Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 9 Supp. 2 2023 09 23 474 478 Shervin Ramezani Department of Anesthesiology, Tehran University of Medical Sciences, Tehran, Iran. Hesam Aldin Varpaei College of Nursing, Michigan State University, East Lansing, USA. Mostafa Mohammadi Department of Critical Care, Tehran University of Medical Sciences, Tehran, Iran. Hamid Rahmani Department of Pharmacology, Tehran University of Medical Sciences, Tehran, Iran. Masoud Ramezani Department of Critical Care, Tehran University of Medical Sciences, Tehran, Iran. 2022 11 15 2023 01 09 Background: Ventilator-associated pneumonia (VAP) is a consequence of mechanical ventilation, which can be fatal. Several markers are available to predict outcomes related to VAP. Choosing a predictor that is inexpensive, affordable, and accurate is advantageous. This study aimed to examine red cell distribution width (RDW) as a predictor of mortality in patients with VAP. Methods: This prospective cohort study was conducted among 49 patients in the intensive care unit (ICU) of Valiasr Hospital in Tehran. A researcher-made checklist was used to collect RDW and other marker data, as well as mortality outcomes and length of stay (LOS) in the ICU. The Pearson correlation coefficient in the SPSS software and the regression model in the Eviews software were used to examine the relationship between markers and different outcomes. Results: Of a total of 49 patients (57.1% male; mean age = 54 ± 16), the length of ICU stays ranged from 7 to 14 days. According to the Pearson correlation coefficient, a significant association between RDW and mortality (P =.009) was noted. But no significant relationship between RDW and length of stay in the ICU (P =.81) was noted. Additionally, the regression model showed a positive relationship between RDW and white blood cells (WBC), lactate, and sequential organ failure assessment (SOFA). Conclusion: Our study showed a positive but weak correlation between RDW and ICU mortality in patients with VAP. Due to its availability and low cost of measurement, RDW is an appropriate option for predicting mortality risk in patients who are admitted to the ICU and develop VAP. https://aacc.tums.ac.ir/index.php/aacc/article/view/671