A comparison of the intubating laryngeal mask airway and the Bonfils intubation fibrescope in patients with predicted difficult airways*

Optical Devices in Tracheal Intubation-State of the Art in 2020

The review article is focused on developments in optical devices, other than laryngoscopes, in airway management and tracheal intubation. It brings information on advantages and limitations in their use, compares different devices, and summarizes benefits in various clinical settings. Supraglottic airway devices may be used as a conduit for fiberscope-guided tracheal intubation mainly as a rescue plan in the scenario of difficult or failed laryngoscopy. Some of these devices offer the possibility of direct endotracheal tube placement. Hybrid devices combine the features of two different intubating tools. Rigid and semi-rigid optical stylets represent another option in airway management. They offer benefits in restricted mouth opening and may be used also for retromolar intubation. Awake flexible fiberoptic intubation has been a gold standard in predicted difficult laryngoscopy for decades. Modern flexible bronchoscopes used in anesthesia and intensive care are disposable devices and contain optical lenses instead of fibers. Endotracheal tubes with an incorporated optics are used mainly in thoracic anesthesia for lung separation. They are available in double-lumen and single-lumen versions. They offer a benefit of direct view to the carina and do not require flexible fiberscope for their correct placement.

Learning Curves for Two Fiberscopes in Simulated Difficult Airway Scenario With Cumulative Sum Method

INTRODUCTION

The aims of this randomized prospective mannequin study were to determine the amount of attempts required for successful intubation using different fiberscopes (Bonfils and SensaScope) by inexperienced anesthesiologists in a difficult airway scenario and to build the associated learning curves.

METHODS

Difficult airway simulation was achieved with tongue edema in mannequin. After approval of volunteers, we asked 15 anesthesiology residents without any experience with fiberscopes to intubate with each device in a random order. Intubation success (endotracheal intubation within 120 seconds), the degree of difficulty of intubation, and reality of simulation using a 10-point scale were recorded. Learning curves were generated with cumulative sum method.

RESULTS

With Bonfils, 13 volunteers were able to pass lower decision boundary with a median number of 26 [95% confidence interval (CI) = 21.4-25.9] attempts, whereas in SensaScope, the same outcome was observed in 10 residents with a median number of attempts of 26 (95% CI = 23.5-32.5). Total success rate was found significantly higher with Bonfils compared with SensaScope (550/600 vs 512/600, respectively, P < 0.001). Intubation with Bonfils was considered as less difficult compared with SensaScope [median = 4 (95% CI = 3.32-4.42) and 6 (95% CI = 4.96-6.64), P = 0.01, respectively]. The reality of the simulation was rated as a median of 5 (95% CI = 4.37-5.8).

CONCLUSIONS

Although a similar number of attempts were required to reach predetermined competency for both fiberscopes, only 10 of residents were able to obtain the targeted success using SensaScope as compared with 13 with Bonfils. Inexperienced residents found intubation via Bonfils less difficult than SensaScope. High individual variability in obtaining competency observed in this study with cumulative sum analysis underlines the importance of defining success a priori to simulation, the need for follow-up of individual progress, and the need to offer adequate trials to achieve competency. Therefore, learning opportunities should be adapted accordingly.

Predictors of Difficult Intubation with the Bonfils Rigid Fiberscope

BACKGROUND

Endotracheal intubation is commonly performed via direct laryngoscopy (DL). However, in certain patients, DL may be difficult or impossible. The Bonfils Rigid Fiberscope® (BRF) is an alternative intubation device, the design of which raises the question of whether factors that predict difficult DL also predict difficult BRF. We undertook this study to determine which demographic, morphologic, and morphometric factors predict difficult intubation with the BRF.

