Lymphopenia in patients submitted to assisted ventilation due to aggravated chronic respiratory failure: a prospective study

Evaluate and characterize lymphopenia in patients admitted to the Intensive Care Unit (ICU) for mechanical ventilation due to aggravated chronic respiratory failure and its probable relation to severity. Prospective study over a period of 6 months with another 6 months follow-up after ICU discharge. The study included 24 patients, 22 males, with mean APACHE II of 19,7, three of whom with capacity for outpatient follow-up. Lymphocyte subpopulations were determined on admission and every 7 days after mechanical ventilation. Patients with evidence of infection or previous immunossupression, with the exception of steroids, were excluded from the study. Lymphopenia was found in 79,2% of patients with depletion of all lymphocyte series, although with greater expression for B lymphocytes CD19+. This depletion showed no relation with serum steroid levels, and although related to greater clinical severity, no correlation was found with mortality. Lymphocyte values recovered progressively during admission. Lymphopenia is frequent among ventilated patients with chronic respiratory exacerbation. It's a non-selective depletion, more evident with CD19+ B lymphocytes. These patients present higher severity scores but no difference in mortality. Outpatient follow-up was difficult and inconclusive.