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At least 577 records · Page 32Linked to original sources
PubMed1980

Fibrin degradation products and impedance plethysmography. Measurements in the diagnosis of acute deep vein thrombosis.

Measurement of fibrin degradation products (FDP) was evaluated in 152 consecutive patients referred because diagnosis of deep vein thrombosis (DVT) was suspected. All patients underwent impedance plethysmography (IPG), and venograms were obtained in 59. Sensitivity and specificity of FDP measurement, using venography as the standard, was 88% and 66%, respectively. Sensitivity and specificity of IPG was 77% and 79%, respectively. Specificity of the two tests combined, when both yielded abnormal results, was 93%. Patients were classified as (1) normal, (2) abnormal, or (3) equivocal on the basis of IPG. A significant difference in mean FDP concentration was found between groups 1 and 2 and groups 2 and 3. An overall correlation was found between degree of abnormality on IPG and FDP concentration. A quantitative determination of FDP is a practical and reliable screening test for DVT and, when used in conjunction with IPG, improves both sensitivity and specificity of the latter.

Adult↗
PubMed1979

[Comparison of the oscillatory measurement of airway resistance with plethysmography and spirometry in juvenile patients].

In 78 children (age 4 to 17 years, height 102 to 179 cm) with and without clinical signs of airway obstruction, spirometric and plethysmographic measurements were compared with the forced oscillation method for determination of resistance to breathing (Ros). Ros was measured with a recently developed apparatus (Siregnost FD5. Siemens) and showed a close correlation with resistance (r = 0.84; n = 78). The spirometric values did not, however, exhibit a definite relationship to Ros. This study demonstrates that airway obstruction in children can be equally well estimated by oscillatory and plethysmographic techniques. Compared with plethysmography, determination of Ros has the particular advantage of being better tolerated by young subjects.

Adolescent↗
PubMedDate not supplied

[The vasodilating effect of chlorthalidone in mild hypertension evaluated by impedance venous plethysmography].

Thirty hypertensive outpatients of both sexes having diastolic blood pressure below 110 mmHg were included in a randomized trial. Their mean age was 50.4 +/- 8.6 years. After a two-week placebo period, the patients were treated with chlorthalidone in a single daily dose of 25 or 12.5 mg over the one-month period, and the next month the alternative dose (i.e. 12.5 or 25 mg) was administered. Changes in vascular reactivity were measured by occlusive plethysmography (mercury strain-gauge) at the end of the placebo period, and then post the first and second month of therapy. All the observed parameters, i.e. rest flow (RF), peak flow (PF), venous capacity (VC), and maximal venous outflow (MVO) increased with 25 mg of chlorthalidone, and similar findings were registered when a dose of 12.5 mg was given. There was a significant increase in venous capacity of both groups (from 2.6 to 3.2 and from 3.0 to 3.4 ml/100/min) and in peak flow of the group that was on 25 mg of chlorthalidone as the first dose (from 18.6 to 23.9 ml/100ml/min). Both doses had similar antihypertensive effect. It is concluded that antihypertensive effect of chlorthalidone is partly due to changes in vascular reactivity in the sense of vasodilation which is more prominent at the venous side of the blood flow, Low-dosed chlorthalidone is equipotent in antihypertensive efficiency, its side effects are rare, and the cost of therapy is by far the lowest.

Chlorthalidone↗
PubMed1994

[Determination of the optimal atrioventricular timing by impedance plethysmography in patients with cardiac pacing; correlations with left ventricular filling].

The stroke volume (SV) was measured by the change in the impedance in thirteen patients with dual chamber pacemakers at different atrioventricular delay (AVD) intervals: 31 to 219 ms or 75 to 220 ms. The mitral inflow was also recorded by Doppler echocardiography at each AVD with measurement of the duration of mitral flow (MFD) and the velocity time integral (VTI). All thirteen patients were studied in the DDD mode; in addition, 5 patients were studied in the atrial sensing ventricular stimulation VDD mode. The SV measurement by impedance plethysmography was reproducible with an average variability of 3.5%: the optimal AVD was determined by this method in 11 patients with DDD and 4 patients with VDD pacing: in 3 patients (2 in DDD and 1 in VDD mode) 2 optimal AVD were obtained. The optimal AVD was 123 +/- 31 ms (63 to 156 ms) in DDD mode and 91 +/- 17 ms (63 to 110 ms) in VDD mode. The analysis of left ventricular filling showed that changes in AVD led to similar changes in mitral VTI. The MFD increased as the AVD was shortened to a constant value at the optimal AVD. In all patients, the optimal AVD was obtained when the MFD became maximal and constant. Measurement of MFD is a simple and rapid means of assessing optimal AVD at rest in patients with dual chamber pacing systems.

