Incidence, associated factors and complications of residual neuromuscular blockade among adult patients in the post anaesthesia care unit: a multicenter prospective observation study.

Abstract

Residual neuromuscular blockade (RNMB) is a major deterrent to use of Neuromuscular blocking drugs (NMBDs) during general anaesthesia. It is associated with potentially fatal Acute Respiratory Events (AREs) like upper airway obstruction, aspiration, hypoxia and atelectasis. In this study, we set out to determine the incidence, associated factors and complications of RNMB in our setting. Methodology: We conducted a multicenter prospective observational study in three Ugandan referral hospitals. We recruited 485 adult patients (≥18 years) admitted to the Post Anaesthesia Care Unit (PACU) who had received a Non-Depolarizing Neuromuscular Blocking Drug (ND-NMBD) during surgery. The primary outcome was the incidence of RNMB in the PACU defined as a train of four ratio (TOFR) less than 0.9 measured at the adductor pollicis using acceleromyography. Associated factors and complications of RNMB were also studied. Results: Postoperative RNMB was detected in 160 (33%) patients and AREs were noted in 177 (36.5%) patients. Elderly patients (age >65) and patients who received additional doses of NMBDs intraoperatively were more likely to have RNMB, OR 2.39 and 6.08 respectively. Use of neostigmine and surgeries lasting >90 minutes were protective against RNMB, OR 0.43 and 0.18 respectively. We found no correlation between RNMB and obesity or use of long acting NDNMBDs. Independent risk factors of AREs in the PACU were obesity (BMI ≥30) and level of consciousness on the Aldrete score of less than 2 at admission to PACU. Residual neuromuscular blockade was not associated with significant increase in AREs and length of stay in the PACU. Conclusion: The incidence of postoperative RNMB is high. The risk was higher in the elderly and those who received additional doses of NMBDs. There is need for routine monitoring of perioperative NeuroMuscular Blockade (NMB) and use of NMBD reversal agents.