Description

Monitored Anesthesia Care

Monitored anesthesia care (MAC) is a set of anesthesia services defined by the type of anesthesia personnel present during a procedure, not specifically by the level of anesthesia needed. The American Society of Anesthesiologists (ASA) defined MAC, and the following is derived from the ASA's statements:

"Monitored anesthesia care is a specific anesthesia service for a diagnostic or therapeutic procedure. Indications for monitored anesthesia care include the nature of the procedure, the individual's clinical condition and/or the potential need to convert to a general or regional anesthetic.

Monitored anesthesia care includes all aspects of anesthesia care-a pre-procedure visit, intra-procedure care, and post-procedure anesthesia management. During monitored anesthesia care, the anesthesiologist provides or medically directs a number of specific services, including but not limited to:

• Diagnosis and treatment of clinical problems that occur during the procedure
• Support of vital functions
• Administration of sedatives, analgesics, hypnotics, anesthetic agents or other medications as necessary for patient safety
• Psychological support and physical comfort
• Provision of other medical services as needed to complete the procedure safely

Monitored anesthesia care may include varying levels of sedation, analgesia, and anxiolysis as necessary. The provider of monitored anesthesia care must be prepared and qualified to convert to general anesthesia when necessary. If the individual loses consciousness and the ability to respond purposefully, the anesthesia care is a general anesthetic, irrespective of whether airway instrumentation is required."

Sedation Depth

In 2004 (amended in 2014), ASA defined 4 levels of sedation and analgesia, as shown in Table 1.

Table 1. ASA's Definitions of General Anesthesia and Levels of Sedation and Analgesia

Adapted from American Society of Anesthesiologists (2013).

ASA: American Society of Anesthesiologists.

Because sedation is a continuum, it is not always possible to predict how an individual will respond. Hence, practitioners intending to produce a given level of sedation should be able to rescue individuals whose level of sedation becomes deeper than initially intended. Individuals administering moderate sedation or analgesia (conscious sedation) should be able to rescue individuals who enter a state of deep sedation or analgesia, while those administering deep sedation or analgesia should be able to rescue individuals who enter a state of general anesthesia.

Sedation for Diagnostic and Therapeutic Procedures

Multiple diagnostic and therapeutic procedures performed in the outpatient setting (e.g., endoscopy, colonoscopy, bronchoscopy, interventional pain management procedures) rely on some degree of sedation for anxiolysis and pain control. Regardless of sedation depth, sedation and anesthesia services provided in outpatient settings should be administered by qualified and appropriately trained personnel. Moderate sedation is generally sufficient for many diagnostic and uncomplicated therapeutic procedures. Moderate sedation using benzodiazepines, with or without narcotics, is frequently administered under the supervision of the proceduralist.

According to the ASA's standard for monitoring, MAC should be provided by qualified anesthesia personnel, including physicians and nurse specialists. By this standard, the personnel must be, in addition to the proceduralist, present continuously to monitor the individual and provide anesthesia care. For individuals at high risk of an unsuccessful procedure under moderate sedation, this allows for the safe continuation of the procedure under deep sedation or general anesthesia by trained personnel.

Moderate sedation can be achieved using pharmacologic agents for sedation, anxiolysis, and analgesia. A frequently used combination is an opioid and benzodiazepine (e.g., fentanyl with midazolam) at doses individualized to obtain the desired sedative effect. Other combinations have also been used. While benzodiazepines and opioids can cause respiratory depression, effective reversal agents exist for both.

Propofol has increasingly been used to provide sedation for procedures. It is associated with a rapid onset of action and fast recovery from sedation. However, there are concerns about potential adverse effects and safety when used by non-anesthesiologists. Propofol has the potential to induce general anesthesia, and there is no pharmacologic antagonist to reverse its action. When used as moderate sedation, propofol may be administered by anesthesia personnel or under the direction of the proceduralist. ASA has offered practice guidelines for the provision of sedation by non-anesthesiologists, stating that personnel must be prepared to respond to deep sedation and loss of airway protection should these complications inadvertently occur during sedation.

Regulatory Status

In 1989, propofol Diprivan® (AstraZeneca) was approved by the U.S. Food and Drug Administration (FDA) through the premarket approval process for the induction and maintenance of anesthesia. The current FDA-approved label for Diprivan® states that it is indicated for initiation and maintenance of MAC sedation, combined sedation, and regional anesthesia; the label also states that Diprivan® is indicated for the sedation of adults in the intensive care unit who have been intubated or mechanically ventilated. Moreover, Diprivan® is also approved for induction of general anesthesia in individuals 3 years of age and older and maintenance of general anesthesia in individuals 2 months of age and older.

Many other FDA-approved medications for pain relief, anxiolysis, and sedation may be used in outpatient sedation.

