Low skill fibreoptic intubation using i-gel™ and air-Q™ in simulated difficult airways: A randomised study in manikin and in patients

Background:

Fibreoptic intubation via a supraglottic device (SAD) is ‘low skill fibreoptic intubation’ (LSFOI). ‘Standard’ second generation SADs (i-gelTM) have a gastric port. ‘Specialised’ second generation SADs (air-QTM) are designed to facilitate LSFOI and have wider ventilation ports. Our hypothesis was that performance of LSFOI differs between i-gelTM and air-QTM in a manikin with a simulated difficult airway.

Methods:

Our primary outcome was fibreoptic intubation success rate. Our secondary outcomes included SAD insertion and LSFOI times. A difficult airway was simulated by applying a hard cervical collar to a manikin. Anaesthetists performed LSFOI serially using both SADs in a random sequence. In the manikin study, 80 anaesthetists were recruited. To test the robustness of the conclusion from our manikin study, we repeated the study in 22 anaesthetised patients. Patients were fitted with the same cervical collar and randomly allocated to either devices. We used McNemar’s statistical test to analyse our primary outcome of successful intubations and paired nominal data. A Wilcoxon signed-ranks test was used to analyse nonparametric paired data and a Mann–Whitney U test was used for unpaired data analysis where appropriate. A p-value of <0.05 was considered statistically significant.

Results:

In the manikin study, the i-gelTM was superior to the air-QTM for successful tracheal intubation (98.8% vs 83.8%, respectively; p=0.002) and LSFOI times (34.0 s vs 36.0 s, respectively; p=0.012). In the patient study, LSFOI success rates were not significantly different between i-gelTM and air-QTM (100% vs 91.6%, respectively; p=0.545) but intubation times were shorter (52.5 s vs 60.0 s, respectively; p=0.036).

Conclusion:

In conclusion, we obtained LSFOI success rates for the i-gelTM or air-QTM of 98.8% and 83.8% respectively in a manikin; and 100% and 91.6% respectively in patients. It is in fact ‘low skill’ as many participants were successful despite no prior experience with LSFOI. The i-gelTM is superior for LSFOI compared with the air-QTM. This is despite being a ‘standard’ second generation SAD as compared to a ‘specialised’ second generation SAD (air-QTM).

Trial Registration:

The manikin and patient studies were conducted after being approved by the SingHealth Centralised Institutional Review Board (CRB reference number 2014/2039 and 2016/2069, respectively). The patient study was registered at ClinicalTrials.gov (ID: NCT02663843).

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Ambu AuraGain versus intubating laryngeal tube suction as a conduit for endotracheal intubation

Background and Aims

Newly developed supraglottic airway devices (SGAs) are designed to be used both for ventilation and as conduits for endotracheal intubation with standard endotracheal tubes (ETTs). We compared the efficacy of the Ambu AuraGain (AAG) and the newly developed intubating laryngeal tube suction disposable (ILTS-D) as conduits for blind and fiber-optically guided endotracheal intubation in an airway mannequin.

Material and Methods

This is a prospective, randomized, crossover study in an airway mannequin, with two arms: blind ETT insertion by medical students and fiber-optically guided ETT insertion by anesthesiologists. The primary outcome variable was the time to achieve an effective airway through an ETT using AAG and ILTS-D as conduits. Secondary outcome variables were the time to achieve effective supraglottic ventilation and successful exchange with an ETT, and the success rates for blind endotracheal intubation and fiber-optically guided intubation techniques for both SGAs.

Results

Forty participants were recruited to each group. All participants were able to insert both devices successfully on the first attempt. For blind intubation, the success rate for establishing a definitive airway with an ETT using the SGA as a conduit was significantly higher with ILTS-D (82.5%) compared with AAG (20.0%) (P < 0.001). None of the participants were able to successfully complete the exchange of the SGA for the ETT with the AAG. In the fiber optic guided intubation group, the rate of successful exchange was significantly higher with ILTS-D (84.6%) compared with AAG (61.5%) (P = 0.041).

Conclusion

The ILTS-D successfully performs in an airway mannequin with higher success rate and shorter time for blindly establishing an airway with an ETT using the SGA as a conduit, compared with AAG. Further clinical trials are warranted.

