Association Between Peripheral Blood Oxygen Saturation (SpO2)/Fraction of Inspired Oxygen (FiO2) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients

Jason Y. Adams, Angela J. Rogers, Alejandro Schuler, Gregory P. Marelich, Jennifer M. Fresco, Sandra L. Taylor, Albert W. Riedl, Jennifer M. Baker, Gabriel J. Escobar, Vincent X. Liu

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


INTRODUCTION: Acute respiratory failure requiring mechanical ventilation is a leading cause of mortality in the intensive care unit. Although single peripheral blood oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) ratios of hypoxemia have been evaluated to risk-stratify patients with acute respiratory distress syndrome, the utility of longitudinal SpO2/FiO2 ratios is unknown. OBJECTIVE: To assess time-based SpO2/FiO2 ratios ≤ 150-SpO2/FiO2 time at risk (SF-TAR)-for predicting mortality in mechanically ventilated patients. METHODS: Retrospective, observational cohort study of mechanically ventilated patients at 21 community and 2 academic hospitals. Association between the SF-TAR in the first 24 hours of ventilation and mortality was examined using multivariable logistic regression and compared with the worst recorded isolated partial pressure of arterial oxygen/fraction of inspired oxygen (P/F) ratio. RESULTS: In 28,758 derivation cohort admissions, every 10% increase in SF-TAR was associated with a 24% increase in adjusted odds of hospital mortality (adjusted odds ratio = 1.24; 95% confidence interval [CI] = 1.23-1.26); a similar association was observed in validation cohorts. Discrimination for mortality modestly improved with SF-TAR (area under the receiver operating characteristic curve [AUROC] = 0.81; 95% CI = 0.81-0.82) vs the worst P/F ratio (AUROC = 0.78; 95% CI = 0.78-0.79) and worst SpO2/FiO2 ratio (AUROC = 0.79; 95% CI = 0.79-0.80). The SF-TAR in the first 6 hours offered comparable discrimination for hospital mortality (AUROC = 0.80; 95% CI = 0.79-0.80) to the 24-hour SF-TAR. CONCLUSION: The SF-TAR can identify ventilated patients at increased risk of death, offering modest improvements compared with single SpO2/FiO2 and P/F ratios. This longitudinal, noninvasive, and broadly generalizable tool may have particular utility for early phenotyping and risk stratification using electronic health record data in ventilated patients.

Original languageEnglish (US)
JournalThe Permanente journal
StatePublished - Jan 1 2020

ASJC Scopus subject areas

  • Medicine(all)


Dive into the research topics of 'Association Between Peripheral Blood Oxygen Saturation (SpO<sub>2</sub>)/Fraction of Inspired Oxygen (FiO<sub>2</sub>) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients'. Together they form a unique fingerprint.

Cite this