airway Flashcards
NAP 4 questions
what type of airway device and how often
how often do major complications leading to serious harm occur in icu, ed, anaesthetics
what is the nature and what can we learn
themes relevant to critical care
1 in 4 events in icu or ed and more likely to lead to permanent harm or death
- 61% on icu
failure to use capnography on ice contributed to more than 70% deaths
displaced ett and trachea on icu greatest morbidity and mortality
poor airway assessment contributed to poor outcomes
failure to plan for failure
multiple repeated attempts at intubation
failure to correctly interpret capnography
1/3 events on extubations
limitations of airway assessment in critically ill
- reduced patient capacity to comply
- urgency
- patient distress
- oxygen dependency
human factors - cognitive overload, inadequate lighting, availability of clinical records, variable expertise
Airway assessments
Mallampati score
collateral / previous anaesthetics
MACOCHA - validated in ICU
- Mallampati 3-4
- osA
- cervical spine immobility
- mouth Opening < 3cm
- coma GCS < 11
- Hypoxaemia < 80%
- Non-anaesthetist
Nasendoscopy / CT
Increase difficulty in ICU patients
Pathology - ENT malignancy, epiglottis, supraglottitis, facial trauma, tracheostomy
altered physiology - hypoxia, sepsis
environment - ergonomics not set up for airway, crowding equipment, variable skills of assistants
intubation - equipment, monitoring, large tube
Positive influence on intubations
Human factors
- use of checklist
- role allocation
- ODP / trained assistant
Procedure
- Plan A - D
- VL first line
- positioning / location
- pre-oxygenated with HFNO / CPAP
- appropriate use of RSI / DSI
situations which may lead to airway complications
- intubation
- extubation
- tracheal tube change
- tracheostomy insertion
- routine care - rolling etc - airway occlusion dislodgment, malfunction
stridor
harsh sound caused by partial upper airway occlusion leading to turbulent air flow
- inspiratory - extra-thoracic airway obstruction (at or above VCs)
- expiratory - intra-thoracic airway obstruction (below VCs)
- biphasic
Stertor - partial obstruction at level of pharynx / oropharynx
I critical care
- anaphylaxis
- trauma
- infection
- laryngeal dysfunction from airway devices
post-extubation stridor
- laryngospasm, arytenoid cartilage dislocation, laryngeal nerve palsy, granulation tissue, laryngeal oedema
- risk factors for laryngeal oedema - ENT infection,, prolonged intubation, large ETT, high cuff pressure, difficult intubation, obesity
cuff leak test
provide information about laryngeal swelling
deflating cuff allows gas to escape around
auditory detection or measure on ventilator
- record insp / exp Vt
- deflate cuff
- record exp Vt over 6 breathing cycles, average lowest 3
- cuff leak volume = inspiratory Vt pre test -(average exp Vt)
- 110ml / 10-15% acceptable
Mx post extubation stridor
respiratory distress likely to require emergency re-intubation
rescue maneouvres - Iv steroid, nebuliser adrenaline, HFNO / CPAP and plan for reintubation
Severe croup
- FiO2 > 40%
- lethargy / reduced GCS
- minimal response to nebulised adrenaline/ steroids
- signs of respiratory distress
Management of stridor in children
- avoid distress e.g. cannulas, observations
- nebulised adrenaline 0.5ml/kg 1:1000, oral dexamethasone 0.6mg/kg, nebulised budesonide
- treat underlying cause e.g. antibiotics
- early escalation to anaesthetics
intubation - inhaled induction vs IV
- theatre environment
- checklist
- ENT
- rigid bronch / tracheostomy
- senior operated
- VL
- Range of ETT sizes
Anaphylaxis definition
Serious systemic hypersensitivity reaction
usually rapid in onset
may cause death
Diagnosis highly likely when
- acute onset skin / mucosal sx + 1 of
- respiratory compromise
- hyopitension
- GI symptoms
Acute onset of any of the following after exposure to known, highly probably allergen
- hypotension - sBP > 30% decrease in baseline
- bronchospasm
- laryngeal involvement
WAO systemic allergic reaction classification
Gr 1 - 1 organ system (cutaneous / URT / conjunctival / other)
Gr 2 - > 2 organ systems
Gr 3 - lower airway - mild bronchospasm, abdo cramps, any features from 1-2
Gr 4 - severe bronchospasm, stridor
Gr 5 - resp failure, CVS collapse, LOC
causes of anaphylaxis
Food - nuts, fruits
insect stings
drugs
Nap6 - ABX (penicillin, teicoplanin), NMBD, chlorehxidine
pathophysiology of anaphylactic shock
- mast cell degranulation –> histamine
- distributive shock
- vasodilation
- capillary leak
- reduced venous return / CO / coronary perfusion
Mx anaphylaxis
A-E
remove prcipitant
adrenaline IM and repeat after 4mins
high flow O2
crystalloid bolus
refractory if no improvement after 2 doses adrenaline - adrenaline infusion. 5 minutely IM until ready. fluid boluses.