METHODS

Four hundred adult patients scheduled for elective surgery were recruited. Patients were excluded if awake intubation, rapid sequence induction, or induction without neuromuscular blocking agents was planned. Data were recorded, including age, sex, weight, height, American Society of Anesthesiologist classification, history of snoring and sleep apnea, Mallampati class, upper lip bite test score, interincisor, thyromental and sternothyroid distances, manubriomental distances in flexion and extension, neck circumference, maximal neck flexion and extension, neck skinfold thickness at the cricoid cartilage, and Cormack and Lehane grade obtained via DL after paralysis was confirmed. Quality of glottic visualization (good or poor), as well as the number of intubation attempts and time to successful intubation with the BRF, was noted. Univariate analyses were performed to evaluate the association between patient characteristics and time required for intubation. Variables that exhibited a significant correlation were included in a multivariate analysis using a standard least squares model. A P < 0.05 was considered significant.

RESULTS

Glottic visualization with the BRF was good in 396 of 400 (99%) cases. On the first attempt, 390 patients were successfully intubated with the BRF; 6 patients required >1 attempt; 4 patients could not be intubated by using the BRF alone. These 4 patients were intubated by using a combination of DL and BRF (2 patients), DL and a Frova bougie (1 patient), and DL and an endotracheal tube shaped with a semirigid stylet (1 patient). Mean time for successful intubation was 26 ± 13 seconds. Multivariate analysis showed that decreased mouth opening (P = 0.008), increased body mass index (P = 0.011), and higher Cormack and Lehane grade (P = 0.038) predicted longer intubation times, whereas shorter thyromental distance predicted slightly shorter intubation times (P < 0.0001).

CONCLUSIONS

Mouth opening, body mass index, and high Cormack and Lehane grade predict longer intubation times, as with DL. Decreasing thyromental distance predicts slightly shorter intubation times with the BRF, possibly because of a design initially optimized for a pediatric population with receding chins. These findings, along with the high success rate of BRF in this study, and the possibility of further increasing success rates by combining BRF with DL, help define the role of BRF intubation in contemporary airway management.

Awake tracheal intubation in a patient with a supraglottic mass with the Bonfils fibrescope after failed attempts with a flexible fibrescope

Awake intubation with a flexible fibrescope is usually done electively in patients with a known difficult airway. Herein, we describe the case of an elective awake tracheal intubation that was performed on a patient with a large, obstructive supraglottic mass. The intubation was successfully performed using the Bonfils fibrescope after several failed attempts with a flexible fibrescope. This case highlights the usefulness of the Bonfils fibrescope and the limitations of the flexible fibrescope in certain clinical situations.

Nasal intubation: A comprehensive review

Nasal intubation technique was first described in 1902 by Kuhn. The others pioneering the nasal intubation techniques were Macewen, Rosenberg, Meltzer and Auer, and Elsberg. It is the most common method used for giving anesthesia in oral surgeries as it provides a good field for surgeons to operate. The anatomy behind nasal intubation is necessary to know as it gives an idea about the pathway of the endotracheal tube and complications encountered during nasotracheal intubation. Various techniques can be used to intubate the patient by nasal route and all of them have their own associated complications which are discussed in this article. Various complications may arise while doing nasotracheal intubation but a thorough knowledge of the anatomy and physics behind the procedure can help reduce such complications and manage appropriately. It is important for an anesthesiologist to be well versed with the basics of nasotracheal intubation and advances in the techniques. A thorough knowledge of the anatomy and the advent of newer devices have abolished the negative effect of blindness of the procedure.

Bonfils intubation fibrescope: use in simulation-based intubation training for medical students in comparison to MacIntosh laryngoscope

Background

A variety of instruments are used to perform airway management by tracheal intubation. In this study, we compared the MacIntosh balde (MB) laryngoscope with the Bonfils intubation fibrescope as intubation techniques. The aim of this study was to identify the technique (MB or Bonfils) that would allow students in their last year of medical school to perform tracheal intubation faster and with a higher success probability. Data were collected from 150 participants using an airway simulator [‘Laerdal Airway Management Trainer’ (Laerdal Medical AS, Stavanger, Norway)]. The participants were randomly assigned to a sequence of techniques to use. Four consecutive intubation ‘trials’ were performed with each technique. These trials were evaluated for differences in the following categories: the ‘time to successful ventilation‘, ‘success probability’ within 90 s,’time to visualisation’ of the vocal cords (glottis), and ‘quality of visualisation’ according to the Cormack and Lehane score (C&L, grade 1–4). The primary endpoint was the ‘time to successful ventilation‘in the fourth and final trial.

