A new method for noninvasive measurement of pulmonary gas exchange using expired gas

2018 ◽  
Vol 247 ◽  
pp. 112-115 ◽  
Author(s):  
John B. West ◽  
G. Kim Prisk
Keyword(s):  
Gas Exchange ◽  
Pulmonary Gas Exchange ◽  
New Method ◽  
Noninvasive Measurement ◽  
Expired Gas

Noninvasive Measurement of Pulmonary Gas Exchange during General Anesthesia

1980 ◽  
Vol 59 (4) ◽  
pp. 263???269 ◽  
Author(s):  
Frances E. Noe ◽  
Albert J. Whitty ◽  
Kenneth R. Davies ◽  
Barbara L. Wickham
Keyword(s):  
Gas Exchange ◽  
General Anesthesia ◽  
Pulmonary Gas Exchange ◽  
Noninvasive Measurement

A New Method Using Pulmonary Gas-Exchange Kinetics To Evaluate Efficacy of β-Blocking Agents in Patients With Dilated Cardiomyopathy

CHEST Journal ◽  
2003 ◽  
Vol 124 (3) ◽  
pp. 954-961 ◽  
Author(s):  
Yasuyo Taniguchi ◽  
Kenji Ueshima ◽  
Ikuo Chiba ◽  
Ikuo Segawa ◽  
Noboru Kobayashi ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Dilated Cardiomyopathy ◽  
Pulmonary Gas Exchange ◽  
New Method ◽  
Blocking Agents ◽  
Exchange Kinetics ◽  
Gas Exchange Kinetics

scholarly journals Deriving the arterial Po2 and oxygen deficit from expired gas and pulse oximetry

2019 ◽  
Vol 127 (4) ◽  
pp. 1067-1074 ◽  
Author(s):  
G. Kim Prisk ◽  
John B. West
Keyword(s):  
Gas Exchange ◽  
Pulse Oximetry ◽  
Base Excess ◽  
Pulmonary Gas Exchange ◽  
Oxygen Deficit ◽  
Dissociation Curve ◽  
Quiet Breathing ◽  
Arterial Blood ◽  
Expired Gas ◽  
The Ideal

The efficiency of pulmonary gas exchange is often assessed by the ideal alveolar-arterial partial pressure difference (A-aDO2). Through a combination of pulse oximetry and rapidly responding gas analyzers to measure the partial pressures of O2 and CO2 in expired gas, one can measure the oxygen deficit. Defined as the difference between the measured alveolar Po2 and the arterial Po2 calculated from [Formula: see text], the oxygen deficit is a substitute for the alveolar-arterial Po2 difference. The oxygen deficit is physiologically reasonable in that it increases with age in healthy subjects and is well correlated with the A-aDO2. To calculate arterial Po2 from saturation, the saturation should be below the very flat upper part of the O2-Hb dissociation curve; good estimates can be made provided the arterial O2 saturation is below ~95%. Since saturations at or above 95% imply reasonably well-maintained gas exchange efficiency, this limitation is of only minor concern. Calculations show that it is necessary to take into account the change in Po2 at a saturation of 50% of the O2-Hb dissociation curve based on the measured alveolar Pco2. As the measurement is designed to be noninvasive, determination of any base excess is not practical, but calculations show that the effect of assuming a zero base excess is modest, with a similar small effect from an abnormal body temperature. Taken together, these results show that a noninvasive assessment of pulmonary gas exchange efficiency can be obtained from subjects with below-normal arterial O2 saturations through a combination of expired O2 and CO2 measurements and [Formula: see text] made during quiet breathing. NEW & NOTEWORTHY The details and limitations of a noninvasive measurement of pulmonary gas exchange efficiency, the oxygen deficit, are described. The oxygen deficit, calculated from expired gas measurements made during quiet breathing coupled with pulse oximetry, is a good surrogate measurement of the ideal alveolar-arterial Po2 difference and does not require arterial blood gas sampling.

scholarly journals Measurements of pulmonary gas exchange efficiency using expired gas and oximetry: results in normal subjects

2018 ◽  
Vol 314 (4) ◽  
pp. L686-L689 ◽  
Author(s):  
John B. West ◽  
Daniel L. Wang ◽  
G. Kim Prisk
Keyword(s):  
Gas Exchange ◽  
Lung Disease ◽  
Normal Subjects ◽  
Mean Value ◽  
Pulmonary Gas Exchange ◽  
Oxygen Deficit ◽  
Arterial Blood ◽  
Age Related ◽  
Expired Gas ◽  
End Tidal

