Dissecting The ASA Difficult Airway Algorithm-Part 1

     The 2013 version of the ASA Difficult Airway Algorithm was the second major upgrade that was carried out to recognize changes in accepted practice and available technology.

     Dr Archie Brain went through a series of prototypes of LMA to achieve transition of the mask from the mouth and nose area in the Pharynx close to the Laryngeal opening.
The recognition of the utility of the LMA device in rescue of patients who were either difficult laryngoscopy, difficult intubation, or cannot intubate -cannot ventilate , was an important event that allowed practitioners to transition to a totally different technique from multiple direct laryngoscopy attempts . Thus the 2003 Algorithm identified the use of the LMA at several stages including first use and rescue .

     The 2013 Algorithm changes Identified Video Laryngoscopy as a new and accepted asset in first use as well as rescue. The advent of the highly Angled 60 degree GlideScope, invented by Dr John Pacey , resulted in  widespread use of a video camera enabled laryngoscope that transferred the view point from the oral opening to a position in the pharynx looking at the larynx. The geometry of this device was uniquely effective. Now the Algorithm speaks of considering Video Laryngoscopy as a first choice , as a rescue device, and in conjunction with extubation strategies. 

            
                                                    ASA DIFFICULT AIRWAY ALGORITHM- 2013 MODIFICATION 
                                                                            Introductory Considerations

    1. Assess the likelihood and clinical impact of basic management problems: 
• Difficulty with patient cooperation or consent

• Difficult mask ventilation
• Difficult supraglottic airway placement
• Difficult laryngoscopy
• Difficult intubation
• Difficult surgical airway access

2. Actively pursue opportunities to deliver supplemental oxygen throughout the process of difficult airway management.

3. Consider the relative merits and feasibility of basic management choices:
• Awake intubation vs. intubation after induction of general anesthesia
• Non-invasive technique vs. invasive techniques for the initial approach to intubation • Video-assisted laryngoscopy as an initial approach to intubation
• Preservation vs. ablation of spontaneous ventilation 

4. Develop primary and alternative strategies:

                                                                         Dr Pacey's Comment

                                         Firstly  begin by considering the Items in Checklist 1.

• Difficulty with Patient cooperation or consent clearly complicates any evaluation , premedication, pre oxygenation, intubation (may reduce options for example for Flexible awake strategies).             Evaluate?
• Mask Ventilation difficulty is a combination of caregiver skill set , patient features like beards , facial architecture , and other equipment issues .                                                                                    Evaluate?
• This is a new concept "Difficult SGA placement" can be due to mouth size ,neck fixation, radiation , prior surgery and can result in failure to protect the airway or ventilate.                                                 Evaluate?
• Difficult Laryngoscopy with ?DL, ?VL, Radiation could for example cause this. The term is importantly separated out from difficult intubation because they are separate problems to be considered .    Evaluate?
• Difficult Intubation can occur for example with DL or VL if the operator is an infrequent or poorly trained and experienced incubator or if , for example, there is a physical mass in or around the larynx    Evaluate?
• Difficult Surgical Airway access may be caused by many factors , obesity, burns, lack of training , to mention a few . Will you want to call surgical help in advance or place a guide wire in the neck? Evaluate?

Should a checklist be printed  and used as a guide? perhaps but the main point is to separate out these issues and be sure to consider them in the plan. A written checklist may have the effect of bringing up the performance of the less experienced and in this way affecting the quality of care given.

In the next post we will work our way down the ASA Algorithm into items 2,3,4.

Ron Walls Airway World and Emergency Medicine Airway Updates

Airway Site  and Airway World
Those who are keen to follow updates in Airway Science would do well to be cognizant of the work of Harvard Professor Ron Walls , Chairman of Emergency Medicine  at Women's and Brigham Hospital , Boston. Ron is w recognized leader in the evolution of airway science and was an early and strong advocate of the benefits of the 60 degree angled GlideScope Video laryngoscope as early as 2002.
The remarkable changes seen in airway management have been taught to hundreds of Anesthesiologists, ICU , and Emergency Medicine  USA. Ron has a history of academic rigour that is applied to all of his teachings and the latest manifestation of this is the Airway World Academic teaching platform that is affiliated with the  STRATUS SIMULATION CENTER , one of the oldest and seminal teaching Simulation centres in the world.
To sample the Airway World one can log on and learn as you go. One can be assured of the quality and rigour of the Science in my experience.

