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PubMed1990

[Blood flow measurement with impedance plethysmography--experimental and clinical application in orthopaedic surgery].

Impedance plethysmography has been used clinically to measure the cardiac output. We have improved the apparatus of impedance plethysmography and applied it in the orthopaedic field. It is now possible to measure the blood flow in human fingers and in the extremities of rabbits. Experimentally, we measured the blood flow through the rabbit extremities with the measured values reflecting the ischemic condition. Clinically, we measured the blood flow through the fingers with arteriosclerosis obliterans with the measured values consistent with the angiographic findings. The measurement of blood flow in vascular injuries and attachment of fingers reflected the ischemic condition. By using the impedance plethysmography, we cannot obtain an absolute value because the measured value is affected by the type of electrode and the position of the electrode. We can nevertheless seek a relative value by comparing with the values at normal site. We can also identify any differences before and at the after change in blood flow. When the advantages and disadvantages of this method are better understood, this method will be of wide clinical use.

Animals↗
PubMed1989

[Detection of acute venous thromboses using plethysmography. Possibilities and limitations].

The combined use of careful clinical examination and venous occlusion plethysmography has good diagnostic reliability. The clinical examination provides an estimated percentage "clinical probability"; in the event of negativity, complementary plethysmography enables confirmation of a negative clinical diagnosis; positive plethysmography confirms a probable clinical diagnosis or establishes the probability of thrombosis in patients with poor clinical signs. Thus false negative or false positive cases may be easily eliminated. In the remaining dubious cases complementary investigations are necessary.

Acute Disease↗
PubMed1989

[Diagnostic value of the combination of echography-plethysmography in deep venous thromboses of the legs].

The association of two non invasive methods: real time ultrasonography and plethysmography was studied prospectively for the diagnosis of deep vein thrombosis (DVT) in 70 patients. Their results were compared to contrast venography considered to the reference procedure. Venography showed DVT in 32 patients. Ultrasonography had a sensitivity of 69% and a specificity of 98%. The false negative results were related to iliac or calf vein thrombosis. Plethysmography had lower results than US (Se = 57%, Sp = 90%). In this study the sensivity of the two methods, either isolated or associated was not sufficient to allow their substitution to venography. Their association in all cases did not give better results than US alone. Because of its high specificity US can be performed first in cases of suspicion of DVT, especially in high risk patients. Plethysmography seems not to be necessary for the diagnosis.

Adolescent↗
PubMedDate not supplied

[Correlation of the size of the residual volume measured by whole body plethysmography and the single breath helium dilution method].

The value of residual volume, intrathoracic gas volume, functional residual capacity and total lung capacity obtained by the method of body plethysmography and helium dilution method was correlated by single-breath diffusing capacity. These parameters were correlated in 22 patients who had had complete functional diagnostics of the lung: spirometry, flow volume curve, body plethysmography and single-breath diffusing capacity. All findings were within normal limits, which was a condition for selection of patients for our group. Statistically significant differences (p = 0.01) of t-test were established between residual volumes by the plethysmographic and helium dilution method of single-breath diffusing capacity. The residual volume obtained by body plethysmography showed higher values for 526 ml, or 30%. The intrathoracic gas volume showed higher values for 682 ml, or 17%. Inspite of the fact that values of RV obtained by two methods had statistically significant differences, they were still within normal limits, if presented as percent of the predicted value.

Adult↗
PubMed1987

Extremity blood flow in man: comparison between strain-gauge and capacitance plethysmography.

Metabolic studies with substrate limb flux determinations require an accurate and simple method for measuring blood flow through the extremity. Two common, noninvasive methods used in recent studies are strain-gauge and capacitance venous occlusion plethysmography. The values obtained for forearm blood flow by these two methods are highly correlated in normal resting and seriously ill patients. The use of a fixed percentage of cardiac output as a measure of extremity flow was not indicative of the measured flow by either capacitance or strain-gauge plethysmography. Capacitance and strain-gauge plethysmography are comparable, noninvasive indicators of change in extremity blood flow in humans.

Cardiac Output↗
PubMed1985

Diagnosis of deep vein thrombosis. Review of clinical evaluation and impedance plethysmography.

This article has briefly reviewed the diagnosis of DVT by clinical evaluation and by impedance plethysmography. Clinical evaluation alone cannot be relied on for patient management, but when carefully performed, it remains useful in determining the need for additional testing. The medical history, especially the detection of risk factors for DVT, is as important as the physical examination. In 1,464 patients suspected of DVT, the incidence of this disease by impedance plethysmography was only 11 percent when there were no major risk factors present but increased to 50 percent when three risk factors were present. Impedance plethysmography is a widely used noninvasive test for the diagnosis of DVT. It has a sensitivity and specificity of 94 percent based on correlation with 2,561 venograms. The method is based on quantitation of the venous outflow from the calf after temporary venous occlusion in the thigh. It is particularly helpful in ruling out DVT in patients with suspicious signs or symptoms. Recent improvements in methods, including computer-assisted data analysis, appear likely to further extend its usefulness.

