Carron 2012.
| Methods | Single‐centre RCT. Padua, Italy | |
| Participants | 75 participants with BMI > 30 kg/m2 undergoing laparoscopic bariatric surgery. Excluded patients with symptoms of reflux, gastric ulcer or predicted difficult airway Mean age (SD): PLMA group 43.2 years (12.3); TT group 42.4 years (11.5) Mean BMI (SD): PLMA group 43.9 kg/m2(6.1); TT group 45.4 kg/m2 (4.3) % female: PLMA 83% TT 71% |
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| Interventions | 38 participants randomly assigned to the PLMA group and 37 to the TT group. 5 participants withdrawn from analysis, 35 in each group reported PLMA laryngeal mask airway company. Size 5. Positioned using digital technique ‐ standardized 3 excluded from PLMA group ‐ 2 failure of SAD placement and fibreoptic intubation, 1 laryngospasm on emergence No model of TT given. ID 7.5/8 mm. No details given of intubation technique. 2 excluded from TT group because of difficult intubation and prolonged surgery |
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| Outcomes | Change of airway device Hypoxic episodes in PACU (oxygen saturation < 92%) Oxygen saturation during operation (before, during and after carboperitoneum) and in the PACU Pulmonary aspiration of gastric contents Leak fraction and peak inspiratory pressure (before, during and after carboperitoneum) Laryngospasm on emergence Participant‐reported sore throat and hoarseness between end of surgery and discharge (8 to 9 hours after surgery) Placement－time and % successful first attempt |
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| Details of anaesthetic & ventilation | Premed midazolam 0.5 mg/kg and ranitidine 50 mg Preoxygenated for 2 minutes Anaesthesia induced with fentanyl 1 mcg/kg and propofol 2 to 3 mg/kg Maintenance: sevoflurane. 35/65 oxygen/air mixture, PEEP 5 cm H2O and PIP variable to obtain Vt exp of 10 mL/kg, respiratory rate of 12 breaths/min and inspiratory: expiratory ratio of 1:1 End of surgery: sevoflurane stopped and fresh gas flow increased to 10 L/min. Just before airway removal: lung ventilation manually assisted with continuous positive airway pressure during inspiration Airway removed when train‐of‐four ratio (TOFR) was 0.9 and the participant was awake, able to respond to simple commands, to sustain hand grip and move arms Breathing air in PACU |
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| Neuromuscular blockade & reversal given | Succinylcholine 1 mg/kg given to TT participants to facilitate intubation ‐ not to PLMA group After induction, single IV bolus of cisatracurium 0.15 mg/kg for NMB in TT group and 0.05 mg/kg in PLMA group. Additional IV cisatracurium 2 mg given if TOFR > 0.5 Muscle relaxation at end of surgery reversed with IV atropine 0.01 mg/kg IBW and neostigmine methylsulfate 0.04 mg/kg IBW if TOFR ≤ 0.9 |
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| Training and seniority of intubator | Two individuals with extensive experience (> 5000 uses with PLMA) randomly performed airway management and anaesthesia maintenance | |
| Notes | No funding sources named Authors emailed for additional information, and reply received 3/12/12 |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Computer–generated numbers" |
| Allocation concealment (selection bias) | Unclear risk | "Opaque sealed envelopes" used. Not described as consecutively numbered |
| Blinding of participants and personnel (performance bias) Change of airway device, time for placement, aspiration & laryngospasm. | High risk | Anaesthetist unblinded. Aim was to blind surgeon, but personal communication from authors indicates that this may have been difficult to maintain at all times |
| Blinding of participants and personnel (performance bias) Oxygen saturation | Low risk | Standardized ventilation protocol |
| Blinding of participants and personnel (performance bias) Post‐operative & patient‐reported outcomes | Low risk | Participants and nurses in PACU and surgical ward were blinded to allocation |
| Blinding of outcome assessment (detection bias) Change of airway device, time for placement, aspiration & laryngospasm | High risk | Standardized protocol for deciding failure of insertion of PLMA. but impossible to blind to allocation group |
| Blinding of outcome assessment (detection bias) Oxygen saturation | Unclear risk | Automatic measurements. Nurses in PACU blinded, but measurements in OR made by unblinded observers |
| Blinding of outcome assessment (detection bias) Post‐operative & patient‐reported outcomes | Low risk | Participants and observer were blinded to allocation |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | ITT analyses with participants excluded because of failed/difficult placement or laryngospasm included in relevant outcomes |
| Selective reporting (reporting bias) | Low risk | Outcomes outlined in Methods section of paper. Outcome of time to independent walking not reported on trial website |
| Other bias | Low risk | Participants in both groups similar at baseline |