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Biomedical subjects

M D Clark

Publications and source records attributed to M D Clark.

At least 19 recordsLinked to original sources
PubMed1992

Amaurosis fugax: is it innocuous?

A 10 year retrospective study of 103 patients with amaurosis fugax was done. Sixty-two patients with symptoms of amaurosis fugax underwent arteriography, which demonstrated ulcerated carotid plaque in 36 and hemodynamically significant stenoses (greater than 75% diameter reduction) in 26. These 62 patients underwent carotid endarterectomy. The other 41 patients who had proven ulcerated plaque (33 patients) or hemodynamic stenoses (eight patients) were not treated surgically and served as a control series. No strokes or deaths occurred in the immediate postoperative period. Follow-up of the 62 operated patients extending to 10 years (mean 4.2 years), revealed one (1.6%) patient with recurrent amaurosis fugax symptoms, two (3.2%) with transient ischemic attacks, and one (1.6%) with a stroke in the operated hemisphere. In the nonoperated group, despite aspirin or warfarin treatment, four (9.7%) patients had ongoing amaurosis fugax symptoms, and two (4.8%) developed transient ischemic attacks that led to carotid endarterectomy. One (2.4%) other patient developed sudden, permanent monocular blindness, and two (4.8%) suffered hemispheric strokes, one of which was fatal. The cumulative morbidity (ongoing ocular or transient ischemic attack symptoms, perioperative and late stroke) in the operated group was 6.4% (four patients), while the cumulative morbidity in the nonoperated group was significantly higher at 21.9% (nine patients) (p = 0.02). When patients present with symptoms of amaurosis fugax and have demonstrable carotid bifurcation disease, carotid endarterectomy is recommended. Amaurosis fugax should be regarded as a harbinger of monocular blindness and stroke.

Adult↗
PubMed1991

When the same is different. A comparison of the information processing strategies of deaf and hearing people.

In this study, the information processing strategies of Gallaudet University students who are profoundly and prelingually deaf were evaluated. The subjects demonstrated the highest levels of recognition to the left and right of the fixation point, often referred to as a reading strategy when found in hearing people. Additionally, they demonstrated higher levels of recognition at positions in the top right quadrant of the display, a pattern not found in hearing people. A main effect was found: subjects whose primary and secondary school backgrounds were oral and manual combined had significantly higher levels of recognition overall than did subjects from oral-only educational backgrounds. Differences in background did not interact with strategy use in this study. These findings lead to the conclusion that the information processing strategies of deaf people need to be evaluated closely before general conclusions can be made. Alternative means for evaluating these types of findings are suggested.

Adult↗
PubMed1990

Case report 589: Use of Ostamer in fusion of lumbar spine, postoperative appearance.

In the late 1950s and early 1960s there was intense orthopedic interest in a plastic polyurethane foam (Ostamer) that could be used in the fixation of fractures, performance of arthrodesis, and in spinal fusions. It saw limited success at that time but eventually fell from favor. A patient presenting with a draining sinus in the buttock, back pain, and a history of lumbar spinal fusion with Ostamer was recently scanned in our department. The CT appearance of Ostamer and a brief review of the literature are reported.

Bone Cements↗
PubMed1990

Carotid patch angioplasty: immediate and long-term results.

To determine the benefit of carotid patch angioplasty, a retrospective study of 1000 consecutive carotid endarterectomies was done. Based on the type of carotid endarterectomy closure, patients were divided into four groups: 250 had primary closure, 250 had expanded polytetrafluoroethylene patch, 250 had Dacron patch, and 250 had saphenous vein patch. On the basis of operative technique or type of carotid artery closure, no statistical difference was found in the incidence of postoperative stroke (p greater than 0.25): primary closure 1.6% (4), expanded polytetrafluoroethylene 2.0% (5), Dacron patch 1.6% (4), and saphenous vein patch (0). Postoperative carotid patency was determined by B-mode ultrasonography, and 717 patients were evaluated in follow-up extending to 6 years (mean 37.8 months). Based on the method of carotid endarterectomy closure, no significant difference (p greater than 0.25) was found in the incidence of significant restenosis (greater than 50% diameter reduction): primary closure 4.0% (7), expanded polytetrafluoroethylene 4.0% (6), Dacron 5.4% (9), and saphenous vein 1.0% (2). Significant restenosis was most frequent in habitual smokers (93%, 25/28) and females (78%, 22/28) despite the method of carotid endarterectomy closure. No statistical difference was found in the incidence of late ipsilateral stroke either (p greater than 0.25): primary closure 2.9% (5), expanded polytetrafluoroethylene 2% (3), Dacron 5% (3), and saphenous vein 0%. These results indicate that the incidence of postoperative stroke, regardless of method of arterial closure, was not statistically different. The method of carotid closure did not appear to affect the occurrence of late ipsilateral stroke or restenosis; however, patch angioplasty with saphenous vein appears appropriate in habitual smokers, and likely in patients with small internal carotid arteries.

