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PubMed2006

Impulse oscillometry vs. body plethysmography in assessing respiratory resistance in children.

In 334 children aged 5-18 years, we compared the results of plethysmographic measurements of airway resistance (Raw) with oscillometric (impulse oscillometry; IOS) assessment of respiratory properties of the respiratory system (resistance (R) at 5, 20, and 35 Hz). All three resistances correlated significantly with plethysmographic Raw, and the strongest correlation was seen for R5 (r = 0.64). R5, R20, and R35 were significantly greater than Raw in the whole group. In the group of children with obstruction (FEV(1)%FVC below lower limit of normal), R5 was still greater than Raw, while R20 and R35 were not. The Bland-Altman analysis comparing plethysmographic measurements with oscillometric R5 revealed a significant difference between Raw and R5 in the whole group, which disappeared in the group of obstructed patients. Oscillometric assessment of resistive properties of the respiratory system of the lung requires less patient cooperation than does plethysmography. As the results of measurements using oscillometric R5 are similar to those obtained by plethysmography, IOS may be useful in diagnosing children with obstructive respiratory diseases.

Adolescent↗
PubMed1987

Noninvasive measurement of arterial blood pressure and elastic properties using photoelectric plethysmography technique.

The objective of this paper is to review our developed method for measuring noninvasively the arterial blood pressure as well as the mechanical properties of the vascular system in a thin portion of the biological segment such as human fingers or small animal extremities like rat tails and rabbit forelegs. This measurement is based on a principle called the 'volume-oscillometric method'. During the gradual change in cuff pressure, the amplitude of consecutive arterial volume pulsations associated with pulse pressure shows change characteristically due to the nonlinearity of arterial pressure-volume(P-V) relation. Arterial pressure can be accurately determined by detecting this characteristic change in the amplitude, while the arterial elastic properties such as P-V relationship and volume elastic modulus can be noninvasively obtained as a function of arterial transmural pressure, provided that the arterial volume changes are quantitatively determined during this pressure measurement. The validity and accuracy of this pressure and elasticity measurement with photoelectric plethysmography technique for detecting arterial volume changes are clearly demonstrated on the in vitro and in vivo experiments. Considering the simplicity and practicability of this measurement using the photoelectric plethysmography, we present a new portable instrument for the long-term ambulatory monitoring of indirect arterial pressure and a handy fully-automatic instrument for the noninvasive measurement of arterial elastic properties, and a few examples obtained by each instrument are also described.

Animals↗
PubMed1975

Strain gauge plethysmography for blood flow measurements in the legs of children.

The arterial resting flow, the arterial peak flow after 3 minutes of circulatory arrest to the leg, and the venous emptying rate were studied by strain gauge plethysmography in the calves of 85 children between 3 and 16 years of age. Most of the children had heart disease; therefore the values obtained can be regarded as reference values only for this type of patient.--The reproducibility of the results of the flow measurements was favourable and equal to that found in the examination of adults and of children using water-filled plethysmographs. --All of the flow functions investigated were significantly higher in the younger children and--but not always significantly--higher in boys than in girls. There was no difference between sides as regards arterial flow, whereas the venous emptying rate was significantly lower in the left calf. --Strain gauge plethysmography is recommended for assessment of circulatory complications after vascular catheterization in children aged 4 years or older.

Adolescent↗
PubMedDate not supplied

Noninvasive, quantitative determination of muscle blood flow in man by a combination of venous-occlusion plethysmography and computed tomography.

