Serum TNF alpha and IL-8 levels in difficult weaning patients

Introduction

Metabolic status and severity of illness play important role in developing ventilatory dependency during long term ventilatory support in critically ill patients. The aim of the study was to evaluate TNFα and IL-8 serum levels during weaning from long term ventilatory support.

Methods

After institutional approval 26 critically ill patients were prospectively studied during ventilatory support and weaning. All patients were weaned according to standard weaning protocol. Blood samples were drawn daily and collected until analysis. Apache II score, 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 = 6), group L (W ≤ 3 days, n = 20). TNFα and IL-8 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 after 24 h of spontaneous ventilation (T4). Values are expressed as a mean ± SD, t-test or Mann Whitney Rank Sum test where appropriate were used for statistical analysis (Sigma Stat Statistical Software, Jandel Co., USA), P < 0.05 was considered statistically significant.

Results

Total ventilatory and weaning days were 24.1 ± 11, resp. 7.5 ± 3 in group L and 10.7 ± 4.6 resp. 2.6 ± 1.7 in group S. Selected results of TNFα (in pg/ml) and IL-8 (in pg/ml) are presented in the table.

Discussion

Serum TNFα and IL-8 levels were persistent 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 1 Table (abstract P030)