Title: ROX Index for Predicting Outcomes of HFNC<br/>Author: Caleb Chan<br/><a href='http://umem.org/profiles/resident/1583/'>[Click to email author]</a><hr/><p>
<u>Design</u><br />
-Two-center prospective observational study with 157 patients admitted to the ICU for pneumonia and being treated with HFNC<br />
-<strong>ROX (Respiratory rate-OXygenation) index = ratio of SpO2/FIO2 to RR</strong></p>
<p>
<u>Results:</u><br />
-ROX index ≥4.88 at 12 hours after HFNC onset with a sensitivity of 70.1%, a specificity of 72.4%, PPV of 89.4%, NPV of 42%, LR+ of 2.54, and LR- of 0.41 in predicting treatment failure</p>
<p>
Validation study: Roca, 2019<br />
-results similar, but ROX index ≥4.88 at 12 hour with LR+ of only 1.82<br />
-also found that a ROX index of <3.85 at 12 hours had a sensitivity of 23.5%, specificity of 98.4%, PPV of 88.9, NPV 69.9, LR+ of 14.47, and LR- 0.78</p>
<p>
<u>Pitfalls:</u><br />
-decision to intubate was not made based on ROX index<br />
-criteria for intubation was also part of the ROX index<br />
-NIV was not part of their treatment algorithm<br />
-created and validated prior to current COVID-19 pandemic</p>
<p>
<u>Takeaways:</u><br />
- The ROX index can be a tool to help predict whether a patient with pneumonia on HFNC may need mechanical ventilation or higher level of care<br />
- May be most helpful with patients with pneumonia on HFNC boarding in the ED<br />
- At 12 hours of HFNC, ROX index of >4.88 suggests patient likely to succeed with HFNC vs. <3.85 which suggests likely need for mechanical ventilation</p>
<fieldset><legend>References</legend>
<p>
Roca O, Messika J, Caralt B, et al. Predicting success of high-flow nasal cannula in pneumonia patients with hypoxemic respiratory failure: The utility of the ROX index. J Crit Care. 2016;35:200-5.</p>
<p>
Roca O, Caralt B, Messika J, et al. An Index Combining Respiratory Rate and Oxygenation to Predict Outcome of Nasal High-Flow Therapy. Am J Respir Crit Care Med. 2019;199(11):1368-1376.</p>
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