The intubating LMA: a comparison of insertion techniques with conventional tracheal tubes

Ease of endotracheal intubation with the conventional polyvinyl chloride endotracheal tube versus wire-reinforced flexometallic tube through the intubating laryngeal mask airway: A comparative study

Background The I-LMA ventilates while providing a port for blind insertion of an endotracheal tube. The ILMA Fastrach is used especially for intubating in a difficult airway scenario. Its accompanying endotracheal tube is not economical nor readily available. In comparison, two alternative endotracheal tubes - polyvinyl chloride and wire-reinforced tubes were used for tracheal intubation through the ILMA.

AIMS AND OBJECTIVES

The aim of our study was to compare the ease of intubation when using conventional PVC tubes versus the wire-reinforced flexometallic tubes with the ILMA-FastrachTM. The number of attempts, time taken and additional maneuvers were noted. Intra-operative hemodynamic changes, post-operative sore throat, bleeding and hoarseness of voice was recorded over a period of 24 hours.

METHODOLOGY

After informed consent, 60 ASA I-II patients undergoing elective surgeries under general anesthesia were allocated to undergo blind intubation with the PVC tube or the wire-reinforced flexometallic tube.

RESULTS

More attempts were required for successful intubation using the wire-reinforced tube than the PVC tube with 76.7% passing in the first attempt in the PVC, and 53.3% passing in the first attempt in the flexometallic group. (P = 0.4). Average time for intubation in the PVC group: 28.24 ± 7.22 seconds. Average time for intubation in the flexometallic tube: 45.8 ± 15.78 sec. Occurrence of post-operative sore throat was 13.3% in the PVC group and 26.6% in the flexometallic group, with minimal hoarseness of voice 3.3% in the PVC group and 10% in the flexometallic group. There was also a slightly higher hemodynamic response in those who were intubated with the flexometallic tube than a PVC tube.

CONCLUSION

Intubating via the ILMA-Fastrach with the PVC tube offered better intubating conditions with regards to lesser time taken, lesser attempts, less manipulation, and less hemodynamic variations as compared to the patients who were intubated using the wire-reinforced tube.

THE HENNEPIN DOUBLE-TUBE TECHNIQUE: A MORE EFFICIENT METHOD OF TRACHEAL INTUBATION THROUGH THE LMA FASTRACH

BACKGROUND

The LMA Fastrach (LMA North America, Inc; hereafter termed the intubating laryngeal mask airway [ILMA]) is an extraglottic device designed to facilitate endotracheal intubation. After the endotracheal tube is placed through the lumen of the ILMA into the trachea, the ILMA is removed, using a proprietary stabilizer rod to hold the tube in place.

DISCUSSION

The traditional method of ILMA removal is not optimized for the critically ill patient. It requires the use of unfamiliar equipment, exposes the patient to a significant period without ventilation, and risks tube dislodgement. We designed a simple technique with a double-endotracheal tube setup that addresses these problems using common equipment, allowing for continuous ventilation, and minimizing the risk of tube dislodgement.

CONCLUSIONS

The traditional method of ILMA removal around an endotracheal tube is not designed for critically ill patients or the physicians taking care of them. This novel technique is designed to improve the usability of the ILMA for physicians and improve airway outcomes for patients.

Intubating Through Supraglottic Airway Devices: A Narrative Review

Implication Statement: Despite the increasing popularity of video laryngoscopes, the supraglottic airway device (SAD) remains a critical airway rescue tool. The SAD provides a conduit for tracheal intubation in failed laryngoscopy. This article aims to help the operator: (1) select an intubating SAD with consistent performance; (2) inform the appropriate SAD-endotracheal tube pairings; and (3) explain various SAD and endotracheal tube maneuvers available to increase chances of successful intubation. Objectives: The first supraglottic airway device (SAD) was introduced more than thirty years ago. Since then, SADs have undergone multiple iterations and improvements. The SAD remains an airway rescue device for ventilation and an intubation conduit on difficult airway algorithms. Data Sources: Several SADs are specifically designed to facilitate tracheal intubation, i.e., “intubating SADs,” while most are “non-intubating SADs.” The two most commonly reported tracheal intubation methods via the SADs are the blind and visualized passage of the endotracheal tube (ETT) preloaded on a fiberoptic scope. Fiberoptic guided tracheal intubation (FOI) via an intubating SAD generally has higher success rates than blind intubations and is thus preferred. However, fiberscopes might not always be readily available, and anesthesiologists should be skilled to successfully intubate blindly through a SAD. Summery: This narrative review describes intubating SAD with consistent performance, appropriate SAD-ETT pairings, and various SAD and ETT maneuvers to increase successful intubation chances.

