ProSeal versus Classic laryngeal mask airway (LMA) for positive pressure ventilation in adults undergoing elective surgery

Can Laryngeal Mask Airway be the First Choice for Tracheal Stenosis Surgery? A Historical Cohort Study

Objectives

To compare the usage of laryngeal mask airway (LMA) and orotracheal intubation (OTI), which are separate airway management methods in tracheal reconstruction surgeries, in terms of perioperative management, mortality, and morbidity.

Methods

Adult patients who underwent tracheal reconstruction surgery between June 2020 and June 2022 were included in the study, retrospectively. Patients with lost data or primary tracheal malignancy were excluded. Patients who underwent tracheal reconstruction were divided into two groups: LMA and OTI.

Results

Of a total of 57 included patients, the OTI and LMA groups had 30 (52.63%) and 27 patients (47.37%), respectively. The rate of intubated transfer to the intensive care unit and the length of stay in the intensive care unit were significantly higher in the OTI group (p=0. 014, p=0. 031) than those of the LMA group; further, in tracheal cultures, reproduction was also significantly higher in the OTI group (23.33%) (p=0. 007). The postoperative mortality rates were similar in both groups.

Conclusion

Since the absence of tension in end-to-end anastomosis of the trachea is vital for successful surgery, the LMA application (which has no tracheal contact) can be considered superior to OTI. In this study, LMA was successfully applied in all patients. Considering that the aim of anesthesia management should be to provide adequate oxygenation and normocarbia with minimally invasive intervention, we suggest airway management using LMA as the first option for tracheal reconstruction surgery because of the advantages described in this study.

Supraglottic airway devices: a powerful strategy in airway management

The escalating airway management demands of cancer patients have prompted us to continually curate airway devices, with supraglottic airway devices (SADs) playing a significant role in this regard. SADs serve as instrumental tools for maintaining an open upper airway. Since the inception of the earliest SADs in the early 1980s, an array of advanced and enhanced second-generation devices have been employed in clinical settings. These upgraded SADs integrate specific features designed to enhance positive-pressure ventilation and mitigate the risk of aspiration. Nowadays, they are extensively used in general anesthesia procedures and play a critical role in difficult airway management, pre-hospital care, and emergency medicine. In certain situations, SADs may be deemed a superior alternative to endotracheal tube (ETT) and can be employed in a broader spectrum of surgical and non-surgical cases. This review provides an overview of the current evidence, a summary of classifications, relevant application scenarios, and areas for improvement in the development or clinical application of future SADs.

Comparing leak pressure of LMA® ProSeal™ versus i-gel® at head rotation: a randomized controlled trial

PURPOSE

The effect of head rotation on supraglottic airway (SGA) oropharyngeal leak pressure (OPLP) has not been well elucidated. The aim of this study was to help clarify which SGA device provides higher OPLP at head-rotated position.

METHODS

Patients who underwent elective surgery under general anesthesia were enrolled and randomly divided into laryngeal mask airway (LMA®) ProSeal™ and i-gel® groups. The allocated SGA device was inserted under anesthesia. The primary outcome was OPLP, and secondary outcomes were ventilation score, expiratory tidal volume, and maximum pressure under volume-controlled ventilation (VCV) with an inspiratory tidal volume of 10 mL·kg-1 ideal body weight and fibreoptic view of the vocal cords at 0°, 30°, and 60° head rotation.

RESULTS

Data from 78 and 76 patients were analyzed in the LMA ProSeal and i-gel groups, respectively. The mean (standard deviation) OPLP of the LMA ProSeal was significantly higher than that of the i-gel at the 60° head-rotated position (LMA ProSeal, 20.4 [6.5] vs i-gel, 16.9 [7.8] cm H2O; difference in means, 3.6; adjusted 95% confidence interval, 0.5 to 6.6; adjusted P = 0.02, adjusted for six comparisons). The maximum pressure under VCV at 60° head rotation was significantly higher in the LMA ProSeal group than in the i-gel group. The expiratory tidal volume of the LMA ProSeal did not significantly change with head rotation and was significantly higher than that of the i-gel at 60° head rotation. Ventilation score, fibreoptic view of the vocal cords, and complications were not significantly different between the ProSeal and i-gel groups.

