As discussed in the Urgent Endotracheal Intubation (UEI) section, RSI is the default procedure employed due to its long history of established practice.
There are several less well established alternatives to RSI that have been proposed and utilised in various situations. The choice of technique will depend on a combination of factors including patient clinical characteristics, available resources and skill mix of airway team.
“Modified” RSI can mean different things to different people but seemingly the most common meaning is the addition of manual ventilations of the patient before and/or after the sedation and/or paralytic agent but prior to intubation. Most commonly this is performed after both the sedation/paralytic agent are delivered, during the apnoeic period before intubation. The reason this may be employed is that the patient is expected to not be able to tolerate the apnoeic period prior to intubation either due to :
– hypoxia from critical desaturation in a patient not optimally pre-oxygenated or even despite adequate pre-oxygenation due to their underlying lung pathology (eg severe pneumonia, pulmonary oedema). However additional techniques to optimise pre-oxgenation may avoid the need for modified RSI in some situations – see Problems Achieving Preoxygenation
– the rise in CO2 in the severely acidotic patient. In most patients the absence of ventilation during the apnoeic period and the resultant temporary rise in arterial CO2 is a non issue. However for a patient with severe acidosis the rise in CO2 during apnoea can result in a precipitous drop in pH and cardiac arrest.
A head injured patient may theoretically also benefit from modified RSI as either a fall in saturations or a rise in CO2 may have adverse consequences.
The ventilation during the apnoeic period can be provided through a face mask connected to bag ventilation or a ventilator. Gentle, slow, low pressure ventilation is less likely to cause gastric insufflation and some argue using the ventilator instead of the bag is likely to result in more controlled gentle ventilations – see this demonstration video.
Note some of the other UEI approaches below can offer alternative solutions in certain patient groups where modified RSI would be traditionally considered.
RSA is a technique pioneered by Darren Braude of Airway 911 and the Airway Corner of Emrap. The technique involves pushing your sedation and paralytic and then rapidly placing a supra-glottic airway (SGA) such as an LMA rather than waiting for optimal intubating conditions and attempting to intubate.
The technique was initially developed in the pre-hospital setting as it provided the quicker establishment of an advanced airway and minimised time at the scene, in an environment where intubation can be difficult, often requiring multiple attempts. Since then RSA has been increasingly promoted in the ED setting.
The RSA can be a stepping stone to an intubation providing the ability to safely ventilate the patient through the post sedation/paralytic apnoeic period before proceeding with intubation after optimal conditions are created. Intubation can proceed either by removing the SGA or through the SGA if an intubating LMA is used.
In between the placement of the SGA and intubation, the stomach can be drained by placement of a nasogastric tube. If this is planned, then the appropriate SGA that has a nasogastric port should be used (eg LMA Supreme).
ED scenarios that may benefit from RSA include:
– the patients outlined in Modified RSI section above who are either hypoxic or severely acidotic pre-intubation where the high risk post sedation/paralytic apnoeic period can be mitigated by rapid placement of a SGA and providing ventilations through it. Here RSA could be a safer alternative to modified RSI by theoretically reducing gastric insufflation and aspiration risk by ventilating via an SGA.
– the upper GI bleeder: this patient can be an intubation nightmare due to high aspiration risk and blood obscuring intubation view. RSA provides a significant degree of airway protection rapidly, allowing ventilation while a nasogastric tube is placed to drain the stomach. The patient can then be intubated in safer conditions with improved view and reduced aspiration risk.
Other RSA Resources:
DSI is procedural sedation for preoxygenation, using ketamine, in the patient who is non-compliant with preoxygenation due to altered mental state. DSI is described in our Problems Achieving Preoxygenation section.
In the ED this technique is considered for the patient with an anticipated difficult airway where intubation is required but not super-urgent. By intubating awake with the patient still spontaneously breathing we can avoid some of the potential complications of a failed intubation, however the technique is not without its own risks such as the risk of precipitating complete airway obstruction. It is unsuitable in patients with significant airway bleeding or significant airway secretions.
There’s even a free app for awake fibreoptic intubation!
Other Awake Intubation Resources:
Certain patients such as those with significant airway distortion in the laryngo-pharynx (eg mass/trauma/burns) may be most safely intubated via a planned surgical airway, which in the right patient could be performed awake.