In this study, eighty limbs (71 patients) with clinically suspected deep venous thrombosis (DVT) were investigated by both venography and Doppler ultrasonography. Diagnosis was confirmed by venography in 67 limbs and Doppler ultrasonography was positive in 66 of them with the Doppler sensitivity of 98%. In the remaining 13 limbs clinically suspected to have DVT, neither venography nor Doppler ultrasonography found any abnormality in the venous system of the lower limbs.

A prospective study of 6,527 hospitalized patients was performed to evaluate the effectiveness of multivariate analysis of risk factors to correctly designate risk for pulmonary embolism. History of previous pulmonary embolism was the single most important factor. In patients without prior history, five factors emerged: inactivity, congestive heart failure, Doppler ultrasound evidence of deep-vein occlusion, female sex, and black race. Used together, these factors permitted a discrimination of risk such that 68.7% of pulmonary embolization was found to occur in 32.2% of the population designated as showing increased risk. Multivariate analysis of clinical factors improved assessment of risk, compared to the use of lower extremity findings alone, and proved to be useful in identifying individuals at increased risk for pulmonary embolism.

Pulsed Doppler ultrasound blood flow detection has been used in a noninvasive manner to detect arterial abnormalities associated with arteriosclerosis. Sound spectrograms of ultrasound signals obtained from in uitro and animal studies in which flow was disturbed by obstacles placed in the flow stream showed a different distribution of energy over frequency than signals obtained from studies with no flow disturbances. Similar findings were seen clinically. A technique has been developed which can detect disturbed flow patterns resulting from partial occlusion in important superficial arteries (e.g. femoral and carotid) up to 15 cm distal to localized arterial wall abnormalities. Thirty‐five arterial examinations of normal and arteriographically abnormal arteries in 12 patients revealed a sensitivity of 83 percent and a specificity of 61 percent. This study suggests that pulsed Doppler ultrasound may be useful as a screening technique for detection of arteriosclerotic lesions in major superficial arteries.

Determination of the optimal compression to reduce venous stasis was studied in terms of the amount of pressure and manner of application (graded or uniform pressure). Both lower extremities of seven inactive recumbent subjects were tested using transcutaneous Doppler ultrasonic measurement of femoral vein blood flow velocity. Optimal compression was defined as the externally applied pressure that produced the greatest increase in femoral vein flow velocity consistent with safety and the practicality of hospital use of elastic stockings. Optimal compression for elastic stockings to be used by hospitalized patients who spend substantial time in bed should be 18 to 8 mm Hg (ankle to midthigh). At this compression, average femoral vein blood flow velocity is increased to 138.4% of base line. Gradient compression at this level was found to produce a greater femoral vein flow velocity than the same amount of compression distributed uniformly over the lower extremity.

SICEL, BERNARD M.D.; IPSEN, JOHANNES M.D.; FELIX, W. ROBERT JR. M.D. Author Information

Blood flow velocity was measured in the femoral veins of ten inactive recumbent subjects in order to determine the effect of elastic stocking compression on venous flow. A noninvasive Doppler ultrasound technique was used to measure blood flow velocity. Results of these studies indicate that elastic stockings increase femoral venous flow velocity during periods of compression up to three hours. This increase in blood flow velocity persists for up to 30 minutes after removal of stockings. Compression reduces the fluctuation effect of respirations on venous flow, resulting in a more constant flow. These findings indicate that elastic compression of the lower extremities produces effects (increased venous flow velocity and decreased venous pooling) that may reduce the occurrence of venous thrombosis.

Since December 1968, we have been conducting a prospective study of the prevalence and incidence of venous disease in hospitalized surgical patients. A combined clinical and Doppler ultrasound examination has been performed at the patient's bedside. This report will present a brief description of the technique, an estimate of the accuracy of clinical ultrasound examination and the initial prevalence and incidence findings in patients undergoing elective operation at The Medical College of Pennsylvania and the Philadelphia Veterans Administration Hospitals. The objectives of the prevalence and incidence study that is in progress is to determine the following information obtained by clinical and ultrasound examination about lower extremity venous disease in surgical patients:

In a previous publication, we described a Doppler ultrasound method for diagnosing venous disease of the lower extremities. 1 This technique is used to detect occlusion of deep veins due to thrombosis and incompetent valves associated with the postphlebitic syndrome. The preliminary results in 72 patients with confirmed diagnoses indicated that the ultrasound method was significantly more precise than clinical appraisal alone in the diagnosis of thrombotic occlusion of deep veins of the lower extremities. 2 We have expanded this series by adding 75 more patients in whom confirmation of Doppler ultrasound findings was obtained usually by venography and occasionally by operation or autopsy. As our experience has increased, we have simplified the examination for occlusion by deleting certain maneuvers which were found to be redundant. This has enabled us to evolve a more systematic and specific set of criteria for abnormality on the ultrasound examination. Furthermore, the additional clinical

Sigel, Bernard MD; Popky, George L. MD; Boland, James P. MD; Wagner, David K. MD; Esmond, McD, Mapp, MD Author Information

THE MEASUREMENT of hepatic circulation has presented multiple problems both in investigative and clinical application. Two approaches have been usually employed. One method has been to administer a substance which is selectively removed by the liver from the blood stream and then to estimate blood flow on the basis of its hepatic pickup or blood clearance. The other method has been to measure blood flow in the hepatic vessels per se. The first technique presumes functional integrity of the tissue in order to remove the blood borne indicator. The second approach necessitates the dissection and isolation of hepatic blood vessels (with or without cannulation). Another means to evaluate liver circulation without dependence on functional integrity or isolation of blood vessels would be to measure the clearance or "drainage" of material injected directly into the liver tissue. Kety1has demonstrated that the clearance of a radioisotope from a tissue is

Partial hepatectomy has served as a valuable experimental tool with which to study liver regeneration and function. The presence of rather complete fissures between the hepatic lobes of laboratory animals has greatly facilitated resection and has provided a means of estimating the amount of tissue which has been removed. The techniques of partial excision in the rat2and the dog1are well standardized. Both methods are designed to resect about two-thirds of the liver and consist of ligating the base of the lobes to be removed with amputation of liver tissue distal to the ligature. Although this procedure is simple and rapid, it is associated with a high mortality where other surgical maneuvers are needed concomitantly (eg, partial hepatectomy and Eck fistula in dogs). This situation could be due to 1) excessive trauma of operation associated with retention of devitalized liver tissue, 2) production of a severe physiologic