A comparison of blind intubation with the intubating laryngeal mask FASTRACH™ and the intubating laryngeal mask Ambu Aura-i™ a prospective randomised clinical trial

Background

The intubating laryngeal mask Fastrach™ is considered a gold standard for blind intubation as well as for fibreoptic guided intubation via a laryngeal mask. Recently, a single use version of the mask has been introduced. We compared the Fastrach single use with the new, low-priced single use intubating laryngeal mask Ambu Aura-i™.

We hypothesised that the LMA Ambu Aura-i and the LMA Fastrach are comparable with respect to success rates for mask placement and blind tracheal intubation through the LMA device.

Methods

A prospective, randomised clinical trial. University Hospital Schleswig-Holstein, Campus Kiel, from April 2011 to April 2012.

Eighty patients undergoing general anaesthesia with planned tracheal intubation were randomised and enrolled in the study. Blind intubation was performed with either laryngeal mask using two different tracheal tubes (Rüsch Super Safety Silk™ and LMA ETT™). A crossover-design was performed after an unsuccessful procedure.

Primary outcome measure was the overall success rate of blind intubation. Secondary outcome measures were the time to the first adequate ventilation, a subjective handling score, and a fibreoptic control of placement, as well as the success rate of mask placement, time for mask removal after successful intubation, differences in airway leak pressure, and the incidence of postoperative sore throat and hoarseness.

Results

The success rate of tracheal intubation with the Fastrach for the first and second attempt was significantly better compared with the Ambu Aura-i. Tracheal intubation was also significantly faster (14.1 s. ±4.4 versus 21.3 s. ±9.0; p < 0.01), and the time interval for mask removal after successful intubation was significantly shorter using the Fastrach device (24.0 s. ±8.2 versus 29.4 s. ±7.5; p < 0.001). There were no significant differences between groups regarding the incidence of postoperative sore throat and hoarseness.

Conclusion

Both laryngeal mask devices are suitable for ventilation and oxygenation. Blind intubation remains the domain of the LMA Fastrach, the Ambu Aura-i is not suitable for blind intubation.

Trial registration

Clinicaltrials.gov Identification Number NCT03109678, retrospectively registered on April 12, 2017.

Comparative evaluation of Ambu Aura-i and Fastrach™ intubating laryngeal mask airway for tracheal intubation: A randomized controlled trial

Background and aims:

Ambu Aura-i was compared with Fastrach™ (FT)-laryngeal mask airway (LMA) as a conduit for tracheal intubation.

Material and Methods:

A hundred consenting patients were randomly allocated into two groups of 50 patients each in a prospective randomized study. Standard anesthesia technique was used for all patients and FT-LMA or Ambu Aura-i was selected. After insertion of airway device, the cuff was inflated and ventilation was attempted. Once satisfactory ventilation was achieved, with or without maneuvers, a fiberoptic scoring for glottis view was noted. A polyvinylchloride (PVC) tracheal tube of appropriate size was inserted through the airway device as per procedure. If no resistance was felt while advancing the tracheal tube, it was fully inserted into the device and tracheal tube cuff was inflated. The device was removed and tracheal tube was left in situ. If the first attempt failed during tracheal tube insertion, the recommended maneuvers were used. A maximum of three attempts were allowed for intubation. First attempt for tracheal intubation attempt was a blind, second attempt was made with maneuver. If second attempt of intubation was unsuccessful, fiberoptic-guided intubation was performed as a third attempt. When tracheal intubation was unsuccessful, it was performed by direct laryngoscopy and considered as failed intubation. Rest of the anesthesia management was as per the discretion of attending anesthesiologists. The success rate of device insertion, fiberoptic score of glottis view, tracheal intubation via FT-LMA or Aura-i and time were recorded.

Results:

Both FT-LMA and Aura-i were successfully placed within two attempts. The success rate of blind intubation was 92% in FT-LMA and 76% in Aura-i (P < 0.01). Time taken for tracheal intubation at first attempt was lesser in group FT-LMA and Aura-i, respectively (P < 0.01). Fiberoptic-guided intubation success rate was higher with Aura-i than with FT-LMA.

Conclusions:

FT-LMA had a higher success rate in facilitating blind tracheal intubation compared with Ambu Aura-i.

