A comparison of the Supreme™ laryngeal mask airway with the Proseal™ laryngeal mask airway in anesthetized paralyzed adult patients: a randomized crossover study

Purpose

The Supreme? laryngeal mask airway (SLMA) is a new single-use advanced form of the Proseal? laryngeal mask airway (PLMA). This study tested the hypothesis that the SLMA is equally as effective as the PLMA as a supraglottic ventilatory device in anesthetized paralyzed adult patients.

Methods

Size 4 SLMAs and PLMAs were compared in a randomized crossover study involving 60 patients aged 21-75 yr and American Society of Anesthesiologists physical status I and II. Once the patients were anesthetized and paralyzed, the SLMA and the PLMA were inserted into each patient in random order. The primary outcome measure was the laryngeal seal pressure (LSP) at an intracuff pressure of 60 cm H₂O. Secondary outcome measures included the ease of inserting the laryngeal mask airway devices (LMADs) and the fibreoptic position of the airway tube.

Results

There was no statistically significant difference in LSP between the SLMA and the PLMA. The mean LSP was 19.6 ± 5.8 cm H₂O and 20.9 ± 6.7 cm H₂O for the SLMA and the PLMA, respectively. There was a similarity between the SLMA and the PLMA regarding the number of attempts required and the duration for insertion. However, fibreoptic positioning was better with the PLMA than with the SLMA (P < 0.0001).

Conclusion

The clinical performance of the SLMA as a ventilatory device is comparable with that of the PLMA, as illustrated by the similar LSPs. The inferior position of the SLMA airway tube compared with that of the PLMA does not affect its ease of ventilation.     

The proseal™laryngeal mask airway: a review of the literature

PURPOSE: To analyze and summarize the published literature relating to the ProSeal LMA (PLMA): a modification of the "classic LMA" (cLMA) with an esophageal drain tube (DT), designed to improve controlled ventilation, airway protection and diagnosis of misplacement. SOURCE: Articles identified through Medline and EMBASE searches using keywords "Proseal", "ProSeal" and "PLMA". Hand searches of these articles and major anesthetic journals from January 1998 to March 2005. PRINCIPAL FINDINGS: Searches identified 59 randomized controlled trials or clinical studies and 79 other publications. Compared to the cLMA, PLMA insertion takes a few seconds longer. First attempt insertion success for the PLMA is lower, but overall success is equivalent. Airway seal is improved by 50%. The DT enables early diagnosis of mask misplacement, allows gastric drainage, reduces gastric inflation and may vent regurgitated stomach contents. Evidence suggests, but does not prove, that the correctly placed PLMA reduces aspiration risk compared with the cLMA. PLMA use is associated with less coughing and less hemodynamic disturbance than use of a tracheal tube (TT). Comparative trials of the PLMA with other supraglottic airways favour the PLMA. Clinicians have extended the use of the PLMA inside and outside the operating theatre including use for difficult airway management and airway rescue. CONCLUSIONS: The PLMA has similar insertion characteristics and complications to other laryngeal masks. The DT enables rapid diagnosis of misplacement. The PLMA offers significant benefits over both the cLMA and TT in some clinical circumstances. These and clinical experience with the PLMA are discussed.     

Insertion of the ProSeal™ laryngeal mask airway is more successful with the Flexi-Slip™ stylet than with the introducer

Purpose

The ProSeal? laryngeal mask airway (PLMA?) may be difficult to insert because of its large soft cuff, even when using a dedicated introducer tool. The purpose of this study was to investigate whether introduction of a stylet (Flexi-Slip?) in the drainage tube improved insertion characteristics compared with the standard introducer.

Methods

In this randomized controlled trial, 160 adults were allocated randomly to either the Introducer group (n = 80) or to the Flexi-Slip stylet group (n = 80). In the Introducer group, the PLMA was inserted with an introducer as described in the manufacturer’s instructions. In the Flexi-Slip stylet group, a Flexi-Slip stylet was inserted into the drainage tube of the PLMA and bent to form a near 90° angle at the junction of the cuff and the airway tube. The primary outcome measurement was the success rate at first attempt. Insertion time, visible blood staining, and complications were also noted.

