Three-dimensional cervical spine movement during intubation using the Macintosh and Bullard™ laryngoscopes, the Bonfils fibrescope and the Intubating Laryngeal Mask Airway

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.

Cervical Spine Motion During Tracheal Intubation Using an Optiscope Versus the McGrath Videolaryngoscope in Patients With Simulated Cervical Immobilization: A Prospective Randomized Crossover Study

BACKGROUND

In patients with an unstable cervical spine, maintenance of cervical immobilization during tracheal intubation is important. In McGrath videolaryngoscopic intubation, lifting of the blade to raise the epiglottis is needed to visualize the glottis, but in patients with an unstable cervical spine, this can cause cervical spine movement. By contrast, the Optiscope, a rigid video-stylet, does not require raising of the epiglottis during tracheal intubation. We therefore hypothesized that the Optiscope would produce less cervical spine movement than the McGrath videolaryngoscope during tracheal intubation. The aim of this study was to compare the Optiscope with the McGrath videolaryngoscope with respect to cervical spine motion during intubation in patients with simulated cervical immobilization.

METHODS

The primary outcome of the study was the extent of cervical spine motion at the occiput-C1, C1-C2, and C2-C5 segments. In this randomized crossover study, the cervical spine angle was measured before and during tracheal intubation using either the Optiscope or the McGrath videolaryngoscope in 21 patients with simulated cervical immobilization. Cervical spine motion was defined as the change in angle at each cervical segment during tracheal intubation.

RESULTS

There was significantly less cervical spine motion at the occiput-C1 segment using the Optiscope rather than the McGrath videolaryngoscope (mean [98.33% CI]: 4.7° [2.4-7.0] vs 10.4° [8.1-12.7]; mean difference [98.33% CI]: -5.7° [-7.5 to -3.9]). There were also fewer cervical spinal motions at the C1-C2 and C2-C5 segments using the Optiscope (mean difference versus the McGrath videolaryngoscope [98.33% CI]: -2.4° [-3.7 to -1.2]) and -3.7° [-5.9 to -1.4], respectively).

CONCLUSIONS

The Optiscope produces less cervical spine motion than the McGrath videolaryngoscope during tracheal intubation of patients with simulated cervical immobilization.

Awake supraglottic airway guided flexible bronchoscopic intubation in patients with anticipated difficult airways: a case series and narrative review

Awake intubation is indicated in difficult airways if attempts at securing the airway after induction of general anesthesia may lead to harm due to potential difficulties or failure in those attempts. Conventional awake flexible bronchoscopic intubation is performed via the nasal, or less commonly, oral route. Awake oral flexible bronchoscopic intubation (FBI) via a supraglottic airway device (SAD) is a less common technique; we refer to this as ‘supraglottic airway guided’ FBI (SAGFBI). We describe ten cases with anticipated difficult airways in which awake SAGFBI was performed. After sedation and adequate airway topicalization, an Ambu Auragain^TM SAD was inserted. A flexible bronchoscope, preloaded with a tracheal tube, was then inserted through the SAD. Finally, the tracheal tube was railroaded over the bronchoscope, through the SAD and into the trachea. The bronchoscope and the SAD were carefully removed, whilst keeping the tracheal tube in-situ. The technique was successful and well tolerated by all patients, and associated complications were rare. It also offered the advantages of performing an ‘awake test insertion’ of the SAD, an ‘awake look’ at the periglottic region, and an ‘awake test ventilation.’ In certain patients, awake SAGFBI offers advantages over conventional awake FBI or awake videolaryngoscopy. More research is required to evaluate its success and failure rates, and identify associated complications. Its place in difficult airway algorithms may then be further established.

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.

A comparison of the transillumination-assisted technique versus midline approach technique in novices: a prospective randomized controlled trial about the Bonfils intubation fiberscope

Background

The present study aimed to compare the safety and efficacy for novices to conduct intubation with the Bonfils intubation fiberscope (BIF) using the transillumination-assisted or midline approach technique in patients with normal airways.

Methods

In this prospective randomized control study, 10 trainees were assigned to the transillumination-assisted technique group (T group) or the midline approach technique group (R group). Each trainee was required to conduct intubation in 50 patients. The primary outcome was intubation time. The secondary outcomes were success rate (%), number of attempts, and complications.

