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

Comparison between the Trachway video intubating stylet and Macintosh laryngoscope in four simulated difficult tracheal intubations: A manikin study

OBJECTIVES

It remains to be determined whether the TVI-4000 Trachway video intubating (TVI) stylet (Markstein Sichtec Medical Corp, Taichung, Taiwan), an airway device for novices, improves airway management practice by experienced anesthesiologists. The aim of this study was to evaluate the feasibility of using the TVI stylet in difficult tracheal intubation situations compared with that of using the Macintosh laryngoscope on an airway manikin.

MATERIALS AND METHODS

Ten anesthesiologists (with 3-21 years' experience), including three senior residents, participated. We compared tracheal intubation in four airway scenarios: normal airway, tongue edema, cervical spine immobilization, and tongue edema combined with cervical spine immobilization. The time of tracheal intubation (TTI), success rate, and perceived difficulty of intubation for each scenario were compared and analyzed.

RESULTS

The TTI was significantly shorter in both the tongue edema and combined scenarios with the TVI stylet compared with the Macintosh laryngoscope (21.60 ± 1.45 seconds vs. 24.07 ± 1.58 seconds and 23.73 ± 2.05 seconds vs. 26.6 ± 2.77 seconds, respectively). Success rates for both devices were 100%. Concomitantly, participants rated using the TVI stylet in these two scenarios as being less difficult.

CONCLUSION

The learning time for tracheal intubation using the TVI stylet in difficult airway scenarios was short. Use of the TVI stylet was easier and required a shorter TTI for tracheal intubation in the tongue edema and combined scenarios.

Cervical Spine Movement and Ease of Intubation Using Truview or McCoy Laryngoscope in Difficult Intubation

STUDY DESIGN

Prospective, observational, analytical, randomized control trial.

OBJECTIVE

To compare cervical spine movement for best laryngoscopic view and ease of intubation using Truview or McCoy laryngoscope in anticipated difficult intubation.

SUMMARY OF BACKGROUND DATA

The addition of modified laryngoscope blade to the anesthesiologist's armamentarium adds flexibility and improves the skill of the anesthetist, which benefits the patients.

METHODS

One hundred patients of American Society of Anesthesiologists status I and II with predicted difficult intubation score ≥5 were divided into two groups: Group A (n = 50): intubation done with McCoy laryngoscope and Group B (n = 50): intubation done with Truview laryngoscope and compared for the ease of intubation using intubation difficulty scale (IDS), cervical spine movement, and hemodynamic alterations.

RESULTS

The total IDS determining the ease of tracheal intubation was better in Group B than Group A. On comparing the variables of IDS score, there was no difference between the two groups except 14 (28%) patients in Group A required application of external laryngeal pressure, whereas only five (10%) patients had this difficulty in Group B. It was seen that craniocervical extension was significantly less (2.5 times) in Group B as compared to Group A.

CONCLUSION

In anticipated difficult intubation, Truview improves the laryngeal view, causes less movement at cervical spine, which could be more helpful in patients with restricted neck mobility, and has lesser complications.

LEVEL OF EVIDENCE

2.

Relevance of radiological and clinical measurements in predicting difficult intubation using light wand (Surch-lite™) in adult patients

Objective

To determine the correlation between anatomical features of the upper airway (evaluated via computed tomography imaging) and the ease of light wand-assisted endotracheal intubation in patients undergoing ear, nose and throat surgery under general anaesthesia.

Methods

Mallampati class, laryngoscopic grade, thyromental distance, neck circumference, body mass index, mouth opening and upper lip bite class were assessed. Epiglottis length and angle, tongue size and narrowest pharyngeal distance were determined using computed tomography imaging. Intubation success rate, time to successful intubation (intubating time) and postoperative throat symptoms were documented.

Results

Of 152 patients, 148 (97.4%) were successfully intubated on the first attempt (mean intubating time 11.5 ± 6.7 s). Intubating time was positively correlated with laryngoscopic grade and body mass index in both male and female patients, and Mallampati class and neck circumference in male patients. Epiglottis length was positively correlated with intubating time.

Conclusions

Ease of intubation was influenced by epiglottis length. Radiological evaluation may be useful for preoperative assessment of patients undergoing endotracheal intubation with light wand.

Efficacy of pulmonary rehabilitation using cervical range of motion exercise in stroke patients with tracheostomy tubes

[Purpose] In this study, stroke patients who were intubated with tracheostomy tubes performed cervical range of motion exercises, and changes in their pulmonary and coughing functions were examined. [Subjects and Methods] Twelve stroke patients who were intubated with tracheostomy tubes participated in the study. The subjects were randomly assigned to either the control group (n=6), which did not perform cervical range of motion exercises, or the experimental group (n=6), which did perform exercises. [Results] With regards to forced vital capacity, forced expiratory volume at one second, and peak cough flow rate before and after the exercises, the control group did not show any significant differences while the experimental group showed statistically significant increases in all three parameters. [Conclusion] The results indicate that cervical range of motion exercises can effectively improve the pulmonary function and coughing ability of stroke patients intubated with tracheostomy tubes, and that cervical range of motion exercises can help in the removal of tracheostomy tubes.