Comparison of I-gel for general anesthesia in obese and nonobese patients

Context:

I-gel is a second-generation supraglottic airway device. Despite several studies on i-gel, there are very few studies on the use of i-gel in obese patients.

Aims:

The aim of the study was to compare the clinical performance of i-gel between obese and nonobese patients.

Settings and Design:

Prospective, controlled, nonrandomized, hospital-based study.

Subjects and Methods:

After obtaining informed consent, patients were divided into two groups of 16 patients each: group O consisted of patients with body mass index (BMI) >30 kg/m² and Group C consisted of patients with BMI 18.5–29.9 kg/m². I-gel was inserted after induction of anesthesia and muscle relaxation. Oropharyngeal leak pressure (OLP) (primary outcome variable), leak fraction, time taken to insert the device, ease of insertion, fiberoptic view of glottis through i-gel's airway tube, and adverse effects were recorded.

Statistical Analysis Used:

Data were analyzed using SPSS 20. Continuous, ordinal, and categorical variables were analyzed using students t-test, Mann–Whitney U–test, and Fischer's exact test, respectively.

Results:

OLP was slightly higher in Group O (25.38 ± 4.79 cm H₂O) but was not statistically different than Group C (27.38 ± 4.38 cm H₂O). Other parameters except weight and BMI (which were higher in Group O) were statistically similar in both groups. There was no statistical difference in side effects.

Conclusions:

We concluded that i-gel is as effective in obese patients as in nonobese patients when used for securing the airway for surgical procedures.

Direct and indirect low skill fibre-optic intubation: A randomised crossover manikin study of six supraglottic airway devices

Background and Aims:

Fibre-optic intubation (FOI) through supraglottic airway devices (SADs) is useful in the management of the difficult airway. We compared two methods of FOI through seven SADs in a randomised crossover manikin study to assess each device's performance and discuss implications on SAD selection.

Methods:

Thirty anaesthetsiologists, 15 seniors and 15 juniors, each performed low skill FOI (LSFOI) with seven SADs using both 'direct' and 'indirect' methods. The order of method and device used were randomised. The primary end point was success rate of intubation; secondary end points were time taken for intubation, incidence of difficulties with direct and indirect LSFOI and operator device preference. Statistical analysis was with univariable analysis and comparison of proportions.

Results:

Data from six devices were analysed due to a protocol breach with one SAD. There was no difference in intubation success rate across all SADs and intubation methods. Intubation time was significantly shorter in AmbuAuragain than other SADs and shorter with the direct method of LSFOI than the indirect method (mean difference of 6.9 s, P = 0.027). Ambu Auragain had the least SAD and bronchoscope-related difficulties. Seniors had significantly shorter mean intubation times than juniors by 11.6 s (P = 0.0392). The most preferred SAD for both methods was AmbuAuragain.

Conclusion:

Low skill FOI consistently achieves a high intubation success rate regardless of experience, choice of method, or SAD used. SAD design features may significantly affect the performance of low skill FOI.

Guidelines for the management of tracheal intubation in critically ill adults

These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4^th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.

I-Gel is a suitable alternative to endotracheal tubes in the laparoscopic pneumoperitoneum and trendelenburg position

Background

The use of supraglottic airway devices (SADs) in surgeries with laparoscopic pneumoperitoneum and Trendelenburg (LPT) positioning is controversial due to concerns about insufficient pulmonary ventilation and aspiration. In this prospective, randomized-controlled trial, we evaluated whether the i-gel, a new second generation SAD, provides an effective alternative to an endotracheal tube (ETT) by comparing respiratory parameters and perioperative respiratory complications in non-obese patients.

Methods

In a randomized controlled trial, forty anesthetized patients with ASA I-II were divided into equally sized i-gel and ETT groups. We evaluated the respiratory parameters in the supine and LPT position in comparison between the two groups. The leak fraction was our primary outcome, which was defined as the leak volume divided by the inspired tidal volume. The leak volume was the difference between the inspired and expired tidal volumes. We also monitored pulmonary aspiration and respiratory complications during the perioperative period.

