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PubMed2000

Detection of inspiratory flow limitation during sleep by computer assisted respiratory inductive plethysmography.

The potential of respiratory inductive plethysmography (RIP) to detect inspiratory flow limitation during sleep was investigated. Sixteen sleep apnoea patients underwent polysomnography. Airflow by a flowmeter attached to a nasal mask, oesophageal and mask pressure were recorded along with calibrated RIP. Presence of inspiratory flow limitation was defined by constant or decreasing flow without pressure dependence throughout significant portions of inspiration, its absence by a linear or mildly alinear pressure:airflow relationship. Based on this standard, three of various computerized RIP derived parameters, with highest performance to detect flow limitation, were identified. They were combined to an inspiratory flow limitation, (IFL)-Index(RIP), which was validated prospectively in another 10 sleep apnoea patients. RIP derived fractional inspiratory time, peak to mean inspiratory flow ratio, and ribcage contribution to tidal volume had the highest accuracy to detect flow limitation (area under the receiver operating characteristic (ROC) curves 0.81, 0.76, 0.76, respectively, 160 comparisons). Prospective validation revealed an area under the ROC curve for the IFL-Index(RIP) to detect flow limitation of 0.89 (95% confidence interval 0.85 to 0.93, 200 comparisons) with sensitivity and specificity at the point of equality of 80%. It is concluded that inspiratory flow limitation may be assessed by computer assisted analysis of respiratory inductive plethysmography derived breathing patterns with clinically acceptable accuracy.

Adult↗
PubMed2004

Child-specific thoracic gas volume prediction equations for air-displacement plethysmography.

OBJECTIVE: To develop child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography in 6- to 17-year-old children. RESEARCH METHODS AND PROCEDURES: Study 1 developed TGV prediction equations using anthropometric variables after completing a measured TGV and air-displacement plethysmography test in 224 healthy boys and girls (11.2 +/- 3.2 years, 45.3 +/- 18.7 kg, 149.9 +/- 18.5 cm). Study 2 cross-validated the prediction equations in a separate cohort of 62 healthy boys and girls (11.2 +/- 3.4 years, 44.2 +/- 15.3 kg, 149.4 +/- 19.3 cm). RESULTS: In Study 1 (development of TGV prediction equations), the quadratic relationship using height as the independent variable and the measured TGV as the dependent variable yielded the highest adjusted R(2) and the lowest SE of estimate in both genders, thus producing the following prediction equations: TGV = 0.00056 x H(2) - 0.12422 x H + 8.15194 (boys) and TGV = 0.00044 x H(2) - 0.09220 x H + 6.00305 (girls). In Study 2 (cross-validation), no significant difference between the predicted and measured TGVs (-0.018 +/- 0.377 liters) was observed. The regression between the measured TGV and the predicted TGV yielded a slope and intercept that did not significantly differ from the line of identity. Prediction accuracy was good as indicated by a high R(2) (0.862) and low SE of estimate (0.369 liters). DISCUSSION: The new child-specific TGV prediction equations accurately, precisely, and without bias estimated the actual TGV of 6- to 17-year-old children.

Adolescent↗
PubMed1999

Body composition in children and adults by air displacement plethysmography.

OBJECTIVES: Air displacement plethysmography (ADP) may provide a partial alternative to body density (Bd) and therefore body composition measurement compared to conventional hydrodensitometry (Hd) in children. As there are no evaluation studies of ADP in children, this study had a two-fold objective: to compare Bd estimates by ADP and Hd; and to compare fat estimates by both ADP and Hd to fat estimates by another reference method, dual energy X-ray absorptiometry (DXA). SETTING: Obesity Research Center, St. Luke's/Roosevelt Hospital, New York, USA. SUBJECTS: One hundred and twenty subjects (66 females/54 males) who ranged in age from 6-86 y and in body mass index (BMI, kg/m2) from 14.1-40.0 kg/m2 met study entry criteria. STUDY DESIGN: Cross-sectional study of healthy children (age < or = 19 y) and adult group for comparison to earlier studies. Each subject completed ADP, Hd, and DXA studies on the same day. Only subjects with subjectively-judged successful Hd studies were entered into the study cohort. RESULTS: There was a high correlation between Bd by ADP and Hd (Bd Hd = 0.11 + 0.896 x Bd ADP; r = 0.93, SEE = 0.008 g/cm3, P < 0.0001), although the regression line slope and intercept differed significantly from 1 and 0, respectively. Additional analyses localized a small-magnitude Bd bias in the child (n = 48) subgroup. Both ADP and Hd %fat estimates were highly correlated (r > 0.9, P < 0.0001) with %fat by DXA in child and adult subgroups. Bland-Altman analyses revealed no significant %fat bias by either ADP or Hd vs DXA in either children or adults, although a bias trend (P = 0.11) was detected in the child subgroup. CONCLUSION: With additional refinements, the air displacement plethysmography system has the potential of providing an accurate and practical method of quantifying body fat in children as it now does in adults.

