Table 3

Nerve conduction studies in intensive care unit-acquired weakness

ConditionSensory nerve action potentialCompound muscle action potentialRepetitive stimulationNerve stimulation/direct muscle stimulation ratioElectromyography
Critical illness polyneuropathyReducedReduced amplitudeNormal<0.5Fibrillation and positive sharp waves.
Recruitment—neurogenic motor units
Critical illness myopathyNormalReduced amplitude and prolonged durationNormal>0.5Fibrillation and positive sharp waves. Short duration small amplitude motor units with early full recruitment
Prolonged neuromuscular blockadeNormalNormalDecremental responseNormalNo spontaneous activity