Results

Success at first attempt was more frequent with the Flexi-Slip stylet than with the introducer (100% vs 86%, respectively; P = 0.001). Overall time (mean ± standard deviation) taken for successful placement was shorter with the Flexi-Slip stylet than with the introducer (19.9 ± 5.6 sec vs 28.4 ± 15.2 sec, respectively; P < 0.001). The incidences of blood staining and postoperative sore throat were lower in the Flexi-Slip stylet group than in the Introducer group (4% vs 15%, respectively; P = 0.015 and 8% vs 23%, respectively; P = 0.008).

Conclusion

Insertion of the PLMA with a Flexi-Slip stylet has a higher success rate at first attempt, requires less time, and results in fewer airway complications than the introducer technique.     

Improved esophageal patency when inserting the ProSeal™ laryngeal mask airway with an Eschmann™ tracheal tube introducer

Purpose

We hypothesized that a more accurate alignment of the tip of the drain tube with the upper esophageal opening would be achieved in adult patients, as confirmed by fibreoptic bronchoscopy, by placing the ProSeal? laryngeal mask airway (PLMA) by means of guiding it over an Eschmann? tracheal tube introducer, commonly know as a gum elastic bougie (GEB), that was previously inserted into the esophagus, rather than by placing the PLMA with a curved metal introducer (IT).

Methods

Seventy-five adult elective surgery patients, whose airway management involved a PLMA, were randomly allocated to either the GEB- or IT-guided techniques. After inserting the PLMA, alignment of the tip of the drain tube relative to the esophageal opening was verified by a fibrescope introduced through the drain tube. Placing the fibrescope through the PLMA identified the glottic structures. The primary endpoint indicating the proper alignment of the tip of the drain tube of the PLMA with the upper esophageal opening was the ability to pass the fibrescope into the esophagus through the drain tube by a distance >35 cm without obstruction and the ability to simultaneously visualize the esophageal mucosa.

Results

The overall success rates of PLMA insertion were similar in the GEB and IT groups. However, the mean airway insertion times were longer with the GEB than with the IT-PLMA. The GEB group achieved proper alignment of the drain tube and the upper esophageal opening more frequently than the IT group (97% confidence interval (CI₉₅) 91.5–100% vs 81% CI₉₅ 68.5–93.5% of subjects, respectively; P = 0.027). When the GEB was used to place the PLMA, the patients’ vocal cords were visualized more frequently than when the IT technique was used (100% vs 73% CI₉₅ 58.9–87.1% of subjects, respectively; P = 0.003).

Conclusion

Fibreoptic bronchoscopy confirmed that GEB is superior to the IT technique in ensuring precise alignment of the tip of the drain tube of the PLMA with the upper esophageal opening. Accurate positioning may better preserve gastroesophageal drainage function of the PLMA.     

Insertion of the ProSeal™ laryngeal mask airway is more successful with the 90° rotation technique

Purpose

The 90° rotation technique for inserting the ProSeal? laryngeal mask airway (PLMA) in anesthetized paralyzed patients was compared with the index finger insertion technique.

Methods

One hundred twenty Asian adult patients were randomly allocated to either a standard technique group or a rotation technique group. A PLMA size 4 was used for women and size 5 was used for men. In the standard technique group (n = 60), the PLMA was inserted using the index finger. In the rotation technique group (n = 60), the entire cuff of the PLMA was placed in the patient’s mouth in a midline approach without finger insertion, rotated 90° counter clockwise around the patient’s tongue, advanced and then rotated back until resistance was felt. The primary outcome was success at first insertion. Secondary outcome measures were insertion time and complications.

Results

The success rate at first insertion was greater for the rotation technique group than for the standard technique group (100% vs 83%, respectively; P = 0.003), and less time was required (11 ± 3 sec vs 19 ± 16 sec, respectively; P = 0.03). The incidence of postoperative sore throat was lower for the rotation technique group than for the standard technique group (12% vs 33%, respectively; P = 0.009), and blood staining on the PLMA was less (8% vs 40%, respectively; P < 0.001).

Conclusion

The 90° rotation technique for inserting the PLMA is more successful than the standard index finger insertion technique. It is associated with fewer side effects, such as blood on the PLMA and sore throat, which suggests it causes less pharyngeal trauma. (Clinical trial registration number: NCT00966186).     

Tongue numbness following laryngeal mask airway Supreme™ and i-gel™ insertion: two case reports

We present two cases of transient lingual nerve injury that were associated with the use of a laryngeal mask airway Supreme? (The Laryngeal Mask Company, Singapore) during lumbar discectomy in a 43‐year‐old female and i‐gel? (Intersurgical, Berkshire, UK) during ovum pick up in a 33‐year‐old female. They presented with numbness at the tip of their tongues and spontaneously and fully recovered 2 weeks after their operations.     

