Haemodynamic and Bispectral Index Response to Insertion of the Streamlined Liner of the Pharynx Airway (SLIPA™): Comparison with the Laryngeal Mask Airway

Abstract

The newly developed supralaryngeal airway Streamlined Liner of the Pharynx Airway (SLIPA™) has been compared successfully to the LMA™, but the haemodynamic response to its insertion has not been evaluated in a randomised study. We compared haemodynamic and Bispectral index (BIS) responses to insertion of the SLIPA™ with classic LMA™ after standardising the anaesthetic technique using BIS to monitor and control the anaesthetic depth. One hundred patients were randomised to receive either a classic LMA™ or SLIPA™ following induction with fentanyl and propofol titrated to a target BIS of 40 and compared heart rate, mean arterial pressure and BIS responses to insertion. There was a significant rise in mean arterial pressure from the pre-stimulus value (73.8 [10.6] mmHg, mean ± SD) at two and three minutes (P <0.05) following insertion of the LMA™ with maximum rise (80.8 [11.5] mmHg) seen at two minutes. There was a significant rise in mean arterial pressure from the pre-stimulus value (73.2 [12.6] mmHg) at one, two, three, four and five minutes (P <0.05) following insertion of the SLIPA™ with maximum rise (86.9 [15.1] mmHg) observed at three minutes. Mean arterial pressure was significantly higher (P <0.05) with SLIPA™ at two, three, four and five minutes. BIS increased significantly (P <0.05) at one, two, three, four and five minutes following insertion of both the devices, but there was no significant difference between the groups. There was a significantly higher (P=0.001) incidence of blood on the device with the SLIPA™ (20/50 vs. 6/50 with LMA™). Thus, insertion of SLIPA™ causes significantly higher blood-pressure response but similar BIS response compared to the LMA™.

The clinical effectiveness of the streamlined liner of pharyngeal airway (SLIPA™) compared with the laryngeal mask airway ProSeal™ during general anesthesia

“…When chosen correctly, the second attempt was successful. Previous studies outside of Korea [2,3,7,8] selected SLIPA size by matching the transverse diameter with the patient's thyroid cartilage. However, in our pilot tests, the SLIPA size chosen by this method was too large and insertion failed in many cases.…”

“…Airway management by PLMA is reported to decrease hemodynamic responses compared with endotracheal intubation [13]. Puri et al [3] reported that in SLIPA use, blood pressure and heart rate increase more than in PLMA uses, but this difference was not as significant as the difference in the use of endotracheal intubation. In this study, the PLMA group showed steady hemodynamic responses before and after insertion, whereas in the SLIPA group, 1 minute after insertion, the blood pressure and heart rate significantly increased to the maximum value.…”

“…To calcluate the sample size required for this study, time taken for intubation in a similar clinical setting was taken account [3]. A two-tailed α error of 5% and a β error of 20% was accepted in the detection of differences of 4 second in the time taken for intubation between the two groups.…”

“…1). Also, it can be inserted without the need for other devices, and as it is designed for single-use at a relatively cheaper price than the LMA, it has a lower risk of infection [3]. …”

Non-inflatable supraglottic airways

“…This finding raises again issues regarding inflatable or non-inflatable supraglottic airways and choice of sizes. Blood on the device is also more common with SLIPA (20/50 vs. 6/50 with LMA; P = 0.001) and SLIPA insertion increases blood pressure more than LMA [3]. …”