Classic Laryngeal Mask Airway Research Articles

Laryngeal mask airway for transsternal thymectomy in myasthenic patients.

Sir, We read with interest the excellent article, ‘Use of ProSeal® laryngeal mask airway (LMA) and thoracic epidural in myasthenia patients for transsternal thymectomy: A case series’ by Simon et al.[1] We are pleased that our case series on LMA use for transsternal thymectomy in patients with myasthenia gravis was cited.[2] We want to draw attention to one point discussed in the article.[1] The authors mention that ‘ProSeal® LMA’ has major advantage over the classic LMA and state, referring to our publication, that ‘…there are similar successful case reports using ProSeal® LMA, but our technique remains unique….’ However, our case series consisted of use of classic LMA for transsternal thymectomy in patients with myasthenia gravis. The authors mention the disadvantages of the classic LMA use for transsternal thymectomy in patients with myasthenia gravis, then mention the advantages of ProSeal® LMA, citing our article,[2] and said that these results support the superiority of the authors' novel technique. This appears to be a misinterpretation of what we attempted to convey through our article because we used only classic LMA in our patients.[2] The use of LMA causes less airway resistance than the endotracheal intubation which can, in turn lead to decreased pulmonary complications such as lesser incidence of atelectasis, less risk of pulmonary infections and reduced bronchoconstrictive reflex.[3] The use of LMA also causes fewer bouts of coughing and exerts a lesser effect on mucociliary activity than the endotracheal intubation.[4,5] The major advantage of the use of LMA for airway control is that no muscle relaxant is needed in myasthenic patients.[6] We think that the use of LMA (classic LMA or ProSeal® LMA) is a good alternative for transsternal thymectomy with total intravenous anaesthesia in myasthenic patients when compared to endotracheal intubation.

Comparison between nalbuphine propofol and dexmedetomidine propofol for laryngeal mask airway insertion

Aims and Objectives: The aim of the present study was to compare the laryngeal mask airway (LMA) insertion conditions using either nalbuphine - propofol or dexmedetomidine - propofol. Materials and Methods: Sixty female patients aged 25–35 years posted for interval tubal ligation were randomly allocated in two groups of 30 each. Group N received intravenous injection nalbuphine 0.2 mg/kg over 5 min, and Group D received injection dexmedetomidine 1 μg/kg over 5 min. Later, all the patients were induced with injection propofol 2 mg/kg and 90 s after induction, classic LMA of number 3 was inserted in all the patients. LMA insertion conditions were assessed using various parameters. Heart rate, mean arterial pressure, respiratory rate, and SpO2were recorded before induction and at 1, 3, 5, and 10 min after LMA insertion. Incidence and duration of apnea were also recorded. Observations and Results: Demographic data were comparable in both the groups. LMA insertion conditions were comparable in both the groups (P = 0.15), and both the groups had excellent LMA insertion conditions. The apnea duration was slightly more in dexmedetomidine group (140 s) as against nalbuphine group (120 s). The reduction in heart rate was more in Group D and the difference was statistically significant at 1 and 3 min after induction (P < 0.001). Conclusion: Nalbuphine combined with propofol provides similar conditions of LMA insertion as that of dexmedetomidine - propofol combination with advantage of better maintenance of hemodynamic stability.

A prospective, randomized comparative study for use of proseal laryngeal mask airway as an alternative to endotracheal intubation for airway management in children under general anesthesia

Introduction: Proseal laryngeal mask airway (PLMA) which is an upgraded modification of classic LMA, incorporating a gastric drainage tube lateral to the main airway tube which permits the regurgitated liquid gastric contents to bypass the glottis and prevents pulmonary aspiration. A prospective randomized interventional comparative study was performed to compare the efficiency of PLMA with a tracheal tube (TT) in pediatric patients with respect to number of attempts to placement of devices, hemodynamic responses and perioperative complications. Material and Methods: Sixty children, ASA physical status I and II weighing 10-20 kg between 2 and 8 years of age group of either sex undergoing elective infraumblical surgeries of 30-60 minutes duration, randomly divided into two group of 30 patients each. All patients were premedicated with IV midazolam and glycopyrrolate. General anesthesia with caudal epidural analgesia was given in all cases. IV propofal and sevoflurane was used for inducing general anesthesia. PLMA was inserted in group I and tracheal tube (TT) in patients of group II. In all cases after PLMA / TT insertion; caudal epidural analgesia was given and general anesthesia (GA) was maintained with O2, N2O and sevoflurane. Results: Ease of insertion was comparable in both the groups. There were no significant differences in mean oxygen saturation SpO2 (%) and end tidal carbon dioxide (ETCO2)) levels recorded at different time intervals between the two groups. However, highly significant changes in hemodynamic parameters were observed in the TT group. Complications such as nausea and vomiting (3.33%), sore throat (2%) and coughing (26.66%) were observed in the TT group. Conclusion: We concluded that PLMA could be used as an effective and safe airway device in children alternative to TT undergoing general anesthesia. Keywords: General anesthesia, Hemodynamic response, Paediatric, Proseal laryngeal mask airway, Tracheal tube

