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At least 541 records · Page 30Linked to original sources
PubMed1985

Measurement of limb blood flow by electrical impedance plethysmography.

Limb blood flow has been measured in 72 individuals by the noninvasive technique of electrical impedance plethysmography. Venous occlusion was not used. Blood flow was measured in 230 limbs in which 195 limbs were either in normal individuals or the clinically normal limbs of patients (normal limbs). Thirty-five limbs were clinically abnormal. Measurements on limbs with clinical abnormalities showed that blood flow values often fell within the limits of the normal range. However 3 cases of known vascular injury and 2 cases studied after hand surgery under tourniquet showed lowered blood flow values by comparison with the unaffected limb. A simultaneously recorded range of cardiac output and stroke volume measurements gave similar results to those obtained in a previous, unconnected study.

Adolescent↗
PubMed1985

[Measurements of respiratory resistance in tracheal stenosis patients. A comparison of pressure changes with total-body plethysmography].

In this study, the airway resistance of 67 patients who suffered tracheal stenosis was measured by body plethysmography and by the pressure change method. These comparative measurements were carried out in order to assess the value of the pressure change method. There was significant linear correlation between the results for the two methods. The pressure change method is uncomplicated and mobile, and promises to have many practical applications.

Adolescent↗
PubMedDate not supplied

Respiratory inductance plethysmography: calibration techniques, their validation and the effects of posture.

Respiratory inductance plethysmography (RIP) is used to measure ventilation from two measurements of body surface movements (rib-cage and abdomen) via the application of volume-motion (V-M) coefficients. The correct derivation of both V-M coefficients (calibration) is necessary because there are considerable spontaneous variations in relative contributions from these two compartments even during resting breathing. In order to fully test a calibration, deliberate changes in rib-cage (RC) to abdominal (AB) contribution must be made. We used this approach to test two single-posture calibration techniques, multiple linear regression (MLR) and isovolume (ISV). Ten normal subjects and nine patients with chronic airway obstruction (CAWO) were studied using quiet breathing throughout. We also studied the effects of changing posture on the constancy of the V-M coefficients. MLR proved a little more accurate (p = 0.03) in deriving the V-M coefficients than ISV in normal subjects, and ISV consistently underestimated the AB V-M coefficient relative to RC. No difference between the two techniques existed in patients with CAWO. Both MLR and ISV calibrations failed to give acceptable calibrations in some patients. When MLR calibration was used, a deliberate 20% change in relative compartmental contribution (RC-AB) induced mean errors in RIP estimations of tidal volume of 3.5 and 9.5% in normal subjects and patients respectively. When there were no deliberate changes in relative contribution, the 95% confidence limits of individual tidal volume estimates were +/- 6.6 and +/- 12% in normal subjects and patients respectively. MLR calibration provides a statistical estimate of its quality at the time of V-M coefficient derivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Peripheral circulation in hypertensive patients: findings by digital pulse plethysmography.

Sixty one non diabetic, asymptomatic patients with untreated primary hypertension and 122 age and sex matched non diabetic controls have been investigated in the peripheral circulation of the lower limbs by digital pulse plethysmography. The inclination time of the ascending ramp has been chosen as index of arterial wall elasticity. Inclination time was prolonged in the hypertensive group as compared to the control one (123 +/- 29 vs 107 +/- 13 msec; p less than .001). In addition, by using a cut-off point of 120 msec (X +/- 1SD of controls) 23/61 hypertensives and 26/122 controls presented an inclination time above this value (p less than .05 by chi square test). Since no other difference was observed in the main cardiovascular risk factors, we conclude that high blood pressure may produce early structural lesions of the vessel wall.

Adult↗
PubMedDate not supplied

[Measurement of the effects of Barbotan-les-Thermes waters on the venous filling and drainage in patients with phlebitis and varicosities using plethysmography with a measuring gauge].

