Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLETHYSMOGRAPHY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1987

Measurement of cardiac output by electrical impedance plethysmography.

There are many potential applications for cardiac output measurement in clinical and experimental medicine. The most commonly used techniques are invasive procedures, requiring cardiac or arterial catheterization, a disadvantage that has restricted their wider application. Impedance plethysmography has been developed as a non-invasive, beat-by-beat method of cardiac output measurement, which provides an estimate of stroke volume from changes in the electrical impedance of the thorax during cardiac systole. The values for cardiac output obtained by this technique have been extensively compared with values obtained by other methods, both in experimental animals and in the human subject. In the majority of studies high correlation coefficients have been obtained, although impedance plethysmography has tended to give higher absolute values than most other methods. Values for cardiac output obtained by impedance plethysmography are best assessed by comparison with a series of normal values obtained by this technique, rather than with values obtained by other methods. We discuss the results of an investigation of normal cardiac output by impedance plethysmography; theoretical objections to impedance cardiography are considered, and various methods of determining the specific resistivity of blood are reviewed.

Adolescent↗
PubMed2003

Pilot study of vaginal plethysmography in women treated with radiotherapy for gynecological cancer.

OBJECTIVE: After pelvic radiotherapy for gynecological cancer, changes in the vaginal epithelium might influence sexual arousal and satisfaction, leading to dyspareunia and relational problems. The aim of the study was to determine the feasibility of vaginal plethysmography in order to measure physical late effects of this therapy on sexual function. METHODS: Patients treated with radiotherapy for cervical, endometrial, or ovarian cancer, who were in complete remission for over 1 year, underwent vaginal plethysmography to measure changes in vaginal vasocongestion, while watching erotic video fragments. Afterward two questionnaires, designed to measure feelings of sexual arousal during the video, and to identify sexual dysfunction, were completed. The results were compared with those of healthy women. RESULTS: Patients (n = 9) and volunteers (n = 8) did not differ in baseline amplitude of plethysmography and showed comparable changes in vaginal vasocongestion during the various video fragments. The decline in amplitude during the last video fragment in the patient group did not reach significance, but the group of patients is small and heterogeneous. Addressing subjective sexual arousal during the video, patients reported less feelings of lust and desire and fewer bodily sensations while watching than the controls. Patients worried more about the sexual satisfaction of their partners than controls. CONCLUSION: Vaginal plethysmography can be used to measure vaginal vasocongestion in patients treated with radiotherapy to the proximal vagina. In this pilot study the changes of vaginal vasocongestion during sexual arousal between patients and healthy volunteers were not different. This correlates with a comparable sexual satisfaction, although patients reported less feelings of lust.

Adult↗
PubMed2003

Finger plethysmography--a method for monitoring finger blood flow during sleep disordered breathing.

We investigated a non-invasive measurement for changes in finger blood flow during wakefulness and sleep. Changes in finger blood flow, reflected by pulse wave amplitude (PWA) derived from finger plethysmography, were compared with changes in forearm vascular flow assessed by venous occlusion plethysmography after intra-arterial infusion of norepinephrine (NE), phentolamine, and isoproterenol (n=15, 15, 14 subjects, respectively). Moreover, PWA was assessed during obstructive breathing during sleep (n=8 patients). Vasoconstriction in the finger (PWA) was stronger than that obtained in the forearm vascular bed in the higher NE dose range both without (ANOVA, P=0.002) and with concomitant phentolamine-induced alpha-receptor blockade (P=0.02). Isoproterenol increased forearm blood flow but did not induce flow changes detectable by the finger plethysmographic technique (P<0.001). PWA was significantly reduced during arousal from obstructive sleep apnea (-37.5+/-16.1%, P=0.002, n=6 patients), suggesting vasoconstriction in the digital vascular bed. PWA derived from finger plethysmography allows continuous, non-invasive measurement of changes in finger blood flow during wakefulness and sleep. However, as may be expected from the anatomical and functional differences between the finger and forearm vascular beds and demonstrated by the lack of response to beta(2)-receptor stimulation, PWA does not mimic forearm vascular flow characteristics. Thus, finger plethysmography may be a useful complement to current vascular research techniques, in particular to monitor sympathetic influences on skin blood flow in the finger.

