Muscle relaxant effects on insertion efficacy of the laryngeal mask ProSeal(®) in anesthetized patients: a prospective randomized controlled trial

Comparison of laryngeal mask airway (LMA) insertion with and without muscle relaxant in pediatric anesthesia; a randomized clinical trial

Introduction

This study aimed to evaluate the effectiveness of using muscle relaxant on the ease of laryngeal mask airway (LMA) insertion and possibility of its related complications.

Methods

This double-blind, randomized clinical trial was performed on 60 children aged 1–4 years with ASA (American Society of Anesthesiology) I or II with upper limb injuries who were candidates for surgery. The patients were randomly allocated to the two groups receiving atracurium group as muscle relaxant (MR) or saline group (S).

Results

Regarding ease of placement, the LMA was inserted in 66.7% and 63.3% of patients straightforwardly in the MR and S groups, respectively. While it was performed with one maneuver in 23.3% and 26.7% of cases in the MR and S groups, respectively (p = 0.955). Moreover, LMA dislodgment in the two groups was 36.7% in the MR group and 20.0% in the S group without a meaningful difference (P = 0.152). The only complication observed in the two groups was laryngospasm, which occurred in 0.10% and 13.3% in the MR and S groups, respectively (p = 0.688).

Conclusion

In some pediatric anesthesia, the use of atracurium, as a muscle relaxant had no significant effect on capability of LMA insertion, maintaining airway patency, LMA seal pressure and oxygenation variations. Moreover, it did not have a preventive effect on the occurrence of complications such as laryngospasm.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the literature on airway management has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This first of two articles addresses difficulty encountered with airway management in an unconscious patient.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians, were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence was lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Most studies comparing video laryngoscopy (VL) with direct laryngoscopy indicate a higher first attempt and overall success rate with VL, and lower complication rates. Thus, resources allowing, the CAFG now recommends use of VL with appropriately selected blade type to facilitate all tracheal intubations. If a first attempt at tracheal intubation or supraglottic airway (SGA) placement is unsuccessful, further attempts can be made as long as patient ventilation and oxygenation is maintained. Nevertheless, total attempts should be limited (to three or fewer) before declaring failure and pausing to consider "exit strategy" options. For failed intubation, exit strategy options in the still-oxygenated patient include awakening (if feasible), temporizing with an SGA, a single further attempt at tracheal intubation using a different technique, or front-of-neck airway access (FONA). Failure of tracheal intubation, face-mask ventilation, and SGA ventilation together with current or imminent hypoxemia defines a "cannot ventilate, cannot oxygenate" emergency. Neuromuscular blockade should be confirmed or established, and a single final attempt at face-mask ventilation, SGA placement, or tracheal intubation with hyper-angulated blade VL can be made, if it had not already been attempted. If ventilation remains impossible, emergency FONA should occur without delay using a scalpel-bougie-tube technique (in the adult patient). The CAFG recommends all institutions designate an individual as "airway lead" to help institute difficult airway protocols, ensure adequate training and equipment, and help with airway-related quality reviews.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 2. Planning and implementing safe management of the patient with an anticipated difficult airway

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence is lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.

Effects of neuromuscular blocking agents on the clinical performance of i-gel® and surgical condition in elderly patients undergoing hand surgery: a prospective randomized controlled trial

Background: The effects of neuromuscular blocking agents on the clinical performance of supraglottic airway devices and surgical condition in elderly patients undergoing hand surgery have not been established. We evaluated the effects of rocuronium on the clinical performance of an i-gel^® supraglottic device and surgical condition in elderly patients undergoing orthopedic hand surgery. Methods: Patients aged 65-85 years were randomized to receive either rocuronium (rocuronium group) or saline (control group). We compared the rates of successful insertion of the i-gel on the first attempt as a primary outcome and also assessed the adequacy of i-gel maintenance during controlled ventilation, anesthetic requirement, surgical condition, and recovery time. Results: The rates of successful insertion of the i-gel on a first attempt were 93.1% in the rocuronium group versus 82.1% in the control group (P = 0.423). Peak inspiratory pressure (PIP) was lower in the rocuronium group than in the control group (15.2 vs. 17.9 cmH₂O, respectively, P = 0.028). Spontaneous breathing was less common in the rocuronium group (24.1% vs. 57.1%, respectively, P = 0.011). The requirement of additional fentanyl to suppress spontaneous breathing or patient movement was less in the rocuronium group than in the control group (24.1% vs. 50.0%, respectively, P = 0.043). Surgical condition did not differ between the two groups. Recovery time was shorter in the rocuronium group than in the control group (8.4 vs. 9.9 min, respectively, P = 0.030). Conclusions: Rocuronium did not enhance the success rate of inserting the i-gel^® or the surgical condition in elderly patients. However, using rocuronium reduced PIP, the frequency of spontaneous breathing, the requirement for additional fentanyl and patients' recovery time.

