Randomized Evaluation of the Single-use SoftSeal™ and the Re-useable LMA Classic™ Laryngeal Mask

Comparison of the AMBU® Laryngeal Mask and the LMA Classic in Anaesthetised, Spontaneously Breathing Patients

There may be a role for single-use laryngeal mask airways with concerns about inability to adequately sterilise laryngeal mask airways to eradicate prion proteins. A single-blinded prospective randomised controlled trial was conducted to compare the clinical performance of the single-use AMBU®LMA with the reuseable LMA Classic. There was no difference in time to insertion, successful insertion at first attempt, oropharyngeal leak pressure, haemodynamic response to insertion or complications of placement. The AMBU®LMA was easier to insert. There was a suggestion of reduced postoperative sore throat and pharyngeal trauma for the AMBU® LMA group. The AMBU®LMA is a viable alternative to the LMA Classic for airway management in spontaneously breathing patients.

Evaluation of the SLIPA™ (Streamlined Liner of the Pharynx Airway), a Single Use Supraglottic Airway Device, in 60 Anaesthetized Patients Undergoing Minor Surgical Procedures

The Streamlined Liner of the Pharyngeal Airway, SLIPA™ (Hudson RCI) is a new disposable supraglottic airway device that has no inflatable cuff and has features designed to reduce aspiration risk. This study aimed to assess the insertion success and effectiveness of the SLIPA™ in 60 patients who presented for elective surgery. Ethics committee approval was obtained. Patients were excluded if they were less than 18 years, had not provided written consent or were at risk of pulmonary aspiration. The first 20 SLIPA™ were inserted by the principal investigator (Group A) followed by another 40 inserted by medical officers and anaesthetists of varying experience (Group B). Twenty-one males and 39 females were recruited into the study. Median time to ventilation was 20.4 seconds in Group A (range 12.9-109) and 24.8 seconds in Group B (range 8.2-82.5). Overall success rate was 100% in Group A and 92.5% in Group B. The lowest recorded SpO2 was 91% in Group B. The incidence of blood and sore throat score >3 (0-10 scale) was 23% and 7% respectively (Groups A and B). Group B reported that use of the device was very easy in 16%, easy in 76%, difficult in 5%, and very difficult in 3%. The SLIPA™ proved to be a reliable airway providing adequate ventilation in both spontaneous breathing and assisted respiration. Most users found the SLIPA™ to be easy or very easy to use.

Comparison of the Re-usable LMA Classic™ and Two Single-use Laryngeal Masks (LMA Unique™ and SoftSeal™) in Airway Management by Novice Personnel

In a single-blind randomized trial, three types of laryngeal masks: the reusable LMA Classic™, the single-use LMA Unique™ and SoftSeal™ were inserted by novice medical officers in anaesthesia. Five successive attempts were undertaken with each mask type. The order of the mask type insertion was randomly selected. Mean (SD) insertion times for LMA Classic™, LMA Unique™ and Soft Seal™ were 32.9 (12.3), 39.6 (23.4) and 49.4 (50.4) seconds respectively. Differences were only significant between LMA Classic™ and SoftSeal™ (P=0.012). There were no significant differences in first attempt success rates (LMA Classic™ 80%, LMA Unique™ 77% and SoftSeal™ 62%). The SoftSeal™ was most frequently associated with blood on the mask (32%) compared to the LMA Unique™(9%) and LMA Classic™ (6%). Sore throat was experienced in 14% of patients in the LMA Unique™ group versus 41% and 42% in the LMA Classic™ and SoftSeal™ groups respectively. Mean±SD oropharyngeal leak pressure was significantly higher in the SoftSeal™ (21±6 cmH2O) compared to the LMA Classic™ (17±7 cmH2O) and LMA Unique™ (16±6 cmH2O).