Computers↗
PubMed1983

[Analysis of the rebound phenomenon during outflow in plethysmography following programmed venous occlusion].

The venous outflow curve obtained using strain gauge plethysmography (Periflow JSI) frequently displays a slope change which modifies the classic exponential pattern: The semi-continuous arterial blood flow measurement together with an ECG-triggered plethysmography let the authors show the arterial origin of this slope change they called "the rebound phenomenon". Venous occlusion induces an ischemia which creates a reactive hyperemia when the venous blood current is let free. All the venous outflow curves stem from both a venous and arterial phenomenon. This latter may sometimes be of importance and has to be considered in plethysmography studies.

Adult↗
PubMed1981

[Personal experience of sleep plethysmography in the differential diagnosis of erection disturbances (author's transl)].

The authors feel that penile erection during sleep represents the first stage in the investigation of erection problems. The aim is to distinguish between psychogenic impotence the organic impotence. The authors simultaneously perform plethysmography and an electroencephalogram during sleep. Sixty five patients have been investigated in this way. In 44 cases the occurrence of nocturnal penile erection led to the conclusion of a psychogenic origin whilst in 21 cases the results of plethysmography were pathological. Amongst these 21 patients, undergoing vascular investigations, 12 underwent revascularisation of the corpora cavernosa and 12 the insertion of an erection prosthesis. It may be noted that revascularization using the epigastric artery gave widely disparate results: 2 good results amongst 9 patients, with one failure and six inadequate erections. The authors emphasise the fact that there is little alteration in sleep in cases of organic impotence and that phases of paradoxal sleep recur periodically without any great variation in the plethysmographic curve. By contrast, in functional impotence, sleep is invariably disturbed. A whole series of factors are involved in the assessment of the results: total duration of sleep, duration of paradoxal sleep, ratio of paradoxal sleep to total sleep, total erection time, total time in maximum erection and the ratio of erection time to paradoxal sleep. Analysis of sleep is thus a fundamental factor in the proper interpretation of the results of plethysmography in an importance sufferer.

Diagnosis, Differential↗
PubMed1993

Does air plethysmography correlate with duplex scanning in patients with chronic venous insufficiency?

PURPOSE: Duplex ultrasonography with distal cuff deflation was used to determine the presence and size of incompetent veins and compare the results with those of air plethysmography in patients with chronic venous insufficiency. METHODS: Thirty-two legs underwent a detailed study with both modalities. Sixteen legs had venous ulceration, six had stasis dermatitis, and ten had symptomatic varicose veins without skin changes. RESULTS: Although the venous filling index (VFI) in limbs with ulcers (5.4 +/- 3.8 ml/sec) and dermatitis (7.7 +/- 4.6 ml/sec) was significantly higher (p < 0.05) than it was in limbs with varicose veins (2.6 +/- 1.7 ml/sec), there was a large amount of overlap. Only 13% of ulcerated legs had VFI greater than 10 ml/sec. Sixty-three percent of legs with ulcers, 33% of legs with dermatitis, and 90% of legs with varicose veins had VFIs less than 5 ml/sec. Mean ejection fractions (EFs) in the three groups were similar, ranging from 45% to 52%. Combining VFI and EF did not lessen the overlap between groups. Forty-one percent of limbs with ulcers or dermatitis had air plethysmography parameters in the normal or intermediate area (VFI < 5 ml/sec; EF > 40%), which in previous studies corresponded to an incidence of ulceration of only 2%. VFI had a significant but weak correlation (r = 0.39) with the diameter of incompetent veins at the knee and a somewhat stronger relationship (r = 0.55) with the diameter of lower leg veins. Total venous volume correlated moderately well with calf vein diameter (r = 0.75). The clinical status of the leg did not correlate with the diameters of incompetent veins at the knee or calf levels. All limbs with an obstructed outflow had EFs less than 60% and ulcers or dermatitis. CONCLUSIONS: We conclude that plethysmographic measurements of functional venous parameters (VFI,EF) do not discriminate well between limbs with uncomplicated varicose veins and limbs with ulcers or stasis dermatitis and that VFI correlates poorly with the presence of incompetent veins and their diameters. Both duplex scanning and plethysmography seem to be necessary for a complete evaluation of limbs with chronic venous insufficiency.

Chronic Disease↗
PubMed1996

Plethysmography: safety, effectiveness, and clinical utility in diagnosing vascular disease.