Because of the lack of non-invasive methods for measuring muscle blood flow, quantitative investigations of blood flow in the skeletal muscle of hypertensive subjects are rare. We therefore developed a new method for the determination of muscle blood flow noninvasively and quantitatively by a combination of computed tomography and venous occlusion plethysmography (strain-gauge method). At two sites on one forearm (p = site of the largest diameter, d = 1 cm proximal to the epicondyle lat.) the volumes of tissues [Vt = total volume, VM = muscle volume, VSk = bone volume, VR = residual volume = Vt - (VM + VSk)] were determined by computed tomograms and total forearm blood flow (Fp and Fd, respectively in ml/100 ml tissue x min) measured by strain-gauge plethysmography. After correcting for the bone volume at the different sites, Fp and Fd were transformed into the absolute influx rates of blood volume (Qp and Qd). From Qp and Qd and the different tissue volumes, the muscle blood flow (FM in ml/100 ml muscle x min) could be calculated: (formula; see text) Results thus derived were compared with data from the literature Cooper et al. (17). At rest there was neither a significant difference in Fp (own results: 3.62 +/- 1.67, Cooper: 3.25 +/- 1.42 ml/100 ml tissue x min, means +/- S.D.) nor in FM (4.08 +/- 2.07 and 3.66 +/- 1.57 ml/100 ml muscle x min, respectively), however, Fp and FM were significantly different (p less than 0.05). In the mean, FM was 13% greater than Fp, range: -40 to +38% (Cooper 15%, range: -17 to +43%). The individual difference could not be predicted by any of the parameters. Testing the procedure by means of a pharmacological agent (clonidine) with known effects on muscle blood flow (no change) and skin blood flow (decrease) revealed the correct reproduction of this hemodynamic pattern with our method. The usual identification of total with muscle blood flow would have led to false conclusions.

Adult↗
PubMed1981

[Impedance plethysmography: measurements of volume changes of human limbs caused by capillary filtration (author's transl)].

The idea of this paper is to examine, after a discussion of the theoretical foundations, to what extent impedance plethysmography enables us to measure changes in the volume of the human extremities caused by capillary fluid filtration. Possibilities of error shown up in this paper - e. g., resistance of the skin, phase shift between current and voltage, the influence of specific resistance, dependence on temperature - partially confine the applicability of impedance plethysmography to comparative relative measurements. In these cases and in full view of the possibilities of error this method offers the advantage of absolutely pressureless measurement and the opportunity to extend this procedure to days.

Capillaries↗
PubMed1996

Effects of carvedilol and atenolol on arterial pulse curves (plethysmography) and finger temperature after hand cooling.

OBJECTIVE: In a double-blind, parallel study, the effects of 25 mg carvedilol and 50 mg atenolol on peripheral finger circulation and arterial pulse curve configuration were compared. METHODS: Healthy volunteers (n = 17) were examined at baseline and for 15 min after 60 s of hand cooling in ice-water. Finger temperature and digital plethysmography were recorded each minute from the cooled and the control hands. Measurements were also made before and 2 h after drug administration. RESULTS: Blood pressure declined from 120/86 to 108/74 mm Hg after atenolol (n = 9), and from 122/88 to 108/73 mm Hg after carvedilol (n = 8). In both groups, baseline finger temperature increased slightly after drug, and a more rapid rise in finger temperature was observed after cooling. There was no group difference in the drug effect on finger temperature, except in the first few minutes after cooling, when temperature recovery was greater after carvedilol. Carvedilol reduced the vasoconstrictor response to local cooling (digital plethysmography), compared both to the value before drug and after atenolol. At rest, carvedilol changed the pulse curves (control hand) towards vasodilatation and high compliance, expressed as a mean change in the relative height of the dicrotic notch of -10.3% versus 0.0% after atenolol. CONCLUSION: Future studies should clarify whether the vasoactive profile of carvedilol may translate into reduced occurrence of cold hands and feet amongst patients treated for hypertension.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Role of radioisotope penile plethysmography in the evaluation of penile hemodynamics in impotent patients.

Nineteen impotent patients were included in the study. Radioisotope penile plethysmography using technetium-99m-labelled RBC was performed on each patient before and after intracavernosal injection of prostaglandin E1 (PGE1) for quantitating the penile hemodynamic change. The peak penile blood flow (PPF) and penile blood volume change (dPV) were evaluated. The results revealed that (a) the PPF values (mean 2.24 +/- 1.38 ml/min) of all patients were lower than that of the patients with no arterial changes previously reported, and (b) there was good correlation between PPF and dPV (r = 0.75). We conclude that quantitative radioisotope penile plethysmography coupled with intracavernosal injection of PGE1 is a valuable method for the objective evaluation of the penile erectile response of impotent patients, and that the PPF values of the impotent patients with arterial insufficiency might be a reliable parameter of penile volume change.

