Quantitative assessment of residual antidepolarizing block (Part II)

Abstract

An attempt to estimate residual neuromuscular blockade after the administration of anti-depolarizing relaxants to anaesthetized patients is described. A train of four supra-maximal nerve stimuli was applied to the ulnar nerve and the twitch response (mechanical or electrical) was recorded. The frequency of the train used was 2-2.4 Hz with an interval of 10 seconds between the trains. Clinical recovery from the relaxant was assessed by the ability to lift the head. The ratio of the height of the fourth response of the train to that of the first (ratio (c)) gave a good indication of the degree of residual neuromuscular block as indicated by this simple clinical test. As ratio (c) increased muscle power improved. Obvious muscle weakness was associated with values of ratio (c) of less than 0.6. © 1971 John Sherratt & Son Ltd.