Plethysmography, a semiquantitative method of measuring segmental blood flow and velocity in the carotid and peripheral vascular systems, is safe, easy to perform, and inexpensive. Impedance, strain guage, air, and photoelectric plethysmographic methods are assessed in this publication for their relative safety, efficacy, and clinical utility in diagnosing vascular disease. Clinical evidence has demonstrated, for example, that oculoplethysmography is not a reliable screening test for carotid artery disease, particularly in bilateral disease and nonocclusive unilateral disease. Oculoplethysmography is thus no longer recommended for the diagnosis of carotid artery disease. Impedance, strain guage, and photoplethysmography methods can be used for the initial evaluation of acute and chronic venous insufficiency, although there is great variability in the reliability of these tests to predict venous disease in the presence of nonobstructive thrombi and comorbid conditions. Strain guage and photoelectric plethysmography can be safely used for the evaluation of peripheral arterial disease. But surgical candidates for arterial reconstruction and some venous disorders may require additional imaging such as duplex ultrasound, venography, or arteriography for anatomic information that is not elucidated by plethysmography. The plethysmographic techniques reviewed in this assessment, evaluating the ability to predict the presence of flow reduction in the carotid and peripheral circulations, are based on the technical performance of the tests as compared with a reference method. Establishing evidence-based conclusions proved difficult in light of biases such as nonrandomization, unstated patient selection criteria, poor followup of patients, and lack of blindness in some studies.

Humans↗
PubMed1996

Venous strain-gauge plethysmography--reference values.

OBJECTIVE: To establish sex and age related reference values for venous strain-gauge plethysmography. DESIGN: Strain-gauge plethysmography measurements in healthy volunteers. SETTING: Examinations performed in a University Hospital (Malmö) and a County Hospital (Kalmar). PARTICIPANTS: Healthy volunteers, without history or signs of venous insufficiency. Twenty-seven men, 31 women, age range 15-74 years. MAIN OUTCOME MEASURE: Refilled volume (RV;ml/100 ml tissue), half refilling time (T50;sec), and refilling time to 90% of RV (T90;sec). RESULTS: RV; lower limit 0.6 ml/100 ml tissue. T50; lower limit 3.3 sec T90; lower limit age dependent and calculated from the ekvation: In (T90) = 3.864-0.0111 age-0.337, where in is the natural logarithm. Methodological error: RV (15%), T50 (28%), T90 (23%). CONCLUSIONS: Strain-gauge plethysmography can be used to evaluate venous insufficiency and could be especially useful in follow-up studies after therapy. Normal age and sex related reference values are needed. In this study reference values are established. Preferably RV and T90 should be used.

Adolescent↗
PubMed1997

[Digital photoplethysmography and digital "strain-gauge" plethysmography in differential diagnosis of edema].

Photoplethysmography is a noninvasive method for fast diagnosis of blood flow disturbances in the venous system of the lower limbs. It is suitable for discriminating normal from pathological venous findings. The technique has been evaluated in three groups of subjects with edema of the lower extremities. The value of this screening method in the diagnosis of vascular disorders and edema of the lower limbs is discussed. Venous occlusion plethysmography is used for discriminatory and quantitative evaluation of venous function. The diagnostic value of strain gauge plethysmography was assessed in three groups of subjects. Measured parameters were venous capacity and venous outflow. Digital photoplethysmography is suitable for the discrimination of venous edema of the lower limbs from edema caused by other factors, and digital "strain gauge" plethysmography for the discrimination of edema of the lower limbs, caused by phlebothrombosis from edema caused by other factors.

Adult↗
PubMed1977

[Comparative studies on the value of oscillography and venous occlusion plethysmography in the diagnosis of arterial occlusive diseases].

Oscillography and plethysmography in phlebembraxis also occupy an important place in the screening of arterial obstructive diseases. The two methods give reliable results. In patients who have--as was established by oscillography and clinical examination--healthy vessels, as well as in patients with arterial obstructive disease in stage II a good correspondence with the findings of plethysmography in phlebembraxis could be proved, if all the three measuring sizes (first flow, peak flow and peak flow time) were taken into consideration. Hereby the normal values given partly deviate from those ones given in literature. They are guide values which in the individual case may fall below or transgressed also in patients with healthy vessels, whereby the peak flow time is to be regarded as the most reliable measuring size. On account of the slight expenditure of time the plethysmography in phlebembraxis is suitable as screening method, however it is not sufficient as the only method for the angiological prediagnostics. It is a valuable supplementation to the hitherto known unbloody examination methods.

Angiography↗
PubMed1987

Comparison of respiratory inductive plethysmography and thoracic impedance for apnea monitoring.

