Cervical spine motion: a fluoroscopic comparison during intubation with lighted stylet, GlideScope, and Macintosh laryngoscope

Adoption of video laryngoscopy in Massachusetts emergency departments

BACKGROUND

Previous research suggests that video laryngoscopy may be superior to direct laryngoscopy.

OBJECTIVES

We sought to determine the proportion of Massachusetts emergency departments (EDs) that have adopted video laryngoscopy, the characteristics of user and non-user EDs, the reasons why non-users do not use video laryngoscopy, and how the adoption of video laryngoscopy compares to typical technology adoption life cycles.

METHODS

Surveys were mailed to directors of all non-federal EDs in Massachusetts (n=74) in early 2009. Non-responders received repeat mailings and were then contacted via telephone or e-mail.

RESULTS

Sixty-three of 74 (85%) EDs responded and 43% had adopted video laryngoscopy. EDs with video laryngoscopy had a higher median annual visit volume than EDs without video laryngoscopy (48,000 vs. 36,500, p=0.04), but had similar mean intubations per week (4.5 vs. 4.4, p=0.97) and mean surgical airways per year (0.7 vs. 1.1, p=0.19). Half of the EDs affiliated with emergency medicine residency programs had video laryngoscopy available. Among EDs with video laryngoscopy, the technology had been available for>5 years in 4% (1/27), 1-5 years in 44% (12/27), and<1 year in 52% (14/27). Although EDs not using video laryngoscopy did not do so primarily because it was too expensive (69% [25/36]), video laryngoscopy adoption has still progressed more rapidly than predicted by the typical technology adoption timeline.

CONCLUSION

Video laryngoscopy has been adopted by 43% of Massachusetts EDs; results were similar in academic institutions. Cost is the primary barrier to adoption for non-user EDs, but adoption is progressing more rapidly than expected for a new technology.

Advances in prehospital trauma care

Prehospital trauma care developed over the last decades parallel in many countries. Most of the prehospital emergency medical systems relied on input or experiences from military medicine and were often modeled after the existing military procedures. Some systems were initially developed with the trauma patient in mind, while other systems were tailored for medical, especially cardiovascular, emergencies. The key components to successful prehospital trauma care are the well-known ABCs of trauma care: Airway, Breathing, Circulation. Establishing and securing the airway, ventilation, fluid resuscitation, and in addition, the quick transport to the best-suited trauma center represent the pillars of trauma care in the field. While ABC in trauma care has neither been challenged nor changed, new techniques, tools and procedures have been developed to make it easier for the prehospital provider to achieve these goals in the prehospital setting and thus improve the outcome of trauma patients.

Comparison of the laryngeal view during intubation using Airtraq and Macintosh laryngoscopes in patients with cervical spine immobilization and mouth opening limitation

BACKGROUND

For patients suspicious of cervical spine injury, a Philadelphia cervical collar is usually applied. Application of Philadelphia cervical collar may cause difficult airway. The aim of this study was to evaluate the laryngeal view and the success rate at first intubation attempt of the Airtraq and conventional laryngoscopy in patients with simulated cervical spine injury after application of a Philadelphia cervical collar.

METHODS

Anesthesia was induced with propofol, remifentanil, and rocuronium. After a Philadelphia cervical collar applied, patients were randomly assigned to tracheal intubation with an Airtraq (Group A, n = 25) or with conventional laryngoscopy (Group L, n = 25). Measurements included intubation time, success rate of first intubation attempt, number of intubation attempts, and percentage of glottic opening (POGO) score. Mean blood pressure and heart rate were also recorded at baseline, just before and after intubation.

RESULTS

The success rate of the first attempt in Group A (96%) was significantly greater than with the Group L (40%). POGO score was significantly greater in Group A (84 ± 20%) than in Group L (6 ± 11%). The duration of successful intubation at first tracheal intubation attempt and hemodynamic changes were not significantly different between the two groups.

CONCLUSIONS

The Airtraq offers a better laryngeal view and higher success rate at first intubation attempt in patients who are applied with a Philadelphia cervical collar due to suspicion of cervical spine injury.

