Some theoretical problems connected with gas-exchange mechanisms in artificial hearts communication 1. Determination of minimum priming volume for foam-film type oxygenators

1968 ◽  
Vol 2 (3) ◽  
pp. 134-135
Author(s):  
N. A. Super ◽  
V. S. Kasulin
Keyword(s):  
Gas Exchange ◽  
Film Type ◽  
Priming Volume ◽  
Artificial Hearts ◽  
Foam Film

Catecholamine and blood lactate responses to incremental rowing and running exercise

1994 ◽  
Vol 76 (3) ◽  
pp. 1144-1149 ◽  
Author(s):  
A. Weltman ◽  
C. M. Wood ◽  
C. J. Womack ◽  
S. E. Davis ◽  
J. L. Blumer ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Blood Lactate ◽  
Venous Catheter ◽  
Incremental Exercise ◽  
Plasma Epinephrine ◽  
O2 Uptake ◽  
Running Exercise ◽  
Rowing Ergometer ◽  
Per Se

Ten collegiate rowers performed discontinuous incremental exercise to their tolerable limit on two occasions: once on a rowing ergometer and once on a treadmill. Ventilation and pulmonary gas exchange were monitored continuously, and blood was sampled from a venous catheter located in the back of the hand or forearm for determination of blood lactate ([La]) and plasma epinephrine ([Epi]) and norepinephrine ([NE]) concentrations. Thresholds for lactate (LT), epinephrine (Epi-T), and norepinephrine (NE-T) were determined for each subject under each condition and defined as breakpoints when plotted as a function of O2 uptake (VO2). For running, LT (3.76 +/- 0.18 l/min) was lower (P < 0.05) than Epi-T (4.35 +/- 0.14 l/min) and NE-T (4.04 +/- 0.19 l/min). For rowing, LT (3.35 +/- 0.16 l/min) was lower (P < 0.05) than Epi-T (3.72 +/- 0.22 l/min) and NE-T (3.70 +/- 0.18 l/min) and was lower (P < 0.05) than LT for running. Within each mode of exercise, Epi-T and NE-T did not differ. Because LT occurred at a significantly lower VO2 than either Epi-T or NE-T, we conclude that catecholamine thresholds, per se, were not the cause of LT. However, for both modes of exercise LT occurred at a plasma [Epi] of approximately 200–250 pg/ml (rowing, 221 +/- 48 pg/ml; running, 245 +/- 45 pg/ml); these concentrations are consistent with the plasma [Epi] reported necessary for eliciting increments in blood [La] during Epi infusion at rest. Plasma [NE] at LT differed significantly between modes (rowing, 820 +/- 127 pg/ml; running, 1,712 +/- 217 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Breath-by-breath variation of FRC: effect on VO2 and VCO2 measured at the mouth

1979 ◽  
Vol 46 (6) ◽  
pp. 1122-1126 ◽  
Author(s):  
H. U. Wessel ◽  
R. L. Stout ◽  
C. K. Bastanier ◽  
M. H. Paul
Keyword(s):  
Steady State ◽  
Gas Exchange ◽  
Gas Flow ◽  
Co2 Gas ◽  
Mean Values ◽  
Gas Uptake ◽  
Source Data ◽  
Alveolar Level ◽  
Age Range

We examined breath-by-breath (B-B) variations of FRC (delta FRC) and their effect on measured O2 and CO2 gas exchange in 52 2- to 4-min segments of continuous air breathing obtained in 29 patients (age range 6--50 yr). Respiratory frequency ranged from 13 to 43 breaths/min, VE from 6.7 to 22.5 l/min (BTPS), and expired VT from 234 to 1,370 ml (BTPS). Computer analysis was based on the following source data measured at the mouth: inspired (VI) and expired (VE) gas flow, FN2, FO2 and FCO2. The analysis provides B-B evaluation of VI, VE, delta FRC in terms of VN2, and VO2 and VCO2 at the mouth and at the alveolar level, i.e., after correction for delta FRC. Significant B-B variations of FRC were found in all studies. delta FRC ranged from +360 to -360 ml (BTPS). For single respiratory cycles VI - VE is primarily a function of N2 exchange at the mouth (VMN2). VO2 and VCO2, uncorrected for delta FRC, are significantly more dispersed about mean values than the corrected gas uptakes (P less than 0.0005). The data support the view that the assumption of VIN2 = VEN2 is invalid for single respiratory cycles. Determination of breath-by-breath VO2 and VCO2 should therefore, not be based on steady-state gas uptake equations. It requires measurement of both inspired and expired breath volumes and evaluation of N2 gas exchange.