Adrenergic alpha-Antagonists↗
PubMed2005

Reproducibility of blood flow and post-occlusive reactive hyperaemia as measured by venous occlusion plethysmography.

Venous occlusion plethysmography is commonly used as a tool to assess BF (blood flow) and VR (vascular resistance) at baseline and during PORH (post-occlusive reactive hyperaemia). However, little is known about the reproducibility of this method. The purpose of the present study was to investigate short- (hours) and medium (week)-term reproducibility of forearm, calf and thigh BF and VR at baseline and during PORH. Reproducibility was assessed by the CV (coefficient of variation). In eight subjects, baseline BF and VR of the forearm, calf and thigh were measured using venous occlusion plethysmography (50 mmHg). PORH and minimal VR were measured after 13 min of arterial occlusion (220 mmHg). Reproducibility of baseline forearm and calf BF was acceptable and in agreement with previous studies (CV, 12.9-21.2%). Short- and medium-term reproducibility of thigh BF was good (CV, 5.9% and 8.7% respectively). Baseline VR showed acceptable-to-good reproducibility for forearm, calf and thigh (8.3-22.5%). Forearm PORH showed a CV of 6.1% (short term) and 8.6% (medium term); this was 6.1% (short term) and 6.4% (medium term) for the calf and 6.4% (short term) and 8.0% (medium term) for the thigh. Minimal VR showed good-to-acceptable reproducibility (CV, 6.1-11.7%). In conclusion, forearm, calf and thigh BF and PORH measured by plethysmography have an acceptable-to-good short- and medium-term reproducibility. Short- and medium-term reproducibility of forearm and calf baseline BF are acceptable and thigh baseline BF has a good short- and medium-term reproducibility. Therefore plethysmography is a suitable low-cost tool to assess thigh baseline BF and PORH.

Adult↗
PubMed2002

The role of strain gauge plethysmography in the assessment of patients with suspected deep vein thrombosis.

Suspicion of deep vein thrombosis (DVT) is a common reason for medical referral to hospital. Clinical signs and symptoms are notoriously unreliable, hence there is the need for objective testing. Strain gauge plethysmography (SGP) has been marketed as a technique for excluding lower limb DVT. We therefore set out to evaluate this screening tool. Over a 2 year period, 437 consecutive patients referred with suspected DVT were assessed using both plethysmography and Doppler ultrasound. When the two techniques were compared, plethysmography was found to have a negative predictive value of 90%. We conclude that strain gauge plethysmography has a role in the screening of patients with suspected DVT but should not be used as the sole method in patient assessment.

False Negative Reactions↗
PubMed1986

Assessment of peripheral hemodynamics using impedance plethysmography.

Impedance plethysmography (IPG) is a safe, noninvasive method for measuring peripheral hemodynamics. The purpose of this article is to describe the IPG technique and its potential use by physical therapists in making hemodynamic evaluations. Impedance plethysmography requires the attachment of four circumferential Mylar band electrodes around a limb. We use a cardiograph to introduce a 4-mA current (I) at a frequency of 100 kHz in the two outer electrodes. The voltage (V) is sensed in the two center electrodes, and the resulting impedance (Z) is calculated using Ohm's law (Z = V/I). Arterial blood flow can be calculated using an impedance-related volume conduction equation. Impedance plethysmography has been shown to be economical, and any limb or limb segment can be evaluated. Applications are presented for the assessment of arterial blood flow, peripheral arterial disease, deep vein thrombosis, and venous insufficiency. Impedance plethysmography offers the physical therapist a safe and relatively simple technique to assess the peripheral vascular status of the patient.