Results

There was no statistically significant difference in the ‘time to successful ventilation’ between the two techniques in trial 4 (‘time to successful ventilation’: median: MB: 16 s, Bonfils: 14 s, p = 0.244). However, the ‘success probability’ within 90 s was higher when using a Macintosh blade than when using a Bonfils (95 vs. 87 %). The glottis could be better visualised when using a Bonfils (C&L score of 1 (best view): MB: 41 %, Bonfils: 93 %), but visualisation was achieved more rapidly when using a Macintosh blade (median: ‘time to visualisation’: MB: 6 s, Bonfils: 8 s, p = 0.003).

Conclusions

The time to ventilation using the MacIntosh blade and Bonfils mainly did to differ, however success probabilities and time to visualisation primary favoured the MacIntosh blade as intubation technique, although the Bonfils seem to have a steeper learning curve. The Bonfils is still a promising intubation technique and might be easier to learn as the MB, at least in a manikin.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-1937-2) contains supplementary material, which is available to authorized users.

A comparison between left molar direct laryngoscopy and the use of a Bonfils intubation fibrescope for tracheal intubation in a simulated difficult airway

BACKGROUND

Tracheal intubation in patients with an immobilized cervical spine can be difficult because of a restricted mouth opening and limited neck movements. Use of the Bonfils intubation fibrescope (BIF) or left molar (LM) laryngoscopy may be suitable options for tracheal intubation in such patients. Intubation adjuncts, such as an endotracheal tube introducer, may improve the overall intubation success rate with the LM approach. Formal studies are currently lacking on the use of LM laryngoscopy with a tube introducer.

METHODS

After Institutional Review Board approval, a cervical collar (to simulate a difficult airway scenario) was placed on 120 prospective elective surgical patients who were randomly assigned to tracheal intubation with a BIF (Group BIF, n = 60) or with tube introducer-assisted LM laryngoscopy with routine optimal external laryngeal manipulation (Group LM, n = 60). The groups were compared for the primary endpoint, total intubation time, as well as for time to glottic view, tube introducer insertion time, intubation success rate, number of intubation attempts, and airway complications.

RESULTS

The mean (SD) total time for intubation was longer in Group LM than in Group BIF [40.4 (14.2) sec vs 33.1 (15.4) sec, respectively; mean difference 7.3 sec; 99% confidence interval (CI) 3.2 to 14.4; P < 0.001] despite less mean (SD) total time required for glottic view [15.4 (10.3) sec vs 23.8 (15.7) sec, respectively; mean difference 8.3 sec; 99% CI 2.3 to 14.7; P < 0.001]. The overall success rate was comparable between groups (95.0% in Group BIF vs 96.6% in Group LM; P = 0.64). Tracheal intubations could not be performed as per protocol in three patients in Group BIF and in two patients in Group LM and were considered as failures. No differences between the groups were found in the incidence of side effects.

CONCLUSION

The tube introducer-assisted LM approach to intubation may be a good alternative to the BIF approach in patients with anticipated and unanticipated difficult airway scenarios.

Bonfils assisted double lumen endobronchial tube placement in an anticipated difficult airway

The role of various airway adjuncts in the management of difficult airway has been described in the literature. Bonfils rigid fiberscope is one of the airway assist devices widely used for endotracheal intubation in the individuals with cervical instability warranting limited neck movements. With our experience in the utilization of Bonfils for single lumen endotracheal tube placement, we are increasingly using for double lumen endobronchial (DLT) intubation as well. We would like to describe our experience in the use of Bonfils for DLT placement and outline the merits and limitations of the other suitable airway assist devices in this report. The double lumen tube has to be modified by decreasing the length of DLT to accommodate the Bonfils fiberscope and this is applicable only in certain type of double lumen tubes for e.g. Bronchocath.

The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.

