Selected biochemical values and organ dysfunction assessment in prediction of difficult to wean patients

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Introduction

Metabolic status and severity of illness play an important role in developing ventilatory dependency during long term ventilatory support in critically ill patients. The aim of the study was to evaluate selected clinical and biochemical values in order to identify `difficult to wean' and `easy to wean' patients during ventilatory support.

Methods

After institutional approval, 40 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, organ failure score (Goris), sepis organ failure assessment score (SOFA), ventilatory days, and `weaning' days were recorded. After successful weaning, patients were divided into two groups according to the length of weaning (W): group S (W ≤ 3 days, n=15), group L (W > 3 days, n=22). Serum levels of albumin, prealbumin, cholinesterase, CRP, magnesium, phosphorus and urine levels of myoglobin were measured during ventilatory support (including weaning trials). SigmaStat Statistical Software was used for analysis, r=corr. coeff., ^*P<0.05.

Results

There were no significant differences in any biochemical values between groups during ventilatory support. In group L there were positive significant correlations between SOFA score and length of ventilatory support and weaning (r=0.473, P=0.035) and between Goris score and length of ventilatory support (r=0.626, P=0.003).

Conclusion

Assesment of severity of organ dysfunction, but no special biochemical values, seems to be from `cost/effectiveness point-of-view' the best way to identify patients with need for long term ventilatory support and who are difficult to wean.