Results

Among the cases of successful intubation, the intubation time was not significantly different between the two groups (P > 0.05). The overall success rate of intubation was not significantly different between the two groups (P > 0.05). The intubation success rates at the first, second, and third attempts as well as the average intubation times were similar between the two groups (P > 0.05), but in patients receiving successful intubation at the second attempt, the intubation time was longer in the T group (P = 0.0006). The incidences of dry throat, sore throat, and hoarseness were higher in the T group (all P < 0.05).

Conclusions

For patients with a normal airway, the transillumination-assisted technique was unlikely to increase the success rate of intubation with the BIF compared with the midline approach technique, but led to more complications.

Trial registration

ChiCTR-INR-16009967, retrospectively registered on November 22, 2016

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0322-6) contains supplementary material, which is available to authorized users.

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.

Upper airway modifications in head extension during development

BACKGROUND

One of the requirements of laryngoscopy is to determine which head position will result in optimal visualization. Our hypothesis was that parameters derived from magnetic resonance imaging (MRI) can help quantify the effect of age on airway modifications due to head extension during development.

METHOD

In children undergoing planned MRI, additional sequences on the upper airways were performed: one in a near-neutral position, the other with the head extended at 35°. The axis of the face, the pharynx, the larynx, the trachea, and the line of glottic visualization were determined. The following angles were calculated: the Visu-Lar angle, formed by the line of glottic visualization and the laryngeal axis, and the Phar-Lar angle, formed by the pharyngeal and laryngeal axes.

RESULTS

One hundred and fifty-five patients (1 to 222 months of age [25-145] months) were included and 54% were under general anaesthesia. Age had no effect on the variation in the Visu-Lar angle, which diminished as a function of head extension, nor on the variation in the Phar-Lar angle, which was minimal in the neutral position. During extension, anatomical axes rotated similarly, and the visualization axis rotated the most, followed by the pharyngeal and laryngeal axes. These results were not correlated with general anaesthesia.

CONCLUSION

Regardless of age, head extension diminished the Visu-Lar angle, and increased the Phar-Lar angle. This study supports that, as in adults, head extension is probably the key factor for good visualization conditions during laryngoscopy on children, but clinical data is needed to confirm this result.

Airway Management with Cervical Spine Immobilisation: A Comparison between the Macintosh Laryngoscope, Truview Evo2, and Totaltrack VLM Used by Novices--A Manikin Study

Airway management in patients with suspected cervical spine injury plays an important role in the pathway of care of trauma patients. The aim of this study was to evaluate three different airway devices during intubation of a patient with reduced cervical spine mobility. Forty students of the third year of emergency medicine studies participated in the study (F = 26, M = 14). The time required to obtain a view of the entry to the larynx and successful ventilation time were recorded. Cormack-Lehane laryngoscopic view and damage to the incisors were also assessed. All three airway devices were used by each student (a novice) and they were randomly chosen. The mean time required to obtain the entry-to-the-larynx view was the shortest for the Macintosh laryngoscope 13.4 s (±2.14). Truview Evo2 had the shortest successful ventilation time 35.7 s (±9.27). The best view of the entry to the larynx was obtained by the Totaltrack VLM device. The Truview Evo2 and Totaltrack VLM may be an alternative to the classic Macintosh laryngoscope for intubation of trauma patients with suspected injury to the cervical spine. The use of new devices enables achieving better laryngoscopic view as well as minimising incisor damage during intubation.

Efficacy of the Airway Scope (Pentax-AWS) for training in pediatric intubation

BACKGROUND

The aim of this study was to evaluate the efficacy of the Airway Scope (AWS) in the training of residents in pediatric intubation using high-performance simulators.

METHODS

A total of 51 residents were recruited. Baby SIM is a high-performance simulator with a built-in physiological program that reduces SpO2 if it stops breathing and increases SpO2 if assisted ventilation is provided using a bag mask. Therefore, real-life situations can be simulated with this program. Trial 1: after respiration of Baby SIM was stopped, intubation was initiated. If the intubation time was too long, a built-in physiological program led to desaturation. The intubation time and frequency of SpO2 <90% were compared between the Miller laryngoscope and the AWS. Trial 2: an ALS Baby, which is more difficult to intubate than Baby SIM, was used in comparison of intubation time and frequency of failure to intubate within 60 s between the two laryngoscopes. Mann-Whitney and chi-squared tests were used for statistical analysis.