A randomized controlled comparison of the Bonfils fiberscope and the GlideScope Cobalt AVL video laryngoscope for visualization of the larynx and intubation of the trachea in infants and small children with normal airways

BACKGROUND

The Bonfils fiberscope (BF) used without the assistance of a laryngoscope failed to improve the view of direct laryngoscopy in children with normal airways. We hypothesized that if BF is supported by a laryngoscope--as recommended by its inventor--it can provide comparably good visualization of the glottis as the GlideScope(®) Cobalt AVL video laryngoscope (GS).

METHODS

We included 100 children with normal airways in a randomized controlled trial. The study consisted of assessing the airway by direct laryngoscopy (DL), followed by intubation using either the BF or the GlideScope. Main outcome measures were the quality of visualization of the larynx by the percentage of glottis opening seen (POGO) and the time needed for intubation of the trachea.

RESULTS

Visualization of the larynx (POGO) using the BF was significantly better than with DL (P = 0.016) or with GS (P = 0.001). The DL provided an allover better visualization than GS, although this difference was not significant and solely attributable to children weighing <15 kg. Intubation was successful in all cases with both devices. The time needed for intubation was shorter using the BF (36 ± 8 s) than with the GlideScope (49 ± 12 s, P < 0.001).

CONCLUSION

The Bonfils fiberscope significantly improved the view on the larynx compared with direct laryngoscopy and the GlideScope and enables shorter intubation time than with the GlideScope.

A systematic review of the role of videolaryngoscopy in successful orotracheal intubation

BACKGROUND

The purpose of our study was to organize the literature regarding the efficacy of modern videolaryngoscopes in oral endotracheal intubation, then perform a quality assessment according to recommended external criteria and make recommendations for use.

METHODS

Inclusion criteria included devices with recent studies of human subjects. A total of 980 articles were returned in the initial search and 65 additional items were identified using cited references. After exclusion of articles failing to meet study criteria, 77 articles remained. Data were extracted according to the rate of successful intubation and improvement of glottic view compared with direct laryngoscopy. Studies were classified according to whether they primarily examined subjects with normal airways, possessing risk factors for difficult direct laryngoscopy, or following difficult or failed direct laryngoscopy.

RESULTS

The evidence of efficacy for videolaryngoscopy in the difficult airway is limited. What evidence exists is both randomized prospective and observational in nature, requiring a scheme that evaluates both forms and allows recommendations to be made.

CONCLUSIONS

In patients at higher risk of difficult laryngoscopy we recommend the use of the Airtraq, CTrach, GlideScope, Pentax AWS and V-MAC to achieve successful intubation. In difficult direct laryngoscopy (C&L >/= 3) we cautiously recommend the use of the Airtraq, Bonfils, Bullard, CTrach, GlideScope, and Pentax AWS, by an operator with reasonable prior experience, to achieve successful intubation when used in accordance with the ASA practice guidelines for management of the difficult airway. There is additional evidence to support the use of the Airtraq, Bonfils, CTrach, GlideScope, McGrath, and Pentax AWS following failed intubation via direct laryngoscopy to achieve successful intubation. Future investigation would benefit from precise qualification of the subjects under study, and an improvement in overall methodology to include randomization and blinding.

Comparison of haemodynamic responses to intubation: Flexible fibreoptic bronchoscope versus bonfils rigid intubation endoscope

Background:

The flexible fibreoptic bronchoscope and bonfils rigid intubation endoscope are being widely used for difficult intubations.

Methods:

The haemodynamic response to intubation under general anaesthesia was studied in 60 adult female patients who were intubated using either flexible fibreoptic bronchoscope or bonfils rigid intubation endoscope (30 in each group). Non-invasive blood pressure and heart rate (HR) was recorded before induction of anaesthesia, immediately after induction, at the time of intubation and, thereafter, every minute for the next 5 min. The product of HR and systolic blood pressure (rate pressure product) at every point of time was also calculated.

Statistical Analyses:

Graph pad prism, 5.0 statistical software, independent t test and repeated measure ANOVA test were used.