Comparison of blind tracheal intubation through the intubating laryngeal mask airway (LMA Fastrach™) and the Air-Q™

This study assessed two disposable devices, the LMA Fastrach^TM and the newly developed supraglottic airway device, the Air‐Q^TM, as a conduit for tracheal intubation in 154 healthy adults undergoing elective surgery. Using a non‐inferiority approach, the primary outcome measure was successful tracheal intubation within two blind insertion attempts. Successful blind intubation after two attempts was achieved in 75/76 (99%) of the patients in the LMA Fastrach group vs 60/78 (77%) in the Air‐Q group (95% CI for the difference 12–32%, p < 0.0001). Fibreoptic intubation was used to assist the third attempt. The rate of successful intubation after three attempts was 100% in the LMA Fastrach group and 95% in Air‐Q group. The single‐use LMA Fastrach appears superior compared with the Air‐Q, as a conduit to facilitate blind tracheal intubation.     

The 90° rotation technique improves the ease of insertion of the ProSeal™ laryngeal mask airway in children

Background

A previous study using a 180° rotation to insert the ProSeal? laryngeal mask airway (LMA ProSeal) in children did not show improvement over the standard technique. We used a 90° rotation technique to insert the LMA ProSeal in pediatric patients and compared ease of insertion and pharyngeal trauma with the standard technique.

Methods

This prospective randomized controlled study included 126 patients aged three to nine years. Anesthesia was induced with thiopental and rocuronium, and the LMA ProSeal used in the study ranged in size from 2 to 3 depending on the patient’s body weight. In the control group (n = 63), the LMA ProSeal was inserted using the index finger. In the rotation group (n = 63), the entire cuff of the LMA ProSeal was placed in the patient’s mouth without finger insertion and rotated 90° counter clockwise around the tongue. The LMA ProSeal was then advanced and rotated back until resistance was felt. The primary outcome was the insertion success rate at first attempt.

Results

The success rate of insertion at first attempt was higher with the rotation technique than with the standard technique (97% vs 70%, respectively; P < 0.001) and the insertion time was shorter (16 ± 6 sec vs 30 ± 24 sec, respectively; P < 0.001). Mean blood pressure after LMA ProSeal insertion increased significantly in the control group (62 ± 12 to 69 ± 17 mmHg; P = 0.01), but not in the rotation group. The incidence of blood staining was lower in the rotation group than in the control group (10% vs 25%, respectively; P = 0.03), but the incidence of sore throat was not significantly different (24% vs 22%, respectively; P = 0.9).

Conclusions

The 90° rotation technique improves ease of insertion of the LMA ProSeal in children, and it decreases the risk of pharyngeal trauma. (ClinicalTrials.gov number, NCT01076725)     

Does the ProSeal laryngeal mask airway prevent aspiration of regurgitated fluid?

In this randomized, cross-over cadaver study, we determined whether a new airway device, the ProSeal laryngeal mask airway (PLMA; Laryngeal Mask Company, Henley-on-Thames, UK), prevents aspiration of regurgitated fluid. We studied five male and five female cadavers (6-24 h postmortem). The infusion set of a pressure-controlled, continuous flow pump was inserted into the upper esophagus and ligated into place. Esophageal pressure (EP) was increased in 2-cm H(2)O increments. This was performed without an airway device (control) and over a range of cuff volumes (0-40 mL) for the classic laryngeal mask airway (LMA), the PLMA with the drainage tube clamped (PLMA clamped) and unclamped (PLMA unclamped). The EP at which fluid was first seen with a fiberoptic scope in the hypopharynx (control), above or below the cuff, or in the drainage tube, was noted. Mean EP at which fluid was seen without any airway device was 9 (range 8-10) cm H(2)O. EP at which fluid was seen was always higher for the PLMA clamped and LMA compared with the control (all, P<0.0001). The mean EP at which fluid was seen for the PLMA unclamped was similar to the control at 10 (range 8-13) cm H(2)O. For the PLMA unclamped, fluid appeared from the drainage tube in all cadavers at 10-40 mL cuff volume and in 8 of 10 cadavers at zero cuff volume. Mean EP at which fluid was seen above the cuff was similar for the PLMA clamped and LMA at 0-30 mL cuff volume, but was higher for PLMA clamped at 40-mL cuff volume (81 vs 48 cm H(2)O, P = 0.006). Mean EP at which fluid was seen below the cuff was similar at 0-10 mL cuff volume, but was higher for the PLMA clamped at 20, 30, and 40 mL cuff volume (62, 68, 73 vs. 46, 46, 46 cm H(2)O, respectively, P<0.04). For the PLMA clamped and the LMA, fluid appeared simultaneously above and below the cuff at all cuff volumes. We concluded that in the cadaver model, the correctly placed PLMA allows fluid in the esophagus to bypass the pharynx and mouth when the drainage tube is open. Both the LMA, and PLMA with a closed drainage tube, attenuate liquid flow between the esophagus and pharynx. This may have implications for airway protection in unconscious patients.     

