A randomised controlled trial comparing two insertion techniques for the Laryngeal Mask Airway Flexible™ in patients undergoing dental surgery

Abstract

SummaryThe Laryngeal Mask Airway Flexible TM (LMA Flexible) has been widely utilised for dental, ophthalmology and otorhinolaryngology-related procedures. Our study evaluates two different techniques of inserting the LMA Flexible for patients undergoing day-case dental surgery. One hundred and eight patients were randomly assigned into two groups based on the LMA Flexible insertion technique -either laryngoscopy-guided (n = 54) or digital manipulation (standard technique; n = 54). Patient and airway characteristics were recorded before induction of anaesthesia. The primary outcome was success rate at first insertion. Other outcomes assessed included fibreoptic assessment of laryngeal mask airway placement, haemodynamic changes, need for airway adjustment during surgery and sore throat. The success rate of insertion on the first attempt was higher for the laryngoscopy-assisted technique compared with the standard technique (96.3% vs 81.5%, respectively, p < 0.05). Fibreoptic assessment showed that the former group had better placement of the laryngeal mask airway than the latter (59.3% vs 37% p < 0.05). There were no significant differences between the two groups for haemodynamic changes. Sore throat was more common in the group with the standard technique (35.2% vs 16.7%, p < 0.05). Our study suggests the use of the laryngoscope to guide insertion of the LMA Flexible for dental surgery is a better option compared with the standard technique of digital manipulation. Laryngeal Mask Co. Limited, Mahe, Seychelles) has been widely used for dental, head and neck-related surgery [1][2][3]. The cuff portion is identical to the classic version of the LMA, but the LMA Flexible has a long and nonrigid flexometallic tube, which may make insertion more challenging. This unique design allows greater movement of the tube without displacement of the cuff or loss of seal. The head and neck may be turned with a decreased risk of airway dislodgement during surgery. Studies have detailed its usefulness compared with tracheal intubation in dental day surgery patients [4,5], but few studies have examined different techniques of insertion. Therefore, we evaluated the use of a laryngoscopy-guided technique as an alternative to the standard technique of digital manipulation for insertion of the LMA Flexible, in adult patients presenting for day-case dental surgery.

Supraglottic Airway Devices: the Search for the Best Insertion Technique or the Time to Change Our Point of View?

“…This difference might be explained with simple observations: PLMA has thicker (double) cuff, it is silicon made (resulting in higher friction against tongue and palatal and hypopharyngeal mucosa) and it comes with silicon-based wire-reinforced flexible airway conduit, which reduces the amount of force transmission from point of application (bite-block or tube) to the tip. This last issue might also explain the steeper learning curve observed for Flexible LMA TM (FLMA; Teleflex Medical, Dublin, Ireland) and Aura-flex TM (Ambu A/S, Ballerup, Denmark) when compared with other SADs (34). Similar conclusions might arise for devices hosting a larger cuff or a reservoir for further protection from gastric content regurgitation (Figure 4), such as Baska Mask TM (35) (BVLM Pty Ltd, Strathfield, Australia) and PrLMA, or for SADs designed for specific endoscopic procedures, such as LMA Gastro TM (36) (GLMA; Teleflex Medical, Dublin, Ireland) and Gastro-Laryngeal Tube TM (37) (VBM Medizintechnik GmbH, Sulz am Neckar, Germany) provided with an embedded endoscope-dedicated channel ( Figure 5).…”

ProSeal laryngeal mask airway placement: A comparison of blind versus direct laryngoscopic insertion techniques

“…These findings were consistent with findings of Choo et al . [11] where either technique did not produce any significant differences in the hemodynamic parameters at 0, 1, and 5 min postinduction. In contrast, Chandan et al .…”

“…[11] who evaluated two different techniques of inserting the LMA. Flexible for patients undergoing day-care dental surgery reported LMA placement revealed better scores with the laryngoscopy-guided technique than with the standard technique using fiber-optic assessment.…”

“…In contrast, Choo et al . [11] reported slightly higher incidence of sore throat in the group of patients who had the LMA flexible inserted using the standard technique of digital manipulation.…”

Comparison of Insertion of the Modified i-gel Airway for Oral Surgery With the LMA Flexible: A Manikin Study

“…16,17 This success rate rises to around 90% when the device is combined with a pediatric tracheal tube, stylet, or other introducer. 13,16,17 However, Casey et al 18 reported a case in which combined insertion with a Bosworth introducer caused a severe abscess on the posterior wall of the pharynx, suggesting that combining the LMA Flexible with an introducer has the potential to cause pharyngeal trauma. The present study showed the rate of successful insertions with the modified i-gel airway to be around 90%, which is just as high as that of the original i-gel airway and the LMA Flexible combined with an introducer.…”