Application of Minimum Effective Cuff Inflating Volume for Laryngeal Mask Airway and its Impact on Postoperative Pharyngeal Complications.

Background:High intracuff pressure can cause severe pharyngeal complications including sore throat or hoarseness after laryngeal mask airway (LMA) removal postoperatively. Though the application of minimum effective cuff inflating volume is suggested to maintain airway sealing and adequacy of ventilation for patients receiving general anesthesia with LMA at lower level of the intracuff pressure, it is currently not a standard care in most of the anesthetic departments. In this study, the minimum effective cuff inflating volume was determined for classic LMA Well Lead™ (Well Lead Medical Co., Ltd., China) and its impact on postoperative pharyngeal complications was also explored.Methods:Patients with American Society of Anesthesiologists physical status (I–III) undergoing the short-duration urological surgery were recruited in this trial. First, the minimum effective cuff inflating volume was determined for size 4 or 5 LMA Well LeadTM in the study 1. Immediately following placement and confirmation of ideal LMA position, the cuff was inflated with 5, 7, 10 ml of air and up to 30 ml at 5 ml increment. The intracuff pressure, oropharyngeal leak pressure (OLP), and inspiratory peak airway pressure under positive pressure ventilation at the corresponding cuff volume as indicated above were recorded. Second, the enrolled patients were randomly allocated into minimum effective cuff inflating volume group (MC) and routine care (RC) group in the study 2. The minimum effective cuff inflating volume was applied and maintained in MC group, whereas the cuff volume was inflated with half of the maximum cuff inflating volume recommended by manufacturer in RC group throughout the surgical procedure and stay in postanesthesia care unit prior to LMA removal. The incidence of pharyngeal complications at 0, 2, 24, and 48 h after removal of LMA and other intra-operative adverse events were also documented.Results:The intracuff pressure varied with the cuff inflating volume in a positive linear correlation manner (Y = 11.68X − 42.1, r2 = 0.9191) under the range of 5–30 ml for size 4 LMA. In similar with size 4 LMA, the data were also showed the linear relationship between the intracuff pressure and the cuff inflating volume (Y = 7.39X − 10.9, r2 = 0.8855) for size 5 LMA. The minimal effective cuff inflating volume for size 4 or 5 LMA was 7–9 ml in combination of considering OLP needed to maintain airway sealing during intermittently positive pressure ventilation. The intracuff pressure in MC group was lower compared with RC group (63.0 ± 3.7 vs. 126.4 ± 24.0 cmH2O for size 4 LMA; 55.6 ± 2.4 vs. 138.5± 26.8 cmH2O for size 5 LMA; P < 0.0001). The incidence of pharyngeal adverse events was lower in MC group versus the RC group at 2, 24 h after LMA removal.Conclusions:The relationship between the cuff inflating volume and the intracuff pressure for size 4 or 5 LMA Well Lead™ is in a linear correlation manner at the range of 5–30 ml. The minimal cuff inflating volume is adequate for satisfactory airway sealing and consequently associated with lower incidence of postoperative pharyngeal complications for LMA Well Lead.™

Laryngeal clefts

Laryngeal clefts

Comparison of I-gel with Classic Laryngeal Mask Airway Regarding the Ease of Use and Clinical Performance.

