Makindo Medical Notes.com

Patients do not die from a failure to intubate. They die from HYPOXIA due to failure to stop trying to intubate.

About

• Administration of a potent IV induction agent followed immediately by a rapidly acting neuromuscular blocking agent to induce unconsciousness and motor paralysis to facilitate tracheal intubation
• RSI is the standard technique for definitive emergency airway management in the emergency department to allow intubation while minimising the risk of pulmonary aspiration.

Difficult Airways

Induction Agents used

• Thiopentone: historically is the gold standard induction agent for RSI because of its rapid action and efficacy but can cause depressed cardiac and respiratory function
• Propofol: rapid onset of action and potent attenuation of pharyngeal, laryngeal, and tracheal reflexes. It also causes a considerable reduction in SVR and BP.
• Etomidate: is used increasingly for RSI of ED patients because of its rapid onset of anaesthesia, haemodynamic stability, cerebral protective properties, and lack of respiratory depression.

Paralysis with Induction

• Suxamethonium or another neuromuscular blocker may be used.
• Suxamethonium is the most commonly used neuromuscular blocking agent (NMB) for emergency rapid sequence intubation, having a rapid onset and short half-life.
• The dose in RSI is Suxamethonium 1.5 mg/kg.

Issues

• All induction agents have the potential to cause myocardial depression and secondary hypotension

Pre oxygenation

• This is the provision of high concentration oxygen to the patient for ideally 5 minutes prior to the procedure.
• This builds up a reservoir of oxygen in the lungs to allow a period of apnoea during RSI.
• If it is not possible to give 5 minutes of preoxygenation then 8 vital capacity breaths (the largest breaths a patient is able to take) should be taken.
• This allows the patient with normal lungs to maintain oxygen saturations over 90% for several minutes as shown in the table below:

Environment

• Clinical area e.g. resuscitation room
• Monitoring: ECG monitor, BP, SpO₂, capnography
• Intravenous access preferably two iv lines
• Position on trolley should optimise access for intubation
• Drugs:drawn up in labelled syringes + checked by medical staff

Equipment

• Two functioning laryngoscopes fitted with appropriate blade.
• Endo tracheal tube - test cuff inflation and have smaller sizes ready: Male, size 8 to 9 mm, Female, size 7 to 8 mm

Placement and proof

• Intubation should be performed carefully and gently. The larynx is visualised and the endotracheal tube placed. The stylet, if used, is then removed and the cuff inflated.
• Tube position is confirmed by a combination of: visualising the passage of the ET tube between the cords and listening to both sides of the chest and over the stomach.
• Assess end-tidal CO₂ measurement which is the most reliable method
• Cricoid pressure can be discontinued on instruction from the intubator. If intubation cannot be achieved, oxygenation will be maintained with basic airway manoeuvres and bag-mask ventilation.
• Further attempts at intubation can then be made safely.
• In failed intubation a return to basic airway management with bag-mask-valve ventilation using 100% oxygen will gain time until a definitive airway can be secured.

Post placement

• After tube placement is confirmed, the ET tube can be tied or taped in place. Blood pressure should be measured and reported to the team leader. Mechanical ventilation can now be initiated. A chest X-ray should be obtained to confirm ET tube position and assess the lungs.

Priorities in the failed airway situation

• Call for the most senior assistance available (Consultant in A&E, ICU, Anaesthetics, ENT +/- difficult airway trolley)
• Assess whether oxygenation is adequate:
• If able to oxygenate and maintain saturation >90% with BVM then may be able to buy sufficient time to use alternative techniques e.g. fibreoptic scope
• If unable to maintain saturation >90% then go back to GOOD basics while more help arrives/preparation for a surgical airway is occurring
• High flow oxygen via anaesthetic circuit or BVM
• Suction / OPA and NPA
• Head positioning +/- pillow
• 2 person ventilation technique
• Consider the use of an LMA

Failed Intubation

• As an assistant it is important to predict what the sequence of events will occur in the failed airway situation and what items of equipment may be required. Providing high concentration oxygen and going back to GOOD basic airway opening manoeuvres with the use of assistance and adjuncts will frequently allow some improvement in the patient condition. If good basic care improves matters and the oxygen saturation is greater than 90% then an expert may wish to try a further intubation attempt.
• The items of equipment and technique should be carefully considered, e.g. using a different laryngoscope blade, stylet or bougie, different size of ETT, rescue medication, altering amount of cricoid pressure, altering patient head position, considering the BURP (Backwards, Upwards, Rightwards Pressure on the larynx) manoeuvre etc.
• If the oxygen saturation still remains less than 90% despite optimum basic airway management it is likely that a surgical airway will be performed. This can be a needle or surgical cricothyroidotomy. It is vital to familiarise yourself with the equipment for this, where it is kept and how to be a good assistant when a surgical airway is performed.

Post Intubation Management

• After tube placement is confirmed, the ET tube can be tied or taped in place. Blood pressure should be measured and reported to the team leader.
• Mechanical ventilation can now be initiated. A chest X-ray should be obtained to confirm ET tube position and assess the lungs.

References

• Guidelines on RSI