Biomedical subjects
Publications and source records attributed to T Winsor.
A series of noninvasive vascular tests was performed on groups of normal individuals (Group I) and on patients with chronic deep vein thrombophlebitis (Group II) to determine the relative specificity and sensitivity of the tests. Results indicate that the simpler tests, requiring a minimum of equipment and technique are as effective as certain of the more sophisticated procedures.
A new computerized plethysmograph allows segments of the vascular system to be examined accurately and automatically. Laser flowmetry allows blood flow measurements to be made of digital circulation for vascular abnormalities. With the 2 new instruments, large and small vessel circulations can be measured quickly and easily. Disease of these vessels can be readily detected. Thus, appropriate medical or surgical therapy can be investigated.
The purpose of this study was to determine a standard set of conditions for detecting peripheral arteriosclerosis with ischemia. One series of studies was done to determine the influence of room temperature on peripheral flow in healthy subjects and patients with peripheral vascular disease. The room temperature was varied from 30 degrees to 35 degrees C. The temperature from 24 degrees to 30 degrees C had only minor effects on the circulation. Thus, it seemed appropriate to use a room temperature in the lower range, usually 23 degrees C. Another series of studies showed the effect of changing skin temperatures locally at the finger tip or toe tip on the plantar and volar surfaces in healthy subjects and in patients with peripheral vascular disease. Results showed that as temperature was increased from 10 degrees to 45 degrees, there was a marked increase in the finger and toe circulations, which was considerably greater in the normal subjects as compared with those with digital disease. The ideal temperature at which to work as a routine is 40 degrees C as opposed to the lower temperatures, which did not separate healthy subjects from patients with peripheral vascular disease. A third experiment was done to study normal subjects and patients by using the finger circulation as control against the toe circulation when the conditions were a local skin temperature of 40 degrees C and a room temperature of 23 degrees C. A toe-finger index was established to detect abnormalities in the circulation.(ABSTRACT TRUNCATED AT 250 WORDS)
The thoracic outlet syndromes of the upper extremities consist of many disorders. The most important two are the costoclavicular syndrome (compression of neurovascular structures between the clavicle and the first rib) and the scalenus anticus syndrome (compression of these structures within the scalene triangle). Congenital abnormalities of the clavicle, congenital small thoracic outlet, high first rib, cervical ribs of all configurations, pectoralis minor and pectoralis major syndromes, and others may occur. The costoclavicular syndrome and scalenus anticus syndrome have been considered the most prevalent compression syndromes and are amenable to surgical or medical treatment. Quantitative measurements of the microcirculation of the fingertip were examined with the shoulders and head in various positions to provide quantitative information relative to the costoclavicular and scalenus anticus syndromes. A laser instrument was ideal for this purpose, for results were quantitative and no counterpressure was applied during the measurement. The technic applied was highly successful in separating quantitatively the normal individuals from those with either costoclavicular syndrome or scalenus anticus syndrome.
A short historical note on plethysmography is given and the development of the modern computerized pneumoplethysmograph is described. The computer-aided pneumoplethysmogram (CAP), with proper programming, makes possible numerous computations that give new, useful, and rapid information about the patient. New applications of the CAP will quickly develop and the data collected will be quickly analyzed and displayed.
The cutaneous laser Doppler device (LDF) was employed to determine its usefulness in differentiating the circulation of the feet in normal subjects from that in patients with arteriosclerosis obliterans. It is shown that the laser Doppler frequencies correlated well with results from venous occlusion plethysmography, which measured volume rate of flow. Thus, one can determine volume rate of flow by the simple Doppler method. There was a linear relationship between these two methods of measurements. Using the LDF method, it was determined that normal individuals have toe flows that on the average are 42% of finger flows in supine resting subjects. In peripheral vascular disease of the lower extremities, the LDF measurements showed a decreased circulation in the large toes when the patients are supine and the lower extremities flat. The results between health and disease are exaggerated by elevating the feet, at which time the diseased circulation falls to extremely low values compared with those of normal subjects. A similar decrease in skin oxygen tension in the diseased lower extremities was observed when the limbs were elevated.
