Table 4– Calculations of membrane diffusing capacity for nitric oxide (D_M,NO), membrane diffusing capacity for carbon monoxide (D_M,CO) and pulmonary capillary volume (V_c); see Appendix for explanation and commentary

	Data set	D_M,NO mL·min⁻¹·mmHg⁻¹	D_M,CO^# mL·min⁻¹·mmHg⁻¹	1/D_M,CO mL⁻¹·min·mmHg	1/Θ_bl,CO·V_c mL⁻¹·min· mmHg	1/Θ_bl,CO mL⁻¹·min mmHg·mL⁻¹	V_c mL	*1/Θ_bl,CO·V_c/(1/T_L,CO) ∼ T_L,CO red blood cell resistance %*	Comment
NO blood resistance=0 1/Θ_bl,NO = 0
	A	144	73	0.0137	0.0173	1.31	76	55	Most used Θ_bl value but at pH 8.0 [3]
	B	144	73	0.0137	0.0173	1.71	99	55	Θ_bl value at pH 7.4 [15]
	C	144	73	0.0137	0.0173	0.82	47	55	Θ_bl thin film exps [16]
Finite NO blood resistance (1/Θ_bl,NO·V_c)/(1/T_L,NO) = 37%
	D	230	117	0.0086	0.0224	1.31	58	72	D_M,NO from [10]:
	E	230	117	0.0086	0.0224	1.71	76	72	D_M,NO from [10]:
	F	230	117	0.0086	0.0224	0.82	37	72	D_M,NO from [10]:
	G	230			0.0026^¶	0.22⁺	88	36^§	From Roughton–Forster equation and 1/D_M,NO and 1/Θ_bl,NO

The calculations for D_M,CO and V_c were derived from “normal, resting” transfer factor of the lung for NO (T_L,NO; 144 mL·min⁻¹·mmHg⁻¹) and T_L,NO/T_L,CO ratio (4.5) [1, 12, 19, 22–26] (T_L,CO=32 mL min⁻¹ mmHg⁻¹); for situations where NO uptake blood resistance is zero (1/D_M,NO = 1/T_L,NO) or finite (1/D_M,NO<1/T_L,NO). D_M,CO derived from D_M,NO for α = 1.97 (NO/CO diffusivity ratio), and V_c derived via Roughton–Forster equation 1 for different experimental values of the blood resistance to carbon monoxide transfer (1/Θ_bl,CO; at P_O₂ 100 mmHg). Multiply by three to convert to SI units (mmol·min⁻¹·kPa⁻¹1) from mL·min⁻¹·mmHg⁻¹.^#: α = 1.97; ^¶: 1/Θ_bl,NO·V_c was used not 1/Θ_bl,CO·V_c; ⁺: 1/Θ_bl,NO was used not 1/Θ_bl,CO; ^§: ∼NO red blood cell resistance % was used not T_L,CO red blood cell resistance %.