Triaging acute chest syndrome clinical decision-making using bedside SaO2/FiO2 ratio

Area of Science:

• Pulmonary Medicine
• Hematology
• Critical Care Medicine

Background:

• Acute chest syndrome (ACS) in sickle cell disease (SCD) lacks consistent severity definitions and predictive tools.
• Predicting the need for intensive care unit (ICU) transfer in ACS patients is challenging.
• Current methods for assessing ACS severity and predicting clinical course are insufficient.

Purpose of the Study:

• To evaluate the utility of the oxygen saturation index (SaO2/FiO2 ratio) in predicting ICU transfer for adult ACS patients.
• To identify a reliable bedside triage tool for ACS patients requiring a higher level of care.
• To establish a specific SaO2/FiO2 ratio cutoff for early identification of ACS patients needing ICU admission.

Main Methods:

• Retrospective observational study of 227 adult ACS hospitalizations from 2017-2021.
• Analysis of the SaO2/FiO2 ratio at emergency department (ED) presentation, ACS diagnosis, and antibiotic initiation.
• Statistical modeling to assess the association between SaO2/FiO2 ratio and ICU transfer, adjusting for covariates like obesity and lung disease.

Main Results:

• The SaO2/FiO2 ratio at ACS diagnosis (AUC, 0.73) and antibiotic initiation (AUC, 0.74) strongly predicted ICU transfer.
• A diagnostic SaO2/FiO2 cutoff of 310 demonstrated high sensitivity (63%) and specificity (82%) for predicting ICU transfer.
• This cutoff correlates with pulse oximetry saturation <90% on 2 L/min nasal cannula support.

Conclusions:

• The SaO2/FiO2 ratio is a valuable tool for predicting ICU transfer in adult ACS patients.
• A proposed SaO2/FiO2 ratio cutoff of 310 at ACS diagnosis can serve as a simple bedside triage tool.
• Prospective validation of this cutoff is recommended for optimizing patient management and resource allocation in ACS care.