CONCLUSIONS

The LMA ProSeal provides higher OPLP than the i-gel at a 60° head-rotated position under general anesthesia.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (https://jrct.niph.go.jp) (JRCT1012210043); registered 18 October 2021.

Comparison of laryngeal mask airway and endotracheal tube in general anesthesia in children

At present, there is no relevant expert consensus indicating which ventilation device is more efficient for general anesthesia. The present literature review and meta-analysis compared the effects of the laryngeal mask airway and endotracheal intubation on airway complications during general anesthesia. The keywords 'laryngeal mask airway', 'endotracheal tube', 'tracheal tube', 'children', 'pediatric', 'anesthesia', 'randomized controlled trials' (RCTs) and 'randomized' were used to perform the literature search in PubMed. Quality assessment was performed by two reviewers according to domains defined by the Cochrane Collaboration tool. Data extraction, risk of bias assessment and quality of evidence assessment were performed with the Cochrane tool. A total of 16 RCTs were included. The results indicated that the effects of the laryngeal mask airway group on heart rate variability [mean difference=-13.76; 95% CI, -18.19-(-9.33); P<0.00001], the incidence of hypoxemia [odds ratio (OR)=0.52; 95% CI, 0.28-0.97; P=0.04] and the incidence of postoperative cough (OR=0.22; 95% CI, 0.12-0.40; P<0.0001) were significantly lower than those of the endotracheal intubation group. The success rate of one-time implantation in the laryngeal mask airway group was significantly higher than that noted in the endotracheal intubation group (OR=0.20; 95% CI, 0.07-0.59; P=0.003). However, no significant differences were noted between the two groups in bronchospasm, sore throat, mucosal injury, nausea and vomiting and reflux aspiration. In conclusion, the results indicated that laryngeal mask airway application can reduce complications during general anesthesia compared with endotracheal intubation.

Comparison of the Jcerity Endoscoper Airway with the LMA supreme for airway management in patients undergoing cerebral aneurysm embolization: a randomized controlled non-inferiority trial

BACKGROUND

Jcerity Endoscoper Airway is a new back-open endoscopic laryngeal mask airway device with a unique design. Our study sought to compare the implantation, ventilation quality and complications of JEA (Jcerity Endoscoper airway) versus LMA (Laryngeal Mask Airway) Supreme in the procedure of cerebral aneurysm embolization.

METHODS

In this prospective, randomised clinical trial, 182 adult patients with American Society of Anesthesiologists class Ι-II scheduled for interventional embolization of cerebral aneurysms were randomly allocated into the Jcerity Endoscoper airway group and the LMA Supreme group. We compared success rate of LMA implantation, ventilation quality, airway sealing pressure, peak airway pressure, degree of blood staining, postoperative oral hemorrhage, sore throat and other complications between the groups.

RESULTS

There were no significant differences between the groups in terms of one-time success rate of LMA implantation, ventilation quality, airway sealing pressure or airway peak pressure. However, LMA Supreme group showed a higher degree of blood staining than the JEA group when the laryngeal mask airway was removed (P = 0.04), and there were also more oral hemorrhages and pharyngeal pain than JEA group (P = 0.03, P = 0.02). No differences were observed between groups in terms of other airway complications related to the LMA.

CONCLUSIONS

The JEA could not only achieve comparable one-time success rate of implantation and quality of ventilation as the LMA Supreme, but also have lower blood staining degree of mask and less sore throat in patients undergoing perioperative anticoagulation for cerebral aneurysm interventional embolization.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100044133 ; Registered 11/03/2021. Statement: This study adheres to CONSORT guidelines.

Severe gastric insufflation and consequent atelectasis caused by gas leakage using AIR-Q laryngeal mask airway: A case report

BACKGROUND

The airways of patients undergoing awake craniotomy (AC) are considered “predicted difficult airways”, inclined to be managed with supraglottic airway devices (SADs) to lower the risk of coughing or gagging. However, the special requirements of AC in the head and neck position may deteriorate SADs’ seal performance, which increases the risks of ventilation failure, severe gastric insufflation, regurgitation, and aspiration.

