Nunez 1998.

Methods	Prospective, randomized, single‐centre trial
Participants	N = 66, ASA I‐II, scheduled for elective urological, orthopaedic and minor breast surgery Exclusion criteria ‐ age < 18 and > 80 years Pathology of neck, upper respiratory or upper alimentary tract pathology, those at risk of pulmonary aspiration of gastric contents
Interventions	Early removal ‐ The LMA was removed while the patient was still deeply anaesthetized at the end of the operation, immediately after discontinuing the volatile agent and nitrous oxide Late removal ‐ The LMA was removed once the patient regained consciousness spontaneously and was able to respond to the verbal command to open the mouth
Outcomes	Laryngospasm Coughing Desaturation Airway obstruction
Notes	Induction ‐ propofol 2.5 to 3.0 mg/kg + alfentanil 10 to 20 mcg/kg Maintenance ‐ isoflurane 1% to 2% in nitrous oxide and O2 on spontaneous respiration LMA size 4 for females and size 5 for males
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Allocated randomly to one of two groups by blocked randomization (in blocks of 10)"
Allocation concealment (selection bias)	Unclear risk	COMMENT ‐ No information on the method of allocation concealment
Blinding (performance bias and detection bias) Of outcome assessor to all outcomes	High risk	Not done
Incomplete outcome data (attrition bias) All outcomes	Low risk	COMMENT ‐ Outcomes reported for all 66 patients randomized
Selective reporting (reporting bias)	Low risk	COMMENT ‐ Though no explicit statement, the outcomes mentioned in methodology have been reported