Lateral Cervical Spine Radiography to Demonstrate Absence of Bony Displacement After Intubation in a Patient with an Acute Type III Odontoid Fracture

A 72-year-old patient with an acute traumatic Type III odontoid fracture presented to the operating room for an urgent orthopedic procedure with a history of uncontrolled gastroesophageal reflux, a full stomach, and active vomiting. Rather than fiberoptic intubation, a rapid sequence intubation with manual inline stabilization was performed using a videolaryngoscope. A lateral cervical spine radiograph immediately after intubation showed no change in alignment of the fracture of C1-C2. In the presence of cervical spine instability, a postintubation radiograph provides assurance that the cervical spine is appropriately aligned during subsequent surgery.

Alternative intubation techniques vs Macintosh laryngoscopy in patients with cervical spine immobilization: systematic review and meta-analysis of randomized controlled trials

Background. Immobilization of the cervical spine worsens tracheal intubation conditions. Various intubation devices have been tested in this setting. Their relative usefulness remains unclear.

Methods. We searched MEDLINE, EMBASE, and the Cochrane Library for randomized controlled trials comparing any intubation device with the Macintosh laryngoscope in human subjects with cervical spine immobilization. The primary outcome was the risk of tracheal intubation failure at the first attempt. Secondary outcomes were quality of glottis visualization, time until successful intubation, and risk of oropharyngeal complications.

Results. Twenty-four trials (1866 patients) met inclusion criteria. With alternative intubation devices, the risk of intubation failure was lower compared with Macintosh laryngoscopy [risk ratio (RR) 0.53; 95% confidence interval (CI) 0.35–0.80]. Meta-analyses could be performed for five intubation devices (Airtraq, Airwayscope, C-Mac, Glidescope, and McGrath). The Airtraq was associated with a statistically significant reduction of the risk of intubation failure at the first attempt (RR 0.14; 95% CI 0.06–0.33), a higher rate of Cormack–Lehane grade 1 (RR 2.98; 95% CI 1.94–4.56), a reduction of time until successful intubation (weighted mean difference −10.1 s; 95% CI −3.2 to −17.0), and a reduction of oropharyngeal complications (RR 0.24; 95% CI 0.06–0.93). Other devices were associated with improved glottis visualization but no statistically significant differences in intubation failure or time to intubation compared with conventional laryngoscopy.

Conclusions. In situations where the spine is immobilized, the Airtraq device reduces the risk of intubation failure. There is a lack of evidence for the usefulness of other intubation devices.

Clinical evaluation and airway management for adults with cervical spine instability

Airway management of patients with cervical spine instability may be difficult as a result of immobilization, and may be associated with secondary neurologic injury related to cervical spine motion. Spinal cord instability is most common in patients with trauma, but there are additional congenital and acquired conditions that predispose to subacute cervical spine instability. Patients with suspected instability should receive immobilization during airway management with manual in-line stabilization. The best strategy for airway management is one that applies the technique with the highest likelihood of success on the first attempt and the lowest biomechanical influence on a potentially unstable spine.

Airway management of patients with traumatic brain injury/C-spine injury

Traumatic brain injury (TBI) is usually combined with cervical spine (C-spine) injury. The possibility of C-spine injury is always considered when performing endotracheal intubation in these patients. Rapid sequence intubation is recommended with adequate sedative or analgesics and a muscle relaxant to prevent an increase in intracranial pressure during intubation in TBI patients. Normocapnia and mild hyperoxemia should be maintained to prevent secondary brain injury. The manual-in-line-stabilization (MILS) technique effectively lessens C-spine movement during intubation. However, the MILS technique can reduce mouth opening and lead to a poor laryngoscopic view. The newly introduced video laryngoscope can manage these problems. The AirWay Scope® (AWS) and AirTraq laryngoscope decreased the extension movement of C-spines at the occiput-C1 and C2-C4 levels, improving intubation conditions and shortening the time to complete tracheal intubation compared with a direct laryngoscope. The Glidescope® also decreased cervical movement in the C2-C5 levels during intubation and improved vocal cord visualization, but a longer duration was required to complete intubation compared with other devices. A lightwand also reduced cervical motion across all segments. A fiberoptic bronchoscope-guided nasal intubation is the best method to reduce cervical movement, but a skilled operator is required. In conclusion, a video laryngoscope assists airway management in TBI patients with C-spine injury.

Influence of GlideScope assisted endotracheal intubation on intraocular pressure in ophthalmic patients

Background:

Traditional Macintoch laryngoscopy is known to cause a rise in intraocular pressure (IOP), tachycardia and hypertension. These changes are not desirable in patients with glaucoma and open globe injury. GlideScope is a video laryngoscope that functions independent of the line of sight, reduces upward lifting forces for glottic exposure and requires less cervical neck movement for intubation, making it less stimulating than Macintosh laryngoscopy.

Aim:

The aim was to assess the variations in IOP and hemodynamic changes after GlideScope assisted intubation.

Materials and Methods:

After approval of the local Institutional Research and Ethical Board and informed patient consent, 50 adult American Society of Anesthesiologist I and II patients with normal IOP were enrolled in a prospective, randomized study for ophthalmic surgery requiring tracheal intubation. In all patients, trachea was intubated using either GlideScope or Macintoch laryngoscope. IOP of nonoperated eye, heart rate and blood pressure were measured as baseline, 1 min after induction, 1 min and 5 min after tracheal intubation.