Results:

Both bonfils rigid intubation endoscope and flexible fibreoptic bronchoscope required a similar time (less than 1 min) for orotracheal intubation. After intubation, there was a significant increase in HR, blood pressure and rate pressure product (P<0.001) in both the groups compared with the baseline and post-induction values. There was no significant difference in HR, blood pressure and rate pressure product at any of the measuring points or in their maximum values during observation between the two groups. The time required for recovery of systolic blood pressure and HR to post-induction value (±10%) was not significantly different between the two groups (more than 2 min).

Conclusion:

In female adults under general anaesthesia, bonfils rigid intubation endoscope and flexible fibreoptic bronchoscope require a similar time for successful orotracheal intubation and cause a similar magnitude of haemodynamic response.

Awake intubation with Bonfil's retromolar fibroscope in a patient with hard and fixed swelling of the right side of the neck and the tonsillar tumor

Bonfil's rigid fibroscope is an instrument used to perform tracheal intubation, proven to be effective both in patients with normal and in those with difficult airways. We use this device in awake intubation in a patient presenting with a large right neck mass and a tonsillar tumor which limited the mouth opening. Also, we describe our technique of insertion of Bonfil's retromolar fibroscope from the right side of the mouth across the tongue.

Performance of emergency physicians utilizing a video-assisted semi-rigid fiberoptic stylet for intubation of a difficult airway in a high-fidelity simulated patient: a pilot study

Background

This study was designed to evaluate emergency physician success and satisfaction using a video-assisted semi-rigid fiberoptic stylet, the Clarus Video System (CVS), during a simulated difficult airway scenario.

Findings

Emergency physicians (EPs) of all levels were first shown a brief slide show and three example videos, and then given 20 min to practice intubating a mannequin using both the CVS and standard direct laryngoscopy (DL). The mannequin was then placed in a c-collar and set to simulate an apneic patient with an edematous tongue and trismus. Each EP was given up to three timed attempts with each technique. They rated their satisfaction with the CVS, usefulness for their practice, and the effectiveness of the tutorial. Direct laryngoscopy had a 65% success rate on the first attempt, 20% on the second, and 15% required three or more. The CVS had a 100% success rate with a single attempt. Average time for independent DL attempts was 43.41 s (SD = ±26.82) and 38.71 s (SD = ±34.14) with CVS. Cumulative attempt times were analyzed and compared (DL = 74.55 ± 68.40 s and CVS = 38.71 ± 34.14 s; p = 0.028). EPs rated their satisfaction with, and usefulness of, the CVS as ≥6 out of 10.

Conclusion

Emergency physicians were able to successfully intubate a simulated difficult airway model on the first attempt 100% of the time. Emergency physicians were satisfied with the CVS and felt that it would be useful in their practice.

Transillumination-assisted orotracheal intubation: a comparison of the Bonfils fibrescope and the lightwand (Trachlight)

BACKGROUND

Because the Bonfils fibrescope has a semi-rigid optical stylet and is similar in shape to a lightwand, we aimed to evaluate and compare the efficacy of transillumination-assisted orotracheal intubation with the Bonfils fibrescope and the Trachlight(TM) lightwand in patients with normal airways.

METHODS

As a preliminary investigation to form a basis for later studies, therefore, we performed a randomized, single-blind study of 300 patients with normal airways to compare the efficiency of Trachlight and transillumination-assisted Bonfils orotracheal intubation in these patients. In both groups, orotracheal intubation was performed using a transillumination technique. The first attempt and overall success rates of tracheal intubation, the times required, and any untoward effects were recorded.

RESULTS

Although the overall success rates were similar for Bonfils and Trachlight intubations (97.3% and 98.7%, respectively), tracheal intubation was successful on the first attempt in 87.3% of patients with the Bonfils fibrescope compared with 95.3% of patients with the Trachlight (P < 0.05). The mean intubation time for the first attempt was 15 ± 5 s with the Bonfils fibrescope and 9 ± 2 s with the Trachlight (P < 0.001). Patients intubated using the Bonfils fibrescope also experienced significantly more sore throat and hoarseness than those intubated using the Trachlight.

CONCLUSIONS

For patients with normal airways, the Trachlight is superior for orotracheal intubation with respect to reliability, rapidity, and safety compared with the Bonfils fibrescope used with the transillumination technique.

