Calculating alveolar capillary conductance and pulmonary capillary blood volume: comparing the multiple- and single-inspired oxygen tension methods

Ceridon, Maile L.; Beck, Kenneth C.; Olson, Thomas P.; Bilezikian, Jordan A; Johnson, Bruce D.

doi:10.1152/japplphysiol.01411.2009

Cited by 42 publications

(58 citation statements)

References 32 publications

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“…This value is derived from the solubility and the molecular weight of the gases (3). Others have determined a ratio of 2.2 to 2.4 (9,47). It has been determined that a ratio of Fig.…”

Section: Discussionmentioning

confidence: 99%

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Bisschop

Martinot

Leurquin‐Sterk³

et al. 2012

Journal of Applied Physiology

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de Bisschop C, Martinot J, Leurquin-Sterk G, Faoro V, Guénard H, Naeije R. Improvement in lung diffusion by endothelin A receptor blockade at high altitude. J Appl Physiol 112: 20 -25, 2012. First published October 6, 2011 doi:10.1152/japplphysiol.00670.2011.-Lung diffusing capacity has been reported variably in high-altitude newcomers and may be in relation to different pulmonary vascular resistance (PVR). Twenty-two healthy volunteers were investigated at sea level and at 5,050 m before and after random double-blind intake of the endothelin A receptor blocker sitaxsentan (100 mg/day) vs. a placebo during 1 wk. PVR was estimated by Doppler echocardiography, and exercise capacity by maximal oxygen uptake (V O2 max). The diffusing capacities for nitric oxide (DLNO) and carbon monoxide (DLCO) were measured using a single-breath method before and 30 min after maximal exercise. The membrane component of DLCO (Dm) and capillary volume (Vc) was calculated with corrections for hemoglobin, alveolar volume, and barometric pressure. Altitude exposure was associated with unchanged DLCO, DLNO, and Dm but a slight decrease in Vc. Exercise at altitude decreased DLNO and Dm. Sitaxsentan intake improved V O2 max together with an increase in resting and postexercise DLNO and Dm. Sitaxsentan-induced decrease in PVR was inversely correlated to DLNO. Both DLCO and DLNO were correlated to V O2 max at sea level (r ϭ 0.41-0.42, P Ͻ 0.1) and more so at altitude (r ϭ 0.56 -0.59, P Ͻ 0.05). Pharmacological pulmonary vasodilation improves the membrane component of lung diffusion in high-altitude newcomers, which may contribute to exercise capacity. altitude; hypoxia; lung diffusion; gas exchange; exercise capacity; pulmonary vascular resistance; pulmonary capillary pressure; pulmonary hypertension BOTH THE MEMBRANE AND THE capillary components of lung diffusing capacity have been shown to be increased in highaltitude residents (10,13,15,25). Increased lung diffusing capacity at high altitude allows for the preservation of gas exchange in the presence of a decreased ventilatory response at exercise (15). High-altitude newcomers do not benefit from this adaptation (10,15,25) and, accordingly, depend on increased ventilation to maintain pulmonary gas exchange (15,45).Previous studies on lung diffusing capacity at high altitudes calculated the membrane and capillary components of alveolocapillary transfer of carbon monoxide (CO) using measurements at ambient air and increased inspired PO 2 (10,13,15,25). This approach rests on the PO 2 dependence of , the blood's specific transfer conductance of CO, in the Roughton and Forster equation, which states that 1/DL CO ϭ 1/Dm ϩ 1/ Vc where DL CO is the diffusing capacity of the lung for CO, Dm its membrane component, and Vc the capillary blood volume (37). Thus changing as by increasing or decreasing inspired PO 2 allows for the calculation of Dm and Vc from a simple system of two equations with two unknowns. However, changing inspired PO 2 might also change pulmonary vascular tone, cardiac output, ...

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“…This value is derived from the solubility and the molecular weight of the gases (3). Others have determined a ratio of 2.2 to 2.4 (9,47). It has been determined that a ratio of Fig.…”

Section: Discussionmentioning

confidence: 99%

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Bisschop

Martinot

Leurquin‐Sterk³

et al. 2012

Journal of Applied Physiology

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“…Others have shown that this correction factor ranges from 1.93 to 2.49; specifically, more recent work by Ceridon et al has demonstrated that a correction factor of 2.11 is most appropriate with exercise studies and as such used in this study (Ceridon et al 2010).…”

Section: Protocolmentioning

confidence: 95%

Glycemic control influences lung membrane diffusion and oxygen saturation in exercise-trained subjects with type 1 diabetes

et al. 2010

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Lung diffusing capacity (DLCO) is influenced by alveolar-capillary membrane conductance (D (M)) and pulmonary capillary blood volume (V (C)), both of which can be impaired in sedentary type 1 diabetes mellitus (T1DM) subjects due to hyperglycemia. We sought to determine if T1DM, and glycemic control, affected DLNO, DLCO, D (M), V (C) and SaO(2) during maximal exercise in aerobically fit T1DM subjects. We recruited 12 T1DM subjects and 18 non-diabetic subjects measuring DLNO, DLCO, D (M), and V (C) along with SaO(2) and cardiac output (Q) at peak exercise. The T1DM subjects had significantly lower DLCO/Q and D (M)/Q with no difference in Q, DLNO, DLCO, D (M), or V (C) (DLCO/Q = 2.1 ± 0.4 vs. 1.7 ± 0.3, D (M)/Q = 2.8 ± 0.6 vs. 2.4 ± 0.5, non-diabetic and T1DM, p < 0.05). In addition, when considering all subjects there was a relationship between DLCO/Q and SaO(2) at peak exercise (r = 0.46, p = 0.01). Within the T1DM group, the optimal glycemic control group (HbA1c <7%, n = 6) had higher DLNO, DLCO, and D (M)/Q than the poor glycemic control subjects (HbA1c ≥ 7%, n = 6) at peak exercise (DLCO = 38.3 ± 8.0 vs. 28.5 ± 6.9 ml/min/mmHg, DLNO = 120.3 ± 24.3 vs. 89.1 ± 21.0 ml/min/mmHg, D (M)/Q = 3.8 ± 0.8 vs. 2.7 ± 0.2, optimal vs. poor control, p < 0.05). There was a negative correlation between HbA1c with DLCO, D (M) and D (M)/Q at peak exercise (DLCO: r = -0.70, p = 0.01; D (M): r = -0.70, p = 0.01; D (M)/Q: r = -0.68, p = 0.02). These results demonstrate that there is a reduction in lung diffusing capacity in aerobically fit athletes with T1DM at peak exercise, but suggests that maintaining near-normoglycemia potentially averts lung diffusion impairments.

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“…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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Calculating alveolar capillary conductance and pulmonary capillary blood volume: comparing the multiple- and single-inspired oxygen tension methods

Cited by 42 publications

References 32 publications

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Glycemic control influences lung membrane diffusion and oxygen saturation in exercise-trained subjects with type 1 diabetes

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

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Calculating alveolar capillary conductance and pulmonary capillary blood volume: comparing the multiple- and single-inspired oxygen tension methods

Cited by 42 publications

References 32 publications

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Improvement in lung diffusion by endothelin A receptor blockade at high altitude

Glycemic control influences lung membrane diffusion and oxygen saturation in exercise-trained subjects with type 1 diabetes

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

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Product

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About

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