Supraglottic airway devices as a strategy for unassisted tracheal intubation: A network meta-analysis

We aimed to compare the effectiveness of supraglottic airway devices as a strategy for unassisted tracheal intubation. Accordingly, we searched the OVID-MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, KoreaMed, and Google Scholar databases to identify all relevant randomized controlled trials (RCTs) on supraglottic airway devices as a strategy for tracheal intubation published until May 2017. The primary outcome was the overall success rate of intubation by the intention to treat (ITT) strategy. The secondary outcomes of the study were the overall success rate of tracheal intubation by the per protocol (PP) strategy and the success rate of tracheal intubation at first attempt by ITT and PP. We conducted a network meta-analysis with a mixed-treatment comparison method to combine direct and indirect comparisons among supraglottic airway devices. Of 1396 identified references, 16 RCTs (2014 patients) evaluated unassisted intubation with supraglottic airway devices. Patients were grouped according to the type of device used: LMA-CTrach, LMA-Fastrach, Air-Q, i-gel, CobraPLA, Ambu-Aura, or single-use LMA devices. Based on the surface under the cumulative ranking curve, the three best supraglottic airway devices for use as a strategy for unassisted tracheal intubation were LMA-CTrach (which included video-assisted tracheal tube guidance), single-use LMA-Fastrach, and LMA-Fastrach. LMA-Fastrach showed a higher success rate of intubation than did i-gel, CobraPLA, Air-Q, and Ambu-Aura. However, this study was limited by the small number of eligible RCTs. Therefore, well-designed RCTs performed on large patient populations are required to increase the confidence of the results.

Tracheal intubation through laryngeal mask airway CTrach™ with polyvinyl chloride tube: Comparison between two orientations of the tracheal tube

Background and Aims:

Higher success rate of intubation is observed with the reverse orientation of polyvinyl chloride (PVC) tracheal tube while intubating through laryngeal mask airway (LMA) Fastrach™. It is not clear whether the same is true during intubation through LMA CTrach™ visualizing the process of intubation. The primary aim of this study was to compare the influence of the PVC tracheal tube orientation on the success rate of intubation while intubating through LMA CTrach™.

Material and Methods:

One-hundred and fifty patients belonging to American Society of Anesthesiologists status I–II, undergoing elective surgery under general anesthesia were randomized to either group normal orientation or group reverse orientation. A maximum of 3 intubation attempts within a span of 3 min was allowed in each group before the change over to the other group. If intubation failed with the other orientation of the tube also, then intubation through LMA CTrach™ was abandoned and intubation done by direct laryngoscopy. The success of intubation, time, maneuvers, postoperative sore throat, and hoarseness were recorded.

Results:

Tracheal intubation through LMA CTrach™ with PVC tube was successful in 94.5% of patients in group normal orientation and in 98.6% of patients in group reverse orientation. The first attempt success rate was 75.3% and 86.3% in group normal and group reverse orientation, respectively. The incidence of a sore throat was higher in the group normal orientation than in the reverse orientation (31.8% and 26.5%, respectively).

Conclusions:

Overall success rate of intubation was comparable between the two groups. Though statistically insignificant, the first attempt success rate was higher in group reverse orientation.

Comparison of blind intubation through supraglottic devices and direct laryngoscopy by novices: a simulation manikin study

OBJECTIVE

This study aimed to compare intubation performance between blind intubation through supraglottic airway devices and direct laryngoscopy by novices under manikin simulation. We hypothesized that the intubation time by novices using supraglottic airway devices was superior to that with the Macintosh laryngoscope (MCL).

METHODS

A prospective, randomized crossover study was conducted with 95 participants, to evaluate i-gel, air-Q, LMA Fastrach, and MCL devices. Primary outcomes were the intubation time and the success rate for intubation.

RESULTS

The i-gel showed the shortest insertion and tube passing time among the four devices; the i-gel and air-Q also showed the shortest total intubation time (all P<0.0083; i-gel vs. air-Q, P=0.03). The i-gel and MCL showed the highest cumulative success rate (all P<0.0083; i-gel vs. MCL, P=0.12).

CONCLUSION

Blind intubation through the i-gel showed almost equal intubation performance compared to direct laryngoscopy.

Evaluation of the Effect of Tracheal Tube Orientation on Success of Intubation through Intubating Laryngeal Mask Airway

INTRODUCTION

Polyvinyl Chloride Endotracheal Tube (PVC ETT) can be used as an alternative to Fastrach Silicone Wire-Reinforced Tube (FTST) for intubation through Intubating Laryngeal Mask Airway (ILMA) as the latter is expensive and has low volume high pressure cuff.

AIM

To evaluate the effects of orientation of PVC ETT (normal curve and reverse curve) on the success of intubation through ILMA, haemodynamic response and postoperative sore throat.

