Time to consider supraglottic airway device oropharyngeal leak pressure measurement more objectively

Supraglottic Airway Devices: Present State and Outlook for 2050

Correct placement of supraglottic airway devices (SGDs) is crucial for patient safety and of prime concern of anesthesiologists who want to provide effective and efficient airway management to their patients undergoing surgery or procedures requiring anesthesia care. In the majority of cases, blind insertion of SGDs results in less-than-optimal anatomical and functional positioning of the airway devices. Malpositioning can cause clinical malfunction and result in interference with gas exchange, loss-of-airway, gastric inflation, and aspiration of gastric contents. A close match is needed between the shape and profile of SGDs and the laryngeal inlet. An adequate first seal (with the respiratory tract) and a good fit at the second seal of the distal cuff and the gastrointestinal tract are most desirable. Vision-guided insertion techniques are ideal and should be the way forward. This article recommends the use of third-generation vision-incorporated-video SGDs, which allow for direct visualization of the insertion process, corrective maneuvers, and, when necessary, insertion of a nasogastric tube (NGT) and/or endotracheal tube (ETT) intubation. A videoscope embedded within the SGD allows a visual check of the glottis opening and position of the epiglottis. This design affords the benefit of confirming and/or correcting a SGD's position in the midline and rotation in the sagittal plane. The first clinically available video laryngeal mask airways (VLMAs) and multiple prototypes are being tested and used in anesthesia. Existing VLMAs are still not perfect, and further improvements are recommended. Additional modifications in multicamera technology, to obtain a panoramic view of the SGD sitting correctly in the hypopharynx and to prove that correct sizes have been used, are in the process of production. Ultimately, any device inserted orally-SGD, ETT, NGT, temperature probe, transesophageal scope, neural integrity monitor (NIM) tubes-could benefit from correct vision-guided positioning. VLMAs also allow for automatic recording, which can be documented in clinical records of patients, and could be valuable during teaching and research, with potential value in case of legal defence (with an airway incident). If difficulties occur with the airway, documentation in the patient's file may help future anesthesiologists to better understand the real-time problems. Both manufacturers and designers of SGDs may learn from optimally positioned SGDs to improve the design of these airway devices.

Supraglottic airway device versus tracheal tube for pediatric laparoscopic surgery-A systematic review and meta-analysis

BACKGROUND

Conventionally, tracheal tubes have been used for general anesthesia in pediatric laparoscopic surgeries. Recently, supraglottic devices are being used for the same. The performance of supraglottic devices versus tracheal tubes in children undergoing laparoscopic surgery is uncertain.

METHODS

A systematic review and meta-analysis of randomized controlled trials that compared supraglottic devices versus tracheal tubes in patients ≤18 years undergoing laparoscopic surgery under general anesthesia was conducted. The outcomes were peak airway pressures (cm H2 O), end-tidal carbon dioxide during pneumoperitoneum (mm Hg), recovery time (min), postoperative sore throat and adverse events. Mean difference and odds ratio, with 95% confidence intervals were reported using a random effect model.

RESULTS

Eight trials (n = 591) were included in the final meta-analysis. There was no statistically significant difference in the peak airway pressures (MD 0.58, 95% CI: -0.65 to 1.8; p = .36) and end-tidal carbon dioxide (MD -0.60, 95% CI: -2.00 to 0.80; p = .40) during pneumoperitoneum in the supraglottic device and the tracheal tube group. The tracheal tube group had higher odds of sore throat (OR 3.30, 95% CI: 1.69-6.45; p = .0005) and the supraglottic airway group had faster recovery time (MD 4.21, 95% CI: 3.12-5.31; p < .0001), which were statistically significant. The certainty of evidence is graded low.

CONCLUSION

There is low quality evidence to suggest that for pediatric laparoscopic surgeries of short duration, supraglottic devices could provide comparable intraoperative ventilation in terms of peak airway pressures and end tidal carbon dioxide, with lower odds of postoperative sore throat and faster recovery time when compared to tracheal tubes.