We are developing a novel, noninvasive method for measuring the efficiency of pulmonary gas exchange in patients with lung disease. The patient wears an oximeter, and we measure the partial pressures of oxygen and carbon dioxide in inspired and expired gas using miniature analyzers. The arterial Po2 is then calculated from the oximeter reading and the oxygen dissociation curve, using the end-tidal Pco2 to allow for the Bohr effect. This calculation is only accurate when the oxygen saturation is <94%, and therefore, these normal subjects breathed 12.5% oxygen. When the procedure is used in patients with hypoxemia, they breathe air. The Po2 difference between the end-tidal and arterial values is called the “oxygen deficit.” Preliminary data show that this index increases substantially in patients with lung disease. Here we report measurements of the oxygen deficit in 20 young normal subjects (age 19 to 31 yr) and 11 older normal subjects (47 to 88 yr). The mean value of the oxygen deficit in the young subjects was 2.02 ± 3.56 mmHg (means ± SD). This mean is remarkably small. The corresponding value in the older group was 7.53 ± 5.16 mmHg (means ± SD). The results are consistent with the age-related trend of the traditional alveolar-arterial difference, which is calculated from the calculated ideal alveolar Po2 minus the measured arterial Po2. That measurement requires an arterial blood sample. The present study suggests that this noninvasive procedure will be valuable in assessing the degree of impaired gas exchange in patients with lung disease.

Mechanisms of improvement in pulmonary gas exchange during isovolemic hemodilution

1999 ◽  
Vol 87 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Steven Deem ◽  
Richard G. Hedges ◽  
Steven McKinney ◽  
Nayak L. Polissar ◽  
Michael K. Alberts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fractal Dimension ◽  
Gas Exchange ◽  
Spatial Correlation ◽  
Pulmonary Blood Flow ◽  
Minute Ventilation ◽  
Flow Distribution ◽  
Pulmonary Gas Exchange ◽  
Normal Lung ◽  
Blood Flow Distribution

Severe anemia is associated with remarkable stability of pulmonary gas exchange (S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson. J. Appl. Physiol. 83: 240–246, 1997), although the factors that contribute to this stability have not been studied in detail. In the present study, 10 Flemish Giant rabbits were anesthetized, paralyzed, and mechanically ventilated at a fixed minute ventilation. Serial hemodilution was performed in five rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; five rabbits were followed over a comparable time. Ventilation-perfusion (V˙a/Q˙) relationships were studied by using the multiple inert-gas-elimination technique, and pulmonary blood flow distribution was assessed by using fluorescent microspheres. Expired nitric oxide (NO) was measured by chemiluminescence. Hemodilution resulted in a linear fall in hematocrit over time, from 30 ± 1.6 to 11 ± 1%. Anemia was associated with an increase in arterial [Formula: see text] in comparison with controls ( P < 0.01 between groups). The improvement in O2 exchange was associated with reducedV˙a/Q˙heterogeneity, a reduction in the fractal dimension of pulmonary blood flow ( P = 0.04), and a relative increase in the spatial correlation of pulmonary blood flow ( P = 0.04). Expired NO increased with anemia, whereas it remained stable in control animals ( P < 0.0001 between groups). Anemia results in improved gas exchange in the normal lung as a result of an improvement in overallV˙a/Q˙matching. In turn, this may be a result of favorable changes in pulmonary blood flow distribution, as assessed by the fractal dimension and spatial correlation of blood flow and as a result of increased NO availability.

Pulmonary Gas Exchange in Candidates for Surgical Treatment of Ischaemic Heart Disease

Respiration ◽  
1978 ◽  
Vol 35 (3) ◽  
pp. 136-147 ◽  
Author(s):  
P. Jebavý ◽  
J. Fabián ◽  
M. Henzlová ◽  
A. Belán
Keyword(s):  
Heart Disease ◽  
Surgical Treatment ◽  
Gas Exchange ◽  
Ischaemic Heart Disease ◽  
Pulmonary Gas Exchange

Pulmonary Gas Exchange and Oxygen Uptake During Exercise in Patients with Type 1 Diabetes Mellitus

1992 ◽  
Vol 9 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Th. Wanke ◽  
D. Formanek ◽  
M. Auinger ◽  
H. Zwick ◽  
K. Irsigler
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Type 1 Diabetes Mellitus ◽  
Pulmonary Gas Exchange
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