The effect of rocuronium on ventilatory leak and sealing pressure using a supraglottic airway device: A randomized clinical trial

BACKGROUND

The transition of ventilatory leak and sealing pressure in supraglottic airway devices after administration of neuromuscular blocking agents is unclear. We hypothesized that ventilatory leak would decrease due to the increase in sealing pressure after administration of 0.15 and 0.30 mg/kg rocuronium iv.

METHODS

Forty patients were randomly assigned to a control group or one of two rocuronium groups. After induction of general anaesthesia, an i-gel^® was inserted before rocuronium administration. The ventilatory leak and sealing pressure were measured immediately. Then, 0.15 mg/kg or 0.30 mg/kg rocuronium iv was administered and the ventilatory leak and sealing pressure were measured again. In the control group, measurements were obtained just after insertion of the supraglottic airway device and 5 minutes later, without any additional drug administration.

RESULTS

Similar decrements in ventilatory leak of approximately 3% were registered in all three groups. There were no changes in sealing pressure in any of the groups. However, multiple logistic regression analysis demonstrated that the reduced height of the first twitch response to train-of-four stimulation after administration of rocuronium was a determinant of a decrease in sealing pressure (odds ratio: 0.97, 95% confidence interval: 0.95-0.99, P = .04).

CONCLUSIONS

Our results suggest that ventilatory leak with a supraglottic airway device decreases independently of neuromuscular blockade, although the neuromuscular blockade may potentially decrease sealing pressure. Registration of Clinical trials: UMIN Clinical Trials Registry (registration ID: UMIN000027061, URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000031018).

Guidelines on muscle relaxants and reversal in anaesthesia

OBJECTIVES

To provide an update to the 1999 French guidelines on "Muscle relaxants and reversal in anaesthesia", a consensus committee of sixteen experts was convened. A formal policy of declaration and monitoring of conflicts of interest (COI) was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were required to follow the rules of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE®) system to assess the quality of the evidence on which the recommendations were based. The potential drawbacks of making strong recommendations based on low-quality evidence were stressed. Few of the recommendations remained ungraded.

METHODS

The panel focused on eight questions: (1) In the absence of difficult mask ventilation criteria, is it necessary to check the possibility of ventilation via a facemask before muscle relaxant injection? Is it necessary to use muscle relaxants to facilitate facemask ventilation? (2) Is the use of muscle relaxants necessary to facilitate tracheal intubation? (3) Is the use of muscle relaxants necessary to facilitate the insertion of a supraglottic device and management of related complications? (4) Is it necessary to monitor neuromuscular blockade for airway management? (5) Is the use of muscle relaxants necessary to facilitate interventional procedures, and if so, which procedures? (6) Is intraoperative monitoring of neuromuscular blockade necessary? (7) What are the strategies for preventing and treating residual neuromuscular blockade? (8) What are the indications and precautions for use of both muscle relaxants and reversal agents in special populations (e.g. electroconvulsive therapy, obese patients, children, neuromuscular diseases, renal/hepatic failure, elderly patients)? All questions were formulated using the Population, Intervention, Comparison and Outcome (PICO) model for clinical questions and evidence profiles were generated. The results of the literature analysis and the recommendations were then assessed using the GRADE® system.

RESULTS

The summaries prepared by the SFAR Guideline panel resulted in thirty-one recommendations on muscle relaxants and reversal agents in anaesthesia. Of these recommendations, eleven have a high level of evidence (GRADE 1±) while twenty have a low level of evidence (GRADE 2±). No recommendations could be provided using the GRADE® system for five of the questions, and for two of these questions expert opinions were given. After two rounds of discussion and an amendment, a strong agreement was reached for all the recommendations.

CONCLUSION

Substantial agreement exists among experts regarding many strong recommendations for the improvement of practice concerning the use of muscle relaxants and reversal agents during anaesthesia. In particular, the French Society of Anaesthesia and Intensive Care (SFAR) recommends the use of a device to monitor neuromuscular blockade throughout anaesthesia.

Comparing the insertion and ventilation of laryngeal mask airway according to the patient's head position and muscle relaxation use. A prospective clinical trial

OBJECTIVES

To assess the insertion and ventilation of the laryngeal mask airway (LMA) classic while using different head positions with or without muscle relaxant.

