SpO2/FiO2 as a predictor of high flow nasal cannula outcomes in children with acute hypoxemic respiratory failure

Impact of Surgical Mask Placement Over High-Flow Nasal Cannula on Oxygenation Parameters in COVID-19 Patients Experiencing Hypoxemic Respiratory Failure

BACKGROUND

During the COVID-19 pandemic, managing respiratory failure in critically ill patients has presented significant challenges. A high-flow nasal cannula (HFNC) has been established as an effective respiratory support modality, offering heated, humidified oxygen at high flow rates. However, concerns persist regarding the potential for aerosol dispersion and the risk of viral transmission, particularly in COVID-19. This study investigates the impact of surgical mask (3-ply surgical mask) placement over HFNC on oxygenation parameters in COVID-19 patients experiencing hypoxemic respiratory failure.

METHODS

A retrospective analysis of clinical data from a tertiary medical facility was conducted. The study included 35 patients with confirmed COVID-19 and moderate to severe hypoxemia. Oxygenation indices such as the SpO2/FiO2 (SF) ratio, flow rate, and the ratio of oxygen saturation index (ROX index) were monitored before and after the application of surgical masks over HFNC. Statistical analyses were performed to compare these parameters before and after surgical mask placement.

RESULTS

The adjunctive use of surgical masks over HFNC significantly improved oxygenation parameters compared to HFNC alone. Despite these improvements, there was no significant change in heart and respiratory rates, quick sequential organ failure assessment (qSOFA) scores, or Glasgow Coma Scale (GCS) levels. Subgroup analysis showed an increase in SF ratio ranging between 5.49% and 6.04% in patients with ROX indices, but these trends were not statistically significant.

CONCLUSION

This study provides preliminary evidence that surgical masks over HFNC may enhance oxygenation in critically ill COVID-19 patients with hypoxemic respiratory failure. These results underscore the potential importance of infection control measures in respiratory therapy during pandemics and suggest that further investigation in more extensive prospective studies is warranted.

Development and Validation of a Model for Endotracheal Intubation and Mechanical Ventilation Prediction in PICU Patients

OBJECTIVES

To develop and externally validate an intubation prediction model for children admitted to a PICU using objective and routinely available data from the electronic medical records (EMRs).

DESIGN

Retrospective observational cohort study.

SETTING

Two PICUs within the same healthcare system: an academic, quaternary care center (36 beds) and a community, tertiary care center (56 beds).

PATIENTS

Children younger than 18 years old admitted to a PICU between 2010 and 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical data was extracted from the EMR. PICU stays with at least one mechanical ventilation event (≥ 24 hr) occurring within a window of 1-7 days after hospital admission were included in the study. Of 13,208 PICU stays in the derivation PICU cohort, 1,175 (8.90%) had an intubation event. In the validation cohort, there were 1,165 of 17,841 stays (6.53%) with an intubation event. We trained a Categorical Boosting (CatBoost) model using vital signs, laboratory tests, demographic data, medications, organ dysfunction scores, and other patient characteristics to predict the need of intubation and mechanical ventilation using a 24-hour window of data within their hospital stay. We compared the CatBoost model to an extreme gradient boost, random forest, and a logistic regression model. The area under the receiving operating characteristic curve for the derivation cohort and the validation cohort was 0.88 (95% CI, 0.88-0.89) and 0.92 (95% CI, 0.91-0.92), respectively.

CONCLUSIONS

We developed and externally validated an interpretable machine learning prediction model that improves on conventional clinical criteria to predict the need for intubation in children hospitalized in a PICU using information readily available in the EMR. Implementation of our model may help clinicians optimize the timing of endotracheal intubation and better allocate respiratory and nursing staff to care for mechanically ventilated children.

Predictors of high-flow nasal cannula failure in pediatric patients with acute respiratory distress

BACKGROUND

Heated humidified high-flow nasal cannula (HFNC) has gained popularity recently and is considered a standard respiratory support tool for pediatric patients with acute respiratory distress. However, data are limited on the bedside parameters that can predict HFNC failure in pediatric patients.

PURPOSE

To evaluate the performance of SpO2/FiO2 (SF) ratio, pediatric respiratory rate-oxygenation (pROX) index, and clinical respiratory score (CRS), for predicting the HFNC outcomes.

METHODS

This prospective observational study included 1- month to 15-year-old patients with acute respiratory distress who required HFNC support. The HFNC setting, vital signs, CRS, and treatment outcomes were recorded. Data were analyzed to determine the predictors of HFNC failure.