I-gel is a new supraglottic airway device without an inflatable cuff. We aimed to compare I-gel and the classic laryngeal mask airway (LMA) regarding the ease of use and clinical performance in Turkish population. Fifty American Society of Anesthesiologists (ASA) I-II patients were randomly allocated into two groups: Group I-gel and Group LMA. Insertion time and success in first attempt were recorded. Peak, plato and mean airway pressures, EtCO2, airway compliance and leak volume were periodically recorded during the operation. The presence of blood on device removal and postoperative sore throat were also assessed. The device insertion time in Group I-gel was shorter than that in Group LMA (21.00±4.15 vs. 30.40±12.17 s, p=0.001). The success rate in first attempt, peak, plato and mean airway pressures, EtCO2 and airway compliance did not differ between the groups. The leak volume was lower in Group I-gel 5 and 45 min after insertion (p=0.041 and p=0.027). The presence of blood on device removal and postoperative sore throat were similar in both groups. I-gel may be a more advantageous supraglottic airway device compared with LMA.

Comparison of Four Different Supraglottic Airway Devices in Terms of Efficacy, Intra-ocular Pressure and Haemodynamic Parameters in Children Undergoing Ophthalmic Surgery.

The aim of this study was to compare insertion parameters of four different types of supraglottic airway devices (SGAD) (Classic LMA, I-gel LMA, Proseal LMA, Cobra PLA) in children undergoing ophthalmic surgery and to determine the effect on intra-ocular pressure (IOP) and haemodynamic responses during insertion. Sixty American society of Anesthesiologists (ASA) I-II children aged 1-10 years undergoing extra-ocular ophthalmic surgery were randomly divided into four groups (Group LMA, Group I-gel LMA, Group PLMA and Group CPLA) in this prospective, randomised study. Anaesthesia was induced with decreasing sevoflurane concentrations (8%-2%) in a mixture of 50% N2O-O2. All SGADs were inserted under deep anaesthesia. The characteristics of insertion (number of attempts, ease and time), oropharyngeal leak pressure (OLP) and complications were recorded. IOP in both eyes, heart rate (HR), mean arterial pressure (MAP) and EtCO2 were measured before and 2 and 5 min after insertion of the SGADs. There was no difference between the groups in terms of the characteristics of insertion. The mean IOP did not increase significantly in all groups. MAP and HR changes were similar among the groups during follow-up. In all groups, HR increased 2 min after insertion (statistically insignificant) and returned to the baseline value 5 min after insertion. A statistically significant correlation was seen between HR increase and IOP values before and after insertion of the SGADs (p=0.006, correlation coefficient=0.352). Desaturation was seen in one patient in Groups LMA, PLMA and CPLA, and laryngospasm was seen in two patients in Group CPLA and in one patient in Group LMA. It was seen that during insertion of Classic LMA, I-gel LMA, Proseal LMA and Cobra PLA, IOP did not increase and haemodynamic stability was maintained in children undergoing extra-ocular ophthalmic surgery.

Better Hemodynamic Profile of Laryngeal Mask Airway Insertion Compared to Laryngoscopy and Tracheal Intubation.

Background:Laryngoscopy and tracheal intubation can cause serious cardiovascular responses in patients such as hypertension, tachycardia, and arrhythmias. Alternative airway maintenance techniques may attenuate these hemodynamic stress responses.Objectives:This study aimed to compare the immediate hemodynamic effects of the insertion of laryngeal mask airway supreme (LMA-S) and classic (LMA-C) with laryngoscopy and Endotracheal Intubation (ETT).Patients and Methods:This study was a prospective, double-blind, and randomized clinical trial conducted on 150 patients aged 18 to 50 years with ASA I (American Society of Anesthesiologists), in the general operating room of Shahid Mohammadi hospital, Hormozgan university of medical sciences, Bandar Abbas, Iran. In the ETT group, endotracheal intubation was performed using the Macintosh laryngoscope; while for the LMA-C and LMA-S groups, LMA Classic and LMA Supreme were inserted, respectively. The induction and maintenance of anesthesia were similar in all patients. The hemodynamic parameters such as heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured before (baseline) and after induction of anesthesia at 4 different time points. The statistical analysis was done and P value less than 0.05 was considered significant.Results:Participants in all groups were similar in terms of gender, age, weight, height, and Mallampati class. The mean ± SD of SBPs (105.62 ± 12.12, 112.90 ± 12.2, and 112.48 ± 15.14 mm Hg, respectively for ETT, LMA-C, and LMA-S) and DBPs (64.64 ± 10.23, 73.78 ± 9.70, and 71.20 ± 12.27 mm Hg, respectively for ETT, LMA-C, and LMA-S) were significantly lower in the ETT group compared to LMA groups 5 minutes after device insertion (P < 0.01 for SBPs and P < 0.001 for DBPs); however these values were lower than the baseline values in all groups. There were no differences in the mean SBP and DBPs between the three groups at the other time points. The mean ± SD heart rates in the ETT group, compared to the LMA-C and LMA-S groups, were considerably higher in the first minute (100.06 ± 18.27, 82.50 ± 10.52, and 82.00 ± 13.60 bpm, respectively for ETT, LMA-C, and LMA-S), third minute (91.04 ± 17.12, 78.84 ± 11.23, and 78.90 ± 13.41 bpm, respectively for ETT, LMA-C, and LMA-S) and fifth minute (85.82 ± 16.01, 75.78 ± 11.73, and 75.04 ± 13.90 bpm, respectively for ETT, LMA-C, and LMA-S) after intubation (P < 0.001). There were no significant differences between the LMA-C and LMA-S groups in terms of hemodynamic parameters.Conclusions:Maintaining the airway using laryngeal mask airway is associated with less cardiovascular responses compared to direct laryngoscopy and tracheal intubation.

