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Table 3 FiO 2 adjustment following ABG analysis and its effects on oxygenation measured in the next ABG

From: Self-reported attitudes versus actual practice of oxygen therapy by ICU physicians and nurses

PaO2(%) Adjustment of FiO2(%) Successive PaO2
[n = 61,073]
[n = 107,888] [n = 62,222] Higher Unchanged Lower
(Delta PaO2) (Delta PaO2)
<7 kPa (1.2) Higher (34.7) 96.6% (+5.3) 0.4% 3.0% (−0.5)
Unchanged (46.9) 87.4% (+5.6) 3.2% 9.4% (−0.6)
Lower (18.4) 95.1% (+7.9) 2.4% 2.5% (−0.9)
7 to 10 kPa (25.3) Higher (27.9) 76.3% (+3.1) 2.7% 21.0% (−0.9)
Unchanged (56.0) 66.3% (+2.0) 4.3% 29.4% (−0.8)
Lower (16.1) 61.3% (+2.6) 3.6% 35.1% (−1.0)
>10 kPa (73.4) Higher (10.8) 48.6% (+4.6) 2.1% 49.3% (−3.1)
Unchanged (62.0) 44.7% (+2.1) 3.1% 52.2% (−2.3)
Lower (27.2) 23.5% (+2.4) 1.7% 74.8% (−4.6)
Total (100) - 46.3% (+2.6) 2.7% 51.0% (−2.9)
  1. Data presented as percentages of total and irrespective of adjustment of other ventilator settings (e.g., PEEP, I/E ratio). PaO2 = any recorded PaO2 stratified by self-reported ranges; successive PaO2 = PaO2 from successively registered ABG sample; Delta = mean difference between two successive ABG samples; Higher = increased FiO2 (column 2) or PaO2 (column 3), higher than previous level; unchanged = FiO2 or PaO2 equal to previous level; lower = decreased FiO2 or PaO2, lower than previous level. A total of 62,222 PaO2 measurements from 3,791 patients (57.7% of all 107,888 ABG samples) in the database is followed by an adjustment of ventilator settings, and 98.2% of PO2 measurements is followed by a successive PO2 measurement (n = 61,073) in the same patient when adjustment of FiO2 is also measured.