Advances in laryngoscopy: rigid indirect laryngoscopy

There is a growing body of evidence to support the use of rigid indirect laryngoscopy or 'video' laryngoscopy for tracheal intubation. We summarise some of the key issues, comparing rigid indirect laryngoscopy with direct conventional laryngoscopy.

Pre-hospital care management of a potential spinal cord injured patient: a systematic review of the literature and evidence-based guidelines

An interdisciplinary expert panel of medical and surgical specialists involved in the management of patients with potential spinal cord injuries (SCI) was assembled. Four key questions were created that were of significant interest. These were: (1) what is the optimal type and duration of pre-hospital spinal immobilization in patients with acute SCI?; (2) during airway manipulation in the pre-hospital setting, what is the ideal method of spinal immobilization?; (3) what is the impact of pre-hospital transport time to definitive care on the outcomes of patients with acute spinal cord injury?; and (4) what is the role of pre-hospital care providers in cervical spine clearance and immobilization? A systematic review utilizing multiple databases was performed to determine the current evidence about the specific questions, and each article was independently reviewed and assessed by two reviewers based on inclusion and exclusion criteria. Guidelines were then created related to the questions by a national Canadian expert panel using the Delphi method for reviewing the evidence-based guidelines about each question. Recommendations about the key questions included: the pre-hospital immobilization of patients using a cervical collar, head immobilization, and a spinal board; utilization of padded boards or inflatable bean bag boards to reduce pressure; transfer of patients off of spine boards as soon as feasible, including transfer of patients off spinal boards while awaiting transfer from one hospital institution to another hospital center for definitive care; inclusion of manual in-line cervical spine traction for airway management in patients requiring intubation in the pre-hospital setting; transport of patients with acute traumatic SCI to the definitive hospital center for care within 24 h of injury; and training of emergency medical personnel in the pre-hospital setting to apply criteria to clear patients of cervical spinal injuries, and immobilize patients suspected of having cervical spinal injury.

Distortion of anterior airway anatomy during laryngoscopy with the GlideScope videolaryngoscope

PURPOSE

A non-line-of-sight view is expected to cause less movement of the anterior airway anatomy and cervical spine during laryngeal visualization. Reduced distortion of anterior airway anatomy during laryngoscopy with the GlideScope videolaryngoscope (GVL), compared with the Macintosh laryngoscope, could explain the relatively easier nasotracheal intubation with the GVL. The purpose of this radiographic study was to compare the degree of anterior airway distortion and cervical spine movement during laryngoscopy with the GVL and the conventional Macintosh laryngoscope.

METHODS

Twenty patients requiring general anesthesia and tracheal intubation were studied. Each patient underwent laryngoscopy using the first-generation GVL and a direct laryngoscope with a Macintosh blade. During each laryngoscopy, a radiograph was taken when the best view of the larynx was obtained. Independent radiologists with subspeciality training in musculoskeletal imaging evaluated anterior airway distortion and cervical spine movement.

RESULTS

The distance between the epiglottis and the posterior pharyngeal wall during the GlideScope procedure was 21% less than that during the Macintosh laryngoscopy (P < 0.05). Anterior deviations of the vertebral bodies from baseline were 27, 32, 36, and 39% less at the atlas, C2, C3, and C4 vertebrae, respectively, during the GlideScope procedure than those measured during Macintosh laryngoscopy (P < 0.01). Cervical extension between the occiput and C4 during the GlideScope procedure was 23% less than that during Macintosh laryngoscopy (P < 0.05).

CONCLUSION

Both anterior airway distortion and cervical spine movement during laryngeal visualization were less with the GVL than with the Macintosh laryngoscope.

Patient- and operator-related factors associated with successful Glidescope intubations: a prospective observational study in 742 patients

