Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients.

This landmark paper by Cooper Et. Al. was recognized as an important contribution to Airway understanding in Canada and the world. This was the first general use paper evaluating the GlideScope Video Laryngoscope.

Can J Anaesth. 2005 Feb;52(2):191-8.

Cooper RM1, Pacey JA, Bishop MJ, McCluskey SA.

Abstract

PURPOSE: 

To evaluate a new videolaryngoscope and assess its ability to provide laryngeal exposure and facilitate intubation.

METHODS: 

Five centres, involving 133 operators and a total of 728 consecutive patients, participated in the evaluation of a new video-laryngoscope [GlideScope (GS)]. Many operators had limited or no previous GS experience. We collected information about patient demographics and airway characteristics, Cormack-Lehane (C/L) views and the ease of intubation using the GS. Failure was defined as abandonment of the technique.

RESULTS: 

Data from six patients were incomplete and were excluded. Excellent (C/L 1) or good (C/L 2) laryngeal exposure was obtained in 92% and 7% of patients respectively. In all 133 patients in whom both GS and direct laryngoscopy (DL) were performed, GS resulted in a comparable or superior view. Among the 35 patients with C/L grade 3 or 4 views by DL, the view improved to a C/L 1 view in 24 and a C/L 2 view in three patients. Intubation with the GS was successful in 96.3% of patients. The majority of the failures occurred despite a good or excellent glottic view.

CONCLUSIONS: 

GS laryngoscopy consistently yielded a comparable or superior glottic view compared with DL despite the limited or lack of prior experience with the device. Successful intubation was generally achieved even when DL was predicted to be moderately or considerably difficult. GS was abandoned in 3.7% of patients. This may reflect the lack of a formal protocol defining failure, limited prior experience or difficulty manipulating the endotracheal tube while viewing a monitor.

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Learning Curve of the Infant GlideScope® Cobalt Video Laryngoscope in Anesthesiology Residents

Karsli C, et al., J Anesth Clin Care 2015, 2:1

Mazen Faden1, Hossam El-Beheiry2, Carolyne Pehora3 and
Cengiz Karsli3*
1Department of Anesthesia & Critical Care, King Abdulaziz University,
Jeddah, Kingdom of Saudi Arabia
2Department of Anesthesia, Trillium Health Centre, Toronto, Canada
3Department of Anesthesia and Pain Medicine, The Hospital for Sick
Children, University of Toronto, Toronto, Canada

 Cengiz Karsli, Department of Anesthesia and Pain

Medicine, The Hospital for Sick Children, University of Toronto, Toronto M5G

1X8, Canada, Tel: +1 4168137341; E-mail: cengiz.karsli@sickkids.ca

 Abstract

Background

The ease of use and success rate associated with GlideScope®intubation of infant tracheas by anesthesiology residents in their first
pediatric rotation is unknown.
Objective
The purpose of this study was to evaluate the learning curve
associated with infant GlideScope® Cobalt Video Laryngoscope
intubation by anesthesiology residents compared to direct
laryngoscopy.
Methods
Sixteen anesthesiology residents who had no prior experience
with infant airway management performed a total of 10 tracheal
intubations each (5 GlideScope® and 5 direct laryngoscope,
randomized) in infants weighing 10 kg or less. Primary end points
included time to optimum view of the vocal cords and time to
tracheal intubation. Multivariate ANOVA and pair-wise comparisons
were used to analyze the data.
Results
There were no significant differences in time to optimum view of
the cords or time to intubate between the 1st and 5th intubations for
either device. Intubating conditions were similar for both devices.

Conclusion

The learning curve associated with infant GlideScope®

laryngoscopy and intubation by resident’s novice to infant airway management seems to be flat and identical to that with direct laryngoscopy.