Criteria

The use of monitored anesthesia care may be considered medically necessary for gastrointestinal endoscopy, bronchoscopy, and interventional pain procedures when there is documentation by the proceduralist and anesthesiologist that specific risk factors or significant medical conditions are present.Those risk factors or significant medical conditions include any of the following:

• Increased risk for complications due to severe comorbidity (American Society of Anesthesiologists class III, IV, or V [see Table PG1])
• Morbid obesity (body mass index >40 kg/m²)
• Documented sleep apnea
• Inability to follow simple commands (cognitive dysfunction, intoxication, or psychological impairment)
• Spasticity or movement disorder complicating the procedure
• History or anticipated intolerance to standard sedatives, such as:
• Chronic opioid use
• Chronic benzodiazepine use

• Individuals with active medical problems related to drug or alcohol abuse
• Individuals younger than 18 years or 70 years or older
• Individuals who are pregnant
• Individuals with increased risk for airway obstruction due to anatomic variation, such as:
  • History of stridor
  • Dysmorphic facial features
  • Oral abnormalities (e.g., macroglossia)
  • Neck abnormalities (e.g., neck mass)
  • Jaw abnormalities (e.g., micrognathia)
• Acutely agitated, uncooperative individuals
• Prolonged or therapeutic gastrointestinal endoscopy procedures requiring deep sedation

Table PG1: ASA's Physical Status Classification System

ASA: American Society of Anesthesiologists

The use of monitored anesthesia care is considered not medically necessary for gastrointestinal endoscopic, bronchoscopic, or interventional pain procedures in individuals at average risk related to use of anesthesia and sedation.

Procedure Codes

Diagnosis Codes

Professional Statements and Societal Positions Guidelines

Practice Guidelines and Position Statements

American Society of Anesthesiologists

In 2014, the American Society of Anesthesiologists (ASA) updated its statement on the safe use of propofol:

"The Society believes that the involvement of an anesthesiologist in the care of every individual undergoing anesthesia is optimal. However, when this is not possible, non-anesthesia personnel who administer propofol should be qualified to rescue individuals whose level of sedation becomes deeper than initially intended and who enter, if briefly, a state of general anesthesia."

"Rescue" was defined as correcting "adverse physiologic consequences of the deeper-than-intended level of sedation (such as hypoventilation, hypoxia, and hypotension) and returns the individual to the originally intended level."

In 2016, ASA updated its statement on anesthetic care during interventional pain procedures. ASA indicated that:

"Many individuals can undergo interventional pain procedures without the need for supplemental sedation in addition to local anesthesia. For most individuals who require supplemental sedation, the physician performing the interventional pain procedure(s) can provide moderate (conscious) sedation as part of the procedure. For a limited number of individuals, a second provider may be required to manage moderate or deep sedation or, in selected cases other anesthesia services….

Significant anxiety may be an indication for moderate (conscious) sedation or anesthesia services. In addition, procedures that require the individual to remain motionless for a prolonged period of time and/or remain in a painful position may require sedation or anesthesia services. Examples of such procedures include but are not limited to sympathetic blocks (celiac plexus, paravertebral and hypogastric), chemical or radiofrequency ablation, percutaneous discectomy, trial spinal cord stimulator lead placement, permanent spinal cord stimulator generator and lead implantation, and intrathecal pump implantation. Major nerve/plexus blocks are performed less often in the chronic pain clinic, but the Committee believes that these blocks may more commonly require moderate (conscious) sedation or anesthesia services (e.g., brachial plexus block, sciatic nerve block, and continuous catheter techniques)."

In 2014, ASA updated its statement on respiratory monitoring during endoscopic procedures. The statement advised that "Monitoring for exhaled carbon dioxide should be conducted during endoscopic procedures in which sedation is provided with propofol alone or in combination with opioids and/or benzodiazepines, and especially during these procedures on the upper gastrointestinal tract."

American Society for Gastrointestinal Endoscopy

Guidelines on sedation during gastrointestinal endoscopy were released in 2018 by the American Society for Gastrointestinal Endoscopy (ASGE). The guidelines stated that anesthesia provider assistance during gastrointestinal endoscopy should be considered in the following situations: prolonged or therapeutic endoscopic procedures requiring deep sedation, anticipated intolerance to standard sedatives, increased risk for adverse event because of severe comorbidity (ASA class IV or V), and increased risk for airway obstruction because of anatomic variant. The guidelines made the following recommendations for the use of propofol during endoscopies:

• "A sedation team with appropriate education and training [including] at least 1 person … qualified in advanced life support skills….
• Trained personnel [for] uninterrupted monitoring of individual's clinical and physiologic parameters….
• Physiologic monitoring must include pulse oximetry, electrocardiography, and intermittent blood pressure measurement. Monitoring oxygenation by pulse oximetry is not a substitute for monitoring ventilatory function. Capnography should be considered because it may decrease the risks during deep sedation…
• Personnel should have the ability to rescue a individual who becomes unresponsive or unable to protect his or her airway or who loses spontaneous respiratory or cardiovascular function.
• Age-appropriate equipment for airway management and resuscitation must be immediately available.
• A physician should be present throughout propofol sedation and remain immediately available until the individual meets discharge criteria."