Quarterly Airway Management Research Update

Featuring Ron M. Walls, MD Professor & Chair, Department of Emergency Medicine Brigham & Women's Hospital, Harvard Medical School with Cheryl Lynn Horton, MD and Ali S. Raja, MD

                      GlideScope Superiority  for  patients with Neck abscesses of Dental Origin  and  reduced Mouth opening.

      The treatment of Neck infections , Epiglotitis, and Abscesses present a daunting challenge for the Anesthesiologist who must manage the toxic physiology at the same time as plan a method of Pain relief and anesthetic management. Relief of gross abcesses prior to anesthesia is always beneficial and can take the risk level down to some extent. Unfortunately drainage is usually not possible into the lumen  but can sometimes be accomplished via needle aspiration combined with imaging or external drainage. Extensive swelling and cellulitis cannot be managed this way. High doses of appropriate broad spectrum antibiotics are essential at first encounter.

     The Glidescope has been used effectively  for Epiglotittis. The risk of this entity is that pus will discharge unexpectedly or that in some other way control will be lost so management must be individualzed to control risk.

     Infections of Odontogenic origin associated with reduced mouth opening or trismus  present great risk for anesthesia and following observation that the 60 degree angle Glidescope Video laryngoscope was successful when used for failed Direct Laryngoscopy Schumann et. al. decided to test this phenomenon with a randomized study comparing patients whose care was started with DL versus those whose care was started with GlideScope 60 degree VL. 

    The results prove that in these high risk patients Glidescope intubation was clearly superior as reported here.

"Results. Intubation with the Glidescope was always successful, while conventional intubation failed in 17 out of 50 patients (P,0.0001). In all patients in whom conventional tracheal intubation failed, a subsequent attempt with the Glidescope was successful. The view at the glottis (according to Cormack and Lehane; P,0.0001), intubation duration [34 s (CI 27–41) vs 67 s (CI 52–82), mean (95% confidence interval); P1⁄40.0001], and need for supporting manoeuvres (P,0.0001) were significantly different. The inter-incisor distance improved overall with induction of anaesthesia from 2.0 cm (CI 1.8–2.2) to 2.6 cm (CI 2.3–2.9; P,0.0001) and was correlated with the duration of symptoms.

Conclusions. In patients with odentogenous abscesses, the use of a Glidescope laryngoscope was associated with significantly faster tracheal intubation, with a better view, fewer supporting manoeuvres, and a higher success rate than with a conventional laryngoscope. Improvement of the inter-incisor distance after induction of anaesthesia correlated with the duration of symptoms. "1.

Appendix:

1. Tracheal intubation in patients with odentogenous abscesses and reduced mouth opening
M. Schumann1, I. Biesler1, A. Borgers1, R. Pfortner2, C. Mohr2 and H. Groeben1*
1 Department of Anaesthesiology, Critical Care Medicine and Pain Therapy and 2 Department of Oral and Cranio-Maxillofacial Surgery, Kliniken Essen-Mitte, Henricistr. 92, Essen 45136, Germany .

British Journal of Anaesthesia 112 (2): 348–54 (2014) 

AdvanceAccesspublication26September2013 . doi:10.1093/bja/aet310 

2014 GlideScope Year " GLIDESCOPE AS A FIRST USE " CHOICE

                                                        Welcome All to 2014
                                                the year of the GLIDESCOPE.

     Let us take this opportunity to powerfully establish the use of GlideScope for all intubation related and other Airway Applications as a "FIRST USE CHOICE" for Airway.
Many leaders in Airway Management have called for and indeed used Video laryngoscopy as their first choice in airway management. The number of Emergency Departments, OR's and Clinics using GlideScope as the "first use choice" is rapidly increasing and the number of systems needed to support  this behaviour is increasing.
      Let us take this year to consolidate this trend and do a system upgrade for airway management. It is known that repeated use is the most important metric for getting over the "can see the airway but cannot introduce the Endotracheal tube".

                                                       Dr Pacey's Teaching

•     Use the 4 step approach  1. view mouth while you introduce the device slightly to left of midline  2. visualize the epiglottis then slightly lift the tip to see the airway 3. Watch the ETT pass into the mouth to avoid injury to Tonsils and Palate   4. Avoid going too deep and do a MINIMAL LIFT of the larynx while introducing the endotracheal tube by extracting the Verathon Stylet slowly.
• The Verathon Stylet is a powerful enabler for the GlideScope.
• When intubating keep the Glidescope back as far as possible to avoid excessive lifting of the Glottic Complex.