GlideScope Use in Routine Clinical Practice

                                                                    Anesthesiology, V 114 • No 1 34-41 

Reported Results:

GlideScope use was studied in the  Oregon Health and Science University, Portland  and also the University of Michigan , Ann Arbor where during the study period 71,570 endotracheal intubations were reviewed and there were 2,004 GlideScope applications .
Overall GlideScope success:                                    97% (1,944 / 2,004)
Primary GlideScope use success:                            98% (1,712 / 1,755)
Predictors of difficult DL  GlideScope success      96% (1,377 / 1,428)
GlideScope rescue after failed  DL                          94% (244 / 239)
GlideScope rescue after failed Fiberoptic scope     80% (8 / 100)

Complications:
    Minor - soft tissue injury                                                    1%      (21 / 2,004)
    Major 0.3 % - Pharyngeal, tracheal ,laryngeal injury    0.3%   (6 / 2,004)

Limitations:
    The GlideScope failure was associated with neck radiation, neck mass, or a surgical scar by the Aziz group study.

Comment:
This study is significant because the GlideScope was used in institutions where the use is taught on a regular basis and use as a rescue device is well established.  The ASA difficult airway algorithm is used and regularly taught as well. The use for failed FOB use is interesting because the FOB is widely regarded as the "Gold Standard" technology for difficult airway management.
The effectiveness shown in this excellent study supports the anecdotal information in the field where many users consider GlideScope 60 degree angle scopes to be the most effective rescue available for difficult airway management.

The use of video laryngoscopy as a first line with GlideScope has been practiced in many ED units and some ORs  and this practice is growing.

Caldiroli devised what he considered to be an optimal practice where the GlideScope was used according to a pre-application assessment using the El Ganzouri index. The reported results on 6,276 patients demonstrated  difficult GlideScope video laryngoscopy in only 0.14% or 14 patents. The predictive value was very high when EGRI was 0-6 . The other advantage of this strategy is that  regular use leads to very high skill levels among the anesthesiology team. The least optimal pattern of behaviour is when rescue tools are only used with unexpected difficult conditions where skills may be found to be wanting.

Reference:

1. Caldiroli  A new difficult airway algorithm based on the El Ganzouri Index GlideScope video laryngoscope. a new look for intubation. Minerva Anesthesiologica vol. 77 2011
2. El Ganzouri   Preoperative Airway Assessment: predictive value of a multivariate risk index. Anesth Analg 1996; 82;1197-2004.

            

Position Analysis for GlideScope Intubation

Recent SAM discussion -GlideScope Patient Positioning- how to Analyse.

What are the principles one needs to apply when assessing patient positioning with the highly angled video laryngoscope-GlideScope?

The GlideScope was designed to accept the patient anatomy and provide an airway view by positioning the camera in the pharynx viewing the glottis by lifting the tongue along its length without excessive lifting of the glottis itself. The inspection of Adnet's lateral view of MRI Airway images is instructive. The interception of the MA (mouth angle) and the PA (pharyngeal angle) produces an angle which I have termed the Alpha Angle which is 60 degrees. The GlideScope exploits this underlying information to produce 99.9% usable airway views without excessive lifting of the glottic complex.

Obesity

The obese patient has several features that may make GlideScope laryngoscopy difficult. The first of these is excessive fat deposits in the region of the pharynx. Usually this fat does not prevent viewing as one stays in the midline and can do some extra lifting of the tongue.

There is often a prominent Buffalo Hump fat deposit in the inter scapular region which has the effect of elevating the thorax in a way that allows the neck to extend with consequent head position more posterior. This posterior position of the neck may increase the angle created by the LA (laryngeal angle) and the PA (pharyngeal angle) and make passage of the endotracheal  tube more challenging. Placement of a doughnut to pillow under the head to produce a neutral neck angle is probably helpful in most patients to restore normality.

The other consideration that may be useful is to place the patient in a moderate reverse Trendelenberg position, on some form of ramping or table flexion that reduces the work of breathing while intubation is being anticipated. This must be combined with consideration of venous return and cardiovascular status.