METHODS

This is a double-blind randomized clinical trial. Patients scheduled for ureteral calculus surgery at Shanghai General Hospital, Shanghai, China were recruited between November 2017 and November 2018. A total of 132 adults were consecutively selected. Patients were randomly divided into 4 groups according to head positioning and muscle relaxant use. An 8-cm-high pillow was used to achieve the sniffing position. The insertion time, initial peak pressure (Ppeak), mean pressure (Pmean) of the airway during intermittent positive pressure ventilation (primary endpoint) and fiberoptic score of the LMA position (secondary endpoint) were evaluated via electronic bronchoscopy through the mask bar. All adverse events were recorded. Results: Data were analyzed by ANOVA, 2-way ANOVA, Chi-squared, Cochran-Mantel-Haenszel, and Kruskal-Wallis tests. The insertion time required for the first attempt, fiberoptic score, Ppeak and Pmean did not differ among the groups. However, the incidence of adverse events in groups not using muscle relaxant was higher than in those using muscle relaxant. Conclusion: Use of a sniffing position and muscle relaxant slightly eased the insertion of the LMA but did not affect the fiberoptic score or ventilation parameters. Using a muscle relaxant, but not the sniffing position, reduced the incidence of adverse effects.

AMBU® LMA® in Children With Cleft Palate for Ophthalmic Surgery: A Case Report

Airway management remains a challenge in children, and the presence of a cleft palate further complicates the scenario. Endotracheal intubation, although definitive and most preferred, may be avoided for certain short-duration procedures wherein the use of laryngeal mask airway can allow quicker emergence. We present the successful airway management of 2 pediatric patients with cleft palate undergoing ophthalmological surgery, using AMBU® LMA® as the airway device of choice, which was further used as a rescue airway device in an emergent situation of "difficult to ventilate."

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.

Comparison of the clinical performance of the flexible laryngeal mask airway in pediatric patients under general anesthesia with or without a muscle relaxant: study protocol for a randomized controlled trial

BACKGROUND

The insertion of a laryngeal mask airway (LMA) is difficult in children due to the unique features of their airways. Muscle relaxants have been reported to facilitate LMA insertion in adults; however, there is a lack of evidence supporting this in children. This trial is designed to assess the feasibility of LMA insertion with and without the use of muscle relaxants in pediatric patients under general anesthesia.

METHODS/DESIGN

This is a prospective, double-blind, single-center, parallel-arm, non-inferiority, randomized controlled trial to be conducted with participants aged 2-7 years who are undergoing elective ophthalmic surgery under general anesthesia. Participants are randomly assigned to one of two groups based on whether muscle relaxants are used (MR group, n = 64) or not used (Saline group, n = 64) prior to LMA insertion. The primary outcome is the oropharyngeal leak pressure (OLP) at a fixed gas flow of 3 L/min. The secondary outcomes are intubation time for successful insertion, ease of insertion and mask bagging, intubation attempt for successful insertion, successful insertion rate on the first attempt, fiberoptic view of the LMA position, postoperative complications, and changes in hemodynamic and ventilatory parameters.

DISCUSSION

We will compare the OLPs to determine whether the muscle relaxant provides better conditions for the manipulation of the LMA. This is the first randomized controlled trial to investigate whether muscle relaxants are beneficial to the clinical performance of LMA insertion in pediatric patients under general anesthesia. This trial will be a resource for improving the process and safety of pediatric LMA insertion under general anesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03487003 . Registered on 18 April 2018.

Does prewarming of i-gel improve insertion and ventilation in anaesthetised and paralysed patients? A prospective, randomised, control trial

Context:

I-gel are supraglottic airway devices with non-inflatable gel-like cuff that is believed to mould to body temperature, to seal the airway. Hence a pre-warmed i-gel may seal faster, provide better ventilation and superior leak pressure.

Aims:

To determine if pre-warming i-gel to 40°C improves insertion and efficacy of ventilation.

Methods and Materials:

A prospective, randomised, controlled trial was done on 64 patients requiring anaesthesia with muscle relaxation for short duration. For those in group W, i-gel warmed to 40°C for 15 minutes before insertion was used, whereas for those in group C, i-gel kept at room temperature (approximately 23°C) was used. The airway sealing pressure over time, number of attempts and time taken for a successful insertion were noted.

Statistical Analysis:

Mean sealing pressure between two groups was compared using independent sample t-test. Repeated Measures ANOVA was used to analyse mean sealing pressure at 0, 15 and 30 min. P value ≤0.05 was considered statistically significant.

Results:

Sealing pressure improves over time in both the groups but the mean sealing pressure was higher in group C when compared to group W at all points of time, however this was clinically and statistically insignificant. Ease of insertion, time for successful insertion, insertion attempts, intra-operative manoeuvres were all comparable between the groups with no adverse effects.

Conclusions:

Pre-warming of i-gel to 40°C does not improve the success rate of insertion or provide a higher sealing pressure in anaesthetised and paralysed patients when compared to i-gel at room temperature.