Results:

IOP was not significantly different between groups before and after anesthetic induction and 5 min after tracheal intubation (P = 0.217, 0.726, and 0.110 respectively). The only significant difference in IOP was at 1 min after intubation (P = 0.041). No significant difference noted between groups in mean arterial pressure (P = 0.899, 0.62, 0.47, 0.82 respectively) and heart rate (P = 0.21, 0.72, 0.07, 0.29, respectively) at all measurements.

Conclusion:

GlideScope assisted tracheal intubation shown lesser rise in IOP at 1 min after intubation in comparison to Macintoch laryngoscope, suggesting that GlideScope may be preferable to Macintosh laryngoscope.

A Comparison of the Effects of Different Types of Laryngoscope on the Cervical Motions: Randomized Clinical Trial

BACKGROUND

The rate of cervical injury among all trauma patients is 3.1%. The most important point during intubation of those patients is not to increase the cervical injury.

AIMS

In this study, we hypothesize that there will be a minimal cervical extension during a laryngoscopy with the use of optical view laryngoscopes.

STUDY DESIGN

Prospective, randomized clinical trial.

METHODS

One hundred and fifty adult patients with ASA physical status I to III were enrolled in our study. After routine anesthesia induction, we randomly assigned the patients into three groups according to the type of laryngoscope. Macintosh type, Truview EVO2(®) type and Airtraq® type laryngoscopes were used in Group DL (n=50), Group TW (n=50) and Group ATQ (n=50), respectively. After applying general anesthesia induction and mask ventilation, all of the patients were positioned in the neutral position. An inclinometer was placed on the forehead of the patients. Then, the extension angle during intubation and the Cormack-Lehane Score were measured and the time to intubation was recorded.

RESULTS

One of the 50 patients in the DL Group, 2 of the 50 patients in the TW Group, and 4 of the 50 patients in the ATQ Group were excluded from the study because of the failure of intubation at defined times. The angle of cervical extension during laryngoscopy was found to be 27.24±6.71, 18.08±7.53, and 14.54±4.09 degrees in the Groups DL, TV and ATQ, respectively; these differences also had statistical significance (p=0.000). The duration of intubation was found to be 13.59±5.49, 23.60±15.23, and 29.80±13.82 seconds in Groups DL, TV and ATQ, respectively (p=0.000).

CONCLUSION

A minimal cervical motion was obtained during tracheal intubation with the use of Truview EVO2® and Airtraq® types of laryngoscope compared with the Macintosh laryngoscope. (ClinicalTrials.gov Identifier: NCT02191904).

Laryngoscope and a new tracheal tube assist lightwand intubation in difficult airways due to unstable cervical spine

PURPOSE

The WEI Jet Endotracheal Tube (WEI JET) is a new tracheal tube that facilitates both oxygenation and ventilation during the process of intubation and assists tracheal intubation in patients with difficult airway. We evaluated the effectiveness and usefulness of the WEI JET in combination with lightwand under direct laryngoscopy in difficult tracheal intubation due to unstable cervical spine.

METHODS

Ninety patients with unstable cervical spine disorders (ASA I-III) with general anaesthesia were included and randomly assigned to three groups, based on the device used for intubation: lightwand only, lightwand under direct laryngoscopy, lightwand with WEI JET under direct laryngoscopy.

RESULTS

No statistically significant differences were detected among three groups with respect to demographic characteristics and C/L grade. There were statistically significant differences between three groups for overall intubation success rate (p = 0.015) and first attempt success rate (p = 0.000). The intubation time was significantly longer in the WEI group (110.8±18.3 s) than in the LW group (63.3±27.5 s, p = 0.000) and DL group (66.7±29.4 s, p = 0.000), but the lowest SpO2 in WEI group was significantly higher than other two groups (p<0.01). The WEI JET significantly reduced successful tracheal intubation attempts compared to the LW group (p = 0.043). The severity of sore throat was similar in three groups (p = 0.185).

CONCLUSIONS

The combined use of WEI JET under direct laryngoscopy helps to assist tracheal intubation and improves oxygenation during intubation in patients with difficult airway secondary to unstable spine disorders.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-TRC-14005141.

Emergency department evaluation and treatment of cervical spine injuries

Most spinal cord injuries involve the cervical spine, highlighting the importance of recognition and proper management by emergency physicians. Initial cervical spine injury management should follow the ABCDE (airway, breathing, circulation, disability, exposure) procedure detailed by Advanced Trauma Life Support. NEXUS (National Emergency X-Radiography Utilization Study) criteria and Canadian C-spine Rule are clinical decision-making tools providing guidelines of when to obtain imaging. Computed tomography scans are the preferred initial imaging modality. Consider administering intravenous methylprednisolone after discussion with the neurosurgical consultant in patients who present with spinal cord injuries within 8 hours.

Comparison between Glidescope and Lightwand for tracheal intubation in patients with a simulated difficult airway

Background

Although Lightwand and Glidescope have both shown high success rates for intubation, there has been no confirmation as to which device is most effective for difficult endotracheal intubation. We compared the Glidescope and Lightwand devices in terms of duration of intubation and success rate at the first attempt in a simulated difficult airway situation.

