N. otes on Ambulatory Anesthesia for ANT 320

Overview of Ambulatory Anesthesia

  • Ambulatory anesthesia involves anesthesia provided for outpatient surgeries, allowing patients to return home the same day.

Increased Use of Outpatient Surgeries

  • Proportion of outpatient surgeries in the U.S.:

    • Increased from 50% in 1996 to 66% in 2006.

  • Most common procedures:

    • Endoscopy

    • Cataract surgery

Monitored Anesthesia Care (MAC)

  • Typically used for endoscopy and cataract surgeries.

  • Requires both the anesthesia provider's preparation for and qualification to convert to general anesthesia if needed.

Awareness and Communication

  • Patients should accept:

    • Potential awareness during the procedure.

    • The ability to tolerate required positioning for surgery.

    • In some cases, communicate with the surgeon during the procedure.

Techniques in Ambulatory Anesthesia

  • Successful MAC often involves:

    • Combination of anesthetic agents, specifically:

    • Sedative hypnotics

    • Analgesic agents

  • Preference for medications with minimal side effects and short duration for efficient and rapid recovery.

Common Medications Used

  • Propofol

    • Short-acting intravenous sedative-hypnotic.

    • Used for induction and maintenance of sedation.

  • Benzodiazepines (e.g., Midazolam)

    • Used prior to induction.

    • Provides anxiolysis and amnesia.

    • Short elimination half-life but delayed emergence with larger doses.

    • Typically administered in small doses for comfort during anesthesia.

  • Opioids (e.g., Fentanyl)

    • Provides additional analgesia.

    • Common side effects include:

    • Bradycardia

    • Dose-dependent respiratory depression

    • Nausea and vomiting

    • Large doses should be avoided.

  • Ketamine

    • Used in small doses for MAC; larger doses for general anesthesia.

    • Benefits for asthmatic patients due to bronchodilator properties.

    • Minimal respiratory effects compared to other sedatives and opioids.

Respiratory Function and Sedative Hypnotics

  • Dose-dependent adverse effects associated with sedative-hypnotics include:

    • Respiratory depression.

    • Suppression of normal airway reflexes.

    • Increased upper airway resistance.

Anesthetic Options for Ambulatory Surgery

  • Options include:

    • General anesthesia.

    • Regional or neuraxial anesthesia (spinal and epidural).

    • Local anesthesia.

Specific Anesthetic Techniques

  • Spinal Anesthesia:

    • Appropriate for surgeries on lower extremities or pelvis.

    • Local anesthetic injected into the spinal fluid.

  • Epidural Anesthesia:

    • Involves catheter placement in the epidural space,

    • Local anesthetic administered prior to surgery.