Absorptiometry, Photon↗
PubMed2003

Evaluation of factors determining the precision of body composition measurements by air displacement plethysmography.

OBJECTIVES: To investigate methodological precision of air displacement plethysmography for assessment of body composition in a heterogenous sample of adults. DESIGN: Accuracy of volume measurements by air displacement plethysmography (ADP) for a range of known volumes was ascertained. Repeated measurements of body volume, lung volume, and derived body composition using the BODPOD measurement system were performed. Influence of surface area estimation on ADP measurement was investigated as a possible source of variation. SETTING: Clinical Nutrition Laboratory, School of Health & Sports Science, University of North London, London, UK. SUBJECTS: One hundred and two healthy subjects (57 women, 45 men) who ranged in age between 16 and 55 y and in BMI (kg/m(2)) between 17.8 and 41.9. STUDY DESIGN: Cross-sectional study of healthy adults for comparison with previous studies. Repeat measurements of raw body volume, lung volume and % body fat (BF) by ADP were all performed on the same day. RESULTS: From the range of known volumes a marked increase in the CV and a significantly greater measurement error were found at volumes below 40 l (P=0.04). Repeat measurements of raw body volume in human subjects resulted in a technical error equivalent to 0.8% BF. There was no significant difference found between measured and predicted lung volume and the 95% confidence interval for difference was only 0.3% BF. Repeat measurements of lung volume in our subset resulted in a technical error equivalent to 0.5% BF. Although body surface area estimation only accounted for variation in % BF of 0.1%, the extent of variation appeared to be governed by leanness (P<0.001). CONCLUSIONS: Although ADP retains excellent precision, in practice, repeat measurements of ADP should be performed whenever possible to allow for erroneous volume measurement within one procedure. Protocols for ADP measurement should be created with an awareness of those factors, which may affect measurements. SPONSORSHIPS: This study was supported by the University of North London Diversity & Development Fund.

Adolescent↗
PubMed2003

Influence of leg position and environmental temperature on segmental volume expansion during venous occlusion plethysmography.

Blood flow determinations by venous occlusion plethysmography applying the strain-gauge technique are frequently used. A problem with the strain-gauge technique is that the relationship between venous volume and transmural pressure is not linear and, furthermore, changes with the sympathetic tone. The present study tests the hypothesis that these factors lead to a redistribution of venous blood, which may impair the accuracy of the technique. The relative volume expansion rates of four leg segments were studied with the leg in different positions and at disparate temperatures, thereby inducing varying venous pressures and sympathetic tone ( n =6). With elevated leg and relaxed veins (at 50 degrees C), the distal thigh showed a relatively low expansion rate (25.8+/-4.5 ml.min(-1).l(-1)), whereas values in the calf segments were higher (34.5-39.0 ml.min(-1).l(-1)). With lower initial transmural pressure, calf segments can increase their volume much more during occlusion compared with the distal thigh. In a higher transmural pressure region (lowered leg), the difference in compliance between limb segments is less. In this case, compliance and volume expansion rate was higher in the distal thigh (14.2, 13.5 and 22.2 ml.min(-1).l(-1) at 10, 20 and 50 degrees C respectively) than in the calf segments (for the distal calf: 6.4, 7.7 and 16.2 ml.min(-1).l(-1) respectively). There was a significant interaction ( P <0.001) between temperature and leg position, indicating a higher degree of sympathetic vasoactivity in the calf. It is concluded that blood flow determination by strain-gauge plethysmography is less accurate, due to a potential redistribution of the venous blood. Therefore possible influences of variations in sympathetic tone and venous pressure must be considered even in intra-individual comparisons, especially in interventional studies.

Adult↗
PubMed2004

Can lymphatic drainage be measured non-invasively in human limbs, using plethysmography?