Adult↗
PubMed1994

[Air plethysmography in the diagnosis of primary venous insufficiency of lower extremities].

Through the assessment 101 limbs of 77 subjects by air plethysmography (AP), we studied the method of AP test and the values of various indices in diagnosis of primary venous insufficiency (PVI). Venous filling index (VFI) was found valuable to quantitate the venous reflux with its value beyond the threshold of 5 ml/sec. It has a potential value to assess the effect of operations on PVI, such as valvuloplasty aiming to abolish venous reflux. Ejection fraction (EF) was found to be abnormal with its value less than 40%. It may be used to evaluate the function of calf pump quantitatively, predict the ulcer formation, and help make a decision of surgery timely. The comprehensive analysis of VFI, EF, RVF (residual volume fraction) and AVP (ambulatory venous pressure) indicated that there seems to be different types of PVI: type 1, low ejection (low EF) high venous reflux (high VFI); type 2, high ejection low venous reflux; type 3, low ejection low venous reflux. This new classification may impose some on the selection of adequate therapies, which will be further investigated.

Air↗
PubMed1994

[Determination of reference temperatures for a cold test in digital plethysmography].

BACKGROUND: The purpose of this study was to determine optimal warm and cold temperatures for performance of a cold test. METHODS: Thirty-six healthy volunteers (22 women and 14 men; mean age 40, 94 years, range: 20-58) were included in the study. Plethysmographic signal amplitudes were evaluated at different temperatures (47, 45, 43, 40, 35, 20, 15, 13, 11 and 9 degrees C) under standardized conditions, using digital strain-gauge plethysmographic (Perivein Janssen). Reproducibility was assessed by repetition in the same subject of six digital plethysmography signal measurements at 45 degrees C performed at different times and days. Clinical tolerance was estimated according to an analogue scale. RESULTS: Maximal warm amplitude was obtained at 45 degrees C and maximal vasoconstriction at 13 degrees C. The thermal test was well tolerated for the temperature range between 11 and 45 degrees C. Reproducibility of the measurements was satisfactory. CONCLUSIONS: 45 degrees C is the non-nociceptive reproducible vasoparalyzing reference temperature, allowing measurement of maximal digital circulatory capacities. 11 degrees C should be adopted as the optimal vasoconstriction temperature for performance of a cold test.

Adult↗
PubMedDate not supplied

[Pulmonary capacity and volume, forced expiratory flow measured by whole body plethysmography in acute pancreatitis: experimental study in rats].

Up to 70% of the patients with acute pancreatitis suffer a sort of pulmonary dysfunction. Twenty-nine rats with pancreatitis induced by 2.5% taurocholic and solution have been studied by whole body plethysmography in order to evaluate pulmonary volumes and expiratory flows. They were divided into three groups: a sham operation control group-10 rats,a two pancreatitis group-10 rats and eight hours pancreatitis group-9 rats. The results showed a significant decrease of expiratory reserve volumes and forced vital capacity (FVC) and also a significant increase of expiratory flow in the 2 and 8 hours pancreatitis groups. These findings indicate a restrictive pneumopathy.

Acute Disease↗
PubMed1994

Upper extremity impedance plethysmography in patients with venous access devices.

Central venous access devices (VADs) are often associated with thrombotic obstruction of the axillary-subclavian venous system. To explore the accuracy of impedance plethysmography (IPG) in identifying this complication we performed IPG on 35 adult cancer patients before their VADs were placed and approximately 6 weeks later. At the time of the second IPG the patients also underwent contrast venography of the axillary-subclavian system. The venograms revealed partial venous obstruction in 12 patients (34%) and complete obstruction in two (5.7%). Although the IPG results from venographically normal and abnormal patients overlapped extensively, mean measurements of venous outflow were significantly lower in the patient population with abnormal venograms (P = 0.052 for Vo; P = 0.0036 for Vo/Vc). In our hands, therefore, upper extremity IPG cannot be used to make clinical decisions about individual patients with VADs, but it can distinguish venographically normal and abnormal populations.

