Incidence and determinants of post-operative neuromuscular blockade in patients undergoing surgery at the university teaching hospital, Lusaka, Zambia.

Background: Anaesthesia provision has advanced significantly over the years. This is in part due to the development of newer, better drugs. Some of these drugs include the muscle relaxants, which paralyze the body. However, drugs, particularly muscle relaxants, are not without fault. Various Western studies have highlighted some adverse effects of some of these drugs, such as post-operative muscle paralysis, leading to infections and death. Despite the routine use of these drugs at the University Teaching Hospital, there is lack of information regarding their potential for post-operative paralysis in the surgical population at this hospital.
Methods: a prospective cross-sectional study was conducted between September 2019 and January 2020 involving adult patients who presented for surgery (elective or emergency) at the University Teaching Hospital theatres. Data was collected from 38 participants regarding their demographics, anaesthetic factors including the type of drug, and surgical factors such as duration of operation. A Train of Four Scanner which measures the level of muscle function was used to determine post-operative paralysis in the participants. The datasets obtained were compared using Mann-Whitney tests, and a multivariable regression model was used to analyse determinants of non-recovery.
Results: post-operative neuromuscular blockade was determined to be present in 13 (34.2%) participants presenting for surgery under general anaesthesia. The risk of residual block increased with increasing age (AOR = 1.2, 95% CI [1.09 – 1.37]; p=0.044), use of pancuronium alone (AOR=2.3; 95% CI [1.21 – 14.9]; p=0.038) or in combination with atracurium (AOR=3.2; 95% CI [1.73-8.41]; p=0.029) and administering reversal agent (AOR = 1.9, 95% CI [1.33 – 5.21]; p=0.048).

Conclusion: Post-operative neuromuscular blockade had an incidence of 34.2% in the study population. It was significantly associated with use of pancuronium, even despite subsequent reversal. In fact, use of neostigmine for reversal was associated with inadequate muscle recovery as determined by the train of four ratio.