Measurement of alveolar gas volume by ambient pressure changes in isolated lungs

1988 ◽  
Vol 65 (3) ◽  
pp. 1281-1285
Author(s):  
R. R. Martin ◽  
R. Peslin ◽  
C. Duvivier ◽  
C. Gallina
Keyword(s):  
Water Vapor ◽  
Ambient Pressure ◽  
Water Vapor Pressure ◽  
Volumetric Method ◽  
The Body ◽  
Highly Correlated ◽  
Isolated Lungs ◽  
Pressure Changes ◽  
Gas Volume ◽  
The Relationship

Alveolar gas volume (AGV) may be measured in humans (Peslin et al., J. Appl. Physiol. 62: 359-363, 1987) by applying very slow sinusoidal variations of ambient pressure (delta Pam) around the body and studying the relationship between delta Pam and the resulting gas displacement at the mouth (delta Vaw): AGVapc = (PB.delta Vaw)/(delta Pam.cos phi), where AGVapc is AGV measured by ambient pressure changes, PB is barometric minus alveolar water vapor pressure, and phi is the phase angle between Pam and Vaw. The applicability of this method to excised lungs at various transpulmonary pressures was assessed in six rabbit lungs and three dog lobes by reference to AGV measurements by He dilution (AGVdil) and by a volumetric method (AGVvol). Except in one instance, AGVapc did not change significantly when the frequency of delta Pam was varied from 0.02 to 0.2 Hz. AGVapc was highly correlated (P less than 0.001) to both AGVdil and AGVvol. It did not differ significantly from AGVdil (81.4 +/- 50.6 vs. 80.2 +/- 44.2 ml) and was only marginally higher than AGVvol (64.6 +/- 26.9 vs. 62.4 +/- 24.4 ml, P less than 0.05). We conclude that the method usually provides accurate results in excised lung preparations. Its main advantages are that it does not require manipulating the lung or changing its volume and that the measurement takes less than 1 min.

Thoracic gas volume in rabbits by low-frequency ambient pressure changes

1988 ◽  
Vol 65 (3) ◽  
pp. 1444-1448
Author(s):  
B. D. Lyttle ◽  
C. Duvivier ◽  
G. M. Glass ◽  
M. E. Wohl ◽  
J. J. Fredberg
Keyword(s):  
Small Mammals ◽  
Ambient Pressure ◽  
Low Frequency ◽  
Single Frequency ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
Highly Correlated ◽  
Pressure Changes ◽  
Gas Volume ◽  
Boyle’S Law

R. Peslin et al. measured thoracic gas volume (TGV) in adults using a new method employing low-frequency ambient pressure changes (APC) (J. Appl. Physiol. 62: 359-363, 1987). We extended that methodology and then tested the hypothesis that this technique was applicable to small mammals. TGV [at functional residual capacity (FRC)] by APC and by conventional Boyle's law was compared in 12 rabbits. The rabbits were anesthetized, tracheostomized, intubated, and placed in a pressure plethysmograph. Although in the method of Peslin et al. box pressure was oscillated at a single frequency, in our extension box pressure was oscillated simultaneously at two frequencies (0.1 and 0.2 Hz). Flow at the airway opening consisted of rapid events due to spontaneous breathing, superposed on slower events due to the alveolar gas compression. The slower events were analyzed to yield alveolar gas compliance and, by Boyle's law, FRC. FRC by APC was highly correlated to FRC by conventional plethysmography (r = 0.85). Compared with the methodology of Peslin et al., our extension relaxes a key limitation and yields systematically higher estimates of FRC. We conclude that this method is applicable to small mammals, despite an inherently more compliant chest wall, and that the methodological extension improves the estimate of FRC.