Chronic Disease↗
PubMed2000

Computer-assisted venous occlusion plethysmography in the diagnosis of acute deep venous thrombosis.

Suspicion of deep venous thrombosis (DVT) is a common reason for acute medical admission. The clinical diagnosis is difficult, and thus significant numbers are investigated and found to be normal. Provision of 24-h radiology is costly, and there may be a delay in investigation. We assessed computer-assisted venous occlusion plethysmography as a screening test for DVT, compared with standard radiology. The test has the advantage of being performed on the ward and if reliable would significantly reduce the number of radiological investigations required. We enrolled 215 consecutive patients presenting with the possible diagnosis of DVT, of whom 144 had technically adequate plethysmography results. Plethysmography had a sensitivity of 96% (95%CI 88-99%) and a negative predictive value of 97% (95%CI 91-99%). Patients excluded because of technically inadequate results were older (by a mean 7 years, p=0. 003). Computer-assisted venous occlusion plethysmography is a non-invasive method of rapidly screening for DVT which may be safely used as an initial screening test. The test is less useful in older patients, or patients unable to keep still for a period of 2 min.

Acute Disease↗
PubMed2004

Monitoring body fat in the elderly: application of air-displacement plethysmography.

PURPOSE OF REVIEW: This review will focus chiefly on recently published studies utilizing air-displacement plethysmography (i.e. BOD POD) in geriatric populations. This innovative technology has been available commercially since 1995. As the test procedure is relatively easy to perform and quick, it may provide an improvement in body composition testing, especially in older individuals with poor ambulation and health. RECENT FINDINGS: This review will explain in a concise and detailed manner the underlying principles of air-displacement plethysmography specifically related to the BOD POD. Second, it will review the studies using this new technology in comparison with more commonly used techniques (hydrostatic weighing, dual energy X-ray absorptiometry, deuterium oxide, multi-compartmental models) for body composition analysis in geriatric populations. Third, it will provide a direction for future studies. SUMMARY: A review of the current body of literature in which air-displacement plethysmography was used is beginning to emerge with a clear picture. Although this technique is still new, it appears that air-displacement plethysmography is a valid and reliable alternative to more traditional body composition techniques, as indicated by small mean differences between techniques. This has special implications in a geriatric population because traditional techniques are difficult to perform in individuals with joint pain, ambulation issues, and overall poor health.

Absorptiometry, Photon↗
PubMed1980

A modified 125I-fibrinogen technique in suspected deep vein thrombosis. A comparison with plethysmography and phlebography.

The diagnostic efficiencies of a modified 125I-fibrinogen uptake test (FUT), venous strain gauge plethysmography, and the routine report on phlebography were compared in 301 consecutive patients with suspected deep vein thrombosis (DVT) in the leg. A keen, independent review of the phlebography films was used as the reference method. The FUT detected 62% of all thrombi after one hour, 71% after one day, and 98% after two days. False positive results were, however, found after two days in 52% of all patients without DVT. Plethysmography revealed 63% of the thrombi and was falsely positive in 23% of patients without DVT. The routine examination of phlebography films revealed only 86% of the thrombi seen at the final independent review. The routine report was falsely positive in 6% of patients without thrombi. Consequently, the modified FUT is a useful screening test; at one hour it was equally sensitive to DVT as plethysmography and after two days it excluded DVT with a significantly better sensitivity than the routine report on phlebography. Drawbacks of FUT are the delay of the diagnosis in some patients and the low specificity. In patients with a pathological FUT, further investigation is often required. Plethysmography is not recommended as a screening test, since it lacks both sensitivity and specificity.

False Positive Reactions↗
PubMed1986

Thermography and plethysmography in the diagnosis of deep venous thrombosis--a comparison with phlebography.