A Comparison between the i-gel® and air-Q® Supraglottic Airway Devices Used for the Patients Undergoing General Anesthesia with Muscle Relaxation

OBJECTIVES

The aim of the present study was to compare two supraglottic airway (SGA) devices (i.e., the i-gel® © Intersurgical Ltd and air-Q® (Reusable) Cookgas company) in terms of the insertion time, amount of leak during ventilation with maximum positive pressure, and postoperative complications in patients referring to Modarres Hospital in Tehran.

METHOD

The present double-blind clinical trial was performed on 60 patients undergoing elective surgeries that required general anesthesia with muscle relaxation. Patients were randomly assigned to either i-gel® (n = 30) or Air-Q® (n = 30) groups.

RESULTS

The mean age, body mass index, duration of surgery, duration of anesthesia, and gender ratio were not significantly different between the two groups. Mean ± SD values of the SGA devices' insertion time (in seconds) in the air-Q® and i-gel® groups were 4.87 ± 1.6 and 6.80 ± 1.2, respectively (P < 0.001). The mean OLP in the Air-Q® group was significantly higher than that of the i-gel® group (35.9 ± 9.6 versus 24.8 ± 3.7, p < 0.001). The frequency of complications occurred after the supraglottic airway insertion was higher in the i-gel® group. However, only in terms of sore throat, the difference between the two groups was statistically significant: 6 (20%) had sore throat (P = 0.024) in the i-gel groups, but in in the Air-Q® groups no one had this side effect after surgery.

CONCLUSION

It was concluded that the Air-Q® supraglottic airway was placed faster and easier with fewer complications than the i-gel in general anesthesia with muscle relaxation. The frequency of the occurrence of all three complications, cough, sore throat, and blood, on the cuff (6 (20%) was higher in the i-gel group than that in the air-Q® group (cough3 (10%), sore throat 0 (0%), and blood on the cuff 3 (10%) (P < 0.05).

Comparison of the clinical performance of airway management with the i-gel® and laryngeal mask airway SupremeTM in geriatric patients: a prospective and randomized study

Background

Geriatric patients are susceptible to respiratory and hemodynamic adverse events during endotracheal intubation and extubation due to anatomic and physiological changes with aging. Supraglottic airway devices (SADs) provide reduced airway morbidity and increased hemodynamic stability in adults. However, studies that have compared the clinical performance of SADs in geriatric patients are limited. Therefore, we evaluated the clinical performance of airway management with i-gel^® and laryngeal mask airway Supreme (LMA Supreme^TM) in geriatric patients.

Methods

The subjects were American Society of Anesthesiologists physical status classification I–III geriatric (65–85 years) patients who underwent elective surgery with general anesthesia and were randomly allocated into the i-gel^® group and the LMA Supreme^TM group. We compared the time for successful insertion on a first attempt as a primary outcome, and the secondary outcomes were success rate, ease of insertion, maneuver for successful ventilation, oropharyngeal leak pressure, gastric insufflation, fiberoptic view grades, ventilator problems, and adverse events.

Results

Insertion time was significantly shorter for the i-gel^® than the LMA Supreme^TM (21.4 ± 6.8 vs. 29.3 ± 9.9 s; P = 0.011). The i-gel^® was also easier to insert than the LMA Supreme^TM (P = 0.014). Gastric insufflation was less frequent with the i-gel^® than the LMA Supreme^TM (0% vs. 31.3%; P = 0.013). Other measurements were comparable between groups.

Conclusions

Both devices can be safely applied to geriatric patients with similar success rates and oropharyngeal leak pressures. However, inserting the i-gel^® was faster and easier compared to the LMA Supreme^TM in geriatric patients.

Optimal propofol dosage for i-gel® insertion in healthy paralyzed patients

Background

Propofol is used for supraglottic airway device insertion, often with the i-gel. However, the propofol requirement for i-gel insertion has not been explored in paralyzed patients. This study was performed to explore hemodynamic changes and sedation level with different propofol doses in healthy paralyzed patients when the i-gel was inserted.

Methods

A total of 141 patients undergoing a urologic operation were randomly allocated to three groups depending on the propofol dose (1.5, 2, and 2.5 mg/kg; Groups P1.5, P2, and P2.5, respectively). After patients had been administered each propofol dose and rocuronium, the i-gel was inserted and changes in hemodynamic parameters and bispectral index were evaluated.

