A plethysmographic technique for direct measurement of airway resistance in hamsters

1989 ◽  
Vol 66 (4) ◽  
pp. 1990-1994 ◽  
Author(s):  
S. Sato ◽  
S. Kato ◽  
E. Terada ◽  
K. Takahashi ◽  
S. Yasui
Keyword(s):  
Airway Resistance ◽  
Flow Sensor ◽  
Small Animals ◽  
Hot Wire ◽  
Pulmonary Resistance ◽  
Coefficients Of Variation ◽  
A New Technique ◽  
Male Golden Hamsters ◽  
Microflow Sensor ◽  
Gas Volume

We have developed a new technique to directly measure airway resistance (Raw) in small animals with a pressure-type body plethysmograph equipped with a hot-wire microflow sensor. Seventeen male golden hamsters weighing 70–84 g were studied. Change in alveolar pressure (delta PA) was calculated from total gas volume and the respired volume difference through the flow sensor between the midpoints of the tidal excursion curve, reflecting the thorax movement. The ratio of delta PA to the flow difference between those two midpoints gave Raw. Raw was compared with pulmonary resistance, and inspiratory and expiratory resistances were also compared. Raw was 0.44 +/- 0.06 (SE) cmH2O.ml-1.s. Mean of the coefficients of variation of Raw was 19.6 +/- 3.2% (SE). Raw was well correlated with pulmonary resistance (r = 0.93). We demonstrated that Raw could be directly measured in small animals with a hot-wire flow sensor and a plethysmographic technique, and the values were well correlated with previously reported pulmonary resistance.

Unrestrained video-assisted plethysmography: a noninvasive method for assessment of lung mechanical function in small animals

2008 ◽  
Vol 104 (1) ◽  
pp. 253-261 ◽  
Author(s):  
Jason H. T. Bates ◽  
John Thompson-Figueroa ◽  
Lennart K. A. Lundblad ◽  
Charles G. Irvin
Keyword(s):  
Airway Resistance ◽  
Breathing Pattern ◽  
Small Animals ◽  
Mechanical Function ◽  
Direct Link ◽  
Breathing Frequency ◽  
Noninvasive Method ◽  
Noninvasive Methods ◽  
Mean Values ◽  
Video Assisted

The assessment of lung mechanical function in small animals, particularly mice, is essential for investigations into the pathophysiology of pulmonary disease. The most accurate and specific methods for making this assessment are highly invasive and so provide data of questionable relevance to normality. By contrast, present noninvasive methods based on unrestrained plethysmography have no direct link to the mechanical properties of the lung. There is thus a need for a completely noninvasive method for determining lung mechanical function in small animals. In the present study, we demonstrate an extension of unrestrained plethysmography in which changes in lung volume are estimated via orthogonal video imaging of the thorax. These estimates are combined with the pressure swings recorded as mice breathe inside a heated and humidified chamber to yield an estimate of specific airway resistance (sRaw). We used this new technique, which we term “unrestrained video-assisted plethysmography” (UVAP), to measure sRaw in 11 BALB/c mice exposed to aerosols of saline, methacholine, and albuterol and obtained mean values of 0.71, 1.23 and 1.10 cmH2O·s, respectively. Mean breathing frequency was 4.3, 3.4, and 3.6 breaths/s, respectively, while the corresponding mean tidal volumes were 0.36, 0.44 and 0.37 ml, respectively. We conclude that UVAP, a noninvasive method, is able to provide usefully accurate estimates of sRaw and breathing pattern parameters in mice.

GaN-on-Si Thermoresistive Flow Sensor with Gold Hot-wire

2019 ◽  
Author(s):  
G. Rhys Jones ◽  
Julian W. Gardner ◽  
Timothy Vincent ◽  
Andrea De Luca ◽  
Giorgia Longobardi ◽  
...  
Keyword(s):  
Flow Sensor ◽  
Hot Wire ◽  
Gan On Si

scholarly journals The effect of gas exchange on multiple-breath nitrogen washout measures of ventilation inhomogeneity in the mouse

2014 ◽  
Vol 117 (9) ◽  
pp. 1049-1054 ◽  
Author(s):  
Mahesh Dharmakumara ◽  
G. Kim Prisk ◽  
Simon G. Royce ◽  
Merryn Tawhai ◽  
Bruce R. Thompson
Keyword(s):  
Gas Exchange ◽  
Continuous Process ◽  
Small Animal ◽  
Mouse Lung ◽  
Small Animals ◽  
Nitrogen Washout ◽  
Ventilation Inhomogeneity ◽  
Lung Clearance Index ◽  
Per Se ◽  
Gas Volume

