Rationale: Lung ultrasonography (US) may be useful for the prognostication of acute lung disease. Objectives: To assess whether the lung US score is associated with the severity of lung disease and may predict prolonged invasive mechanical ventilation (IMV) in critically ill children. Methods: Prospective observational multicenter study in children aged 1 month to 18 years who required respiratory support in the ICU. Children with chronic parenchymal lung disease were excluded. The lung US score was obtained at 12 hours and 48–72 hours after admission. Prolonged IMV was defined as at least 7 consecutive days. Correlation of the lung US score with oxygenation as well as its prognostic accuracy for prolonged IMV were investigated. Measurements and Main Results: A total of 538 children were included, and 62 (11.5%) required prolonged mechanical ventilation. In these subjects, the lung US score was higher at 12 (median, 24 [IQR, 19–26] vs. 8 [3–14]; P < 0.001) and 48–72 hours (16 [10.5–22.5] vs. 6 [3–11]; P < 0.001). At 12 hours, the lung US score correlated with oxygenation index (R2 = 0.435 [95% CI, 0.293–0.566]; ρ coefficient, −0.705; P < 0.001) and oxygen saturation index (R2 = 0.499 [95% CI, 0.370–0.613]; ρ coefficient, 0.651; P < 0.001). The lung US score at 12 hours had good accuracy in predicting prolonged IMV (area under the receiver operating characteristic curve [AUROC], 0.87; 95% CI, 0.81–0.93), and its use in a multivariable model had excellent accuracy in derivation (AUROC, 0.92; 95% CI, 0.89–0.95) and internal validation (AUROC, 0.91; 95% CI, 0.90–0.92). Conclusions: In critically ill children, the lung US score early after admission may predict prolonged IMV.

Generally, monitoring of hypoxemia has been always based on partial pressure of arterial oxygen to fraction of inspired oxygen ratio; recently it was confirmed a good correlation between this ratio and a non-invasive alternative ratio of oxygen saturation to fraction of inspired oxygen (SF ratio = SpO₂/FiO₂). The SF ratio has been studied and validated, especially in the intubated patients, however studies monitoring patients treated with non-invasive ventilation (NIV) are lacking. The aim of the study was to determine if the SF ratio is a reliable predictive factor for failure of NIV in pediatric patients diagnosed with hypoxemic acute respiratory failure due to pneumonia. A five year retrospective study with consecutive sampling of patients diagnosed with hypoxemic acute respiratory failure due to pneumonia, admitted to the pediatric intensive care unit in a university hospital and treated with NIV was conducted. Physiological and ventilator variables were collected before starting NIV and at 2, 8 and 12 hours of treatment, and the corresponding SF ratios calculated. Thirty-four patients were studied. NIV failed in seven patients. Significant differences in SF ratio were observed between the successful and unsuccessful patients at the onset, 2 and 12 hours of treatment. Multivariable analysis revealed the SF ratio at two hours to be an independent predictor of NIV failure (odds ratio = 0.96, 95% confidence intervals 0.93–0.99; P = 0.015). Area Under Receiver Operating Characteristic curve = 0.90 (95% confidence interval = 0.79 to 1.000), optimal cut off value for SF at 2 hours ≤ 189; sensitivity = 86%, specificity = 74%. In conclusion, the SF ratio of 189 or less at 2 hours of NIV seems to be useful for predicting NIV failure in this cohort.