MATERIALS AND METHODS

Sixty healthy adult patients of ASA physical status I & II scheduled for elective surgery under general anaesthesia requiring endotracheal intubation were randomly divided into two groups. In Normal (N) group (n=30), the tracheal tube was inserted with its natural curve following the 90° curvature of ILMA. In Reverse (R) group (n=30), the tracheal tube was inserted with its natural curve directed opposite to the curvature of ILMA. The time taken to intubate, number of attempts, and maneuvers required for successful endotracheal intubation along with haemodynamics and oxygen saturation were noted. Postoperative sore throat was evaluated using a Verbal Analogue Scale (VAS) (0-10). Qualitative data was analysed by Chi-Square test and Fisher's exact test. Quantitative data was analysed by unpaired t-test and Mann-Whitney test.

RESULTS

Placement of ILMA was successful in all patients. Total Intubation Time (mean±SD) in Group N was 12.53±1.78 seconds and in Group R was 11.97±1.33 seconds (p>0.05). Tracheal intubation through ILMA was successful in all patients. First attempt success rate in R Group (26 patients, 86.7%) was higher than N Group (22 patients, 73.3%) (p>0.05). Four patients (13.3%) in R Group and 8 patients (26.7%) in N Group required 2nd step of Chandy's maneuver during second attempt for successful intubation. Incidence of sore throat 6 hours postoperatively was statistically significant (median value 2.00 in N Group vs. 0.00 in R Group) between two groups.

CONCLUSION

PVC ETT with reverse orientation increases first attempt success rate of intubation through ILMA with less immediate postoperative laryngeal morbidity.

Intubation Success through I-Gel® and Intubating Laryngeal Mask Airway® Using Flexible Silicone Tubes: A Randomised Noninferiority Trial

Introduction. The study aims to test whether flexible silicone tubes (FST) improve performance and provide similar intubation success through I-Gel as compared to ILMA. Our trial is registered in CTRI and the registration number is "CTRI/2016/06/006997." Methods. One hundred and twenty ASA status I-II patients scheduled for elective surgical procedures needing tracheal intubation were randomised to endotracheal intubation using FST through either I-Gel or ILMA. In the ILMA group (n = 60), intubation was attempted through ILMA using FST and, in the I-Gel group (n = 60), FST was inserted through I-Gel airway. Results. Successful intubation was achieved in 36.67% (95% CI 24.48%-48.86%) on first attempt through I-Gel (n = 22/60) compared to 68.33% (95% CI 56.56%-80.1%) in ILMA (n = 41/60) (p = 0.001). The overall intubation success rate was also lower with I-Gel group [58.3% (95% CI 45.82%-70.78%); n = 35] compared to ILMA [90% (95% CI 82.41%-97.59%); n = 54] (p < 0.001). The number of attempts, ease of intubation, and time to intubation were longer with I-Gel compared to ILMA. There were no differences in the other secondary outcomes. Conclusion. The first pass success rate and overall success of FST through an I-Gel airway were inferior to those of ILMA.

Submental intubation with intubating laryngeal mask airway as conduit: An airway option for oral submucous fibrosis release

The main anesthetic concern with oral submucous fibrosis is progressive restriction of mouth opening due to fibrosis producing difficult airway. Securing airway by nasotracheal intubation and tracheostomy are associated with potential complications. Flexible fiberoscope is not available in all the institutes. Submental intubation using intubating laryngeal mask airway is an acceptable alternative technique in such situations. It also provides an unobstructed surgical field.

[Blind tracheal intubation through two supraglottic devices: i-gel versus Fastrach intubating laryngeal mask airway (ILMA)]

BACKGROUND AND OBJECTIVES

The use of supraglottic devices as a means of rescue in patients difficult to intubate or ventilate has increased in the field of anaesthetics and in emergency medicine. This study is designed to evaluate the success rate of blind intubations using two supraglottic devices, the Fastrach ILMA and the i-gel mask.

PATIENTS AND METHODS

A total of 80 patients (40 per group) were included. After positioning them a leak test was performed, the glottis view was checked with a fibrobronchoscope, and an attempt was made to introduce an endotracheal tube through the device, and the procedure was repeated. Adequate ventilation was evaluated, as well as the grade of fibrobronchoscope view, the success of the intubation, and the complications observed after their use.

RESULTS

There were no differences in the incidence of adequate ventilation with either device. The glottis view (Brimacombe scale) was better with i-gel (77.78% versus 68.42%) at the second attempt, but not on the first. A higher percentage of intubations were achieved with the Fastrach ILMA (70% versus 40%; P=.013). The incidence of throat pain was similar with both devices, but post-operative dysphonia was more frequent with i-gel (20% versus 0; P=.0053).

