Indications and Contraindications to Rapid Sequence Intubation and Induction

Rapid sequence intubation is an airway management technique that creates the optimal conditions the clinician needs for intubation. In other words, it’s a way to quickly sedate and paralyze a person in order to perform endotracheal intubation or other airway management strategies.

The ABC’s of RSI Indications

Airway protection

Airway protection, or the lack of airway protection, refers to those patients who are altered or at risk for aspiration. Examples include upper GI bleeds, large strokes, traumatic intracranial hemorrhages, etc. Aspiration events can lead to complications such as pneumonia or pneumonitis leading to respiratory failure which could be prevented with endotracheal intubation.

The patient who is obtunded or confused may be at risk for airway collapse. For example, the patient who is requiring frequent or continuous jaw thrust to maintain a patent airway should be intubated because of their risk of apnea from airway obstruction - the obtunded patient is discussed in more detail below - see the section on Consciousness.

Breathing

The failure to ventilate or oxygenate leading to hypercapnic or hypoxic respiratory failure is another indication for RSI (e.g. CHF exacerbation, COPD, or asthma exacerbation). In the emergent setting, evaluating a patient's ability to ventilate or oxygenate is made on clinical grounds. Look at the patient. Is their breathing labored and is there a concern that they will tire out from their breathing? If so, then consider early endotracheal intubation.

Adjuncts to your exam can also help determine a patient's ventilation and oxygenation status - pulse oximetry, continuous capnography, blood gases, etc. Temporary measures such as the delivery of oxygen through a nasal cannula, face mask, or even positive pressure ventilation can be used to stabilize the patient. Sometimes these interventions may prevent a patient's deterioration. But in general, patients who need assisted or positive pressure ventilation, in order to ventilate and oxygenate adequately, will likely require intubation, or at least it should be strongly considered.

Consciousness (Level of Consciousness)

A depressed level of consciousness is a risk for airway deterioration. Patients who are confused, lethargic, or unresponsive should prompt the clinician to assess for the patient’s ability to protect or maintain their airway. Regardless of the etiology, these patients may have difficulty protecting their airway, and placement of an endotracheal tube may be necessary to maintain a patent/open airway. Take, for example, a patient who presents for confusion secondary to a large stroke. This stroke could lead to neurological compromise and collapse of the airway. This patient would benefit from intubation in order to maintain airway patency.

There are different ways to assess airway protection. Historically, assessing a gag reflex was thought to be a reliable indicator of the patient’s ability to protect their airway. However, the gag reflex is absent in about 12-25% of normal adults. A better way to evaluate a person's ability to maintain and protect their airway is to evaluate the patient's level of consciousness and their ability to speak to you. Do they follow commands? Are they unconscious? Additionally, the clinician would want to observe the patient swallow and tolerate oral secretions. If the patient is unable to do this, then the patient is likely not maintaining a safe and patent airway.

In contrast to the confused/lethargic patient, also consider the combative and agitated patients and patients presenting with seizures. These patients are often difficult to assess because of the risk of injury they pose to care providers and themselves. Sedation, paralysis, and endotracheal intubation may be necessary to perform a physical exam and to allow the care providers to obtain necessary studies such as laboratory blood work, imaging, etc.

A patient who is seizing or in status epilepticus is a good example of a case that likely will need intubation. This allows the clinician to provide medications that sedate the patient and takes away their respiratory drive, but also are used to treat the seizure itself (e.g. high doses of benzodiazepines).

Disability

Traumatic injuries or exposures can lead to airway compromise such as in cases of traumatic brain injuries and burns. Burns to the airway or face can cause airway edema and swelling leading to rapid airway obstruction.

The classic example of traumatic cases requiring intubation is in those with a Glasgow Coma Scale less than 8 because of the risk of aspiration or loss of airway patency. Another example would be in cases of head trauma leading to increased intracranial pressure (ICP). Mechanical ventilation allows the clinician to target an appropriate PaCO2, (target PaCO2 35-40 mmHg), in an attempt to decrease ICP, but also provides airway protection as these patients are at high risk for aspiration.

Contraindications

Contraindications to RSI are few and relative. The anticipation of the difficult airway or impossible rescue oxygenation is a common contraindication. For example, in cases of facial trauma, the clinician should proceed with caution or consider alternative airway management strategies as there may be severe anatomical disruption leading to difficult or improperly placed endotracheal tubes. Alternatively, the clinician may consider an “awake” intubation approach in patients who might not tolerate apnea very well, because of profound hypoxemia or metabolic acidosis.

Summary

RSI is simply the steps a clinician takes to rapidly secure an airway involving the use of medications to sedate and paralyze the patient in order to try to create the most perfect conditions for intubation. Consider RSI in patients who fail to maintain or protect their airway, fail to ventilate or oxygenate, and in patients whose clinical course you expect to have a high likelihood of clinical deterioration.