Adult↗
PubMedDate not supplied

Chest wall motion in neonates utilizing respiratory inductive plethysmography.

After calibration, respiratory inductive plethysmography can accurately measure breathing patterns noninvasively by transmitting ribcage and abdomen compartment changes caused by ventilation through oscillator circuitry. We measured the breathing pattern of nine quietly awake healthy newborn infants and assessed components reflecting asynchrony, paradoxic motion, and overall phasic relations between ribcage and abdomen compartments. Breathing pattern data (mean +/- SD) on 136 total tidal volume (Vt) breaths revealed: Vt, 14.4 +/- 3.40 ml; frequency, 52.1 +/- 11.5 beats/min; ribcage contribution to Vt, 32.2% +/- 13.4%; maximum compartmental amplitude/Vt, 1.01 +/- 0.01; phase angle, 13.2 +/- 9.50 degrees; inspiratory asynchrony index, 0.26 +/- 0.20 ml2/ml; expiratory asynchrony index, 0.42 +/- 0.3 ml2/ml; and average asynchrony index, 0.34 +/- 0.20 ml2/ml. Results demonstrated a high degree of synchrony between ribcage and abdomen movement during quietly awake breathing. Outward motion of the abdomen preceded that of the ribcage for almost every measured breath.

Abdomen↗
PubMed1994

Reevaluation of the sensitivity of impedance plethysmography for the detection of proximal deep vein thrombosis.

BACKGROUND: To reevaluate the sensitivity of impedance plethysmography (IPG) for proximal deep vein thrombosis (DVT) and to establish a relationship between the location and size of thrombi and the results of IPG. DESIGN: Prospective cohort study. METHODS: One hundred thirty-two consecutive patients with clinically suspected DVT underwent IPG testing and most (n = 118) underwent contrast-enhanced venography; in 14 patients, venous ultrasonography was performed and demonstrated definitive proximal DVT in which the size and extent of the thrombus could be delineated. All patients with dubious or normal ultrasound results underwent contrast-enhanced venography. All tests were performed and test results were interpreted without knowledge of the results of the other tests. Patients were considered to have proximal DVT if this was demonstrated on venography or ultrasound, calf DVT if this was demonstrated on venography, or no DVT if venography yielded normal findings. The sensitivity and specificity of IPG for DVT were calculated. RESULTS: Of the 132 patients, 40 (30%) had proximal DVT, seven (5%) had calf DVT, and 85 (64%) had no DVT. The sensitivity of IPG for proximal DVT was 65% and the specificity was 93%. Of the proximal vein thrombi, IPG detected three (23%) of 13 that involved the popliteal vein but not the superficial femoral vein and 23 (85%) of 27 proximal vein thrombi that involved the superficial femoral vein. CONCLUSIONS: Our study demonstrated that the sensitivity of IPG for proximal DVT at our center is only 65%, a figure that is much lower than those reported in earlier studies from our institution. We hypothesize that because of a change in referral practice, an increased proportion of patients with less severe symptoms are now referred to our center than in the past. These patients have thrombi that are smaller, less likely to be occlusive, and therefore less likely to yield abnormal IPG findings.

Adult↗
PubMed1993

Can air plethysmography accurately identify upper extremity deep venous thrombosis?

PURPOSE: Air plethysmography (APG) is an established, noninvasive means of evaluating lower extremity venous outflow. METHODS: To determine whether APG could identify deep venous thrombosis (DVT) of the upper extremity, we measured the percentage of venous outflow in the first second (maximum venous outflow [MVO]) of four groups of arms: (1) normal volunteers (no previous central vein catheters), (2) the affected, (3) the unaffected arms of the patients with DVT (proven by venography or duplex scanning), and (4) hospital patients (no previous central vein catheters). RESULTS: The results of an analysis of variance were as follows: the mean MVO (%) of the affected arms of patients with DVT, 29.4 +/- 2.6, was significantly less than their unaffected arms, 55.3 +/- 3.9, hospital controls, 64.3 +/- 2.2, and normal volunteers, 64.2 +/- 0.9 (p < 0.05). In addition, the unaffected arms differed significantly from all groups (p < 0.05). An MVO of 45% was 2 SD below the mean MVO of the normal volunteer group. Two unaffected arms of the patients with DVT were below 45%, whereas only one affected arm of the patients with DVT was above 45% (45.6%). Therefore a comparison of the distribution of the MVO values revealed virtually no overlap of the affected arms of the patients with DVT with the other three groups. CONCLUSIONS: We conclude that APG clearly discriminated arms with documented DVT from controls and is a highly accurate means of identifying upper extremity DVT.