CASE SUMMARY

A 41-year-old man scheduled for AC with the asleep–awake–asleep approach was anesthetized and ventilated with a size 3.5 AIR-Q intubating laryngeal mask airway (LMA). Air leak was noticed with adequate ventilation after head rotation for allowing scalp blockage. Twenty-five minutes later, the LMA was replaced by an endotracheal tube because of a change in the surgical plan. After surgery, the patient consistently showed low tidal volume and was diagnosed with gastric insufflation and atelectasis using computed tomography.

CONCLUSION

This case highlights head rotation may cause gas leakage, severe gastric insufflation, and consequent atelectasis during ventilation with an AIR-Q intubating laryngeal airway.

Is HFJV a better alternative ventilation technique for percutaneous dilatational tracheostomy? A randomised trial

BACKGROUND

High-Frequency Jet Ventilation (HFJV) has been used for the treatment of tracheal lesions, airway surgery, and treatment of secondary lesions after tracheostomy for many years however, reports on the use of HFJV during PDT are limited. This study compares the use of traditional method, ventilation with LMA, and HFJV through ETT with respect to the duration of PDT procedure and complications.

METHODS

Seventy-five patients were randomized into one of the three groups with computergenerated random numbers: Group ETT (n_25), group LMA (n=25), and group HFJV (n=25). Demographic data, duration of PDT, complications such as ETT cuff puncture and tube transaction, accidental extubation, difficult cannula insertion, bleeding, desaturation during the procedure, arterial blood gases immediately before and after the procedure have been recorded.

RESULTS

Mean time for successful PDT in group ETT was 5.9±1.35 minutes, in group LMA 4.96±0.78 minutes, and 3.88±0.78 minutes in group HFJV. PDT duration was shorter in the LMA group than in the ETT group (p<0.05). In the HFJV group, the PDT duration was shorter than the LMA group (p<0.05) and the ETT group (p<0.001). In terms of the total number of complications, significantly fewer complications were observed in the HFJV group compared with group ETT and group LMA.

CONCLUSIONS

HFJV may be a more effective alternative method for airway management during PDT, facilitating and reducing the duration of the intervention.

LMA® protector™ in patients undergoing laparoscopic surgeries: a multicenter prospective observational study

BACKGROUND

Laryngeal masks airway (LMA) has been increasingly used in surgical patients. However, the use of LMA in laparoscopic surgeries remains controversial. The major concerns include the potential risk of esophageal regurgitation, aspiration, and difficulties to achieve effective ventilation. The aim of this study was to evaluate the safety and effectiveness of the LMA® Protector™ in patients undergoing laparoscopic surgery.

METHODS

Patients aged 18 to 70 years, scheduled for laparoscopic surgeries were included. The insertion time, successful insertion rate, and oropharyngeal leak pressure were measured. Airway complications and airway manipulations during the procedure were documented. Effective ventilation rate was calculated. Visible bloodstains and reflux content in the drainage channel were documented after the removal of LMA® Protector™.

RESULTS

Three hundred patients were enrolled. The insertion of LMA® Protector™ failed in seven patients resulting with a successful insertion rate of 97.7%. During the maintenance of anesthesia, airway manipulation was required in 19 patients (19/293, 6.48%), in three of whom the LMA was replaced with endotracheal intubation resulting with an effective ventilation rate of 96.7% (290/300). The oropharyngeal leak pressure was 30.18 ± 5.88 cmH2O. Seventy-five patients (25.86%) reported mild sore throat on the first day after surgery. Bloodstains on study devices were noticed in 58 patients (20%). Seventy-five patients (25.86%) reported mild sore throat on the first day after surgery. Gastric reflux was noticed in the drainage tube in 5 patients (1.72%) with no signs of aspiration in any of those patients.