There is always rapid volume restitution of the accumulated interstitial fluid after a VCP (venous congestion plethysmography) protocol. It has been suggested that backward extrapolation of the relationship between applied hydrostatic pressure and fluid filtration may give a measure of tissue J (vL) (lymph flow); if so, this could be of immense value in pathophysiological investigations. We hypothesized that the congestion pressure decrease following the VCP protocol might be the stimulus for activating the observed rapid interstitial fluid removal mechanism. We investigated this hypothesis by using a cumulative small step VCP protocol to a maximum arterial diastolic pressure, followed by a mirror image of step pressure decreases. The increases and decreases in cuff pressure produced capillary filtration capacities that were not significantly different from one another [(3.8+/-1.0) x 10(-3) and (3.7+/-1.2) x 10(-3) ml x 100 ml(-1) x min(-1) x mmHg(-1) respectively]. However, we did observe a significant 3-fold increase in estimated lymph flow between the up and 'mirror' down protocol. Moreover, the calculated supine control value, reflecting interstitial fluid removal ( J (vL)), of 0.03+/-0.03 ml x 100 ml(-1) x min(-1) was within the range of lymph flows in human limbs described by other workers, as was the 3-fold increase to 0.09+/-0.03 ml x 100 ml(-1) x min(-1) following the release of the venous congestion. These results support the notion that strain-gauge plethysmography might provide a non-invasive means of assessing peripheral lymph flow in human limbs.

Adult↗
PubMed2001

Assessment of forearm vasodilator responses to acetylcholine and albuterol by strain gauge plethysmography: reproducibility and influence of strain gauge placement.

AIMS: To determine the within-subject reproducibility of the forearm blood flow response to acetylcholine and the beta2-adrenoceptor agonist albuterol as measured by strain gauge plethysmography. To examine the influence of strain gauge placement on these responses. METHODS: Vasodilator response to brachial artery infusion of drugs was assessed by strain gauge plethysmography in six healthy men on each of three occasions separated by 1 week. Strain gauges were placed on both arms at the point of maximum diameter. On the infused arm two further gauges were positioned approximately 4 cm proximal and distal to the middle gauge. RESULTS: Within-subject coefficients of variation (WCV) of absolute blood flow responses for each dose of acetylcholine (7.5, 15, 30 micrograms min(-1)) ranged from 24% to 27%, as compared with WCV values of 41% to 62% for the percentage changes in blood flow ratio (infused : noninfused arm). For albuterol (0.3, 1, 3 micrograms min(-1)) the corresponding WCV values were 16% to 19% and 30% to 55% for absolute blood flow and percentage change in blood flow ratio, respectively. WCV for the area under dose-response curve (AUC) for absolute blood flow was 18% and 13% for acetylcholine and albuterol, respectively. Vasodilator responses were similar whether recorded proximal to or at the point of maximal forearm circumference. Distal strain gauge misplacement underestimated responses and the difference was greater for acetylcholine than for albuterol. CONCLUSIONS: In healthy men, the WCV for responses expressed as absolute blood flow, to acetylcholine and albuterol ranges from 16% to 27%.

Acetylcholine↗
PubMed2001

Forearm blood flow measurements using computerized R-wave triggered strain-gauge venous occlusion plethysmography: unilateral vs. bilateral measurements.

The human forearm is a well established model to study local vascular reactivity in humans in vivo, using strain-gauge venous occlusion plethysmography to measure blood flow and changes in blood flow in the forearm. To reduce the intra-individual variability of the forearm blood flow (FBF), it has been advocated that simultaneous measurements of contralateral forearm blood flow is obligatory. Therefore, the use of the calculated forearm ratio (FR) is recommended instead of using the actual FBF. In the present study we compared the intra-individual variability of forearm blood flow measurements and the forearm ratio, by using computerized R-wave triggered strain-gauge venous occlusion plethysmography, to test if bilateral expression of measurements is better than unilateral. Results were obtained in eight volunteers. Intra-arterial infused sodium nitroprusside induced a dose dependent increase in forearm blood flow and a dose dependent increase in the calculated forearm ratio. Intra-arterial infused norepinephrine induced a dose dependent decrease in forearm blood flow and a dose dependent decrease in the calculated forearm ratio. The differences between the variation coefficients of the forearm blood flow measurements and the calculated forearm ratio were different. These results support our hypothesis that by using a computerized, R-wave triggered system for unilateral forearm blood flow measurement is a more reliable outcome than the calculated forearm ratio derived from bilateral measurements.