peripheral adrenaline - 1mg in 100ml (10mcg/ml) 1ml/kg/hr start and titrate
2nd line - NA, VP, metaraminol
ECMO
adrenaline dosing
- IV 10-100mcg IV
- IM 0.5ml 1:1000 (1mg/ml) i.e. 500mch
- 6-12 - 0.3ml
- 6mo - 6yrs - 0.15ml
- < 6mo 0.1ml
steroid / antihistamine de-emphasised
severe bronchospasm - nebulised dilators, IV salbutamol
anaphylaxis follow up
- education
- speclialist allergy clinic
- adrenaline inector
- yellow card / local reporting
- mast cell trytase - early as possible, 1-2hrs, > 24hrs
anaphylaxis minmics
angioedema= swelling od subdermis, face, airway
causes of angioedema + urticaria
chronic inducible urticaria - idiopathic / heat / cold
autoimmune = SLE
systemic mastocytosis
angiodema without urticaria
- idpatgic
- autoimmune
- hereditary angiodema - C1 esterase inhibitor deficiency
- ACE-1
drug related
- insect bites
heridatory angiodema - recurrent episodes of angiodema, unresponsive to adrenaline, no clear allergen
- C1 esterase inhibitor concentrate
- kvllikrein inhitor
- FFP
Choking BLS
Adults
- encourage cough
- if ineffective - 5 back blows
- if ineffective 5 abdo thrusts
- alternate
- CPR if unresponsive
Infant
- head down prone on lap
- 5 back blows
- head down supine - 5 chest thrusts
Child > 1 yr
- head down or leaning forward
- 5 back blow
- 5 abdo thrusts
ineffective - paed BLS
Acute aspiration
inhalation of foreign material / gastric contents below the VCs
solid / liquid
chemical pneumonitis - mendelson syndrome
pneumonia - colonised orogastric contents
Risks in critical care
patient
- obesity
- severe GORD
- delayed gastric emptying - opioids
Iatrogenic
- supine position
- sedation / paralysis
bacterial colonisation - acid suppression, enteral feed, elderly
presenting - at time of intubation, witnessed, airway obstruction (blood, clot), VAP, lobar collapse
Aspiration Mx in critical care
A-E
manage choking
suction airway
recovery position if appripiate
decompress stomach
intubate
chest physio / bronchoscopy
supportive therapy - LPV, antimicrobials
Aspiration prevention
airway protection if indicated
RSI
Avoid GI stasis
Aspiration of NG before procedures
Avoid excessive sedation
Inhalation injury
Pathology associated with inhaling hot smoke, leading to mucosal damage in oral cavity and respiratory tract, lung parenchymal injury and absorption of toxic substances
Pathophysiology of inhalation injury
heat
- burns to airway and lower respiratory tract
- progressive oedema
particulate matter / irritants
- increased airway resistance and WOB
- inflammatory cascade
ROS
Asphyxiation
- low FiO2
- CO intoxication
- Hydrogen cyanide
Indications for intubation in inhalation injury
- airway threatened
- concerning features on examination
- humanitarian
- facilitation of imaging
Procedure - experienced operator, aim for first attempt, uncut ETT , low pressure cuff
difficulties in intubation following inhalation injury
- difficult preO2 - distress
- difficult FMV - loss of skin, oedema
- difficult laryngoscopy - oedema
- risk of hypoxaemia - hyper metabolic, V/Q mismatch, toxic compounds CO . cyanide
- c spine immobilisation
Respiratory support following inhalation injury
- LPV
- bronchoscopy, lavage
- nebulisers - saline, NAC
- chest physio
bronchial clearance
- important due to increased mucuc, inactivated surfactant, injury to mucociliary escalator
Nebilisers - salbutamol, NAC, heparin, saline
BAL - saline / bicarb
mechanical - postural, physiotherapy
Ludwigs angina
gangrenous cellulitis affecting soft tissues of neck and floor of mouth. profound sepsis and airway compromise
causes
- dental absces
- parapharyngeal abscess
- mandibular fracture
- oral laceration
predisposed - immunocompromised, poor oral hygiene, recent dental treatment
Concerning airway features
- generalised oedema, increased soft tissue, laryngeal oedema
- drooling or inability to swallow
- anterior distribution of infection - reducing effect of laryngoscopy
- trismus
- less mobile soft tissues
- front of neck access may be difficult due to infection
Mx Ludwigs angina
- ENT / FNE diagnosis
- dexamethasone, abx, adrenaline nebs
- Supprotive mx of infection
- airway protection - AFOI, awake tracheostomy
- source control - surgical debrimdenet
lemierres syndrome - necrobacillosis spreads to deep tissues, septic thrombophlebitis of IJV
massive haemoptysis
large volume haemorrhage originating within the respiratory tract
