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Biomedical subjects

R W Barnes

Publications and source records attributed to R W Barnes.

At least 73 records · Page 4Linked to original sources
PubMed1990

Crohn's disease in black patients.

Crohn's disease is less prevalent in blacks than in whites. However, when it does occur, it is associated with a high degree of morbidity and is frequently unrecognized at initial presentation. Forty-three patients with Crohn's disease presented to Howard University Hospital between 1965 and 1987. There were 156 hospital admissions, 47 emergency room visits, and 76 clinic visits over this 22-year period. Twenty-eight patients were female and 15 were male. The age of presentation for males ranged from 18 to 63 years and for females, 12 to 74 years. Crohn's disease should be considered in black patients who present with chronic abdominal pain and diarrhea. With correct diagnosis and appropriate medical therapy, patients should have an enhanced quality of life with less morbidity.

Adolescent↗
PubMed1989

Vasodilation and reduction in forearm vascular resistance after acute administration of dilevalol.

Dilevalol is a long-acting antihypertensive drug that has been demonstrated in animals to combine specific beta 2-agonist-mediated vasodilation with nonspecific beta blockade. To document vasodilation in humans, single oral doses of dilevalol, 200 mg, and placebo were randomly administered to 12 untreated hypertensive patients. Dilevalol produced significant reductions (p less than or equal to 0.01) in diastolic blood pressure throughout a 24-hour period relative to placebo, without changing heart rate. Forearm blood flow, measured hourly over the initial 4 hours after dosing, demonstrated a shift to a more vasodilated state after dilevalol administration, with significant increases in minimal forearm blood flow (4.0 vs 2.9 ml/dl tissue/min, dilevalol vs placebo, respectively; p = 0.05) and in mean average forearm blood flow (5.3 vs 4.0 ml/dl tissue/min, dilevalol vs placebo; p = 0.04). Similarly, dilevalol produced a decrease in mean forearm vascular resistance (26.5 vs 34.6 mm Hg/ml/dl tissue/min, dilevalol vs placebo; p = 0.02). In the absence of a change in heart rate, the acute hypotensive response to dilevalol in these patients appears to have resulted primarily from vasodilation and reduced vascular resistance.

Administration, Oral↗
PubMed1989

Understanding investigative clinical trials.

This article reviews the background, rationale, and principles of clinical trials and their role and influence on medical practice. The relationship of clinical trials to other forms of clinical studies is explored. The fundamentals of sound design, analysis, interpretation, and reporting of clinical trials are detailed. Ethical issues, costs, and limitations of trials are explored. The article reviews the trends in program content of 749 abstracts presented at the joint vascular surgical meetings during the past 17 years, demonstrating a significant increase in reported clinical trials during the last half of this period. Finally, future trends in the use of clinical trials to "validate" medical practice are suggested in response to efforts to control rising health care costs. Physicians, including vascular surgeons, must become knowledgeable in the principles of clinical trials to interpret more effectively, apply, or even participate in such clinical research.

Clinical Trials as Topic↗
PubMed1989

Halstedian technique revisited. Innovations in teaching surgical skills.

This paper reviews the laboratory models used to teach fundamental surgical skills in our general surgery residency. The laboratory modules allow supervision and self-instruction, practice, and videotape monitoring of the following techniques: skin incision, suturing, knot tying, hemostasis, vascular anastomosis, and intestinal anastomosis. Pigs' feet simulate human skin for exercises in skin incision, lesion excision, suturing, and basic plastic surgical techniques. Latex tubing and penrose drains allow experience in suturing, knot tying, and hemostasis. Polytetrafluoroethylene vascular prostheses permit quantification of the precision of needle passage and suturing by measurement of leakage of water through a vascular anastomosis. Reconstituted, lyophilized, irradiated bovine arteries and ileum provide models of biologic tissue for creating handsewn vascular anastomoses and sutured or stapled gastrointestinal anastomoses. A headlamp videocamera allows unobstructive recording of the resident's technical performance and provides subsequent visual feedback for self-improvement when compared to reference instructional videotapes. We feel that these innovations may enhance surgical dexterity of residents without the need for animal sacrifice. Our goal is to foreshorten the learning curve for basic surgical skills and improve performance in the clinical operating room.

