PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Plethysmography”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1985

A comparison of impedance plethysmography and strain gauge plethysmography in the diagnosis of deep venous thrombosis in symptomatic outpatients.

Strain gauge plethysmography and impedance plethysmography are non-invasive diagnostic techniques for deep venous thrombosis. In 145 consecutive out-patients presented with suspected acute deep venous thrombosis we compared these two techniques. Venography was performed if one or both tests were positive. Both tests were repeatedly normal in 91 (63%) patients, while in 38 (26%) patients both tests were abnormal and venography confirmed the presence of venous thrombosis. In six other patients the impedance plethysmography test result and venography were positive while the result of the strain gauge plethysmography test was normal. This difference was statistically significant (p less than 0.001). Four of these six patients had acute proximal thrombosis of the deep leg veins. The impedance plethysmography was falsely positive in four patients while strain gauge plethysmography was falsely abnormal in one patient. We conclude that in the diagnostic management of patients with suspected deep venous thrombosis, impedance plethysmography is superior to strain gauge plethysmography.

Diagnostic Errors↗
PubMed1990

Visual sexual stimulation plethysmography: complementary test to nocturnal penile plethysmography.

Diurnal penile plethysmography under visual sexual stimulation (VSS) and nocturnal penile tumescence (NPT) plethysmography have been performed in 5 healthy volunteers and 195 consecutive men complaining of impotence. Our study demonstrates that VSS plethysmography may compensate at least partially for the shortcomings of classic NPT plethysmography, by allowing direct clinical estimation of "erectile performance." Twenty percent of the patients had full erection under VSS. These patients do not need further testing. VSS is a noninvasive and useful "first-line" investigation in erectile dysfunction.

Diabetes Mellitus↗
PubMed1992

The judicial use of venous duplex imaging and strain gauge plethysmography (single or combined) in the diagnosis of acute and chronic deep vein thrombosis.

Sixty-eight patients (79 limbs) with clinically suspected deep vein thrombosis were evaluated by duplex imaging, strain gauge plethysmography and venography. The diagnostic accuracies were projected over a spectrum of disease incidences ranging from 10 to 90 per cent of the population. The sensitivity, specificity, positive and negative predictive values, and over-all accuracy in detecting acute deep vein thrombosis were 90.9, 87.1, 83.3, 93.1, and 88.7 per cent, respectively, for venous duplex imaging, and 81.8, 69.6, 56.3, 88.9 and 73.5 per cent, respectively, for strain gauge plethysmography. The positive predictive value and over-all accuracy of venous duplex imaging were statistically significantly higher than that of strain gauge plethysmography. When both tests were combined and compared with venous duplex imaging alone, none of these parameters were statistically significant. For chronic deep vein thrombosis, the sensitivity, specificity, positive predictive value, negative predictive value and over-all accuracy for venous duplex imaging were 75, 86, 80, 86 and 82 per cent, respectively. Fourteen per cent had inconclusive results obtained at venous duplex imaging. When strain gauge plethysmography was combined with venous duplex imaging, the over-all accuracy was 82 per cent. As the true incidence of the disease increases, the positive accuracy differences between strain gauge plethysmography and venous duplex imaging decrease to a negligible level. We concluded that over-all, venous duplex imaging is superior. However, the strain gauge plethysmography has reasonable accuracy and may be used in places where venous duplex imaging is not available. Combined use of venous duplex imaging and strain gauge plethysmography would be helpful in patients with inconclusive results obtained at venous duplex imaging and, as the true incidence increases, the positive accuracy rate of strain gauge plethysmography becomes close to that of venous duplex imaging.

Acute Disease↗
PubMed1985

Diagnostic efficacy of impedance plethysmography for clinically suspected deep-vein thrombosis. A randomized trial.