RESULTS

Intubation time was significantly shorter using the AWS than the Miller laryngoscope in both trials. Furthermore, desaturation occurred significantly less frequently with the AWS than the Miller laryngoscope in trial 1. The frequency of intubation failure within 60 s was also significantly lower for the AWS than the Miller laryngoscope in trial 2.

CONCLUSION

The inclusion of both direct laryngoscopy and the AWS in pediatric resident programs might give pediatricians the option of using a safer and more reliable intubation method for children.

Neurological deterioration during intubation in cervical spine disorders

Anaesthesiologists are often involved in the management of patients with cervical spine disorders. Airway management is often implicated in the deterioration of spinal cord function. Most evidence on neurological deterioration resulting from intubation is from case reports which suggest only association, but not causation. Most anaesthesiologists and surgeons probably believe that the risk of spinal cord injury (SCI) during intubation is largely due to mechanical compression produced by movement of the cervical spine. But it is questionable that the small and brief deformations produced during intubation can produce SCI. Difficult intubation, more frequently encountered in patients with cervical spine disorders, is likely to produce greater movement of spine. Several alternative intubation techniques are shown to improve ease and success, and reduce cervical spine movement but their role in limiting SCI is not studied. The current opinion is that most neurological injuries during anaesthesia are the result of prolonged deformation, impaired perfusion of the cord, or both. To prevent further neurological injury to the spinal cord and preserve spinal cord function, minimizing movement during intubation and positioning for surgery are essential. The features that diagnose laryngoscopy induced SCI are myelopathy present on recovery, short period of unconsciousness, autonomic disturbances following laryngoscopy, cranio-cervical junction disease or gross instability below C3. It is difficult to accept or refute the claim that neurological deterioration was induced by intubation. Hence, a record of adequate care at laryngoscopy and also perioperative period are important in the event of later medico-legal proceedings.

Intubation biomechanics: laryngoscope force and cervical spine motion during intubation with Macintosh and Airtraq laryngoscopes

INTRODUCTION

Laryngoscopy and endotracheal intubation in the presence of cervical spine instability may put patients at risk of cervical cord injury. Nevertheless, the biomechanics of intubation (cervical spine motion as a function of applied force) have not been characterized. This study characterized and compared the relationship between laryngoscope force and cervical spine motion using two laryngoscopes hypothesized to differ in force.

METHODS

Fourteen adults undergoing elective surgery were intubated twice (Macintosh, Airtraq). During each intubation, laryngoscope force, cervical spine motion, and glottic view were recorded. Force and motion were referenced to a preintubation baseline (stage 1) and were characterized at three stages: stage 2 (laryngoscope introduction); stage 3 (best glottic view); and stage 4 (endotracheal tube in trachea).

RESULTS

Maximal force and motion occurred at stage 3 and differed between the Macintosh and Airtraq: (1) force: 48.8 ± 15.8 versus 10.4 ± 2.8 N, respectively, P = 0.0001; (2) occiput-C5 extension: 29.5 ± 8.5 versus 19.1 ± 8.7 degrees, respectively, P = 0.0023. Between stages 2 and 3, the motion/force ratio differed between Macintosh and Airtraq: 0.5 ± 0.2 versus 2.0 ± 1.4 degrees/N, respectively; P = 0.0006.

DISCUSSION

The relationship between laryngoscope force and cervical spine motion is: (1) nonlinear and (2) differs between laryngoscopes. Differences between laryngoscopes in motion/force relationships are likely due to: (1) laryngoscope-specific cervical extension needed for intubation, (2) laryngoscope-specific airway displacement/deformation needed for intubation, and (3) cervical spine and airway tissue viscoelastic properties. Cervical spine motion during endotracheal intubation is not directly proportional to force. Low-force laryngoscopes cannot be assumed to result in proportionally low cervical spine motion.

[Cervical spine instability: point of view of the anesthesiologist]

The experience in airway management permits the anesthesiologist to participate in cases of cervical spine instability in the operating room when the patient is subjected to surgical procedures, or in cases of difficulty to access or keep the airway open in emergencies. This article reviews the epidemiology, definition, etiology, diagnostic criteria, methods of approach to airway management, and current recommendations on handling cervical instability in different scenarios. There is no approach to the airway that ensures complete immobility of the cervical spine, but there are methods that are better adapted to specific contexts; at the end, the reader will be able to identify the virtues and defects of the various options that the anesthesiologists have to address the airway in cases of cervical instability.

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.

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.

Complications in spinal deformity surgery: issues unrelated directly to intraoperative technical skills

STUDY DESIGN

Literature review of complications unrelated directly to surgical skills involved in spinal deformity surgery.