Ninety-two patients with suspected unilateral deep venous thrombosis (DVT) in the lower limb were examined by thermography, plethysmography and phlebography. ROC analysis (Receiver Operating Characteristics) was used to evaluate discrimination thresholds and to compare thermography and plethysmography (four variables) with phlebography. The sensitivity of thermography, 85% (94% for out-patients), was higher than that of plethysmography (58-79%) for the discrimination thresholds chosen. The specificity of thermography was low, 39% (42% for out-patients) or 55%, if obvious relevant clinical findings were included in the evaluation. The specificity of plethysmography was much higher (80-97%). Optimum combination of the four plethysmographic variables showed predictive values of 93-94%, while combination of thermography and plethysmographic variables showed higher predictive values (95-97%), mostly because of a higher sensitivity of thermography for distal DVT. A possible reduction of the number of phlebographic examinations by at least 50% and a cost reduction of 25% could have been obtained without any appreciable loss of diagnostic accuracy. A follow-up study of 112 consecutive patients, examined according to the recommended screening method, showed a reduction of phlebographic examinations by 62%.

Acute Disease↗
PubMed2004

Plethysmography without venous occlusion for measuring forearm blood flow: comparison with venous occlusive method.

Limb blood flow is widely used as an indicator of the human vascular properties. There are only few non-invasive methods for its measurement such as venous occlusion plethysmography. However, several authors have questioned its validity. The problems appear to be related to the process of venous occlusion. We developed two methods to measure forearm blood flow by plethysmography without venous occlusion in combination with Doppler velocimetry (without imaging). Method 1: the gradient of a tangent drawn on the latter part of the down stroke of the plethysmographic volume pulse is an approximation of venous blood flow in the absence of diastolic blood flow. At equilibrium, it equals the average arterial flow in a cardiac cycle. The Doppler velocity waveform recorded simultaneously allows improvement of this approximation when there is diastolic blood flow. Method 2: the volume pulse detected by a plethysmograph calibrated in absolute volume is used to calibrate the velocity waveform recorded simultaneously to produce an approximation of arterial volumetric flow waveform. Bland-Altman analysis shows both methods have good correlation and agreement with venous occlusion plethysmography at rest. Method 1: mean difference (blood flow measured by venous occlusion minus calculated flow) = 0.10 ml/pulse (+/-0.18), limits of agreement = -0.41 and 0.61 ml/pulse. Method 2: mean difference = -0.041 ml/pulse (+/-0.15), limits of agreement = -0.45 and 0.37 ml/pulse. During hyperaemia, venous occlusion plethysmography grossly underestimated relative to the new methods. The new methods are not dependent on venous occlusion and produce consistent results with or without hyperaemia.

Adult↗
PubMed2006

Investigating pulmonary embolism in the emergency department with lower limb plethysmography: the Manchester Investigation of Pulmonary Embolism Diagnosis (MIOPED) study.

OBJECTIVES: To measure the diagnostic accuracy of computerised strain gauge plethysmography in the diagnosis of pulmonary embolism (PE). METHODS: Two researchers prospectively recruited 425 patients with pleuritic chest pain presenting to the emergency department (ED). Lower limb computerised strain gauge plethysmography was performed in the ED. All patients underwent an independent reference standard diagnostic algorithm to establish the presence or absence of PE. A low modified Wells' clinical probability combined with a normal D-dimer excluded PE. All others required diagnostic imaging with PIOPED interpreted ventilation perfusion scanning and/or computerised tomography (CT) pulmonary angiography. Patients with a nondiagnostic CT had digital subtraction pulmonary angiography. All patients were followed up clinically for 3 months. RESULTS: The sensitivity of computerised strain gauge plethysmography was 33.3% (95% confidence interval (CI) 16.3 to 56.2%) and specificity 64.1% (95% CI 59.0 to 68.8%). The negative likelihood ratio was 1.04 (95% CI 0.68 to 1.33) and positive likelihood ratio 0.93 (95% CI 0.45 to 1.60). CONCLUSIONS: Lower limb computerised strain gauge plethysmography does not aid in the diagnosis of PE.

Adult↗
PubMed2005

Radionuclide plethysmography for noninvasive evaluation of peripheral arterial blood flow.