Impedance plethysmography is an accurate noninvasive method to test for proximal vein thrombosis, but it is insensitive to calf-vein thrombi. We randomly assigned patients on referral with clinically suspected deep-vein thrombosis and normal impedance plethysmographic findings to either serial impedance plethysmography alone or combined impedance plethysmography and leg scanning (which has been shown to be essentially as sensitive as venography) and compared the long-term outcomes. During the initial surveillance, deep-vein thrombosis was detected in 6 of 311 patients (1.9%) tested by serial impedance plethysmography alone and in 30 of 323 patients (9.3%) (most with calf-vein thrombi) tested by the combined approach (p less than 0.001). During long-term follow-up, no patient died from pulmonary embolism; but 6 patients (1.9%; 95% confidence limits, 0.7% to 4.2%) tested by serial impedance plethysmography developed deep-vein thrombosis compared with 7 patients (2.2%; 95% confidence limits, 0.9% to 4.4%) tested by the combined approach. Serial impedance plethysmography used alone is an effective strategy to evaluate such symptomatic patients.

Adult↗
PubMed1989

Calibration of respiratory inductive plethysmography during quiet and active sleep in lambs.

Respiratory inductive plethysmography provides a noninvasive method of measuring breathing patterns. Calibration of respiratory inductive plethysmography requires calculation of gain factors for ribcage and abdomen transducers utilizing 2 breathing patterns with different ribcage and abdomen contributions and tidal volume measured by either spirometry or integrated pneumotachography. The purpose of this study was to determine if respiratory inductive plethysmography can be calibrated to provide accurate measurements during quiet and active sleep in lambs. We used a least squares linear regression calibration technique with breaths selected from quiet sleep and active sleep to calculate gain factors in 6 tracheostomized lambs. Validation of gain factors was performed by comparing tidal volumes obtained simultaneously by respiratory inductive plethysmography and pneumotachography during quiet sleep and active sleep. Tidal volume differences between respiratory inductive plethysmography and pneumotachography on validation runs of 15 consecutive breaths each revealed 90% of validation breaths within +/- 20% during quiet sleep and 82% of validation breaths within +/- 20% during active sleep. These data provide evidence that respiratory inductive plethysmography can be calibrated to allow breathing pattern measurement during sleep.

Animals↗
PubMed1988

Lower-extremity venous thrombosis: comparison of venography, impedance plethysmography, and intravenous manometry.

This study was undertaken to compare impedance plethysmography with lower-extremity venography and venous manometry in the diagnosis of acute deep venous thrombosis (DVT) of the lower extremity. Ninety-six extremities were studied. In this population, in which the prevalence of acute DVT was 43.8%, plethysmography had a sensitivity of 86.8% and a specificity of 72.0%. The predictive value of abnormal findings at plethysmography was 70.2%, and the predictive value of normal findings at plethysmography was 87.8%. Venous manometry was performed successfully in 89 extremities. A statistically significant difference was shown in the mean intravenous pressure between patients with and without acute DVT. However, there was considerable overlap between the two populations, limiting the predictive value of impedance plethysmography in any given patient.

Adult↗
PubMed1988

Diagnosis of femoropopliteal venous thrombosis: comparison of duplex sonography and plethysmography.

Duplex sonography and impedance plethysmography were correlated with contrast venography to compare the sensitivity, specificity, and accuracy of the two noninvasive techniques for the diagnosis of femoropopliteal venous thrombosis. Sensitivity, specificity, and accuracy of duplex sonography were 90%, 100%, and 97%, respectively, when compared with venography in 32 patients. Sensitivity, specificity, and accuracy of plethysmography were 100%, 63%, and 72%, respectively, when compared with venography in 25 patients. In 21 patients, plethysmography was either nondiagnostic or could not be done because of clinical difficulties. Eighteen of these patients had diagnostic duplex examinations. Duplex sonography exhibits similar sensitivity but higher specificity than plethysmography. Duplex sonography also permits diagnostic examinations in patients in whom diagnostic plethysmography cannot be performed.