Measurement of thoracic gas volume by low-frequency ambient pressure changes

1987 ◽  
Vol 62 (1) ◽  
pp. 359-363
Author(s):  
R. Peslin ◽  
C. Duvivier ◽  
B. Hannhart ◽  
C. Gallina
Keyword(s):  
Gas Flow ◽  
Ambient Pressure ◽  
Water Vapor Pressure ◽  
Low Frequency ◽  
Normal Subjects ◽  
Whole Body ◽  
Body Plethysmography ◽  
Thoracic Gas Volume ◽  
Pressure Changes ◽  
Gas Volume

When the whole body is exposed to sinusoidal variations of ambient pressure (delta Pam) at very low frequencies (f), the resulting compression and expansion of alveolar gas is almost entirely achieved by gas flow through the airways (Vaw). As a consequence thoracic gas volume (TGV) may be computed from the imaginary part (Im) of the delta Pam/Vaw relationship: TGV = PB/[2 pi f X Im(delta Pam/Vaw)], where PB is barometric minus alveolar water vapor pressure. The method was tested in 35 normal subjects and compared with body plethysmography. The subjects sat in a chamber connected to a large-stroke-volume reciprocating pump that brought about pressure swings of 40 cmH2O at 0.05 Hz. delta Pam and Vaw were digitally processed by fast Fourier transform to extract the low-frequency component from the much larger respiratory flow. Total lung capacities (TLC) obtained by ambient pressure changes and by plethylsmography were highly correlated (r = 0.959, p less than 0.001) and not significantly different (6.96 +/- 1.38 l vs. 6.99 +/- 1.38). TLC obtained by ambient pressure changes were not influenced by lowering the frequency to 0.03 Hz, adding an external resistance at the mouth, or increasing abdominal gas volume. We conclude that the method is practical and in agreement with body plethysmography in normal subjects.

scholarly journals Analysis of Stress and Strain to Determine the Pressure Changes in Tight-Fitting Garment

2020 ◽  
Vol 20 (1) ◽  
pp. 49-55
Author(s):  
Nareerut Jariyapunya ◽  
Blažena Musilová
Keyword(s):  
Mechanical Properties ◽  
Mathematical Models ◽  
Initial Phase ◽  
Circumferential Stress ◽  
The Body ◽  
Stress And Strain ◽  
Laplace’S Law ◽  
Pressure Changes ◽  
The Relationship ◽  
Laplace's Law

AbstractBased on the mechanical properties of stretch fabrics and Laplace’s law, the mathematical models have been developed enabling one to determine the values of the relationship between the fabric strain and the circumferential stress depending on pressure and diameter of the body. The results obtained refer to the values of the parameters assessed for the initial phase of their exploitation, which allow us to preliminarily predict the values of these parameters.

scholarly journals Adiposity signals predict vocal effort in Alston's singing mice

2018 ◽  
Vol 285 (1877) ◽  
pp. 20180090 ◽  
Author(s):  
Tracy T. Burkhard ◽  
Rebecca R. Westwick ◽  
Steven M. Phelps
Keyword(s):  
Body Condition ◽  
Strong Predictor ◽  
Strong Relationship ◽  
The Body ◽  
Adiposity Signals ◽  
Vocal Effort ◽  
Highly Correlated ◽  
Costly Traits ◽  
Somatic State ◽  
The Relationship

Advertisement displays often seem extravagant and expensive, and are thought to depend on the body condition of a signaller. Nevertheless, we know little about how signallers adjust effort based on condition, and few studies find a strong relationship between natural variation in condition and display. To examine the relationship between body condition and signal elaboration more fully, we characterized physiological condition and acoustic displays in a wild rodent with elaborate vocalizations, Alston's singing mouse, Scotinomys teguina . We found two major axes of variation in condition—one defined by short-term fluctuations in caloric nutrients, and a second by longer-term variation in adiposity. Among acoustic parameters, song effort was characterized by high rates of display and longer songs. Song effort was highly correlated with measures of adiposity. We found that leptin was a particularly strong predictor of display effort. Leptin is known to influence investment in other costly traits, such as immune function and reproduction. Plasma hormone levels convey somatic state to a variety of tissues, and may govern trait investment across vertebrates. Such measures offer new insights into how animals translate body condition into behavioural and life-history decisions.

scholarly journals Features of glossopharyngeal breathing in breath-hold divers

2006 ◽  
Vol 101 (3) ◽  
pp. 799-801 ◽  
Author(s):  
Leigh M. Seccombe ◽  
Peter G. Rogers ◽  
Nghi Mai ◽  
Chris K. Wong ◽  
Leonard Kritharides ◽  
...  
Keyword(s):  
Vital Capacity ◽  
Total Lung Capacity ◽  
Breath Hold ◽  
Lung Capacity ◽  
Diving Depth ◽  
Highly Correlated ◽  
Pressure Changes ◽  
Air Compression ◽  
The Relationship ◽  
Measured Volume