New Fiber Configuration for Intravenous Gas Exchange

2005 ◽  
Vol 28 (3) ◽  
pp. 244-250 ◽  
Author(s):  
G.F. Cattaneo ◽  
H. Reul
Keyword(s):  
Gas Exchange ◽  
Vena Cava ◽  
Fiber Surface ◽  
Blood Oxygenation ◽  
The Body ◽  
Fiber Density ◽  
Acute Lung Failure ◽  
Priming Volume ◽  
Lung Failure ◽  
Twisted Shape

Implantation of a membrane oxygenator (IO) into the vena cava for blood oxygenation in patients with acute lung failure has been researched for the last 25 years. Compared to the extra corporeal blood oxygenation, where blood is handled outside the body, IO doesn't present tubes, housings or heat exchangers, thus reducing considerably blood contact surface and setting priming volume to zero. Otherwise, restricted space in the vena cava and unadvantageous blood flow conditions represent so far a limitation for sufficient gas exchange. A new fiber configuration for intravenous use is being developed, which increases the implantable fiber surface and enhances gas exchange due to the increased blood convection. This is made possible by new fiber bundles, which are free to slide on a catheter and after implantation assume a twisted shape characterized by high homogeneity and fiber density.

DETERMINATION OF GAS EXCHANGE CAPACITY OF SOME BREBA FIG CULTIVARS

2008 ◽  
pp. 117-122 ◽  
Author(s):  
H.Z. Can ◽  
K.B. Meyvacı ◽  
B. Balci
Keyword(s):  
Gas Exchange ◽  
Exchange Capacity

Determination of the gas exchange rate in whitecaps using measurements of the bubble concentration

1991 ◽  
Vol 2 (3) ◽  
pp. 221-225 ◽  
Author(s):  
V. S. Bezzabotnov ◽  
A. Kh. Degterev ◽  
V. N. Eremeev
Keyword(s):  
Exchange Rate ◽  
Gas Exchange ◽  
Gas Exchange Rate

Non-invasive automatic determination of anaerobic threshold using double gas exchange parameters

1990 ◽  
Vol 31 (2) ◽  
pp. 73-79
Author(s):  
Yoshiyuki Fukuba ◽  
Sachio Usui ◽  
Koichi Iwanaga ◽  
Takashige Koba ◽  
Masaki Munaka
Keyword(s):  
Gas Exchange ◽  
Anaerobic Threshold ◽  
Automatic Determination ◽  
Gas Exchange Parameters ◽  
Non Invasive ◽  
Exchange Parameters

scholarly journals An Inexpensive, Whole-plant, Open Gas-exchange System for the Measurement of Photosynthesis in Potted Woody Plants

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 779E-779
Author(s):  
David P. Miller ◽  
G. Stanley Howell ◽  
James A. Flore
Keyword(s):  
Gas Exchange ◽  
Abiotic Factors ◽  
Incident Radiation ◽  
Single Leaf ◽  
Whole Plant ◽  
Plant Assimilation ◽  
Gas Exchange System ◽  
Source Sink ◽  
Short Time

The measurement of whole-plant CO2 uptake integrates leaf-to-leaf variability, which arises from such sources as angle of incident radiation, source/sink relationships, age, and biotic or abiotic factors. Respiration of above-ground vegetative and reproductive sinks is also integrated into the final determination of whole-plant CO2 assimilation. While estimates of whole-plant CO2 uptake based on single-leaf determinations have been used, they do not accurately reflect actual whole-plant assimilation. Chambers were constructed to measure gas exchange of entire potted grapevines. The design and construction are simple, inexpensive, and easy to use, allowing for the measurement of many plants in a relatively short time. This enables the researcher to make replicated comparisons of the whole-plant CO2 assimilation of various treatments throughout the growing season. While CO2 measurement was the focus of this project, it is also possible to measure whole-plant transpiration with this system.

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