Pre-warming the Streamlined Liner of the Pharynx Airway (SLIPA™) improves fitting to the laryngeal structure: a randomized, double-blind study

Abstract

BackgroundThe Streamlined Liner of the Pharynx Airway (SLIPA), a type of supraglottic airway, has a non-inflatable cuff that softens at body temperature to fit the laryngeal structure. We investigated whether pre-warming of SLIPA to body temperature may improve insertion parameters.MethodsNinety adult patients were assigned equally randomized to either Group W or Group R. Anesthesia was induced using propofol, fentanyl, and rocuronium. In Group W, the SLIPA was warmed to 37 ° C before insertion, whereas in Group R, it was inserted at room temperature. The insertion time, oropharyngeal leak pressure, postoperative throat pain, blood staining, regurgitation, number of attempts at insertion, and difficulty of insertion were compared between the two groups.ResultsThe insertion time was shorter in Group W than in Group R (3.60 [3.15–4.06] s vs. 6.00 [4.45–7.50] s; P < 0.001). Oropharyngeal leak pressure from the time of insertion until 3 min after insertion was significantly higher in Group W than in Group R (P < 0.05). Postoperative throat pain, measured using the visual analog scale, was lower in Group W than in Group R (0.00 [0.00–2.50] vs. 2.00 [0.00–4.50]; P = 0.006). The difficulty of insertion was lower in Group W than in Group R (P < 0.004). There were no significant differences in terms of blood staining, regurgitation, and number of attempts.ConclusionsPre-warming the SLIPA to body temperature has significant benefits compared to maintaining the device at room temperature. Specifically, insertion was easier, both insertion and fitting to the laryngeal structure could be performed more quickly, and the incidence of sore throat was reduced.Trial registrationClinical Research Information Identifier NCT01209000

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“…To attain a similar transpulmonary pressure, this “new” (higher) pressure therefore fills the SLIPA cuff with extra volume, resulting in a stronger seal [ 14 ]. Another proposed explanation for the rise in SLIPA’s OLP over-time is the softening of the device at body temperature, thereby producing a more effective perilaryngeal seal [ 15 ]. Such dynamic variation in the SLIPA’s OLP may provide unique benefits in situations where the patient’s airway pressure may increase intraoperatively e.g.…”

A randomized comparison of pediatric‐sized Streamlined Liner of Pharyngeal Airway™ and Laryngeal Mask Airway‐Unique™ in paralyzed children

“…We speculate that the higher rate of complications may result from the more rigid material of the SLIPA and direct trauma to the pharyngeal mucosa caused by the relatively large chamber of the SLIPA. According to Hyun Kang's study , prewarming the SLIPA to slightly soften the device could reduce throat pain, but this still did not reduce the incidence of blood staining. Except for the one case of laryngospasm, other complications were mild and did not require further treatment.…”

Prewarming non-inflatable cuff laryngeal mask for mechanical ventilation: A systematic review and meta-analysis with trial sequential analysis

“…Finally, 8 studies involving 683 patients were included in the meta-analysis. [6][7][8][16][17][18]31,32] A flow diagram of the literature selection process is shown in Figure 1.…”

“…[ 4 , 5 ] The thermoplastic nature of the non-inflatable cuff will become soft and match the laryngeal anatomy better as it reaches body temperature after insertion. [ 6 – 8 ]…”

“…Previous reports have shown that a non-inflatable cuff forms a more efficient seal around the larynx with a higher sealing pressure as the temperature rises to body temperature. [ 7 , 8 , 12 – 14 ]…”