Methods

Fifty-eight patients were randomized to undergo tracheal intubation with either the Glidescope (Glidescope group, n = 29) or the Lightwand (Lightwand group, n = 29). All patients were fitted with a semi-hard cervical collar in order to simulate a difficult airway, and intubation was attempted with the assigned airway device. The data collected included the rate of successful endotracheal intubation, the number of attempts required, the duration of the intubation, as well as the interincisor distance, hemodynamic variables, and adverse effects.

Results

There was no difference between Glidescope group (92.6%) and Lightwand group (96.4%) in terms of success rate for the first attempt at intubation. The duration of successful intubation for the first tracheal intubation attempt was significantly longer in Glidescope group than in Lightwand group (46.9 sec vs 29.5 sec, P = 0.001). All intubations were completed successfully within two intubation attempts. The incidence of hypertension was significantly higher in Glidescope group than in Lightwand group (51.9% vs 17.9%, P = 0.008).

Conclusions

In a simulated difficult airway situation, endotracheal intubation using Lightwand yielded a shorter duration of intubation and lower incidence of hypertension than when using Glidescope.

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.

Efficacy of video-guided laryngoscope in airway management skills of medical students

Background & Aims:

Video-guided laryngoscopy, though unproven in achieving better success rates of laryngoscopy outcome and intubation, seems to provide better glottic visualization compared with direct laryngoscopy. The objective of this study was to compare the efficacy of video-guided laryngoscope (VGL) in the airway management skills of medical students.

Materials and Methods:

Medical students throughout their anesthesiology rotations were enrolled in this study. All students received standard training in the airway management during their course and were randomly allocated into two 20 person groups. In Group D, airway management was performed by direct laryngoscopy via Macintosh blade and in Group G intubation was performed via VGL. Time to intubation, number of laryngoscopy attempts and success rate were noted. Successful intubation was considered as the primary outcome.

Statistical Analysis:

All data were analyzed using SPSS 16 software. Chi-square and Fisher's exact test were used for analysis of categorical variables. For analyzing continuous variables independent t-test was used. P < 0.05 was considered as statistically significant.

Results:

Number of laryngoscopy attempts was less in Group G in comparison to Group D; this, however, was statistically insignificant (P: 0.18). Time to intubation was significantly less in Group G as compared to Group D (P: 0.02). Successful intubation in Group G was less frequently when compared to Group D (P: 0.66). Need for attending intervention, esophageal intubation and hypoxemic events during laryngoscopy were less in Group G; this, however, was statistically insignificant.

Conclusions:

The use of video-guided laryngoscopy improved the first attempt success rate, time to intubation, laryngoscopy attempts and airway management ability of medical students compared to direct laryngoscopy.

Videolaryngoscopy

The approach to airway management has undergone a dramatic transformation since the advent of videolaryngoscopy (VL). Videolaryngoscopes have quickly gained popularity as an intubation device in a variety of clinical scenarios and settings, as well as in the hands of airway experts and non-experts. Their indirect view of upper airway improves glottic visualization, including in suspected or encountered difficult intubation. Yet, more studies are needed to determine whether VL actually improves endotracheal intubation (ETI) success rates, intubation times, and first attempt success rates; and thereby a potential replacement to traditional direct laryngoscopy. Furthermore, advances in technology have heralded a wide array of models each with their own strengths, weaknesses, and optimal applications. Such limitations need to be better understood and alternative strategies should be available. Thus, the role of VL continues to evolve. Though it is clear VL expands the armamentarium not only for anesthesiologists, but all healthcare providers potentially involved in airway management.

Comparing GlideScope Video Laryngoscope and Macintosh Laryngoscope Regarding Hemodynamic Responses During Orotracheal Intubation: A Randomized Controlled Trial

BACKGROUND

To determine if the GlideScope® videolaryngoscope (GVL) could attenuate the hemodynamic responses to orotracheal intubation compared with conventional Macintosh laryngoscope.

OBJECTIVES

The aim of this relatively large randomized trial was to compare the hemodynamic stress responses during laryngoscopy and tracheal intubation using GVL versus MCL amongst healthy adult individuals receiving general anesthesia for elective surgeries.

PATIENTS AND METHODS

Ninety five healthy adult patients with American Society of Anesthesiologists physical status class I or II that were scheduled for elective surgery under general anesthesia were randomly allocated to either Macintosh or GlideScope arms. All patients received a standardized protocol of general anesthesia. Hemodynamic changes associated with intubation were recorded before and at 1, 3 and 5 minutes after the intubation. The time taken to perform endotracheal intubation was also noted in both groups.

RESULTS

Immediately before laryngoscopy (pre-laryngoscopy), the values of all hemodynamic variables did not differ significantly between the two groups (All P values > 0.05). Blood pressures and HR values changed significantly over time within the groups. Time to intubation was significantly longer in the GlideScope (15.9 ± 6.7 seconds) than in the Macintosh group (7.8 ± 3.7 sec) (P< 0.001). However, there were no significant differences between the two groups in hemodynamic responses at all time points.

CONCLUSIONS

The longer intubation time using GVL suggests that the benefit of GVL could become apparent if the time taken for orotracheal intubation could be decreased in GlideScope group.

Alternative airways for the pediatric emergency department

Securing the pediatric airway in the emergency setting is an uncommon event that is complicated by anatomic, physiologic, and environmental factors. Even more uncommonly, practitioners are faced with the added complication of a difficult airway, and the question of what alternatives to traditional endotracheal intubation are available and most useful may arise. Timely and effective intervention determines the patient's clinical outcome. The purpose of this review was to detail specific alternative airway management strategies and tools for use in the pediatric emergency department.