The Glidescope Video Laryngoscope (Glidescope, Verathon Medical, Bothell, WA, U.S.A.) is a relatively new intubating device. It has been proposed to be useful for securing both routine airways and those where direct laryngoscopy may be difficult. In this prospective observational study, data for 742 intubations using the Glidescope were collected to investigate whether four factors are associated with successful tracheal intubation at first attempt using the Glidescope: previous Glidescope experience, previous direct laryngoscopy experience, level of anaesthesia training and clinical airway assessment. The likelihood of successful tracheal intubation at first attempt using the Glidescope increased with increasing previous Glidescope experience. Similarly, success was more likely in airways that were assessed as normal compared with those where direct laryngoscopies were either predicted or known to be difficult. Subgroup analysis indicated 83% first attempt success by 'experienced' Glidescope users in patients with documented difficult direct laryngoscopies. This supports its use as an adjunct device for management of airways where direct laryngoscopies prove difficult. With regard to the level of anaesthesia training, only medical students were more likely to fail with the Glidescope. Success was not associated with previous experience in direct laryngoscopy. The lack of association with direct laryngoscopy experience and level of anaesthesia training (beyond student level) suggests that expertise with traditional airway tools is not necessary to become proficient with the Glidescope.

Evaluation of the GlideScope for tracheal intubation in patients with cervical spine immobilisation by a semi-rigid collar

Application of cervical collars may reduce cervical spine movements but render tracheal intubation with a standard laryngoscope difficult if not impossible. We hypothesised that despite the presence of a Philadelphia Patriot cervical collar and with the patient's head taped to the trolley, tracheal intubation would be possible in 50 adult patients using the GlideScope and its dedicated stylet. Laryngoscopy was attempted using a Macintosh laryngoscope with a size 4 blade, and the modified Cormack-Lehane grade was scored. Subsequently, laryngoscopy with the GlideScope was graded and followed by tracheal intubation. All patients' tracheas were successfully intubated with the GlideScope. The median (IQR) intubation time was 50 s (43-61 s). The modified Cormack-Lehane grade was 3 or 4 at direct laryngoscopy. It was significantly reduced with the GlideScope (p < 0.0001), reaching grade 2a in most patients. Tracheal intubation in patients wearing a semi-rigid collar and having their head taped to the trolley is possible with the help of the GlideScope.

Learning curves of the Glidescope, the McGrath and the Airtraq laryngoscopes: a manikin study

BACKGROUND AND OBJECTIVE

Several video and optical laryngoscopes have been developed but few have been compared in terms of their learning curves and efficacy. Using a manikin with normal airways we compared the Glidescope, the McGrath, the Airtraq and the Macintosh laryngoscopes.

METHODS

Sixty anaesthetists (20 staff, 20 residents and 20 nurses) participated in the study. All subjects were novice with the new devices. They intubated a Laerdal SimMan manikin (with normal airway) five times in a row with all laryngoscopes. The sequence of use of the devices was randomized. Before using a device, a presentation and a demonstration were provided. Outcome measures were: duration of intubation attempt, modified Cormack grades, dental trauma and difficulty of use.

RESULTS

The Airtraq had the most favourable learning curve and mirrored the Macintosh after two intubation attempts. The Glidescope and McGrath had steep learning curves but, after five attempts, differences persisted when compared with the Macintosh and Airtraq. Time taken to visualize the glottis was similar but time taken to position the endotracheal tube was shorter for the Airtraq when compared with the Glidescope and McGrath. Indirect laryngoscopes seemed to have advantages over the Macintosh blade in terms of laryngeal exposure and potential dental trauma.

CONCLUSIONS

In a 'normal airway' model, intubation skills with the new devices appeared to be rapidly mastered. The three indirect laryngoscopes provided a better glottic exposure than the Macintosh. The Airtraq displayed the most favourable learning curve, probably reflecting differences in the techniques of endotracheal tube placement: guiding channel versus steering technique.

Utilization of a Glidescope videolaryngoscope for orotracheal intubations in different emergency airway management settings

OBJECTIVE

To describe the initial experience of a group of emergency department (ED) physicians, utilizing a Glidescope videolaryngoscope (GVL) for orotracheal intubations in the ED.

METHODOLOGY

A 6-month, single center, prospective observational study from 19 Feb 2007 to 18 Aug 2007 was conducted on all orotracheal intubations, which involved utilization of the original GVL in different emergency airway management scenarios.

RESULTS

Overall success of GVL intubation was 15 out of 21 (71.4%) cases. The GVL was able to provide at least Cormack-Lehane grade I or II laryngoscopy views in all cases. All the operators highlighted difficulty in angulating and maneuvering the endotracheal tube for insertion through the glottis as the primary difficulty encountered.