Oropharyngeal leak pressure with the laryngeal mask airway Supreme™ at different intracuff pressures: a randomized controlled trial

Background

A higher oropharyngeal leak pressure (OLP) is a marker of efficacy and safety when using laryngeal mask airway devices. The new disposable laryngeal mask airway (LMA?) Supreme? has lower OLP compared with the LMA ProSeal?. Increased intracuff pressure of laryngeal mask airway devices may improve OLP but may result in more postoperative pharyngolaryngeal adverse events. This study was designed to compare the OLP of the LMA Supreme at varying intracuff pressures.

Methods

One hundred and twenty-three patients were divided randomly into three groups. General anesthesia was standardized using a propofol-fentanyl induction and desflurane in air-oxygen for maintenance. Intracuff pressures of the LMA Supreme were adjusted to 80 cm H₂O, 60 cm H₂O, and 40 cm H₂O according to group allocation. The primary outcome was OLP. Secondary outcomes included postoperative pharyngolaryngeal adverse events and the satisfaction scores of patients and anesthesiologists. The OLP was compared amongst groups using analysis of variance with Bonferroni correction. All reported P values are two-sided.

Results

The OLP with an intracuff pressure of 80 cm H₂O was significantly higher compared with 60 cm H₂O and 40 cm H₂O (26 [6] vs 20 [6] vs 18 [5] cm H₂O, respectively; P < 0.001). The incidence of postoperative pharyngolaryngeal adverse events (P = 0.6), patient satisfaction scores (P = 0.2), and anesthesiologist satisfaction scores (P = 0.8) were comparable amongst the three groups.

Conclusion

An intracuff pressure of 80 cm H₂O with the LMA Supreme is associated with a higher OLP compared with 60 cm H₂O or 40 cm H₂O without a greater incidence of postoperative pharyngolaryngeal adverse events. For a superior glottic seal when using the LMA Supreme, we recommend intracuff pressures up to 80 cm H₂O.     

Use of the intubating laryngeal mask airway: are muscle relaxants necessary?

BACKGROUND: The intubating laryngeal mask airway (ILMA) is designed to facilitate blind tracheal intubation. The effect of a muscle relaxant on the ability to perform tracheal intubation through the ILMA device has not been previously evaluated. This randomized, double-blind, placebo-controlled study was designed to evaluate rocuronium, 0.2 or 0.4 mg/kg administered intravenously, on the success rate and incidence of complications associated with ILMA-assisted tracheal intubation. METHODS: A total of 75 healthy patients were induced with propofol 2 mg/kg and fentanyl 1 microg/kg intravenously. After insertion of the ILMA device, patients were administered either saline, rocuronium 0.2 mg/kg, or rocuronium 0.4 mg/kg in a total volume of 5 ml. At 90 s after administration of the study drug, tracheal intubation was attempted using a disposable polyvinyl tube. If unsuccessful, a reusable silicone tube was tried. In addition to recording the time and number of attempts required to secure the airway, the incidence of complications during placement of the tracheal tube and removal of the ILMA were noted. RESULTS: Tracheal intubation was successful in 76-96% of the patients. The overall success rates and times required to secure the airway were similar in all three treatment groups. The high-dose rocuronium group experienced less patient movement (8 vs. 28 and 48%) and coughing (12 vs. 20 and 52%) than the low-dose rocuronium and saline groups, respectively. Use of rocuronium was also associated with a dose-related decrease in the requirement for supplemental bolus doses of propofol during intubation and removal of the ILMA device. CONCLUSIONS: Use of rocuronium did not significantly improve the success rate in performing tracheal intubation through the ILMA. However, it produced dose-related decreases in coughing and movement after tracheal intubation and reduced difficulties associated with removal of the ILMA device.