The laryngeal mask airways supreme (LMA-Supreme™) and protector (LMA-Protector™) are generally placed blindly, often resulting in a less than optimal position and vision-guided placement has been recommended. This prospective, randomized controlled study compared the efficacy of airway seal by measuring the oropharyngeal leak pressure in 100 surgical patients who underwent a variety of non-thoracic surgery under general anaesthesia, suitable with a supraglottic airway device. Patients were allocated to either the LMA-Supreme (n = 50) or LMA-Protector (n = 50) group. All insertions were performed under vision of a videolaryngoscope using an ‘insert-detect-correct-as-you-go’ technique with standardized corrective measures. Our primary endpoint, mean oropharyngeal leak pressure, was significantly higher in the LMA-Protector (31.7 ± 2.9 cm H2O) compared to the LMA-Supreme (27.7 ± 3.5 cm H2O) group (mean difference 4.0 cm H2O, 95% confidence interval (CI) 2.7–5.3 cm H2O, p < 0.001) after achieving a near-optimal fibreoptic position in the LMA-Protector (94%) and LMA-Supreme (96%) groups. No statistically significant differences were shown for secondary outcomes of alignment, number of insertion attempts and malpositions, and final anatomical position as scored by fibreoptic evaluation. Corrective manoeuvres were required in virtually all patients to obtain a correct anatomically positioned LMA. Position outcomes of the two devices were similar except for the proportion of procedures with folds in the proximal cuff (90% LMA-Supreme vs. 2% LMA-Protector, p < 0.001), the need for intracuff pressure adjustments (80% LMA-Supreme vs. 48% LMA-Protector, p = 0.001) and size correction (18% LMA-Supreme vs. 4% LMA-Protector, p = 0.025). In conclusion, a higher oropharyngeal leak pressure can be achieved with LMA-Protector compared to LMA-Supreme with optimal anatomical position when insertion is vision-guided.
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The authors thank our research nurses Heather Reynolds, Simon Holz, Molly Clarris and Lizanne Dalgleish for their expert assistance in this study.
This study was supported by departmental resources from the Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia only.
Compliance with ethical standards
Conflict of interest
On behalf of all authors, the corresponding author states that there are no competing interests.
The Royal Brisbane and Women’s Hospital Human Research Ethics Committee (HREC/15/QRBW/248, Chairperson Dr. Conor Brophy, dd 03.07.2015) approved the study. This study was registered with the Australia and New Zealand Clinical Trial Registry (ACTRN12615000783527).
Written patient’s informed consent was obtained from all participants.
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