The Use of Hydrogen as an Inert Gas During Diving: Pulmonary Function During Hydrogen-Oxygen Breathing at Pressures Equivalent to 200 Feet of Sea Water

1974 ◽  
Author(s):  
Jr Dougherty ◽  
James H.
Keyword(s):  
Pulmonary Function ◽  
Sea Water ◽  
Inert Gas ◽  
Oxygen Breathing

Pulmonary function in men after oxygen breathing at 3.0 ATA for 3.5 h

1991 ◽  
Vol 71 (3) ◽  
pp. 878-885 ◽  
Author(s):  
J. M. Clark ◽  
R. M. Jackson ◽  
C. J. Lambertsen ◽  
R. Gelfand ◽  
W. D. Hiller ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Large Change ◽  
Forced Expiratory Volume ◽  
Diffusing Capacity ◽  
Mild Degree ◽  
Oxygen Breathing ◽  
Multiple Organs ◽  
Expiratory Flow

As a pulmonary component of Predictive Studies V, designed to determine O2 tolerance of multiple organs and systems in humans at 3.0–1.5 ATA, pulmonary function was evaluated at 1.0 ATA in 13 healthy men before and after O2 exposure at 3.0 ATA for 3.5 h. Measurements included flow-volume loops, spirometry, and airway resistance (Raw) (n = 12); CO diffusing capacity (n = 11); closing volumes (n = 6); and air vs. HeO2 forced vital capacity maneuvers (n = 5). Chest discomfort, cough, and dyspnea were experienced during exposure in mild degree by most subjects. Mean forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25–75% of vital capacity (FEF25–75) were significantly reduced postexposure by 5.9 and 11.8%, respectively, whereas forced vital capacity was not significantly changed. The average difference in maximum midexpiratory flow rates at 50% vital capacity on air and HeO2 was significantly reduced postexposure by 18%. Raw and CO diffusing capacity were not changed postexposure. The relatively large change in FEF25–75 compared with FEV1, the reduction in density dependence of flow, and the normal Raw postexposure are all consistent with flow limitation in peripheral airways as a major cause of the observed reduction in expiratory flow. Postexposure pulmonary function changes in one subject who convulsed at 3.0 h of exposure are compared with corresponding average changes in 12 subjects who did not convulse.

DROWNING AND THE TREATMENT OF NON-FATAL SUBMERSION

PEDIATRICS ◽  
1966 ◽  
Vol 37 (4) ◽  
pp. 684-698
Author(s):  
Jerome Imburg ◽  
Thomas C. Hartney
Keyword(s):  
Ventricular Fibrillation ◽  
Pulmonary Function ◽  
Fresh Water ◽  
Animal Studies ◽  
Sea Water ◽  
The Body ◽  
Positive Pressure ◽  
Cardiac Massage ◽  
Central Nervous System Damage ◽  
Intermittent Positive Pressure Breathing

Animal studies have shown that fluid enters the body via the lungs in sea-water and fresh-water drowning. In fresh-water drowning in dogs, there is marked and rapid hemodilution with death due to ventricular fibrillation in about 4 minutes. In sea-water drowning in dogs, there is hemoconcentration; the blood water is lost into the sea water in the lungs with bradycardia and death due to asystole in 6 to 8 minutes. Studies of human drowning victims show similar, but less striking, changes in hemodynamics. In human non-fatal submersion the problems are usually those produced by impaired pulmonary function and central nervous system damage due to hypoxia. Hemodilution and ventricular fibrillation have not been documented in human nonfatal submersion. Therapeutic measures may be divided into those of an immediate urgent nature to be employed at the accident scene: expired air resuscitation, which should be started on reaching the unconscious victim in the water, and external cardiac massage, when indicated. Later measures to be instituted in the hospital include: cardiac resuscitation, intermittent positive-pressure breathing, hypothermia, tracheostomy and tracheal tiolet, oxygen therapy, antibiotics, steroids, and intravenous fluids to correct defects in blood elements (hemoglobin, electrolytes, pH). Later, pulmonary function should be studied for impairment due to alveolar damage and fibrosis. Permanent neurologic sequellae may develop.

Oxygen-induced alteration of ventilation-perfusion relationships in rats

1979 ◽  
Vol 47 (5) ◽  
pp. 1112-1117 ◽  
Author(s):  
W. E. Truog ◽  
M. P. Hlastala ◽  
T. A. Standaert ◽  
H. P. McKenna ◽  
W. A. Hodson
Keyword(s):  
Gas Exchange ◽  
Pulmonary Gas Exchange ◽  
Inert Gas ◽  
Base Line ◽  
Small Animals ◽  
Difference Curve ◽  
Oxygen Breathing ◽  
Anesthetized Rats ◽  
Effect Of Oxygen ◽  
Breathing Room

The effect of oxygen breathing on shunt and ventilation-perfusion ratios (VA/Q) in anesthetized rats was studied using a modification of the multiple inert gas elimination technique. Base-line analyses showed hypoxemia in some animals breathing room air (arterial O2 tensions 48-70 Torr) associated with intrapulmonary shunts ranging from 0 to 22%, and variable low VA/Q lung regions as determined by calculation of the inert gas arterial-alveolar difference curve. Of nine rats that breathed 100% oxygen for 30 min, three showed increases in shunt (0% leads to 19%, 1.5% leads to 16%, 11% leads to 40%). These three animals had larger preexisting low VA/Q regions than the six that developed no shunt (0.48 +/- 0.15 vs. 0.17 +/- 0.03 (mean +/- SD); P less than 0.05). These data are compatible with the theory of absorption atelectasis. This study documents the usefulness of the inert gas elimination technique for studying pulmonary gas exchange problems in small animals.