CONCLUSION

We found the GVL to be an effective device in our ED's emergency airway control repertoire. Its role in the anticipated difficult airway in the ED will need further studies.

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.

Cervical spine motion during flexible bronchoscopy compared with the Lo-Pro GlideScope

BACKGROUND

The most appropriate device for tracheal intubation in patients with potential cervical spine injury remains controversial. We hypothesized that the Lo-Pro GlideScope (LP-G) videolaryngoscope would not cause significantly greater cervical spine movement than fibreoptic bronchoscopy even in the non-immobilized spine.

METHODS

Twenty-eight healthy adults requiring intubation for radiographic procedures were randomized to either the LP-G or the flexible bronchoscope (FB) devices. Continuous fluoroscopy was used to assess cervical spine movement during tracheal intubation. The point of maximum movement was compared with baseline for change in angulation between Occiput (Occ)-C1, Occ-C2, Occ-C4, Occ-C5, C1-2, C2-4, and C4-5. Measurements were made by two independent observers. The change in angulation was also measured for tongue pull and jaw thrust, manoeuvres for enlarging the pharyngeal space, before FB intubation.

RESULTS

LP-G resulted in greater cervical extension compared with FB for every angle calculated, statistically significant between Occ-C1 (P<0.05), Occ-C2 (P<0.05), and Occ-C4 (P<0.01). Tongue pull resulted in significantly less cervical spine motion than FB intubation at Occ-C1, Occ-C2, Occ-C4, and Occ-C5 (P<0.05). When jaw thrust was added to tongue pull, there was a tendency for greater movement than FB intubation at Occ-C1, Occ-C2, and Occ-C3. This was statistically significant at Occ-C1 and Occ-C3 (P<0.05) for one of the two observers.

CONCLUSIONS

During intubation under general anaesthesia, LP-G resulted in greater cervical movement than FB when no cervical immobilization was used in adults without cervical disease. Airway manoeuvres performed before FB, especially jaw thrust, also resulted in cervical spine movement.

Predictors of difficult intubation in patients with cervical spine limitations

BACKGROUND

Cervical spine function is of paramount importance to the management of the airway. What has not been reported in the literature is a systematic analysis of airway management in patients with cervical spine limitation (CSL) compared with their normal counterparts or a predictive model of difficult intubation (DI) in patients with CSL.

METHODS

We reviewed the electronic charts of 14,053 patients and identified those with CSL based on the preoperative airway evaluation. We then compared various airway parameters in patients with CSL to those without CSL and further assessed risk factors for DI in patients with CSL. We develop a predictive model on the basis of multivariate analysis of such risk factors.

RESULTS

Of the cohort studied, 1145 or 8.1% of patients were documented as having some form of CSL, with an average age of 60. In the <60 population, CSL was associated with a statistically significant increase in difficult and impossible mask ventilation, difficult laryngoscopy, and DI. In the population > or =60 years old, CSL was associated with a statistically significant increase in difficult laryngoscopy and DI. There were no significant differences in mask ventilation between normal and CSL patients in the population > or =60. Multivariate modeling revealed age > or =48, Mallampati 3 or 4, and thyromental distance <6 cm as independent preoperative risk factors of DI in patients with CSL. A predictive model is developed on the basis of these findings.

CONCLUSIONS

Limitations of cervical spine mobility are relatively common and increase the incidence of difficulty throughout the spectrum of airway management. DI should be anticipated in CSL patients who are > or =48 years old, have a Mallampati class 3 or 4, and a thyromental distance of <6 cm.

Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus GlideScope videolaryngoscopy

BACKGROUND

The optimal tracheal intubation technique for patients with potential cervical (C) spine injury remains controversial. Using continuous cinefluoroscopy, we conducted a prospective study comparing C-spine movement during intubation using direct laryngoscopy (DL) or GlideScope videolaryngoscopy (GVL), with uninterrupted manual in-line stabilization of the head by an assistant.

