A Difficult Airway Presentation1.2
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Transcript of A Difficult Airway Presentation1.2
The Difficult Airway
The clinical scenario when safe oxygenation and ventilation cannot be achieved in the desired way with the use of an individual’s usual practice
Difficult Intubation
Difficult Mask Ventilation
Difficult Intubation
Difficult Mask Ventilation
Difficult Supraglottic Airway
1:50Intubation
1:25Supraglottic
1:20MaskDifficult
Incidence in general population
1:20001:50Intubation
1:3001:25Supraglottic
1:6001:20MaskFailedDifficult
Incidence in general population
1:2000
1:50
1:50
1:6
Intubation
Pre-Hospital
1:3001:25Supraglottic
1:6001:20MaskFailedDifficult
Incidence in general population
Timmermann et al., 2006 Resuscitation 70:179-85 (1106 patients)
Trauma patients had highest incidence of difficult and failed
intubation
Difficult Mask Ventilation(DMV)
Degrees of Difficulty
1 Single person BVM with chin lift+/-jaw thrust
2 Above + OP or NP airway or both
3 Above plus assistant to squeeze bag or provide jaw thrust/face mask seal
4 Anaesthetist plus 2 assistants; one to squeeze bag and other to provide jaw thrust/face mask seal
Obese (BMI>26)BeardedElderly (>55)SnorersEndentulous
Male‘n’eckMallampati (grade 3 or 4)
Difficult Supraglottic Airway
Inability to open mouth more than 2.5cm(impossible if <2.0cm)
Intraoral/pharyngeal masses
Difficult Intubation
Look externally
Evaluate 3-3-2
Mallampati
Obstruction
Neck mobility
Look externally - trauma, limited mouth opening
Look externally
Evaluate 3-3-2 3 fingers between the teeth
3 fingers between the tip of the jaw and start of neck
2 fingers between the thyroid notchand floor of mandible
Look externally
Evaluate 3-3-2
Mallampati assessmentClass 1 - soft palate, fauces, uvula, & both anterior and
posterior pillars Class 2 - soft palate, fauces, and uvula Class 3 - soft palate and the base of the uvula Class 4 - soft palate is not visible
1 2
3 4
Look externally
Evaluate 3-3-2
Mallampati assessment
Obstruction - epiglottitis, peritonsillar abscess, trauma
Look externally
Evaluate 3-3-2
Mallampati assessment
Obstruction
Neck mobility - limited movement, cervical collar
Is LEMON useful?
Look externally Large incisors
Evaluate 3-3-2 Reduced mouth opening & reduced thyroid to floor of mouth distance
Mallampati assessmentObstruction Neck mobility
114 grade 1 29 grade 211 grade 3 2 grade 4
Reed et al., 2005 EMJ 22:99-102
2509 patientsUpper front teethPrevious Hx of difficult intubationMallampati >1Mouth opening <4cm
Diff intub (%) 0 2 4 8 17Risk factors 0 1 2 3 4
Eberhart et al., EJA March 2010
But does it all really matter?
When do we intubate?
Are all of our intubations ‘difficult’?
Blood/vomitus in airway
Limited mouth opening
Facial/neck trauma
C-Spine precautions
Preoxygenation
Preoxygenation with Non-Invasive Ventilation in critically ill patients is better than BVM preoxygenation
Baillard et al., 2006 Am J Respir Crit Care Med 174:171-7
Baillard et al., 2006 Am J Respir Crit Care Med 174:171-7
NIV - pressure support to obtain an expired tidal volume of 7–10 ml/kg with a PEEP of 5 cm H2O for 3 minutes
Control – BVM with 15 L/min oxygen. Patients were allowed to breath spontaneously with occasional assistance
Preoxygenation of morbidly obese patients at 25° head up is better
than supine
Dixon et al., 2005 Anesthesiology 102:1110-5
Time to reach an SpO2 of 92% in morbidly obese patients
Head up 25° = 201 ± 56 s
Supine = 155 ± 70 s (p=0.02)
Dixon et al., 2005 Anesthesiology 102:1110-5
Better gas exchange by
reducing atelectasis
reducing V/Q mismatch
less reduced FRC
Dixon et al., 2005 Anesthesiology 102:1110-5
You have a look and can’t see anything
30 second drills Change operator position Change patient position (small pad under head with
neck in neutral position) Release cricoid and use bi-manual laryngoscopy Use better suction where secretions or blood block
view Laryngoscope can be inserted deeply and slowly
withdrawn until identifiable anatomy is seen Consider changing laryngoscope blade size or type Consider changing operator
Six variables to correct
Experienced practitioner No significant muscle tone Optimal position Blade length Blade type Use of laryngeal manipulation
Benumof 1994 Canadian Journal of Anaesthesia 41:361-5
Posture
The novices tended to crouch, head closer to the mouth, elbow more flexed and forearm further from the horizontal.