One technique employed by competitive breath-hold divers to increase diving depth is to hyperinflate the lungs with glossopharyngeal breathing (GPB). Our aim was to assess the relationship between measured volume and pressure changes due to GPB. Seven healthy male breath-hold divers, age 33 ( 8 ) [mean (SD)] years were recruited. Subjects performed baseline body plethysmography (TLCPRE). Plethysmography and mouth relaxation pressure were recorded immediately following a maximal GPB maneuver at total lung capacity (TLC) (TLCGPB) and within 5 min after the final GPB maneuver (TLCPOST). Mean TLC increased from TLCPRE to TLCGPB by 1.95 (0.66) liters and vital capacity (VC) by 1.92 (0.56) liters ( P < 0.0001), with no change in residual volume. There was an increase in TLCPOST compared with TLCPRE of 0.16 liters (0.14) ( P < 0.02). Mean mouth relaxation pressure at TLCGPB was 65 (19) cmH2O and was highly correlated with the percent increase in TLC ( R = 0.96). Breath-hold divers achieve substantial increases in measured lung volumes using GPB primarily from increasing VC. Approximately one-third of the additional air was accommodated by air compression.

Simulation of three-dimensional female body shapes with proportional representation for various weights and heights

SIMULATION ◽  
2020 ◽  
Vol 96 (11) ◽  
pp. 851-866
Author(s):  
Chanjira Sinthanayothin ◽  
Wisarut Bholsithi ◽  
Duangrat Gansawat ◽  
Nonlapas Wongwaen ◽  
Piyanut Xuto ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Three Dimensional ◽  
3D Models ◽  
The Body ◽  
Body Proportions ◽  
Body Proportion ◽  
3D Scanners ◽  
Highly Correlated ◽  
Body Shapes ◽  
The Relationship

Obesity is a significant factor in health information and increases the risk of health problems. Hence, an application that can help users to monitor their body mass index (BMI) timelines is needed. The simulation of a personalized 3D body shape may encourage women to control their BMI for a healthy body and pleasant appearance. Therefore, this paper aims to develop computerized 3D models of female shapes for various weights and heights, and consists of three important parts. First, the preparation of six avatars is described. Second, the body proportions of 6767 female datasets are analyzed to find the relationship of variables in various weights and heights. Last, 3D morphing of different female shapes is developed and analyzed experimentally for appropriate morphing parameters. Accuracy tests are carried out in three ways. First, body proportions calculated using the Z-Size Ladies application, called “Z-Size calculations,” are compared with the body proportions of data obtained from 3D scanners. Second, the Z-Size calculations are compared with tape measurements. Last, the Z-Size calculations are compared with measurements of Z-Size 3D morph models. The results of accuracy tests are shown as the relationship graphs between the BMI and body proportion measurements of chest, waist, hip, and inseam. Bland–Altman plots and Pearson correlation calculation show high correlation. In conclusion, the data obtained from the Z-Size calculations, 3D Scanner, tape measurements, and Z-Size morph models’ measurements are in good agreement and are highly correlated. The simulation of 3D female shapes for different weights and heights as proposed shows good performance and high accuracy.

Regional relationship of water vapor pressure of human body surface

1963 ◽  
Vol 18 (5) ◽  
pp. 1019-1024 ◽  
Author(s):  
Kokichi Ohara ◽  
Takeo Ono
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Absolute Humidity ◽  
Skin Surface ◽  
The Body ◽  
Insensible Perspiration ◽  
Regional Relationship ◽  
Relationship Of

A new simple method for measurement of water discharge from the skin, as well as for estimation of absolute and relative humidity of the skin surface, was reported. The accuracy of the method was high with errors in the order of 2.5%. Estimations were made, using this method, at 108 points over the body of a young healthy nude male subject under neutral thermal conditions. Regional relationship of the rate of insensible perspiration, as well as the absolute and relative humidity of the skin surface, were obtained from the experiments. There was no difference between the regional relationship of the insensible perspiration and that of the absolute humidity. In the regions where perspiration rate is high, the water vapor pressure of the skin surface is also high. Sole, face, palm, and neck are the highest regions. Back of hands and gluteal region are the second highest zone. In distal parts of extremities, there exists an increasing gradient toward the palm or the sole. In the median region of the chest and epigastrium the values are somewhat higher though the chest and abdomen as a whole belong to the lowest regions. Distribution of the relative humidity showed no great difference in general from that of the perspiration rate or absolute humidity. It was found that the regional relationship is not perfectly symmetrical in both sides of the body. Submitted on January 16, 1963

