Positive fluid balance and subsequent oedema are typical sequelae of critical illness. Although the pathogenesis of oedema formation is well known, the detailed clinical consequences of the oedema remain to be elucidated. The aim of this study is to describe the relationship between the characteristics of the positive fluid balance and the neuromuscular abnormalities tkat occur during critical illness. Methods: In 14 critically ill patients with polyneuromyopathy, parameters of fluid balance were followed up (i. e. the velocity of fluid retention, maximal amount of accumulated fluid, the velocity of oedema mobilisation and the respective time characteristics). Electrophysiological studies of peripheral nerves and muscles and muscle biopsies were performed. Fluid balance characteristics were correlated with the neuromuscular parameters and with other clinical data. Results: No correlation was found between neuromuscular data and fluid balance parameters. Significant correlation between the parameters of neuromuscular damage and the symptoms of vítal organ dysfunction was found. The reduction of the compoud muscle action potentials correlated signiflcantly with the Bose of neuromuscular blocking agent pipecuronium (r=-0.79, p<0.0001). Conclusions: No correlation between fluid balance and neuromuscular parameters was found. The correlation between neuromuscular abnormalities and vítal organ dysfunction suggests tkat neuromuscular failure can be regarded as a part of multiple organ failure syndrome. Neuromuscular condition in the critically ill can be significantly deteriorated when neuromuscular blocking agents are used.

        Key words: fluid balance, critical illness, critical illness polyneuropathy, critical illness myopathy, multiple organ failure.