Results

Group P2 showed a lower incidence of complications (17%) such as hemodynamic instability and inadequate sedation than Group P1.5 (55.3%, P < 0.001) or Group P2.5 (40.4%, P = 0.012). The incidence and dose of additional propofol increased in Group P1.5 (51%, median [range]; 20 [0–50]) compared with those in the other groups (0%, 0 [0–0] in Group P2 and 8.5%, 0 [0–50] in Group P2.5, all P < 0.001), and the incidence and dose of additional ephedrine were significantly higher in Group P2.5 (31.9%; 0 [0–20]) than in Group P1.5 (10.6%, P = 0.012; 0 [0–5], P = 0.007, respectively).

Conclusions

For the stable maintenance of hemodynamic parameters and proper sedation level during i-gel insertion, 2 mg/kg propofol has an advantage over 1.5 mg/kg or 2.5 mg/kg propofol in healthy paralyzed patients.

Effect of Cricoid Pressure on the Insertion Efficacy of Six Supraglottic Devices: A Crossover Randomized Simulation Trial

BACKGROUND

No study has ever compared the efficacy of various types of supraglottic devices (SGDs) for securing the airway under cricoid pressure.

OBJECTIVE

This study aimed to evaluate the efficacy of six SGDs, LMA-ProSeal (ProSeal), LMA-Classic (Classic), Laryngeal Tube (LT), LMA-Supreme (Supreme), air-Q (air-Q), and i-gel (i-gel), in airway management under cricoid pressure using a manikin.

METHODS

Fifteen novice doctors and 16 experienced doctors used the six SGDs under cricoid or sham pressure on an adult manikin. Insertion time, successful ventilation rate, and subjective insertion difficulty on a visual analogue scale (VAS) were measured.

RESULTS

Both novice and experienced doctors had a significantly lower ventilation success rate under cricoid pressure than under sham pressure when using the ProSeal, Classic, and LT, but not when using the other three SGDs. Novice doctors required a significantly longer insertion time under cricoid pressure than under sham pressure with all SGDs. Experienced doctors required a significantly longer insertion time under cricoid pressure than with sham pressure when using the ProSeal, Classic, and LT, but not when using the other three SGDs. Subjective insertion difficulty on VAS was significantly higher under cricoid pressure than under sham pressure with all six SGDs.

CONCLUSION

Ventilation success rate under cricoid pressure was significantly lower than under sham pressure when using the ProSeal, Classic, and LT, but not when using the other three SGDs in both novice and experienced doctors.

Optimal dose of succinylcholine for laryngeal mask airway insertion: systematic review, meta-analysis and metaregression of randomised control trials

OBJECTIVES

To evaluate the optimal dose of succinylcholine for laryngeal mask airway (LMA) insertion and all related morbidities.

DESIGN

Systematic review, meta-analysis and metaregression of randomised controlled trials (RCTs).

DATA SOURCE AND STUDY ELIGIBILITY CRITERIA

A comprehensive search of RCTs in the PubMed, Embase, the Cochrane Library and the ClinicalTrials.gov registry up to July 2016 and articles that evaluated the use of succinylcholine chloride for LMA insertion were included in the analyses. The relative risk (RR) and the corresponding 95% CIs were determined.

INTERVENTION

Succinylcholine as the coinduction agent and the doses were divided into mini (≤0.3 mg/kg) and low (0.3-1.0 mg/kg) doses for dose-dependent effect analyses.

PRIMARY AND SECONDARY OUTCOMES

The primary outcome was the first-attempt LMA insertion failure rate. Secondary outcomes included all related adverse events.

RESULTS

Data from 10 RCTs comprising 625 participants showed that succinylcholine reduced the first-attempt LMA insertion failure rate (RR, 0.22; 95% CI 0.12 to 0.43), coughing and gagging (RR, 0.26; 95% CI 0.15 to 0.45) and laryngospasm (RR, 0.14; 95% CI 0.05 to 0.39). The use of succinylcholine did not result in a significant increase of postoperative myalgia (RR, 2.58; 95% CI 0.79 to 8.44) and did not reduce the risk of postoperative sore throat (RR, 0.76; 95% CI 0.55 to 1.03). Subgroup analysis further showed that low-dose succinylcholine reduced the LMA insertion failure rate and its related coughing and gagging when compared with mini dose.

CONCLUSION

The use of succinylcholine compared with none can facilitate LMA insertion and reduce insertion-related reflexes without significant postoperative myalgia. However, additional prospective studies with a larger sample size are required to fully evaluate the dose-dependent effect and complications of succinylcholine for LMA insertion.