METHODS

Twenty patients without C-spine pathology were studied. After induction of general anesthesia with neuromuscular blockade, both DL and GVL were performed on every patient in random order. Cinefluoroscopic images of C-spine movement during GVL and DL were acquired and divided into four stages: a baseline image before airway manipulation, glottic visualization, insertion of the endotracheal tube into the glottis, and tracheal intubation. Peak segmental motion from the occiput to C5 was measured offline for each patient and each stage, averages were calculated, and movements induced by each instrument were compared using a two-way ANOVA. Also studied were the proportion of patients with occiput-C1 rotation exceeding 10, 15, or 20 degrees, and the quality of glottic visualization.

RESULTS

No significant difference was found between DL and GVL regarding average segmental spine movement at any level (P values between 0.22 and 0.70). During both techniques, motion was mainly an extension concentrated in the rostral C-spine and occurred predominantly during glottic visualization. The proportion of patients with occiput-C1 extension of more than 10, 15, or 20 degrees was not significantly different. Glottic visualization was significantly better with GVL compared with DL.

CONCLUSION

During intubation under general anesthesia with neuromuscular blockade and manual in-line stabilization, the use of GVL produced better glottic visualization, but did not significantly decrease movement of the nonpathologic C-spine when compared with DL.

The GlideScope-specific rigid stylet and standard malleable stylet are equally effective for GlideScope use

PURPOSE

The GlideScope videolaryngoscope usually provides excellent glottic visualization, but directing an endotracheal tube (ETT) through the vocal cords can be challenging. The goal of the study was to compare the dedicated GlideScope-specific rigid stylet to the standard malleable stylet, assessed by time to intubation (TTI).

METHODS

Eighty patients requiring orotracheal intubation for elective surgery were randomly allocated to either the GlideScope rigid stylet (GRS) or a standard malleable stylet to facilitate intubation using the GlideScope. Time to intubation was recorded by blinded assessors; operators were blinded until after laryngoscopy. The operator assessed the ease of intubation using a visual analogue scale (VAS). The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were documented.

RESULTS

The median TTI was 42.7 sec (inter-quartile range (IQR) 38.9-56.7) for the GRS group compared to 39.9 sec (IQR 34.1-48.2) for the control group (P=0.07). The median VAS score for ease of intubation was 20 (IQR 12.0-33.0) for the GRS group compared to 18 (IQR 9.5-29.5) for the control group (P=0.21). There was no significant difference in TTI or VAS between stylets. The overall incidence of a Cormack-Lehane grade I or II glottic view was 98%.

CONCLUSIONS

In a group of experienced operators using the GlideScope, the dedicated GRS and the standard malleable ETT stylet are equally effective in facilitating endotracheal intubation.

Considerations for airway management for cervical spine surgery in adults

Surgery on the cervical spine runs the gamut from minor interventions done in a minimally invasive fashion on a short-stay or ambulatory basis, to major surgical undertakings of a high-risk, high-threat nature done to stabilize a degraded skeletal structure to preserve and protect neural elements. Planning for optimum airway management and anesthesia care is facilitated by an appreciation of the disease processes that affect the cervical spine and their biomechanical implications and an understanding of the imaging and operative techniques used to evaluate and treat these conditions. This article provides background information and evidence to allow the anesthesia practitioner to develop a conceptual framework within which to develop strategies for care when a patient is presented for surgery on the cervical spine.

Airway Management in Trauma: An Update

This article reviews the more recent theoretic and practical information that pertains to airway management in the trauma setting. This is followed by a presentation of the newer airway devices that may be advantageous in the management of the airway in trauma as well as a discussion of other devices, techniques, or maneuvers that are useful in the trauma setting but may be underused. Each clinician needs to be knowledgeable about the various airway options and then, based on one's own particular skills and resources, construct an airway management algorithm that works best for him or her. Each clinician needs to be knowledgeable about the various airway options, and then, based on the clinician's particular skills and resources, construct an airway management algorithm that works best.

Case series: the McGrath videolaryngoscope--an initial clinical evaluation

PURPOSE

To document tracheal intubation success rates and airway instrumentation times using the newly designed McGrath videolaryngoscope.

METHODS

We prospectively recorded factors associated with difficult tracheal intubation, factors causing actual difficulty in tracheal intubation, as well as complications arising from use of the new McGrath videolaryngoscope in a series of adult patients with normal preoperative airway examinations. All patients were undergoing scheduled or elective surgery. In the first 75 patients (phase I), experience with airway instrumentation was documented, while in the second 75 patients (phase II), the time required to obtain an optimal view of the larynx was recorded, as well as the time to complete tracheal intubation.

