Persistent inflammation and lymphopenia and weaning outcomes of patients with prolonged mechanical ventilation

Background: Weaning outcomes of patients receiving mechanical ventilation (MV) are affected by multiple factors. A clinical feature of critically ill patients is the presence of lymphopenia, however the clinical significance of lymphopenia in patients receiving prolonged MV remains unclear.<br /> Methods: We enrolled patients who received at least 21 consecutive days of MV in a medical center in Taiwan between 2007 and 2016. Patients with and without lymphopenia (mean count <1000/mu L) were compared after propensity score matching.<br /> Results: Of the 3460 patients included in the analysis, 1625 (47.0%) were liberated from MV within 100 days. Lymphopenia and severe lymphopenia (mean count <500/mu L) during the first 21 days of MV were common (52.9% and 14.5%, respectively), and restricted cubic spline analysis showed a significant reduction in weaning success when the lymphocyte count dropped below 1000/mu L. After propensity score matching, the patients with lymphopenia during the third week had a lower rate of weaning success within 100 days (p = 0.005) and a higher in-hospital mortality rate (p = 0.001) than those without lymphopenia. The lymphopenia group also had significantly reduced platelet (p < 0.001) and albumin (p < 0.001) levels.<br /> Conclusions: Our findings suggest that lymphopenia during the first 3 weeks may be a marker of poor weaning outcomes in patients with prolonged MV.