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

In the crowded world of supraglottic airway devices (SADs), many papers compare the easiness of insertion based on the different endpoints of an operator's satisfaction: first pass success, ventilation effectiveness, complications and morbidity. Proseal LMA^™ (Laryngeal Mask Airway, Teleflex Medical, Dublin, Ireland) has been extensively studied because on one hand it has a steeper learning curve and more complex insertion when compared with other SADs and on the other hand many alternative techniques are available to facilitate insertion. This research is part of a larger body of studies exploring the issue that some devices are more difficult to insert because of many features related to sizing, constructive material, airway conduit and cuff design, performance and last but not least experience. Nevertheless, the biggest question might be the search for a systematic categorization of insertion difficulty features and identification of criteria allowing the choice for the best device and consequently for the best insertion technique. Given that, as a result of many intrinsic characteristics of the device we are using, insertion might become the secondary issue to be considered only after we clearly identify what makes it difficult, and to be counterbalanced on the results we expect from the device, performance we can achieve and degree of airway protection it could grant. The aim of this narrative review is to consider which factors might affect or condition SAD insertion difficulty and to try identifying some criteria addressing physicians pertaining to the use of SADs in clinical practice.

Effects of stylet use during tracheal intubation on postoperative pharyngeal pain in anesthetized patients: A prospective randomized controlled trial

STUDY OBJECTIVE

This study aimed to compare the impact of stylet application for tracheal intubation for postoperative pharyngeal pain or hoarseness in patients undergoing elective surgery.

DESIGN

Randomized clinical trial.

SETTING

Operating room.

PATIENTS

Forty adult patients scheduled for elective surgery under tracheal intubation with an ASA physical status of 1-3.

INTERVENTIONS

Tracheal intubation was performed by anesthesiologists with stylet group (Stylet group; 20 patients) or without stylet group (Control group; 20 patients).

MEASUREMENTS

Incidence of postoperative pharyngeal pain or hoarseness was assessed.

MAIN RESULTS

The incidence of postoperative pharyngeal pain was significantly higher in the Stylet group (10/20 patients) than in the Control group (2/20 patients) (P=0.013). The incidence of hoarseness did not significantly differ between the Stylet group (6/20 patients) and the Control group (3/20 patients) (P=0.45).

CONCLUSIONS

Stylet use increases the incidence of postoperative pharyngeal pain.

LMA-ProSeal insertion by novice doctors as affected by a 90° bend created by an intubating stylet: a randomized clinical trial

STUDY OBJECTIVE

This study aimed to test the hypothesis that insertion of the supraglottic device LMA-ProSeal (ProSeal) by novice doctors in anesthetized patients can be improved by using an intubating stylet to create a 90° bend and that better sealing pressure is achieved.

DESIGN

Randomized clinical trial.

SETTING

Operating room.

PATIENTS

Seventy adult patients scheduled for elective surgery under general anesthesia using ProSeal with American Society of Anesthesiologists physical status 1 to 3.

INTERVENTIONS

ProSeal were inserted with the 90° bend created by the intubating stylet (90D group, 35 patients) or not (ie, conventional insertion; C group, 35 patients).

MEASUREMENTS

The number of attempts to successful insertion, sealing pressure, subjective difficulty of insertion by novice doctors, and postoperative pharyngeal pain or hoarseness were compared between groups.

MAIN RESULTS

The total number of insertion attempts for the 90D and control groups were 1 (24 and 8, respectively), 2 (8 and 13), 3 (3 and 9), and failure (0 and 5), respectively, showing significant differences between groups (P<.001). Sealing pressure was significantly higher in the 90D group than in the C group (90D group, 23.3±3.7cm H2O; C group, 19.5±2.6cm H2O; P<.001), and the subjective difficulty of insertion was significantly lower in the 90D group (90D group, 27.3±17.6mm; C group, 55.4±22.8mm; P<.001). The incidence of postoperative pharyngeal pain and hoarseness did not differ significantly between groups.

CONCLUSIONS

Our results suggest that creating a 90° bend using an intubating stylet facilitates ProSeal insertion by novice doctors, as reflected by higher successful insertion rates, higher sealing pressure, and lower subjective difficulty of insertion in anesthetized patients.

A comparison of the effectiveness of the streamlined liner of pharyngeal airway in paralyzed and nonparalyzed patients undergoing gynecological surgery: a randomized trial

STUDY OBJECTIVE

To compare the effectiveness of streamlined liner of pharyngeal airway (SLIPA) in paralyzed and nonparalyzed, anesthetized patients undergoing gynecological surgery.

DESIGN

Prospective randomized double-blind clinical trial.

SETTING

Intraoperative.

PATIENTS

A total of 80 female patients with American Society of Anesthesiologists class I or II and who were undergoing gynecological surgery.

INTERVENTIONS

The patients were randomly allocated to either the nonparalyzed group (group NR, n=40) or the paralyzed group (group R, n=40).