General Surgery↗
PubMed1989

Serial noninvasive studies do not herald postoperative failure of femoropopliteal or femorotibial bypass grafts.

We performed a 5-year retrospective case-control study of 232 patients undergoing femoropopliteal (n = 188) or femorotibial (n = 44) bypass to determine if serial noninvasive studies herald postoperative graft failure. We correlated serial ankle/arm pressure indices (API) with graft patency. An interval drop in API of greater than or equal to 0.20 was considered hemodynamically significant, but interventional therapy was carried out only for clinically symptomatic graft failure and an API less than 0.20 above the preoperative value. The cumulative 5-year limb salvage rate was 82% and the patient survival was 63%. A significant drop in API did not correlate with cumulative 5-year graft patency. The 5-year cumulative primary graft patency rates were 60% and 62% in patients with stable and interval drops in API, respectively (Z = 0.15, p = N.S.) These results suggest that a significant drop in postoperative API does not predict patients with impending femoropopliteal or femorotibial graft failure. We believe that routine noninvasive surveillance and prophylactic intervention on detected asymptomatic lesions in leg bypass grafts may not be justified.

Adult↗
PubMed1989

Clinical and noninvasive assessment of venous disease as related to pulmonary embolism.

Proper management of patients with venous disease requires recognition of the various syndromes and an accurate objective diagnosis. Unfortunately many physicians are unfamiliar with the different venous disorders and are unaware of the fallibility of the clinical diagnosis of these syndromes. This article reviews the six common venous conditions that collectively are more common than coronary or peripheral arterial disease. Acute and recurrent deep vein thrombosis, postthrombotic syndrome, superficial thrombophlebitis, varicose veins, and pulmonary embolism may all confront the physician regardless of his or her specialty. Clinical recognition and differentiation of these disorders along with appropriate use of objective, noninvasive isotopic and venographic studies should lead to accurate diagnosis and management of these venous syndromes. Such an approach will permit prompt and appropriate therapy for disabling and potentially life-threatening venous thromboembolism while avoiding unnecessary anticoagulation of patients with disorders mimicking venous disease.

Acute Disease↗
PubMed1989

Perioperative asymptomatic venous thrombosis: role of duplex scanning versus venography.

We compared combined B-mode/Doppler (duplex ultrasonic scanning and venography in routine preoperative and postoperative screening for major proximal deep vein thrombosis in 78 patients undergoing total hip or knee arthroplasty. Of 309 extremity examinations, duplex scanning had an overall sensitivity of 85.7% (12/14) and a specificity of 97.3% (287/295). The preoperative prevalence and postoperative incidence of major deep vein thrombosis were 2.5% and 14.1% of patients, respectively, despite intensive mechanical and pharmacologic prophylaxis. In addition, venography documented a preoperative prevalence and postoperative incidence of isolated calf deep vein thrombosis in 2.5% and 16.7% of patients, respectively. Whereas such disease extended proximally even in the absence of anticoagulation in only 18% of patients studied by serial duplex scans, calf deep vein thrombosis accounted for the only two instances of pulmonary embolism in this study. There were no deaths related to pulmonary embolism. This study suggests that duplex scanning is useful in screening for perioperative deep vein thrombosis in patients undergoing total hip or knee arthroplasty, which carries a significant risk of venous thromboembolism despite routine prophylaxis.

Adult↗
PubMed1989

Multicenter trial of cadexomer iodine to treat venous stasis ulcer.

In a crossover study designed to judge the efficacy of the topical polymeric starch iodophore, cadexomer iodine, in accelerating the healing of venous stasis ulcers, 75 patients were prospectively randomly assigned to receive either cadexomer iodine or standard treatment. The control treatment consisted of a standard saline wet-to-dry compressive dressing. The patients improved with either treatment: ulcers healed more than twice as rapidly using cadexomer iodine (n = 38) as with standard therapy (n = 37) (P = .0025). Ulcers treated with cadexomer iodine showed trends toward less pain, exudate, pus, and debris, and a more rapid development of granulation tissue. Twelve patients crossed over from control treatment to the use of cadexomer iodine because of a failure to heal, but no patients switched to control therapy from the use of cadexomer iodine (P = .01). Except for occasional mild local burning in wounds treated with cadexomer iodine, no adverse effects were noted with either regimen.

