Airway Management

Dr. Paul LabanaEmergency Medicine Consultant 12th February 2014

Case presentation

Assessment

Clinical features

Decision making algorithms

Equipment used

Overview

35 yr male is t/f to TWH with 5% PT burns to face, neck,

anterior chest after methylated spirits explodes from fire

PMHx – Type I DM, hypercholesterolaemia, hypertension,

smoker, occasional EtOH

Coversyl +, Amlodipine, Atorvastatin, Protophane, Actrapid

Allergic to penicillin

On examination: A, B, C currently stable pain under control, covered in dressings with only nose showing, blisters/swelling around lips/oropharynx

Starts to complain of SOB – vitals OK on high flow oxygen

What would you do next?

O/E facial swelling (but not in mouth), blisters on lips, nasal

hair singed Decision for definitive airway Pre-ox, cricoid pressure, propofol, suxamethonium Initially grade 2 view with McCoy blade + stylet ETT dislodged on removing stylet (paraffin all over face/gloves making jaw thrust impossible) Bag & Mask ventilation Sux. wearing off, biting through guedel, desat 55% at

lowest Further propofol, sux – Fastrach inserted #5 but big

leak Replaced with classic – good ventilation Pt. became bradycardic – atropine 300 mcg Further attempts at ETT with swollen tongue,

eventually intubated as confirmed by ETCO2

Progress

Continued to improve over next 5 days

Successfully extubated with nil stridor and good ABG’s

D/C to burns unit

Later d/c and was well

General Principles of Airway Management

Aims of management Maintain oxygenation, prevent hypercarbia Minimise airway trauma (i.e. minimal instrumentation)

3 main scenarios Anticipated difficult airway e.g. burns Unanticipated difficult airway Facial/neck trauma

Airway Management

Anaesthetic history (if at all available) History

Previous difficult intubation/ventilation Congenital syndromes

Down’s syndrome, large tongue, Atlanto-axial instability Nasal polyps, neck and TMJ problems, loose

teeth Examination

Facial hair Teeth: protruding or long upper incisors, prominent

overbite Mouth opening (need at least 3-4 cm between

incisors) High arched, narrow palate Mandibular protrusion (upper lip bite) Neck mobility and masses Thyromental distance (>6cm normal)

Methods of assessment

General Habitus Ethnic differences: anterior larynx, small jaw, protruberant teeth Pregnant: Large breasts, mucosal hypervascularity, reduced oxygen reservoir

with risk of desaturation

Congenital syndromes: Downs’ syndrome, Goldenhaar, Pierre-Robin, Achondroplasia

Orofacial trauma - (patient in C-spine collar?) Nose

Nasal polyps, deviated septum, hypervascularity in pregnancy Mouth

Small or restricted mouth opening, restricting laryngoscope passage Teeth

Protruberant incisors, loose teeth (potential airway obstruction if knocked out) Tongue

Macroglossia (Down’s Syndrome, Acromegaly) Jaw (incl. TMJ)

Small or recessive jaw, previous TMJ surgery causing restriction may impede laryngoscopic view Neck

Bullneck, previous surgery/tracheostomy Reduced ROM: Ankylosing Spondylitis, previous fusion, rheumatoid instability

Environment Lack of equipment, skilled assistant

Examination

Relative Tongue/Pharyngeal size Modified Mallampati classification gives variable

prediction of airway difficulty (rarely possible in emergency setting) I: Soft Palate, Fauces, Uvula, Ant + Post pillars II: Soft palate, Fauces, Uvula III: Soft palate, base of uvula IV: Hard palate only

Performed with patient seated, head in neutral position, mouth open to widest extent and tongue maximally protruded without phonation

Correlation with Cormack-Lehane grading: Class I: Grade I view 99-100% of the time Class IV: Grade III or IV view 100% of the time Class II and III are poor predictors

The Mallampati classification is a simple scoring system that relates the amount of mouth opening to the size of the tongue, and provides an estimate of space available for oral intubation by direct laryngoscopy. According to the Mallampati scale, class one is present when the soft palate, uvula, and pillars are visible, class two when the soft palate and uvula are visible, class three when the soft palate and only the base of the uvula are visible, and class four when only the hard palate is visible.

The Cormack-Lehane system for grading laryngoscopic view at

intubation

Difficult ventilation

Pregnant Increased breast tissue with reduced chest

compliance Obese

As above, plus increased pharyngeal tissue with increased upper airway resistance OSA / Snorers Beard

Difficult to achieve seal with mask Edentulous

Difficult to achieve seal with mask

Neck mobility and correct positioning

1. Bad : neutral position

2. Better : C6/C7 flexion

3. Best : Flexion at C6/C7 Extension at C1/C2 (~ 35º) “Sniffing the morning air…”

Complications of difficult airway access Hypoxaemia Soft tissue injury of the airway Increased gastric

aspiration/regurgitation risk Haemodynamic stress of repeated

laryngoscopic stress attempts Unnecessary tracheostomy Tooth damage

Facial/Neck Trauma & Burns

Ensure senior anaesthetic/surgical help present Early consideration of intubation/surgical airway essential Childhood infections causing partial obstruction generally

approached via gentle inhalational induction therefore call anaesthetics a.s.a.p.