CONCLUSIONS

The LMA® Protector™ was shown to be safe and effective in patients undergoing laparoscopic surgeries. Although minor complications that require no further treatment, no clinically diagnosed aspiration was noticed in our study. Gastric reflux was noticed in the drainage tube in five patients undergoing laparoscopic gynecology surgery. Further research is needed to verify whether LMA® Protector™ is suitable for procedures in Trendelenburg position or other situations that a high risk of gastroesophageal reflux exists.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry ( ChiCTR1800018300 , date of registration: September 2018).

The effects of on hemodynamics, oxygen saturation, peak airway pressure and adverse events during anesthesia for thyroid surgery: tracheal intubation Vs. ProSeal laryngeal mask airway

OBJECTIVE

To investigate the effect of tracheal intubation and ProSeal laryngeal mask airway (PLMA) on hemodynamics, oxygen saturation, peak airway pressure and adverse events during anesthesia for thyroid surgery.

METHODS

65 patients who underwent luminal thyroid surgery under general anesthesia were enrolled as the study subjects, and were divided into control group (30 patients, tracheal intubation) and experimental group (35 patients, PLMA) using random number table. The time to establishment of artificial airway and success rate, hemodynamics, oxygen saturation, peak airway pressure and adverse effects were observed in the two groups.

RESULTS

The SBP, DBP, and HR levels of patients in the experimental group were significantly lower than those of control group (P < 0.05), and there were no significant changes in SBP, DBP, and HR levels during the insertion and removal of the laryngeal mask, and the patients were hemodynamically stable. SpO2 and Ppeak values remained stable at 5 min, 30 min, and 60 min after the start and the end of surgery in both groups, and showed no significant difference between the two groups (P > 0.05). A surgical airway was quickly established in both groups, and the time to airway establishment was shorter in the experimental group than in the control group. The incidence of adverse reactions during extubation was lower in the experimental group than in the control group, and the incidence of hoarseness, choking and cough differed significantly between the two groups (P < 0.05), and the adverse reactions in both groups were relieved or disappeared 24 h after the operation.

CONCLUSION

With LMPA, patients are more hemodynamically stable during insertion and removal of the mask, have a lower incidence of adverse events, and experience less throat irritation, with safety.

Choosing the best supraglottic airway for ophthalmic general anaesthesia: a manikin study

General anaesthesia is sometimes favoured over regional anaesthesia in ophthalmic surgery. The use of supraglottic airway (SGA) or laryngeal mask airway (LMA) as the primary airway device is increasing due to numerous advantages over tracheal intubation. Compared with 1st generation SGAs, 2nd generation SGAs have an added benefit of isolating the airway from the alimentary tract. However, the vertical profile of SGAs may encroach into the surgical field and hence interfere with surgery. We investigated the vertical projections of 1st generation SGAs (LMA Classic, Ambu AuraFlex) and commonly used 2nd generation SGAs in our institution (LMA ProSeal, LMA Supreme, LMA Protector, Ambu AuraGain and I-gel) in a manikin model. Each device was connected to a corrugated catheter mount or angled connector following insertion as per usual clinical practice in our institutions. Vertical projections of all devices were measured from the chin using a centimetre ruler. Securing of airway device to the chin with an adhesive tape was possible for the LMA Classic and Ambu AuraFlex with straight corrugated connector, whereas the stiffer 2nd generations SGAs required the addition of an angled connector or straight corrugated tubing to direct the airway tube caudally, away from the surgical field. The LMA ProSeal had the lowest vertical projection amongst the 2nd generation SGAs and may be the suitable choice for ophthalmic surgery. We also describe a novel technique of utilising a 1st generation SGA with placement of an orogastric tube, although with some reservations. This study has several limitations and transferability of our findings into clinical practice is questionable as the use of a manikin may not fully imitate the real condition of the patient. Our study is the first study comparing vertical projected height of different SGAs in manikin, but future studies should investigate the use of SGA in the clinical setting during ophthalmic surgery.

Laryngeal mask versus facemask in the respiratory management during catheter ablation

BACKGROUND

The purpose of this study is to investigate if a laryngeal mask could improve respiratory condition during radiofrequency catheter ablation (RFCA).