Evaluation of the Bonfils intubating fibrescope for predicted difficult intubation in awake patients with ear, nose and throat cancer

BACKGROUND AND OBJECTIVE

Anaesthesiologists are regularly faced with difficult tracheal intubation. The objective of the study was to evaluate the feasibility and tolerability of tracheal intubation with the Bonfils intubating fibrescope in awake adult patients with predicted difficult intubation undergoing cancer surgery in an ear, nose and throat unit.

METHODS

Intubation was performed under local anaesthesia and remifentanil sedation with spontaneous ventilation. The primary endpoint was the proportion of intubations which met the following quality requirements: successful intubation (≤ 2 attempts and duration <180 s) and good tolerability (Fahey scale <2). Secondary endpoints included the operational problems encountered and patients' perception of the procedure immediately and 7 days after the intervention. Using a one-stage Fleming design, 32 patients were required to complete the study. Forty-one eligible adult patients were enrolled.

RESULTS

Between February 2008 and March 2009, the primary endpoint could be evaluated in 33 patients. Quality requirements were met in 26 patients (78.8%) and not met in seven patients (five were intubated with the Bonfils fibrescope and two using another technique). Difficulties were reported in 13 patients (39.4%). Eighty-four percent of the patients had a good or very good perception of the intubation shortly after the procedure, and 91% after 7 days.

CONCLUSION

Tracheal intubation using the Bonfils intubating fibrescope was successful in almost all patients (93.9%). The 78.8% incidence of interventions which met the quality requirements is high in the context of ear, nose and throat cancer and acceptable in current clinical practice. In ear, nose and throat cancer patients who do not require nasopharyngeal intubation and in whom orotracheal intubation is predicted to be difficult, the use of the Bonfils intubating fibrescope is safe, effective and well tolerated.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01070537, URL: http://clinicaltrials.gov/ct2/show/NCT01070537?term=bonfils&rank=2.

Clinical evaluation of the Levitan Optical Stylet

A Levitan Optical Stylet with a modified curve was used in the operating theatre for 301 timed tracheal intubations. Jaw lift was provided manually instead of with a direct laryngoscope. All tracheas except one were intubated successfully (99.7%). Mean (SD) intubation times were 23 (24) s. Three patients (1%) suffered minor trauma. The modified Levitan Optical Stylet can be used without direct laryngoscopy as an effective, rapid and relatively atraumatic tool for intubation, even in difficult airways. It may be appropriate as an alternative or primary intubation technique instead of direct laryngoscopy.

A comparison of bonfils fiberscope-assisted laryngoscopy and standard direct laryngoscopy in simulated difficult pediatric intubation: a manikin study

INTRODUCTION

Difficult airway management in children is challenging. One alternative device to the gold standard of direct laryngoscopy is the STORZ Bonfils fiberscope (Karl Storz Endoscopy, Tuttlingen, Germany), a rigid fiberoptic stylette-like scope with a curved tip. Although results in adults have been encouraging, reports regarding its use in children have been conflicting. We compared the effectiveness of a standard laryngoscope to the Bonfils fiberscope in a simulated difficult infant airway.

METHODS

Ten pediatric anesthesiologists were recruited for this study and asked to perform three sets of tasks. For the first task, each participant intubated an unaltered manikin (SimBaby (TM), Laerdal, Puchheim, Germany) five times using a styletted 3.5 endotracheal tube (ETT) and a Miller 1 blade (group DL-Normal). For the second task, a difficult airway configuration simulating a Cormack-Lehane grade 3B view was created by fixing a Miller-1 blade into position in the manikin using a laboratory stand. Each participant then intubated the manikin five times with a styletted 3.5 ETT using conventional technique but without touching the laryngoscope (group DL-Difficult). In the third task, the manikin was kept in the same difficult airway configuration, and each participant intubated the manikin five times using a 3.5-mm ETT mounted on the Bonfils fiberscope as an adjunct to direct laryngoscopy with the Miller-1 blade (group BF-Difficult). Primary outcomes were time to intubate and success rate.

