Cytokine plasma levels during weaning in critically ill patients with sepsis

Introduction

Poor muscle functions play a pivotal role in developing ventilator dependency after long term ventilatory support and studies have shown that sepsis may be associated with decreased muscle contractility. The aim of the study was to evaluate plasma levels of TNF alpha, IL-8 and sIL-2R during ventilatory support and weaning.

Methods

After institutional approval 40 critically ill patients were prospectively studied during ventilatory support and weaning, three patients due to death were excluded. All patients were weaned according to standard weaning protocol. Blood samples were drawn daily and collected until analysis. Apache II score, organ failure score (Goris), sepis organ failure assessment score (SOFA), ventilatory days and `weaning' days were recorded. After successful weaning patients were divided in two groups according to the length of weaning (W): group S (W ≤ 3 days, n = 15), group L (W >3 days, n = 22). TNFα, IL-8 and sIL-2R serum levels were selected and measured at the time of admission (T1), on the last day of full ventilatory support (T2), on the day when weaning was started (T3) and on the first day of spontaneous ventilation (T4). Values are expressed as a mean ± SD (or median and 25^th and 75^th percentiles), t-test or Mann Whitney Rank Sum test were used for statistical analysis (SigmaStat, Jandel Co., USA), P < 0.05 was considered statistically significant.

Results

Total ventilatory and weaning days were 9.6 ± 4.8 resp. 1.7 ± 0.7 in group S and 24.6 ± 11.3 resp. 9.0 ± 3.7 in group L. Selected results (TNFα and IL-8 in pg/ml) are presented in the Table:

Discussion

Serum TNFα and IL-8 levels were significantly higher and persisting in patients with prolonged ventilatory support. This suggests that these mediators may also be involved in ventilatory failure leading to difficult weaning after long term mechanical ventilation.

Table