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