TABLE 1.

Calculation of Effective Fio₂, Step 1

Flow, L/min	Factor With Weight of
Flow, L/min	0.7 kg	1.0 kg	1.25 kg	1.5 kg	2 kg	2.5 kg	3 kg	3.5 kg	4 kg
0.01	1	1	1	1	1	0	0	0	0
0.03 (1/32)	4	3	2	2	2	1	1	1	1
0.06 (1/16)	9	6	5	4	3	2	2	2	2
0.125 (1/8)	18	12	10	8	6	4	4	4	4
0.15	21	15	12	10	8	6	5	4	4
0.25 (1/4)	36	25	20	17	13	10	8	7	6
0.5 (1/2)	71	50	40	33	25	20	17	14	13
0.75 (3/4)	100	75	60	50	38	30	25	21	19
1.0 (1.0)	100	100	80	67	50	40	33	29	25
1.25	100	100	100	83	63	50	42	36	31
1.5	100	100	100	100	75	60	50	43	38
2.0	100	100	100	100	100	80	67	57	50
3.0	100	100	100	100	100	100	100	86	75

Adapted from equations 3 and 4 in ref ¹. The rule of thumb (implicit in the table) is that, for most infants in the STOP-ROP study, if flow (in liters per minute) exceeds body weight (in kilograms), then the effective Fio₂ equals the nasal cannula oxygen concentration.