Results

In the LPT position, there were no differences in the leak fraction (median [IQR]) between the i-gel and ETT groups (6.20[3.49] vs 6.38[3.71] %, P = 0.883). In the i-gel group, notably less leakage was observed in the LPT position than in the supine position (median [IQR]: 7.01[3.73] %). This phenomenon was not observed in the ETT group. The rate of postoperative sore throat was also significantly lower in the i-gel group than in the ETT group (3/17 vs 9/11). No vomitus nor any signs associated with aspiration were noted in our patients after extubation in the follow-up prior to discharge.

Conclusions

The i-gel provides a suitable alternative to an ETT for surgeries with LPT positioning in non-obese patients.

Trial registration

Registered at Clinicaltrials.gov NCT02462915, registered on 1 June 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0291-1) contains supplementary material, which is available to authorized users.

The i-gel Supraglottic Airway as a Conduit for Fibreoptic Tracheal Intubation – A Randomized Comparison with the Single-use Intubating Laryngeal Mask Airway and CTrach Laryngeal Mask in Patients with Predicted Difficult Laryngoscopy

Fibreoptic intubation through a supraglottic airway is an alternative plan for airway management in difficult or failed laryngoscopy. The aim of this study was to compare three supraglottic airways as conduits in patients with at least one predictor for difficult laryngoscopy. The i-gel was compared with the single-use intubating laryngeal mask airway (sILMA) and CTrach laryngeal mask in 120 adult patients scheduled for elective surgeries under general anaesthesia using a prospective, randomized and single-blinded design. Primary outcome was success rate of tracheal intubation through the device, while secondary outcomes were times required for device insertion and tracheal tube placement, fibreoptic scores and the incidence of perioperative complications and postoperative complaints. The success rates showed no statistical difference between devices (i-gel 100%, CTrach 97.5%, ILMA 95%). Insertion time was shortest for the i-gel (12.4 s) compared with ILMA (19.3 s) and CTrach (24.4 s). Intubation time was shorter in the i-gel group (29.4 s) in comparison with the CTrach (39.8 s, p<0.05) and sILMA (51.9 s, p<0.001) groups. Best fibreoptic scores were observed also in the i-gel group. In total, 24 patients (20%) presented with difficult laryngoscopy. The i-gel showed significantly shorter times for insertion and fibreoptic intubation than the other two devices in this group. No difference was observed in the incidence of postoperative complaints. The i-gel is a suitable alternative to the sILMA and CTrach for fibrescope-guided tracheal intubation. Shorter insertion and intubation times with the i-gel may provide advantage in case of difficult oxygenation.

A cadaver study comparing three fibreoptic-assisted techniques for converting a supraglottic airway to a cuffed tracheal tube

After rescuing an airway with a supraglottic airway device, a method to convert it to a cuffed tracheal tube is often needed. The best method to do this has never been directly studied. We compared three techniques for conversion of a standard LMA^® Unique airway to a cuffed endotracheal tube using a fibrescope. The primary endpoint was time to intubation, with secondary endpoints of success rate, perceived difficulty and preferred technique. We also investigated the relationship between level of training and prior training and experience with the techniques on the primary outcome. The mean (95% CI) time to intubation using a direct tracheal tube technique of 37 (31-42) s was significantly shorter than either the Aintree intubation catheter technique at 70 (60-80) s, or a guidewire technique at 126 (110-141) s (p < 0.001). Most (13/24) participants rated the tracheal tube as their preferred technique, while 11/24 preferred the Aintree technique. In terms of perceived difficulty, 23/24, 21/24 and 9/24 participants rated the tracheal tube technique, Aintree technique and guidewire technique, respectively, as either very easy or easy. There was no relationship between prior training, prior experience or level of training on time to completion of any of the techniques. We conclude the tracheal tube and Aintree techniques both provide a rapid and easy method for conversion of a supraglottic airway device to a cuffed tracheal tube. The guidewire technique cannot be recommended.

Pressure support ventilation with the I-gel in intensive care unit: case report

BACKGROUND AND OBJECTIVES

The I-gel supraglottic airway has a non-inflatable cuff made from a gel-like thermoplastic elastomer. The use of the I-gel during anesthesia for spontaneously breathing patients or intermittent positive pressure ventilation has been reported. But there are a few published reports about the use of the I-gel with pressure-controlled ventilation.