In 2015, ASGE published quality indicators for all gastrointestinal endoscopic procedures. Specific to this evidence review, ASGE stated: "Individuals administering moderate sedation should be able to rescue individuals who enter a state of deep sedation, whereas those administering deep sedation should be able to rescue patients who enter a state of general anesthesia."

In 2013, ASGE published guidelines for endoscopic modification for geriatric individuals. Specific to this evidence review, ASGE recommended "standard monitoring procedures in the elderly during moderate sedation with heightened awareness of this population's increased response to sedatives."

In 2014, ASGE issued guidelines on the safety of the endoscopy unit, which made several recommendations on procedural sedation: "Staff Recommendations for intra-procedure care based on level of sedation

• No sedation-One assistant …other than the physician performing the procedure should be present to assist with the technical aspects of the procedure.
• Moderate sedation (also known as conscious sedation)-Sedation should be directed by a physician who is credentialed and privileged to do so and can be administered by an RN. During the period in which the individual is sedated, the RN must monitor the individual for vital sign changes, hypoxemia and comfort. The RN may assist with minor, interruptible tasks. In the event that more intense technical assistance is required, a second assistant (RN, LPN, or UAP [unlicensed assistive personnel]) should be available to join the care team for the technical aspects of the procedure.
• Deep sedation-Most institutions require that deep sedation be administered by ananesthesiaprofessional such as an anesthesiologist, Certified Registered Nurse Anesthetist (CRNA), or Anesthesiologist Assistant who is credentialed and privileged to do so. In this situation, theanesthesiaprovider should be responsible for administering sedation and monitoring the individual. A second staff person (RN, LPN, or UAP) is required to assist with technical aspects of the procedure."

"Recommendations for Individual Monitoring”

• All individuals undergoingendoscopyshould be monitored, the frequency of which depends on procedural and individual factors (e.g., type of sedation, duration and complexity of procedure, individual’s condition). At a minimum, monitoring should be performed before the procedure, after administration of sedatives, at regular intervals during the procedure, during initial recovery, and just before discharge.
• Units should have procedures in place to rescue individuals who are sedated deeper than intended.
• When the target level is moderate sedation (also known as conscious sedation):
  • The individual assigned responsibility for patient monitoring may perform brief, interruptible tasks.
  • Minimal monitoring requirements include electronic assessment of blood pressure, respiratory rate, heart rate, and pulse oximetry combined with visual monitoring of the individual's level of consciousness and discomfort.
• Currently, there are inadequate data to support the routine or required use of capnography during endoscopic procedures in adults when moderate sedation is the target.

• When deep sedation is targeted:
• The individual responsible for patient monitoring must be dedicated solely to that task and may not perform any other function during the procedure.
• The use of capnography in EUS [endoscopic ultrasound], ERCP [endoscopic retrograde cholangiopancreatography], and colonoscopy to assess the adequacy of ventilation may reduce the incidence of hypoxemia and apnea, but its impact on the frequency of other sedation-related adverse events such as bradycardia and hypotension is unknown. As such, capnography may be considered for the performance ofendoscopyunder deep sedation. However, there is no safety data to date to support the universal use of capnography in such cases.
• Documentation of the clinical assessments and monitoring data during sedation and recovery is required."

In 2009, ASGE-along with the American Association for the Study of Liver Diseases, American College of Gastroenterology, and American Gastroenterological Association-issued a joint position statement on non-anesthesiologist administration of propofol (NAAP) for gastrointestinal endoscopy. The societies found that NAAP was as safe and effective as anesthesiologist-administered propofol. They asserted that proper training and proper individual selection were necessary for the safe practice of NAAP sedation.

European Society of Gastrointestinal Endoscopy et al

The European Society of Gastrointestinal Endoscopy, as well as the European Society of Gastroenterology and Endoscopy Nurses and Associates, updated their guidelines on NAAP in 2015. Table 2 summarizes the main recommendations.

Table 2. Recommendations on NAAP for GI Endoscopy

ASA: American Society of Anesthesiologists; GI: gastrointestinal; NAAP: non-anesthesiologist-administered propofol; QOE: quality of evidence; SOR: strength of recommendation.

^aASA class ≥3, with a Mallampati's class ≥3 or other conditions that put them at risk of airway obstruction, in individuals receiving significant amounts of narcotic analgesics, or in long-lasting procedures.

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