The effects of Barbotan waters have been tested using plethysmography with a mercury gauge, with venous occlusion in 73 patients taking the cure with venous pathology; 43 legs with phlebitic sequelae, 72 varicose legs. The principal parameters of filling and emptying were measured. Dynamic pictures made it possible to show the variation in these parameters. The publication demonstrates a remarkable normalization effect in the venous functions. In it we discuss classification by the plethysmographic means alone and the eventuality of the venous areas. We conclude by linking this normalising effect on the venous functions with the antispasmodic effect already discussed in an earlier work.

Balneology↗
PubMed1985

Digital pulse plethysmography--a tool for investigating vasoactive substances.

Plethysmographic investigations have been in use for at least a hundred years for the measurement of pharmacological actions in humans. Finger plethysmography was used particularly in the investigation of the vasodilating effect of organic nitrates. It has also proved valuable in determining the relative bioavailability of representatives of this class of drugs. This paper deals with personal experience in the use of this method for the investigation of older and newer organic nitrates. The apparatus that was developed to enable electronic data processing of the plethysmographic signals is described. The effects of other pharmacological interventions on finger volume pulse are also discussed, and the finger plethysmographic investigation of vasodilating substances that belong to classes of drugs other than organic nitrates is presented. The possibilities and limits of the method are discussed.

Carbazoles↗
PubMed1985

[Circulatory values of the upper extremity--results using venous occlusion plethysmography in normotensive persons with healthy vessels and hypertensive patients].

In 386 test persons with healthy vessels of different age indices of the blood supply of the upper extremities were established by means of the plethysmography of plebembraxis. While with regard to sex, side of the examination and behaviour of the blood pressure no essential differences are existing, there is a distinct age-dependence of the results which must be taken into consideration when the norm-value is established.

Adolescent↗
PubMed1979

[Automated body plethysmography of respiration and voice efficiency (author's transl)].

Efficiency of voice (EV) is understood as the ratio of gained acoustic power to respiratory power during phonation. A fully automatic computer programmed to calculate the EV and the subglottic pressures via body plethysmography is described. The EV ranges from 0.5 x 10(-5) to 120 x 10(-5). The relationship between EV and sound pressure is demonstrated. The results were reproducable.

Automation↗
PubMedDate not supplied

Plethysmography during aorto-iliac surgery.

Cardiac output, arterial and central venous pressures and calf blood flow were used to monitor patients undergoing abdominal aortic surgery. Measurement of calf blood flow by means of venous occlusion plethysmography showed that measurable blood flow to the legs persisted after clamping of the aorta in patients with occlusive aortoiliac lesions and that the hyperaemic response following release of the clamp was reduced. Arterial hypotension after clamp release was of the same time course as the hyperaemia. Leg blood flow measurement was a valuable monitoring procedure.

Aged↗
PubMed1979

A prospective study of Doppler pressures and segmental plethysmography before and following aortofemoral bypass. Implications for predicting success and for adopting a uniform method of classifying arterial disease.

To determine the clinical and hemodynamic changes associated with aortofemoral bypass, 44 limbs of 31 patients underwent segmental plethysmography (PVR) and Doppler pressures (DSP) before operation, immediately after operation, and again at 6 months. Prior to operation patients were separated by angiographic criteria into two groups: aortoiliac segment disease alone (AI) (n = 22), and aortoiliac and femoropopliteal segment disease (AIFP) (n = 22). At 6 months the two groups were subdivided into four groups based on relief (oSx) or lack of relief (+Sx) of symptoms. Before operation the only significant difference between the four groups was a higher thigh PVR and calf DSP in the AI + Sx group. Six month PVR values in AIoSx were improved nearly twofold over preoperative measurements at the thigh and calf, but at the thigh level only for AIFPxSx. DSP was increased at all three levels in both AI and AIFPoSx groups. No hemodynamic improvement occurred in either the AI or the AIFP + Sx groups. A derivative index of PVR (thigh-ankle/15 mm) or the FPomega was significantly lower in AIFOsSx before operation. There was a significant disparity between classification by hemodynamics and by symptoms prior to operation which lessened somewhat after operation. These studies suggest that success or failure can be predicted before operation in AIFP by FPomega, and arterial disease should be classified by a combination of symptoms, angiography, and hemodynamics.

