Monitored Anesthesia Care or Twilight Sleep Explained

Monitored Anesthesia Care (MAC), also known as conscious sedation or twilight sleep, is administered through an IV to make a patient sleepy and calm during a procedure. The patient is typically awake but groggy and can follow instructions as needed.

Medications that might be used during monitored anesthesia include:

• Diprivan (propofol)
• Benzodiazepines like Versed (midazolam) and others
• Opioids (fentanyl, Demerol, and others)
• Ketamine, which is often used in pediatric cases

MAC is used for outpatient procedures where patients are expected to go home after the anesthesia has completely worn off.

What Does Monitored Anesthesia Feel Like?

The level of sedation provided with this type of anesthesia ranges from light sedation to deep sedation. The patient may feel silly and a little sleepy, or under heavier doses may be mostly asleep.

Minimal Sedation

In light sedation, patients can speak, hear things around them, answer questions, and follow commands. They are aware of the procedure but not in pain and typically don't feel anxious about what is happening.

Moderate Sedation

Moderate sedation, also called conscious sedation, causes patients to feel more sleepy than under light sedation, but they are not necessarily asleep. Awareness is generally reduced under moderate sedation, but patients might remember some aspects of the procedure. They can respond to commands.

Deep Sedation

With heavier sedation, the patient is breathing on their own but is unaware of their surroundings and typically isn't "awake." This type of anesthesia is different from general anesthesia because the patient is not chemically paralyzed, nor do they require assistance with breathing. The vital signs are closely monitored to ensure stability throughout the procedure.

One medication commonly used for this type of sedation is propofol, also known as the brand name Diprivan, which is given through an IV and looks remarkably similar to milk. This medication wears off quickly (less than ten minutes for most people), so the patient can wake shortly after the procedure.

What to Expect

Because the level of sedation varies, the process is monitored by a specially trained healthcare professional who is always present to continuously monitor the patient's vital signs and maintain or adjust the level of sedation as needed. Healthcare professionals who can perform monitored anesthesia care vary by the level of anesthesia as well as state and institutional policy, but may include:

• Anesthesiologists
• Anesthesia assistant or technician
• Certified anesthesia technologist
• Certified registered nurse anesthetists (CRNAs)
• Dentists

At a minimum, vital signs are measured with a blood pressure cuff and an oxygen monitor. Typically, electrodes are placed on the chest to monitor the patient's heart rate and EKG throughout the procedure.

When It's Used

This type of sedation is frequently used with minor surgical and dental procedures and can be combined with local or regional anesthesia to decrease pain. Some examples of procedures that might use monitored anesthesia care include:

• Bronchoscopy, a procedure that lets healthcare providers visualize the airways and lungs
• Colonoscopy, which lets providers check the colon
• Esophagogastroduodenoscopy or EGD, which visualizes the upper part of the GI tract
• Dental surgery, in some cases for patients with significant dental anxiety
• Biopsy, particularly more invasive biopsy locations
• Orthopedics, such as setting a bone fracture

What Are the Side Effects of Monitored Anesthesia?

Patients having conscious sedation often have fewer side effects than those who have general anesthesia. The most common side effect is nausea, but some patients do experience both nausea and vomiting. If you have experienced nausea or vomiting after anesthesia in the past, be sure to tell your anesthesia provider so medication can be given to help prevent it from happening again.

There are potentially serious side effects of monitored anesthesia care, but these are rare. They might include:

• Low oxygen levels
• Low blood pressure
• Inadequate sedation
• Irregular heartbeat
• Anaphylaxis
• Aspiration (breathing anything other than air into the lungs)

Summary

Monitored anesthesia care is crucial to keeping patients comfortable during specific medical or dental procedures. A bad experience during a healthcare encounter can hinder future healthcare, so having a good experience is crucial to maintaining good health.

Different drugs are used to provide different levels of sedation, depending on the procedure being performed. If you have any questions about monitored anesthesia care, ask your healthcare provider before any procedures.