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Biomedical subjects

E W Pollak

Publications and source records attributed to E W Pollak.

51 records · Page 3Linked to original sources
PubMed1977

Arterial scan versus radiographic angiography in detection of shallow arterial ulcers.

A comparison of 99m-technetium albumin aggregated arterial scan and radiographic angiography for detection of shallow intimal carotid artery ulcerations was made in a series of 12 anesthetized dogs, having a total of 16 acute arterial ulcerations. Radiographic angiography showed positive findings related to presence of stenosis or mural thrombosis in 12 instances. Direct visualization of ulceration was only exceptionally encountered. Arterial scan detected 14 of 16 intimal ulcers. The radionuclide method was reliable even in absence of stenosis or when only minimal mural thrombosis was present. Moreover, autopsy scan of the isolated arterial segments detected all 16 intimal lesions. These results indicate that the arterial scan was a more reliable method for detection of shallow arterial ulcers in this experimental model than radiographic angiography, especially when arterial lumen stenosis or mural thrombosis were minimal or absent.

Angiography↗
PubMed1977

Abdominoperineal resection in the treatment of devascularizing rectal injuries.

Local debridement, drainage, and diverting colostomy, with or without primary repair of the rectum, have been considered to be the standard treatment for most rectal injuries, but they are not sufficient for those patients sustaining uncontrollable bleeding or extensive rectal devascularization. This report assessed the indications and results of abdominoperineal resection of the rectum in these patients. Ten patients who were victims of explosive trauma presented with massive perineal injuries and extensive rectal devascularization. Six of these were treated with local debridement of necrotic tissue, pararectal drainage, antibiotics, and colostomy. Five of the six patients initially treated by colostomy died after operation from hemorrhage or sepsis. The sixth patients, who survived, had an abdominal resection of the rectum performed 5 days after the colostomy for removal of a gangrenous rectum. All five of those who underwent abdominoperineal resection survived (p less than 0.01). Increasing violence in the life patterns of modern society enhances the possibility of occurrence of this type of lesion, previously limited to military practice. The need for careful investigation of rectal viability is emphasized. Primary abdominoperineal resection of the rectum is advised when extensive devascularization has occurred.

Abdomen↗
PubMed1975

Radioisotope detection of venous thrombosis. Venous scan vs fibrinogen uptake test.

Experience with the fibrinogen uptake test and the technetium Tc 99m albumin aggregated venous scan in 89 patients showed the latter to be adequate for simultaneous screening for plumonary embolism and venous thrombosis of the lower extremities and pelvis. Because the fibrinogen uptake test differentiated active from inactive venous thrombosis, it is indicated when anticoagulation is considered for patients with a history of thrombophlebitis and equivocal clinical findings of acute activity. It can also be used to monitor high-risk patients and to detect proximal propagation of thrombi. The results of the technetium venous scan were abnormal in 97% of patients with venous thrombosis and the fibrinogen uptake test detected 100% of patients with acute activity. Both tests react to different aspects of the thrombotic disease, thus complementing each other. Because of their reliability, indications for phlebography are now less frequent.

Albumins↗
PubMed1975

Adult respiratory distress syndrome in postoperative patients: study of pulmonary pathology in "shock lung" with prophylactic and therapeutic implications.

Lungs of 44 patients who died after postoperative respiratory distress and shock had a significantly higher incidence of atelectasis and thromboembolism than did 31 control patients. However, both lesions were as inconstant in occurrence as all other 15 investigated pulmonary changes. Moreover, no clear correlation between lung pathology and duration of shock was found and the incidence of thromboembolism was too low (one clot for each 16 or more counted vessels) to generate any significant vascular obstruction. Furthermore, pulmonary pathology in patients with postoperative respiratory distress was independent of the presence or absence of shock and some of the most typical findings of "shock lung" were more often present in patients who did not have shock but died of aspiration pneumonia. While possibly a contributing factor, shock is not the most important cause of the pulmonary lesions in postoperative patients. The term "shock lung" should be eliminated and renewed emphasis should be placed on detection, prevention and treatment of the pathogenic mechanisms involved in each individual case.

Lung↗
PubMedDate not supplied

Mural thrombosis after experimental carotid endarterectomy.