Inert-gas washout measurements using oxygen, in the lungs of small animals, are complicated by the continuous process of oxygen consumption (V̇o2). The multiple-breath nitrogen washout (MBNW) technique uses the alveolar slope to determine measures of ventilation inhomogeneity in the acinar ( Sacin) and conducting ( Scond) airway regions, as well as overall inhomogeneity, as determined by the lung clearance index (LCI). We hypothesized that measured ventilation inhomogeneity in the mouse lung while it is alive is in fact an artifact due to the high V̇o2 in proportion to alveolar gas volume (Va), and not ventilation inhomogeneity per se. In seven male C57BL/6 mice, MBNW was performed alive and postmortem to derive measures with and without the effect of gas exchange, respectively. These results were compared with those obtained from an asymmetric multibranch point mathematical model of the mouse lung. There was no statistical difference in Sacin and LCI between alive and postmortem results ( Sacin alive = 0.311 ± 0.043 ml−1 and Sacin postmortem = 0.338 ± 0.032 ml−1, LCI alive = 7.0 ± 0.1 and LCI postmortem = 7.0 ± 0.1). However, there was a significant decrease in Scond from 0.086 ± 0.005 ml−1 alive to 0.006 ± 0.002 ml−1 postmortem ( P < 0 .01). Model simulations replicated these results. Furthermore, in the model, as V̇o2 increased, so did the alveolar slope. These findings suggests that the MBNW measurement of Scond in the mouse lung is confounded by the effect of gas exchange, a result of the high V̇o2-to-Va ratio in this small animal, and not due to inhomogeneity within the airways.

Development of Microfluidic Flow Sensor in a Polymeric Microchip

Volume 4 ◽  
2004 ◽  
Author(s):  
Juan David Salgado ◽  
Keisuke Horiuchi ◽  
Prashanta Dutta
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electronic Circuit ◽  
Glass Plate ◽  
Flow Sensor ◽  
Pdms Layer ◽  
Appreciable Change ◽  
Microfluidic Flow ◽  
Channel Thickness ◽  
Microflow Sensor

A microfluidic flow sensor has been developed to precisely measure the flow rate in a micro/nanofluidic channel for lab-on-a-chip applications. Mixed electroosmotic and pressure driven microflows are investigated using this sensor. Our microflow sensor consists of two components: fluidic circuit and electronic circuit. The fluidic circuit is embedded into the microfluidic chip, which is formed during the microfabrication sequences. On the other hand, the electronic circuit is a microelectronic chip that works as a logical switch. We have tested the microflow sensor in a hybrid poly di-methyl-siloxane (PDMS)-glass microchip using de-ionized (DI) water. Softlithography techniques are used to form the basic microflow structure on a PDMS layer, and all sensing electrodes are deposited on a glass plate using sputtering technique. In this investigation, the microchannel thickness is varied between 3.5 and 10 microns, and the externally applied electric field is ranged between 100V/mm and 200V/mm. The thickness of the gold electrodes is kept below 100nm, and hence the flow disturbance due to the electrodes is very minimal. Fairly repeatable flow results are obtained for all the channel dimensions and electric fields. Moreover, for a particular electric field strength, there is an appreciable change in the flow velocity with the change of the channel thickness.

Quiet-breathing vs. panting methods for determination of specific airway conductance

1984 ◽  
Vol 57 (6) ◽  
pp. 1917-1922 ◽  
Author(s):  
W. S. Krell ◽  
K. P. Agrawal ◽  
R. E. Hyatt
Keyword(s):  
Interobserver Variability ◽  
Direct Method ◽  
Normal Subjects ◽  
Intrasubject Variability ◽  
Quiet Breathing ◽  
Thoracic Gas Volume ◽  
Coefficients Of Variation ◽  
Gas Volume ◽  
Airway Conductance

Specific airway conductance (sGaw) was measured during quiet breathing and during panting in 21 normal subjects and 10 patients with obstructive lung disease. The direct method used does not require measuring thoracic gas volume (TGV). Coefficients of variation were 5.5% for panting and 5.1% for quiet breathing. Interobserver variability was 4.7% in the quiet-breathing method and 6.3% in the panting method. The two methods gave equivalent results for sGaw. A slightly greater sGaw was found by the panting method in normal subjects with the highest sGaw values, probably due to widening of the oropharynx-glottis during panting. In six normal subjects studied for intrasubject variability over time, no significant diurnal or day-to-day variability was seen by either method. We conclude that the quiet-breathing method is a simple valid means of determining sGaw and utilizes a physiological respiratory maneuver. Obviation of the need to measure TGV is advantageous. Results are equivalent to those of the panting method and variability is similar.

Hot-wire and hot-film anemometry and conditional measurements: A report on Euromech 132

1981 ◽  
Vol 110 ◽  
pp. 115-128 ◽  
Author(s):  
G. Comte-Bellot ◽  
G. Charnay ◽  
J. Sabot
Keyword(s):  
Fluid Flow ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Complex Flows ◽  
Pattern Recognition Analysis ◽  
Hot Wires ◽  
A New Technique ◽  
Hot Film ◽  
Sampling Pattern ◽  
Hot Film Anemometry

The European Mechanics Colloquium, Euromech 132, was held at the Ecole Centrale de Lyon from 2 to 4 July 1980. Specific areas of hot-wire or hot-film anemometry were presented and discussed, more especially the effect of the finite time constant of the wire supports, the use of yawed hot wires in supersonic flows, the possible improvement of vorticity meters, and multi-point measurements of wall-shear-stress fluctuations. Other subjects described during the meeting included a new technique for concentration measurements in flames, developments and new uses of digitization and conditional sampling, pattern recognition analysis of fluid flow from multi-point, multi-time velocity measurements, and new turbulence measurements in complex flows and in fluid-flow machinery.An exhibition of hot-wire and hot-film anemometers and associated equipment was held during the colloquium.