We validated a noninvasive radionuclide plethysmography technique to evaluate peripheral arterial blood flow during reactive hyperemia. This method, based on the measurement of blood volume variations during repetitive venous occlusions, was compared with strain-gauge venous impedance plethysmography. The technique uses 99mTc-labeled autologous red blood cells scintigraphy to determine the rate of change of forearm scintigraphic counts during venous occlusion. Thirteen subjects were simultaneously evaluated with radionuclide and impedance plethysmography. Six baseline flow measurements were performed to evaluate the reproducibility of each method. Twenty-seven serial measurements were then made to evaluate flow variation during forearm reactive hyperemia. After 30 min of recovery, resting forearm blood flows were again evaluated. Impedance and radionuclide methods showed excellent reproducibility with intraclass correlation coefficients of 0.96 and 0.93, respectively. There was also good correlation of flows between both methods during reactive hyperemia (r = 0.87). Resting flows at 30 min after reactive hyperemia were slightly lower than at baseline with both methods. We conclude that radionuclide plethysmography could be used for the noninvasive evaluation of forearm blood flow and its dynamic variations during reactive hyperemia.

Aged↗
PubMed1990

Serial impedance plethysmography in pregnant patients with clinically suspected deep-vein thrombosis. Clinical validity of negative findings.

STUDY OBJECTIVE: To determine the safety of withholding anticoagulant therapy in pregnant patients with clinically suspected deep-vein thrombosis who have negative results by serial impedance plethysmography. DESIGN: Prospective study evaluating prognosis by long-term follow-up to 3 months postpartum in all patients. SETTING: University-affiliated community hospital and referral center. PATIENTS: One hundred fifty-two consecutive pregnant patients referred with clinically suspected deep-vein thrombosis. All patients completed the study. INTERVENTIONS: Anticoagulant therapy was withheld in 139 patients negative by serial impedance plethysmography, and the patients were followed long term. MEASUREMENTS AND MAIN RESULTS: None of 139 patients (0%; 95% CI, 0% to 2.6%) had symptomatic pulmonary embolism or recurrent venous thrombosis. CONCLUSIONS: The findings establish the safety of withholding anticoagulant therapy in pregnant patients who have negative results after serial impedance plethysmography. Sufficient patients were entered to provide narrow confidence intervals on the outcomes observed in patients with negative findings by impedance plethysmography. These findings are similar to those seen after venography in symptomatic patients. These data extend the role of non-invasive testing in patients with clinically suspected deep-vein thrombosis to the pregnant symptomatic patient.

Adolescent↗
PubMed1992

Detection of deep vein thrombosis with impedance plethysmography and real-time compression ultrasonography in hospitalized patients.

BACKGROUND: Serial testing with impedance plethysmography or compression ultrasonography has been demonstrated to be feasible and accurate for the detection of deep vein thrombosis (DVT) in symptomatic outpatients, and these techniques are replacing contrast venography in this patient category. Limited data, however, are available on the clinical utility of these noninvasive tests in symptomatic hospitalized patients. The objectives of our study were to determine the feasibility of ascending contrast venography and to evaluate the accuracy of these two noninvasive methods for the detection of DVT in symptomatic hospitalized patients. METHODS: A prospective, "blind" comparison of impedance plethysmography and compression ultrasonography with ascending contrast venography was performed in consecutive hospitalized patients with clinically suspected DVT of the leg. RESULTS: Of the 127 potentially eligible patients, 44 had to be excluded; 25 of these could not undergo venography (feasibility of venography, 80.3%). The sensitivity, specificity, and positive and negative predictive values of impedance plethysmography for proximal DVT were 96%, 83%, 82%, and 97%, respectively. For compression ultrasonography, these measures for proximal DVT were 97%, 86%, 87%, and 97%, respectively. The overall prevalence of DVT was 53%, of which 85% was located proximally. CONCLUSIONS: Contrast venography cannot be performed in about 20% of consecutive symptomatic patients. Both impedance plethysmography and compression ultrasonography are feasible and valid alternatives to contrast venography in the diagnostic treatment of these patients.