Adult↗
PubMed1999

Reproducibility of resting peripheral blood flow using strain gauge plethysmography.

The purpose of this study was to examine the intra-tester and inter-tester reliability of strain gauge plethysmography (SGP) using the Hokanson EC-5R plethysmograph among three investigators. An arterial inflow test was performed by each of the investigators on fifteen college-aged volunteers at the forearm and calf sites. Intra-tester reliability was assessed by analyzing three serial measurements obtained at both sites. Intertester reliability was assessed in two ways: first, by having the three investigators obtain and analyze their own recordings, and, second, by having all three investigators (Testers 1, 2, and 3) analyze SGP recordings obtained by the most experienced investigator (Tester 1). The mean coefficient of variation (CV) for the intra-tester analysis was similar at the forearm (4.9%) and calf (4.0%) sites. The inter-tester analysis revealed that there were no significant differences among the three testers at either site when investigators obtained and analyzed their own waveforms. The CV calculated from the means of the three investigators was greater at the forearm site (10.7%) than at the calf site (2.5%). Similarly, when Testers 2 and 3 analyzed Tester 1's waveforms there were no significant differences found among testers at either site and the CV was less than when each investigator obtained his/her own waveforms. Strain gauge plethysmography blood flow measures obtained by experienced testers, under controlled laboratory conditions, are reproducible. The small variability in blood flow that exists is more attributable to variability in the acquisition of the waveforms than in the analysis of the waveforms.

Adult↗
PubMed1986

Serial impedance plethysmography for suspected deep venous thrombosis in outpatients. The Amsterdam General Practitioner Study.

Diagnosis of deep venous thrombosis by clinical signs and symptoms is unreliable, but contrast venography is relatively expensive and invasive. We therefore evaluated the use of impedance plethysmography as a noninvasive alternative in 426 consecutive outpatients with clinically suspected acute deep venous thrombosis. Four sequential impedance plethysmograms were obtained on days 1, 2, 5, and 10 of the study. In 289 patients (68 percent), the results of all four studies were normal, and these patients were not treated with anticoagulants. One of these patients may have had a minor pulmonary embolus during the 10-day study period. During a six-month follow-up of all patients, none of the 289 patients whose plethysmograms were normal died of venous thromboembolism or presented with suspected pulmonary embolism. In 137 patients (32 percent), the impedance plethysmograms were abnormal; 117 (85 percent) had the abnormal results on their first test, and 20 (15 percent) had them on subsequent tests. All patients with abnormal plethysmograms also underwent contrast venography, which confirmed the diagnosis of deep venous thrombosis in 92 percent. We conclude that the diagnostic accuracy of repeated impedance plethysmography compares favorably with that of venography and that the technique is a safe and effective noninvasive approach to the diagnosis and care of outpatients with clinically suspected acute deep venous thrombosis.

Adult↗
PubMed1987

Air-plethysmography and the effect of elastic compression on venous hemodynamics of the leg.

Leg volume changes during exercise have been measured in absolute units (milliliters) by means of a new method of air-plethysmography. Venous volume (VV), venous filling time, and venous filling index on standing from the recumbent position, ejected volume (EV) and ejection fraction (EF = EV x 100/VV) with one tiptoe movement, and residual volume (RV) and residual volume fraction (RVF = RV x 100/VV) after 10 tiptoe movements were measured in normal limbs, limbs with superficial venous incompetence, and limbs with deep venous disease. The same measurements were repeated with a graduated medium compression stocking in limbs with SVI and graduated high compression stockings in limbs with DVD. Ambulatory venous pressure was measured at the same time, with a needle in a vein in the foot. The results indicate that this method of air-plethysmography is not only of diagnostic value but offers a new and unique technique to assess and study the hemodynamic effects of different forms of elastic compression. The lower ambulatory venous pressure, produced by the elastic compression, was the result of a reduction in reflux and an improvement in the calf muscle ejecting ability during rhythmic exercise.

Adult↗
PubMed1998

Ultrasound-Doppler technique for monitoring blood flow in the brachial artery compared with occlusion plethysmography of the forearm.

