Splinter 1997.

Methods	Prospective, randomized, single‐blind study
Participants	N = 333, ASA I‐II, age 1.5 to 15 years
Interventions	Early removal ‐ The LMA was removed before return of airway reflexes. Late removal ‐ The LMA was removed after patient had awakened and had intact airway reflexes, exhibiting purposeful movements including swallowing as an indication of protective reflexes
Outcomes	Laryngospasm Desaturation (< 90%) Postop nausea or vomiting Stridor Breath holding Excessive salivation
Notes	Induction ‐ N2O + O2+ halothane/propofol Maintenance ‐ N2O + halothane, isoflurane in older children
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomly assigned via a computer generated random numbers table"
Allocation concealment (selection bias)	Unclear risk	COMMENT ‐ No mention of method of allocation concealment
Blinding (performance bias and detection bias) Of outcome assessor to all outcomes	Unclear risk	"single blinding" COMMENT ‐ It is not clear if the outcome assessor was blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	COMMENT ‐ 333 patients were enrolled but 25 did not undergo intervention (the LMA was not used in 17 and surgery was cancelled in 8). However, the results are reported in 310 patients (no response to correspondence seeking clarification on this discrepancy)
Selective reporting (reporting bias)	Low risk	COMMENT ‐ Though no explicit statement, the outcomes mentioned in methodology have been reported