondary to metastatic sarcoma is an unusual cause of small bowel obstruction. When a patient who has no history of a previous laparotomy, and has a known malignancy which metastasized hematogenously, presents with small bowel obstruction, the diagnosis of intussusception should be considered. The patient should be evaluated and treated accordingly.

Female↗

PubMed1991

Multivitamin prophylaxis in prevention of post-gastric bypass vitamin and mineral deficiencies.

One hundred forty patients were followed for a mean 24.2 months after gastric bypass. Postop multivitamin (MV) prophylaxis was recommended for all patients and 90 of 140 patients (64 percent) were regularly compliant. Deficiencies in iron, vitamin B-12 or folate were recognized in 88 of 140 patients (63 percent). Thirty of 45 patients (67 percent) with iron deficiency developed anemia. Forty-three of the 52 patients who did not have deficiencies were regularly taking MV vs 47 of 88 patients who developed deficiencies (P less than 0.001). MV prophylaxis was successful in preventing folate (P less than or equal to 0.05) and vitamin B-12 deficiencies (P less than or equal to 0.02) but did not prevent development of iron deficiency or subsequent anemia. There was no correlation between taking prescribed supplements and resolution of either iron deficiency of anemia. B-12 and folate supplements corrected deficiencies in 73 percent of cases. We conclude that oral MV prophylaxis is useful in preventing folate and B-12 deficiency after gastric bypass. Additional prophylactic iron supplements should be provided for women to prevent iron deficiency and associated anemia.

Anastomosis, Roux-en-Y↗

PubMed1989

The dilemma of outcome assessment after operations for morbid obesity.

Outcome of 56 patients who underwent horizontal gastroplasty (HGP) and 126 who underwent Roux-en-Y gastric bypass (RYGB) was assessed at 18 months postoperatively according to three definitions of successful weight loss; also, outcome was evaluated in the context of amelioration of obesity-related medical problems. Outcome definitions included the following: I, loss of 25% or more of preoperative weight; II, loss of 50% or more of excess weight; III, loss to within 50% of ideal body weight. To evaluate the impact of preoperative weight on success rate, patients were divided into two weight groups: "morbidily" obese patients, who were 100 to 199 pounds overweight (n = 146), and "super"-obese patients who were 200 pounds or more overweight (n = 36). Weight loss was significantly greater with RYGB versus HGP by each of the three definitions of success. Medical problems either improved or resolved with weight loss in 95% of cases. There were statistically significant differences in success rate depending on outcome definition in both HGP and RYGB patients. Success rate ranged from zero in super-obese HGP patients by Definition III to 97% in super-obese RYGB patients by Definition I. Although super-obese patients lost more pounds than the lighter morbidly obese patients, a significantly lower number of super-obese patients lost within 50% of ideal weight. Super-obese patients must lose more weight to reduce their actuarial risk. These results show that the definition of successful outcome may significantly influence the overall success rate in a large series of bariatric surgical patients.

Adolescent↗

PubMed1988

Baroreceptor responses derived from a fundamental concept.

A model is presented that relates the change in baroreceptor firing rate to a step change in blood pressure. This relationship is nonlinear since the alteration in rate of firing depends on the current rate of firing. It is shown that this simple relationship embodies all currently established baroreceptor response modes. The model needs refinement to allow for effects arising from the properties of the tissue matrix in which the receptors are embedded. Further analysis is precluded at present owing to paucity of quantitative experimental data.

Animals↗

PubMedDate not supplied

The button jejunostomy for long-term jejunal feeding: results of a prospective randomized trial.

Low profile, self-retaining feeding conduits ("buttons") inserted percutaneously through a mature gastrostomy stoma are ideal for prepyloric feeding. We tested the efficacy of a surgically inserted button (Button, C.R. Bard, Inc) in the jejunum for long-term postpyloric feeding. Forty-two aspiration risk patients were prospectively randomized to receive a standard No. 14 French red rubber catheter (n = 21, mean age 68 +/- 17 years) or the button (n = 21, mean age 68 +/- 18 years). Common indications for jejunal feeding were aphagia due to obtundation (41%) and esophageal dysmotility (41%). All feeding devices were inserted 20 cm distal to the ligament of Treitz via a serosal tunnel (catheter) or double pursestring (button) technique. No patient required reoperation, and cardiopulmonary failure was the most frequent cause of death, occurring in 11 patients (26%). Goal feedings were obtained in 91% of the catheter patients and 100% of the button patients by postoperative day 4.7 +/- 1.9 and 4.2 +/- 2.2, respectively. At a follow-up of 43 +/- 13 days, 12 (92.3%) of 13 catheter patients and 9 (81.8%) of 11 button patients were receiving goal feedings. Three patients in the catheter group and four patients in the button group had resumed an oral diet. Device-related complications (dislodgment, occlusion, peritubular leak, or bowel obstruction) and total number of patients with complications were significantly lower in the button group (one [5%] vs eight [38%] for device-related complications and one [5%] vs six [29%] for incidence of complications for the button and catheter groups, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

Use of nutrition support in patients with AIDS: a four-year retrospective review.

A series of 55 patients with AIDS and opportunistic infections were admitted a total of 75 times to Robert Wood Johnson University Hospital over a 4-year period, and supplemental nutrition support--intravenous (IV), enteral, or both--was given during 32 of these admissions. Use of nutrition support was correlated retrospectively with pretreatment nutritional status, length of hospital stay (LOS), and survival and was found to be positively correlated with weight loss greater than or equal to 10% or weight less than or equal to 90% of ideal body weight (p less than 0.001), admission hemoglobin less than or equal to 10g (p less than 0.001), and LOS less than or equal to 21 days (p less than or equal to 0.003). Nutrition support intervention did not correlate with survival, admission total lymphocyte count (TLC), or serum albumin level. Survival was negatively correlated with LOS (p less than or equal to 0.04) and continuous daily fever for greater than or equal to 6 days (p less than 0.001). Survival was also significantly lower in patients who received IV rather than enteral nutrition support (p less than or equal to 0.03). Weight loss, admission TLC, albumin, and hemoglobin levels did not correlate with survival. These results suggest that nutrition support generally was given to the sickest patients with AIDS. There was no measurable benefit associated with use of supplemental nutritional support in this series. Properly designed trials will be necessary to define the optimum route, timing, and type of nutritional support for patients with AIDS.

Acquired Immunodeficiency Syndrome↗