Indications
- Loss of airway protection
- Loss of reflexes, e.g. obtunded /↓GCS (<8), muscle relaxed (e.g. for hyperthermia)
- Risk of aspiration from GIT, blood or secretions
- Loss of reflexes, e.g. obtunded /↓GCS (<8), muscle relaxed (e.g. for hyperthermia)
- Loss of airway patency
- Potential for obstruction: e.g. burns, epiglottitis
- Prophylactically
- Likely to lose airway protection/patency: e.g. neck haematoma, airway burns
- Control of airway: e.g. pre-transfer, unco-op patient needing urgent scan/Rx
- Inadequate ventilation
- Treatment of hypercapnea: e.g. HI, TCA OD, severe COPD
- Selective lung ventilation e.g. massive haemoptysis, bronchopulmonary fistula
- Inadequate oxygenation
- E.g. Severe APO, ARDS, PE, CN or CO toxicity
- Other:
- Drug delivery – rare except for neonates & surfactant
Contraindications
- Absolute
- Total upper airway obstruction: a surgical airway is required
- Total loss of facial/oropharyngeal landmarks: a surgical airway is required
- Relative
- Anticipated “difficult” airway, in which intubation may be unsuccessful and result in ‘can’t intubate, can’t ventilate’ situation – esp if drugs given.
- If currently able to ventilate with bag & mask, continue and:
- Get help
- Consider difficult airway adjuncts/algorithm or rarely awake intubation.
- Anticipated “difficult” airway, in which intubation may be unsuccessful and result in ‘can’t intubate, can’t ventilate’ situation – esp if drugs given.
Rapid Sequence Induction/Intubation (RSI)
- Preferred method of endotracheal intubation in ED
- Results in rapid unconsciousness (induction) and muscle relaxation (paralysis)
- Aim is to intubate the trachea with minimal/no use bag-valve-mask (BVM) ventilation, which can cause gastric insufflation
- Important as most patients not fasted and at greater risk for vomiting and aspiration
- Other risk factors for gastric aspiration are:
- intra-abdominal pathology – gastric paresis (drugs, pain, diabetes, uraemia),
- intestinal obstruction, inflammation, peptic ulcer disease
- oesophageal disease – symptomatic reflux, motility disorders
- pregnancy
- obesity
- RSI is not indicated/required in an unconscious, apnoeic or arrested patient; intubation proceeds without pre-treatment, induction, or paralysis.
- RSI should be used with caution in a patient with a suspected difficult airway to prevent ‘can’t intubate, can’t ventilate’ situation following sedating & paralysing the patient.
The 10 P’s of Intubation:
Predict difficulty
- MOANS – diff vent – Mask (beard, trauma), Age>55, Obese, No teeth, Stiff (COAD, preg)
- LEMON **- for a difficult laryngoscopic view
- Look externally for any obvious impairment
- Obese, congenital/acquired deformity
- Evaluate 3-3-2 rule with patient fingers
- Mouth opening (1), Mento-hyoid distance (2) &
Hyoid-thyroid cartilage distance (3)
- Mouth opening (1), Mento-hyoid distance (2) &
- Mallampati – tongue/mouth size
- I – Pillars/palate/uvula fully visible
- II – Uvula partially visible
- III – Only base of uvula visible
- IV – None of 3 visible
- Obstruction (OSA, epiglottis, mass)
- Neck mobility (RA, C-spine collar)
- Look externally for any obvious impairment
- RODS – diff LMA: Restricted mouth opening, Obstructed/obese, Distorted anat, Stiff
Preparation: SOAPME
- Suction
- O2 & mask
- Airway equip – check laryngoscopes (Macintosh/Miller), ETTs, stylet, bougie, LMA, cric kit
- ETT size – Neonate: 3.5. Child: age/4+4 (uncuffed) or +3.5 (cuffed). Adult: 7.5-8
- ETT length@lips – Child: age/2+12, Adult: 20-23cm
- Personnel – at least airway nurse, drug doctor, intubator
- Medications – drugs and IV line checked
- Equipment – Pulse oximeter, BP, HR, ETCO2
Plan A & Plan Bs
- Decide on plan of choice, but also backup plan, difficult airway plan_
Pre-oxygenate
- 3min or 8 full breaths _@ _≥15L O2 _NRB. Pos 20% head up. If SaO2<95%: PEEP 5-15cmH20. After drugs: NP O2 @ 15L/min & _if SaO2<95% cont BVM±PEEP @ 6 breaths/min.
Pre-treatment 3 mins before intubation
- LOAD – controversial – not routinely used in RSI
- Lignocaine 1.5mg/kg – ?↓ICP peak, consider if ↑↑ICP, bronchospasm
- Opioid – fentanyl 3mcg/kg – if need to blunt symp. resp. e.g. dissection, IHD, ↑ICP
- Atropine 20mcg/kg (min 0.1mg, max 1mg) – if bradycardia in young child or from sux
- Defasciculating dose of NMB (eg vecuronium 0.01mg/kg) – rarely used to ↓SE of sux
Positioning:
- EAM-to-sternal notch position except infants or ?C-Spine injury. Jaw thrust.