Blood Vessel Prosthesis↗
PubMed1989

Massive pulmonary embolism: triple-armed therapy.

Many patients who suffer a massive pulmonary embolus die despite emergent therapy. In these desperately ill patients an aggressive, combined method of management was initiated to improve their chances and quality of survival. During a 5-year period 10 patients were treated with (1) low-dose topical, intrapulmonary thrombolytic therapy to dissolve thrombus, (streptokinase or urokinase); (2) anticoagulation to prevent thrombus propagation (heparin); and (3) the simultaneous insertion of a Greenfield filter to prevent the early, recurrent, and therefore potentially fatal pulmonary embolus--"triple-armed therapy." Thrombolytic therapy was administered through a Swan-Ganz catheter wedged against the pulmonary embolus. During the same interval 10 other patients also sustained massive pulmonary emboli but were treated only with systemic heparin. Serial pulmonary arteriography was performed daily. The patients treated by triple-armed therapy responded favorably with a rapid (less than 6 hours), significant improvement in PaO2, pulmonary artery pressure, cardiac output, pulmonary vascular resistance, and blood pressure, compared with patients treated with continuous heparin alone. Nine patients in the triple-armed therapy group survived whereas only six in the heparin group survived. Two additional patients were treated by triple-armed therapy and had thrombolysis with triple-armed therapy with tissue plasminogen activator; these patients demonstrated the most rapid improvement in cardiorespiratory dynamics and arteriographic clearance of emboli. This management protocol shows promise for patients who sustain a massive pulmonary embolus, because it reduces the morbidity associated with pulmonary embolectomy while avoiding the hazards associated with systemic thrombolytic therapy.

Aged↗
PubMed1989

Preventing drug dependency: Part 2, Educating and supporting staff.

Nurse administrators can respond to the chemical abuse problem in one of two ways. They can deny it, ignore it, avoid confrontation, and terminate the employee. Such action jeopardizes both the nurse and patients. Alternatively, nurse administrators can deal with the problem by recognizing its prevalence in society, educating their personnel, providing support systems for staff, and establishing controls. By choosing this latter course of action, nurse managers evidence humanity and concern for patients, the profession, and individual practitioners.

Career Mobility↗
PubMed1988

Carotid endarterectomy after reversible ischemic neurologic deficit or stroke: is it of value?

The benefit of carotid endarterectomy (CE) in preventing recurrent stroke and improving survival in the patient who has sustained a reversible ischemic neurologic deficit (RIND) or stroke is still controversial. To determine the long-term benefits and value of CE in these patients, a 10-year review of 253 patients who suffered a RIND or stroke was conducted. All patients had CT brain scans, as well as arch, extracranial, and intracranial arteriography; any patients without demonstrated carotid bifurcation disease were excluded from the study. On the basis of clinical symptoms and CT scan findings, 66 patients were categorized as having sustained a RIND and 187 a stroke. One hundred fifty-one patients who suffered a RIND or stroke had CE, whereas 102 patients with RIND or stroke did not have CE and served as a control group. All endarterectomies were performed with a temporary indwelling shunt. Postoperative complications included two deaths (1%), six strokes (4%), and 10 transient neurologic deficits (7%). In follow-up extending to 10 years the cumulative incidence of recurrent stroke was only 7% (11 patients) in the operated group, whereas 18% of patients in the nonoperated control group (18) sustained a recurrent stroke (p less than 0.05). As anticipated, the leading cause of death during follow-up was cardiac related; although CE did not significantly improve long-term survival, there was more than a twofold decrease in the incidence of recurrent stroke as a cause of death in the group having CE.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

Preventing drug dependency: Part I, Recognizing risk factors.

Nurse administrators are in a key position to develop strategies to deter drug abuse by their staff. This two-part series of articles discusses the development of a prevention program. This first article describes risk factors associated with initial and continuing drug use by nurses. The second article (January 1989) will present an educational program based on these risk factors and suggest ways to provide staff with support.

Attitude of Health Personnel↗
PubMed1987

Carotid endarterectomy to correct asymptomatic carotid stenosis: ten years later.

