Pulmonary Membrane Diffusing Capacity and Capillary Blood Volume Measured During Exercise From Nitric Oxide Uptake

Tamhane, Rahul M.; Johnson, Robert L.; Hsia, Connie C. W.

doi:10.1378/chest.120.6.1850

Cited by 118 publications

(159 citation statements)

References 22 publications

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“…This technique requires the subject to nearly empty the rebreathe bag without a complete inspiratory collapse of the bag. To prevent forceful collapse of the bag (which could alter breathing pattern or pressurize the gas sample line, influencing the measured gas concentration values), the rebreathe bag is filled to a volume that is at least as big as the tidal breath, although some laboratories use volumes as large as the subject's inspiratory capacity (31). A recent innovation for precisely matching bag volume to the subject is to use a double-switching valve, allowing the subject to freely draw from an inspired bag on the first breath and subsequently turning into the rebreathe bag (31).…”

Section: Discussionmentioning

confidence: 99%

“…To prevent forceful collapse of the bag (which could alter breathing pattern or pressurize the gas sample line, influencing the measured gas concentration values), the rebreathe bag is filled to a volume that is at least as big as the tidal breath, although some laboratories use volumes as large as the subject's inspiratory capacity (31). A recent innovation for precisely matching bag volume to the subject is to use a double-switching valve, allowing the subject to freely draw from an inspired bag on the first breath and subsequently turning into the rebreathe bag (31). Although, in theory, this method should allow more appropriate matching of bag volume, even this method could result in an uncomfortable mismatch between bag and tidal volume, if the first breath were not representative of the subject's average breathing pattern.…”

Section: Discussionmentioning

confidence: 99%

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An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

Snyder¹,

Johnson

Beck³

2005

Journal of Applied Physiology

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CO,OC) and the DLCO,RB methods at rest and during exercise (25, 50, and 75% of peak work) in 11 healthy subjects [mean age ϭ 34 yr (SD 11)]. Both DL CO,OC and DLCO,RB increased linearly with cardiac output and external work. There was a good correlation between DL CO,OC and DLCO,RB for rest and exercise (mean of individual r 2 ϭ 0.88, overall r 2 ϭ 0.69, slope ϭ 0.97). DLCO,OC and DLCO,RB were similar at rest and during exercise [e.g., rest ϭ 27.2 (SD 5.8) vs. 29.3 (SD 5.2), and 75% peak work ϭ 44.0 (SD 7.0) vs. 41.2 ml⅐min Ϫ1 ⅐mmHg Ϫ1 (SD 6.7) for DL CO,OC vs. DLCO,RB]. The coefficient of variation for repeat measurements of DL CO,OC was 7.9% at rest and averaged 3.9% during exercise. These data suggest that the DL CO,OC method is a reproducible, well-tolerated alternative for determining DL CO, particularly during exercise. The method is linearly associated with cardiac output, suggesting increased alveolar-capillary recruitment, and values were similar to the traditional rebreathe method.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

Snyder¹,

Johnson

Beck³

2005

Journal of Applied Physiology

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“…The TL,NO/TL,CO ratio decreased by an average of 9% (range -2 to -16%). DM and Vc both increased on exercise [17], but TL,NO will not share the increase in Vc caused by capillary recruitment and distension, so the TL,NO/TL,CO ratio will fall.…”

Section: Ageingmentioning

confidence: 96%

“…Another variable is the DM,NO/DM,CO ratio (a) which, on physical principles, should be in the range 1.93-1.97. Investigators have ''forced'' a to 2.42 [17] or 2.08-2.26 [18] to give a ''best fit'' with the DM,CO and Vc calculated from the oxygen two-step Roughton-Forster TL,CO method. Since a is defined as the physical diffusivity ratio of NO/CO, this approach cannot be correct physiologically.…”