Angiography↗
PubMed1979

Deep vein thrombosis following aortic surgery: prospective evaluation of I125 fibrinogen and impedance plethysmography.

A prospective comparison of I125 Fibrinogen uptake testing (FUT) and Impedance Plethysmography (IPG) was made in 22 patients (44 limbs) following aortic reconstructive surgery to determine the incidence of postoperative deep venous thrombosis (DVT). Normal FUT was obtained in 34 limbs, whereas ten limbs had abnormal uptake over the calf area consistent with venous thrombosis. Nine of the ten limbs with a positive scan underwent phlebography. All venograms and IPG readings obtained were normal. No evidence of DVT following aortic surgery was noted in this study. A high incidence of false positive FUT was evident. IPG is noninvasive, reliable and relatively inexpensive and is therefore recommended if prospective evaluation for DVT in patients undergoing aortic surgery is desired.

Adult↗
PubMed1979

[Raynaud's syndrome: study of fingertip blood flow by plethysmography with venous occlusion (author's transl)].

The fingertip blood flow was measured by venous occlusion plethysmography in a room at 22 degrees C, in 52 patients with Raynaud's syndrome and 24 healthy controls. In severe Raynaud's syndroms (24 cases incuding: scleroderma: 7 cases, thromboangitis: 5 cases, disabling syndrom without known etiology: 12 cases), the flow was significantly lower than in moderate Raynaud's syndroms (19 cases including 10 primary and 9 secondary syndroms) i.d. 7.5 +/- 7.3 ml versus 25 +/- 15 ml (p < 0.001). Controls had significantly higher flow (35 +/- 12.3 ml) than moderate Raynaud's syndroms (p < 0.05). Raynaud's syndroms with permanent acrocyanosis had a low flow (8.7 +/- 5.3 ml) not different from severe syndroms.

Adolescent↗
PubMed1978

Occlusive impedance plethysmography. A noninvasive method of diagnosis of proximal deep vein thrombosis.

The purpose of this study was to assess and confirm the accuracy of impedance plethysmography (IPG) by the occlusive cuff method, in detecting proximal (popliteal, femoral and iliac) deep vein thrombosis in patients with symptomatic limbs. In 27 patients 30 consecutive limbs were studied with concurrent venography and IPG. The IPG result was normal in 9 of 9 limbs which were normal on venography, and abnormal in 15 of 16 limbs which showed venographic evidence of proximal deep vein thrombosis (DVT). An abnormal IPG strongly suggests proximal DVT (predictive value 0.88). A normal IPG virtually rules out proximal DVT (predictive value 1.0).

Adult↗
PubMed1977

Clinically suspected deep venous thrombosis of the lower extremities. A comparison of venography, impedance plethysmography, and radiolabeled fibrinogen.

To define the utility of new diagnostic approaches in patients with clinically suspected deep venous thrombosis of the lower extremities, 42 legs of 33 patients were studied by fibrinogen labeled with radioactivie iodine (125I) impedance plethysmography (IPG), and contrast venography. The clinical diagnosis was confirmed in approximately two thirds of the legs and patients. In venogram-positive legs, fibrinogen 125I was positive in 70%, IPG in 61%, and one of the two in 78%. In venogram-negative legs, fibrinogen 125I was positive in four (21%) and IPG was negative in all. It was found that the size, age, and location of the thrombus, collateral vein development, heparin sodium therapy, and technical-interpretive choices can influence both IPG and fibrinogen 125I results. The data demonstrate that the fibrinogen 125I and IPG procedures can assist physicians in the diagnosis of clinically suspected deep venous thrombosis of the lower extremities.

False Negative Reactions↗
PubMed1977

The effect of inactivity on reactive hyperaemia in the human calf: a study with strain gauge plethysmography.