The incidence of mural thrombosis following three types of experimental intimal injuries at common carotid arteries, was investigated in a series of 12 dogs. Mural thrombosis was obtained at each of the intimal lesions. Moreover, obstructive thrombosis occurred in three instances. Further investigation of thrombi revealed that partial fragmentation occurred when exposed to hydrodynamic forces. These results suggest that mural thrombosis following carotid endarterectomy in humans, is possibly more frequent and significant than it is generally appreciated, thus leading to the consideration of postoperative anticoagulation after endarterectomy, as a means to minimize the incidence of postoperative embolic cerebrovascular accidents.

Animals↗
PubMedDate not supplied

The effect of postural changes upon the ankle arterial perfusion pressure.

The normal arterial blood pressure at the ankle, (AP), right brachial arterial pressure (RBP) and pressure index (PI) were investigated in 50 healthy young volunteers under basal conditions and during certain positions of the legs, utilizing Doppler ultrasound flow determination and standard size blood pressure cuff. The mean AP was 10 mm Hg higher than the mean RBP in 76 instances but AP was smaller than RBP in 24 out of 100 investigated lower extremities. Mean PI was 1.069+/-0.158. There was no statistically significant difference between PI of heavier and leaner patients although increased weight was associated with a significantly higher brachial and ankle arterial pressure. Departure of the lower extremity from the horizontal position resulted in AP changes explained by gravitational effects. If the new posture was maintained, the new AP persisted, thus indicating an absence of significant corrective circulatory adaptation to the posture changes. Extreme flexion of hip and knee joints resulted in a marked decrease of AP and PI, suggesting arterial kinking. This change was not affected by the weight:height ratio of the subject. It is concluded, therefore, that the presence of a greater amount of periarterial soft tissues does not significantly prevent arterial kinking. These tensional shifts indicate changes of flow pattern occurring in normal subjects during extreme flexion. Even more marked shifts can be anticipated in arteriosclerotic patients under similar circumstances.

Adult↗
PubMedDate not supplied

The choice of test for diagnosis of venous thrombosis.

Doppler ultrasound is the preferred screening test in asymptomatic patients with high risk for venous thrombosis. Radiographic phlebography leads to definitive diagnosis in most instances. Radionuclide angiography using 99mTc MAA with delayed images to detect particle entrapment in venous blood clots can be used when radiographic phlebography is contraindicated or impractical. To detect active thrombosis in patients with past venous disease, the serial fibrinogen uptake test is the method of choice. This method is also used to monitor the efficacy of anticoagulation therapy and to detect propagating thrombosis in patients failing to respond to anticoagulation, hopefully before massive lethal pulmonary embolism occurs. Radionuclide methods are contraindicated in pregnant women and children where non invasive methods are preferred. No completely satisfactory test exists for detection of hypogastric vein thrombosis. Among the methods currently being evaluated in the laboratory the ultrasound B-scan imaging, 99mTc MAA uptake test and 99mTc mAA venous scan offer the best possibilities for successful clinical application.

Drug Hypersensitivity↗
PubMedDate not supplied

Early diagnosis of anticoagulation failure: can recurrent pulmonary embolism be prevented?

Propagating thrombosis, occurring in spite of full anticoagulation, is an early indication of the failure of anticoagulation therapy. Its detection can be successfully accomplished by routinely monitoring all heparinized patients with serial fibrinogen uptake tests or serial Doppler ultrasound venous flow evaluation in selected lower extremity veins. If anticoagulation therapy failure is detected, it should be corrected immediately. In already fully anticoagulated patients who nevertheless develop propagating thrombosis, inferior vena cava interruption should be performed before potentially lethal pulmonary embolism occurs.

Fibrinogen↗
PubMedDate not supplied

Sodium nitroprusside pharmacoangiography: arteriographic enhancement by local vasodilation.

Sodium nitroprusside (SNP) was injected intra-arterially into the right femoral artery of five dogs, to promote arteriographic enhancement with minimal systemic effects. Injection of 3 microgram/Kg SNP or more, produced tachycardia, hypotension and increased pulsatile arterial blood flow. a 36% pulsatile arterial flow increase, which lasted 25 seconds or less, was the most remarkable systemic change seen after intra-arterial injection of 2.5 microgram/Kg SNP. Small doses were followed by even lesser systemic changes but were ineffective in promoting arteriographic enhancement. Comparison of arteriograms obtained before and after 2.5 microgram/Kg SNP injection showed increased arterial diameter, greater architectural detail and extensive visualization of previously undetected smaller arteries in post-SNP angiograms. Thus, suggesting that 2.5 microgram/Kg was the optimal SNP dose for production of local arterial without remarkable systemic effects. Good results of SNP pharmacoangiography in this experimental series suggest that further research on this topic is warranted.

Angiography↗