Cheong 1999.

Methods	Prospective, randomized clinical trial
Participants	N = 63, adult patients scheduled for orthopaedic surgery of lower extremity under general anaesthesia. Patients with anticipated airway difficulty, history of gastro‐oesophageal reflux, hiatal hernia, previous gastric surgery or morbid obesity, and those who were receiving medications affecting gastric pH (H2 blockers) were excluded from the study
Interventions	Type of LMA: LMA Classic Early removal ‐ The LMA was removed when signs of rejection like swallowing, struggling and restlessness appeared Late removal ‐ The LMA was removed when the patient could open his or her mouth on command
Outcomes	Coughing Desaturation <95% Bucking and straining Pulmonary aspiration
Notes	Induction ‐ thiopental + succinylcholine Maintenance ‐ N2O + O2 + enflurane+ vecuronium
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"At the end of the operation (to avoid the anaesthesiologists' bias during the period of anaesthetic induction and maintenance), patients were allocated randomly by coin toss to one of the two groups"
Allocation concealment (selection bias)	Unclear risk	COMMENT ‐ It is not clear if the anaesthesiologist observing the outcomes was aware or unaware of the allocation
Blinding (performance bias and detection bias) Of outcome assessor to all outcomes	Low risk	"Physical events during the arousal phase ‐ bucking, straining and coughing ‐ were recorded by an independent observer"
Incomplete outcome data (attrition bias) All outcomes	Low risk	"The situations to consider eliminating the subject from data analysis did not arise"
Selective reporting (reporting bias)	Low risk	COMMENT ‐ Though no explicit statement, the outcomes mentioned in methodology have been reported for all patients