Matthews et al., 1998 Anaesthesia 53:331-4
The novices tended to crouch, head closer to the mouth, elbow more flexed and forearm further from the horizontal.
The trained subjects tended to stand back, elbow less flexed and forearm close to or even below the horizontal.
Matthews et al., 1998 Anaesthesia 53:331-4
The more experienced group levered less,with signifcantly lower laryngoscope handle angles (C)
Eye-to- laryngoscope distances (D) were greater in the more experienced group
Walker 2002 Br J Anaesth 89:772-4
Tesler et al., 2003 Resuscitation 56:83-9
Tesler et al., 2003 Resuscitation 56:83-9
Tesler et al., 2003 Resuscitation 56:83-9
Robinson et al., 2004 Air Med Journal 23:40-3
Position
Brodsky et al., 2003 Anesthesia and Analgesia 96:1841-2
Manual In-Line Stabilisation
MILS Does not limit cervical movement with
jaw thrust and laryngoscopy Worsens laryngeal view which prolongs
intubation attempt1
Increases pressures applied by the laryngoscope blade during laryngoscopy2
1 Thiboutot et al., 2009 Can J Anaesth 56:412-82 Santoni et al., 2009 Anesthesiology 110:6-7
It is prudent for clinicians to use manual in-line stabilization
when it does not hinder intubation attempts
Manoach and Paladino 2007 Ann Emerg Medicine 50:236-45
Cricoid Pressure
An Essay on the Recovery of the Apparently Drowned
"the restoring of the action of the lungs to be of the very first importance in all our attempts to recover the apparently dead." In addition, a description of pressure on the front of the neck as follows to "prevent the air passing into the stomach instead of entering the lungs."
Royal Humane Society, London: Silver Medal Winner (1788) Charles Kite of Gravesend
Sellick 1961 The Lancet 278 7199:404-6
Cricoid Pressure
Fails to prevent aspiration Reduces lower oesophageal sphincter pressure May prevent gastric insufflation during mask
ventilation Makes ventilation more difficult Causes lateral displacement and/or incomplete
obstruction of oesophagus Makes LMA insertion and ventilation more difficult May worsen laryngeal view May cause significant movements of cervical spine Is often applied incorrectly
Ellis et al., 2007 Annals Emerg Med 50:653-5
Cricoid pressure entered medical practice on a limited evidence base but with common sense supporting its use.
Ellis et al., 2007 Annals Emerg Med 50:653-5
Given that the risks of cricoid pressure worsening laryngeal view and reducing airway patency have been well described, we recommend that the removal of cricoid pressure be an immediate consideration if there is any difficulty either intubating or ventilating the ED patient.
Ellis et al., 2007 Annals Emerg Med 50:653-5
Given that the risks of cricoid pressure worsening laryngeal view and reducing airway patency have been well described, we recommend that the removal of cricoid pressure be an immediate consideration if there is any difficulty either intubating or ventilating the ED patient.
BURP?
Anaes Analgesia 1997:84:419-21
OELM or Bimanual Laryngoscopy
Percentage ofcases withimproved view
Cricoid 52%
BURP 54%
Bimanual 89%
Annals Emerg Med 2006:47;548-55
Prospective observational study Effects of cricoid pressure and laryngeal manipulation on laryngeal view in London HEMS
402 patients 98.8% patients intubated on the first or second attempt. In 61 intubations the larynx required manipulation.
Cricoid pressure removed in 22 - view improved in 50%.Bimanual manipulation used in 25 – view improved in 60%. BURP used in 14 - view improved in 64%.
Two patients regurgitated when cricoid pressure was released.
Harris et al., Resuscitation epub 2010
Cook 2000 Anaesthesia 55:274-9
Cook 2000 Anaesthesia 55:274-9
Bougie
Fibreoptic
Levitan et al., 1998 Acad Emerg Med 5:919-23
Bougie or stylet?
The gum elastic bougie is superior to the stylet for a simulated difficult intubation
Gataure et al, Anaesthesia 1996 51:935-8
Gataure et al, Anaesthesia 1996 51:935-8
Stylet - intubation was difficult and needed more time, especially when glottic opening was not
visible
Bougie - duration and ease of intubation was not influenced by
laryngeal view Noguchi et al., 2003 Can J Anaesth 50:712-7
When is a bougie not a bougie?
When it’s a tracheal tube introducer
BMJ 1949; 1:28
How do I know the bougie is in the trachea?