METHODS

Twenty-four consecutive patients who underwent RFCA for atrial fibrillation were divided into two groups (Facemask group; n = 10, Laryngeal mask group; n = 14). All patients were completely sedated under intravenous anesthesia and fitted with artificial respirators during the RFCA. The capnography waveforms and their differential coefficients were analyzed to evaluate the changes of end-tidal CO₂ (ETCO₂) values, respiratory intervals, expiratory durations, and inspiratory durations.

RESULTS

During the RFCA, ETCO₂ values of the laryngeal mask group were higher than those of the facemask group (36.0 vs. 29.2 mmHg, p = 0.005). The respiratory interval was significantly longer in the laryngeal mask group than those in the facemask group (4.28 s vs.5.25 s, p < 0.001). In both expiratory and inspiratory phases, the mean of the maximum and minimum values of CO₂ was significantly higher when using a laryngeal mask than when using a facemask. The inspiratory-expiratory ratio of the laryngeal mask group was significantly larger than that of the facemask group (1.59 vs. 1.27, p < 0.001). The total procedure duration, fluoroscopic duration and the ablation energy were significantly lower in the laryngeal mask group than in the facemask group. The ETCO₂ value is the most influential parameter on the fluoroscopic duration during the RFCA procedure (β = - 0.477, p = 0.029).

CONCLUSIONS

The use of a laryngeal mask could stabilize respiration during intravenous anesthesia, which could improve the efficiency of RFCA.

Gnana Laryngeal Airway in Clinical Practice: A Prospective Observational Study

Objective

The Gnana Laryngeal Airway (GLA) device, a novel supraglottic airway device, is similar to the LMA-Classic in basic design, but with an additional suction port on the convex portion of the laryngeal mask to remove the saliva. We evaluated the GLA device in terms of ease and time to insertion, the number of attempts, oropharyngeal leak pressure (OLP), correct placement, and complications in adult patients undergoing elective surgical procedures.

Methods

After general anaesthesia, the GLA device was inserted in ASA Class I–II consecutive patients aged 18–60 years, who were scheduled for elective surgeries lasting <2h. An independent observer noted (1) 10 consecutive successful GLA device insertions, all on the first attempt; (2) 10 consecutive device insertions, each <20 second in duration; and (3) 10 consecutive patients with the mean leak <10%. The criteria were fulfilled in 50 consecutive patients.

Results

In 72% of patients, the GLA device was successfully placed on the first attempt and was effortless in 64%. Between the first 10 and last 10 consecutive patients of the total 50, the ease-of-insertion grade progressively decreased (mean±standard deviation [SD]: 2.80±0.25 to 1.30±0.15, p<0.0001) and so did insertion time in seconds (28.70±1.87 to 14.20±0.79, p<0.0001). The post-insertion, OLP and airway compliance progressively increased, while the cuff inflation volume, peak airway pressure and airway resistance progressively decreased, along with minimal side effects and malposition.

Conclusion

The GLA device insertion became progressively easier and faster; thus, such a device is promising and warrants further clinical evaluation.

Comparison of standard versus 90° rotation technique for LMA Flexible™ insertion: a randomized controlled trial

Background

Insertion of a flexible laryngeal mask airway (LMA Flexible) is known to be more difficult than that of a conventional laryngeal mask airway. The 90° rotation technique can improve the success rate with a conventional laryngeal mask airway but its effect with the LMA Flexible remains unknown. We assessed whether the 90° rotation technique increased the first-attempt success rate of LMA Flexible insertion versus the standard technique.

Methods

In total, 129 female patients undergoing breast surgery were analyzed. The primary endpoint was success at the first attempt. The insertion time, number of trials, number of manipulations required, and oropharyngeal leak pressure were also evaluated. Heart rate and mean blood pressure were recorded 1 min before and 1 min after insertion. Blood staining on the LMA Flexible after removal and postoperative sore throat were checked.

Results

The first-attempt success rates were comparable between the groups (93% vs. 98.3%, P = .20). The insertion time, number of trials and manipulations, hemodynamic variables, and complications, such as blood staining and sore throat, did not differ between the groups.