[Cervical spine instability in the surgical patient]

Many congenital and acquired diseases, including trauma, may result in cervical spine instability. Given that airway management is closely related to the movement of the cervical spine, it is important that the anesthesiologist has detailed knowledge of the anatomy, the mechanisms of cervical spine instability, and of the effects that the different airway maneuvers have on the cervical spine. We first review the normal anatomy and biomechanics of the cervical spine in the context of airway management and the concept of cervical spine instability. In the second part, we review the protocols for the management of cervical spine instability in trauma victims and some of the airway management options for these patients.

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.

Assessment of cervical spine movement during laryngoscopy with Macintosh and Truview laryngoscopes

Background:

Truview laryngoscope provides an indirect view of the glottis and will cause less cervical spine movement since a ventral lifting force will not be required to visualize the glottis compared to Macintosh laryngoscope.

Materials and Methods:

A randomized crossover study to assess the degree of movement of cervical spine during endotracheal intubation with Truview laryngoscope was conducted in 25 adult ASA-I patients. After a standard anesthetic technique laryngoscopy was performed twice in each patient using in turn both the Macintosh and Truview laryngoscopes. A baseline radiograph with the head and neck in a neutral position was followed by a second radiograph taken during each laryngoscopy. An experienced radiologist analyzed and measured the cervical movement.

Results:

Significant cervical spine movement occurred at all segments when compared to the baseline with both the Macintosh and Truview laryngoscopes (P < 0.001). However, the movement was significantly less with Truview compared to the Macintosh laryngoscope at C₀–C₁ (21%; P = 0.005) and C₁–C₂ levels (32%; P = 0.009). The atlantooccipital distance (AOD) traversed while using Truview laryngoscope was significantly less than with Macintosh blade (26%; P = 0.001). Truview blade produced a better laryngoscopic view (P = 0.005) than Macintosh blade, but had a longer time to laryngoscopy (P = 0.04).

Conclusion:

Truview laryngoscope produced a better laryngoscopic view of glottis as compared with Macintosh laryngoscopy. It also produced significantly less cervical spine movement at C₀–C₁ and C₁–C₂ levels than with Macintosh laryngoscope in patients without cervical spine injury and without manual in-line stabilization (MILS). Further studies are warranted with Truview laryngoscope using MILS.

Comparing the novel GlideScope Groove videolaryngoscope with conventional videolaryngoscopy: a randomized mannequin study of novice providers

STUDY OBJECTIVE

To compare the GlideScope Groove (GG) with conventional GlideScope videolaryngoscopy (GVL) and direct laryngoscopy (DL) on intubation times, intubation attempts, and glottic visualization of an airway mannequin by medical students.

DESIGN

Randomized crossover trial.

SETTING

Intensive care unit of an academic tertiary-care hospital.

PARTICIPANTS

34 medical students with no airway management experience.

MEASUREMENTS

Each participant received standardized video instruction on all three laryngoscopes and was given 10 minutes to practice with each device. The participants had two attempts using DL, and then had two attempts each with either the GG or GVL in random order.

MEASUREMENTS

Time-to-intubate the mannequin in seconds was recorded. Secondary outcomes were Cormack-Lehane grade and number of intubation attempts, also recorded.

MAIN RESULTS

The median number of seconds required to successfully intubate the mannequin with DL, GVL, and GG were 17.4 seconds [interquartile range (IQR) 13.2 - 22.1)], 17.7 seconds (IQR 14.9 - 21.0), and 21.7 seconds (IQR 15.4 - 37.0), respectively. No differences in time-to-intubate was noted among the three devices (P = 0.45). A Cormack-Lehane grade 1 view was obtained for 25 of 34 participants (74%) with DL, 32 of 34 participants (94%) with GVL, and 34 of 34 participants (100%) with GG. First-attempt intubation success was 30 of 34 participants (88%) with DL, 34 of 34 participants (100%) with GVL, and 11 of 34 participants (32%) with GG. Using the GG, 6 of 24 participants (18%) required three attempts. More attempts were required for the GG than for DL (P < 0.001) or GVL (P < 0.001).

CONCLUSIONS

GG was not superior to DL or GVL in time-to-intubate an airway mannequin.

Anesthetic considerations in acute spinal cord trauma

Patients with actual or potential spinal cord injury (SCI) are frequently seen at adult trauma centers, and a large number of these patients require operative intervention. All polytrauma patients should be assumed to have an SCI until proven otherwise. Pre-hospital providers should take adequate measures to immobilize the spine for all trauma patients at the site of the accident. Stabilization of the spine facilitates the treatment of other major injuries both in and outside the hospital. The presiding goal of perioperative management is to prevent iatrogenic deterioration of existing injury and limit the development of secondary injury whilst providing overall organ support, which may be adversely affected by the injury. This review article explores the anesthetic implications of the patient with acute SCI. A comprehensive literature search of Medline, Embase, Cochrane database of systematic reviews, conference proceedings and internet sites for relevant literature was performed. Reference lists of relevant published articles were also examined. Searches were carried out in October 2010 and there were no restrictions by study design or country of origin. Publication date of included studies was limited to 1990–2010.