Comparison of clinical performance of Baska mask and Ambu AuraGain in patients undergoing surgery: A single-blinded, randomised comparative trial

Background and Aims

The Baska mask (BM) and the Ambu AuraGain (AAG) have shown promising results in recent trials but have not been compared. Therefore, we aimed to compare the clinical performance of the BM and the AAG for airway management of adult patients.

Methods

In this randomised comparative study, patients aged 18-60 years and with an expected surgical duration of less than 2 h were enroled. Patients were randomly allocated to AAG (Group A, n = 37) and BM (Group B, n = 37) for airway management. After induction of anaesthesia, an allocated supraglottic airway device (SAD) was inserted. Oropharyngeal leak pressure (OLP), time taken to insert SAD, number of insertion attempts, leak fraction (LF), first-attempt success rate, overall success rate, ease of insertion, fiberoptic view of the glottis, and complications were compared. The data were analysed using Student's t-test, Mann-Whitney U test, and Fisher's exact tests.

Results

Baseline and demographic characteristics were comparable. OLP (31.32 ± 2.59 versus 27.54 ± 1.32 cmH2O) was higher (P < 0.001), and LF (6.19% ± 1.20% versus 7.24% ± 1.72%) was lower (P = 0.003) in the BM group. First-attempt and overall success rate, time taken to insert, number of insertion attempts, ease of insertion, and fibreoptic view of glottis through the SADs were statistically similar between groups. However, the incidence of sore throat (P = 0.007) and cough (P = 0.028) was higher with AAG.

Conclusion

Clinical performance of BM was better than AAG as the former had higher OLP, lower LF and complications.

To compare the influence of blind insertion and up-down optimized glottic exposure manoeuvre on oropharyngeal leak pressure using SaCoVLM™ video laryngeal mask among patients undergoing general anesthesia

To compare the potential influences of blind insertion and up-down optimized glottic exposure manoeuvre on the oropharyngeal leak pressure (OPLP) in using SaCoVLM™ video laryngeal mask (VLM) among patients undergoing general anesthesia. A randomized self-control study controlled was conducted to investigate the effect of two insertion techniques on OPLP. A total of 60 patients (male or female, 18-78 years, BMI 18.0-30.0 kg m-2 and ASA I-II) receiving selective surgery under general anesthesia were randomly recruited. After induction of anesthesia, the SaCoVLM™ was inserted by blind insertion manoeuvre. The glottic exposure grading(V1) of the SaCoVLM™ visual laryngeal mask and the OPLP(P1) were recorded. And the glottic exposure grading(V2) and OPLP(P2) of SaCoVLM™ were recorded again when the glottic exposure grading was optimal. The glottis exposure grading and OPLP were compared before and after different insertion manoeuver. The glottic exposure grading (V2) obtained by using up-down optimized glottic exposure manoeuvre was better than that obtained by using blind insertion manoeuvre (V1)(P < 0.001). The OPLP was significantly lower in the blind insertion manoeuvre (P1) than in the up-down optimized glottic exposure manoeuvre (P2) (32.4 ± 5.0 cmH2O vs. 36.3 ± 5.2 cmH2O, P < 0.001). In using SaCoVLM™, higher OPLP and better glottic exposure grading were achieved through up-down optimized glottic exposure manoeuvre, protecting the airway while real-time monitoring of conditions around the glottis, which significantly improves airway safety. Our results suggests that up-down optimized glottic exposure manoeuver may be a useful technique for SaCoVLM™ insertion.Trial registration: ChiCTR, ChiCTR2000028802. Registered 4 January 2020, http://www.chictr.org.cn/ChiCTR2000028802.

Comparison of oropharyngeal leak pressure of I-gelTM and BlockbusterTM laryngeal mask airway in anaesthetized pediatric patients

BACKGROUND

Supraglottic airways (SGA) are increasingly used in pediatric anesthesia.Among SGA, I-gelTM is a commonly used device in pediatric patients. The BlockbusterTM laryngeal mask airway (LMA) is latest addition in pediatric airway armamentarium. This studywas conducted to compare the clinical performance of I-gelTM and BlockbusterTM LMA in pediatric patients.