The ideal management of the patient with an asymptomatic stenosis of the extracranial internal carotid artery remains controversial. The purpose of this article was to evaluate the effects of prophylactic carotid endarterectomy (CE) done to treat asymptomatic carotid stenosis (greater than 50% diameter reduction by angiography) 10 years later. In 1976, 42 prophylactic CEs were performed. There were no postoperative deaths or strokes. During 10-year follow-up two strokes occurred in the operated hemisphere; one stroke was fatal and was due to an intracranial hemorrhage, whereas the other stroke was thromboembolic in origin. Two other patients suffered strokes in the contralateral hemisphere and seven patients had transient ischemic attacks in the contralateral hemisphere, which necessitated CE. The survival rate at the end of the study period by life-table analysis was 57% (mean 8.7 years). Sixteen late deaths occurred, with coronary artery-related disease the most common cause of death. This review with actual 10-year follow-up demonstrated that prophylactic CE may be performed with minimal risk, that late stroke in the operated hemisphere was negligible, and that long-term survival was similar to that of a comparable age-matched population, possibly because late deaths attributed to stroke were reduced. On the basis of long-term follow-up, CE to treat asymptomatic high-grade carotid stenoses appears to be indicated in appropriate patients.

Actuarial Analysis↗
PubMed1987

Traumatic superior mesenteric arteriovenous fistula: report of a case and review of the literature.

Penetrating arterial injuries can result in the formation of a traumatic false aneurysm or an arteriovenous fistula. Traumatic arteriovenous fistulas of the mesenteric circulation are extremely rare, with only 15 operated cases reported in the English language literature that involved the superior mesenteric artery and vein. Although surgical intervention has been considered the most successful method to treat traumatic mesenteric arteriovenous fistulas, percutaneous transcatheter embolization has been occasionally advocated in the management of small iatrogenic fistulas. We report a case of a gunshot wound patient who had an 8 cm abdominal aortic false aneurysm, as well as a high-flow arteriovenous communication between the superior mesenteric artery and vein, which were successfully treated by a combination of aorto-superior mesenteric bypass and postoperative percutaneous transcatheter embolization. A review of the literature is also included.

Adolescent↗
PubMed1987

Prevention of postoperative neurologic deficits after carotid endarterectomy. Is platelet inhibition beneficial?

Aspirin (ASA) and dipyridamole (DIP) have been shown to reduce the incidence of transient ischemic attacks (TIAs), but aspirin's ability to reduce the incidence of postoperative neurologic deficits in patients who require carotid endarterectomy (CE) is controversial. To evaluate the role of adjunctive ASA/DIP in conjunction with CE, 908 CE cases were reviewed. Four hundred sixty-seven patients took ASA (650 mg/day) and DIP (150 mg/day) preoperatively, while 381 received no ASA/DIP. There was no statistical difference in the distribution of postoperative neurologic deficits. Twenty-six transient deficits occurred: 14 (53%) patients were taking ASA/DIP, whereas 12 (47%) were not. Seventeen permanent deficits occurred: ten (58%) patients were taking ASA/DIP and seven (42%) were not. ASA/DIP are useful medications in combating ischemic cerebrovascular disease, but ASA/DIP cannot replace precise operative technique which affords unequaled protection against a postendarterectomy neurologic deficit.

Adult↗
PubMed1986

Carotid endarterectomy in the octogenarian: is it appropriate?

To evaluate the role of carotid endarterectomy (CE) in patients 80 years and older an 8-year study of 172 nonrandomized cases of octogenarians with cerebrovascular disease was done. Ninety octogenarians underwent CE whereas 82 octogenarians, with arteriographically established carotid artery disease, were not operated on and served as a control series. The stroke rate after CE was 6%. In follow-up extending to 8 years the late stroke rate was only 2%, whereas the cumulative long-term stroke rate in the nonoperated group was 16%. These late strokes were appropriate to the side of the arteriographically demonstrated disease. In 1008 nonoctogenarians who underwent CE during this same time interval, the stroke rate after CE was 2% and the mortality rate was 0.6%. In the octogenarian population, however, the mortality rate after stroke was an alarming 40% in the operated group and 62% in the nonoperated control group. Arteriographic flow-limiting (greater than 75% stenosis) intracranial occlusive disease was identified in 53% of the octogenarians undergoing operation and in all patients who suffered a postoperative neurologic deficit. This incidence of severe intracranial disease was nearly five times that of the nonoctogenarian patients undergoing CE. Although the stroke rate after CE in the octogenarian patient was 6%, the late stroke rate was only 2% compared with the cumulative stroke rate of 16% in the nonoperated octogenarian patients. Severe intracranial occlusive disease and, therefore, flow deprivation may play a more significant role as a cause of postoperative deficits than in younger patients, but CE is appropriate for selected octogenarians on the basis of physiologic rather than chronologic age.

Actuarial Analysis↗
PubMed1986

Unifying nursing.

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Education, Nursing↗