A novel method to measure regional muscle blood flow continuously using NIRS kinetics information

Dynamic Medicine

Table 1 Parameters for simulation in the resting arm finger flexor muscles

Term	Definition	Values	Unit	comments
THb	total hemoglobin ([HbO2] + [Hb])	98.1 ± 9.3	μM/kg	1
[HbO₂]	total HbO₂	62.3 ± 6.0	μM/kg	1
[HbO₂]_a	arterial HbO₂	27.7	μM/kg	2
[HbO₂]_v	venous HbO₂	34.6	μM/kg	2
[Hb]	total deoxyhemoglobin	35.8 ± 4.3	μM/kg	1
O₂	O₂ consumption	0.185 ± 0.012	μMHbO₂/sec/kg	1
Q_a, Q_v	arterial and venous blood flow	0.276	μMTHb/sec/kg	3
S_aO₂	arterial saturation	100	%	4
S_vO₂	venous saturation	49.1	%	5
StO₂	tissue saturation	63.5 ± 2.1	%	1
a/v ratio	arterial venous blood volume ratio	28.3%/71.7%	%/%	2

Comment 1. These values are from NIR measurements using IQ system (mean ± standard error, n = 9).
Comment 2. These are calculated from S_vO₂ and S_tO₂ which gives arterial venous blood volume ratio of 28.3%/71.7%.
Comment 3. The blood flow is calculated from Eqs. 4–5.
Comment 4. S_aO₂ is assumed 100%.
Comment 5. S_vO₂ is assumed 49.1% ([24]).