Comparison of SpO2/FiO2 and PaO2/FiO2 ratios as markers of acute lung injury

Abstract

Background One of the diagnostic criteria for acute lung injury (ALI) is the PaO2/FiO2 (P/F) ratio. This measurement is obtained by blood gas analysis, which involves an invasive procedure (arterial blood draw). In order to reduce invasive procedures on critically ill patients, an alternative non-invasive marker for ALI is needed. The SpO2/FiO2 (S/F) ratio attained by pulse oximetry may be a suitable alternative.Objective To investigate for a correlation between S/F ratio and P/F ratio, in order to find an alternative non-invasive marker of ALI.Methods A cross-sectional study was conducted in the pediatric intensive care unit (PICU) at Haji Adam Malik Hospital, Medan from August 2012 to June 2013. Subjects (children aged 1 month – 18 years) underwent blood gas analysis when their pulse oximetry showed saturation of 80-97% within 24 hours of ventilator use. We measured PaO2, SpO2, and FiO2 and calculated S/F and P/F ratios. Data were analyzed by Spearman’s correlation and linear regression tests.Results Of 69 PICU patients, 39 children fulfilled the criteria for ALI. The S/F ratio and P/F ratio had a weak correlation (r=0.2; P=0.18). The linear regression equation was S/F ratio = 129.67 + 0.11 (P/F), with S/F ratio values of 162.67 and 151.67 correlating to P/F ratio values of 300 and 200, respectively.Conclusion The S/F ratio has a weak correlation with P/F ratio for ALI in children.

Correlation Between the Ratio of Oxygen Saturation to Fraction of Inspired Oxygen and the Ratio of Partial Pressure of Oxygen to Fraction of Inspired Oxygen in Detection and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome

“…In the present study, we found a strong correlation between SF and PF ratios (r=0.688; p=0.001) among 120 children with ARDS. In a similar study by Laila et al, a positive but weak correlation was observed between SF and PF among 39 patients with pARDS (r=0.215, p=0.189) [ 21 ]. In another similar study by Khemani et al, a moderate correlation was found between SF and PF (r=0.47) among 383 children with ARDS [ 10 ].…”

“…Without the use of blood gas analysis, SpO 2 measurement with pulse oximetry might be a better technique for predicting PaO 2 value. However, factors such as the placement of the oximetry sensor, race, methemoglobin, and underlying condition might reduce the diagnostic accuracy of the SpO 2 measurement [ 21 ]. In the current study, we found the mean values of SpO 2 and PaO 2 as 94.4% and 100.35 mmHg, respectively.…”

Comparison of non-invasive to invasive oxygenation ratios for diagnosing acute respiratory distress syndrome following coronary artery bypass graft surgery: a prospective derivation-validation cohort study

“…A study by of 1742 matched measurements of S p O 2 and P a O 2 in adult patients undergoing general anesthesia sought to identify a correlation between the S/F and P/F ratios by incorporating the S/F into the respiratory component of the SOFA score and found that both predicted similar outcomes [ 26 ]. Results were less convincing in the pediatric population, where only a weak correlation between S/F and P/F was noted in children with acute lung injury (age 1 month to 18 years) [ 27 ]. In an analysis of patients from the ARDS Network, S/F ratios of 235 and 315 correlated with PF ratios of 200 and 300 respectively [ 20 ].…”

Evaluation of the PaO2/FiO2 Ratio as a Risk Factor for Hypoxemia against Septicemia Mortality in Children who Treated at Dr. Soetomo General Hospital

“…The cut-off of S/F ratio <300 indicates high specificity of mortality prognosis. 23 Data on the first-day in septicemia patients who are non-survivor showed a low P/F ratio. Meanwhile, survivor septicemia patients showed a higher P/F ratio, but we still need further study, because the patient's condition is certainly supported by many factors.…”