Conclusions

The 90° rotation technique is a good alternative to the standard technique for insertion of the LMA Flexible.

Trial registration

ClinicalTrials.gov (NCT03028896). It was registered retrospectively at Jan 19th, 2017.

Getting it right first time: time to simplify our approach to the airway by using our best tools first

Deciding on the techniques and equipment to use when managing a patient’s airway during anaesthesia is a complex process. It is influenced by many factors, including the type of surgery being undertaken, patient co-morbidities, perceived risk of airway difficulty or pulmonary aspiration and the availability of more advanced equipment. While there are many guidelines for management of the unanticipated difficult airway, there are few if any for routine airway management. It is likely that current practices are heavily influenced by national and institutional norms, personal experiences and preferences of the individual anaesthetist involved.

Laryngeal mask airway versus endotracheal tube for percutaneous dilatational tracheostomy in critically ill adults

BACKGROUND

Percutaneous dilatational tracheostomy (PDT) is one of the most common bedside surgical procedures performed in critically ill adults, on intensive care units (ICUs), who require long-term ventilation. PDT is associated with relevant life-threatening complications: Cuff rupture or accidental extubation may lead to hypoxia, aspiration or loss of airway. Puncture of the oesophagus, or creating a false passage during dilatation or replacement of the tracheostomy tube, can lead to pneumothorax or emphysema. Wound infections may occur which can cause mediastinits, especially after creation of false passage or in early tracheotomized post-sternotomy patients after cardiac surgery. During the procedure, the patient's airway can be secured with an endotracheal tube (ETT) or a laryngeal mask airway (LMA). This is an updated version of the review first published in 2014.

OBJECTIVES

To assess the safety and effectiveness of LMA versus ETT in critically ill adults undergoing PDT on the ICU.

SEARCH METHODS

We searched the following databases to 9 January 2018: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase. We searched for reports of ongoing trials in the metaRegister of Controlled Trials (mRCT). We handsearched for relevant studies in conference proceedings of five relevant annual congresses. We contacted study authors and experts concerning unpublished data and ongoing trials. We searched for further relevant studies in the reference lists of all included trials and of relevant systematic reviews.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared use of laryngeal mask airways versus endotracheal tubes in critically ill adults undergoing elective PDT in the ICU, without injuries to or diseases of the face or neck. We imposed no restrictions with regard to language, timing or technique of PDT performed.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of each study and carried out data extraction. Our primary outcomes were all-cause mortality, procedure-related mortality and tally of participants with one or more serious adverse events. Where possible, we combined homogeneous studies for meta-analysis. We used Cochrane's 'Risk of bias' tool and used GRADE to assess the quality of evidence for key outcomes.

MAIN RESULTS

We included nine RCTs in this review involving 517 participants.Studies had a high or unclear risk of bias. The main reason for this was low methodological quality or missing data, even after study authors were contacted. Study size was generally small, with a minimum of 40, and a maximum of 73 participants.In one study (40 participants), three deaths in the LMA group and two deaths in the ETT group were reported, although none of the deaths were related to the procedure (very low-quality evidence).Five studies (281 participants) reported on procedure-related deaths, stating that no procedure-related death occurred at all (very low-quality evidence).It is uncertain whether there is a difference in the number of people experiencing one or more serious adverse event(s) between LMA and ETT (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.41 to 1.80; 467 participants, 8 studies, very low-quality evidence).The duration of the procedure may be shorter in the LMA group (mean difference (MD) -1.46 minutes, 95% CI -1.92 to -1.01 minutes; 6 studies, 324 participants, low-quality evidence).However failure of procedure, as allocated by randomization, requiring conversion to any other procedure, may be higher in the LMA group (RR 2.82, 95% CI 1.22 to 6.52; 8 studies, 439 participants, low-quality evidence).We did not find any clear evidence of a difference between ETT and LMA groups for all other outcomes. Only one study provided follow-up data for late complications related to the intervention, showing no clear evidence of benefit for any treatment group.

