A reevaluation of the validity of unrestrained plethysmography in mice

2002 ◽  
Vol 93 (4) ◽  
pp. 1198-1207 ◽  
Author(s):  
Lennart K. A. Lundblad ◽  
Charles G. Irvin ◽  
Andy Adler ◽  
Jason H. T. Bates
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Airway Resistance ◽  
Ambient Conditions ◽  
Closed Chamber ◽  
Time Integral ◽  
Gas Compression ◽  
Compression And Expansion ◽  
Residual Capacity ◽  
Gas Conditioning

Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [Pb( t), where t is time] and assumed to be an index of bronchoconstriction. We show that Pb( t) is determined largely by gas conditioning when normal mice breathe spontaneously inside a closed chamber in which the air is at ambient conditions. When the air in the chamber is heated and humidified to body conditions, the changes in Pb( t) are reduced by about two-thirds. The remaining changes are thus due to gas compression and expansion within the lung and are amplified when the animals breathe through increased resistances. We show that the time integral of Pb( t) over inspiration is accurately predicted by a term containing airway resistance, functional residual capacity, and tidal volume. We conclude that unrestrained plethysmography can be used to accurately characterize changes in airway resistance only if functional residual capacity and tidal volume are measured independently and the chamber gas is preconditioned to body temperature and humidity.

Dynamic mechanisms determine functional residual capacity in mice, Mus musculus

1979 ◽  
Vol 46 (5) ◽  
pp. 867-871 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
D. E. Leith
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Flow Volume ◽  
Linear Portion ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
The Difference ◽  
Pentobarbital Sodium Anesthesia

Awake mice (22.6--32.6 g) were anesthetized intravenously during head-out body plethysmography. One minute after pentobarbital sodium anesthesia, tidal volume had fallen from 0.28 +/- 0.04 to 0.14 +/- 0.02 ml and frequency from 181 +/- 20 to 142 +/- 8. Functional residual capacity (FRC) decreased by 0.10 +/- 0.02 ml. Expiratory flow-volume curves were linear, highly repeatable, and submaximal over substantial portions of expiration in awake and anesthetized mice; and expiration was interrupted at substantial flows that abruptly fell to and crossed zero as inspiration interrupted relaxed expiration. FRC is maintained at a higher level in awake mice due to a higher tidal volume and frequency coupled with expiratory braking (persistent inspiratory muscle activity or increased glottal resistance). In anesthetized mice, the absence of braking, coupled with reductions in tidal volume and frequency and a prolonged expiratory period, leads to FRCs that approach relaxation volume (Vr). An equation in derived to express the difference between FRC and Vr in terms of the portion of tidal volume expired without braking, the slope of the linear portion of the expiratory flow-volume curve expressed as V/V, the time fraction of one respiratory cycle spent in unbraked expiration, and respiratory frequency.

Estimation of pulmonary ventilation with nitrogen and helium, using the mass spectrometer

1959 ◽  
Vol 14 (4) ◽  
pp. 499-506 ◽  
Author(s):  
K. Tokuyasu ◽  
A. Coblentz ◽  
H. R. Bierman
Keyword(s):  
Tidal Volume ◽  
Mass Spectrometer ◽  
Functional Residual Capacity ◽  
Pulmonary Ventilation ◽  
Normal Subjects ◽  
Alveolar Ventilation ◽  
Pulmonary Lesions ◽  
Normal Subject ◽  
Residual Capacity ◽  
Uneven Ventilation

Estimation of pulmonary ventilation was attempted by measuring the elimination of nitrogen and helium with the mass spectrometer. Exhalatory concentrations of nitrogen and helium were continuously recorded in each of 12 normal subjects and 10 patients with pulmonary enphysema or space-occupying pulmonary lesions. Uniform values for both slow and rapid uneven ventilation were found in all normal subjects but always less than in emphysematous states. Ratios of effective tidal volume (Vt) and alveolar ventilation volume (f·Vt) to functional residual capacity P = Vt/Vr and Q = f·Vt/Vr were one half or less than those in the normal subject. Smaller values of uneven ventilation were found for helium than nitrogen. Data computed by the theory of 'periodic' ventilation gave greater values for uneven ventilation (Q) and more accurately represented the physiologic conditions than derived by ‘continuous’ ventilation. Submitted on August 7, 1958

Ventilatory compensation for changes in functional residual capacity during sleep

1987 ◽  
Vol 62 (3) ◽  
pp. 1299-1306 ◽  
Author(s):  
R. L. Begle ◽  
J. B. Skatrud ◽  
J. A. Dempsey
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Minute Ventilation ◽  
Muscle Length ◽  
Normal Subjects ◽  
Conscious State ◽  
Inspiratory Muscle ◽  
Compensatory Response ◽  
Inspiratory Muscles ◽  
Residual Capacity