Blood flow changes in the brachial artery of seven subjects during and after submaximal static handgrip contractions were measured by duplex Doppler ultrasound technique. These measurements were compared with the results of occlusion plethysmography, measured immediately (2-3 heartbeats) after. For the combined data from all measurements, a common calibration line could be drawn (linear regression, r=0.92). The flow measurements from the two methods were tested by a four-way analysis of variance and there was no significant difference between the methods during (static) exercise, indicating acceptable coherence. Occlusion plethysmography may well be used for monitoring forearm blood flow during conditions of static exercise. In addition, the cuff occlusion pressure of the plethysmograph (50 mmHg) decreased the blood flow of the brachial artery by approximately 28% as measured by duplex Doppler ultrasound.

Adult↗
PubMed1998

Comparison of air displacement plethysmography with dual-energy X-ray absorptiometry and 3 field methods for estimating body composition in middle-aged men.

This study was designed to compare air displacement plethysmography with dual-energy X-ray absorptiometry (DXA) and 3 other field methods for estimation of body composition. Subjects were 62 healthy, white men aged 37.6+/-2.9 y (weight: 81.8+/-11.3 kg; height: 171.5+/-4.9 cm). Body composition was also assessed by using body mass index, single-frequency bioelectrical impedance analysis, multi-frequency bioelectrical impedance spectroscopy, and the skinfold-thickness equations of Jackson and Pollock and Durnin and Womersley. Percentage body fat (%BF) with the plethysmograph was 23.4+/-7.0 and with DXA was 26.0+/-7.4. The 2.6% mean difference was significant (P< 0.05). Total error was 3.7%BF. As assessed by multiple regression analysis, %BF with the plethysmograph, age, weight, and height yielded a DXA-adjusted R2 value of 89.5% fat and an SEE of 2.4% fat. All other models had higher SEEs and lower adjusted R2 values: 4.3% and 66.5% for body mass index, 3.3% and 79.8% for bioelectrical impedance analysis, 3.6% and 76.2% for bioelectrical impedance spectroscopy, 3.7% and 74.55% for the equations of Jackson and Pollock, and 3.9% and 71.6% for the equations of Durnin and Womersley, respectively. The plethysmograph also predicted fat mass and fat-free mass more accurately than all other models, with a lower SEE and higher adjusted R2 value. In conclusion, although %BF was systematically underestimated, body composition was closely estimated with air displacement plethysmography in middle-aged men.

Absorptiometry, Photon↗
PubMed2005

A new clinical method for the assessment of penile endothelial function using the flow mediated dilation with plethysmography technique.

PURPOSE: Penile endothelial function (EnF) is 1 of the major factors involved in the pathophysiology of erectile dysfunction. EnF assessment could offer crucial information on the etiology and degree of severity of cavernosal vascular pathology. In the present study we propose a new technique for the evaluation of penile EnF and test its applicability using strain gauge plethysmography. MATERIALS AND METHODS: A total of 23 healthy subjects (13 younger and 10 older than 40 years) with no history of erectile dysfunction were studied. The flow mediated dilation technique was applied to the arm and penis in both age groups for the assessment of EnF. Baseline blood flow and the sequential flow recordings after rapid cessation of 5 minutes of ischemia were obtained in both organs. RESULTS: Baseline flow in the penis was significantly higher (approximately 3-fold) than that in the forearm and was not affected by age in either organ. Both measures of penile EnF, ie area under the flow-time curve (AUC) and maximal flow obtained after ischemia were significantly lower in the older group compared to the younger group (p <0.01 and p <0.02, respectively). Individual penile AUC and maximal flow were significantly correlated with age (r = 0.55, p <0.01 and r = 0.50, p <0.02, respectively). Finally a positive, significant correlation existed between penile and forearm AUC (p <0.05, r = 0.48). CONCLUSIONS: The implementation of the flow mediated dilation technique using mercury strain gauge plethysmography is simple and applicable for the assessment of penile EnF. Endothelial function parameters in the penis were found to correlate with those in the forearm, thus support for the validity of the technique is given. Further strength for the validity of this procedure in the penis comes from the comparison between the forearm and penis, and the relation to subject age.

Adult↗
PubMed2004

Respiratory inductance plethysmography used to diagnose bilateral diaphragmatic paralysis: a case report.

