EM Notes – Intubation

Indications

  1. Loss of airway protection
    1. Loss of reflexes, e.g. obtunded /↓GCS (<8), muscle relaxed (e.g. for hyperthermia)
      1. Risk of aspiration from GIT, blood or secretions
  2. Loss of airway patency
    1. Potential for obstruction: e.g. burns, epiglottitis
  3. Prophylactically
    1. Likely to lose airway protection/patency: e.g. neck haematoma, airway burns
    2. Control of airway: e.g. pre-transfer, unco-op patient needing urgent scan/Rx
  4. Inadequate ventilation
    1. Treatment of hypercapnea: e.g. HI, TCA OD, severe COPD
    2. Selective lung ventilation e.g. massive haemoptysis, bronchopulmonary fistula
  5. Inadequate oxygenation
    1. E.g. Severe APO, ARDS, PE, CN or CO toxicity
  6. Other:
    1. Drug delivery – rare except for neonates & surfactant

Contraindications

  1. Absolute
    1. Total upper airway obstruction: a surgical airway is required
    2. Total loss of facial/oropharyngeal landmarks: a surgical airway is required
  2. Relative
    1. Anticipated “difficult” airway, in which intubation may be unsuccessful and result in ‘can’t intubate, can’t ventilate’ situation – esp if drugs given.
      1. If currently able to ventilate with bag & mask, continue and:
      2. Get help
      3. Consider difficult airway adjuncts/algorithm or rarely awake intubation.

Rapid Sequence Induction/Intubation (RSI)

  1. Preferred method of endotracheal intubation in ED
  2. Results in rapid unconsciousness (induction) and muscle relaxation (paralysis)
  3. Aim is to intubate the trachea with minimal/no use bag-valve-mask (BVM) ventilation, which can cause gastric insufflation
  4. Important as most patients not fasted and at greater risk for vomiting and aspiration
  5. Other risk factors for gastric aspiration are:
    1. intra-abdominal pathology – gastric paresis (drugs, pain, diabetes, uraemia),
    2. intestinal obstruction, inflammation, peptic ulcer disease
    3. oesophageal disease – symptomatic reflux, motility disorders
    4. pregnancy
    5. obesity
  6. RSI is not indicated/required in an unconscious, apnoeic or arrested patient; intubation proceeds without pre-treatment, induction, or paralysis.
  7. 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

  1. MOANS – diff vent – Mask (beard, trauma), Age>55, Obese, No teeth, Stiff (COAD, preg)
  2. LEMON **- for a difficult laryngoscopic view
    1. Look externally for any obvious impairment
      1. Obese, congenital/acquired deformity
    2. Evaluate 3-3-2 rule with patient fingers
      1. Mouth opening (1), Mento-hyoid distance (2) &
        Hyoid-thyroid cartilage distance (3)
    3. Mallampati – tongue/mouth size
      1. I – Pillars/palate/uvula fully visible
      2. II – Uvula partially visible
      3. III – Only base of uvula visible
      4. IV – None of 3 visible
    4. Obstruction (OSA, epiglottis, mass)
    5. Neck mobility (RA, C-spine collar)
  3. RODS – diff LMA: Restricted mouth opening, Obstructed/obese, Distorted anat, Stiff

Preparation: SOAPME

  1. Suction
  2. O2 & mask
  3. Airway equip – check laryngoscopes (Macintosh/Miller), ETTs, stylet, bougie, LMA, cric kit
    1. ETT size – Neonate: 3.5. Child: age/4+4 (uncuffed) or +3.5 (cuffed). Adult: 7.5-8
    2. ETT length@lips – Child: age/2+12, Adult: 20-23cm
  4. Personnel – at least airway nurse, drug doctor, intubator
  5. Medications – drugs and IV line checked
  6. Equipment – Pulse oximeter, BP, HR, ETCO2

Plan A & Plan Bs

  1. Decide on plan of choice, but also backup plan, difficult airway plan_

Pre-oxygenate

  1. 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

  1. LOAD controversial – not routinely used in RSI
  2. Lignocaine 1.5mg/kg – ?↓ICP peak, consider if ↑↑ICP, bronchospasm
  3. Opioid – fentanyl 3mcg/kg – if need to blunt symp. resp. e.g. dissection, IHD, ↑ICP
  4. Atropine 20mcg/kg (min 0.1mg, max 1mg) – if bradycardia in young child or from sux
  5. Defasciculating dose of NMB (eg vecuronium 0.01mg/kg) – rarely used to ↓SE of sux

