Rapid Sequence Intubation (RSI) – Mnemonic Approach

Approach the patient with 9 Ps.

0-10 minutes (Possibility of Success): Anticipating difficult airway

Mnemonic: LEMON approach

1. Look externally: Remember “BONES

  • Beard
  • Obesity
  • No teeth
  • Elderly
  • Sleep apnea/Snoring

2. Evaluate 3-3-2 rule: Ideal dimensions for visualization of larynx

3-3-2 rule
  • 3 fingers in mouth: adequate mouth opening
  • 3 fingers under the chin (mentum to hyoid bone): mandible large enough to accomodate tongue
  • 2 fingers at top of neck (hyoid bone to thyroid cartilage): adequate neck length and laryngeal position

3. Mallampati: Predict ability of patient’s mouth to accomodate both laryngoscope and ET tube – class III and IV indicate limited oral access

mallampati grade
  • Class I: faucial pillars, soft palate, and uvula visualized
  • Class II: faucial pillars and soft palate visualized, but the uvula is masked by the base of the tongue
  • Class III: only the base of the uvula can be visualized.
  • Class IV: none of the three structures can be visulaized

4. Obstruction of upper airway: Infections, tumors, foreign body, etc.

5. Neck mobility

0-10 minutes: Preparation

Mnemonic: SOAP ME

1. Suction

2. Oxygen (mask and BVM ventilation)

3. Airway equipment:

  • Laryngoscopes: Atleast 2 functioning handles and various sized blades
  • ET tube: Chosen size and one size smaller ETT must be available and ET cuff must be tested
    • Adult male: 7.5-8
    • Adult female: 7-7.5
    • Children: 4 + (age in years/4)

4. Pharmacy:

  • Patent IV line
  • Specific RSI medications: Proper dosing, Sequence of administration, Agents drawn up and labelled

5. Monitoring Equipment: Blood pressure and Pulse oximetry (ETCO2 if available)

0-5 minutes: Preoxygenation

  • Nitrogen washout” with 100% oxygen for 5 minutes – replace room air (80% nitrogen + 20% oxygen) with 100% oxygen in lungs to create oxygen reservoir

0-3 minutes: Pretreatment

Mnemonic: LOAD

  1. Lidocaine
  2. Opioid (fentanyl)
  3. Atropine
  4. Defasciculation (Pancuronium, Vecuronium)

Zero minutes: Paralysis

1. Induction:

  • Choice: Etomidate
  • Hypotensive, Hypovolemic and Bronchospastic patients: Ketamine
  • Others: Thiopental, Methohexital, Midazolam, Propofol

2. NM Blockade:

a. Depolarizing agent:

  • Succinylcholine: Onset: 45-60 seconds; Duration: 6-12 minutes

b. Non-depolarizing agent:

  • Rocuronium: Onset: 50-70 seconds; Duration: 30-60 minutes
  • Vecuronium: Onset: 90-120 seconds; Duration: 60-75 minutes
  • Pancuronium: Onset: 100-150 seconds; Duration: 120-150 minutes

For the dosage and brief pharmacology: https://med.umkc.edu/docs/em/Intubation_Chart.pdf

0 + 20-30 seconds: Protection and Positioning

Sellick’s maneuver (Cricoid pressure) by assistant:

  • Start: After patient begins to lose consciousness (prevent patient discomfort and vomiting)
  • Application: 10lbs pressure to cricoid to compress esophagus and prevent regurgitation of gastric contents
  • End: After ETT is placed, position verified and cuff inflated


  • Sniffing position: Flexion of neck on body and Extension of head on neck to align 3 axes (oral, phayngeal and laryngeal)
  • C-spine injury suspected: Use neutral position

0 + 45 seconds: Placement

a. Laryngoscope

  1. Confirm complete paralysis: check for flaccidity of mandible
  2. Open mouth with right hand
  3. Hold larygoscope in left hand
  4. Insert laryngoscope into the right side of the patient
  5. Tongue is displaced to the left
  6. Curved (Macintosh) blade is slid into valeculla; Straight (Miller) blade is positioned below epiglottis
  7. Laryngoscope handle is advanced along the axis of the blade at an angle of 45° to the patient’s body.
  8. If laryngeal apparatus not vissible: Apply “BURP” maneuver – Backward, Upward and Right Pressure on thyroid cartilage

b. ET tube

  1. Insert ETT tube with right hand until cuff is 2-3 cm below vocal cords (23 cm marker on corner of mouth in adult male and 21 cm in adult female)
  2. Remove stylet
  3. Inflate cuff

0 + 45 seconds: Proof of correct ETT placement

a. Clinical:

  • Laryngoscopist observing ETT pass through vocal cords
  • Clear and equal breath sounds over both lung fields
  • Absence of breath sounds over epigastrium
  • Symmetrical chest rise during ventilation
  • Fogging of ETT during ventilation

b. Pulse oximetry (not a primary indicator): drop in SpO2 may indicate esophageal intubation

c. ETCO2 detection:

  • “Normal square waveforms” will not be detectable in capnograph if esophageal intubation has occured
  • Color change from purple to yellow will be absent in colorimetric ETCO2 detector if esophageal intubation has occured

d. Suction apparatus:

  • ET tube in esophagus (collapsible): resistance with attempt to suction
  • ET tube in trachea (non-collapsible due to cartilage rigns): free flow of air with attempt to suction

0 + 1 minute: Post-intubation management

cxr et tube
  1. Secure tube in place
  2. Monitor vitals frequently
    • Bradycardia may suggest hypoxia due to esophageal intubation
    • Hypertension suggests inadequate sedation
    • Hypotension may suggest tension pneumothorax, decreased venous return, cardiac cause or induction agent
  3. Configure mechanical ventilator
  4. CXR to assess ET tube position and condition of patient’s lungs (proper tube depth is 2-3 cm above carina)
  5. Long-term sedation and paralysis:
    • Diazepam 0.2 mg/kg or Lorazepam 0.05-0.1 mg/kg (may be repeated for any signs of awareness)
    • Pancuronium 0.1 mg/kg or Vecuronium 0.1 mg/kg (1/3rd of intial dose may be repeated after 45-60 minutes if motor activity is detected)

LIVES Mnemonic for Tracheal Intubation

L Laryngoscope Left-handed laryngoscopy 
I Intubation tube Intubation and insufflation of the cuff using a syringe 
V Ventilatory device Ventilation 
E End-tidal CO2 monitor Evaluation of tube position with monitor and by auscultation 
S SaO2 monitor Secure with tie and monitor oxygen saturations 

Watch the whole thing


  1. An Introduction to Clinical Emergency Medicine by S.V. Mahadevan and Gus M. Garmel
  2. BJA: British Journal of Anaesthesia, Volume 118, Issue 2, February 2017, Pages 270–271, https://doi.org/10.1093/bja/aew459

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