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Biomedical subjects

K McBride

Publications and source records attributed to K McBride.

46 records · Page 3Linked to original sources

Failure of carotid stump pressures. Its incidence as a predictor for a temporary shunt during carotid endarterectomy.

A total of 289 carotid endarterectomies were performed in 204 patients. A decision to place a temporary shunt during carotid endarterectomy in this series was made entirely on the basis of intraoperative EEG monitoring. Retrospectively, the correlation between stump pressures and the results of intraoperative EEG monitoring in each case was determined. Evidence of ischemia developed in 6% of the total series on intraoperative EEG monitoring despite a stump pressure of greater than 50 mm Hg. The degree of disagreement between stump pressure and EEG varied according to clinical category in this series. In those endarterectomies performed for completed stroke, all cases requiring shunting had stump pressures less than 50 mm Hg. In those cases performed for symptoms of vertebral basilar insufficiency, however, 77% of the cases requiring an intraoperative shunt had stump pressures greater than 50 mm Hg. A review of the complication rate in the various study groups indicates that the use of intraoperative EEG is a safe indicator of cerebral ischemia during carotid endarterectomy regardless of stump pressure.

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Task analysis of medical technology administration and supervision.

The purpose of this study was to develop a hierarchical set of administrative and supervisory competencies that a medical technology student should acquire before graduation from a medical technology program. The information that formed the basis for this research project was derived from responses to the Clinical Laboratory Supervision Survey completed by medical technologists, laboratory supervisors, administrative technologists, and education coordinators who are members of the American Society for Medical Technology. This paper presents the competencies that were identified as desirable from this task analysis study.

Administrative Personnel↗

Malignant superior vena cava obstruction: stent placement via the subclavian route.

Over a 3-year period 23 patients with malignant superior vena cava obstruction were referred for interventional management. They underwent repeat localized central venography and deployment of self-expanding Wallstents. All patients (age range 26-89 years) were approached by the subclavian route using 29 stents. The stent was used to exclude thrombus in the contralateral brachiocephalic vein in five patients and histologic information was available in all patients. Retrospective analysis of the clinical records was used to assess symptom-free survival and symptom recurrence. All patients reported an improvement in symptoms within 24 hr of the procedure. There was 100% technical success. Primary clinical success was achieved in 19 of 23 patients followed-up to their death with no symptom recurrence (range 1-34, mean 15 weeks). In four patients symptoms recurred but only one patient was referred for re-intervention, which was successful. Complications included single cases of early post-stent rethrombosis, distal slip on deployment, and distal slip on balloon dilatation. There were no puncture-related complications.

Adult↗

Alterations in brain function after loss of docosahexaenoate due to dietary restriction of n-3 fatty acids.

The concentration of the major polyunsaturated fatty acid (PUFA) in brain, docosahexaenoate, may be markedly reduced by two or more generations of dietary restriction of sources of n-3 fatty acids in the diet. Such a deficiency was induced through the feeding of safflower oil as the principal source of essential fatty acids. The reference point for this diet was an n-3 adequate diet to which alpha-linoleate and docosahexaenoate were added through the addition of a small quantity of flax seed or algael oils, respectively. The loss of brain DHA was associated with poorer performance in spatial tasks and an olfactory-cued reversal learning task. No difference could be observed in the hippocampal gross morphology. This study demonstrates the importance of providing a source of n-3 fatty acids during mammalian growth and development.

Animals↗

Comparison of colour Doppler ultrasound and digital subtraction angiography in the diagnosis of lower limb arterial disease.

A fifteen-month retrospective review (December 1993 to February 1995 inclusive) was performed comparing findings at Colour Doppler Ultrasound (CDU) and Digital Subtraction Angiography (DSA) in patients with symptomatic peripheral arterial disease or post-operative by-pass grafts. The records of 63 patients (43 males and 20 females) who had undergone both CDU and DSA within three months of each other were analysed. The age range of case studied was 33-84 years (mean 64 yrs.) Disease in each arterial or graft segment was classified into five grades, 0 (normal) to 4 (complete occlusion). A total of 72 limbs were examined. Fifty-four patients had unilateral symptoms while both limbs are affected in 9 cases. In all 241 arterial and graft segments were studied. There was overall agreement between findings of CDU and DSA in 193/241 (80/1%) and non-agreement in 48/241 (19.9%). Of the 48 examinations that showed discrepancy, the findings in 26/48 (54.2%) were one grade apart while in the remaining 22/48 (45.8%) there was a difference of two or more grades. Agreement between CDU and DSA in the individual arterial segments studied was as follows: common femoral 42/48 (87.5%); profunda femoris 19/25 (76.0%); superficial femoral 27/39 (81.0%); anterior tibial 17/81 (94.4%) and peroneal 15/17 (88/2%). In the grafts, there was an agreement of 20/27 (74/1%) between CDU and DSA. These results show a good correlation between the two imaging modalities with complete agreement and agreement within one grade in 80.1% and 90.9% of cases, respectively, confirming that CDU can be employed as a useful screening technique for assessment of symptomatic patients, allowing selection of patients for angioplasty alone or angiography for arterial mapping or those who require by-pass graft surgery.

Adult↗

The value of cardiac monitoring during peripheral arterial stress testing in the surgical management of peripheral vascular disease.

Eighty-six patients presenting with lower extremity pain on exertion underwent treadmill peripheral arterial stress testing with simultaneous cardiac monitoring. Of these patients 19 went on to have vascular reconstruction. Cardiac monitoring of peripheral arterial stress testing is a sensitive method of revealing occult cardiac disease in these high risk patients. It provides valuable information that can contribute to the surgical management of these patients. Specifically, ischemic exercise EKG patterns developed in 69.2% of patients with non-ischemic resting EKG patterns. Further, 80% of patients denying cardiopulmonary symptoms during peripheral arterial stress testing developed ischemic exercise EKG patterns. Of nine patients with significant ischemia on treadmill testing, two had vascular reconstruction postponed until after coronary artery bypass, four had extra-anatomic bypass. Two cardiac-related complications occurred, both in patients with ischemic exercise EKG patterns undergoing femoral-popliteal bypass.

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