Novice medical doctors can be taught to insert disposable laryngeal masks. The SoftSeal™ took longer to insert, which resulted in a higher incidence of blood on the mask, but success rates did not differ. The LMA Unique™ was associated with the lowest incidence of sore throat in the immediate postoperative period. A higher oropharyngeal leak pressure with the SoftSeal™ may indicate improved airway seal and protection against aspiration.

Comparison of Disposable and Reusable Laryngeal Mask Airways in Spontaneously Ventilating Adult Patients

Recent studies have indicated that despite stringent sterilization processes, the reusable silicone laryngeal mask airway (LMA) has the potential for disease transmission through residual biological debris. As a result, a polyvinyl chloride (PVC) disposable LMA has been introduced.

This randomized trial involved 138 spontaneously ventilating adult patients who underwent elective surgery requiring airway management with an LMA to determine whether there is a clinical difference between the disposable Portex® LMA (PLMA) and the standard reusable LMA in terms of ease of insertion, intra-operative cuff pressures and postoperative incidence of sore throat.

There was no significant difference in first attempt insertion success rates (79% vs 84%) or difference in the incidence of postoperative sore throat observed between the two groups. Cuff pressure increases with nitrous oxide anaesthesia were significantly larger with the reusable LMA. The disposable PLMA provided a suitable airway in spontaneously ventilating patients without the risk of disease transmission inherent in a reusable device.

The effect of intraoperative remifentanil infusion on analgesic requirements after laparoscopic cholecystectomy

BACKGROUND

This study was designed to evaluate the effect of intraoperative remifentanil infusion on postoperative analgesics requirements after laparoscopic cholecystectomy.

METHODS

One hundred adult patients scheduled for elective laparoscopic cholecystectomy were enrolled. Patients were randomly allocated to 2 groups to receive sevoflurane with remifentanil infusion (Group R) or not (group C). Sevoflurane concentration and remifentanil dose were adjusted to maintain BIS 40-60 and blood pressure within 20% of the preoperative value, respectively. We assessed the pain intensity by using the four-point verbal rating scale (VRS) (0 = no pain. 1 = slight pain, 2 = moderate pain, 3 = intense or severe pain) at 15 min intervals for 1 hour in recovery room and then at 3-h intervals for 24 h in surgical ward. The analgesic medication was given when VRS score was > or =2 or patients requested it.

RESULTS

There were no differences between the two groups with respect to the requirements for postoperative analgesics in recovery room and surgical ward.

CONCLUSIONS

Continuous remifentanil infusion (0.09 +/- 0.05 ug/kg/min) during laparoscopic cholecystectomy does not cause hyperalgesia and more analgesic requirements.

The Soft Seal disposable laryngeal mask airway in adults: comparison of two insertion techniques without intra-oral manipulation

We investigated whether insertion of the disposable Soft Seal laryngeal mask airway (SSLM) was successful without intra-oral digital manipulation. One hundred patients undergoing anaesthesia using the SSLM were randomly assigned into two groups. Insertion was performed by either a direct or a rotational technique, both without intra-oral digital manipulation. The primary outcome measure was successful insertion at first attempt. Other outcomes included insertion time, fibreoptic assessment of the airway view and airway morbidity. The first attempt success rate was higher (98%) with the direct technique than with the rotational technique (75%; p = 0.002) but insertion time was faster with the latter method (mean [range] 15 [8-50] s) than with the direct method (20 [8-56] s; p = 0.035). Fibreoptic assessment and airway morbidity were similar in both groups. We conclude that the SSLM can be successfully inserted without intra-oral digital manipulation.

Randomized comparison of the SLIPA (Streamlined Liner of the Pharynx Airway) and the SS-LM (Soft Seal Laryngeal Mask) by medical students

OBJECTIVE

The aim of the study was to compare the Streamlined Liner of the Pharynx Airway (SLIPA; Hudson RCI), a new supraglottic airway device, with the Soft Seal Laryngeal Mask (SS-LM; Portex) when used by novices.