MEASUREMENTS

Oropharyngeal leakage pressure was the primary outcome. Insertion time; number of insertion attempts; success rate at first insertion; involuntary movement; peak inspiratory pressure (PIP); leakage fraction; hemodynamic changes; complications, such as blood tinging, regurgitation, and sore throat; and recovery time were also evaluated for secondary outcomes.

MAIN RESULTS

Oropharyngeal leakage pressure, which is primary outcome, was no difference among the groups. Insertion time, number of insertion attempts, success rate at first insertion, involuntary movement, leakage fraction, hemodynamic changes, and complications were not statistically different among the groups. The PIP in group NR was significantly increased compared to that of group R (P=.002). Recovery time was significantly longer in group R than in group NR (P<.001).

CONCLUSIONS

SLIPA had good performance in both paralyzed and nonparalyzed patients. There was no difference in SLIPA performance or complications irrespective of muscle relaxant use, except decrease in PIP and prolong recovery time in paralyzed patients.

A comparison of classic laryngeal mask airway insertion between lightwand- and standard index finger-guided techniques

STUDY OBJECTIVE

To compare the efficacy of lightwand-guided classic laryngeal mask airway (cLMA) real-time insertion technique with the standard recommended index finger-guided insertion technique.

DESIGN

Prospective, randomized controlled study.

SETTING

University-affiliated hospital.

PATIENTS

Three hundred patients undergoing minor gynecological or orthopedic surgeries under general anesthesia using the cLMA as an airway management tool.

INTERVENTIONS

Patients were randomly divided into either lightwand-guided group or standard group.

MEASUREMENTS

Fiberoptic bronchoscopy was used to determine the cLMA position after a cLMA was inserted. The first attempt and total success rates of the cLMA insertion, insertion time, distances from the end of cLMA pilot tube to the upper central incisors, views of fiberoptic bronchoscopy, blood staining, tidal volume, airway pressure, end-tidal CO2, SpO2, noninvasive hemodynamic parameters, and others were compared.

MAIN RESULTS

The cLMA was all successfully inserted within 3 attempts except for 2 patients in the standard group. The success rates of lightwand-guided insertion technique at first attempt were significantly higher than standard insertion technique; the ideal view rates assessed by fiberoptic bronchoscopy in lightwand-guided group patients were also significantly higher than in standard group patients, but the insertion time of first successful attempt was similar; the blood staining rates on the cLMA in lightwand-guided group patients were significantly less than in standard group patients. The depths of cLMA insertion in standard group patients were significantly deeper than those in lightwand-guided group patients. There was no significant difference in end-tidal CO2, SpO2, airway pressure, and hemodynamic variables.

CONCLUSION

Lightwand-guided cLMA insertion technique can provide a more objective indicator for correct cLMA positioning, higher first attempt success rates, better glottic views, and less damage to oropharyngeal or esophagus tissues than standard index finger-guided cLMA insertion technique.

Muscle relaxant facilitates i-gel insertion by novice doctors: A prospective randomized controlled trial

STUDY OBJECTIVE

This study aimed to determine whether muscle relaxants facilitates insertion efficacy of the i-gel supraglottic device (i-gel) by novice doctors in anesthetized patients.

DESIGN

Randomized clinical trial.

SETTING

Operating room.

PATIENTS

Seventy adult patients scheduled for elective surgery under general anesthesia.

INTERVENTIONS

Seventy adult patients were assigned to the rocuronium (MR group; 35 patients) or control group (C group; 35 patients). Anesthesia was induced with propofol and remifentanil, and 0.9mgkg(-1) rocuronium was administered in the MR group.

MEASUREMENTS

The number of attempts to successful insertion, sealing pressure, and subjective difficulty of insertion were compared between the groups.

MAIN RESULTS

The total number of insertion attempts were as follows: one (MR group, 17 cases; C group, 4 cases), two (MR group, 13 cases; C group, 14 cases), three (MR group, 4 cases; C group, 14 cases), and failure (MR group, 1 case; C group, 3 cases), which was significantly different (P<.001). Sealing pressure was significantly higher in the MR group than in the C group (MR group, 22.1±5.4 cmH2O; C group, 18.7±3.2 cmH2O, P<.001). Subjective difficulty of insertion was significantly lower in the MR group than in the C group (C group, 72.4±19.0mm; MR group, 29.4±18.3mm; P<.001).

CONCLUSIONS

Our randomized clinical trial suggests that muscle relaxation facilitates i-gel insertion efficacy in anesthetized patients, as assessed by successful insertion rate, sealing pressure, and subjective difficulty of insertion.

Evaluation of double-lumen endotracheal tube extubation force by extraction angle: a prospective randomized clinical trial

STUDY OBJECTIVE

Gentle and noninvasive double-lumen tracheal tube (DLT) extubation is important for both airway and circulatory management, especially after lung resection. We performed a prospective randomized clinical trial comparing DLT extubation force based on 2 different extraction angles.