OBJECTIVE

Highlight complications associated with perioperative issues.

SUMMARY OF BACKGROUND DATA

Complications can arise from mundane events that arise during the operative experience, but are not directly related to surgical skills.

METHODS

Literature reviews that touches on the more common potential complication events that do not involve direct surgical expertise.

RESULTS

The topics of positioning, nutrition, blood loss, comorbidities, OR time, and pulmonary and GI concerns are discussed as basics that could derail a surgical outcome even with an otherwise uneventful surgical technique. The need for vigilance is stressed and the nuances of understanding these are discussed.

CONCLUSION

Mundane events can derail a perfectly executed surgical undertaking. Attention to detail, team work, close monitoring, and checklist type focus will help to improve, focus, and avoid these preventable complications that have nothing to do with direct surgical skills.

Comparison of Flexiblade and Macintosh laryngoscopes: cervical extension angles during orotracheal intubation

SUMMARY

The Flexiblade(TM) is a new laryngoscope with a flexible blade, a handle and a lever, allowing gradual flexion over the distal half of the blade. In this study, we aimed to compare cervical vertebral movements during tracheal intubation with the Flexiblade and Macintosh laryngoscope in 32 patients undergoing elective surgery requiring general anaesthesia (n = 16 per group). Fluoroscopic images of cervical movement were captured before, during and after intubation and evaluated by a radiologist. C1-C2 cervical vertebral movement was significantly reduced during the intubation in the Flexiblade group (p < 0.0001). C2-C3 cervical movement was similar in both groups (p = 0.81). No significant differences were noted in success rates for intubation, oxygen saturation levels, haemodynamic variables or intubation-related injury. The decreased extension angle between C1-C2 during Flexiblade laryngoscopy compared with Macintosh laryngoscopy may be an advantage where neurological damage with cervical movement is a concern.

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.

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.

The Parker Flex-Tip™ tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster

BACKGROUND

The Bullard laryngoscope can be useful in management of difficult airway. When the endotracheal tube is advanced over the original Bullard laryngoscope stylet, the endotracheal tube sometimes makes contact with structures around the vocal cords, especially the right arytenoids. A similar problem also occurs with flexible fibreoptic intubation and it has been shown that use of the Parker Flex-Tip tube usually resolves the problem. In this study we tested our hypothesis that use of the Parker Flex-Tip tube might improve endotracheal tube passage with the Bullard laryngoscope.

METHODS

Forty patients scheduled for elective anaesthesia were randomly assigned into group ST (standard tube) or Group PT (Parker Flex-Tip tube). The time taken to achieve successful endotracheal tube placement after obtaining the best laryngeal view, the number of attempts at intubation and the incidences of successful intubation at first attempt and of re-direction of the Bullard laryngoscope during intubation were recorded. Unpaired t-test and chi2-test were employed and P < 0.05 was considered significant.

RESULTS

Use of the Parker Flex-Tip tube reduced the time required for successful endotracheal tube placement after the best laryngeal view was obtained from 14 +/- 6 to 6 +/- 2 s (P < 0.01). It also reduced the incidence of requirement for re-direction of the Bullard laryngoscope during intubation from 10/19 to 1/19 (P < 0.01). The incidence of successful intubation at the first attempt (18/19 vs. 15/19) was higher in the PT group but the difference was not statistically significant.

CONCLUSIONS

During intubation with the Bullard laryngoscope, use of the Parker Flex-Tip tube is associated with more rapid success and a lower incidence of re-direction of the Bullard laryngoscope during endotracheal intubation when compared to a standard endotracheal tube.

Prehospital emergency endotracheal intubation using the Bonfils intubation fiberscope

Among all prehospital emergency intubations, difficulties occur in 7-10%. Furthermore, intubation conditions often worsen when the cervical spine is immobilized in trauma patients. We report on six patients in whom the Bonfils intubation fiberscope, a reusable, rigid fiberoptic device, was used for emergency endotracheal intubation in the field. Three of these patients had an anticipated or unanticipated difficult airway: two trauma patients with immobilized cervical spine and one patient in cardiac arrest in whom direct laryngoscopy failed twice. Endotracheal intubation with the Bonfils intubation fiberscope was successful in all cases in the first attempt. The Bonfils intubation fiberscope therefore demonstrated its value as an additional airway management device in both emergency and prehospital settings.