Optimum sevoflurane concentration for I-gel insertion in unpremedicated children

Study objectiveEnd-tidal concentration of sevoflurane for I-gel insertion in children has not been studied. This study was designed to determine the sevoflurane EC50 and EC95 for I-gel placement in children as compared with classic laryngeal mask airway (CLMA) placement. DesignThe design was a prospective, randomized controlled study. SettingsThe setting was single tertiary care center. PatientsPediatric subjects of either sex aged 1.5-8 years, weighing 10-20 kg having American Society of Anesthesiologists physical status I/II of undergoing elective cataract surgery were included in the study. InterventionInduction and maintenance of anesthesia were achieved with sevoflurane and oxygen with preservation of spontaneous breathing. Children were randomly subjected to either I-gel size 2 (group I) or CLMA size 2 (group II) insertion. The target end-tidal sevoflurane concentration (ET SEVO) was maintained for 8-10 minutes before supraglottic airway device was inserted in both the groups. In the first child, the ET SEVO was kept at 2% and was increased or decreased by 0.2% in the next child depending on the previous child's response according to Dixon method. After each supraglottic airway device insertion, child was observed for 1 minute for any “movement” or “no movement.” MeasurementsThe measurements were EC50 and EC95 for I-gel and CLMA placement in children. Main resultsEC50 and EC95 for group I were 0.94% (0.83%-1.06%) and 1.26% (1.12%-1.66%) and for group II were 1.9% (1.70%-2.1%) and 2.54% (2.24%-3.41%), respectively. ConclusionI-gel insertion in children can be accomplished at nearly half ET SEVO (0.94%) of that required for CLMA insertion (1.9%).

I-Gel and Classic LMA - a Comparitive Study in Anaesthetized and Paralyzed Patients

I-Gel and Classic LMA - a Comparitive Study in Anaesthetized and Paralyzed Patients

Comparison of the Supraglottic Airway Devices Classic, Fastrach and Supreme Laryngeal Mask Airway: A Prospective Randomised Clinical Trial of Efficacy, Safety and Complications.

This prospective randomised study was designed to compare the Laryngeal Mask Airway (LMA) Classic, LMA Fastrach and LMA Supreme regarding ease of insertion and insertion time as primary outcomes and reposition, success rate of trials, effects on haemodynamic parameters, provision of an adequate and safe airway, amount of leakage and oropharyngeal and systemic complications as secondary outcomes. In this clinical trial, 90 patients aged 18-70 years of American Society of Anesthesiologists (ASA) group I-II were randomised into three groups as providing airway via LMA Classic, LMA Fastrach or LMA Supreme instead of tracheal intubation. No muscle relaxant was used. The allocated LMA was inserted by the same anaesthetist; bispectral index (BIS) was between 40% and 60%. There was no statistical difference among the groups regarding the ease of insertion and insertion time as primary outcomes; the incidence of repositioning during placement was significantly higher in the LMA Classic group than that in other groups (p<0.05) and the rates of bloodstain on the device as well as oropharyngeal mucosal oedema were higher in the LMA Fastrach group than those in other groups (p<0.05) as secondary outcomes. We suggest that LMA Classic, LMA Supreme and LMA Fastrach had similar effectiveness regarding efficiency and airway safety. However, LMA Supreme seems to be more advantageous as it is more appropriate for fewer oropharyngeal complications and there was no repositioning.