Adult↗
PubMed1988

Mesoaortic compression of the left renal vein (the so-called nutcracker syndrome): repair by a new stenting procedure.

Compression of the left renal vein (LRV) between the superior mesenteric artery and the aorta has been termed the nutcracker syndrome. Although often asymptomatic, this syndrome may result in varicocele, ovarian vein syndrome, and rarely LRV hypertension, pelviureteral varices, hematuria, and flank pain. Previous surgical approaches have included nephrectomy, variceal ligation, nephropexy, or renocaval reimplantation. We report a new LRV stenting procedure that provided relief for a young woman incapacitated by daily left flank pain and microscopic hematuria. Phlebography of the LRV revealed mesoaortic compression associated with a pressure gradient of 12 mm Hg and preferential outflow down large pelviureteral varices. At operation compression of the LRV was corrected with an external stent of reinforced polytetrafluoroethylene. The patient was asymptomatic and free of hematuria for 9 months after operation and follow-up phlebography documented normal renocaval flow, elimination of the pressure gradient, and reduction of the pelviureteral varices. This represents the first description in the vascular surgical literature of this venous compression syndrome, which has been recognized in previous urologic and radiologic reports reviewed herein. Vascular surgeons should be cognizant of the nutcracker syndrome, and we recommend this new stenting procedure as a more simple and physiologic therapy than previous approaches to this problem.

Adolescent↗
PubMed1988

Laser thermal angioplasty for the treatment of obstruction of the distal superficial femoral or popliteal arteries.

The success rates and clinical effectiveness of percutaneous laser thermal angioplasty for obstruction of the distal superficial femoral or popliteal arteries were assessed. Laser thermal angioplasty was performed with the first commercially available laser system on 25 atherosclerotic vascular lesions in 20 lower extremities of 18 patients. Fifteen of the lesions were occlusions (average length, 5.6 +/- 3.1 cm), and 10 were high-grade stenoses (average length, 2.6 +/- 1.8 cm). Indication for angioplasty was claudication limiting life-style in 12 extremities and threatened limb loss in eight. All patients were treated with a 1.5- or 2.0-mm metal-capped optical fiber attached to a 14-W argon-ion laser. Balloon angioplasty was performed after laser recanalization in all successful cases. The patients were followed by Doppler ankle/brachial index and clinical evaluation. Laser thermal angioplasty was technically successful (vessel recanalization) in 18 (90%) of 20 of the cases. Fourteen (70%) of 20 extremities were successes by ankle/brachial index follow-up, while 15 (75%) of 20 remained clinically improved after an average follow-up of 7.8 +/- 5.3 months. Laser thermal angioplasty has a technical and clinical success rate that compares favorably with previous reports of balloon angioplasty. With proper patient selection, laser thermal angioplasty can reduce the difficulty of traversing lesions that are amenable to standard balloon angioplasty and increase the number of vascular lesions that can be treated percutaneously but could not be recanalized without the use of laser energy.

Aged↗
PubMed1988

The good ol' days is now: trends in operative experience of general surgical residents over 25 years.

To define the changing trends in operative experience of general surgery residents, the records of all residents completing our training program from 1964-1987 were reviewed. Except for a slight decline in operative experience in head and neck and gastric surgery, the experience in other primary component procedures either remained stable (major breast, esophagus, intestine, colon, pancreas, spleen and endocrine) or increased (minor breast, anorectal, hernia, biliary, vascular and trauma). A rich experience in secondary component procedures was maintained in thoracic, pediatric and plastic surgery, all of which are services within the department of surgery. A relatively low but stable experience in gynecology, neurosurgery, orthopaedics and urology has been reported, which did not change when these disciplines became separate departments. Finally, there has been a dramatic increase in endoscopic procedures performed in the surgery department despite the presence of endoscopic services in other departments. It is believed that such an institutional review of surgical resident caseload over time will be of help not only to program directors but also to accrediting and certifying organizations concerned with surgical training programs and their graduates.

Arkansas↗
PubMed1988

Replacement of the carotid artery using nonreversed saphenous vein.

Carotid artery replacement has been performed with a nonreversed saphenous vein in one patient who had carotid artery resection in association with resection of a squamous carcinoma at the carotid bifurcation. An excellent result was obtained. The technical aspects of this procedure are described herein.

Carcinoma, Squamous Cell↗