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.

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/μL) were compared after propensity score matching.

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/μL) 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/μL. 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.

Conclusions

Our findings suggest that lymphopenia during the first 3 weeks may be a marker of poor weaning outcomes in patients with prolonged MV.