CONCLUSIONS

Both devices were equally effective in achieving adequate ventilation; however, the Fastrach ILMA enabled a higher number of intubations to be made than i-gel and with a lower incidence of post-operative dysphonia.

Comparison of supraglottic devices i-gel(®) and LMA Fastrach(®) as conduit for endotracheal intubation

Background and Aims:

i-gel^®, a recently introduced supraglottic airway device (SAD) has been claimed to be an efficient supraglottic airway. It can also be used as a conduit for endotracheal intubation. However, LMA Fastrach^® frequently used for this purpose; hence in this randomized study, success rate of blind tracheal intubation through two different SADs i-gel^® and LMA Fastrach^® was evaluated. The complications if any were also studied.

Methods:

A total of 100 patients undergoing elective surgery under general anaesthesia were randomised in two groups comprising of 50 patients each to tracheal intubation using either i-gel (I group) or LMA Fastrach (F group). After induction of anaesthesia SAD was inserted and on achieving adequate ventilation with the device, blind tracheal intubation was attempted through the SAD. Success at first-attempt and overall tracheal intubation success rates were evaluated, and tracheal intubation time was measured. Data were analysed using IBM SPSS Statistics 20.0 software (Statistical Package for Social Sciences by International Business Machines Corporation). P < 0.05 was considered as statistically significant.

Results:

There was no difference in the incidence of adequate ventilation with either of the SAD. The success rate of tracheal intubation in first attempt was 66% in Group I and 74% in Group F, while overall success rate of tracheal intubation was 82% in Group I when compared to 96% in Group F. Time taken for successful tracheal intubation through LMA Fastrach was lesser (20.96 s) when compared to i-gel (24.04 s). Complication rates were statistically similar in both the groups.

Conclusion:

i-gel^® is a better device for rescue ventilation due to its quick insertion but an inferior intubating device in comparison to LMA Fastrach^®.

A comparison of conventional endotracheal tube with silicone wire-reinforced tracheal tube for intubation through intubating laryngeal mask airway

Background:

A specially designed wire-reinforced endotracheal tube — the Fastrach silicone tube (FTST) designed to facilitate endotracheal intubation through intubating laryngeal mask airway (ILMA) are expensive and not readily available. Hence, it is worth considering alternative such as polyvinyl chloride tracheal tube (PVCT), which is disposable, cheap and easily available. The aim of the present study was to compare the clinical performance of FTST with conventional PVCT for tracheal intubation through ILMA.

Methods:

After informed consent, 60 ASA I-II adults with normal airway undergoing elective surgery were randomly allocated to undergo blind tracheal intubation through ILMA with a FTST or conventional PVCT. Overall success rate, ease of insertion, number of attempts for successful intubation, critical incidence during intubation and post-operative sore throat were compared.

Results:

The overall success rate with FTST was 96.63% and 93.33% with PVCT; in addition, the first-attempt success rate was 86.25% with FTST compared to 82.14% with PVCT. The time taken for intubation was 18.6 ± 6.8 s. in FTST group and 22.42 ± 8.5 s. in PVCT group. Incidence of sore throat was 21.42% in PVCT group compared with 6.89% in FTST group.

Conclusion:

Blind tracheal intubation through an ILMA with the conventional PVCT instead of FTST is a feasible alternative in patients with normal airways.

[Blind tracheal intubation with the air-Q(®) (ILA-Cookgas) mask. A comparison with the ILMA-Fastrach™ laryngeal intubation mask]

BACKGROUND AND OBJECTIVES

Supraglottic airway devices are increasingly used in anesthesia and emergency medicine as a rescue for intubation and ventilation. This study was designed to investigate the air-Q(®) supralaryngeal device and compare it with the ILMA-Fastrach™ for airway rescue and intubation.

PATIENTS AND METHODS

The devices were inserted in 80 patients (40 patients in each group) according to manufacturer' instructions. An inspiration pressure of 20cmH2O was applied through a ventilator for checking air leaks. If no air leak was detected, the glottis status was checked using a pediatric fiberoptic bronchoscope, followed by introducing an endotracheal tube through the supraglottic device. If the first attempt was unsuccessful, the device was removed and a second attempt was made in the same way. The primary outcome was the overall success rate for intubation. Other measurements were: successful ventilation, fiberoptic glottis view and adverse events.