Does the self-pressurizing Air Q produce less postoperative sore throat compared with the classic laryngeal mask airway? A randomized controlled double-blind study

Background The aim of the study was to evaluate the risk for postoperative sore throat (POST) using the self-pressurizing Air Q compared with that using classic laryngeal mask airway (LMA). Patients and methods A total of 150 patients were included in this double-blind prospective study. After induction of general anesthesia, the airway was maintained with an Air Q device (in group Q, 75 patients) and with a classic LMA (in group C, 75 patients). The POST was evaluated and graded (on the basis of its severity) within 20 min in the recovery room and 24 h after surgery. Results The incidence of POST and its severity were comparable in both groups. Conclusion Despite the self-pressurizing cuff of Air Q, there was no reduction in the POST incidence or severity compared with that using classic LMA.

A comparison of I-gel with the LMA-classic in spontaneously breathing patients

Introduction Laryngeal mask airway (LMA) is a supraglottic airway device (SAD), which was primarily designed to facilitate airway maintenance. Thereafter, many modifications have been made in the SADs, and I-gel is a recent one, which has a unique characteristic of a self-inflatable cuff. It is claimed to be better in terms of ease and success of insertion, risk of complications, etc. Aims and objectives The aim of this study was to investigate and compare the insertion characteristics and complication rate of classic LMA with I-gel. Materials and methods Eighty patients of American Society of Anaesthesiologists I/II, between 16 and 60 years of age, of either sex were randomly divided into two groups of 40 patients each. In respective groups, classic LMA or I-gel were introduced under spontaneous ventilation. Insertion characteristics such as number of attempts at insertion, ease of insertion, better seal, etc. were studied. Proper positioning was confirmed as per fiberoptic view of the glottis. Patients were continuously monitored and hemodynamic variables were studied at frequent intervals. We also recorded the complications at the time of extubation, if any. Data were statistically analyzed using t -test and the χ 2 -test. A P value less than 0.05 was considered statistically significant. Results I-gel required less time to insertion (29.32 ± 6.88) compared with cLMA (36.72 ± 7.33 s) ( P 2 O) compared with the LMA group (20.77 ± 8.20 cm H 2 O) ( P = 0.003). Statistically significant difference was found between the two groups as regards the assessment of patients after removal of the SAD. Fiberoptic view of vocal cords was better in the I-gel group. Conclusion Insertion of I-gel was easier and quicker and proper positioning was achieved in more number of patients as compared with classic LMA. Moreover, there were fewer complications noted at the time of removal of the device.

Comparison of effects of classic LMA, cobraPLA and V-gel rabbit on QTc interval.

We aimed to compare the effects of three different supraglottic airway devices, the classic LMA, PLA, and V-gel, on hemodynamics and QTc in rabbits under general anesthesia. The rabbits were divided into four groups: Group C (n=5) control group with no airway device used, Group L (n=5, classic LMA), Group P (n=5, CobraPLA) and Group V (n=5, V-gel-rabbit). Basal values of heart rate (HR), mean arterial pressure (MAP) and ECG for QTc interval were measured and the measurements were evaluated at 1, 5, 15, and 30 minutes after inserting the airway device The values of HR, MAP and QTc in Group V at minutes 1 and 5 were significantly different to those in Group L and Group P (p<0.05). The classic-LMA and cobraPLA cover a wide part of the perilaryngeal area with cuffs inflated to about 60 cmH2O of pressure resulting in mucosal compression. As V-gel rabbit does not have a cuff, it covers a smaller part of the laryngopharyngeal area, and thus does not cause mucosal compression, and the hemodynamic response is weaker. When comparing hemodynamic responses to other supraglottic airway devices, the response to V-gel rabbit is minimal and we consider that similar studies using the I-gel on humans are required (Fig. 5, Ref. 31).

Use of ProSeal(®) LMA and thoracic epidural in myasthenia patients for trans-sternal thymectomy: A case series.