Section: Dmco and Vc From Simultaneous Single Breathmentioning

confidence: 99%

TheT_L,NO/T_L,COratio in pulmonary function test interpretation

Hughes

Lee

2012

Eur Respir J

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The transfer factor of the lung for nitric oxide (TL,NO) is a new test for pulmonary gas exchange. The procedure is similar to the already well-established transfer factor of the lung for carbon monoxide (TL,CO). Physiologically, TL,NO predominantly measures the diffusion pathway from the alveoli to capillary plasma. In the Roughton-Forster equation, TL,NO acts as a surrogate for the membrane diffusing capacity (DM). The red blood cell resistance to carbon monoxide uptake accounts for ,50% of the total resistance from gas to blood, but it is much less for nitric oxide.TL,NO and TL,CO can be measured simultaneously with the single breath technique, and DM and pulmonary capillary blood volume (Vc) can be estimated. TL,NO, unlike TL,CO, is independent of oxygen tension and haematocrit. The TL,NO/TL,CO ratio is weighted towards the DM/Vc ratio and to a; where a is the ratio of physical diffusivities of NO to CO (a51.97). The TL,NO/TL,CO ratio is increased in heavy smokers, with and without computed tomography evidence of emphysema, and reduced in the voluntary restriction of lung expansion; it is expected to be reduced in chronic heart failure. The TL,NO/TL,CO ratio is a new index of gas exchange that may, more than derivations from them of DM and Vc with their in-built assumptions, give additional insights into pulmonary pathology.

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“…Therefore, diffusing capacity of the lung for nitric oxide (DL,NO) equals the membrane diffusing capacity for NO (Dm,NO), and is independent of Vc and haemoglobin concentration [8]. Others have made the same assumption that (1/HNO) is negligible [9][10][11][12][13][14], and it was recently determined that a nonzero 1/ HNO would not be able to explain their experimental data [12]. Therefore, these data suggest that DL,NO is a good measure of Dm,NO.…”

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confidence: 99%

A small amount of inhaled nitric oxide does not increase lung diffusing capacity

Zavorsky

Murias²

2006

Eur Respir J

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The aim of the present study was to determine: 1) whether 40-50 ppm nitric oxide (NO) increases diffusing capacity of the lung for NO (DL,NO) and carbon monoxide (DL,CO), membrane diffusing capacity for CO (Dm,CO) and pulmonary capillary blood volume (Vc); 2) the actual number of tests required to provide a reasonable estimate of DL,NO, DL,CO, Dm,CO and Vc; and 3) repeatability of these parameters using the single-breath DL,NO-DL,CO method.In total, 31 subjects performed five single-breath hold manoeuvres at rest, inhaling 43¡3 ppm NO together with a standard diffusion mixture.DL,NO (Dm,CO) remained unchanged from the first to fifth trial. However, compared with the first trial, DL,CO and Vc had decreased by the fourth (-4¡5%; 95% confidence interval (CI)5-5--2%) and third trial (-5¡7%; 95% CI5-7--2%), respectively. Repeatability over five trials was 17, 3 and 7 mL?min -1?mmHg -1 for DL,NO, DL,CO and Dm,CO, respectively, and 13 mL for Vc when Dm,CO5DL,NO/2.42.In conclusion, nitric oxide inhaled during sequential single-breath manoeuvres has no effect on diffusing capacity of the lung for nitric oxide and, thus, membrane diffusing capacity for carbon monoxide. Since more than two and three trials will lower pulmonary capillary blood volume and diffusing capacity of the lung for carbon monoxide, respectively, the average value of only two properly performed trials is suggested.

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Pulmonary Membrane Diffusing Capacity and Capillary Blood Volume Measured During Exercise From Nitric Oxide Uptake

Cited by 118 publications

References 22 publications

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

TheT_L,NO/T_L,COratio in pulmonary function test interpretation

A small amount of inhaled nitric oxide does not increase lung diffusing capacity

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Pulmonary Membrane Diffusing Capacity and Capillary Blood Volume Measured During Exercise From Nitric Oxide Uptake

Cited by 118 publications

References 22 publications

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

TheTL,NO/TL,COratio in pulmonary function test interpretation

A small amount of inhaled nitric oxide does not increase lung diffusing capacity

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TheT_L,NO/T_L,COratio in pulmonary function test interpretation