Clicks
Distal hold-up
Coughing
ClicksTip of bougie touches the tracheal
cartilages
Distal hold-upTip is touching the carina (approx 40cm)
CoughingMuscle relaxation is incomplete
Clicks – 90%
Distal hold-up – 100%
Kidd et al., 1988 Anaesthesia 43:437-8
Hodzovic et al., Anaesthesia 2004 59:811-6
Hodzovic et al., Anaesthesia 2004 59:811-6
Pre-hospital use of bougie
1442 pre-hospital intubations over 30 months
41 patients (3%) required a bougie
Bougie successful in 33 cases (78%)
8 patients required a second technique
Jabre et al., 2005 Am J Emerg Med 23:552-5
Laryngoscope Blades
Best results for intubation were obtained with the Macintosh and
the McCoy
A good laryngeal view does not equate with ease of intubation
Arino et al., 2003 Can J Anaesth 50:501-6
Size 4 English Macintosh performed the best at all insertion
depths
Yardeni et al., 2002 Acta Anaes Scand 46:1003-9
Other tricks
Left Molar Approach
Yamamoto et al., 2000 Anesthesiology 92:70-4
The left molar approach reduces the distance from the patient's teeth to larynx
and prevents intrusion of maxillary structures into the line of view.
Although it may offer advantages in terms of laryngoscopic view, there can be
difficulty in the insertion of the tracheal tube.
Cuvas et al., 2009 J Anesth 23:36-40
Failed intubation
3-4 attempts with some of the manoeuvres described
Declare a failed intubation Maintain cricoid Insert oral airway and ventilate with 100% O2 If ventilation difficult, try LMA; if still no ventilation,
and if laryngospasm excluded use crico-thyroid puncture
insanity (n) [in-san-i-tee] : doing the same thing over and
over again and expecting different results
Albert Einstein, (attributed) US (German-born) physicist (1879 - 1955)
LMA and Cricoid Pressure
The LMA is indicated in the known or difficult airway situation
The clinical record of the LMA in the CICV situation is excellent
Prehospital use of the ProSeal LMA
Successful use in 3 cases of failed intubation
PolytraumaBurns
Maxillofacial Trauma
Grier at al., 2009 Resuscitation 80:138-41
Insertion technique
Bougie inserted under direct vision into oesophagus
ProSeal railroaded over bougie
Howarth et al., 2002 Anaes Int Care 30:624-7
Intubating LMA (Fastrach) also been used successfully in
prehospital difficult-to-manage airways
Timmermann 2007 BJA 99:286-91
Pre-hospital resuscitation using the iGEL.
Thomas M, Benger J.
Resuscitation. 2009 80(12) 1437
Rapid sequence airway (RSA) with a LMA Supreme is quicker to
‘secure’ the airway (with less hypoxia) compared to a RSI in a simulated difficult trauma airway.
Southard et al., 2010 Resuscitation 81(5) 576-8
Confirmation of correct tube placement
Direct visualisation Auscultation for breath sounds Chest movement Feel of reservoir bag
CO2 detectors
Oesophageal detectors: withdraw air freely from trachea but the oesophagus will collapse
False negative
Equipment failure Disconnection Kinked gas sampling tube Kinked tracheal tube Severe airway obstruction Poor pulmonary perfusion
False positive
Tube in oesophagus after exhaled gases forced into stomach
Tube in oesophagus after fizzy drinks
Distal end of tube in pharynx
Gadgets
Video Laryngoscopes(VLEs)
Van Zundert et al., 2009 Anesthesia and Analgesia109: 825-31
Van Zundert et al., 2009 Anesthesia and Analgesia109: 825-31
Van Zundert et al., 2009 Anesthesia and Analgesia109: 825-31
Although VLSs offer several advantages........a good laryngeal view does not guarantee easy or successful tracheal tube insertion.
We recommend that the geometry of VLSs, including blade design, should be studied in more detail.
Van Zundert et al., 2009 Anesthesia and Analgesia109: 825-31
Indirect Laryngoscopes with tracheal tube conduit
Airtraq2006 – 4
2007 – 192008 – 182009 – 22
2010 – 20+
Airway Scope2006 – 1
2007 – 202008 – 222009 – 18
2010 – 13+
54 paramedics used each device (Macintosh laryngoscope, Airtraq and Airway Scope) in a random
order on three manikins
standard airway - no manipulation of the manikin’s airway
difficult airway - set to simulate grade 3 laryngoscopy view
sitting manikin - no manipulation of the airway
In the difficult airway manikin.....
Tracheal intubation with the AWS was more successful and faster than the Airtraq
and Macintosh laryngoscopes
Dogma is the established belief or doctrine held by a religion, ideology or any kind of organization: it is authoritative and not to be disputed, doubted or diverged from