Respiratory resistance from 1 to 46 ATA measured with the interrupter technique

Clarke, JR; Jaeger, Marc; Zumrick, JL; O'Bryan, Robert K; Spaur, WH

doi:10.1152/jappl.1982.52.3.549

Cited by 17 publications

(7 citation statements)

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“…Airway resistance at sea level using the P .1 technique are not different from those measured using the esophageal balloon method (179,252). In the past the P .1 was used to estimate P A and to calculate airway resistance in subjects submersed at depths of 45 ATA (63).…”

Section: Work and Energy Cost Of Breathing Underwatermentioning

confidence: 98%

Human Physiology in an Aquatic Environment

Pendergast

Moon

Krasney

et al. 2015

Comprehensive Physiology

136

137

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Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system.

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Section: Work and Energy Cost Of Breathing Underwatermentioning

confidence: 98%

Human Physiology in an Aquatic Environment

Pendergast

Moon

Krasney

et al. 2015

Comprehensive Physiology

136

137

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show abstract

“…Mechanisms that may contribute include the following. 1) Hypoventilation secondary to increased work of breathing may be due to the effects of increased gas density (10). Expiratory flow is limited by an increase in airway resistance, and inspiratory elastic work is increased because of breathing at a higher lung volume (51).…”

mentioning

confidence: 99%

Effects of age and exercise on physiological dead space during simulated dives at 2.8 ATA

Mummery

Stolp

Dear

et al. 2003

Journal of Applied Physiology

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Physiological dead space (Vds), end-tidal CO(2) (Pet(CO(2))), and arterial CO(2) (Pa(CO(2))) were measured at 1 and 2.8 ATA in a dry hyperbaric chamber in 10 older (58-74 yr) and 10 younger (19-39 yr) air-breathing subjects during rest and two levels of upright exercise on a cycle ergometer. At pressure, Vd (liters btps) increased from 0.34 +/- 0.09 (mean +/- SD of all subjects for normally distributed data, median +/- interquartile range otherwise) to 0.40 +/- 0.09 (P = 0.0060) at rest, 0.35 +/- 0.13 to 0.45 +/- 0.11 (P = 0.0003) during light exercise, and 0.38 +/- 0.17 to 0.45 +/- 0.13 (P = 0.0497) during heavier exercise. During these conditions, Pa(CO(2)) (Torr) increased from 33.8 +/- 4.2 to 35.7 +/- 4.4 (P = 0.0059), 35.3 +/- 3.2 to 39.4 +/- 3.1 (P < 0.0001), and 29.6 +/- 5.6 to 37.4 +/- 6.5 (P < 0.0001), respectively. During exercise, Pet(CO(2)) overestimated Pa(CO(2)), although the absolute difference was less at pressure. Capnography poorly estimated Pa(CO(2)) during exercise at 1 and 2.8 ATA because of wide variability. Older subjects had higher Vd at 1 ATA but similar changes in Vd, Pa(CO(2)), and Pet(CO(2)) at pressure. These results are consistent with an effect of increased gas density.

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“…It is noninvasive, requires minimum patient co-operation and its brevity and the absence of an oscillating column of air suggests that it may be generally better tolerated by young patients than the FOT. Responses such as glottic narrowing are unlikely to occur, because measurements are virtually imperceptible and are made during quiet breathing Recently, the physiological basis and clinical utility of the interrupter technique has been re-evaluated, with some promising results [14][15][16], and theoretical analysis by BATES et al [17] has validated the technique. Although upper airway compliance may lead to an underestimation of airway resistance [18], this can be minimized by supporting the cheeks and floor of the mouth.…”

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confidence: 99%

A portable device based on the interrupter technique to measure bronchodilator response in schoolchildren

Bridge

Lee²,

Silverman³

1996

European Respiratory Journal

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A new device for measuring airway resistance following brief airflow interruption (Microlab 4000; Micromedical Ltd, UK) was evaluated in 25 asthmatic school children in comparison with well-established methods.Airway resistance was measured during brief airflow interruption (Rint), before and after administration of salbutamol 200 µg by metered-dose inhaler, and in the spirometric parameters, forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), and total respiratory system resistance at 6 Hz (Rrs,6) measured by the forced oscillation technique (FOT). The sensitivity index (SI) (mean change/baseline standard deviation) was calculated for each subject.At baseline, interrupter conductance, the reciprocal of Rint, correlated well with FEV1 (r=0.837; p<0.001) and PEF (r=0.773; p <0.001), and Rint correlated highly with Rrs,6 (r=0.942; p<0.001). The median intrasubject coefficient of variation of the interrupter method was higher than the FOT or either spirometric parameter: Rint 11%, Rrs,6 9%, FEV1 5% and PEF 5%. However, the sensitivity to detect change after bronchodilator, expressed as the median SI, did not differ significantly between measurements: Rint 3.5, Rrs,6 3.6, FEV1 2.4 and PEF 3.0. A significant response (SI >2) was shown by the interrupter in 22 of the subjects compared with 16 by FEV1.The interrupter technique is useful for assessing changes in airway calibre in asthmatic school children, with a sensitivity at least as good as standard methods. Such a device could be of particular value in those too young to perform spirometry.

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Respiratory resistance from 1 to 46 ATA measured with the interrupter technique

Cited by 17 publications

References 0 publications

Human Physiology in an Aquatic Environment

Human Physiology in an Aquatic Environment

Effects of age and exercise on physiological dead space during simulated dives at 2.8 ATA

A portable device based on the interrupter technique to measure bronchodilator response in schoolchildren

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