Postoperative neuromuscular function following non-depolarising muscle blockade in patients at Inkosi Albert Luthuli Central Hospital, Durban

Abstract

Background: Residual neuro-muscular blockade after the end of general anaesthesia may occur when non-depolarising muscle relaxant (NDMR) drugs are used. Train-of-four (TOF) stimulation is used to quantify the degree of residual paralysis, with a TOF ratio of less than 0.9 postoperatively associated with increased morbidity in patients. The aim of this study was to survey the degree of residual paralysis in patients in the post-anaesthesia care unit (PACU) at Inkosi Albert Luthuli Central Hospital (IALCH), Durban, over the survey period.

Methods: This cross-sectional observational study was performed over a two-month period at IALCH, assessing the postoperative neuromuscular function of patients who had received NDMR drugs (rocuronium (n = 64) or cisatracurium (n = 6)) intraoperatively. Muscle function was assessed using acceleromyography and TOF stimulation, utilising a TOF Watch SX device, with function grouped according to previously defined targets as less than a ratio of 0.7, less than a ratio of 0.9 and less than a ratio of 1.0.

Results: Recovery to a TOF ratio of less than 0.7, 0.9 or 1.0 was observed in 5 (7.1%), 20 (28.6%) and 44 (62.9%) of patients respectively.

Conclusions: Although the results obtained compare favourably with other studies in similar patient populations, a considerable subset of patients still arrive in the PACU with inadequate return of neuromuscular function.

Keywords: post-anaesthesia, postoperative residual curarisation, postoperative residual weakness, residual block, residual neuromuscular block, residual paralysis