RESULTS

Successful first-attempt ventilation was better with the Fastrach™ than with the air-Q(®) (90 vs. 60%, P=.0019) and overall ventilation success (first plus second attempts) was also better with ILMA-Fastrach™ (95 vs. 80%, P=.04). View of the glottis,according to Brimacombe scale, was better with air-Q(®) (84.62 vs. 37.50%, P=.0017) at the second, but not at the first, attempt. There were no differences in the percentage of successful intubations between the 2 devices. The incidence of sore throat was similar with both devices. Two patients in the air-Q(®) group suffered hoarseness and arterial desaturation, but the difference was not statistically significant.

CONCLUSIONS

Both the ILMA-Fastrach™ and the air-Q(®) provided a similar rate of successful intubation, but ILMA-Fastrach™ was better for ventilation. The rate of adverse events was similar with both devices. Because no additional maneuver was used to facilitated intubation, there needs to be further studies to confirm these findings.

Endotracheal intubation through the intubating laryngeal mask airway (LMA-Fastrach™): A randomized study of LMA- Fastrach™ wire-reinforced silicone endotracheal tube versus conventional polyvinyl chloride tracheal tube

Context:

A wire-reinforced silicone tube (LMA-Fastrach™ endotracheal tube) is specially designed for tracheal intubation using intubating laryngeal mask airway (ILMA). However, conventional polyvinyl chloride (PVC) tracheal tubes have also been used with ILMA to achieve tracheal intubation successfully.

Aim:

To evaluate the success of tracheal intubation using the LMA-Fastrach™ tracheal tube versus conventional PVC tracheal tube through ILMA.

Settings and Design:

Two hundred adult ASA physical status I/II patients, scheduled to undergo elective surgery under general anaesthesia requiring intubation, were randomly allocated into two groups.

Methods:

The number of attempts, time taken, and manoeuvres employed to accomplish tracheal intubation were compared using conventional PVC tubes (group I) and LMA-Fastrach™ wire-reinforced silicone tubes (group II). Intraoperative haemodynamic changes and evidence of trauma and postoperative incidence of sore throat and hoarseness, were compared between the groups.

Statistical Analysis:

The data was analyzed using two Student's t test and Chi-square test for demographics and haemodynamic parameters. Mann Whitney U test was used for comparison of time taken for endotracheal tube insertion. Fisher's exact test was used to compare postoperative complications.

Results:

Rate of successful tracheal intubation and haemodynamic variables were comparable between the groups. Time taken for tracheal intubation and manoeuvres required to accomplish successful endotracheal intubation, however, were significantly greater in group I than group II (14.71±6.21 s and 10.04±4.49 s, respectively (P<0.001), and 28% in group I and 3% in group II, respectively (P<0.05)).

Conclusion:

Conventional PVC tube can be safely used for tracheal intubation through the ILMA.

Tracheal intubation through the I-gel™ supraglottic airway versus the LMA Fastrach™: a randomized controlled trial

BACKGROUND

The i-gel™ is a supraglottic airway device not requiring inflation of a cuff for lung ventilation. Its design allows for unobstructed passage of a tracheal tube and previous studies have demonstrated a favorable alignment with the glottic inlet. In this prospective randomized study, we compared the success rate of blind tracheal intubation using the i-gel and the laryngeal mask airway (LMA) Fastrach™.

METHODS

One hundred sixty patients requiring general anesthesia and airway management were randomized to tracheal intubation using the i-gel or the LMA Fastrach. After induction of general anesthesia, the allocated device was inserted and adequate lung ventilation was confirmed. Blind tracheal intubation was then attempted. First attempt and overall tracheal intubation success rates were evaluated and tracheal intubation times were measured.

RESULTS

Eighty patients were recruited in each study group. Successful tracheal intubation was obtained on the first attempt in 69% of patients with the i-gel and 74% of patients with the LMA Fastrach (95% confidence interval [CI] of difference, -9% to 19%, P = 0.60). The overall intubation success rate was lower using the i-gel than it was using the LMA Fastrach (73% vs 91%, 95% CI of difference, 7% to 31%, P < 0.0001).

CONCLUSIONS

On first attempts, successful blind tracheal intubation was obtained at comparable rates using the i-gel and the LMA Fastrach. However, when the first attempt was unsuccessful, subsequent attempts through the i-gel did not significantly increase tracheal intubation success rate. The LMA Fastrach yielded a higher overall intubation success rate.

Effects of tracheal tube orientation on the success of intubation through an intubating laryngeal mask airway: study in Mallampati class 3 or 4 patients

BACKGROUND

We evaluated the effects of conventional tracheal tube orientation on success of intubation through an intubating laryngeal mask airway (ILMA) in Mallampati class 3 or 4 patients.

