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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↗
PubMed1982

Assessment of time-volume and flow-volume components of forced vital capacity. Measurement with spirometry, body plethysmography and respiratory inductive plethysmography in nonsmokers and smokers.

The purpose of this investigation was to assess the effectiveness of the time-volume and flow-volume components of the forced vital capacity measured by simultaneous spirometry, respiratory inductive plethysmography, and body plethysmography in detecting small airway disease. Spirometry measured the exit of gas from the lungs, whereas body plethysmography measured both the exit of gas and alveolar gas compression. Respiratory inductive plethysmography, which reflected change in thoracic volume, provided semi-quantitative data f both gas exit and alveolar gas compression which generally lay between spirometry and body plethysmography. In nine nonsmokers and 12 smokers (six with small airway disease as defined by abnormal closing volumes and alveolar uniformity), analysis of forced vital capacity revealed that the only test which differentiated nonsmokers from smokers was the higher spirometric estimation of maximum expiratory flow measured at 25 percent VC in nonsmokers. Combining flow measure at the mouth with volume referenced to change in alveolar gas volume as measured by body or respiratory inductive plethysmography did not differentiate nonsmokers from smokers. Moment analysis performed of forced vital capacity with all of the three devices did not distinguish nonsmokers from smokers. The data in this study and a review of other investigations indicate that the time-volume and flow-volume components of the forced vital capacity on air breathing are not very sensitive in detecting early lung disease in smokers.

Adolescent↗
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↗
PubMed1995

Plethysmography with optoelectronic sensors: comparison with mercury strain gauge plethysmography.

The study and follow-up of certain physiological adaptations in microgravity, particularly vascular and venous ones, require the use of reliable equipment that yields results well correlated with data provided by equipment usually used in clinical examinations. The purpose of the present study was to evaluate the reproducibility of results obtained using a new type of plethysmography, plethysmography with optoelectronic sensors or volometry, and to verify whether these results correlate with those yielded by mercury strain gauge plethysmography. The plethysmograph is a device which permits measuring limb volume by means of an infra-red light transmitter-receiver system that calculates cross-sectional areas at 220 successive points of a given limb segment. Calf venous capacity (calf volume measured after 50 mm Hg venous occlusion in the thigh) was measured on 27 subjects using volometry and mercury strain gauge plethysmography used as reference method. Results showed a good correlation (r = 0.8, p < 0.001) and a statistically identical reproducibility between the two methods even though venous capacity measurements obtained using these two techniques were not superimposable because they did not use the same model for limb volume measurements. Volometry therefore appears to be a technique of interest for the future, to monitor vascular and muscular physiological parameters in astronauts during long-term microgravity exposure.

Adult↗
PubMed1982

Assessment of density dependent flow-volume parameters in nonsmokers and smokers. Measurement with spirometry, body plethysmography and respiratory inductive plethysmography.

The purpose of this investigation was to assess the density-dependent flow-volume components of the forced vital capacity using simultaneous spirometry, respiratory inductive plethysmography, and body plethysmography in the detection of small airway disease. The forced vital capacity was measured during air, helium-oxygen and sulfur-hexafluoride breathing to provide a range of gas density influences. Combining flow measured at the mouth with volume referenced to change in alveolar gas volume as measured by body or respiratory inductive plethysmography during helium-oxygen breathing accentuated the differences between nonsmokers and smokers because of the variable degree of alveolar gas compression occurring over the second half of FVC. The volume of isoflow obtained when comparing the helium and oxygen mixture to air also effectively separated nonsmokers from smokers. The utilization of the high density gas mixture, sulfur hexafluoride-oxygen during the FVC maneuver did not provide useful diagnostic information. Therefore, density-dependent flow-volume information using helium as a test gas alone or compared to air with a variety of analyses is a good approach to detection of early lung disease in smokers.

Adolescent↗
PubMed1984

Venous occlusive RN plethysmography: comparison with electrical admittance plethysmography.

A venous occlusion plethysmography using radionuclide (RN) was introduced for the measurement of the limb blood flow. This technique, called RN plethysmography, can be carried out in a subject who has been previously administered RN intravenously for the routine angiographic examination. The blood flow is calculated from the initial slope of the RN count rate change (RN accumulation curve) due to venous occlusion. In this study, this method was compared with electrical admittance plethysmography. The blood flow values determined by these two methods correlated well with each other.

Biomedical Engineering↗
PubMed1982

Comparison of electrical field plethysmography with electrical impedance plethysmography.

As a means for assessing cardiac function, electrical field plethysmography (EFP) has been shown to have some features quite different from electrical impedance plethysmography (EIP). Here the two techniques are compared by using the two systems simultaneously on a subject and also with independent use in different electrode configurations. The results conform with the view that EIP is related primarily to volumetric changes of the aorta, whereas EFP is affected predominantly by changes in cardiac dimensions and orientation. Because of this difference, the standard time differential formula used for EIP is not applicable for the computation of cardiac output from the EFP waveforms. An alternative method of computation based on the amplitude of the EFP waveform is suggested.

