Metabolic aspects of critical illness polyneuromyopathy

Critically ill patients frequently develop muscle weakness due to critical illness-related acute neuropathy and/or myopathy. This is a frequent disorder, with important short-term consequences that include difficulties in weaning from mechanical ventilation, associated prolonged intensive care unit and hospital stay, and increased mortality rates. In addition, many patients continue to suffer from decreased exercise capacity and quality of life for months to years after the acute event. Many different mechanisms seem to be involved in the development of this process. In this review, we will focus on the metabolic aspects of critical illness-related acute neuropathy and/or myopathy and, more specifically, on our clinical experience with achieving strict glycemic control using insulin. Our group has performed two randomized controlled trials in surgical and medical critically ill patients and studied the occurrence of critical illness-related acute neuropathy and/or myopathy and delayed weaning, one of its most important complications. Potential underlying mechanisms derived from experimental studies and from the analysis of biopsy samples harvested from critically ill patients or patients suffering from other catabolic states are discussed.