Heidari 2005.
| Methods | Prospective, randomized double‐blind study in 4 groups | |
| Participants | N = 156, ASA I‐II, age 18 to 65 years Short time elective surgery under general anaesthesia |
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| Interventions | Type of LMA: LMA Classic 4 groups ‐ Group 1: halothane anaesthesia and early removal of the LMA; Group 2: halothane anaesthesia and late removal of the LMA; Group 3: propofol anaesthesia and early removal of the LMA; Group 4: propofol anaesthesia and late removal of the LMA Early removal ‐ The LMA was removed at the end of surgery when patient was still receiving anaesthetic drug, N2O was discontinued and after inhalation of 100% O2 for at least 5 minutes, while the patient was still anaesthetized. Oral airway was inserted and finally anaesthetic drug was discontinued Late removal ‐ The LMA was removed in the presence of spontaneous eye opening, purposeful movement of extremities without any physical stimulation, and responding to verbal commands |
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| Outcomes | Laryngospasm Cough and straining Desaturation (SpO2 < 90%) Postoperative nausea and vomiting Bronchospasm Breath‐holding |
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| Notes | Induction ‐ fentanyl + lidocaine + thiopental Muscle relaxant ‐ atracurium Maintenance ‐ N2O + O2+ halothane/propofol |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "Patients randomly assigned in halothane and propofol group, using computerized generated random list. Then in each group, patients assigned randomly in early and late LMA removal groups" COMMENT ‐ The generation of allocation sequence for early and late LMA removal groups not mentioned (investigators could not be contacted at the correspondence address provided) |
| 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 | Low risk | In PACU, an anaesthesiologist who was blind to the type of anaesthetic drug and timing of LMA removal recorded study variables |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | COMMENT ‐ Outcomes reported for all 156 patients randomized |
| Selective reporting (reporting bias) | Low risk | COMMENT ‐ Though no explicit statement, the outcomes mentioned in methodology have been reported |