The role of conscious factors in the ventilatory compensation for shortened inspiratory muscle length and the potency of this compensatory response were studied in five normal subjects during non-rapid-eye-movement sleep. To shorten inspiratory muscles, functional residual capacity (FRC) was increased and maintained for 2–3 min at a constant level (range of increase 160–1,880 ml) by creating negative pressure within a tank respirator in which the subjects slept. Minute ventilation was maintained in all subjects over the entire range of increased FRC (mean change +/- SE = -3 +/- 1%) through preservation of tidal volume (-2 +/- 2%) despite slightly decreased breathing frequency (-6 +/- 2%). The decrease in frequency (-13 +/- 2%) was due to a prolongation in expiratory time. Inspiratory time shortened (-10 +/- 1%). Mean inspiratory flow increased 15 +/- 3% coincident with an increase in the slope of the moving time average of the integrated surface diaphragmatic electromyogram (67 +/- 21%). End-tidal CO2 did not rise. In two subjects, control tidal volume was increased 35–50% with CO2 breathing. This augmented tidal volume was still preserved when FRC was increased. We concluded that the compensatory response to inspiratory muscle shortening did not require factors associated with the conscious state. In addition, the potency of this response was demonstrated by preservation of tidal volume despite extreme shortening of the inspiratory muscles and increase in control tidal volumes caused by CO2 breathing. Finally, the timing changes we observed may be due to reflexes following shortening of inspiratory muscle length, increase in abdominal muscle length, or cardiovascular changes.

Pulmonary compliance and nonelastic resistance during treadmill exercise

1965 ◽  
Vol 20 (6) ◽  
pp. 1194-1198 ◽  
Author(s):  
S. T. Chiang ◽  
Neal H. Steigbigel ◽  
Harold A. Lyons
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Treadmill Exercise ◽  
Normal Subjects ◽  
Lung Compliance ◽  
Respiratory Frequency ◽  
Respiratory Flow ◽  
Pulmonary Compliance ◽  
Exercise Effect ◽  
Residual Capacity

Trans-pulmonary pressure, respiratory flow, and tidal volume of seven normal subjects were measured at rest and during treadmill exercise on the level at a speed of 1.5 mph. Pulmonary compliance remained unchanged during exercise. Nonelastic resistance showed an insignificant increase (0.9—1.4 cm H2O per liter per sec). Examination of other parameters which may affect compliance were made. Functional residual capacity decreased 120—200 ml during exercise, tidal volume doubled, and respiratory frequency increased 43.5%, yet none of these factors affected the lung compliance. The phenomenon of “second wind” was experienced by four of the subjects, and nothing was observed to explain its occurrence during exercise. exercise second wind; change in functional residual capacity during exercise; effect of functional residual capacity on compliance; effect of tidal volume on compliance during exercise; effect of respiratory frequency on compliance Submitted on January 15, 1965

scholarly journals Tidal volume, cardiac output and functional residual capacity determine end-tidal CO2transient during standing up in humans

2004 ◽  
Vol 554 (2) ◽  
pp. 579-590 ◽  
Author(s):  
Janneke Gisolf ◽  
Ronald Wilders ◽  
Rogier V. Immink ◽  
Johannes J. Van Lieshout ◽  
John M. Karemaker
Keyword(s):  
Cardiac Output ◽  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Standing Up ◽  
Residual Capacity ◽  
End Tidal

Calibration of respiratory inductive plethysmograph during natural breathing

1989 ◽  
Vol 66 (1) ◽  
pp. 410-420 ◽  
Author(s):  
M. A. Sackner ◽  
H. Watson ◽  
A. S. Belsito ◽  
D. Feinerman ◽  
M. Suarez ◽  
...  
Keyword(s):  
Linear Regression ◽  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Rib Cage ◽  
Proportionality Constant ◽  
Supine Posture ◽  
Residual Capacity ◽  
Standard Deviations ◽  
Natural Breathing

We describe a single-posture method for deriving the proportionality constant (K) between rib cage (RC) and abdominal (AB) amplifiers of the respiratory inductive plethysmograph (RIP). Qualitative diagnostic calibration (QDC) is based on equations of the isovolume maneuver calibration (ISOCAL) and is carried out during a 5-min period of natural breathing without using mouthpiece or mask. In this situation, K approximates the ratio of standard deviations (SD) of the uncalibrated changes of AB-to-RC volume deflections. Validity of calibration was evaluated by 1) analyzing RIP waveforms during an isovolume maneuver and 2) comparing changes of tidal volume (VT) amplitude and functional residual capacity (FRC) level measured by spirometry (SP) with RIP values. Comparisons of VT(RIP) to VT(SP) were also obtained in a variety of postures during natural (uninstructed) preferential RC and AB breathing and with voluntary changes of VT amplitude and FRC level. VT(RIP)-to-VT(SP) comparisons were equal to or closer than published reports for single posture, ISOCAL, multiple- and linear-regression procedures. QDC of RIP in supine posture with comparisons to SP in that posture and others showed better accuracy in horizontal than upright postures.

scholarly journals Effects of chest wall vibration on tidal volume and functional residual capacity in healthy volunteers.

1987 ◽  
Vol 7 (3) ◽  
pp. 341-346
Author(s):  
Jun KATAGIRI ◽  
Akito OHMURA ◽  
Nobuaki MORIYASU ◽  
Midori OZAWA ◽  
Michiko YAMADA ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Healthy Volunteers ◽  
Chest Wall ◽  
Functional Residual Capacity ◽  
Residual Capacity
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