Myasthenia gravis is an autoimmune disease, resulting from the production of antibodies against the acetylcholine receptors of the neuromuscular endplate. Muscular weakness and fatigability are the hallmarks of myasthenia gravis. Myasthenic patients are sensitive to non-depolarising relaxants and post-operative ventilatory support may be required in high-risk patients. This can be attributed partly to endotracheal intubation and use of intermediate or long-acting muscle relaxants in such cases. The rate of post-operative ventilation after a trans-sternal thymectomy has been reported to be more than 50% in myasthenia gravis patients.[1] Two techniques have been recommended for general anaesthesia in the myasthenic patient. Due to the unpredictable response to succinylcholine and the marked sensitivity to non-depolarising muscle relaxants, some anaesthesiologists avoid muscle relaxants and depend on deep inhalational anaesthesia for tracheal intubation and maintenance of anaesthesia.[2,3] However, others utilise a balanced technique which includes the use of muscle relaxants, without the need for deep inhalational anaesthesia with its concomitant respiratory and cardiovascular side effects, provided neuromuscular transmission is monitored. In this paper, we would like to describe a new and successful technique of using ProSeal® laryngeal mask airway (LMA) with thoracic epidural for three cases who underwent trans-sternal thymectomy. We avoided muscle relaxant during the entire course of surgery and none of our cases required post-operative ventilation.

Randomized Comparison of Actual and Ideal Body Weight for Size Selection of the Laryngeal Mask Airway Classic in Overweight Patients.

Size selection of the laryngeal mask airway (LMA) Classic based on actual body weight remains a common practice. However, ideal body weight might allow for a better size selection in obese patients. The purpose of our study was to compare the utility of ideal body weight and actual body weight when choosing the appropriate size of the LMA Classic by a randomized clinical trial. One hundred patients with age 20 to 70 yr, body mass index ≥25 kg/m(2), and the difference between LMA sizes based on actual weight and ideal weight were allocated to insert the LMA Classic using either actual body weight or ideal body weight in a weight-based formula for size selection. After insertion of the device, several variables including insertion parameters, sealing function, fiberoptic imaging, and complications were investigated. The insertion success rate at the first attempt was lower in the actual weight group (82%) than in the ideal weight group (96%), even it did not show significant difference. The ideal weight group had significantly shorter insertion time and easier placement. However, fiberoptic views were significantly better in the actual weight group. Intraoperative complications, sore throat in the recovery room, and dysphonia at postoperative 24 hr occurred significantly less often in the ideal weight group than in the actual weight group. It is suggested that the ideal body weight may be beneficial to the size selection of the LMA Classic in overweight patients (Clinical Trial Registry, NCT 01843270).

Meteorological time series forecasting with pruned multi-layer perceptron and two-stage Levenberg-Marquardt method

A multi-layer perceptron (MLP) defines a family of artificial neural networks often used in TS modelling and forecasting. Because of its 'black box' aspect, many researchers refuse to use it. Moreover, the optimisation (often based on the exhaustive approach where 'all' configurations are tested) and learning phases of this artificial intelligence tool (often based on the Levenberg-Marquardt algorithm - LMA) are weaknesses of this approach (exhaustively and local minima). These two tasks must be repeated depending on the knowledge of each new problem studied, making the process, long, laborious and not systematically robust. In this paper, a pruning process is proposed. This method allows, during the training phase, to carry out an inputs selecting method activating (or not) inter-nodes connections in order to verify if forecasting is improved. We propose to use iteratively the popular damped least-squares method to activate inputs and neurons. A first pass is applied to 10% of the learning sample to determine weights significantly different from 0 and delete other. Then, a classical batch process based on LMA is used with the new MLP. The validation is done using 25 measured meteorological TS and cross-comparing the prediction results of the classical LMA and the two-stage LMA.