OBJECTIVE: To report the use of respiratory inductance plethysmography in the diagnosis and management for a case of bilateral diaphragmatic paralysis after repeated sternotomies in a 23-month-old child. DESIGN: Case report. SETTING: A 15-bed pediatric cardiothoracic intensive care unit in an academic children's hospital. INTERVENTIONS: The patient could not be weaned from the ventilator after a repeat sternotomy for pulmonary artery reconstruction. Pulmonary function test results were within normal limits, and plain film radiography, ultrasonography, and fluoroscopy were unable to establish a definitive diagnosis. Evaluation of thoracoabdominal synchrony was undertaken using respiratory inductance plethysmography (RespiTrace). The work of breathing was assessed using esophageal manometry to obtain the pressure-rate product. RESULTS: During spontaneous breathing, complete thoracoabdominal asynchrony was noted, with clockwise Konno-Mead loops and associated phase angles of nearly 180 degrees. The pressure-rate product was 120 cm H(2)O/min, indicating elevated work of breathing. The pressure-rate product decreased dramatically, as indicated by measurement and observation, in response to increased levels of continuous positive airway pressure. CONCLUSIONS: The diagnosis of bilateral diaphragmatic paralysis can be confirmed by measurement of thoracoabdominal synchrony. Therapeutic and diagnostic application of continuous positive airway pressure may predict response to diaphragmatic plication. Controlled trials comparing measurement of thoracoabdominal synchrony with standard methods for the early diagnosis of diaphragmatic paralysis are needed.

Diaphragm↗
PubMed1992

Comparison of digital blood pressure, plethysmography, and the modified Allen's test as means of evaluating the collateral circulation to the hand.

The collateral circulation to the hand was evaluated on 70 hands of healthy volunteers. Comparisons were made between the results of the modified Allen's test alone and the Allen's test combined with either plethysmography or digital blood pressure. The modified Allen's test requires patient cooperation and the results can be subjective. Plethysmography does not require patient cooperation and produces a signal that varies directly with flow; however, this is not a quantifiable signal. Digital blood pressure (measured by the 2300 Finapres noninvasive blood pressure monitor, Ohmeda, Englewood, CO, USA) also requires no patient cooperation. The values produced are of clinical value and reproducible. Both the plethysmograph and digital blood pressure monitors were able to demonstrate the dominant arterial vessel of the hand. The digital blood pressure monitor produces an objective recordable numerical value, an accepted clinical parameter, and it does not require patient cooperation. The use of a digital blood pressure monitor may prove to be an acceptable alternative to the traditional Allen's test.

Blood Pressure↗
PubMed2006

Plethysmography and impulse oscillometry assessment of tiotropium and ipratropium bromide; a randomized, double-blind, placebo-controlled, cross-over study in healthy subjects.

AIMS: Spirometry, plethysmography and impulse oscillometry (IOS) measure different aspects of lung function. These methods have not been compared for their ability to assess long- and short-acting anticholinergic agents. We therefore performed a double-blind, placebo-controlled, four-way cross-over study in 30 healthy subjects. METHODS: Single doses of tiotropium bromide (Tio) 54 and 18 mcg, ipratropium bromide (IB) 40 mcg and placebo were administered. Specific conductance (sGaw), total lung capacity (TLC), inspiratory capacity (IC) and residual volume (RV) were measured using plethysmography, while IOS measured resistance (R5-25) and reactance (RF and X5). Pulmonary function was measured for 26 h post dose. RESULTS: Tio caused significant improvements in sGaw, forced expiratory voume in 1 s (FEV(1)), maximum mid-expiratory flow (MMEF) and R5-R25 at time points up to 26 h, with no clear differences between doses. IB improved the same parameters, but only up to 8 h. The weighted mean change (0-24 h) caused by Tio 54 mcg compared with placebo for FEV(1) was 240 ml (95% confidence interval 180, 300), while for sGaw the ratio of geometric means (Tio compared with placebo) was 1.35 (1.28, 1.41). Neither drug caused consistent statistically significant changes in RF, forced vital capacity, TLC or IC over 26 h. RV was significantly improved from 8 to 24 h by Tio 54 mcg only. CONCLUSIONS: In addition to spirometry, IOS resistance measurements and sGaw can distinguish between the effects of long- and shortacting anticholinergic effects in healthy subjects.

Adult↗
PubMedDate not supplied

Use of strain gauge plethysmography in the study of varicocele.

The clinical significance of strain gauge plethysmography in pampiniform plexus pathology has been explored, with the assumption that there should be some analogy with lower limb venous conditions in which this examination gives valuable results. The first findings seem to confirm that strain gauge plethysmography affords, in varicocele, some reliable evaluations on venous drainage insufficiency, capacity and resiliency of spermatic venous bed as well as on functional results of surgical treatment.

Humans↗