Alprostadil↗
PubMed2002

Theoretical and practical considerations in the application of whole body plethysmography to sleep research.

The sleep-wake state has a profound influence on many, perhaps most, aspects of normal physiology and is strongly implicated in the mediation (or remediation) of impaired health and performance. Many sleep disorders stem from abnormal respiratory anatomy or sleep-induced changes in respiratory control, underscoring the need for research into the effects of the sleep-wake state on respiratory control processes. Whole body plethysmography is being increasingly used to study respiration in freely behaving animals, and is especially well suited to studies of sleeping animals and human subjects. The method is simple in principle, but care is required in its application to ensure reliable results, and there are circumstances in which it is an inappropriate technique. This review describes the main advantages, pitfalls, and limitations inherent in the use of whole body plethysmography for non-invasive measurement of lung ventilation and metabolic rate in sleeping animals. Sources of potential error, and ways of avoiding such errors, are discussed, with reference to studies involving animal models of sleep-related breathing disorders.

Animals↗
PubMed2001

Air plethysmography: an alternative method for assessing peripheral circulatory adaptations during spaceflights.

A new approach to the study of peripheral vascular hemodynamics in microgravity was initiated by designing an alternative methodology: air plethysmography (AP). This is the only technique that enables the quantification of vascular hemodynamics from gross measurements performed on the limbs. This paper reports a description of the device and of the measurement protocol. A comparative study showed that AP yields results that are well correlated, although not in agreement, with those obtained by means of the reference method in the laboratory (mercury strain gauge plethysmography, MSGP; for venous capacity, correlation coefficient r = 0.8, P < 0.0001, limits of agreement--0.9 ml.100 ml-1 and 1.4 ml.100 ml-1; for arterial flow index, correlation coefficient r = 0.7, P < 0.0006, limits of agreements -20.4 ml.min-1 and 37.2 ml.min-1; for half-emptying time, correlation coefficient r = 0.9, P < 0.0001, limits of agreement -0.88 s and 0.77 s), and that are characterized by good reproducibility (coefficient of variation in general lower than 12%). Preliminary findings during spaceflight, on board the Mir Space Station, yielded data that is expected to improve our knowledge of vascular deconditioning in conditions of weightlessness.

Adaptation, Physiological↗
PubMed2003

Feasibility of air plethysmography (BOD POD) in morbid obesity: a pilot study.

The assessment of body composition (BC) in morbidly obese patients is a difficult procedure. Air-displacement plethysmography (ADP), which measures body density, is a very promising technique for BC assessment in health and disease. However, there are very few data about the feasibility of applying ADP on morbidly obese patients, which theoretically could be affected by large body size and difficulty in lung volume measurements. The main aim of this pilot study was to evaluate the feasibility of using ADP for BC assessment in morbidly obese patients. We studied nine subjects (6 males and 3 females) who had a mean age (+/-SD) of 47.0+/-13.5 years and body mass index (BMI) of 46.6+/-7.7 kg/m(2) (range 36.4-58.8). All patients could fit into the instrument chamber and perform the manoeuvre for pulmonary plethysmography. Mean lung volume was 3.9+/-1.2 l and mean percent body fat was 53.1+/-6.6 (range 46.0-67.5). These results indicate that ADP appears to be suitable for patients with BMI over 40 kg/m(2) and produces realistic BC data.

Adipose Tissue↗
PubMed1988

Penile plethysmography on impotent men using vacuum constrictor devices.

Vacuum constrictor devices achieve an erection-like state of the penis by means of a clear plastic cylinder, a vacuum pump, and a constrictor ring. Although these devices are noninvasive compared with penile injections and implants, they have been used less often in clinical practice. Part of the hesitancy to prescribe these devices has been related to the lack of published data concerning the effects of constriction on penile blood flow. In this report, we utilized penile plethysmography to estimate penile blood flow on 51 men before, during, and after the use of the constrictor ring. All patients demonstrated a 70-75 percent decline in the amplitude of the pulse-volume curve during constriction, but continuous blood flow was maintained in each case. Within sixty seconds after removal of the ring, the amplitude returned to baseline values for all men, including 12 patients with a penile brachial index of less than 0.7. Among 33 patients, there was evidence of a transient increase of amplitude following constriction, which was consistent with a postischemic hyperemia. These findings suggest normal penile blood flow, and indicate that the use of constrictor rings may be safe for patients with these tracings. Penile plethysmography appears to be a useful technique to help with patient selection and constrictor ring fit. Follow-up tracings probably should be scheduled at periodic intervals for men utilizing these rings and devices.