RESULTS

A total of 150 intubations were performed. Correct ETT placement was achieved in 100% of attempts in group DL-Normal, 90% of attempts in group DL-Difficult and 98% of attempts in BF-Difficult. Time to intubate averaged 14 s (interquartile range 12-16) in group DL-Normal; 12 s (10-15) in group DL-Difficult; and 11 s (10-18) in group BF-Difficult. The percentage of glottic opening seen (POGO score) was 70% (70-80) in group DL-Normal; 0% (0-0) in group DL-Difficult; and 100% (100-100) in group BF-Difficult.

DISCUSSION

The Bonfils fiberscope-assisted laryngoscopy was easier to use and provided a better view of the larynx than simple direct laryngoscopy in the simulated difficult pediatric airway, but intubation success rate and time to intubate were not improved. Further studies of the Bonfils fibrescope as a pediatric airway adjunct are needed.

Improving rigid fiberoptic intubation: a comparison of the Bonfils Intubating Fiberscope with a novel modification

Background

The Bonfils intubating fiberscope has a limited upward tip angle of 40° and requires retromolar entry into the hypopharynx. These factors may make its use less desirable when managing the difficult airway because most anesthesia providers are well versed in midline oral intubation rather than the lateral retromolar approach. The Center for Advanced Technology and Telemedicine at the University of Nebraska Medical Center has developed a novel fiberscope with a more anterior 60° curve to allow for easier midline insertion and intubation. The objective of this work was to evaluate the novel fiberscope, in comparison to the Bonfils intubating fiberscope, in terms of use and function in difficult airway intubation.

Methods

Twenty-two anesthesia providers participated in simulated intubations of a difficult airway mannequin to compare the Bonfils intubating fiberscope with the novel curved Boedeker intubating fiberscope. The intubations were assessed based upon the following variables: recorded Cormack Lehane airway scores, requests for cricoid pressure, time to intubation, number of intubation attempts and success or failure of the procedure.

Results

Participants using the Bonfils fiberscope recorded an average Cormack Lehane (CL) airway score of 1.67 ± 1.02 (median = 1); with the novel fiberscope, the recorded average airway grade improved to 1.18 ± 0.50 (median = 1). The difference in airway scores was not statistically significant (p = 0.34; Fishers Exact Test comparing CL grades 1&2 vs. 3&4). There was, however, a statistically significant difference in intubation success rates between the two devices. With the Bonfils fiberscope, 68% (15/22) of participants were successful in intubation compared to a 100% success rate in intubation with the novel fiberscope (22/22) (p = 0.008). After the intubation trial, the majority of participants (95%) indicated a preference for the novel fiberscope (n = 20).

Conclusions

With this data, we can infer that the novel fiberscope curvature appears to improve or maintain the quality of an intubation attempt (airway score, cricoid pressure requirement, intubation time, number of attempts, placement success). The data indicate that the novel fiberscope offers a superior intubation experience to currently available best practices. The instrument was well received and would be welcomed by most study participants should the device become clinically available in the future.

A comparison of Bonfils intubation fiberscopy and fiberoptic bronchoscopy in difficult airways assisted with direct laryngoscopy

Background

To evaluate the usefulness of Bonfils intubation fiberscope assisted by direct laryngoscopy (BIF-DL) and flexible fiberoptic bronchoscope assisted by direct laryngoscopy (FOB-DL) using video recording in cases of unanticipated difficult intubation with respect to the time required to visualize the vocal cords and place the endotracheal tube. We compared two fiberscopes in patients with authentic difficult airways.

Methods

In this randomized, controlled clinical trial, 40 patients (grade 3 according to grades of difficulty in laryngoscopy), scheduled for surgery under general anesthesia were randomly allocated to BIF-DL group or FOB-DL group. Number of attempts, time required for visualization of the vocal cord (T1) and placement of the endotracheal tube (T2) from insertion of instrument during the last successful attempt, and duration of scope manipulation during all attempts (T_total) were recorded. If intubation failed with one method, the other method was tried; these cases were then excluded. The incidence of sore throat and hoarseness was assessed.