The availability of a relatively small computer with programming providing multiple-gated acquisition capability (MUGA) permits the measurement of ejection fraction and evaluation of ventricular wall motion without the need for invasive techniques. It is probable that the various nitrates available--nitroglycerin, PETN, and isosorbide dinitrate--have somewhat different hemodynamic effects, and that the radionuclide technique can assist in determining these differences and may help to predict which agents might be most appropriate in specific situations.
This systems approach to the diagnosis of venous vascular obstruction and venous insufficiency relies on use of the segmental pneumoplethysmograph. The method is a useful diagnostic tool when evaluating these diseases. The drainage test indicates deep, large venous thrombosis. The dependency test indicates either thrombosis or venous insufficiency. And the tourniquet test differentiates the presence of deep from superficial vein insufficiency.
A thorough search for the natural history of arteriosclerosis involving the cerebrum, aorta, and peripheral vessels has been made. The disease's rate of progress has been studied anatomically, clinically, radiologically, and plethysmographically. We conclude that arteriosclerosis is usually associated with other diseases such as diabetes, high blood cholesterol, and hypertension. Heart disease in particular is often the cause of the patient's death, rather than the peripheral arteriosclerotic disease itself. The usually slow development and course of arteriosclerosis indicate that its treatment is largely a medical problem. It seems important to control the various risk factors and to utilize surgical therapy to attack specific lesions which threaten the tissues. A thorough cardiovascular profile of the patient should be compiled and should include a glucose tolerance test and lipoprotein phenotyping.
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With the use of a three-phase experimental design, the efficacy of oral nitroglycerin has been evaluated in a total of 53 patients with documented angina pectoris due to coronary artery disease. The study were a double-blind, randomized, and cross-over comparison of controlled-release nitroglycerin (2.6 mg. tablets administered three times daily) and an indistinguishable placebo. Sixteen patients recorded anginal symptoms by the diary method over a 6 month trial of randomly sequenced 1 month periods of drug or placebo. In 15 patients, ST segments were monitored with a Holter dynamic electrocardiograph for periods of 10 to 12 hours under normal life style and evaluated by matching activities during periods of drug and placebo. In 22 patients, a multistage treadmill exercise test was conducted to an endpoint of anginal pain. The three phases of the investigation were run in succession; each phase was completed before the next one was begun. Oral nitroglycerin reduced the incidence and severity of anginal attacks by 47.2 and 49.4 per cent, respectively, and decreased the number of sublingual nitroglycerin tablets used by 51.1 per cent in comparison to placebo (p less than 0.001). Eleven of 16 patients (69 per cent) decreased their need for sublingual nitroglycerin by over 50 per cent. Based on a polynomial trend analysis over a period of 8 weeks, no tolerance to the therapeutic effects of the drug was found. With DCG monitoring, drug decreased the ST segment depression from 1.76 mm. on placebo to 1.12 mm, with a significant difference of 0.64 mm. (p less than 0.001). ST segment depression was decreased more than 0.5 mm. by drug in comparison to placebo in 10 of 15 patients (66 per cent). Larger depressions of the ST segment noted with placebo at heart rates greater than 80 beats per minute were prevented by administration of the drug. During treadmill exercise, drug delayed the onset of pain by 83 seconds (64 per cent) over placebo (p less than 0.001) and decreased the duration of pain by 70 seconds (49 per cent) in comparison to placebo (p less than 0.001). Drug did not affect heart rate or systolic blood pressure at rest or after exercise, as well as rate-pressure product for production of angina following exercise (p less than 0.05). There was no side effects reported caused by the drug. The data demonstrate that oral nitroglycerin, given as controlled-release tablets, was absorbed from the gastrointestinal tract in quantities sufficient to provide statistically significant clinical improvement of angina pectoris.
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A short historical development of pneumoplethysmography and its clinical usefulness has been given and the older instruments have been compared with a modern computerized pneumoplethysmograph. The computer aided plethysmogram, with proper programming, makes possible numerous computations which give new and useful information about the circulation. New applications of the CAP will quickly develop and the data collected will be only limited by the imagination.