Instability of lung units with low Va/Q ratios during O2 breathing

1975 ◽  
Vol 38 (5) ◽  
pp. 886-895 ◽  
Author(s):  
David R. Dantzker ◽  
Peter D. Wagner ◽  
John B. West
Keyword(s):  
Venous Blood ◽  
Capillary Blood ◽  
Inert Gas ◽  
Mixed Venous Blood ◽  
Gas Uptake ◽  
Oxygen Breathing ◽  
Infusion Method ◽  
Net Flux ◽  
Ventilation Perfusion Ratio ◽  
Mixed Venous

Using a multiple inert gas infusion method, we have observed the development of shunts during oxygen breathing in lungs which contained areas of low ventilation-perfusion ratios while breathing air. This paper gives a theoretical analysis of the factors involved. When the inspired ventilation-perfusion ratio (VaI/Q) of a lung unit is gradually reduced, a point is reached where the expired ventilation falls to zero. Such a unit will no longer eliminate gas but may continue gas uptake unless it becomes atelectatic. This critical VaI/Q is determined by the net flux of O2, CO2, and N2 from alveolar gas to capillary blood, and its value increases from about 0.001 to 0.1 as the inspired gas is changed from air to 100% O2. The critical VaI/Q at any inspired O2 concentration is raised if the O2 or N2content of mixed venous blood are reduced or if N2 is replaced by a more soluble gas. In distributions of ventilation-perfusion ratios, the amount of shunt which develops during oxygen breathing depends on the degree of dispersion of the VaI ratios. The release of hypoxic vasoconstruction following O2 administration, in general, reduces the amount of shunt.

An "electronic lung" in the stud Y of pulmonary function

SIMULATION ◽  
1966 ◽  
Vol 7 (6) ◽  
pp. 311-316 ◽  
Author(s):  
Benjamin M. Lewis
Keyword(s):  
Mathematical Model ◽  
Carbon Monoxide ◽  
Pulmonary Function ◽  
Computer Model ◽  
Dead Space ◽  
Analog Computer ◽  
Inert Gas ◽  
Diffusing Capacity

A mathematical model of the lung, consisting of two regions and a common dead space, is described. An analog computer is used to solve the equations of this model. Two examples are given. In the first, curves of the mixing of an inert gas and the absorption of carbon monoxide obtained in emphysema patients are analyzed. Such curves were the result, in terms of our model, of a small, well-ventilated region with a low diffusing capacity and a large poorly ventilated region having most of the diffusing capacity of the lung. The computer model is modified and used to predict the effects on inert gas washout of ventilating the lung in various sequences. The slowest washout is obtained when the poorly ventilated region filled first and emptied last, the most rapid when this region filled last and emptied last. Sequential ventilation alone can produce relatively minor delays in inert gas washout. Error in estimating reg ional ventilation from inert gas washout is small when the poorly ventilated region fills first and empties last, but appreciable when this region fills last and empties last.

Development of a Non-Invasive Dynamic Pulmonary Function Monitor

2012 ◽  
Vol 6 (2) ◽  
Author(s):  
Michael D. Sokoloff ◽  
Larry Bortner ◽  
Ralph J. Panos
Keyword(s):  
Pulmonary Function ◽  
Respiratory Diseases ◽  
Inert Gas ◽  
Airflow Limitation ◽  
Small Airways ◽  
Specific Measure ◽  
Gas Concentration ◽  
Non Invasive ◽  
Ventilation Inhomogeneity ◽  
Mass Spectrometer Sampling

Characterizing the complexity of airflow limitation in diagnosing and assessing disease severity in asthma, COPD, cystic fibrosis, and other respiratory diseases can help guide clinicians toward the most appropriate treatments. Current technologies allow obstructive lung disease to be measured with about 5%−10% precision. A noninvasive dynamic pulmonary function monitor (DPFM) can quantify ventilation inhomogeneities, such as those originating in partially blocked or constricted small airways, with 1% precision if inert gas concentrations can be measured accurately and precisely over three to four decades of sensitivity. We have studied the precision and linearity of a commercially available mass spectrometer, sampling the gas exhaled by a mechanical lung analog, mimicking a multibreath inert gas washout measurement. The root mean square deviation of the inert gas concentration measured for each “breath,” compared to the expected value for a purely exponential decay, is found to be about 1.1% over three decades of concentration. The corresponding overall impairment, a specific measure of ventilation inhomogeneity, is found to be about 0.2%, which indicates that were inhomogeneities observed, the corresponding impairment could be measured with 1% precision.

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

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