The Urgent Endotracheal Intubation (UEI) describes the primary intubation scenario that occurs in the ED, where intubation must proceed in a semi-rapid or rapid fashion due to the patient’s clinical state. It is usually performed for airway protection/maintanence, to provide ventilatory support or as part of the management package of the critically unwell patient.
The most common and well established procedure used for UEI in the ED is Rapid Sequence Intubation (RSI) and as such remains the default procedure of choice.
ED patients either may not be fasted or due to illness have delayed gastric emptying so are effectively unfasted. Therefore it is safest to treat the patients as if they have a potential full stomach and at resultant increased risk of aspiration. Consequently RSI is primarily designed to minimise the risk of aspiration and rapidly obtain a secure airway by:
1. Minimising the need for manual ventilations. This reduces gastric insufflation and resultant aspiration risk and is achieved by:
– creating optimal intubating conditions to maximise “first past” intubation success (i.e success on 1st attempt). Multiple intubation attempts increase aspiration risk (as manual ventilations must be provided between attempts) and correlate with higher mortality rates.
– avoiding ventilations prior to 1st intubation attempt (see below)
2. Minimising the period of time required to secure the airway. This minimises the period of time that the patient is sedated (with attendant loss of airway protective reflexes) and without a secure airway thus reducing the risk aspiration. In addition this provides benefit in the rapidly deteriorating patient, in that an airway is secured rapidly before they lose their patent airway.
The key distinctive technical aspects of RSI:
– the use of predetermined bolus doses of sedation agents and muscle relaxants prior to the intubation delivered virtually simultaneously. This creates optimal intubating conditions in a rapid fashion (eg 45 seconds) to facilitate first past success. This technique is as opposed to the titration of sedation agent that can occur in elective intubations with the later addition of a paralytic.
– the avoidance of any manual ventilations of the patient before the first attempt at intubation. This is as opposed to the practice that often occurs in elective intubations where the fasted patient can be safely manually ventilated before and/or after the paralytic agent is administered and prior to attempting intubation.
The various considerations, equipment, drugs and procedures involved in RSI are detailed and manifold so will be discussed in future Bite-Sized Basics. However of note, most aspects of RSI (eg preoxygenation) are simply standard parts of any elective intubation- it is the avoidance of manual ventilation and the simultaneous bolus administration of sedation and paralytic agents that defines RSI.
Of note RSI should be used with caution in the patient in whom difficult ventilation or intubation is anticipated due to the risk of the can’t intubate, can’t oxygenation/ventilate scenario occurring.
Historically Cricoid Pressure was considered a standard part of RSI but it’s use should be considered optional and many Emergency Physicians have abandoned it entirely due to significant evidence of harm without any proven benefit. See LITFL for more on Cricoid Pressure.