Two-frequency impedance plethysmograph: real and imaginary parts

1990 ◽  
Vol 28 (1) ◽  
pp. 38-42 ◽  
Author(s):  
A. Lozano ◽  
J. Rosell ◽  
R. Pallás-Areny
Keyword(s):  
Impedance Plethysmograph

Respiratory monitoring with a new impedance plethysmograph

Anaesthesia ◽  
1986 ◽  
Vol 41 (11) ◽  
pp. 1139-1142 ◽  
Author(s):  
S. Hoffman ◽  
R. Jedeikin ◽  
D. Atlas
Keyword(s):  
Respiratory Monitoring ◽  
Impedance Plethysmograph

COMPUTERIZED IMPEDANCE PLETHYSMOGRAPHY, A NEW PLETHYSMOGRAPHIC METHOD TO DETECT DEEP VEIN THROMBOSIS

1987 ◽  
Author(s):  
P Prandoni ◽  
M Vigo ◽  
M V Huisman ◽  
J Jonker ◽  
H R Büller ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Discriminant Analysis ◽  
Impedance Plethysmography ◽  
Single Test ◽  
Vein Thrombosis ◽  
Non Invasive ◽  
Impedance Plethysmograph ◽  
Deep Vein ◽  
Center Study ◽  
Sensitive Method

Since the clinical diagnosis of deep vein thrombosis (DVT) is unreliable, several invasive and non-invasive methods have been developed recently. Of these, impedance plethysmography (IPG) is a widely employed technique based on measurement of changes in blood volume produced by temporary obstruction. IPG has been shovn in large prospective studies in symptomatic patients to be a safe and effective alternative to contrast venography, if used either in combination with 1251-fibrinogen legscanning or serially as a single test. Currently available impedance plethysmographs are limited by several technical and operational problems. Therefore, a new computerized impedance plethysmograph (CIP) was developed, having the following characteristics: portability, battery operated and fully automated. A prospective two-center study in 299 consecutive outpatients was done to compare the efficacy of CIP vs. venography in patients with symptomatic DVT. Using a blind design i.e. care was taken to insure that CIP and venography were performed and interpreted independently. The results in patients without venography proven thrombosis and those with proximal vein thrombosis were subjected to a discriminant analysis producing a line of best discrimination between normal and proximal vein thrombosis. In 14 patients it was not possible to obtain an adequate CIP tracing. 12 patients were not entered because of refusal to undergo venography and 15 patients were excluded from analysis because of poor opacification of the proximal veins. On the basis of discriminant analysis 138 of the CIP results were classified as normal and 120 as abnormal. 175 patients were normal on venography and 83 had proximal thrombosis. The sensitivity of CIP for proximal vein thrombosis was thus 95% while the speci-+ ficity was 77%. It is concluded that computerized impedance plethysmography is a potentially sensitive method to detect proximal vein thrombosis in patients with clinically suspected deep vein thrombosis.

Calibrated impedance plethysmograph

1980 ◽  
Vol 239 (2) ◽  
pp. H283-H288
Author(s):  
M. R. Yablonski ◽  
J. M. Van De Water ◽  
B. E. Mount ◽  
E. D. Laska ◽  
R. B. Indech
Keyword(s):  
Electrical Impedance ◽  
Correlation Coefficients ◽  
Pulse Frequency ◽  
Volume Measurement ◽  
Frequency Variation ◽  
Blood Resistivity ◽  
Impedance Model ◽  
Electrode Distance ◽  
Pulse Volume ◽  
Impedance Plethysmograph

The accuracy of quantitative pulse-volume measurement with a calibrated electrical impedance plethysmograph was determined on a laboratory limb-segment model. Changes in electrical impedance detected via a tetraprolar electode configuration were related to pulse-volume changes by the parallel-impedance model described by Nyboer et al. (The Impedance Plethysmograph: An Electrical Volume Recorder. Natl. Res. Council, Comm. Aviation Med. 149, 1943). The instrument employed in this study calculated pulse volume assuming two standard conditions: distance between voltage electrodes, l, is 15 cm, and resistivitiy of blood, rho b, is 150 omega x cm. The effects of varying tissue and blood resistivity, pulse frequency, and electrode distance were investigated. Measurements under three ionically distinct conditions gave an overall accuracy of 96.6% with correlation coefficients of 0.99 for each condition. Measurement accuracy was maintained with a pulse-frequency variation in the range of 15-150 pulses/min and with application of correction factors for electrode distance and blood resistivity other than the standard values.

scholarly journals Automatic digital-analog impedance plethysmograph

2016 ◽  
Vol 705 ◽  
pp. 012007 ◽  
Author(s):  
C B Goy ◽  
K A Mauro ◽  
L M Yanicelli ◽  
N F Parodi ◽  
M A Gómez López ◽  
...  
Keyword(s):  
Impedance Plethysmograph

Dual-channel self-balancing impedance plethysmograph for vascular studies

1981 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
J. S. Arenson ◽  
R. S. C. Cobbold ◽  
K. W. Johnston
Keyword(s):  
Vascular Studies ◽  
Dual Channel ◽  
Impedance Plethysmograph

How to Measure Changes in Oedema in Patients with Chronic Venous Ulcers?

1992 ◽  
Vol 7 (1) ◽  
pp. 31-35 ◽  
Author(s):  
M. D. Barnes ◽  
R. Mani ◽  
D. F. Barrett ◽  
J. E. White
Keyword(s):  
Health Service ◽  
Lower Limb ◽  
Venous Insufficiency ◽  
Bed Rest ◽  
Impedance Plethysmography ◽  
Limb Volume ◽  
Water Displacement ◽  
Venous Ulceration ◽  
Venous Ulcers ◽  
Impedance Plethysmograph

objective: To assess changes in limb volume and oedema in Patients admitted to hospital for treatment of venous ulceration. Design: Prospective study in thirteen patients. Setting: Health Service teaching hospital. Patients: Thirteen patients with venous ulceration for 2 years. Interventions: Patients were admitted to hospital for bed-rest and lower limb elevation for a period of 24 hours Main outcome measures: Limb volume was measured by water displacement and impedance plethysmography. Results: During limb elevation there was a mean reduction limb volume of 524 mls (95% CI 377–671 mls) after 24 hours of bedrest. This corresponded with a reduction in impedance measured by the impedance plethysmograph of 19–0 ohms (95% CI 24.3 to 15.6 ohms). Conclusion: Measurement of the lower limb volume by water displacement and by impedance plethysmography are likely to be useful methods in the investigation of Patients with chronic venous insufficiency.

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