RESULTS

Eighty-two children participated in the study, 16 of whom (19.5%) did not respond to HFNC treatment (failure group). Pneumonia was the main reason for intubation (62.5%). Predictors of HFNC failure at 12 hours were: SF index ≤166 (sensitivity, 62.5%; specificity, 87.8%; area under the curve [AUC], 0.75), pROX index <132 (sensitivity, 68.7%; specificity, 84.8%; AUC, 0.77), and CRS ≥6 (sensitivity, 87.5%; specificity, 96.9%; AUC, 0.92).

CONCLUSION

The CRS was the most accurate predictor of HFNC failure in pediatric patients. A CRS ≥ 6 at 12 hours after HFNC initiation and pROX, a newly modified parameter, are helpful indicators of HFNC failure.

ROX index and SpO2/FiO2 ratio for predicting high-flow nasal cannula failure in hypoxemic COVID-19 patients: A multicenter retrospective study

BACKGROUND

The ratio of oxygen saturation (ROX) index, defined as the ratio of oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) to respiratory rate, can help identify patients with hypoxemic respiratory failure at high risk for intubation following high-flow nasal cannula (HFNC) initiation; however, whether it is effective for predicting intubation in coronavirus disease 2019 (COVID-19) patients receiving HFNC remains unknown. Moreover, the SpO2/FiO2 ratio has been assessed as a prognostic marker for acute hypoxemic respiratory failure. This study aimed to determine the utility of the ROX index and the SpO2/FiO2 ratio as predictors of failure in COVID-19 patients who received HFNC.

METHODS

This multicenter study was conducted in seven university-affiliated hospitals in Korea. Data of consecutive hospitalized patients diagnosed with COVID-19 between February 10, 2020 and February 28, 2021 were retrospectively reviewed. We calculated the ROX index and the SpO2/FiO2 ratio at 1 h, 4 h, and 12 h after HFNC initiation. The primary outcome was HFNC failure defined as the need for subsequent intubation despite HFNC application. The receiver operating characteristic curve analysis was used to evaluate discrimination of prediction models for HFNC failure.

RESULTS

Of 1,565 hospitalized COVID-19 patients, 133 who received HFNC were analyzed. Among them, 63 patients (47.4%) were successfully weaned from HFNC, and 70 (52.6%) were intubated. Among patients with HFNC failure, 32 (45.7%) died. The SpO2/FiO2 ratio at 1 h after HFNC initiation was an important predictor of HFNC failure (AUC 0.762 [0.679-0.846]). The AUCs of SpO2/FiO2 ratio at 4 h and ROX indices at 1 h and 4 h were 0.733 (0.640-0.826), 0.697 (0.597-0.798), and 0.682 (0.583-0.781), respectively. Multivariable analysis showed that the patients aged ≥70 years are 3.4 times more likely to experience HFNC failure than those aged <70 years (HR 3.367 [1.358-8.349], p = 0.009). The SpO2/FiO2 ratio (HR 0.983 [0.972-0.994], p = 0.003) at 1 h was significantly associated with HFNC failure.

CONCLUSIONS

The SpO2/FiO2 ratio following HFNC initiation was an acceptable predictor of HFNC failure. The SpO2/FiO2 ratio may be a good prognostic marker for predicting intubation in COVID-9 patients receiving HFNC.

S/F and ROX indices in predicting failure of high-flow nasal cannula in children

BACKGROUND

A high-flow nasal cannula (HFNC) is a useful respiratory support for children with respiratory distress; however, it elevates the risk of belated intubation. Recently, indices based on percutaneous oxygen saturation, a fraction of inspired oxygen, and respiratory rate (RR) have been suggested for the prediction of HFNC failure. We aimed to evaluate various indices predicting HFNC failure in children who started receiving HFNC at a tertiary center for 27 months.

METHODS

Cases of HFNC failure were classified as hypoxic respiratory failure (HRF) or non-HRF (NHRF) depending on the cause of intubation. The ratio of percutaneous oxygen saturation to the fraction of inspired oxygen (S/F), the ratio of S/F to RR (ROX), the ratio of S/F to RR/median RR (ROX-M), and the ratio of S/F to z-score of RR (ROX-Z) were calculated and compared between groups.

RESULTS

Of the 152 cases, 45 (29.6%) failed to wean from the HFNC support, of which 21 (46.7%) were HRFs and 24 (53.3%) were NHRFs. The S/F and ROX-M at 6 h and 3 h, respectively, predicted HRF well with a high area under the curve. Initial hypercapnia and low weight were good predictors for NHRF.

CONCLUSIONS

For the management of children with HFNC, these risk factors and indicators should be monitored to make an early decision regarding intubation.