Airway anesthesia effects on hypercapnic breathing pattern in humans

1983 ◽  
Vol 55 (2) ◽  
pp. 368-376 ◽  
Author(s):  
T. Y. Sullivan ◽  
P. L. Yu
Keyword(s):  
Airway Resistance ◽  
Vital Capacity ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Inspiratory Time ◽  
Abrupt Increase ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Gas Volume

Minute ventilation (VE) and breathing pattern during an abrupt increase in fractional CO2 were compared in 10 normal subjects before and after airway anesthesia. Subjects breathed 7% CO2-93% O2 for 5 min before and after inhaling aerosolized lidocaine. As a result of airway anesthesia, VE and tidal volume (VT) were greater during hypercapnia, but there was no effect on inspiratory time (TI). Therefore, airway anesthesia produced an increase in mean inspiratory flow (VT/TI) during hypercapnia. The increase in VT/TI was compatible with an increase in neuromuscular output. There was no effect of airway anesthesia on the inspiratory timing ratio or the shape and position of the curve relating VT and TI. We also compared airway resistance (Raw), thoracic gas volume, forced vital capacity, forced expired volume at 1s, and maximum midexpiratory flow rate before and after airway anesthesia. A small (0.18 cmH2O X l-1 X s) decrease in Raw occurred after airway anesthesia that did not correlate with the effect of airway anesthesia on VT/TI. We conclude that airway receptors accessible to airway anesthesia play a role in hypercapnic VE.

A simplified method for stabilization of flail chest injuries in small animals

1995 ◽  
Vol 31 (2) ◽  
pp. 137-141 ◽  
Author(s):  
JF McAnulty
Keyword(s):  
Adverse Effects ◽  
Flail Chest ◽  
New Technique ◽  
Thoracic Wall ◽  
Small Animals ◽  
Device Application ◽  
Chest Injuries ◽  
Rib Fixation ◽  
Simplified Method ◽  
A New Technique

Two dogs and one cat with flail chest injuries were treated by a new technique of external thoracic wall stabilization using a single circumcostal suture for each affected rib and a splint device. Application of the splint device was quick and required minimal manipulation of the patient. Stabilization of the flail chest resulted in improved respiration in each animal. The splint device was left in place in two of the animals as the sole means of rib fixation. No evidence of infection or other adverse effects were noted with this technique.

Maturational changes in responses of tissue and airway resistance to histamine

1996 ◽  
Vol 81 (4) ◽  
pp. 1785-1791 ◽  
Author(s):  
Ismail A. Dreshaj ◽  
Musa A. Haxhiu ◽  
Charles F. Potter ◽  
Faton H. Agani ◽  
Richard J. Martin
Keyword(s):  
Airway Resistance ◽  
Lung Parenchyma ◽  
Developmental Differences ◽  
Postnatal Life ◽  
Receptor Blockade ◽  
Induced Responses ◽  
Pulmonary Resistance ◽  
Progressive Decline ◽  
Postnatal Maturation ◽  
Percent Increase

Dreshaj, Ismail A., Musa A. Haxhiu, Charles F. Potter, Faton H. Agani, and Richard J. Martin. Maturational changes in responses of tissue and airway resistance to histamine. J. Appl. Physiol. 81(4): 1785–1791, 1996.—We determined how postnatal maturation affects the relative contributions of airways and lung parenchyma to pulmonary resistance (Rl) and whether there are developmental differences in their respective responses to constrictive agents. We studied open-chest ventilated anesthetized piglets of three ages: 2–4 days, 2–3 wk, and 10 wk. Rl was partitioned into tissue (Rti) and airway (Raw) resistance by means of alveolar capsules under baseline conditions and after intravenous histamine. Postnatal maturation was associated with a progressive decline in Rl, Rti, and Raw and with an increase in the contribution of Rti to Rl from 38 ± 8% at 2–4 days to 72 ± 2% at both 2–3 and 10 wk. Histamine caused Rl to increase at all ages. When partitioned into Rti and Raw, the percent increase in Rti significantly exceeded that of Raw at both 2–4 days and 2–3 wk. In contrast, the percent increase in Raw significantly exceeded that of Rti at 10 wk. Administration of atropine before histamine in piglets aged 10 wk reduced the response of Rti and Raw to histamine. Histamine-induced responses of Rl were blocked by prior H1-receptor blockade with pyrilamine (2 mg/kg). These results indicate that 1) the contribution of Rti and Raw to Rl changes during maturation and that 2) contractile responses to exogenous histamine are manifest predominantly in most distal airways and lung parenchyma during early postnatal life; with advancing maturation there is greater contribution of airways to the increase in Rl induced by histamine.

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