Cardiac Output↗
PubMed1981

[Strain-gauge-plethysmography in consideration with finger venous occlusion plethysmography. A critical view of its methods and diagnostic possibilities (author's transl)].

The strain-gauge plethysmography, which has already successfully been applied to the calf and forearm the past years, has now, after extensive technical perfection, also been applied to the finger. Particular importance has to be paid to the selection of the measurement gauge and the cuff. Developed was a method to measure correct fit of the finger gauge to promote nearly a 100% correct registration of finger circumference. In order to get a proportionate distribution of the pressure inside the cuff; cuffs with a deep-drawn relief on the inside are used. The different temperatures on the hand, essential for functional diagnostic, are produced by an electronically regulated water-bath.

Body Temperature Regulation↗
PubMed1998

A simple clinical model for the diagnosis of deep-vein thrombosis combined with impedance plethysmography: potential for an improvement in the diagnostic process.

OBJECTIVES: We recently demonstrated the utility of a clinical model combined with ultrasonography to assist the diagnostic approach in patients with suspected deep-vein thrombosis (DVT). In this study we also sought to demonstrate that the model is useful with impedance plethysmography, a less accurate and less utilized diagnostic test. The original clinical model is slightly cumbersome to use; thus at the completion of the study we attempted to develop a simpler scoring system with a goal of maintaining accuracy. DESIGN: An open, nonrandomized, multicentre trial. SETTING: Three centres, two in Canada, and one in Italy. SUBJECTS: Ambulatory patients with suspected deep-vein thrombosis. INTERVENTIONS: All patients were assessed clinically to determine the probability for deep-vein thrombosis prior to performing impedance plethysmography and venography. We compared the accuracy of impedance plethysmography between the three pretest probability categories of high, moderate and low. All of the above were performed and interpreted by independent observers. When the study was completed, we revised the clinical model by first performing a simple regression analysis then a multiple logistic regression analysis; a scoring system was devised using the latter. RESULTS: Impedance plethysmography is significantly more sensitive and less specific for all DVT in patients with high pretest probability for deep-vein thrombosis (P = 0.001). The post- test probability (positive predictive value) for deep-vein thrombosis with an abnormal impedance plethysmography result was significantly different (P = 0.0001) between the three pretest probability categories. Multiple regression analysis has provided a new model with only nine variables and a simple scoring system. The retrospective application of the revised clinical model, which is simpler to use, suggests it will provide similar results as the original clinical model when combined with impedance plethysmography. The combination of impedance plethysmography and the clinical model suggests patients are likely to have false positive results if they have a low or moderate pretest probability for deep-vein thrombosis and false negative results if the pretest probability is high. The combination of a low pretest probability and a normal impedance plethysmography result may exclude the need for serial testing, and represented more than 50% of our patient population. CONCLUSIONS: The use of the clinical model in conjunction with impedance plethysmography would decrease the number of false positive and negative diagnoses and could markedly decrease the need for serial impedance plethysmography. Combining the clinical model with impedance plethysmography could overcome the fact that impedance plethysmography is clearly less accurate than venous ultrasound imaging. The use of the revised clinical model may increase acceptability and utility, but prospective testing is required before widespread use.

Diagnosis, Differential↗
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↗
PubMed1995

Pressure sensor plethysmography: a method for assessment of respiratory motion in children.

Noncalibrated respiratory inductance plethysmography has been used to measure respiratory function by calculation of the phase angle and, more recently, by determination of the ratio of each time to reach peak tidal expiratory flow to total expiratory time (TPEF/TE). Since TPEF/TE is known to be decreased in airway obstruction when derived from flow signals obtained by a pneumotachograph, we wanted to develop an alternative method to measure rib cage and abdominal respiratory movements. For this purpose, we used two pressure sensors attached to the skin above the umbilicus and in the right medioclavicular line at the fourth intercostal space: "pressure sensor plethysmography". We tested the ability of this method to assess thoracoabdominal asynchrony and TPEF/TE by comparison with respiratory inductance plethysmographic and pneumotachographic measurements in 30 children, aged 1-12 yrs, with airway obstruction. The mean difference (95% confidence interval (95% CI)) between phase angles obtained by respiratory inductance plethysmography and pressure sensor plethysmography was only -5.8 degrees (range -18.0 to +6.4 degrees). Similarly, all methods used to measure TPEF/TE agreed well: mean differences (95% CI) between pneumotachographic and respiratory inductance plethysmographic, pneumotachographic and pressure sensor plethysmographic, and respiratory inductance plethysmographic and pressure sensor plethysmographic measurements of TPEF/TE were +0.01 (range -0.05 to +0.06), -0.03 (-0.09 to +0.03) and -0.03 (-0.10 to +0.04), respectively. We conclude that pressure sensor plethysmography is a simple and noninvasive method, and suitable to measure thoracoabdominal asynchrony and TPEF/TE ratios as well as respiratory inductance plethysmography and pneumotachography.

Abdomen↗