• Respirology · Jul 2015

    Multicenter Study Observational Study

    Accuracy of PaO2 /FiO2 calculated from SpO2 for severity assessment in ED patients with pneumonia.

    • Francisco Sanz, Nathan Dean, Justin Dickerson, Barbara Jones, Daniel Knox, Estrella Fernández-Fabrellas, Eusebi Chiner, María Luisa Briones, Ángela Cervera, María Carmen Aguar, and José Blanquer.
    • Pulmonology Department, Consorci Hospital General Universitari de València, València, Spain.
    • Respirology. 2015 Jul 1; 20 (5): 813-8.

    Background And ObjectiveAssessment of oxygenation in patients with community-acquired pneumonia is critical for treatment. The accuracy of percutaneous oxygen saturation (SpO2 ) determined by pulse oximetry is uncertain, and it has limited value in patients receiving supplemental oxygen. We hypothesized that calculation of partial arterial oxygen concentration/inspired oxygen faction (PaO2 /FiO2 ) from SpO2 by the Ellis or Rice equations might adequately correlate with PaO2 /FiO2 measured by arterial blood gases.MethodsWe studied 1004 patients with pneumonia in the emergency department with simultaneous measurement of SpO2 and PaO2 from two cohorts from Valencia, Spain and Utah, USA. We compared SpO2 with measured SaO2 , compared the equations' accuracy in calculating PaO2 /FiO2 and determined how often patients would be misclassified at clinically important thresholds. We compared estimated PaO2 /FiO2 to measured PaO2 /FiO2 using the Spearman correlation.ResultsPairwise correlation of SpO2 with SaO2 was moderate (rho = 0.66; P < 0.01). Both equations performed similarly among patients with lower PaO2 /FiO2 ratios. The Ellis equation estimated PaO2 /FiO2 from SpO2 more accurately than the Rice equation in patients with PaO2 /FiO2 ≥200. Simple agreement between calculated and measured P/F was 91% and 92%, respectively.ConclusionsThe Ellis equation was more accurate than the Rice equation for estimating PaO2 /FiO2 , especially at higher levels of P/F ratio. Estimation of PaO2 /FiO2 from SpO2 is accurate enough for initial oxygenation assessment. Ellis and Rice equations could misclassify 20% and 30% of patients, respectively, at higher levels of PaO2 /FiO2 . For patients with abnormal oxygenation falling near thresholds for clinical decision making, arterial blood gas measurement preferably on room air is more accurate.© 2015 Asian Pacific Society of Respirology.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…