The prognostic value of nutritional and inflammatory indices in critically ill patients with acute respiratory failure.

In critically ill patients suffering from acute respiratory failure, weaning from ventilatory assistance is a key survival factor in intensive care units (ICU). The aim of this study was to provide deeper insight into laboratory methods allowing improved monitoring of that critical period. Eighty-three ICU patients (mean age 63.9 years), classified according to the Second Acute Physiology and Chronic Health Evaluation criteria, were submitted to mechanical ventilation, antibiotherapy and nutritional support. Weaning attempts required degressive pressure support ventilation. The biological status of the patients was assessed by the serial measurement of inflammatory (C-reactive protein and alpha1-acid glycoprotein) and of nutritional (albumin and transthyretin) indicators whose aggregation yields a prognostic inflammatory and nutritional index (PINI). Statistical analyses compared ventilatory and biological data recorded on admission and at the time of extubation. Results showed that vital capacity and plasma concentrations of albumin and transthyretin rose, whereas rapid shallow breathing index, C-reactive protein and PINI values declined during the tested period. Persistent low transthyretin concentrations were predictive of lethality while increased values were associated with improved ventilatory performances. The PINI scoring formula worked as an independent predictor of the weaning trial outcome. The study underlined the value of the PINI system for the successful management of the weaning procedure.