Baird 1999.
| Methods | Prospective, randomized, single‐centre trial | |
| Participants | N = 300, age 1.5 to 81 years, scheduled for elective day‐case surgery | |
| Interventions | Type of LMA: LMA Classic Early removal ‐ The LMA removed by anaesthetist in operating theatre and replaced by appropriately sized Guedel airway and oxygen delivered by Hudson mask Late removal ‐ The LMA left in situ with oxygen delivered through modified T piece ‐ removed by awake patients themselves or nurse under supervision in PACU. Patient was considered awake if he or she could open eyes and mouth |
|
| Outcomes | Coughing Desaturation defined as oxygen saturation < 96% Airway obstruction |
|
| Notes | No premedication Anaesthesia induced with propofol and fentanyl, maintained on N2O + O2 + Isoflurane Patients breathed spontaneously during the procedure |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Patients assigned to one of two groups by random allocation. Randomization was carried out by "envelope randomization in the operating theatre" COMMENT ‐ There is no description of method used for generation of random sequence such as shuffling of envelope or coin tossing |
| Allocation concealment (selection bias) | Unclear risk | "No patient was aware of their randomization status, and envelopes were opened after induction of anaesthesia and towards the end of surgery" COMMENT ‐ It is not clear whether the sequence was concealed from the investigators as the authors do not mention that the envelopes were opaque |
| Blinding (performance bias and detection bias) Of outcome assessor to all outcomes | High risk | "It was not possible to double‐blind the study, as the observers needed to be able to see patients' airway in order to record the incidence of complications" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | COMMENT ‐ Though no explicit statement by authors, the outcomes are reported for 300 patients who were randomized |
| Selective reporting (reporting bias) | Low risk | COMMENT ‐ Though no explicit statement, the outcomes mentioned in methodology have been reported |