CONTENTS AND CONCLUSIONS

In this case report we described the use of the I-gel supraglottic airway along 48h in intensive care unit for the management of ventilation in a patient needed mechanic ventilation but in whom tracheal intubation could not be performed.

Overinflation of a King LT Extraglottic Airway Device Mimicking Ludwig's Angina

In this report, we describe the case of a young female with Down syndrome who presented to the anesthesia service after pulseless electrical activity arrest with a King LT(S)-D extraglottic airway device in situ. She had multiple predictors of difficult intubation, including what appeared to be a submental mass consistent with Ludwig's angina. She went on to receive an urgent tracheotomy because of those predictors but had full resolution of the submental mass on removal of the extraglottic airway device, which had been overinflated at the time of insertion. We outline the various techniques to establish a definitive airway with an extraglottic device in place.

i-gel: a new supraglottic device for effective resuscitation of a very low birthweight infant with Cornelia de Lange syndrome

Laryngeal Mask Airway (LMA) has been indicated as an effective device for airway management when face-mask ventilation and intubation have both failed in infants weighing >2000 g or delivered ≥34 weeks of gestation. All previous studies used a classic LMA. The current report describes the first case of a very low birthweight infant (1470 g, <3rd centile; 36(+3)gestational weeks) with micrognathia and palate cleft with Cornelia De Lange syndrome, resuscitated at birth with a new supraglottic airway device, i-gel size-1, positioned by a trainee paediatrician at first attempt. The procedure allowed reaching prompt effective ventilation and oxygenation of the patient, who was stabilised and intubated through i-gel.

A comparison of fibreoptic-guided tracheal intubation through the Ambu ® Aura-i ™, the intubating laryngeal mask airway and the i-gel ™: a manikin study

We compared the Aura-i(™) , intubating laryngeal mask airway and i-gel(™) as conduits for fibreoptic-guided tracheal intubation in a manikin. Thirty anaesthetists each performed two tracheal intubations through each device, a total of 180 intubations. The median (IQR [range]) time to complete the first intubation was 40 (31-50 [15-162]) s, 37 (34-48 [25-75]) s and 28 (22-35 [14-59]) s for the Aura-i, intubating laryngeal mask airway and i-gel, respectively. Tracheal intubation through the i-gel was the quickest (p < 0.01). Resistance to railroading of the tracheal tube over the fibrescope was significantly greater through the Aura-i compared with the intubating laryngeal mask airway and the i-gel (p = 0.001). There were no failures to intubate through the intubating laryngeal mask airway or the i-gel but six intubation attempts through the Aura-i were unsuccessful, in five owing to a railroading failure and in one owing to accidental oesophageal intubation. We conclude that the Aura-i does not perform as well as the intubating laryngeal mask airway or the i-gel as an adjunct for performing fibreoptic-guided tracheal intubation.

Is I-gel airway a better option to endotracheal tube airway for sevoflurane-fentanyl anesthesia during cardiac surgery?

BACKGROUND

Anesthetists used lower doses of fentanyl, successfully with hemodynamic control by titrating volatile anesthetic agents or vasodilators for fast-tracking in cardiac surgery.

HYPOTHESIS

Lower total doses of anesthetics and fentanyl could be required with hemodynamic control by use of supraglottic devices than endotracheal tube (ETT) and helps in fast-tracking.

DESIGN

A prospective randomized observational clinical trial study.

AIMS

The authors compared the utility of I-gel airway with a conventional ETT during the induction and maintenance of anesthesia with sevoflurane and fentanyl in adults undergoing cardiac surgery.

PATIENTS AND METHODS

A total of 49 adult patients underwent cardiac surgery were randomized into two groups according to the airway management: I-gel group (n = 23) and ETT group (n = 26). Doses of fentanyl and hemodynamic parameters (heart rate [HR], mean arterial pressure [MAP] central venous pressure [CVP], pulmonary artery pressure [PAP], and pulmonary capillary wedge pressure [PCWP]) were recorded preoperative, 5 min following tracheal intubation or I-gel airway insertion, after skin incision, after stenotomy, and after weaning off bypass.

