# Rapid Sequence Induction

## Overview

This module describes how to intubate patients with a high risk of aspiration using rapid sequence induction (RSI). This technique protects the airway by minimising the time between induction and airway protection. The triad of RSI is pre-oxygenation, cricoid pressure, and fast acting drugs.

## Indications

1. Patients with a reduced level of consciousness (generally GCS 8 or less), requiring airway protection

2. Patients requiring urgent intubation such as in the emergency centre, or for emergency general anaesthesia

3. Elective intubation in patients with a risk factor for aspiration: pregnancy, known gastroesophageal reflux, history of bariatric surgery, recent opioid administration, severe pain, or conditions leading to delayed gastric emptying

## Contraindications

1. Complete airway obstruction

2. Severe facial injuries with loss of anatomical landmarks (consider front of neck access)

3. Known anaphylaxis or adverse reactions related to anaesthetic agents in use (consider alternative agents)

## Patient information & consent

When doing this procedure in an unresponsive patient, consent is generally implied. Patients with “Do Not Resuscitate” (DNR) orders, “Not For Max” orders, or living wills that specify that no resuscitation may be performed, may not be intubated. In elective patients, consent must be signed.

## Preparation

This procedure requires one, or preferably two assistants, and:

1. Oxygen, suction & a ventilator

2. Monitoring: blood pressure, ECG, sats, capnography

3. IV access (two large bore IVs in emergency intubations)

4. Non-sterile gloves

5. Laryngoscope (and backup) & 2 different sizes of laryngoscope blades (checked & working)

6. Endotracheal tubes
   Endotracheal tubes

   Size 7-7.5 for females and 7.5-8 for males

   (ETT)

7. Lubricant

8. 10 ml syringe

9. Bougie

10. Bag valve mask respirator (BVMR) and PEEP valve

11. A mask of the correct size

12. HEPA filter (attached to BVMR)

13. Oxygen tubing

14. Oropharyngeal airway devices

15. Supraglottic airway devices

16. Tape in strips for ETT securing

17. Choice of induction agents, paralytics, and opioids

18. Stethoscope

A difficult airway trolley should also be available with supraglottic devices.

## Site & Positioning

The patient should be in the “sniffing” position, with the ear aligned to the sternal notch. This may require building a ramp with pillows and blankets to raise the patient’s head.

## Procedure

Although RSI aims to avoid BVMR ventilation during preoxygenation and prior to the tube cuff being inflated, BVMR ventilation must be employed should hypoxia occur, even at the risk of aspiration. To minimise risk of gastric insufflation and resultant aspiration:

1. Maintain cricoid pressure
2. Insert oropharyngeal airway device
3. Keep BVMR pressures (adjusted on APL valve) at 10-15 cmH20 (the gastroesophageal valve opens at 20 cmH20) — colloquially referred to as ‘gentlation’.

Use medical asepsis with non-sterile gloves. Wear N95 masks as for aerosol-generating procedures.

1. Perform hand hygiene and don non-sterile gloves.

2. Assess the patient for a potential difficult airway and take cervical spine

   precautions
   precautions

   Where cervical spine injury is suspected, maintain C-spine protection with jaw-thrust during pre-oxygenation. During intubation, maintain manual inline stabilisation from the front.

   .

3. Attach monitoring, gain IV access and draw up your choice of drugs.

   * Be aware that ketamine comes in different concentration vials: 10, 50, and 100 mg/ml.

4. Prepare the ventilator if there is no impending emergency.

5. Preoxygenation options:

   1. If breathing spontaneously, normoxic: Pre-oxygenate for 3-5 mins 3-5 mins Or until ETO2 is at least 85%, with high flow (8-10 l/min) 100% oxygen using BMVR or anaesthesia circuit where available. Don’t squeeze the bag, and observe for chest rise.
   2. If hypoxic/apnoeic : Assist pre-oxygenation with gentle breaths ( gentlation ), and observe for chest rise.

6. Once you are ready to intubate, explain to the assistant what you expect from them.

7. Open and lubricate the endotracheal tube. Inflate and deflate the cuff to ensure patency. Preload bougie into ETT.

8. Check & connect suction, put ready for use under patients right shoulder.

9. Inject your choice of drugs, ask the assistant to initiate

   cricoid pressure
   cricoid pressure

   Evidence for cricoid pressure is poor, and it is often done incorrectly.
   General advice for RSI: apply cricoid pressure, but have a low threshold to remove it should there be difficulty in intubating. Cricoid pressure should be applied during induction, and maintained until the cuff is inflated.