Adult↗
PubMed1993

Features of thrombi and diagnostic accuracy of impedance plethysmography in symptomatic and asymptomatic deep vein thrombosis.

Impedance plethysmography (IPG) has high sensitivity and specificity in patients with symptomatic deep vein thrombosis (DVT) while it fails to detect asymptomatic DVT. The aim of this study was to determine whether the features of thrombi such as location, size and occlusiveness could explain the different accuracy of IPG in symptomatic and asymptomatic DVT patients. One-hundred and seventeen consecutive outpatients with a clinical suspicion of DVT and 246 consecutive patients undergoing hip surgery were admitted to the study. In symptomatic patients IPG was performed on the day of referral, followed by venography, while in asymptomatic patients IPG was performed as a surveillance programme, followed by bilateral venography. A venography proved DVT was observed in 37% of the symptomatic patients and 34% of the asymptomatic limbs. A significantly higher proportion of proximal DVTs was found in symptomatic patients than in asymptomatic patients (78% vs 46%; p = 0.001). The mean Marder score, taken as an index of thrombus size, was significantly higher in symptomatic patients than in asymptomatic patients (19.0 vs 9.6; p = 0.0001). A significantly higher proportion of occlusive DVTs was observed in symptomatic than in asymptomatic patients (69% vs 36%; p = 0.001). We conclude that the unsatisfactory diagnostic accuracy of IPG in asymptomatic DVT is due to the high prevalence of distal, small and non occlusive thrombi. Such thrombi are unlikely to cause a critical obstruction of the venous outflow and therefore to produce a positive IPG.

Dermatan Sulfate↗
PubMed1993

[Microvascular monitoring using mercury in silastic strain gauge plethysmography (MSG)].

Mercury in silastic strain gauge plethysmography (MSG) is a noninvasive method for assessing microvascular parameters in peripheral limbs. MSG allows measurement of capillary filtration coefficient (Kf), isovolumetric venous pressure (Pvi), venous pressure (Pv) and arterial inflow (Qa) into the limb, respectively. We used MSG in combination with invasive monitoring techniques (pulmonary artery flotation catheters and arterial catheters) to study 36 critically ill patients in either hemorrhagic or septic shock. We observed marked increases in Pvi in both patient groups which correlated with outcome. On admission, both groups showed elevated values for Pvi, survivors 37.7 +/- 2.6, nonsurvivors 33.7 +/- 3.5 mm Hg (mean +/- SEM) when compared with a control group of young healthy students (22.1 +/- 0.82 mm Hg). Survivors showed a decrease in Pvi to 27.3 +/- 1.7 mm Hg, whereas in nonsurvivors Pvi increased to 39.5 +/- 3.0 at the last measurement taken. The changes in Pvi depended on the resuscitation regime used. On admission, patients requiring only fluid replacement (F) had a lower Pvi (31.3 +/- 2.9 mm Hg) than patients needing inotropic support with dobutamine (D, Pvi = 38.2 +/- 2.4 mm Hg) to fulfill our therapeutic goals (DO2 > 550 ml.min-1 x m-2, VO2 > 150 ml.min-1 x m-2 and mixed venous lactate < 1.5 mmol/l). After treatment Pvi did not change significantly in the F group (31.3 +/- 1.8), the D group however showed a significant decrease in Pvi to 25.4 +/- 2.42, which did not differ from the normal value. We regard Pvi as an indicator of insufficient microvascular flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1977

Thermal problems in plethysmography and pressure/volume recording.

Where volume changes are recorded as the concomitant changes in pressure, modern, fast-responding pressure transducers might record not only the pressure changes due to volume changes in the measured object but also the heat of compression, showing itself as an overshoot or hysteresis phenomenon in the calibration curves. Introduction of an effective heat sink (e.g. copper mesh) within the air space in the plethysmograph might absorb this heat and thereby diminish the overshoot phenomena. The effect is not of practical importance in classical venous occlusion plethysmography where rapid changes only contribute to a smaller part of the total volume change during venous occlusion. When rapid changes, as in volume pulse recordings, are to be evaluated, the effect must be taken into consideration and should be reduced.

Blood Pressure Determination↗
PubMed1995

Comparison of the accuracy of impedance plethysmography and compression ultrasonography in outpatients with clinically suspected deep vein thrombosis. A two centre paired-design prospective trial.