Results

T1, T2, and T_total were significantly shorter in BIF-DL group (T1: 21.9 ± 8.2 sec vs. 80.4 ± 29.9 sec, P < 0.001, T_total: 77.9 ± 41.2 sec vs. 145.5 ± 83.9 sec, P = 0.003). In two cases, it was impossible to intubate with BIF-DL, but the procedure was subsequently successful using fibreoptic bronchoscope.

Conclusions

Intubation of difficult airways can be performed more rapidly with BIF-DL, but sometimes it may not be possible to intubate with the scope.

Rigid fibrescope Bonfils: use in simulated difficult airway by novices

Background

The Bonfils intubation fibrescope is a promising alternative device for securing the airway. We examined the success rate of intubation and the ease of use in standardized simulated difficult airway scenarios by physicians. We compared the Bonfils to a classical laryngoscope with Macintosh blade.

Methods

30 physicians untrained in the use of rigid fibrescopes but experienced in airway management performed endotracheal intubation in an airway manikin (SimMan, Laerdal, Kent, UK) with three different airway conditions. We evaluated the success rate using the Bonfils (Karl Storz, Tuttlingen, Germany) or the Macintosh laryngoscope, the time needed for securing the airway, and subjective rating of both techniques.

Results

In normal airway all intubations were successful using laryngoscope (100%) vs. 82% using the Bonfils (p < 0.05). In the scenario "tongue oedema" success rate using the Macintosh laryngoscope was 67% and 83% using the Bonfils. In the scenario "decreased cervical range of motion with jaw trismus", success rate using the Macintosh laryngoscope was 84% vs. 76%. In difficult airway scenarios time until airway was secured did not differ between the two devices. Use of Bonfils was rated "easier" in both difficult airway scenarios.

Conclusion

The Bonfils can be successfully used by physicians unfamiliar with this technique in an airway manikin. The airway could be secured with at least the same success rate as using a Macintosh laryngoscope in difficult airway scenarios. Use of the Bonfils did not delay intubation in the presence of a difficult airway. These results indicate that intensive special training is advised to use the Bonfils effectively in airway management.

Video and optic laryngoscopy assisted tracheal intubation--the new era

With advances in technology, videoscopy and optic intubation have been gaining popularity particularly in patients with difficult airways or as rescue devices in failed intubation attempts. Their routine use is, however an uncommon occurrence. This review paper will summarise some of those newly developed devices currently available to assist tracheal intubation, their advantages, disadvantages when compared with the conventional laryngoscope and finally, evidence to support their use in both elective and emergency airway management.

Evaluation of the pediatric Bonfils fiberscope for elective endotracheal intubation

BACKGROUND

Difficult airway management in children is a particular challenge for anesthesiologists and pediatricians. This study was designed to evaluate the performance of the recently developed pediatric versions of the Bonfils fiberscope for elective endotracheal intubation during routine surgical procedures.

METHODS

After approval by the institutional review board and written informed consent, 55 children (age 6 +/- 4 years) scheduled for elective minor surgical procedures were enrolled. Nineteen children received atropine before the intubation attempt, while in the remaining 36 children, no antisialogogue was used. For endotracheal tubes up to 3.5 mm internal diameter, a fiberscope with outer diameter (OD) 2 mm, and for larger endotracheal tubes, a fiberscope OD 3.5 mm was used. Time to intubation and failure rate were obtained.

RESULTS

In the 36 children without and the 19 children with atropine pretreatment, the success rate for tracheal intubation on the first attempt was 69%/78% (25/15 patients). 4/3 patients and 2/0 patients were intubated after two and three attempts, respectively, and in 5/1 patients (14%/5%) intubation failed even after three attempts. Time to intubation was median 58/60 s, 25th-75th percentile 35-100/32-110 s, and range 14-377/18-360 s. In both groups, failed intubations were because of the secretions contaminating the optic aperture.

CONCLUSIONS

High failure rate and increased intubation times suggest that the pediatric Bonfils fiberscope has significant drawbacks when used for intubation of normal pediatric airways.