Feasibility Studies↗
PubMed1992

Assessment of acute and old deep venous thrombosis in upper extremity by venous strain gauge plethysmography.

The purposes of this study were to evaluate the efficiency of occlusion strain gauge plethysmography in the diagnosis of symptomatic deep venous thrombosis in upper extremities, to compare early (one month) and late clinical evolution (many years) to plethysmography data and, finally, to set up normal and pathological values. Four groups of patients were tested. Sixteen patients with confirmed acute thrombosis, 6 patients with unconfirmed thrombosis, 15 with an old thrombosis (mean follow-up: 7 years) as well as 15 healthy volunteers. The outflows measurements were significantly lowered (p less than 0.05) in the arms with acute thrombosis compared to the contralateral arms, to the affected arms of patients with thrombosis excluded and to both volunteers' arms. Pathological values for the different outflow parameters could be defined as follows: Maximum venous output less than 110 ml/100 ml/minute, Outflow after 3 seconds less than 1.2 ml/100 ml, Strandness index less than 0.16. On month after the acute episode we found a good correlation between the usually favourable clinical evolution and venous haemodynamics assessed by plethysmography. The mild late post-thrombotic syndrome of most patients with an old thrombosis was not well demonstrated by plethysmography.

Adult↗
PubMed1990

[Study of vasomotility in man using plethysmography and flowmetry].

The interpretation of cardiac hemodynamics is indissociable from the study of the peripheral vascular circulation. The latter may now be assessed by non-invasive techniques. Measuring the systemic blood pressure is useful but, in itself, insufficient. The venous sector is usually studied by plethysmographic methods. The commonest of those is occlusion plethysmography either with a mercury gauge or by impedence plethysmography. It is possible to measure venous distensibility, the venous tone. Postural plethysmography improves the study protocol by eliminating the artefact of venous occlusion while respecting the spatial cardiovascular adaptation. The study of the permeability of the capillary walls is a useful complement to venous investigations. Arterial function is approached routinely by qualitative plethysmography which provides little useful information; on the other hand, the measurement of mean arterial blood flow gives a quantitative and physiologically useful parameter. Even better than the mean arterial flow is the pulsatile arterial blood flow which may be measured by pulsed wave Doppler echo, non-invasive electromagnetic flowmetry and NMR flowmetry. Cutaneous blood flow is measured by laser Doppler. It is now possible to measure global pulsatile arterial flow of a segment of limb including its principal and collateral arteries, or the blood flow of a selected artery or even cutaneous blood flow alone. Future trends lie in improving the accuracy of all these measurements of flow and in increasing the possibilities of controlling tissue metabolism. In addition, studies in the microcirculation will become increasingly important: capillary flow, intracapillary distribution, transcapillary exchanges.

Capillary Permeability↗
PubMed1990

[Sensitivity and specificity of multi-frequency oscillation methods, body plethysmography and spirometry in 5-8-year-old asthmatic patients].

We compared specificity and sensitivity of the forced oscillation technique with the standard methods of body plethysmography and spirometry in children suffering from asthma (age 5-8 yrs). We investigated 60 healthy and 66 asthmatic children by forced oscillation, plethysmography and spirometry. Mean FEV1% pred was 99.7 and 82.4% in the healthy and asthmatic subjects, respectively, and mean SRaw was 0.68 and 1.18 kPa*s, respectively. Forced oscillation and plethysmography could be measured in all children, whereas 29% of the investigated children failed to perform valid spirometry. Discriminant analysis was used to compare the optimal classification which could be obtained from the measured data with the clinical one. Fixing specificity to 95%, we computed sensitivities of 66% (forced oscillation), 68% (body plethysmography), and 76% (spirometry). We conclude that the diagnostic value of the three methods in young children with asthma is similar. However, the value of spirometry is limited by cooperation in these young children.

Asthma↗