Trauma care today, what's new?

Injury is the fourth leading cause of death in the US, and the leading cause of death in younger age. Trauma is primarily a disease of the young and accounts for more years of productive life lost than any other illness. Consequently, almost every health care provider encounters trauma patients from time to time. Many of these patients are critically ill and pose several challenges in the acute phase, including airway and ventilation, fluid management, intracranial pressure control, etc. In the last decade, several strategies and treatment options have been studied in trauma care along with improvement in technologies. In this review, we will discuss a few of the new developments and updates in trauma care.

[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.

Use of video-assisted intubation devices in the management of patients with trauma

Patients with trauma may have airways that are difficult to manage. Patients with blunt trauma are at increased risk of unrecognized cervical spine injury, especially patients with head trauma. Manual in-line stabilization reduces cervical motion and should be applied whenever a cervical collar is removed. All airway interventions cause some degree of cervical spine motion. Flexible fiberoptic intubation causes the least cervical motion of all intubation approaches, and rigid video laryngoscopy provides a good laryngeal view and eases intubation difficulty. In emergency medicine departments, video laryngoscopy use is growing and observational data suggest an improved success rate compared with direct laryngoscopy.

A comparison of 4 airway devices on cervical spine alignment in cadaver models of global ligamentous instability at c1-2

BACKGROUND

The effects of advanced airway management on cervical spine alignment in patients with upper cervical spine instability are uncertain.

METHODS

To examine the potential for mechanical disruption during endotracheal intubation in cadavers with unstable cervical spines, we performed a prospective observational cohort study with 3 cadaver subjects. We created an unstable, type II odontoid fracture with global ligamentous instability at C1-2 in lightly embalmed cadavers, followed by repetitive intubations with 4 different airway devices (Airtraq laryngoscope, Lightwand, intubating laryngeal mask airway [LMA], and Macintosh laryngoscope) while manual in-line stabilization was applied. Motion analysis data were collected using an electromagnetic device to assess the degree of angular movement in 3 axes (flexion-extension, axial rotation, and lateral bending) during the intubation trials with each device. Intubation was performed by either an emergency medical technician or attending anesthesiologist.

RESULTS

Overall, 153 intubations were recorded with the 4 devices. The Lightwand technique resulted in significantly less flexion-extension and axial rotation at C1-2 than with the intubating LMA (mean difference in flexion-extension 3.2° [95% confidence interval {CI}, 0.9°-5.5°], P = 0.003; mean difference in axial rotation 1.6° [95% CI, 0.3°-2.8°], P = 0.01) and Macintosh laryngoscope (mean difference in flexion-extension 3.1° [95% CI, 0.8°-5.4°], P = 0.005; mean difference in axial rotation 1.4° [95% CI 0.1°-2.6°], P = 0.03).

CONCLUSIONS

In cadavers with instability at C1-2, the Lightwand technique produced less motion than the Macintosh and intubating LMA.

Videolaryngoscopy with glidescope reduces cervical spine movement in patients with unsecured cervical spine

BACKGROUND

Unconscious patients with severe trauma often require urgent endotracheal intubation. In trauma victims with possible cervical spine injury, any movement of the head and neck should be avoided.

STUDY OBJECTIVES

We investigated the effect of GlideScope videolaryngoscopy on cervical spine movement compared with conventional laryngoscopy in anesthetized patients with unsecured cervical spines.

METHODS

Sixty patients scheduled for elective surgery with general anesthesia and without anticipated airway problems were enrolled in the study after ethics committee approval and written informed consent. Intubation was performed with videolaryngoscopy (GlideScope(®), Verathon Inc., Bothell, WA) or conventional laryngoscopy (MacIntosh). Using video motion analysis with a lateral view, the maximum extension angle α was measured with reference to anatomical points (baseline and line drawn from processus mastoideus to os frontale [glabella]). Values were analyzed using Mann Whitney U-tests.

RESULTS

The deviation of α was a median 11.8° in the videolaryngoscope group and 14.3° in the conventional group (p = 0.045), with a maximum of 19.2° (videolaryngoscopy) vs. 29.3° (conventional). Intubation by physicians with some experience in videolaryngoscopy was associated with a reduced angle deviation (α = 10.3°) compared to inexperienced physicians (12.8°, p = 0.019). Intubation time was a median 24 s (min/max 12/75 s) in the MacIntosh group and 53 s (min/max 28/210 s) in the GlideScope group. In 3 patients randomized to the conventional group in whom conventional intubation failed, intubation could be successfully performed using videolaryngoscopy.

CONCLUSION

GlideScope videolaryngoscopy reduces movements of the cervical spine in patients with unsecured cervical spines and therefore might reduce the risk of secondary damage during emergency intubation of patients with cervical spine trauma.

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.

[Orotracheal intubation difficulty with lighted stylet: correlation of body mass index and neck circumference]

OBJECTIVES

To evaluate the difficulty of intubation with a lighted stylet by correlating the body mass index (BMI) with the neck or cervical circumference (CC), and to establish the values of BMI and CC that could help identify a possible difficult intubation with this device.

PATIENTS AND METHODS

An observational and correlational study was performed on selected patients by consecutive sampling who were intubated using the lighted stylet. Variables such as age, gender, ASA physical status, BMI, CC, transillumination intensity, Cormack-Lehane grade, and Mallampati scores, were recorded. Multivariable analyses were performed.