Adult↗
PubMed1989

Assessment of erectogenic drugs by numeric plethysmography.

A method of assessment of the erection in man, using numeric penile plethysmography, is presented. The data concerning the sensor, the electronic circuit, and the computer interfacing with an IBM PC are described. As a validation of this method, apomorphine (0.009 mg/kg) was tested in a double-blind, placebo-controlled study, carried out in healthy volunteers. Apomorphine induced an erection starting, as a mean, at the fourth minute postinjection. The treatment increased the penis volume without any other stimulation (p = 0.0008) and potentiated the physiologic response induced by visual erotic stimulation (p = 0.0012). The limits of plethysmography are discussed in reference to rigidimetry.

Adult↗
PubMed2005

Forced oscillations, interrupter technique and body plethysmography in the preschool child.

The interrupter technique, forced oscillation and plethysmography have been increasingly used to monitor early childhood respiratory diseases over the past 30 years. The techniques are based on different principles but generally yield concordant information. Data from all three techniques indicate significant airway response to bronchodilators in healthy and asthmatic preschool children. The interrupter technique is useful but yields little more than a single value of respiratory resistance. Forced oscillation and plethysmography may provide additional information relevant to the mechanisms of airway obstruction, provided the methodological artefacts are accounted for and corrected.

Airway Resistance↗
PubMed1998

Calculation of plasma concentrations of intra-arterially infused compounds in forearm plethysmography.

OBJECTIVE: Forearm blood flow plethysmography is a widely accepted in vivo technique for pharmacologic and functional studies in peripheral resistance vessels and veins. Pharmacological effects on forearm blood flow (FBF) are usually expressed by means of dose-response relationships. This approach does not consider the influence of variations in FBF on the actual plasma concentrations of compounds infused, and is less suitable for quantitative comparison of the pharmacologic characteristics of different compounds. The aim of this study was to validate an equation to estimate the plasma concentrations of intra-arterially infused compounds. This was done at different levels of FBF, using an indicator dilution technique with constant rate infusions of indocyanine green (ICG) and inulin. METHODS: ICG (0.5 mg/min) and insulin (5 mg/min) were infused into the brachial artery in the presence of sodium nitroprusside (10 ng/kg/min; to obtain high FBF), vehicle (0.9% saline; for intermediate FBF), and methoxamine (1 microgram/kg/min; for low FBF), FBF was measured using venous occlusion plethysmography in six healthy male volunteers. Plasma concentrations of the indicators, measured in venous blood samples, were compared with the calculated values. RESULTS: Excellent correspondence was observed between calculated and measured plasma concentrations for both ICG and inulin. Venous plasma concentrations of ICG (> or = 95% protein binding) reached steady-state within four min independent of FBF. Alternatively, the time required for venous plasma concentrations of inulin (not bound to protein) to reach steady-state appeared dependent on FBF. CONCLUSION: Total plasma concentrations of intra-arterially infused drugs can be appropriately estimated at the level of the arterioles by the proposed equation.

Adult↗
PubMed1984

Diagnosis of deep-vein thrombosis: comparison of clinical evaluation, ultrasound, plethysmography, and venoscan with X-ray venogram.

In 50 patients with suspected deep-vein thrombosis the diagnostic accuracy of standardised clinical examination, doppler ultrasound, impedance plethysmography, and technetium-99m-labelled-fibrinogen scintigraphy (venoscan) was compared with that of X-ray venography. Physical examination was the least accurate method. Impedance plethysmography, venoscan, and ultrasound had accuracies of 65%, 80%, and 82%, respectively. The initial X-ray venogram report had an accuracy of 90% compared with the interpretation of two experienced radiologists. The venoscan was equivocal in 32% of patients, and in the remaining patients the accuracy was 97%. Objective methods of investigation are essential for diagnosing deep-vein thrombosis. Of those tested, the X-ray venogram was the only investigation suitable for definitive diagnosis. The venoscan may have a role as a screening procedure, to be followed by X-ray venography in patients with equivocal venoscan results.

