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Biomedical subjects

J D Baker

Publications and source records attributed to J D Baker.

At least 145 records · Page 8Linked to original sources
PubMed1979

Pathogenesis of aortoduodenal fistula: experimental and clinical correlates.

An aortoduodenal fistula (ADF) is believed to stem from erosion of a rigid prosthesis into the fixed retroperitoneal duodenum. Experimental and clinical data do not support a mechanical etiology, but indicate that the pathogenesis is an unrecognized graft infection with pseudoaneurysm formation. A 5 cm segment of Dacron was interposed in the infrarenal aortas of 24 dogs that were divided into four groups of six animals each. In group 1 (control) the duodenum was fixed by sutures to the proximal anastomosis of the Dacron graft. At 6 weeks' follow-up, no ADFs or deaths had occurred among this group. In group 2 the duodenum was fixed to the aortoprosthetic anastomosis and the dogs received an intravenous infusion of 10(8) S. aureus; two of these dogs developed ADF (P less than 0.01). In group 3 the duodenum was incorporated as a patch on the anterior aspect of the aortoprosthetic suture line, creating a false aneurysm; three of these animals died as a result of ADF. A false aneurysm was created in group 4 dogs, as in group 3, but in addition, 10(8) S. aureus was administered intravenously; here five to six animals developed ADF. Clinical and bacteriological evidence of graft infection was present in seven of 11 patients with ADF who were seen over an 18 year period. Five had pseudoaneurysm formation at the proximal anastomosis. Operation was performed in eight patients; three had closure of the aortic leak and repair of the duodenum with omentum interposition. All resulted in recurrent fistula and delayed hemorrhage. Simple graft excision in two patients without reconstitution of peripheral circulation resulted in lower extremity gangrene. The three survivors had graft excision and axillofemoral bypass. These data suggest that the etiology of ADF is primary low-grade infection. Successful operation necessitates excision of the graft, duodenal closure, and an extraanatomical axillofemoral bypass graft.

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PubMed1979

Vertebral artery aneurysm: case report and review of the literature.

A nontender, nonpulsatile large anterior neck mass was found at operation to be an atherosclerotic aneurysm of the vertebral artery, an extremely rare condition. Proximal control and distal control were obtained and the aneurysm was excised. Aneurysms of the vertebral artery are infrequent but well-defined complications in connective tissue disorders such as the Ehlers-Danlos syndrome, and they can develop subsequent to penetrating neck trauma. However, no cases of atherosclertic vertebral artery aneurysms have been reported recently in the English-language literature. The case presented illustrates that this rare condition should be considered in all patients who have neck masses of undetermined etiology.

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PubMed1978

Pediatric intraocular knife.

An intraocular knife was developed that is of fine sharpness and small size to permit easy use in the eyes of young children.

Adult↗
PubMed1978

Poststress Doppler ankle pressures: a comparison of treadmill exercise with two other methods of induced hyperemia.

Postocclusion reactive hyperemia and isolated leg exercise were evaluated as techniques for functional evaluation of lower extremity arterial insufficiency by comparing them with treadmill exercise. Sixty patients with claudication and six normal subjects were evaluated. Changes in Doppler ankle pressures were measured after each form of stress. With substantial occlusive disease, there is a drop in pressure with gradual recovery. Postocclusion reactive hyperemia and isolated leg exercise are abnormal if the pressure does not return to resting levels within two minutes. There was good correlation between the three methods. Postocclusion reactive hyperemia avoids the problems of patient cooperation inherent in the other two methods. Postocclusion reactive hyperemia should probably replace treadmill exercise as the first method of stress testing lower extremities.

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PubMed1978

Position artifacts in occlusive impedance phlebography (plethysmography).

The accuracy of occlusive impedance phlebography (IPG) depends on recognition of the artifacts that produce false-positive results. Fifty per cent of a series of studies of patients with normal legs showed abnormal results when the recording was made with the leg held straight. We therefore recommend that the patient's leg position be carefully monitored when an IPG test is being administered.

Diagnostic Errors↗
PubMed1978

Evaluation of extracranial cerebrovascular disease with ocular pneumoplethysmography.

The results of OPG studies performed on 121 patients between 1974 and 1977 are compared with the results of biplane angiograms. By adding criteria based on the ratio of AOP:BAP, the overall accuracy was increased from 76.9 to 91.7 per cent. This improvement was obtained by establishing criteria that identified bilateral significant lesions. The results have confirmed the value of OPG in noninvasive assessment of carotid artery disease.

Air↗
PubMed1978

Infrarenal aortic occlusion.

Twenty-eight patients with total occlusion of the infrarenal aorta have been seen at the UCLA Hospitals in the past 11 years. Claudication was the presenting complaint in all but one patient, with one-third having ischemic rest pain. The average age of these patients was 54 years, and their histories revealed a surprising absence of myocardial infarction, stroke, or diabetes, although 40% had essential hypertension. Heavy tobacco use, however, was characteristic of the entire group. Arteriography proved valuable in identifying and characterizing the vascular abnormalities, but posed problems in technique and interpretation. Significant distal arterial disease was detected radiographically in only 21% of these patients. Operative correction of the aortic occlusion was performed on 26 patients, 18 by aortic bypass grafts and eight by aorto-iliac endarterectomy, with one early postoperative death. Although the thrombus extended to the renal artery origins in 77% of the cases, a well-designed technical approach did not require renal artery occlusion. Using serial creatinine determinations, one case of renal insufficiency was detected which was associated with prolonged postoperative hypotension. Although the extent of distal disease was more severe in those who underwent bypass, symptoms of claudication returned earlier and were more prominent in the endarterectomy group. This recurrence of systems was not favorably altered by sympathectomy performed concomitantly with the initial procedure. Even though this condition seems to pose difficult technical obstacles and has a poor prognosis, infrarenal aortic occlusion can be successfully treated by aortic bypass, with favorable long-term results, if particular attention is paid to elements of the preoperative evaluation and the intraoperative technical requirements peculiar to this relatively uncommon disease entity.

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PubMed1975

An evaluation of electroencephalographic monitoring for carotid study.

Continuous electroencephalogram (EEG) monitoring was used during 213 carotid endarterectomies in 157 patients to identify cerebral ischemia. General anesthesia was used for all patients. An intraluminal shunt was not used routinely, but was inserted in 23 operations when EEG abnormalities associated with ischemia appeared. EEG changes occurred in 31 operations (14.5 percent). Four patterns of abnormal recordings were identified and are discussed. Six patients developed ischemic EEG changes in association with hypotension during endarterectomy. In two of these patients changes appeared with a blood pressure drop of only 20 mm. Hg below preoperative levels. Four patients with internal carotid artery back pressures of 75 to 100 mm. Hg developed EEG abnormalities which disappeared after shunt insertion. Our experience emphasizes the value of continuous EEG monitoring in detecting inadequate cerebral perfusion.

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