AUTHORS' CONCLUSIONS

Evidence on the safety of LMA for PDT is too limited to allow conclusions to be drawn on either its efficacy or safety compared with ETT. Although the LMA procedure may shorten the period during which the airway is insecure, it may also lead to higher conversion rates. Also, late complications have not been investigated sufficiently. These results are primarily based on single-centre trials with small sample sizes, and therefore the level of evidence remains low. Studies with low risk of bias focusing on late complications and relevant patient-related outcomes are necessary for definitive conclusions on safety issues related to this procedure. The dependency of the successful placement of a LMA on the type of LMA used should also be further assessed.There are two studies awaiting classification that may alter the conclusions once assessed.

ProSeal versus Classic laryngeal mask airway (LMA) for positive pressure ventilation in adults undergoing elective surgery

BACKGROUND

The development of supraglottic airway devices has revolutionized airway management during general anaesthesia. Two devices are widely used in clinical practice to facilitate positive pressure ventilation: the ProSeal laryngeal mask airway (pLMA) and the Classic laryngeal mask airway (cLMA). It is not clear whether these devices have important clinical differences in terms of efficacy or complications.

OBJECTIVES

To compare the effectiveness of the ProSeal laryngeal mask airway (pLMA) and the Classic LMA (cLMA) for positive pressure ventilation in adults undergoing elective surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 3) in the Cochrane Library; MEDLINE (Ovid SP, 1997 to April 2017); Embase (Ovid SP, 1997 to April 2017); the Institute for Scientific Information (ISI) Web of Science (1946 to April 2017); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO host, 1982 to April 2017).We searched trial registries for ongoing studies to April 2017.We did not impose language restrictions. We restricted our search to the time from 1997 to April 2017 because pLMA was introduced into clinical practice in the year 2000.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared the effectiveness of pLMA and cLMA for positive pressure ventilation in adults undergoing elective surgery. We planned to include only data related to the first phase of cross-over RCTs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane Collaboration.

MAIN RESULTS

We included eight RCTs that involved a total of 829 participants (416 and 413 participants in the pLMA and cLMA groups, respectively). We identified six cross-over studies that are awaiting classification; one is completed but has not been published, and data related to the first treatment period for the other five studies were not yet available. Seven included studies provided data related to the primary outcome, and eight studies provided data related to more than one secondary outcome.Our analysis was hampered by the fact that a large proportion of the included studies reported no events in either study arm. No studies reported significant differences between devices in relation to the primary review outcome: failure to adequately mechanically ventilate. We evaluated this outcome by assessing two variables: inadequate oxygenation (risk ratio (RR) 0.75, 95% confidence interval (CI) 0.17 to 3.31; four studies, N = 617) and inadequate ventilation (not estimable; one study, N = 80).More time was required to establish an effective airway using pLMA (mean difference (MD) 10.12 seconds, 95% CI 5.04 to 15.21; P < 0.0001; I² = 73%; two studies, N = 434). Peak airway pressure during positive pressure ventilation was lower in cLMA participants (MD 0.84, 95% CI 0.02 to 1.67; P = 0.04; I² = 0%; four studies, N = 259). Mean oropharyngeal leak (OPL) pressure was higher in pLMA participants (MD 6.93, 95% CI 4.23 to 9.62; P < 0.00001; I² = 87%; six studies, N = 709).The quality of evidence for all outcomes, as assessed by GRADE score, is low mainly owing to issues related to blinding and imprecision.Data show no important differences between devices with regard to failure to insert the device, use of an alternate device, mucosal injury, sore throat, bronchospasm, gastric insufflation, regurgitation, coughing, and excessive leak. Data were insufficient to allow estimation of differences for obstruction related to the device. None of the studies reported postoperative nausea and vomiting as an outcome.

AUTHORS' CONCLUSIONS

We are uncertain about the effects of either of the airway devices in terms of failure of oxygenation or ventilation because there were very few events. Results were uncertain in terms of differences for several complications. Low-quality evidence suggests that the ProSeal laryngeal mask airway makes a better seal and therefore may be more suitable than the Classic laryngeal mask airway for positive pressure ventilation. The Classic laryngeal mask airway may be quicker to insert, but this is unlikely to be clinically meaningful.