Excessive sniffing position may change the angles of the airway adversely so if one does this one must be ready to adjust the neck to a neutral position if tube advancement is an issue

Normal Patient

The normal anatomy accommodates the GlideScope in the neutral neck position which keeps the MA, LA, and PA angles in usual relationship and as far as we know now is the recommended position. Studies on this topic may shed more light in the future.

The factors leading to difficulty advancing the endotracheal tube when using the GlideScope were identified in 2001 when initial studies were done. These are:

1. deep insertion of the GlideScope

2. excessive lifting of the glottis- one must lift the tongue with addition of a slight 2 finger lifting of the blade tip _just enough to give a grade 2 view.

3. Slight withdrawal of the blade will allow the glottic complex to resume its normal position which is adjacent to the posterior pharyngeal wall. This position favors intubation.

Management of the Super Obese- Unofficial SAM BMI Record- 163.

 Awake Intubation .

       In 2007 This 945 lb. case was reported by Cleveland Clinic Anesthesiologists Dr. John Doyle and Dr. Andrew Zura , Rakmachandran M ,Lin J, Cyinski J B, Parker B, Marks T, Feldman M, Lorenz RR  who appear to have the record for a published and peer reviewed case of Super Obese Airway management.

       This massive 22 year old individual required a tracheostomy for hypercarbia with failed  CPAP therapy was reported in the Journal of Clinical Anesthesia : 2007;19:367-369. 

       The management was carried out by an awake approach with , first an attempt at awake flexible Fiberoptic endotracheal tube placement , which failed to achieve the safe advancement of the endotracheal tube. This failure was caused by poor patient compliance and epistaxis. Then a size 5 Proseal Laryngeal Mask Airway was placed successfully and provided a passage way for a Flexible scope passage with an Aintree exchange catheter loaded on to it. The flexible scope was then removed and the 7.5 mm I.D. endotracheal tube  was then passed over the Aintree catheter by a "railroading" technique. 

       The GlideScope was not attempted in this individual so its possible utility is not determined. GlideScope use in Massive obesity has been reported by Dr. John Doyle elsewhere .

GlideScope Obesity Record BMI - 125 . Report from SAM FORUM Feb 13, 2015

GlideScope Intubation of Patient with BMI 125 - Denver Colorado

The SAM forum has recently had an unofficial challenge series describing High BMI individuals treated by SAM members. The Patients included :

1. The Key Case posted by Felipe Urdaneta was a Thyroidectomy case booked for a Thyroidectomy , possible neck dissection. This patient was ultimately  intubated using an awake flexible scope technique . The patient was extubated with Remifentanil drip sedation. The patient became confused enough to break the special service Bariatric bed but survived the event.

2. Richard Shockley recollected a case with a BMI 99.

3. The Record Case so far was reported by Sara Cheng MD , Denver Colorado.

Sara was in her first Post Residency year, when she was called to MICU for a stat intubation at 4AM. The super obese patient  had deteriorated under BiPap to a PACO 2  of  100 . 

This hypercapnia was causing CO2 Narcosis.

The BMI calculated to be 125.

The patient was intubated sitting up with Sara Cheng in front of the patient using a GlideScope 

No additional Medication was used.

This technique has been called the Tomahawk Procedure .

GlideScope "Tomahawk"  Technique

1. Patient in a sitting position,  laying on the side , or supine.
2. Pacey Topicalization Technique ---2% Lidocaine Gel / 2% Lidocaine liquid mixture. 3 way stopcock and 2- 10 cc syringes used to mix 15 cc total volume with some air to create foam.
3. Deliver Foam to the oropharynx where it will spread throughout the pharynx.
4. Invert the GlideScope screen so that right and left sides are correct.
5. Hold the GlideScope like a Tomahawk in the Right hand
6. Use a Verathon rigid stylet and an appropriate size tube- consider a Parker tube if available.
7. Introduce the GlideScope but, as always do not insert it too far or lift too vigorously.
8. Introduce the ETT and extract the stylet as the tube tip passes the cords .