relevant to critical care as patients can rapidly deteriorate - haemorrhage shock, respiratory failure, airway obstruction
100ml in 1 episode, 1000ml / 24hr / volume threatening life
high mortality - asphyxiation more than exsanguination
Causes
- inonimate artery erosion
- arteriobronchial fistula
- PE / lung infarction
- AV malformation
- infection - TB, lung abscess, necrotising pneumonia, aspergilloma
I- inflammatory - GPA, bronchiectasis - lung cancer / metastases
- trauma
- iatrogenic - post bronchospy
Mx massive haemoptysis
- airway protection - if asphyxiation risk
- bronchoscopy, suction, lavage, topical adrenaline
- localise site of bleeding - bronchoscopy, CT
- definitive mx - IR, thoracotomy
- Supportive care - oxygenation, haemorrhage management, antibiotics
airway mx in massive haemoptysis
issues
- visual field obscured by blood
- haemodynamic instability
- ventilation issues due to volume of blood in airway
adaptations
- bleeding side down
- wide bore single lumen tube to facilitate bronchoscopy
- selected ventilation of contralateral lung - bronchoscope guided
- occlusive catheterisation of bleeding site
what are the most common tracheostomy emergencies
Loss of airway
- obstructed
- dislodged
Haemorrhage
- at time of insertion
- delayed e.g. trachea-innominate artery fistula
air leak
cuff leak
recognising tracheostomy emergency
airway
- obstructed
- unable to vocalise
- air leak
- snoring, stridor
breathing
- hypoxia, hypercapnia
- respiratory distress
- distress
- high pressures
- low Vt
specific
- visible displaement
- blood
- pain
general - anxiety, restlessness, agitation
tracheostomy related bleeding
early < 4 days
- skin / thyroid / anticoagulants
late
- erosion (innominate artery fistula)
- granuloma
- mucosal trauma
risks - low placement of tracheostomy, excessive movement, overinflation, suboptimal position
minor - dressing changes, topical coagulants, reviewing anticoagulants
major - sit up, ENT, anaesthetist, oxygen, hyperinflation of cuff or digital compression, theatre
preventing tracheostomy emergenceis
training - updates, simulation, appropriate environment
care - regular assessment, planned tracheostomy changes, secretion management, care of stoma site, equipment available, emergency airway responder available
communication - documentation, airway sign, accurate handover
Effects of laryngeal complications of airway management
prolonged intubation can lead to airway dysfunction
- failure of primary extubtion
- slow decannulation
- delayed recovery of speech, swallow, cough
complications include
- aspiration pneumonia
- dyspjahagia
- impaired airway protection
laryngeal complications following intubation or tracheostomy
- oedema
- arytenoid dislocation
- recurrent laryngeal nerve palsy
- vocal cord injury
- granuloma
- ulceration
- necrosis - submucosa (cuff pressure)
- stenosis
- laryngo/tracheomalacia
most vulnerable - arytenoid cartilages, vocal folds, subglottis
risk of laryngeal injury
patient
- age > 50
- high BMI
- diabetes, hypertension
- laryngopharyngeal reflux
- malnutrition
intubation
- cardiac, transplant, thyroid surgery
- emergency intubation
- skill level of operator
- bougie / stylet use
post intubation
- duration 6-10 days 5% risk
- agitation
- poor humidification
dysphonia
impaired voice quality - communication difficulties, low mood
post extubation dysphagia
occurs in 60% ICU patients requiring intubation
persistent in 1/3
contributed to by cognitive impairment, residual medications, sepsis
mechanical factors
- duration of intubation
- ETT size
- mucosal inflammation
- disuse muscle atrophy
- laryngeal injury
- laryngeal desensitisation
following tracheostomy
- tracheostomy results in absent / abnormal gas flow across larynx
- disuse atrophy
- uncoordinated glottic closure and swallow impairment
above cuff vocailiastion
retrograde gas flow above tracheostomy cuff and out of mouth via VCs - well positioned subglottic suction tracheostomy
Laryngeal complication management
- MDT
- prevention
- weaning and extubation / decannulation
- reduce risk factors
- secretion management
- oedema - steroids
- excessive salivation - hyoscine, glycolic
- altered gas flow - speaking valve
tracheal stenosis
narrowing of trachea (subglottic stenosis = airway narrowing below VCs)
translayryngeal intubation recognised cause - mucosal ischaemia, ulceration, fibrous scaring
SOB, inspiratory stridor, expiratory wheeze
dilatation / stenting / surgery
high volume low pressure cuffs aim to prevent
