Red Cell Distribution Width (RDW) as a New Modality in Diagnosis and Prognosis of Ventilator-Associated Pneumonia (VAP)

Abstract

Background: Ventilator-associated pneumonia (VAP) is a prevalent nosocomial infection in intensive care units (ICUs), with a high death rate, a prolonged stay in the ICU, and an increased health care expense. The goal of this study was to assess the diagnostic and prognostic value of RDW in VAP.

Methods: This prospective cohort observational study was established on  on 106 critically ill mechanically ventilated patients who referred to ICU. They were classified into two groups: VAP (31 patients) and non VAP (75 patients) group. clinical pulmonary infection score(CPIS), sputum culture results, ICU stay period, incidence of 28^th day morality, acute physiology and chronic health evaluation (APACHE) II score, antibiotics and laboratory test including ( PCT: at day of admission, within 7 days after admission in suspected VAP cases, RDW: was analysed daily from admission until VAP diagnosis within 7 days from the day of admission and CRP: was analysed daily from admission until VAP diagnosis within 7 days from the day of entrance(

Results: There was a positive significant correlation between RDW at time of diagnosis and CPIS (r = 0.247, P =0.04) and between RDW at time of diagnosis and APACHE (r = 0.476, P <0.001). RDW at time of diagnosis and Delta RDW was significantly higher in non-survivors group than survivors group (P = 0.020, p=0.021 respectively). RDW was at cut-off >16.3 significantly predict mortality with sensitivity of 84.62, specificity was 52.69, PPV was 20, NPV was 96.1, AUC was 0.806 and P value was <0.001 There was a positive significant correlation between RDW and delta RDW at time of diagnosis and duration of MV (r = 0.317, r = 0.398 respectively and P <0.001) and between delta RDW and ICU stay (r = 0.279, P = 0.004).

Conclusions: RDW at time of diagnosis and delta RDW are good diagnostic and prognostic markers of (VAP) and better than CRP and procalcitonin. RDW is correlated to duration of mechanical ventilation, CPIS, APACHE and 28^th day mortality.