Variations in air viscosity due to changes in water vapor pressure for isothermal conditions at temperatures below 40 °C

1970 ◽  
Vol 48 (1) ◽  
pp. 50-53 ◽  
Author(s):  
P. D. Roy ◽  
W. T. Josenhans ◽  
C. H. Miller
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Work Of Breathing ◽  
Water Vapor Pressure ◽  
Respiratory Muscles ◽  
Work Load ◽  
Reynolds Numbers ◽  
Pressure Drops ◽  
Isothermal Test ◽  
The Relationship

The viscosities of moist and dry air were measured at four temperatures to determine variations due to changes in water vapor content under isothermal test conditions. Paired measurements (240) of volumetric rates of air flow and pressure drops along a tube were made. Corresponding coefficients of viscosity were calculated from the Hagen–Poiseuille equation, laminar flow being assured by limiting maximal Reynolds numbers. The relationship between viscosity (η) and water vapor pressure [Formula: see text] was found to be approximately linear. The increase in the work load of the respiratory muscles due to an increase in air humidity, and hence viscosity, from purely physical considerations, appears to be very small compared with the total work of breathing.

scholarly journals Predicting body weight from body measurements of pre-pubertal Ayrshire heifers

1996 ◽  
Vol 5 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Päivi Mäntysaari
Keyword(s):  
Body Weight ◽  
Regression Analysis ◽  
Actual Body ◽  
Body Length ◽  
The Body ◽  
Body Measurements ◽  
Actual Body Weight ◽  
Feeding Level ◽  
Highly Correlated ◽  
The Relationship

The relationship between heart girth, wither height, body length and body weight in 3- to 9.5-month-old pre-pubertal Finnish Ayrshire heifers gaining 600-650 g/d was analysed (experiment I). Regression analysis showed that heart girth was the trait most highly correlated to body weight (R2 = 0.969). Including body length or wither height as a second term in the regression, increased R2 values only slightly. When the relationship between heart girth and body weight was used to predict the body weight of heifers reared at two feeding levels (experiment II), the precision of prediction was affected by the plane of nutrition. Actual body weight for a given heart girth was slightly higher on the high than on the low feeding level. It is, nevertheless, concluded that the equations presented in the paper can be used to estimate accurately the body weight of pre-pubertal (95-140-cm heart girth) Ayrshire heifers gaining 550-700 g/d.

Comparison of plethysmographic methods for obtaining thoracic gas volume in anesthetized dogs

1985 ◽  
Vol 59 (2) ◽  
pp. 653-657 ◽  
Author(s):  
J. A. Armengol ◽  
R. L. Jones ◽  
E. G. King
Keyword(s):  
The Body ◽  
Lung Model ◽  
Respiratory Center ◽  
Dilution Method ◽  
External Compression ◽  
Thoracic Gas Volume ◽  
Isolated Lung ◽  
Anesthetized Dogs ◽  
Pressure Changes ◽  
Gas Volume

Thoracic gas volume (TGV) cannot be measured in the body plethysmograph by the standard spontaneous breathing technique (SB) when there is a significant respiratory center depression. In this case, either external compression of the chest wall (EC) or phrenic nerve stimulation (PhN) can be used to induce the pressure-volume changes necessary to calculate TGV. In the present study we compared TGV measured in eight pentobarbital-anesthetized dogs by SB, EC, PhN, and the standard He-dilution method. EC and simulated PhN were also used to measure the volume of a lung model, and EC was used to measure the volume of isolated lung lobes. A method for fast and accurate plethysmographic calibration is also described. In the intact dogs, SB, PhN, and He-dilution techniques gave similar results, but EC overestimated TGV. In the isolated lobes and lung model EC accurately measured volume. We speculate that EC induces substantial intersegmental and/or interlobal gas movement in intact lungs and that the pressure drop due to airway resistance causes proximal airway pressure to underestimate alveolar pressure changes, which induces overestimation in calculated TGV. We conclude that PhN is the method of choice to measure plethysmographic TGV when the respiratory center is depressed and that EC overestimates TGV in intact dogs.

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