METHODS

Thirty-six medical students with no previous airway experience, received manikin training in the use of the SLIPA and the SS-LM. Once proficient, the students inserted each device in randomized sequence, in two separate patients in the operating theatre. Only two insertion attempts per patient were allowed. Students were assessed in terms of: device preference; success or failure; success at first attempt and time to ventilation.

RESULTS

Sixty-seven per cent of the students preferred to use the SLIPA (95% confidence interval 49-81%). The SLIPA was successfully inserted (one or two attempts) in 94% of patients (34/36) and the SS-LM in 89% (32/36) (P = 0.39). First attempt success rates were 83% (30/36) and 67% (24/36) in the SLIPA and SS-LM, respectively (P = 0.10). Median time to ventilation was shorter with the SLIPA (40.6 s) than with the SS-LM (66.9 s) when it was the first device used (P = 0.004), but times were similar when inserting the second device (43.8 s vs 42.9 s) (P = 0.75).

CONCLUSIONS

In the present study novice users demonstrated high success rates with both devices. The SLIPA group achieved shorter times to ventilation when it was the first device they inserted, which might prove to be of clinical significance, particularly in resuscitation attempts. Although the Laryngeal Mask has gained wide recognition for use by both novice users and as a rescue airway in failed intubation, the data presented here suggest that the SLIPA might also prove useful in these areas.

Comparison of LMA Unique, Ambu laryngeal mask and Soft Seal laryngeal mask during routine surgical procedures

BACKGROUND AND OBJECTIVE

This study was performed to compare three disposable airway devices, the LMA Unique (LMA-U), the Ambu laryngeal mask (Ambu LM) and the Soft Seal laryngeal mask (Soft Seal LM) for elective general anaesthesia during controlled ventilation in non-paralysed patients.

METHODS

One hundred and twenty ASA I-III patients scheduled for routine minor obstetric surgery were randomly allocated to the LMA-U (n = 40), Ambu LM (n = 40) or Soft Seal LM (n = 40) groups, respectively. Patients were comparable with respect to weight and airway characteristics. A size 4 LMA was used in all patients and inserted by a single experienced anaesthesiologist. Oxygenation, overall success rate, insertion time, cuff pressure and resulting airway leak pressure were determined as well as a subjective assessment of handling and the incidence of sore throat, dysphagia and hoarseness.

RESULTS

Time of insertion was shortest with the Ambu LM, while failure rates were comparable with the LMA-U, the Ambu LM and the Soft Seal LM (median 19 s; range 8-57 s; success rate 100% vs. 14; 8-35; 97% vs. 20; 12-46; 95%). Insertion was judged 'excellent' in 75% of patients in the LMA-U group, in 70% of patients in Ambu LM group and in 65% of patients in the Soft Seal LM group. There was no difference between devices with respect to postoperative airway morbidity at 6 h or 24 h following surgery.

CONCLUSIONS

All three disposable devices were clinically suitable with respect to insertion times, success rates, oxygenation, airway and leak pressures, as well as to subjective handling and postoperative airway morbidity.

New airways for resuscitation?

Over the last 15 years supraglottic airway devices (SADs), most notably the classic laryngeal mask airway (LMA) have revolutionised airway management in anaesthesia. In contrast for resuscitation, both in and outside hospital, facemask ventilation and tracheal intubation remain the mainstays of airway management. However there is evidence that both these techniques have complications and are often poorly performed by inexperienced personnel. Tracheal intubation also has the potential to cause serious harm or death through unrecognised oesophageal intubation. SADs may have a role in airway management for resuscitation as first responder devices, rescue devices or for use during patient extraction. In particular they may be beneficial as the level of skill required to use the device safely may be less than for the tracheal tube. Concerns have been expressed over the ability to ventilate the lungs successfully and also the risk of aspiration with SADs. The only SADs recommended by ILCOR in its current guidance are the classic LMA and combitube. Several SADs have recently been introduced with claims that ventilation and airway protection is improved. This pragmatic review examines recent developments in SAD technology and the relevance of this to the potential for using SADs during resuscitation. In addition to examining research directly related to resuscitation both on bench models and in patients the review also examines evidence from anaesthetic practice. SADS discussed include the classic, intubating and Proseal LMAs, the combitube, the laryngeal tube, laryngeal tube sonda mark I and II and single use laryngeal masks.