Can return to spontaneous breathing if laryngoscopic view poor, or offer option of FOB (bearing in mind it may occlude already narrow lumen) In cases of marked deformed anatomy, tracheostomy is

generally the definitive management

Open vs percutaneous dilational: No major difference in outcome, PDT associated with reduced risk of pneumomediastinum/bleeding

May be performed under local anaesthetic (ketamine has also been described)

LEMONL ook (facies, anatomy, obesity etc.)

E valuate 3-3-2 (see below)

M allampati

O bstruction (mass, infection, SOL)

N eck mobility (“sniffing morning air”)

Preparation for intubation

P repare patient & drugs & P ositioningE nd-tidal CO2

M ask (& bag connected to O2 AND ON)

A djuncts (LMA/Guedel/Nasopharyngeal)

I ntroducerL aryngoscopeS uction (turned on at head of bed)

Failed Intubation

Macintosh (standard used on airway trolleys) McCoy

Levered mobile tip allowing elevation of epiglottis Potentially reduces C-L grade by one Useful in cervical collar patients, anterior larynx

Kessel Modified Macintosh blade with increased handle-blade angle (110˚):

easier insertion in large-breasted (pregnant) women Miller

Straight blade with curved tip for elevating epiglottis Thinner profile: easier insertion in small-mouth opening pts

Huffman Macintosh blade with 30 or 80˚ refractive prism towards larynx:

allows indirect laryngoscopy

Laryngoscopes

Gum elastic bougie (Eschmann tracheal tube introducer) 60cm, 15F (adults)/10F (children), Coude tip. Introduced in the

1970’s Portex reusable bougies most common. Disposable available

but reported to have reduced success with intubation (?due to less malleable texture)

Used in conjunction with laryngoscope to facilitate ETT passage where laryngeal inlet is incompletely visualised (or can be inserted blindly)

Advantages are Longer compared with stylets Malleable, angled tip - ideally at 60˚ to capture

tracheal “clicks” Flexible yet firm enough to have ETT railroaded over it

Signs that bougie is endotracheal (therefore safe to railroad ETT)

“Clicks” from tracheal rings Hold-up/Resistance at ~40cm (within bronchial tree) Coughing

Intubation Aides

Airway exchange catheters Functions as bougie, but with central lumen allowing

ongoing oxygenation between intubation attempts Internal diameter varies between 3.7mm (Cook exchange

catheters) to 4.7mm (Aintree airway catheters) NICE paper demonstrating use in conjunction with

LMA and fibreoptic bronchoscope: Low-skill fibreoptic intubation: use of the Aintree catheter with the classic LMA.

Anaesthesia 2005; 60: 915-920 Stylet

Malleable, single use stylets used to shape ETT, allowing for easier

passage into anterior larynxes BURP/2 person intubation

Intubation Aides 2

Most are disposable Once inserted, the mask is bounded by:

Tip at level of inferior constrictor Sides abutting piriform fossae Top against base of tongue

Provides airway support rather than definitive airway Valuable tool in rescue “can’t intubate, can’t mask ventilate”

situations Serves as a conduit for endotracheal intubation

Theoretically #4 can fit a 5.5 ETT, but clumsy fit at best Narrowest point is at LMA connector - ETT cuff may be torn here Length of LMA tube may lead to improper depth of ETT placement Very difficult to remove LMA once ETT is placed

Gum-elastic bougie/Fibreoptic bronchoscope may be fed down lumen to facilitate endotracheal intubation and confirm position

Bronchoscopic port connector allows simultaneous ventilation & FOB

Laryngeal Mask Airway

Cook Kit (Seldinger technique)

Seldinger technique safer than blind approach

Aspirate air with the needle and syringe to check placement, cut with scalpel

Remove syringe, insert wire into needle, remove needle

Thread dilator with airway already loaded onto wire

Remove wire

Needle cricothyroidotomy

Oxygenation NOT ventilation Use 14 g cannula with syringe attached, once

aspirating air, insert sheath and remove needle Connect a 3 way valve to sheath and to oxygen

tubing 15 L/min oxygen for 1 sec followed by 4 secs

expiration phase Approximately 45 mins to get definitive airway

Cricothyroid membrane between thyroid and cricoid cartilage

Locate hyoid with thumb & index finger and middle finger will fall on correct area (1-1.5 cm below)

Standard Surgical Airway

Equipment always available BUT need most senior help available

Vertical incision in skin of neck Transverse incision of cricothyroid

membrane Artery forceps/finger to open airway Insert cuffed ETT 6.0 into trachea

Surgical Airway

Questions ???