RESULTS

103 patients were included. The mean age of the patients was 39.0 ± 16.6 years, BMI 28.6 ± 6.8 kg/m² (33% obese and 29,1% overweight), CC 37.8 ± 4.6 cm. Those patients who presented difficulty for intubation had a CC 39.9 ± 5.2 cm (P ≤ 0.05), and a BMI 33.8 ± 7.6 kg/m² (P = 0.01).

CONCLUSION

A lineal correlation exists between a BMI above 33 kg/m² and/or a CC greater than 40 cm and a difficult intubation using lighted stylet. Another method other than transillumination is recommended for orotracheal intubation in a patient with both characteristics.

Video Laryngoscopy in the Prehospital Setting

In the prehospital setting, the emergency care provider must anticipate that some patients will manifest with difficult airways. The use of video laryngoscopy to secure an airway in the prehospital setting has not been explored widely, but has the potential to be a useful tool. This article briefly reviews some of the major video laryngoscopes on the market and their usefulness in the prehospital setting. Studies and case reports indicate that the video laryngoscope is a promising device for emergency intubation, and it has been predicted that, in the future, video laryngoscopy will dominate the field of emergency airway management.

Direct laryngoscopy always should be retained as a primary skill; however, the video laryngoscope has the potential to be a good primary choice for the patient with potential cervical spine injuries or limited jaw or spine mobility, and in the difficult-to-access patient.The role of video laryngoscopes in securing an airway in head and neck trauma victims in the prehospital setting has yet to be determined, but offers interesting possibilities. Further clinical studies are necessary to evaluate its role in airway management by prehospital emergency medical services.

Airway management in neuroanesthesiology

Airway management for neuroanesthesiology brings together some key principles that are shared throughout neuroanesthesiology. This article appropriately targets the cervical spine with associated injury and the challenges surrounding airway management. The primary focus of this article is on the unique airway management obstacles encountered with cervical spine injury or cervical spine surgery, and unique considerations regarding functional neurosurgery are addressed. Furthermore, topics related to difficult airway management for those with rheumatoid arthritis or pituitary surgery are reviewed.

An adult patient with Klippel-Feil syndrome presenting for repeat operation: a cautionary tale of the GlideScope

The introduction of video laryngoscopes has increased the success of intubating the difficult airway. However, failures have been reported in the literature that are associated with certain patient characteristics. Klippel-Feil Syndrome is a condition that typically presents with decreased cervical spine motion, a characteristic that has been associated with GlideScope failure. After an uneventful first anesthetic, a case of a near impossible-to-intubate occurred in a patient with Klippel-Feil Syndrome.

Comparison of 4 airway devices on cervical spine alignment in a cadaver model with global ligamentous instability at C5-C6

STUDY DESIGN

Human cadaveric study using various intubation devices in a cervical spine instability model.

OBJECTIVE

We sought to evaluate various intubation techniques and determine which device results in the least cervical motion in the setting of a global ligamentous instability model.

SUMMARY OF BACKGROUND DATA

Many patients presenting with a cervical spine injury have other injuries that may require rapid airway management with endotracheal intubation. Secondary neurologic injuries may occur in these patients because of further displacement at the level of injury, vascular insult, or systemic decrease in oxygen delivery. The most appropriate technique for achieving endotracheal intubation in the patient with a cervical spine injury remains controversial.

METHODS

A global ligamentous instability at the C5-C6 vertebral level was created in lightly embalmed cadavers. An electromagnetic motion analysis device (Liberty; Polhemus, Colchester, VT) was used to assess the amount of angular and linear translation in 3 planes during intubation trials with each of 4 devices (Airtraq laryngoscope, lighted stylet, intubating LMA, and Macintosh laryngoscope). The angular motions measured were flexion-extension, axial rotation, and lateral bending. Linear translation was measured in the medial-lateral (ML), axial, and anteroposterior planes. Intubation was performed by either an emergency medical technician or by a board-certified attending anesthesiologist. Both time to intubate as well as failure to intubate (after 3 attempts) were recorded.

RESULTS

There was no significant difference shown with regards to time to successfully intubate using the various devices. It was shown that the highest failure-to-intubate rate occurred with use of the intubating LMA (ILMA) (23%) versus 0% for the others. In flexion/extension, we were able to demonstrate that the Lightwand (P = 0.005) and Airtraq (P = 0.019) resulted in significantly less angular motion than the Macintosh blade. In anterior/posterior translation, the Lightwand (P = 0.005), Airtraq (P = 0.024), and ILMA (P = 0.021) all caused significantly less linear motion than the Macintosh blade. In axial rotation, the Lightwand (P = 0.017) and Airtraq (P = 0.022) resulted in significantly less angular motion than the Macintosh blade. In axial translation (P = 0.037) and lateral bending (P = 0.003), the Lightwand caused significantly less motion than the Macintosh blade.

CONCLUSION

In a cadaver model of C5-C6 instability, the greatest amount of motion was caused by the most commonly used intubation device, the Macintosh blade. Intubation with the Lightwand resulted in significantly less motion in all tested parameters (other than ML translation) as compared with the Macintosh blade. It should also be noted that the Airtraq caused less motion than the Macintoshblade in 3 of the 6 tested planes. There were no significant differences in failure rate or the amount of time it took to successfully intubate in comparing these techniques. We therefore recommend the use of the Lightwand, followed by the Airtraq, in the setting of a presumed unstable cervical spine injury over the Macintosh laryngoscope.