Comparação da máscara laríngea i‐gel (i‐gel™) com a máscara laríngea clássica (LMA‐Classic™) em relação ao desempenho clínico

PurposeThe i‐gel™ is one of the second generation supraglottic airway devices. Our study was designed to compare the i‐gel and the Laryngeal Mask Airway Classic™ with respect to the clinical performance. MethodsWe compared the performance of the i‐gel with that of the Laryngeal Mask Airway Classic in 120 patients undergoing urologic surgery during general anesthesia without muscle relaxant with respect to the number of attempts for successful insertion, insertion time, peak airway pressure, incidence of regurgitation, fiberoptic glottic view and postoperative complications. Second generation supraglottic airway devices were inserted by the same anesthesiologist, experienced in use of both devices (>200 uses and first time failure rate <5%). Methylene blue method was used to detect gastric regurgitation. ResultsThere was no statistical difference between the two groups regarding the success of insertion of second generation supraglottic airway device (p=0.951). The laryngeal mask insertion time for the i‐gel group was significantly shorter than that for the Laryngeal Mask Airway Classic group (11.6±2.4s versus 13.1±1.8s [p=0.001]). The fiberoptic glottic view scores for the i‐gel group was significantly better than that for the ones for the Laryngeal Mask Airway Classic group (p=0.001). On fiberoptic view, there was no sign of methylene blue dye at any time point in either group. In addition, there was no difference between the groups in patient response regarding the presence of a sore throat when questioned 24h after the procedure (p=0.752). ConclusionBoth devices had good performance with low postoperative complications and without occurrence of regurgitation. The i‐gel provided a shorter insertion time and a better fiberoptic view than the Laryngeal Mask Airway Classic.

Optimal size selection of the classic laryngeal mask airway by tongue width-based method in male adults

BackgroundProper size selection is crucial to the effective use of a laryngeal mask airway (LMA). The current choice of LMA size is based on body weight; in addition, the sex-based selection has also been suggested. However, the relationship between body weight, sex, and the dimension of hypopharynx where the LMA is positioned are inconsistent. Here we examined a tongue width-based method to determine the optimal size for the classic LMA (cLMA). MethodsThe enrolled patients had two different cLMA size selections, determined by both weight-based formula and tongue width-based method. Twenty-one male patients were studied. For the tongue width-based method, we made four rulers of different widths that corresponded to the four different cLMAs (Nos. 2.5, 3, 4, and 5) The patient was asked to open his mouth and protrude his tongue; the optimal size of cLMA was determined by the corresponding ruler which had the same tongue width of the patient. Two insertions with different-size cLMAs were randomly performed in every patient. Five parameters — frequency of insertion attempts, the presence of cuff in the mouth, end-tidal CO2 shown on monitor, oropharyngeal leak pressure, and fiberoptic score — were measured following each cLMA insertion. ResultsFor all of the five measured parameters, the tongue width-based method was better than weight-based formula in determining optimal cLMA size selection. ConclusionThe tongue width-based method is a convenient and efficacious alternative for selecting an optimal cLMA size in male adults.

Comparative efficacy and safety of the Ambu® AuraOnce™ laryngeal mask airway during general anaesthesia in adults: a systematic review and meta‐analysis

Previous comparisons between the Ambu(®) AuraOnce(™) and other laryngeal mask airways have revealed different results across various clinical studies. We aimed to perform a systematic review with meta-analysis on the efficacy and safety of the AuraOnce compared with other laryngeal mask airways for airway maintenance in adults undergoing general anaesthesia. Our search of PubMed, PubMed Central, Scopus and the Central Register of Clinical Trials of the Cochrane Collaboration yielded nine randomised controlled trials eligible for inclusion. Comparator laryngeal mask airways were the LMA Unique(™) (four trials), the LMA Classic(®) (five trials) and the Portex(®) Soft Seal(®) (three trials). The AuraOnce provided an oropharyngeal leak pressure higher than the LMA Unique (304 participants, mean (95% CI) difference 3.1 (1.6-4.7) cmH2 O, p < 0.0001) and equivalent to the LMA Classic. The Soft Seal provided a higher leak pressure than the AuraOnce (229 participants, mean (95% CI) difference 3.5 (0.4-6.7) cmH2 O, p = 0.03). Insertion was significantly faster with the AuraOnce than the LMA Unique (304 participants, mean (95% CI) difference 5.4 (2.1-8.71) s, p = 0.001) and Soft Seal (229 participants, mean (95% CI) difference 9.5 (3.0-15.9) s, p = 0.004), but similar to the LMA Classic. The first-insertion success rate of the AuraOnce was equivalent to the LMA Unique, LMA Classic and Soft Seal. We found a higher likelihood of bloodstaining on the cuff with the Soft Seal and a higher incidence of sore throat with the LMA Classic. We conclude that the AuraOnce is an effective alternative to the LMA Classic and LMA Unique, and easier to insert than all three other devices studied.