Positioning:

  1. EAM-to-sternal notch position except infants or ?C-Spine injury. Jaw thrust.

Pressure on cricoid (Sellick)

  1. Evidence against it. However BURP (Backward, Up, Rightward Pressure) may improve view

Pharmacy:

  1. induction then paralysis. Std adult dose in [], _use ½-¼ induction dose if elderly/↓BP
  2. 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)
  3. IV
    1. suxamethonium 1-2mg/kg [100mg] (CI:{burns/crush/denervation/CVA/abdo sepsis}>5d, malig hyperT, neuromusc dz,↑K+), OR
      1. rocuronium 1mg/kg [50mg] OR
      2. vecuronium 0.1mg/kg [5mg]

Place ETT, secure it & prove placement

  1. Direct vision through cords
  2. Listen @ axillae/epigastrium
  3. Equal chest rise
  4. Sustained ETCO2
  5. Fogging of tube
  6. CXR

Post-tube sedation ± paralysis

  1. IV morphine 10-40mcg/kg/hr + midazolam 2-6mcg/kg/min OR propofol 1-4mg/kg/hr
  2. IV rocuronium OR vecuronium 0.1mg/kg q30-45min (Immed rev: sugammadex 16mg/kg)

Difficult / Failed Intubation Algorithm

Complications of Intubation

Laryngoscopy

  1. Mechanical
    1. Damage to teeth, lips, gums or other soft tissues
    2. Coughing, laryngospasm, bronchospasm, vomiting ± aspiration
    3. Hyperextension cervical injury
    4. TMJ dislocation
  2. Laryngoscopy Physiological
    1. Cardiovascular responses – HT, tachy, arrhythmias, bradys in children, ischaemia
    2. Respiratory responses – coughing, laryngospasm, bronchospasm
    3. ↑ICP – ↑CBF proportional to CMRO2, raised MAP, ↓venous drainage with coughing
    4. Hypoxaemia / hypercarbia – difficult or prolonged attempts

Tracheal Intubation

  1. Failed intubation
  2. Misplaced intubation – oesophageal, endobronchial intubation
  3. Obstruction – kinking, cuff overinflation/herniation, blood, mucus, FB
  4. Mechanical damage – pharynx, larynx, cords, trachea, oesoph – dissection, perforation

Nasal Intubation

  1. Failure to pass a tube
    1. Haemorrhage – coagulopathy, pregnancy, polyps, adenoids, other local pathology
    2. Bacteraemia – CNS spread of infection, endocarditis risk
  2. Membrane necrosis / ulceration
  3. Sinusitis ± otitis (usually long-term intubation)
  4. Basilar skull perforation – usually base of skull #

Laryngeal Mask Airway

Indications

  1. Spontaneous ventilation anaesthesia – convenience or if airway difficult by other means
    1. As an aid to intubation – through LMA (40% success) or with bougie (80% success)
    2. Intubating LM (ILM) can use up to size 8.0 ETT
    3. In failed intubation – Can’t intubate, can’t ventilate or anaesthesia must proceed

Disadvantages

  1. Does not protect the airway
  2. May result in pharyngeal discomfort or trauma
  3. Obstruction of the upper airway
  4. Limited use for IPPV – described, but risks of gastric aspiration – not recommended

Extubation

Criteria for Extubation

General

  1. Ability to protect the airway
  2. Adequate spontaneous ventilation
  3. Adequate oxygenation
  4. Ability to clear secretions

Specific

  1. FIO2 < 50%
  2. PEEP < 5 cmH2O
  3. PaO2 > 60 mmHg
  4. PaCO2 < 50 mmHg
  5. IMV < 4 bpm
  6. Spont RR < 30 bpm
  7. VC > 30 ml/kg
  8. A resolving CXR
  9. No other major organ failure

Extubation Procedure

  1. Check equipment – suction & ability to re-intubate
  2. Place Guedel/bite block
  3. Ensure sedation/muscle relaxation has worn off or reversed
  4. Suction NG tube, oropharynx
  5. Untape tube
  6. Remove air from cuff
  7. Remove ETT on expiration
  8. Re-suction oropharynx & apply oxygen by face mask
  9. Turn patient into recovery position and re-assess ventilation

Complications of Extubation

  1. Failure – hypoxaemia / hypercarbia, exhaustion
  2. Respiratory responses – coughing, laryngospasm, bronchospasm, vomiting ± aspiration
  3. cardiovascular responses – HT, arrhythmias (brady in children), myocardial ischaemia
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