In order to study the influence of muscular inactivity on reactive hyperaemia, postischaemic blood flow was measued with strain gauge plethysmography in the calf of twenty-nine patients, who had been treated with a plaster cast for a trauma of the lower limb. The contralateral leg served as a comparison. In all but two patients postischaemic maximal flow was lower in the immobilized calf. A negative correlation existed between maximal flow and the duration of immobilization. In the course of 6 weeks after removal of the cast, the difference in maximal flow between both sides became insignificant. Venous volume and venous emptying were not different in the two limbs. The effect of inactivity on reactive hyperaemic response may be explained by an effect of inactivity on the arterioles, muscle atrophy, a decrease in capillarization and in oxidative capacity of the muscle fibres. It is concluded that inactivity and atrophy of the lower limb musculature in patients with peripheral arterial disease may be a contributing factor to the low reactive hyperaemic response in the calf of such patients.

Adolescent↗
PubMed1984

Use of impedance plethysmography to continually monitor bone marrow blood flow.

Methods for measuring bone-blood flow are often time-consuming, tedious, single-point measurements which require sacrifice of the animal. An impedance plethysmographic technique is described which can be used to quantify temporal bone marrow blood flow changes. Results obtained with the impedance technique compare favorably with the data from simultaneously administered microspheres. Injection of sympathomimetic drugs produced measurable responses: isoproterenol caused a significant increase in bone marrow blood flow within 1 min and levarterenol decreased bone marrow blood flow. Data obtained with impedance plethysmography suggest that the technique is feasible for multiple measurements on the same animal and that the technique can be used to study acute or chronic changes in bone marrow blood flow following various experimental treatments.

Animals↗
PubMed1984

[Error magnitude of measurement sensors in air segment plethysmography].

Besides examining the properties of the material involved, this investigation assesses the so-called static and dynamic measurement errors of sensors used for air segment plethysmography. The static error which has been found with the new BN sensors amounts to 8% (old models: 31%-44%). The folding of the interior membrane of the sensor resting upon the skin, which increases proportionately to the stiffness of the material, is discussed as a source of error. If a lockable steel wrapping is employed as an exterior cover for the sensors, the static measurement error decreases by 30%-50%. These results suggest a recommendation to use a metal wrapping for the sensors as described above even with routine air segment plethysmographic examinations, and additionally to correct by mathematical means the static measurement error (which has to be determined for each sensor individually). The measurement error of the sensors of the new BN series amounts to less than 5% for a frequency of not more than 0.5 Hz; this means that blood flow values amounting to more than 50 ml/(min X 100 ml) are indicated correctly with respect to the actual frequency. If the usual linen covering is used instead of the steel cover, the linearity of the frequency is only valid up to 0.1 Hz--the corresponding blood flow value being 15 ml/(min X 100 ml).

Diagnosis, Differential↗
PubMed1984

[Evaluation of air segment plethysmography using computer tomography].

The measurement of tissue volume in the calf area carried out by computer-tomography and planimetry showed a nearly elliptic form, an average bony part of 9.9 ml (9.3%), and an average tissue volume of 97.7 ml (90.7%). When compared with the tissue volume approximation (cylinder formula) the tissue volumes thus specified were too large. The error, depending on the circumference of the calf, was about 5 to 15%. There was a difference of 5% between the venous capacity measured by computer-tomography on the one hand and air segment plethysmography on the other. The reason for this is found in the varying density of veins in the examined area. The application of the sensor on the skin caused an average reduction of 5.4% in total volume and thus in the blood volume of about 59% in the examined area. The pressure-dependent venous capacity was measured with and without application of the sensors on the skin and controlled by computer-tomography. The results showed an average difference of only 2.1%. Thus it is obviously unimportant for the results of the investigation presented, if the venous capacity is measured on the basis of the reduced total volume caused by the application of the sensors on the skin. With regard to the computer-tomographical and planimetrical control and the error of measurement discussed, the results suggest a sufficient precision of the venoextensiometry measuring the pressure-dependent venous capacity.

Blood Volume↗