Thoracic impedance apnea monitors may fail to detect obstructive apnea, may falsely alarm when the infant is breathing, and may confuse cardiac artifact with respiratory impedance. Therefore, we compared the performance of a respiratory inductive plethysmograph and a thoracic impedance monitor with a reliable measure of airflow, either nasal CO2 or pneumotachograph, during 29 studies in 28 patients referred for sleep laboratory evaluation. Sleep time averaged 72 +/- 37 (SD) minutes. The inductance plethysmography and the impedance monitor detected 99.6% +/- 0.6% and 98.3% +/- 3.0% of breaths, respectively. However, in two studies, the impedance monitor detected many extra breaths, once because of cardiac-induced impedance changes and once because of partial airway obstruction-induced impedance changes. In 11 studies, cardiac artifact was sometimes misinterpreted as a breath by the impedance monitor. The impedance monitor, but not the inductance plethysmograph, missed breaths following sighs in 16 of 29 studies. Both monitors detected all 60 episodes of central apnea. The inductance plethysmography detected 35 of 38 episodes of obstructive apnea, but the impedance monitor identified only two such events. Apnea was detected falsely four times by the inductance plethysmograph and 14 times by the impedance monitor. These results suggests that a respiratory inductive plethysmograph would have significant advantages over impedance monitoring, including the ability to detect obstructive apnea, and freedom from cardiac artifact.

Apnea↗
PubMed1992

Exercise strain-gauge venous plethysmography: evaluation of a "new" device for assessing lower limb venous incompetence.

Plethysmography can be used to detect and assess venous incompetence in the lower extremities. The authors recently evaluated a new device designed for this purpose that uses strain gauges to determine changes in lower extremity circumference occurring with (and immediately after) exercise. The device plots a curve of volume against time for each limb and automatically calculates key values such as the volume of blood expelled from the lower limb veins during exercise and the time required for the veins to refill following exercise. The apparatus was incorporated into their noninvasive vascular laboratory and used (along with other standard tests) to study patients referred for suspected venous incompetence. They observed the following: (1) A shortened postexercise refilling time accurately identified limbs with venous incompetence. (2) The clinical severity of venous incompetence was inversely related to the refilling time. (3) Exercise-induced changes in lower extremity volume correlated well with simultaneously determined changes in venous pressure. (4) Valvular incompetence could be localized to the deep or superficial veins based upon the improvement in refilling times seen following placement of elastic tourniquets around the lower limb. (5) The type of exercise performed (knee bends while the patient was standing versus ankle reflexes while sitting) had little effect on results. The authors conclude that exercise venous plethysmography is a useful noninvasive tool for assessing lower limb venous incompetence.

Blood Volume↗
PubMed2004

Detection of mediator-induced airway constriction by barometric plethysmography in mice.

The barometric method has recently been employed to detect airway constriction in small animals. This study was designed to evaluate the barometric method to detect mediator-induced central and peripheral airway constriction in BALB/c mice. First, the central airway constrictor carbachol and the peripheral airway constrictor histamine were employed to induce airway constriction, which was detected by both the conventional body plethysmography and the barometric method in anesthetized mice. Second, bronchoconstriction induced by aerosolized carbachol or other mediators was detected with the barometric plethysmography in conscious, unrestrained mice. Carbachol inhalation caused about four-fold increase in pulmonary resistance (RL) and about two-fold increase in enhanced pause (Penh) in anesthetized mice. In contrast, in the same preparation, histamine aerosol induced a decrease in dynamic compliance (Cdyn), with no alteration in RL or Penh. In awake mice, carbachol and methacholine caused increases in Penh, frequency, and tidal volume (VT). On the other hand, histamine, histamine + bradykinin, and prostaglandin-D2 did not alter Penh but decreased VT in conscious mice. These data suggest that there was no sufficient evidence to indicate that Penh could be a good indicator of bronchoconstriction for the whole airways.

Air Pressure↗
PubMed1976

Impedance plethysmography: evaluation of a simplified system of electrodes for the measurement of blood flow in the lower limb.

Venous occlusion plethysmography was used to measure the flow of blood into the lower limbs of 30 normal volunteers. An impedance plethysmograph, using disposable point electrodes, was compared with a mercury in Silastic strain gauge plethysmograph in 20 subjects. The effect of changes in the configuration of the point electrodes was studied in 10 subjects. Impedance plethysmography was shown to be reproducible, and one particular configuration of point electrodes was shown to be superior to the others.

Blood Flow Velocity↗
PubMed1986

Venous muscle pump function in patients with primary lymphoedema: assessment by ambulatory strain gauge plethysmography.

The musculovenous pump function was assessed by ambulatory strain gauge plethysmography in 11 patients with primary lymphoedema. The venous function was within the normal range regarding both venous reflux and expelled volume. The values were compared with ten patients with chronic venous insufficiency and oedema. The values for venous function were clearly abnormal for the patients with venous insufficiency and different from those with primary lymphoedema. Ambulatory strain gauge plethysmography may be a useful non-invasive method in distinguishing between oedema of lymphatic or venous origin.

Adult↗