A comparison of the Soft Sealtm disposable and the Classic re-usable laryngeal mask airway*

Many new supraglottic airway devices have been recently introduced, their development motivated by the need for a single-use equivalent to the original re-usable laryngeal mask airway. We performed a randomised cross-over study in spontaneously breathing patients comparing the re-usable Laryngeal Mask Airway-Classic (LMA) and the disposable Soft Seal Laryngeal Mask in sizes 3, 4 and 5. Sixty patients had an LMA and a disposable laryngeal mask placed in random order. The primary outcome was first attempt insertion success rate. Ease of insertion was similar in both groups and there was no difference in first attempt success rates (96% with LMA and 92% with disposable laryngeal mask). The disposable laryngeal mask required significantly less air to inflate the cuff to produce a seal (10 [10-25] ml with disposable laryngeal mask and 15 [10-30] ml with laryngeal mask) and the cuff pressure produced was significantly lower (35 [20-80] cmH(2)O with disposable laryngeal mask and 75 [20-120] cmH(2)O with LMA). Data are median and range. We conclude that the disposable laryngeal mask is an acceptable alternative to the re-usable LMA.

A randomised comparison of the Portex Softseal laryngeal mask airway with the LMA-Unique during anaesthesia

We have compared the performance of the single use laryngeal airway devices Softseal and LMA-Unique in a randomised comparative trial in anaesthetised healthy patients who did not receive neuromuscular blockade. Primary outcome was success of airway placement. Secondary outcomes included manipulations and complications during use, ease of insertion, airway and fibreoptic assessment of airway positioning, and complications postoperatively. We planned to study 300 patients but interim analysis demonstrated the study should be stopped after 100 patients. During insertion the Softseal required more attempts for successful insertion (p = 0.041), more manipulations (p < 0.0001) and caused more complications (p = 0.048). Failure of placement occurred in five cases with the Softseal and none with the LMA-Unique (p = n/s). Two Softseal needed to be removed during maintenance because of airway obstruction, giving an overall failure rate of seven (p = 0.013). Serial tests of positioning favoured the LMA-Unique (p = 0.012). Ventilation was more successful in the LMA-Unique group but the difference was not significant (p = 0.051). Seal pressure was higher with the Softseal (26.5 vs. 20.5 cmH(2)O, p = 0.005). Fibreoptic view via the devices was not statistically significantly different. During maintenance of anaesthesia more complications arose with the Softseal (p = 0.03). Anaesthetist ratings of ease of insertion and overall usefulness favoured the LMA-Unique (p < 0.0001 and p = 0.024, respectively). After anaesthesia, sore throat occurred more frequently and was more severe in those patients anaesthetised with a Softseal both in recovery (p = 0.015) and at 24 h (p = 0.012). We conclude that the Softseal performs less well and causes more complications than the LMA-Unique.

A Multicenter Study of the Ambu?? Laryngeal Mask in Nonparalyzed, Anesthetized Patients