RESULTS

Ninety-eight percent of all tracheal intubations were successful using the McGrath videolaryngoscope. Cormack and Lehane grade I views were obtained in 143 patients (95%) and grade II views were achieved in six (4%). In phase II, the median time required to obtain an adequate view was 6.3 sec [interquartile range 4.7-8.7 (range 2-26.3)], and to complete tracheal intubation was 24.7 sec [18.5-34.4 (11.4-286)]. Fortynine (65%) of the tracheal intubations were completed within 30 sec, and 72 (96%) were completed within one minute. No complications were encountered in any patient.

CONCLUSIONS

The McGrath videolaryngoscope is an effective aid to airway management in patients with normal airways, based upon intubation success rates and the ability to rapidly secure the airway. Its potential advantages of convenience and portability warrant further evaluation in comparison with other airway devices and in patients with difficult airways.

Cervical spine motion: a fluoroscopic comparison of Shikani Optical Stylet® vs Macintosh laryngoscope

PURPOSE

The optimal technique to manage the airway in patients presenting with a potential or documented cervical spine (C-spine) injury remains unresolved. Using fluoroscopic video assessment, C-spine motion during laryngoscopy with a Shikani Optical Stylet (SOS) was compared to C-spine motion during intubation using a Macintosh blade.

METHODS

Twenty-four healthy surgical patients gave written consent to participate in a crossover randomized controlled trial; all patients were subjected to both Macintosh and Shikani laryngoscopy with manual inline stabilization following induction of anesthesia. The C-spine motion was examined at four areas: the occiput-C1 junction, C1-C2 junction, C2-C5 motion segment, and C5-thoracic motion segment. The time required for laryngoscopy was also measured (duration > 120 sec was deemed a failure of the laryngoscopy technique).

RESULTS

On average, C-spine motion was 52% less (P < 0.02) at three of the motion segments studied, occiput-C1, C2-C5, and C5-thoracic when comparing SOS vs Macintosh laryngoscopy. There was no difference between techniques at the C1-C2 segment. Laryngoscopy with SOS (28 +/- 17 sec) took longer than with Macintosh blade (17 +/- 7 sec), P < 0.01. There were two failures out of 23 using the SOS, vs none with the Macintosh blade.

CONCLUSION

For patients in whom C-spine movement is undesirable, use of the SOS may limit neck movement, while modestly increasing the time required to intubate, and/or the risk of procedure failure.

Effect of stylet angulation and endotracheal tube camber on time to intubation with the GlideScope

PURPOSE

The GlideScope videolaryngoscope usually provides excellent glottic visualization, but directing an endotracheal tube (ETT) through the vocal cords is sometimes difficult. The goal of the study was to determine which of two ETT angles (60 degrees vs 90 degrees ) and cambers (forward vs reverse) was better, as determined by time to intubation (TTI).

METHODS

Two hundred patients requiring orotracheal intubation for elective surgery were randomly allocated to one of four groups: A) 90 degrees angle, forward camber; B) 90 degrees angle, reverse camber; C) 60 degrees angle, forward camber; D) 60 degrees angle, reverse camber. Time to intubation was assessed by a blinded observer. Operators were blinded until the point of intubation. A visual analogue scale (VAS) assessed the ease of intubation. The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were recorded.

RESULTS

The angle of the ETT had an impact on TTI but camber did not. The 90 degrees angle demonstrated a 13% faster TTI than the 60 degrees angle (47.1 +/- 21.2 sec vs 54.4 +/- 28.2 sec, P=0.042), and it resulted in easier intubation (VAS 16.4 +/- 14.2 mm vs 27.3 +/- 23.5 mm, P=0.0001). The overall incidence of a grade 1 or 2 Cormack-Lehane glottic view was 99%.

CONCLUSIONS

In a heterogeneous group of operators and patients intubated with the GlideScope, a 90 degrees ETT angle provided the best result and should be the initial configuration. The camber of the ETT does not affect the time to intubation.