The prognosis of critically ill patients is significantly influenced by the development of acquired affections of the neuromuscular system which leads to generalized muscular weakness and difficulties when switching over from mechanical to spontaneous ventilation. Recently in these patients two assumed nosological units were described: – critical illness polyneuropathy – CIP; – acute quadriplegic myopathy – AQM. The authors made a prospective clinical and electrophysiological pilot study in seven critically ill patients with the objective to assess the prevalence of acquired generalized muscular weakness and the possibility to differentiate between the mentioned units: CIP and AQM. Signs of the affection of the peripheral neuromuscular system were found in four patients. It was not possible to differentiate reliably, clinically nor by standard electromyographic techniques, between affections of the type of neuropathy and myopathy except by the method of so-called direct muscle stimulation. The findings revealed that in the majority a concurrent affection of both systems is involved – polyneuro- myopathy – and differentiation of two independent units (CIP and AQM) is not substantiated.

        Key words: critical illness polyneuropathy, acute quadriplegic myopathy, critical illness polyneuro-