DESIGN

Randomized clinical trial.

SETTING

Operating room.

PATIENTS

Sixty adult patients scheduled for elective surgery under general anesthesia using DLT with ASA physical status 1 to 3.

INTERVENTIONS

Sixty patients who underwent lung resection with a DLT were randomly assigned to extraction angles of 60° (30 patients) and 90° (30 patients) relative to the ground.

MEASUREMENTS

Extubation forces and changes in vital signs were compared between groups. Results were analysed with the Mann-Whitney U test, non-paired t test, and χ(2) test. P<.05 was considered significant.

MAIN RESULTS

Less extraction force was needed at 60° compared to 90° (90°, 13.9±2.3 N; 60°; 7.1±2.1 N; P<.001). The rate of increase in systolic and diastolic blood pressure (post-extubation/pre-extubation) was significantly smaller at 60° than at 90° (systolic blood pressure, P<.001; diastolic blood pressure, P=.002).

CONCLUSIONS

Our findings suggest that DLT extubation at 60° requires less force than at 90° and was accompanied by a smaller increase in blood pressure. Thus, extraction at 60° may be less invasive and beneficial for patients undergoing DLT extubation.

Cricoid pressure impedes tracheal intubation with the Pentax-AWS Airwayscope®: a prospective randomized trial

BACKGROUND

It is unclear how cricoid pressure affects tracheal intubation with the Pentax-AWS Airwayscope(®) (AWS). We conducted a prospective randomized clinical trial in anaesthetized patients.

METHODS

Sixty patients were allocated to either the cricoid pressure (CP) group (n=30) or the sham group (n=30). We compared the two groups with regard to intubation time, number of attempts required for insertion of the Intlock blade (disposable blade of the AWS) and tracheal intubation, percentage of glottic opening (POGO) score, and subjective difficulty of both laryngoscopy and passage of a tube through the glottis.

RESULTS

Intubation time was significantly longer in the CP group (median 45[IQR40-59] s) than in the sham group (32[28-45] s) (P=0.003, 95% CI for median difference 5-24 s). The number required for insertion of the Intlock blade did not differ between the groups (P=0.08), but the number for tracheal intubation was significantly higher in the CP group (1 attempt in 14 patients, 2 in 7, 3 in 9) than in the sham group (1 attempt in 24 patients, 2 in 6; P=0.002). POGO score did not differ significantly between the groups (P=0.60), nor did the subjective difficulty of laryngoscopy (P=0.06). The visual analogue scale score for passage of a tube through the glottis was significantly higher in the CP group than in the sham group (P<0.001).

CONCLUSIONS

Cricoid pressure impedes tracheal intubation using the AWS, and is associated with longer intubation time, which can be attributed to increased difficulty in the passage of a tube through the glottis.

CLINICAL TRIAL REGISTRY NUMBER

UMIN000018209.

Laryngoscopy facilitates successful i-gel insertion by novice doctors: a prospective randomized controlled trial

BACKGROUND

This study investigated the hypothesis that the efficacy of insertion of the supraglottic device i-gel(®) (i-gel) can be improved by laryngoscopy and can provide better sealing pressure in anesthetized patients by novice doctors.

METHODS

Eighty-four adult patients were assigned to the laryngoscopy group (L group, 42 patients) or control group (i.e., conventional blind insertion; C group, 42 patients). Anesthesia was induced with propofol and remifentanil, and rocuronium 0.6-0.9 mg/kg was administered. The number of attempts until successful insertion, sealing pressure, vital sign changes upon insertion, and subjective difficulty of insertion by novice doctors were compared between the groups.

RESULTS

The total number of insertion attempts was one (L group 36 cases, C group 23 cases), two (L group 6 cases, C group 18 cases), and three (L group 0 case, C group 1 case), with significant differences between groups (P = 0.007). The sealing pressure was significantly higher in the L group than in the C group (L group 22.3 ± 2.6 cmH2O, C group 19.5 ± 2.7 cmH2O, P < 0.001). Vital sign changes (heart rate and blood pressure) did not differ between the two groups. The subjective difficulty of insertion was significantly lower in the L group than in the C group (L group 26.8 ± 11.8 mm, C group 47.0 ± 15.1 mm, P < 0.001). The incidence of postoperative pharyngeal pain was significantly lower in the L group than in the C group (P < 0.001), while the incidence of hoarseness did not differ between the two groups (P = 1.00).

CONCLUSION

Our results suggest that laryngoscopy facilitates i-gel insertion by novice doctors, as reflected in the rate of successful insertions, higher sealing pressure, and lower subjective difficulty of insertion in anesthetized patients.