METHODS

A total of 140 children aged 1-5 years, who were undergoing elective surgery,were randomized into two groups either I-gelTM (Group I) or BlockbusterTM LMA (Group B). Airway was secured with appropriate-sized LMA according to group allocation under generalanesthesia. The primary objective of study was oropharyngeal leak pressures (OPLP), andsecondary objectives were number of attempts of device insertion, success rate, ease ofLMA insertion, hemodynamic parameters, and postoperative pharyngolaryngeal morbidities.

RESULTS

The mean OPLP was significantly higher for I-gelTM compared to BlockbusterTM LMA(27.97 ± 1.65 vs. 26.04 ± 2.12; P < 0.001). The devices were successfully inserted on thefirst attempt in 97.14% and 90% of the Group I and Group B respectively. The insertion time,ease of insertion, hemodynamic parameters and postoperative complications were comparable between groups.

CONCLUSIONS

The I-gelTM was more efficacious device in term of OPLP than BlockbusterTMLMA for positive pressure ventilation in pediatric patients undergoing short surgical procedures under general anesthesia.

Blind vs. video-laryngoscope-guided laryngeal mask insertion: A prospective randomized comparison of oropharyngeal leak pressure and fiberoptic grading

PURPOSE

Laryngeal Mask Airway (LMA) insertion may not always be smooth without complications. Controversial results of several studies evaluating ideal insertion conditions have been published. This study compared the oropharyngeal leak pressure values and fiberoptic grading scores between blind and video-laryngoscope-guided LMA insertion.

METHODS

Patients were randomly assigned into blind insertion (n = 50) and video-laryngoscope guided insertion (n = 50) groups. The oropharyngeal leak pressure, peak airway pressure, fiberoptic grading score, first attempt success rate, hemodynamic parameters, and complications were recorded.

RESULTS

All laryngeal mask airways were successfully inserted in both groups at the first attempt. The fiberoptic staging scores were: grade 1 in 8.2% of patients, grade 2 in 24.4% of patients, grade 3 in 44.8% of patients, grade 4 in 22.4% of patients in the control group. On the other hand, grade 1 in 2.2% of patients, grade 2 in 28.6% of patients, grade 3 in 51% of patients, grade 4 in 8.2% of patients in the VL group (p = 0.260). The peak airway pressure and LMA insertion time were similar between groups. However, the oropharyngeal leak pressure before extubation was significantly higher in the video-laryngoscope-guided insertion than blind insertion (36.29 ± 7.09 vs. 33.79 ± 8.84 cmH2O respectively, p = 0.04).

CONCLUSIONS

The findings of our study suggest that the video-laryngoscope-guided LMA-Classic insertion with a standard blade technique may be a helpful alternative to blind insertion.

Evaluation of the insertion parameters and complications of the i-gel Plus airway device for maintaining patent airway during planned procedures under general anaesthesia: a protocol for a prospective multicentre cohort study

INTRODUCTION

Supraglottic airway devices represent a less invasive method of airway management than tracheal intubation during general anaesthesia. Their continued development is focused mainly on improvements in the insertion success rate and minimalisation of perioperative and postoperative complications. The i-gel Plus is a novel, anatomically preshaped supraglottic airway device which achieves a perilaryngeal seal due to a non-inflatable cuff made of a soft thermoplastic elastomer. The purpose of this cohort study is to assess the success rate of the i-gel Plus use during elective procedures under general anaesthesia, its intraoperative performance, and the degree of postoperative complications.

METHODS AND ANALYSIS

This is a multicentre, prospective, interventional cohort study. The enrolment will take place in seven centres in four European countries. We plan to enrol 2000 adult patients in total, who are scheduled for elective surgery under general anaesthesia, and with an indication for use of a supraglottic airway device for management of their airway. The study is projected to run over a period of 18 months. The primary outcome of the study is the total success rate of the i-gel Plus insertion in terms of successful ventilation and oxygenation through the device. Secondary outcomes include perioperative parameters, such as insertion time, seal/leak pressures, number of insertion attempts and postoperative adverse events and complications. Postoperative follow-up will be performed at 1 hour, 24 hours in all patients, and for selected patients at 3 and 6 months.

