Table 1_External validation of predictive equations for determining the need for in-flight oxygen supplementation in patients with respiratory disease.pdf

Significant correlations between predicted in-flight PaO₂ and HCT PaO₂ were observed (ρ = 0.48 for E1 and E2 to 0.84 for E5; all p ≤ 0.001), but diagnostic performance remained limited. Across all patients, predictive equations demonstrated high specificity (76% for E2 to 98% for E6) but inadequate sensitivity (11% for E6 to 67% for E2) for identifying patients requiring supplemental oxygen. Cohen’s κ coefficients ranged from 0.07 (95% CI, −0.06 to 0.20) for E4 to 0.43 (95% CI, 0.27–0.59) for E2.

Areas under the ROC curve ranged from 0.71 (95% CI, 0.62–0.81) for E4 to 0.79 (95% CI, 0.70–0.88) for E1.</p>Conclusions<p>In this large external validation study, currently available predictive equations demonstrated insufficient diagnostic performance to safely replace HCT for determining the need for in-flight oxygen supplementation. Although several equations showed moderate to strong agreement with measured HCT PaO₂, inadequate sensitivity resulted in clinically important misclassification of patients requiring supplemental oxygen.

HCT should remain the reference standard for evaluating patients in whom the need for in-flight oxygen supplementation is uncertain.</p>