We designed this multicenter trial to evaluate the performance and safety of the Ambu laryngeal mask, a new disposable supraglottic airway device, in patients scheduled for elective surgery. One-hundred-eighteen nonparalyzed, anesthetized patients (ASA physical status I-II, age, 18-65 yr, body mass index, 18-30 kg/m(-2)) receiving total IV anesthesia were included in this study. After device insertion, fiberoptic position and oropharyngeal leak pressure were determined at an intracuff pressure of 60 cm H2O. Ease of ventilation was determined by controlling ventilation at 6 mL/kg tidal volume. Any complications were noted and recorded. Device placement was successful in all patients on the first or second attempt (92.4% or 7.6%, respectively) with an insertion time (removal of face mask until first tidal volume) of 44.9 +/- 37.91 s. Adequate ventilation was achieved in all patients and the vocal cords could be visualized by fiberoptic endoscopy in 91.5% of patients. Oropharyngeal leak pressures were 24.1 +/- 5.44 cm H2O. Blood was detected on the device in 8.5% of patients. Complications and patient complaints were minor and quickly resolved. The Ambu laryngeal mask is easy and quick to insert and provides a safe and efficient seal during positive pressure ventilation in nonparalyzed patients scheduled for elective surgery.

Randomised, crossover comparison of the single-use SoftSeal?and the LMA Unique?laryngeal mask airways

We performed a randomised, crossover, single-blind trial among 168 patients, to compare the single-use SoftSeal and LMA Unique laryngeal mask airways in spontaneously breathing adults. Size-3 and -4 laryngeal mask airways, inserted by experienced anaesthetists, performed equivalently for successful first-time placement (148 (91%) vs 155 (96%) for the SoftSeal and LMA Unique, respectively). The SoftSeal was more often rated as difficult to insert (27 (17%) vs 4 (3%); p < 0.001) and was more likely to show evidence of mucosal trauma after the first insertion (14 (10%) vs 5 (4%); OR 1.3 (95% CI 1.3-11.3); p < 0.05). The fibreoptic view of the larynx was better through the SoftSeal (vocal cords not visible in 27 (17%) vs 44 (27%); p < 0.05) and it more frequently provided a ventilation seal at 20 cmH(2)O (93 (59%) vs 62 (39%); OR 2.15 (CI 1.44-3.21); p < 0.001). In contrast to the LMA Unique(trade mark), its cuff pressure did not increase during nitrous oxide anaesthesia (median (IQR [range]) decrease 3 (- 20-23 [-40-94]) cmH(2)O vs increase of 16 (-2-39 [-54-112]) cmH(2)O; p < 0.01). Both devices were equivalent for the success of first-time insertion and performed satisfactorily clinically. There were some performance differences, but either appears suitable for airway management in spontaneously breathing patients.

Securing the prehospital airway: a comparison of laryngeal mask insertion and endotracheal intubation by UK paramedics

OBJECTIVES

The recent introduction of a disposable laryngeal mask airway has provided paramedics with an alternative to endotracheal intubation. Time taken to secure the airway with each device was compared in patients undergoing elective surgery.

METHODS

Patients undergoing general anaesthesia were studied. Paramedics trained in laryngeal mask use and endotracheal intubation participated in the study. A Portex disposable laryngeal mask was inserted and removed, followed by a Portex endotracheal tube. Time taken from beginning of the procedure to ventilation of the patient was recorded.

RESULTS

Laryngeal mask insertion and endotracheal intubation was attempted on 52 patients. Median age was 63.5 years (range 39-83). Laryngeal mask insertion was successful in 88.5% (46 of 52) patients; endotracheal intubation was successful in 71.2% (37 of 52) patients (after no more than two attempts), p = 0.049. Intubation success was related to laryngoscopic view (87.5% grade 1, 56.3% grade 2, 0.0% grade 3. p<0.0001). When laryngeal mask/endotracheal tube insertion were both successful (n = 35 of 52), there was no significant difference in median time to secure the airway (laryngeal mask 47.0 seconds (range 24-126) compared with endotracheal tube 52.0 seconds (range 27-148) p = 0.22). Laryngeal mask insertion was successful in 80.0% (12 of 15) patients in whom endotracheal intubation had failed.

CONCLUSIONS

Even under optimal conditions, 30% of attempts at intubation by paramedics were unsuccessful. A disposable laryngeal mask has a higher success rate in securing the airway and overall, secures the airway more reliably than endotracheal intubation.