This study aims to establish the incidence of residual paralysis in patients following administration of a mini- dose of atracurium (less than ED95 i.e. <0.23mg/kg or <15 mg in most patients) during supraglottic airway insertion and correlate it with the duration of time from drug administration to arrival at PACU. The secondary aim is to compare the incidence of residual paralysis in patients who receive full doses of atracurium (per body weight) with those who receive mini-doses.

Post-operative residual paralysis may be defined as the incomplete recovery of muscle function following intra-operative administration of neuromuscular blockers (NMBs). This condition is associated with many negative patient outcomes such as: increased risk of aspiration; upper airway obstruction; and delayed Post-Anaesthetic Care Unit (PACU) discharge, amongst others. Despite the increasing use of shorter acting agents, the prevalence of residual paralysis in the PACU remains high at 20-50%. NMBs are commonly used to facilitate endotracheal intubation and insertion of the supraglottic airway by obtunding airway reflexes. Given the increasing use of mini-dose NMBs without post-operative reversal in clinical practice, there is a need to evaluate the incidence of residual paralysis in the patient population who have received mini-dose atracurium during the supraglottic airway insertion.

Inclusion Criteria:

• Adults above 21 years old
• Received either a mini-dose of atracurium or full dose of atracurium during the placement of the supraglottic airway
• Did not receive any neuromuscular reversal agent at any point of the operation.

Exclusion Criteria:

• Patients with underlying neuromuscular disease
• Patients who received pre-operative medication that may affect neuromuscular transmission
• Patients who required additional doses of neuromuscular blockade at any point of the operation

The study population will be picked from all patients who are going surgery at National University Hospital (NUH) during the period of data collection, and who are receiving supraglottic airway for their procedure. They must fulfil the inclusion and exclusion criteria.