Evidence for benefit vs novelty in new intubation equipment

A myriad of new intubation equipment has been introduced commercially since the appearance of Macintosh/Miller blades in the 1940s. We review the role of devices that are relevant to current clinical practice based on their presence in the scientific literature. The comparative performance of new vs traditional direct laryngoscopes, their complications, their use in awake intubation techniques and the prediction of unsuccessful intubation with new devices are reviewed. Manikin studies are of limited value in this area. We conclude that in both predicted and unpredicted difficult or failed intubation, carefully selected new intubation equipment has a high success rate for tracheal intubation. Ideally, such devices should be available in all settings where tracheal intubation is performed. Most importantly, experience and competence with any of the new devices are critical for their successful use in any clinical setting.

Glidescope® video-laryngoscopy versus direct laryngoscopy for endotracheal intubation: a systematic review and meta-analysis

Introduction

The Glidescope^® video-laryngoscopy appears to provide better glottic visualization than direct laryngoscopy. However, it remains unclear if it translates into increased success with intubation.

Methods

We systematically searched electronic databases, conference abstracts, and article references. We included trials in humans comparing Glidescope^® video-laryngoscopy to direct laryngoscopy regarding the glottic view, successful first-attempt intubation, and time to intubation. We generated pooled risk ratios or weighted mean differences across studies. Meta-regression was used to explore heterogeneity based on operator expertise and intubation difficulty.

Results

We included 17 trials with a total of 1,998 patients. The pooled relative risk (RR) of grade 1 laryngoscopy (vs ≥ grade 2) for the Glidescope^® was 2.0 [95% confidence interval (CI) 1.5 to 2.5]. Significant heterogeneity was partially explained by intubation difficulty using meta-regression analysis (P = 0.003). The pooled RR for nondifficult intubations of grade 1 laryngoscopy (vs ≥ grade 2) was 1.5 (95% CI 1.2 to 1.9), and for difficult intubations it was 3.5 (95% CI 2.3 to 5.5). There was no difference between the Glidescope^® and the direct laryngoscope regarding successful first-attempt intubation or time to intubation, although there was significant heterogeneity in both of these outcomes. In the two studies examining nonexperts, successful first-attempt intubation (RR 1.8, 95% CI 1.4 to 2.4) and time to intubation (weighted mean difference −43 sec, 95% CI −72 to −14 sec) were improved using the Glidescope^®. These benefits were not seen with experts.

Conclusion

Compared to direct laryngoscopy, Glidescope^® video-laryngoscopy is associated with improved glottic visualization, particularly in patients with potential or simulated difficult airways.

Modified lightwand intubation in a child with spondyloepiphyseal dysplasia congenita

This is the case report on a 1-year 9-month-old boy suffering from spondyloepiphyseal dysplasia congenita who was successfully intubated with our modified lightwand intubation procedure for general anesthesia to undergo bilateral herniorrhaphy despite the great likelihood of facing a difficult airway because of unstable cervical spine. We bent the pediatric wand after it was encased in an endotracheal (ET) tube of appropriate diameter. The light tip of the wand was let to protrude just out of the bevel of the ET tube. Once the light bulb properly transilluminated the trachea, the ET tube was threaded gently into the trachea. The patient recovered from anesthesia smoothly and was discharged on the next day. This maneuver can facilitate both visual and tactile confirmations of the position and proper tube size. The effectiveness and safety of our modified lightwand intubation procedure is well demonstrated.

Comparing the performance of traditional direct laryngoscope with three indirect laryngoscopes: A prospective manikin study in normal and difficult airway scenarios

OBJECTIVES

The aim of the present study was to evaluate the performance of three indirect laryngoscopes, Truview EVO2 laryngoscope, Clarus Levitan fiberoptic stylet and AirwayScope AWS, in comparison with direct Macintosh laryngoscope (ML) when performed in normal and difficult airway scenarios.

METHODS

This prospective comparative study recruited 30 emergency physicians familiar with direct laryngoscopic intubation. Intubations were performed on manikin and were repeated twice for both scenarios. The primary end points were intubation time and rate of failed intubation. Glottis visualization was graded on Cormack and Lehane score and VAS.

RESULTS

In normal airway scenario: AWS had shortest intubation time (6.0 s) followed by ML (8.7 s); VAS score of ML and AWS was lower (easier to use) than the other two devices; Cormack and Lehane score was similar for all devices. In difficult airway scenario: AWS had shortest intubation time (5.9 s); VAS score of AWS was lower than the other three devices; TVL, FOS, AWS had better Cormack and Lehane score than ML. Intubation time, rate of failed intubation, and Cormack and Lehane score were similar between attempts in both scenarios. Learning effect was significant in FOS in both scenarios and in TVL in normal airway scenario.

CONCLUSIONS

AWS performed best in normal and difficult airways. ML performed better than TVL and FOS in normal airways. Performances of ML, TVL and FOS were similar in difficult airways. Skills with AWS could be mastered rapidly. TVL and FOS required more practice to gain expertise.

Equipment to manage a difficult airway during anaesthesia

Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).