METHODS

Two hundred adults, ASA I-II, Mallampati class 3 or 4, undergoing elective surgery under general anaesthesia were enrolled. All the patients were randomly allocated to either normal or reverse group based on the orientation of the tracheal tube as it was initially inserted into the ILMA. Tracheal intubation was considered successful, if proper tracheal positioning was attained within three insertion attempts. chi(2) analysis was used to compare categorical variables.

RESULTS

Tracheal intubation through the ILMA was successful in 183 of 200 patients (91.5%): 157 (78.5%) on the first attempt. Seventeen (8.5%) were intubated using direct laryngoscopy. The first-attempt success rate was higher in the reverse than in the normal group (85.0% vs 72.0%, P=0.025), although the overall success rate was similar between the reverse and the normal groups (93.0% vs 90.0%). The incidence of sore throat was comparable in the normal group and the reverse group (22.0% vs 12.0%, NS).

CONCLUSIONS

Overall, tracheal intubation was successful in 91.5% of patients through an ILMA with a conventional tracheal tube in Mallampati class 3 or 4 patients. The first-attempt success rate was higher in the reverse group compared with the normal group, but the overall success rate was similar between the reverse and the normal groups.

Assessment of manoeuvres required for successful blind tracheal intubation through the PAXpress

A PAXpress (Vital Signs Inc., Barnham, UK) airway device was placed in 50 adult ASA grade I and II patients undergoing elective surgery under general anaesthesia. The alignment of the PAXpress to the larynx was scored fibreoptically. The patients were then intubated blindly through the PAXpress and the adjusting manoeuvres required for successful intubation and complications of intubation observed. Insertion of the PAXpress was successful in all patients, and intubation was successful in 42 (84%) patients. Eleven patients were intubated in the neutral position, seven with a flexion manoeuvre and 24 with an extension manoeuvre. Intubation was successful in 17/20, 18/20, 6/8 and 1/2 of patients with a fibreoptic alignment score of 1, 2, 3 and 4, respectively. When the fibreoptic alignment score was between 2 and 4 intubation was achieved predominantly with the extension manoeuvre (20/30, 66%) rather than the flexion manoeuvre (1/30, 3%) or the neutral position (5/30, 16%). Blood staining was observed in 20 patients. We conclude that blind tracheal intubation through PAXpress has a moderately good success rate and a high incidence of mucosal trauma. 'Extension' is the predominant adjusting manoeuvre required for blind tracheal intubation, especially when the alignment of the PAXpress to the larynx is poor.

Comparison of intubating laryngeal mask airway and Bullard laryngoscope for oro-tracheal intubation in adult patients with simulated limitation of cervical movements

BACKGROUND

Intubation of a patient with limited cervical spine movement or in whom movement of the cervical spine is not desirable is always a challenge even to the most experienced anaesthesiologist. The intubating laryngeal mask airway (ILMA) and the Bullard laryngoscope (BL) are two instruments recommended for endotracheal intubation of such patients. We compared their utility and safety in patients with simulated cervical spine immobility using manual inline stabilization (MILS).

METHODS

Sixty-two patients, ASA I or II, between 18 and 65 yr, were enrolled in this prospective and randomized study. They were randomly allocated to one of the two groups: Group BL (Bullard laryngoscope) and Group IL (Intubating Laryngeal Mask Airway). The patients were intubated orally using either equipment after induction of general anaesthesia.

RESULTS

The success rate for intubation in the first or second attempt was higher in Group BL [90.32% (28/31)] than in Group IL [74.2% (23/31)] but was not statistically significant. The number of attempts taken for intubation and the total time to intubate were similar between the groups. Trauma as evidenced by blood on endotracheal tube or sore throat was similar in both groups.

CONCLUSIONS

Both the BL and the ILMA are useful equipment in intubating patients with limitation of cervical movements. Although not statistically significant, the BL may provide a higher success rate of intubation when compared with the ILMA.

Conventional tracheal tubes for intubation through the intubating laryngeal mask airway

The laryngeal mask airway (LMA)-Fastrach silicone wire-reinforced tracheal tube (FTST) was specially designed for tracheal intubation through the intubating LMA (ILMA). However, conventional tracheal tubes have been successfully used to accomplish tracheal intubation. We designed this study to evaluate the success rate of blind tracheal intubation through the ILMA by using the FTST, the Rusch polyvinyl chloride tube (PVCT), and the Rusch latex armored tube (LAT). One-hundred-fifty healthy adults of ASA physical status I and II who were undergoing elective surgery under general anesthesia were randomly allocated into three groups. FTST (n=50), prewarmed PVCT (n=50), and LAT (n=50) were used for tracheal intubation. Ease of tracheal intubation was assessed by the time taken, the number of attempts, and the number of maneuvers required for success. In addition, numbers of failed intubation attempts and times taken for ILMA removal were also recorded. After surgery, the incidence of trauma, sore throat, and hoarseness was noted. Significantly more frequent success in tracheal intubation was achieved with the PVCT and FTST (96%) compared with the LAT (82%) (P <0.05). Tracheal intubation on the first attempt was similar with the PVCT and FTST (86%) and was significantly more frequent than with the LAT (52%) (P <0.05). Esophageal placement was significantly more frequent with the LAT (29.7%) when compared with the PVCT and FTST (1.8% and 7.4%, respectively) (P <0.05). The authors conclude that a prewarmed PVCT can be used as successfully as the FTST for blind tracheal intubation through the ILMA, whereas the LAT is associated with more frequent failure and esophageal intubation.