Adolescent↗
PubMed2001

The role of preoperative radial artery ultrasound and digital plethysmography prior to coronary artery bypass grafting.

OBJECTIVE: Doppler ultrasound and digital plethysmography are used at our institution to determine the suitability of the radial artery for harvest prior to coronary artery bypass grafting (CABG). The purpose of this study is to determine the value of this preoperative evaluation. METHODS: A retrospective analysis of non-invasive radial artery testing was performed on 187 CABG patients. Criteria used to exclude radial arteries from harvest were anatomic abnormalities (size<2 mm, diffuse calcifications), and perfusion deficits during radial artery occlusion (>40% reduction in digital pressure, non-reversal of radial artery flow, or minimal increase in ulnar velocity). A questionnaire was used to determine the incidence of postoperative hand ischemia or rehabilitation. RESULTS: In 187 patients, 346 arms were evaluated. Ninety-four arms (27.1%) were excluded for harvesting. Anatomical abnormalities included size<2 mm (1.5%), diffuse calcifications (8.7%), congenital anomalies (2.3%), and radial artery occlusion (0.3%). Circulatory abnormalities included non-reversal of flow (7.2%), abnormal digital pressures (5.5%), and inappropriate increase in ulnar velocity (1.7%). A total of 116 radial arteries were harvested. There were no episodes of hand ischemia. No patient required hand rehabilitation. CONCLUSIONS Doppler ultrasound and digital plethysmography identifies both perfusion (14.5%) and anatomical (12.7%) abnormalities that may make the radial artery less suitable as a bypass conduit.

Collateral Circulation↗
PubMed1996

Value of body plethysmography in preoperative assessment of thoracotomy candidates.

The usefulness of body plethysmography in the assessment of thoracotomy candidates is not well documented. Reported thresholds for operability are generally expressed in absolute values, which do not take into account a patient's size, age or gender. Spirometric and plethysmographic data of 103 patients undergoing thoracotomy were examined for their ability to predict death due to cardiopulmonary insufficiency, pneumonia, and atelectasis during the first 30 postoperative days. Neither plethysmographic nor spirometric parameters could predict atelectasis. Patients who underwent lobectomy were susceptible to the development of atelectasis. A weak correlation between elevated functional residual capacity (FRC) and occurrence of postoperative pneumonia was found. Lung function testing was not able to separate survivors from non-survivors. Patients with pneumonia were at high risk of death in their postoperative course. Because of the non-linear relationship, a correlation coefficient between spirometric and plethysmographic variables was not calculated. The prevalence of cardiac risk factors was high, so the decision for invasive hemodynamic studies should rather be based upon a patient's history than restricted to patients with impaired lung function. Because of methodological differences, and probably insuitable reference values, body plethysmography cannot substitute for spirometry. For FRC and FRC to total lung capacity (FRC/ TLC) ratio, further investigations must be undertaken to establish a correct reference value.

Adult↗
PubMed2003

Open-flow plethysmography with pressure-decay compensation.

Whole-body plethysmography is widely used to measure ventilation in awake, unrestrained animals. However, the explicit solution for volumetric analysis of the plethysmograph signal depends upon a closed system, which limits experimental design. Although often used, open-flow plethysmography is complicated by the time-decay of pressure signals generated in the open chamber (e.g. equivalent volume displacements will yield different pressure pulse magnitudes depending upon the rate of application, dP/dt). This problem may be alleviated by first characterizing the time rate of pressure-decay, dP(k)/dt, as a function of pressure magnitude, P, in the plethysmograph, dP(k(P))/dt. Then for each point P(t) in the original signal, subtract the corresponding dP(k(P))(t)/dt from each dP(t)/dt of the original signal to determine the decay-compensated derivative for that point, dP*(t)/dt, and then numerically integrate dP*(t)/dt to generate a pressure-decay compensated signal. The result is a 'virtual closed plethysmograph' trace that enables confident quantitative determination of ventilatory events and volumes with the full advantage of an open-flow plethysmograph.

Animals↗