   .

10. Await

    paralysis
    paralysis

    If suxamethonium was used, paralysis will be indicated by the fasciculation having stopped, or 30 seconds having passed.

    .

11. Ask the assistant to apply cricoid pressure with one hand, and to hold the ETT with the other, keeping the syringe nearby.

12. Insert the laryngoscope
    Insert the laryngoscope

    Hold the handle in your left hand. Insert the blade in the right side of the mouth and sweep the tongue across from right to left. Be gentle with teeth and lips. Push up and away from the patient, do not fulcrum with the blade. Gentle push the tip of the blade in the vallecula to visualise the vocal cords.

    .

13. Pass
    Pass

    Use your right hand. Insert to 10*patient's height in metres + 4; usually 19-22 cm.

    the endotracheal tube through the vocal cords, advancing the thick black line above the cuff to just past the vocal cords. The assistant should inflate the cuff with the 10 ml syringe, releasing cricoid pressure, removing the bougie and attaching the BVMR with HEPA filter.

14. Assess
    Assess

    Tracheal intubation confirmed by:
    1. Capnography — ETCO2 trace (gold standard)
    2. Bilateral breath sounds auscultated
    3. Equal chest rise
    4. Misting in the ETT

    tube placement.

15. Strap
    Strap

    the tube in place.

16. Attach the patient to the ventilator and plan for ongoing analgesia and sedation infusions.

17. Document procedure including indication for intubation, drugs used, number of attempts, time of intubation, size and depth of ETT, method of confirmation and any adverse events or difficulties.

18. Confirm tube placement with an X-ray if indicated.

## Troubleshooting

I can’t visualise the cords.

Always re-oxygenate the patient between attempts, providing breaths with the BVMR. Call for a senior. If not able to oxygenate, consider a supraglottic airway.

To optimise visualisation, position the patient with ear in line with sternal notch.

1. Check that your laryngoscope provides sufficient light
2. Check your viewing angle. Try straightening your back and bobbing your head up and down
3. Make sure that your laryngoscope is lifting the jaw, not acting as a lever
4. Ask your assistant to apply backwards, upwards, rightwards pressure to the cricoid cartilage
5. Reposition the blade, which may be too deep
6. Use a different size or shape of laryngoscope blade
7. Ask a more experienced colleague or senior to attempt intubation
8. Use a videolaryngoscope if available and you are familiar
9. Re-optimise the patient if unstable or induction/paralytic effects are wearing off

I can’t oxygenate the patient with BVMR breaths.

1. Call for help
2. Reposition the patient using basic head-tilt chin-lift or jaw thrust
3. Ensure an NPA or OPA is in situ when using BVMR
4. Use two handed mask seal
5. Increase PEEP
6. Rule out pneumothorax
7. Insert an LMA if not successful with mask ventilation

I can’t oxygenate the patient, and intubation or difficult airway devices have failed or are unavailable.

This is a can't intubate- can't oxygenate scenario, and front of neck access may be indicated.

I’m not sure how to draw up ketamine.

Ketamine is available in different concentrations; 10, 50, and 100 mg/ml. It is easiest to work with a 10 mg/ml solution, which comes as a 20 ml vial and can be used undiluted. If you have a 50 mg/ml vial (comes in a 10 ml vial), draw up 2 ml in a 10 ml syringe and add 8 ml of normal saline, making a 10 mg/ml solution.

For the 100 mg/ml solution (comes in a 10 ml vial), draw up 1 ml ketamine and add 9 ml normal saline in a 10 ml syringe, making a 10 mg/ml solution. For a 70 kg patient, you may need to draw up two 10 ml syringes, or one 20 ml syringe with 2 ml of ketamine.

Diluting high concentrations of ketamine is safe practice and avoids accidental misdosing.

## Risks

1. Anaesthetic drug reactions

2. Hypoxic brain injury

3. Cardiac arrest ± death due to hypoxia

4. Damage to dentition

5. Airway injuries

6. Aspiration & resultant pneumonia

## References

1. Schrader M, Urits I. Tracheal Rapid Sequence Intubation. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560592/

2. Sinclair RC, Luxton MC. Rapid sequence induction. Continuing Education in Anaesthesia Critical Care & Pain. 2005(5);2:p 45–48. Available from:https://doi.org/10.1093/bjaceaccp/mki016