Adult↗
PubMed1988

Utility of impedance plethysmography in the diagnosis of recurrent deep-vein thrombosis.

Serial impedance plethysmography has been shown to be a safe and effective alternative to venography in the management of patients with clinically suspected acute venous thrombosis. The rate of normalization of an initial abnormal impedance plethysmogram and, consequently, the usefulness of impedance plethysmography in the management of patients with recurrent symptoms is, however, unknown. In a prospective cohort follow-up study, 161 consecutive patients with proved venous thrombosis and abnormal impedance plethysmograms were studied for one year. After 3, 6, 9, and 12 months, the impedance plethysmograms had normalized in 67%, 85%, 92%, and 95% of the patients, respectively. Thirty-five patients (22%) returned with clinically suspected recurrent thrombosis, of whom 31 had normal impedance plethysmograms prior to their return. In 18 of these patients, repeated tests were normal; these patients did not undergo anticoagulant therapy, and follow-up disclosed no subsequent adverse consequences. In the other 13 patients, the test again became abnormal; 11 patients were shown by venograms to have recurrent deep-vein thrombosis. Consequently, 29 (83%) of the 35 patients in whom the suspicion of recurrent thrombosis arose could have been managed with impedance plethysmography alone without the necessity for venography or anticoagulant therapy. It is concluded that normalization of impedance plethysmography tests occurs in almost all patients within nine months, and that serial impedance plethysmography is useful for patient management in nearly 90% of patients presenting with recurrent symptoms.

Acute Disease↗
PubMed1986

Comparison of Doppler and strain-gauge plethysmography to detect vasculogenic impotence.

Doppler penile-pressure determinations to diagnose vasculogenic impotence require an experienced technician, can be time-consuming, yield inconsistent results and require much penile manipulation. Therefore the authors assessed and compared strain-gauge plethysmography as an alternative noninvasive procedure. Sixty-one patients with erectile failure had penile blood pressure determined by Doppler and indium-gallium alloy in Silastic strain-gauge plethysmography. Penile brachial indices were calculated. Strain-gauge results agreed with the Doppler measurements in all but three patients whose indices were found to be normal by Doppler and borderline by strain-gauge plethysmography. The sensitivity, accuracy and specificity of strain-gauge plethysmography were 93%, 95% and 100% respectively. Doppler determinations required an average of 20 minutes to perform, strain-gauge measurements only 4. The authors conclude from this study that strain-gauge plethysmography is a rapid, reliable, accurate method of determining penile blood pressures.

Blood Pressure↗
PubMed1987

[Variations in venous physiology in the healthy subject. Postural and venous occlusion plethysmography studies].

The principal characteristic of the venous network is its distensibility, the reason for its role as blood reservoir and cardiovascular adaptation system. This distensibility varies continuously as a function of venous tone, of neurocardiovascular adaptation and of the method used for its determination. The importance of variability of venous physiology was investigated by postural and venous occlusion plethysmography. Two series of tests were performed in 3 healthy volunteers, each being treated over one month: one series involved 19 determinations during May 1985, the other 14 determinations in December 1985. Two plethysmographic methods were employed: conventional venous occlusion plethysmography in decubitus with compression of 50 mm Hg and postural plethysmography with venous occlusion only, using gravity force during variations in position of subjects. Venous filling, a function of venous distensibility, varied between 16.7 and 17.8% during venous occlusion and 23.9 and 31.7% during postural plethysmography. Emptying half-life was from 20.7 to 40.7%. Emptying rate was, by the 6th second, 17.3 to 21.6% for venous occlusion and 27.3 to 32.3% for postural plethysmography. A relation was not found between results for the two methods, suggesting that they explore different phenomena. Variability of venous physiology parameters is marked, modulations being due to general or local factors, the former acting on both legs simultaneously: exterior temperature, neurocardiovascular physiology, digestion, stress, relaxation. Factors can have their effects reduced by differential study of the two limbs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
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↗
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↗
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↗
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↗