ETHICS AND DISSEMINATION

The cohort study has received the following ethical approvals: General University Hospital Prague, University Hospital Olomouc, University Military Hospital Prague, University Hospital Barcelona, University Hospital Lodz, Antrim Area Hospital, Craigavon Area Hospital, Office for Research Ethics Committees Northern Ireland. The results will be published in peer-reviewed journals and presented at relevant anaesthesia conferences.

TRIAL REGISTRATION NUMBER

ISRCTN86233693;Pre-results.

Features of new vision-incorporated third-generation video laryngeal mask airways

Numerous studies have shown that blindly inserted supraglottic airway devices (SADs) are sub-optimally placed in 50 to 80% of all cases. Placement under direct vision has been recommended. We describe the very first two new SADs of the third generation that incorporate a videoscope with flexible tip. Both devices are made up of two interlocking components-the SAD and a videoscope. The 3rd generation, direct vision SADs allow vision-guided insertion, corrective manoeuvres, if needed, and correct placement in the hypopharynx and possess additional features which permit insertion of a gastric tube and endotracheal intubation should the need arise. This article describes the two new devices' physical characteristics, features, rationale for use, advantages and limitations in comparison to existing devices. Each of the two new devices-the Video Laryngeal Mask (VLM^TM, UE Medical®) and the SafeLM® Video Laryngeal Mask System (SafeLM^TM VLMS, Magill Medical Technology®) consist of two parts: (a) a disposable 2nd generation SAD with a silicone cuff and an anatomically curved tube; and (b) a reusable patient-isolated videoscope and monitoring screen, with the flexible scope located into a specially-designed, blind-end channel terminating in the bowl of the SAD, preventing the videoscope from contacting patient body fluids in the SAD bowl. Third generation placement-under-direct-vision supraglottic airway devices possess several theoretical safety and ease of use advantages which now need to be validated in clinical use.

Prewarming i-gel laryngeal mask for mechanical ventilation: a meta-analysis of randomised control trials and trial sequential analysis

OBJECTIVE

To systematically evaluate the efficiency of prewarming i-gel laryngeal mask for mechanical ventilation by meta-analysis and trial sequential analysis.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Cochrane library, Web of Science, Ovid Medline and PubMed were searched from their inception to 31 August 2020. Only articles published in English language were considered.

METHODS

Randomised controlled trials (RCTs) comparing the efficiency of prewarming i-gel laryngeal mask versus keeping it at room temperature for mechanical ventilation were included. Primary outcome was sealing pressure immediately after successful ventilation. Secondary outcomes were the first-attempt insertion success rate and the incidence of postoperative pharyngeal pain. Two authors independently selected studies. Quality analysis was performed using the modified Jadad Scale. Trial sequential analysis (TSA) was used to control risk of random errors. Sensitivity analysis was done to assess the effect of a single study on the pooled estimates. Publication bias was assessed by funnel plots and Egger's regression test.

RESULTS

Four RCTs comprising 374 patients were included. The results of meta-analysis showed that compared with the control group, prewarming i-gel laryngeal mask provides a higher sealing pressure immediately after successful ventilation (mean difference 2.19 cm H₂O; 95% CI (1.17 to 3.21); p<0.0001; high quality), with firm evidence from TSA and lower publication bias (p=0.7372). No significant difference was observed in the first-attempt insertion success rate (relative ratio (RR) 1.06; 95% CI (1.00 to 1.12); p=0.07; high quality) with lower publication bias (p=0.1378). The TSA indicating further trials are required. No significant difference was assessed in the incidence of postoperative pharyngeal pain (RR 1.0; 95% CI (0.14 to 6.90); p=1.0; high quality).

CONCLUSION

Prewarming i-gel laryngeal mask provides higher sealing pressure compared with keeping it at room temperature. But prewarming i-gel laryngeal mask did not increase the first-attempt insertion success rate, nor did it decrease the incidence of postoperative pharyngeal pain.