Defining Moderate Sedation and a Framework for Identifying the Sedation State of a Patient

Moderate sedation and analgesia are administered to patients undergoing brief medical procedures to ensure they are comfortable and their pain is managed. Procedures that require moderate sedation are common in a variety of medical areas, including gastroenterology, emergency medicine, cardiology, dental, and oral surgery specialties. Millions of these outpatient surgeries are performed in the United States each year. While moderate sedation is considered an anesthesia technique, non-anesthesia care providers (registered nurses, non-anesthesiologist physicians, dentists, oral surgeons, etc.) with proper training may be responsible for the administration of the sedatives and analgesics.

Moderate sedation is not without risk for the patient. Sedation medications and analgesics dosed inappropriately may lead to sedation-related adverse effects, such as respiratory depression, hypoxia, airway obstruction, and hypotension. One of the first key steps in providing moderate sedation safely is understanding exactly what is expected of the patient in terms of their physical responses and vital signs.

One part of safely administering sedation is to ensure the level of sedation is truly assessed as moderate for the patient. The reality is that this may be more difficult to discern and there may be gray areas to interpret.

In this article, we will discuss moderate sedation in the context of the sedation continuum’s levels of sedation.

Definition of Moderate Sedation

Moderate sedation is defined in the American Society of Anesthesiologists’ Practice Guidelines for Moderate Procedural Sedation and Analgesia as:
A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway when spontaneous ventilation is adequate. Cardiovascular function is usually maintained.

Moderate procedural sedation and analgesia, or moderate sedation for short, is also known informally as conscious sedation or twilight sleep.

Let’s take a look at moderate sedation in the context of the sedation continuum.

Levels of Sedation

The levels of sedation lie within a continuum that progresses from “no sedation” to “general anesthesia” as the sedation level increases. In addition to the “no sedation” state, there are four sedation states that exist within the sedation continuum, including moderate sedation.

Table 1 identifies the sedation states, as well as a number of patient characteristics that a sedation practitioner would monitor or evaluate to differentiate between each of the states. “Responsiveness” is how the patient might respond to verbal or tactile stimulation. “Airway” is the consideration of the patency of the patient’s airway (i.e., whether the patient’s airway is intact). “Spontaneous ventilation” is how well the patient is breathing without intervention.

“Cardiovascular function” is the consideration of the patient’s heart rate, blood pressure, rhythm, and other indicators of the patient’s heart function.

Table 1: The four key sedation states of the sedation continuum.

Let’s look at each of these states in detail.

Minimal Sedation

A typical goal of minimal sedation is to reduce the level of anxiety for the patient with very little to no change in the patient’s level of sedation. As an example, a single medication might be administered orally to achieve a minimal sedation state. The patient’s anxiety level is diminished, they are able to recall the episodes of the procedure, and their protective reflexes remain unaffected. The patient is completely responsive to verbal inquiry, and the airway, spontaneous ventilation, and cardiovascular function are all unaffected.

Moderate Sedation

We have already provided a formal definition of the moderate sedation state above, and it is clear that moderate sedation is considerably different from the minimal sedation state. A moderately sedated patient has a drug-induced depression of consciousness in the absence of a verbal or tactile stimulus. However, the patient’s airway is maintained without any intervention. Spontaneous ventilation is present and adequate. Cardiovascular function is not significantly altered. The patient will respond appropriately to verbal or light tactile stimulation.

Deep Sedation

With deep sedation, a patient may not respond to verbal or light tactile stimulus. Instead, they may only respond to repeated and loud verbal commands or painful stimulation. A deeply sedated patient may need intervention to maintain the airway to prevent airway obstruction. Spontaneous ventilation may be diminished or absent. Cardiovascular function is usually maintained.

General Anesthesia

A patient in a state of general anesthesia will not respond to repeated/loud verbal commands or painful stimulation. The patient’s airway usually requires intervention, and spontaneous ventilation is often inadequate. Additionally, the cardiovascular function may be impaired.

Practical Considerations

The theory of the sedation states presented here helps clearly identify them in nicely organized categories. In practice, it can be more difficult to discern, and it is important to keep in mind that a patient’s level of sedation lies within a continuum: a patient may exhibit characteristics that fit more than one state. For example, a patient may have a purposeful response to verbal and tactile stimulation but also have impaired cardiovascular function. When the sedation level of the patient is not clear, a conservative approach to sedation state identification may be required, along with a rapid intervention response.

Deeper-Than-Intended Sedation

When a moderate sedation state is a goal, it is possible that a patient enters a state deeper than intended (e.g., deep sedation and general anesthesia). The practitioner should be prepared for this case and take the necessary corrective rescue actions.

RAVOC®: A Systematic Approach to Assessing the Patient’s Sedation State

In our Safe Sedation Training courses, we provide aids and organized techniques for sedation practitioners. RAVOC, which stands for Responsiveness, Airway, Ventilation, Oxygenation, and Circulation, is one of the techniques we recommend to clinicians for evaluating the patient during procedural moderate sedation and analgesia. See Figure 1.

Figure 1: RAVOC can be used as an organized method to evaluate the patient’s sedation state.

The idea is to apply RAVOC assessments frequently to ensure the patient remains in a moderate sedation state. When a RAVOC assessment indicates a deeper-than-intended sedation state, then the appropriate rescue techniques may be promptly initiated.

Learn More About Identifying Your Patient’s Sedation State and Rescue Techniques with Safe Sedation Training

We’ve given you a primer on how the sedation practice guidelines define moderate sedation in the context of the sedation continuum and provided a framework for assessing the sedation state. You can read the latest practice guidelines here, and we explore these topics in depth in our Safe Sedation Training (SST) courses.