                           Stand by for exciting new improvements to the GlideScope in 2014.
                                                          Have a Great New Year!
                                                          Dr John Allen Pacey MD FRCSc
                                                          GlideScope and Aperture Inventor

Park - Glidescope Intubation During Uninterrupted CPR

    The concept and practice of  " intubation during  uninterrupted CPR"  was demonstrated by Dr Marvin Wayne during exploration of application of the Glidescope Ranger to a Whatcom County Fire Ambulance Service service area population published in 2010 (1). Many patients in this study were in fact CPR patients and on a few the compressions were noted on video to be continuous during the intubation.
   The confirmation study has now been published by SO Park (2) who has published a landmark study in 09/25/2013 Rescusitation wherein it was shown that Glidescope intubation can be easily carried out without interruption of CPR. The importance of this finding is that the debate about how to manage airway during resuscitation is vaulted to a new level by readily available Glidescope technology.
The 60 degree angle of the Glidescope is important in that it allows easy airway viewing during the intubation as will be noted when viewing real time intubations carried out  by Fire service care givers. The adoption of Glidescope Video Laryngoscopy can substantially change the current management of airways during CPR.


Reference:
1. 

Comparison of Traditional versus Video Laryngoscopy in Out-of-Hospital Tracheal Intubation

Authors: Wayne, Marvin A.; McDonnell, Mannix

Source: Prehospital Emergency Care, Volume 14, Number 2, June 2010 , pp. 278-282(5)

 Results. The average time to intubate in the VL group was 21 seconds (range 8---43 seconds) versus 42 seconds (range 28---90 seconds) in the TL group. The average number of attempts was 1.2 (range 1---3) in the VL group versus 2.3 (range 1---4) in the TL group. Successful intubation was 97% in the VL group versus 95% in the TL group. There were no unrecognized misplaced tubes in either group. For failed intubations, an alternative airway was successful in 99% of the VL group and 99% of the TL group. Maximum nonventilated time during any one intubation attempt was 37 seconds in the VL group and 55 seconds in the TL group. Conclusions. The numbers of attempts were significantly reduced in the VL group. This suggests that the use of VL has a positive effect on the number of attempts to achieve tracheal intubation.

2.

Feasibility of the video-laryngoscope (GlideScope) for endotracheal intubation during uninterrupted chest compressions in actual advanced life support: A clinical observational study in an urban emergency department 
Source: Resuscitation, 09/25/2013  

Park SO et al. – This is the first clinical trial to evaluate whether successful endotracheal intubation (ETI) using a video–laryngoscope (VL) (GlideScope) can be performed easily without chest compression interruptions during actual cardiopulmonary resuscitation (CPR) after brief VL training, regardless of the physicians’ levels of experience with successful ETI in the past. In a clinical setting, the use of a VL had a high success rate for the first ETI attempt with notably few chest compression interruptions, regardless of the physicians’ varying experience with successful ETI in the past.

SHANA Important New Airway Society for Head and Neck Anesthesiologists

                                 

                               

                                                 SHANA an important New Airway Society!
   The Society of Head and Neck Anesthesia has been created recently from a base at the University of Michigan Medical Centre in part due to the efforts of Dr David Healey , the founder , and a group of enthusiastic colleagues dedicated to the study and development of the considerable  intricacies of anesthesia in the area.

    The society is developing a new "Zero Fee" model that is expected to be popular in the future , especially in international arenas where the internet can be the principle vehicle of communication. The site is developing rapidly and contains a useful feature area for algorithms or protocols , a  library, and developing picture and video collection.

    There is very high level information currently posted on " Extubation Strategy" for example which has been pointed out recently as being a troublesome area in the post -operative area but more importantly in the ICU setting where care is driven by teams. UK NAP 4 Data shows clearly that Death and Brain damage are outcomes likely when Extubation is poorly planned or executed .

    Interesting posts are also available from Dr Anil Patel , for example , which teach the subtleties of sub Glottic stenosis management. The benefits of membership promise to be very instructive as the energy of the scientific team come on in full force.

 

Telemedicine Advance Teaching and Quality assurance

The advent of Telemedicine and its application to Airway is proceeding now with a series of experimental applications in US Army Afghanistan , Harbourview Hospital Helicopter Transport, Fort Sam Houston, Tucson Arizona and at Avera health in Sioux Falls South Dakota. 

The scene here is from the E Emergency 24/7 bunker at Avera Health where the central hospital team assists the smaller hospital ER team with decision support, and evacuation strategy as required.