RESULTS

None of the patients in the I-gel group required additional doses of fentanyl during the I-gel insertion, compared with 74% of the patients during laryngoscopy and endotracheal insertion in the ETT group, for an average total dose of 22.6 ± 0.6 μg/kg. The MAP and HR did not significantly differ from the baseline values at any point of measurement in either group. Furthermore, CVP, PAP, and PCWP measured during the procedure were significantly lower in I-gel group than ETT group. Extubation required more amount of time in ETT than I- gel group.

CONCLUSION

The I-gel airway is well-tolerated by adult patients undergoing cardiac surgery, and requires lower total doses of anesthetics than endotracheal intubation with hemodynamic control and helps in fast-tracking.

Use of intubation introducers through a supraglottic airway to facilitate tracheal intubation: a brief review

PURPOSE

This article is a narrative review regarding the usage and effectiveness of introducers or catheters to facilitate tracheal intubation through a supraglottic airway (SGA) as an alternative intubation technique in normal and difficult airway management.

SOURCES

Relevant articles were obtained through Medline (1948-July 2011). The articles were subsequently cross-referenced for additional literature, and only articles published in English were included.

PRINCIPAL FINDINGS

In this review, we consider 32 reports using the LMA Classic™, LMA Unique™, LMA ProSeal™, LMA Supreme™, AuraOnce™, and i-gel™ as SGA conduits for intubation. In 13 articles, the use of an Aintree Intubation Catheter was described as an intubation introducer and resulted in high success rates in both elective and emergent situations. Eight studies used a guidewire exchange catheter technique. Although blind intubation using a guidewire resulted in a high failure rate, these studies found that using a bronchoscope improved successful intubation. Ten studies showed that insertion of a gum elastic bougie with a bronchoscope as an intubation introducer has high success rates compared with blind bougie insertion. One article described the use of a small endotracheal tube as an intermediary for tracheal intubation.

CONCLUSIONS

In failed intubation scenarios, supraglottic airways, such as the LMA Classic™ or LMA ProSeal™ can serve as a conduit for tracheal intubation. A number of techniques using introducers or catheters can facilitate the insertion of an adequately sized endotracheal tube, particularly guided by a bronchoscope. Usage of introducers or catheters through a supraglottic airway may be a useful alternative intubation technique in difficult airway management.

Use of the Laryngeal Mask Airway-Aintree Intubating Catheter-fiberoptic bronchoscope technique for difficult intubation

STUDY OBJECTIVE

To determine whether intubation using an Aintree Intubation Catheter (AIC), fiberoptic intubation (FOB), and Laryngeal Mask Airway (LMA) is safe and effective for securing the airway in patients who are difficult to intubate after induction of general anesthesia.

DESIGN

Retrospective review of departmental difficult airway database procedures completed between July 2006 and December 2009.

SETTING

Academic medical center.

MEASUREMENTS AND MAIN RESULTS

During the study period, 128 of 500 patients entered into the difficult airway database underwent the LMA-AIC-FOB technique for intubation. One hundred nineteen (93%) of the 128 patients were successfully intubated by the LMA-AIC-FOB technique, and 9 required an alternate technique. No patient who underwent the LMA-AIC-FOB technique experienced an airway-related mortality or required an emergency surgical airway procedure.

CONCLUSION

The LMA-AIC-FOB technique is safe and effective for patients who are difficult to intubate after induction of anesthesia.

[Placement of a bronchial blocker through the I-gel supraglottic airway device for single-lung ventilation: preliminary study]

To describe the use of the I-gel supraglottic airway device when placing a bronchial blocker for single-lung ventilation, as applied in a preliminary study to explore the feasibility of adopting the technique with appropriate, selected patients undergoing certain thoracic surgery procedures. We used the technique for single-lung ventilation in 25 patients who required isolation of a lung for a variety of thoracic surgical procedures. A bronchial blocker was placed under direct visualization through a fiberoptic bronchoscope and the I-gel supraglottic device. The I-gel mask allowed us to establish a reliable, safe seal of the airway. For an anesthetist with sufficient experience in managing a flexible fiberoptic bronchoscope, it was possible to carry out all procedures without remarkable anesthetic or surgical events. Single-lung ventilation achieved by introducing a bronchial blocker through the I-gel supraglottic device can facilitate safe, effective management of selected patients who must undergo certain thoracic surgery procedures.