Impedance plethysmography (IPG) and compression ultrasonography (CUS) have been reported to be highly accurate for the diagnosis of deep vein thrombosis (DVT) in symptomatic patients. In many centres CUS has become the method of choice. However, direct comparisons of the accuracy of IPG to CUS have not been performed. To determine the test of choice we performed a two centre prospective comparison of IPG and CUS, with venography, and determined how the size and distribution of thrombi influenced the accuracy of each test. 495 symptomatic outpatients with suspected DVT had evaluable venograms. The prevalence of DVT was 27% (130/495), 84% (109) of which were proximal. The sensitivity of IPG and CUS for proximal vein thrombosis was 77% and 90% respectively (p = .002). The specificity of IPG was 93% whereas the specificity of CUS was 98% (p = 0.04). There were significant differences in accuracy between the two centres as a consequence of differences in the size and location of thrombi The majority of proximal thrombi not detected by IPG and CUS involved less than 5 cm of the distal half of the popliteal vein and most of these thrombi occurred in one centre. Exclusion of these thrombi from the analysis increases the sensitivity of CUS to 99% (86/87) and IPG to 91% (72/79), for proximal thrombi (P = .019). The positive predictive value of CUS was strongly influenced by the number of abnormal venous segments (three sites were examined); 100% (80/80) if two or three sites were abnormal, but only 68% if a single site was involved. We conclude that: 1) CUS is more accurate than the IPG for the diagnosis of DVT in symptomatic outpatients, and this relationship holds true regardless of the size or location of the DVT, 2) the sensitivities of IPG and CUS are much lower for small proximal DVT, and 3) confirmatory venography is warranted if the abnormality with CUS is limited to one venous segment.

Ambulatory Care↗
PubMedDate not supplied

Acceleration plethysmography to evaluate aging effect in cardiovascular system. Using new criteria of four wave patterns.

UNLABELLED: Acceleration plethysmography (APG) uses the second derivative of the waveform of the digital photoplethysmography to stabilize the baseline and to separate components of the waveform more clearly than the first derivative. The purposes of this study were 1) to investigate the association between APG and aging, using our new criteria of four patterns and 2) to test the clinical usefulness of APG for the prediction of the level of atherosclerosis. The examined subjects were 82 males and 308 females aged 30-69 years. Plethysmograms were recorded in the sitting position. We compared the distribution of four patterns of APG by age group and analyzed the predictor of changing waveforms. We also analyzed the association between wave patterns and the risk factors, i.e. total cholesterol (TC), high density lipoprotein cholesterol, systolic blood pressure, diastolic blood pressure, body mass index, and current smoking status. THE RESULTS: -categorized four wave patterns were significantly associated with aging; -pulse pressure (PP), body height and sex influenced waveforms of APG independently of age; and -categorized wave patterns were associated with high serum TC among risk factors for atherosclerosis. Those results suggest that APG reflects the arterial wall properties which change with age and might predict the level of atherosclerosis. To provide further guidance for determining appropriate clinical interpretations of APG, it is required to consider the effects of PP, body height and sex. We conclude that simply categorized wave patterns of APG could be a useful noninvasive tool to evaluate aging in cardiovascular system.

Adult↗
PubMed1997

[Usefulness of measurement of blood flow by RI plethysmography].

We have developed the RI plethysmography, and have applied it to ordinary clinic diagnosis and the evaluation of treatment. The subjects were 58 cases (39 cases of the obstruction of the peripheral blood circulation: ASO 24 cases, TAO 4 cases and arterial sclerotic change 11 cases; the non-abnormal control was 19 cases). The clinical benefit of this method was evaluated. In the cases with 1 and 2 degrees of Fontaine's classification and ASO and TAO, the blood flow of legs measured by our method significantly decreased in association with symptoms and angiographic findings. This method is suitable to the determination of angiography and evaluation of the effect of treatment.

Adult↗
PubMedDate not supplied

[Strain-gauge plethysmography in angiopathies caused by vibrant tools].

The authors compare the results obtained from the strain gauge plethysmography on 79 patients affected by vibrating machines angiopathology with a group of 20 others non exposed to vibrations. The results, analyzed according to the microcirculation vision, lead the authors to suppose that the damage caused by vibrating instruments is revealed at the capillary bed trophic exchange level.

Adult↗