PVC tracheal tubes exert forces and pressures seven to ten times higher than silicone or armoured tracheal tubes--an in vitro study

PURPOSE

Many types of tracheal tubes (TT) including silicone, polyvinylchloride (PVC) and armoured have been used for blind tracheal intubation (TI) via the intubating laryngeal mask airway (ILMA) and may cause trauma to the airway. We examined the maximal in vitro forces and pressures exerted by the tip of various TT as it exits the ILMA.

METHODS

Silicone, PVC and armoured TT were studied. A #5 ILMA was secured on a wooden platform. With the use of a Harvard pump, force was applied to push the TT through the ILMA at 0.34 cm*sec(-1). Forces exerted to push the TT and forces exerted by the TT tips on distal objects were calculated using proximal and distal pressure manometres. The areas of contact between the distal TT tips and the distal objects were measured by planimetry of an imprint. The final pressures exerted by the TT tips on a fixed distal object were calculated by dividing the forces exerted by the areas of contact.

RESULTS

When compared to silicone and armoured TT, PVC TT exerted seven to ten times higher forces and pressures on distal objects. (P < 0.05). Heating PVC TT and inserting PVC TT with reverse curvature to the ILMA did not decrease the forces and pressures exerted by the distal tip.

CONCLUSION

The high forces and pressures exerted by PVC TT may theoretically contribute to increased morbidity to patients' airway and esophagus. Caution should be exercised before attempting blind TI via the ILMA with a PVC TT.

Intubating laryngeal mask airway

The Intubating Laryngeal Mask Airway (ILMA) was introduced into clinical practice in 1997 following numerous clinical trials involving 1110 patients. The success rate of blind intubation via the device after two attempts is 88% in "routine" cases. Successful intubation in a variety of difficult airway scenarios, including awake intubation, has been described, with the overall success rate in the 377 patients reported being approximately 98%. The use of the ILMA by the novice operator has also been investigated with conflicting reports as to its suitability for emergency intubation in this setting. Blind versus visualized intubation techniques have also been investigated. These techniques may provide some benefits in improved safety and success rates, although the evidence is not definitive. The use of a visualizing technique is recommended, especially whilst experience with intubation via the ILMA is being gained. The risk of oesophageal intubation is reported as 5% and one death has been described secondary to the complications of oesophageal perforation during blind intubation. Morbidity described with the use of the ILMA includes sore throat, hoarse voice and epiglottic oedema. Haemodynamic changes associated with intubation via the ILMA are of minimal clinical consequence. The ILMA is a valuable adjunct to the airway management armamentarium, especially in cases of difficult airway management. Success with the device is more likely if the head of the patient is maintained in the neutral position, when the operator has practised at least 20 previous insertions and when the accompanying lubricated armoured tube is used.

The intubating laryngeal mask airway in severe ankylosing spondylitis

PURPOSE

To evaluate the use of inhalational induction followed by intubation through the intubating laryngeal mask (ILM) for patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.

METHODS

Nine patients undergoing a total of 11 procedures were enrolled in the study. Fentanyl 2 microg*kg(-1), midazolam 0.035 mg*kg(-1) and sevoflurane in oxygen 100% were used for induction. The ILM was inserted when the end-tidal sevoflurane concentration reached 3%. After an effective airway was established, atracurium 0.5 mg*kg(-1) was given. A polyvinyl chloride tube in the reversed position using a blind technique was used to intubate the trachea.

RESULTS

The ILM provided an effective airway on 11/11 occasions at the first attempt. Intubation was successful at the first attempt on 7/11 occasions, at the second attempt on 2/11 and at the third attempt in 1/11. Intubation failed in one patient. The mean (range) minimal oxygen saturation was 99.4% (97-100%). There were no problems with ILM removal.

CONCLUSION

Inhalational induction followed by ILM insertion and blind intubation is a reasonable option in patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.