TABLE 2.
Hypoxemia Severity Assessment
| Metric (95% CI) | Spo2 ≤ 97% | Spo2 > 97% | ||||
|---|---|---|---|---|---|---|
| OI Using OSI | OI Using ePao2 | p | OI Using OSI | OI Using ePao2 | p | |
| Weighted kappa | 0.60 (0.58–0.62) | 0.79 (0.77–0.81) | < 0.001 | 0.52 (0.50–0.54) | 0.58 (0.56–0.59) | < 0.001 |
| Intraclass correlation coefficient | 0.91 (0.89–0.92) | 0.93 (0.92–0.94) | 0.029 | 0.62 (0.60–0.64) | 0.72 (0.69–0.75) | < 0.001 |
| Mean absolute error | 3.68 (3.57–3.79) | 1.90 (1.80–2.01) | < 0.001 | 3.58 (3.47–3.68) | 1.60 (1.54–1.67) | < 0.001 |
| Coefficient of determination (R2) | 0.84 (0.82–0.86) | 0.87 (0.85–0.89) | 0.043 | 0.51 (0.48–0.55) | 0.55 (0.51–0.59) | 0.170 |
| Slope | 0.81 (0.78–0.84) | 1.02 (0.98–1.06) | < 0.001 | 0.42 (0.39–0.44) | 0.93 (0.88–0.99) | < 0.001 |
| Fixed bias | 2.01 (1.85–2.17) | 0.15 (0.02–0.28) | < 0.001 | –0.48 (–0.63 to –0.34) | 0.13 (0.05–0.21) | < 0.001 |
| Proportional bias | –0.12 (–0.16 to –0.09) | 0.09 (0.06–0.13) | < 0.001 | –0.61 (–0.67 to –0.55) | 0.26 (0.20–0.34) | < 0.001 |
| Upper and lower limits of agreements difference | 0.32 (0.30–0.34) | 0.25 (0.23–0.28) | < 0.001 | 0.29 (0.28–0.31) | 0.16 (0.15–0.18) | < 0.001 |
| AUROC for mild hypoxemia (OI ≥ 4) | 0.92 (0.91–0.93) | 0.93 (0.92–0.94) | 0.122 | 0.87 (0.86–0.88) | 0.88 (0.87–0.89) | 0.052 |
| AUROC for severe hypoxemia (OI ≥ 16) | 0.98 (0.97–0.98) | 0.98 (0.98–0.99) | 0.055 | 0.96 (0.95–0.97) | 0.96 (0.95–0.97) | 0.986 |
AUROC = area under the receiving operating characteristic curve, ePao2 = estimated Pao2, OI = oxygenation index, OSI = oxygenation saturation index.