Pressure on cricoid (Sellick)
- Evidence against it. However BURP (Backward, Up, Rightward Pressure) may improve view
Pharmacy:
- induction then paralysis. Std adult dose in [], _use ½-¼ induction dose if elderly/↓BP
- IV (midazolam 0.1-0.3mg/kg [5-10mg] ± fentanyl 1-5mcg/kg [100mcg]) OR thiopentone 3-5mg/kg [200mg], ketamine (asthma, ↓BP, not IHD,↑BP) 1-2mg/kg [100mg] OR propofol [100mg] 0.5-1.5mg/kg (not ↓↓BP)
- IV
- suxamethonium 1-2mg/kg [100mg] (CI:{burns/crush/denervation/CVA/abdo sepsis}>5d, malig hyperT, neuromusc dz,↑K+), OR
- rocuronium 1mg/kg [50mg] OR
- vecuronium 0.1mg/kg [5mg]
- suxamethonium 1-2mg/kg [100mg] (CI:{burns/crush/denervation/CVA/abdo sepsis}>5d, malig hyperT, neuromusc dz,↑K+), OR
Place ETT, secure it & prove placement
- Direct vision through cords
- Listen @ axillae/epigastrium
- Equal chest rise
- Sustained ETCO2
- Fogging of tube
- CXR
Post-tube sedation ± paralysis
- IV morphine 10-40mcg/kg/hr + midazolam 2-6mcg/kg/min OR propofol 1-4mg/kg/hr
- IV rocuronium OR vecuronium 0.1mg/kg q30-45min (Immed rev: sugammadex 16mg/kg)
Difficult / Failed Intubation Algorithm
Complications of Intubation
Laryngoscopy
- Mechanical
- Damage to teeth, lips, gums or other soft tissues
- Coughing, laryngospasm, bronchospasm, vomiting ± aspiration
- Hyperextension cervical injury
- TMJ dislocation
- Laryngoscopy Physiological
- Cardiovascular responses – HT, tachy, arrhythmias, bradys in children, ischaemia
- Respiratory responses – coughing, laryngospasm, bronchospasm
- ↑ICP – ↑CBF proportional to CMRO2, raised MAP, ↓venous drainage with coughing
- Hypoxaemia / hypercarbia – difficult or prolonged attempts
Tracheal Intubation
- Failed intubation
- Misplaced intubation – oesophageal, endobronchial intubation
- Obstruction – kinking, cuff overinflation/herniation, blood, mucus, FB
- Mechanical damage – pharynx, larynx, cords, trachea, oesoph – dissection, perforation
Nasal Intubation
- Failure to pass a tube
- Haemorrhage – coagulopathy, pregnancy, polyps, adenoids, other local pathology
- Bacteraemia – CNS spread of infection, endocarditis risk
- Membrane necrosis / ulceration
- Sinusitis ± otitis (usually long-term intubation)
- Basilar skull perforation – usually base of skull #
Laryngeal Mask Airway
Indications
- Spontaneous ventilation anaesthesia – convenience or if airway difficult by other means
- As an aid to intubation – through LMA (40% success) or with bougie (80% success)
- Intubating LM (ILM) can use up to size 8.0 ETT
- In failed intubation – Can’t intubate, can’t ventilate or anaesthesia must proceed
Disadvantages
- Does not protect the airway
- May result in pharyngeal discomfort or trauma
- Obstruction of the upper airway
- Limited use for IPPV – described, but risks of gastric aspiration – not recommended
Extubation
Criteria for Extubation
General
- Ability to protect the airway
- Adequate spontaneous ventilation
- Adequate oxygenation
- Ability to clear secretions
Specific
- FIO2 < 50%
- PEEP < 5 cmH2O
- PaO2 > 60 mmHg
- PaCO2 < 50 mmHg
- IMV < 4 bpm
- Spont RR < 30 bpm
- VC > 30 ml/kg
- A resolving CXR
- No other major organ failure
Extubation Procedure
- Check equipment – suction & ability to re-intubate
- Place Guedel/bite block
- Ensure sedation/muscle relaxation has worn off or reversed
- Suction NG tube, oropharynx
- Untape tube
- Remove air from cuff
- Remove ETT on expiration
- Re-suction oropharynx & apply oxygen by face mask
- Turn patient into recovery position and re-assess ventilation
Complications of Extubation
- Failure – hypoxaemia / hypercarbia, exhaustion
- Respiratory responses – coughing, laryngospasm, bronchospasm, vomiting ± aspiration
- cardiovascular responses – HT, arrhythmias (brady in children), myocardial ischaemia