What are the guidelines for monitored anesthesia care?

Monitored Anesthesia Care Guidelines

Core Definition and Requirements

Monitored anesthesia care (MAC) is a planned procedure requiring continuous presence of an appropriately trained anesthesia provider with standard monitoring including pulse oximetry, non-invasive blood pressure, ECG, and capnography whenever there is loss of response to verbal contact. 1

Minimum Monitoring Standards

The Association of Anaesthetists establishes these as essential minimum monitoring for all MAC procedures, regardless of duration or location: 1

• Pulse oximeter with plethysmograph 1
• Non-invasive blood pressure (NIBP) 1
• ECG monitoring 1
• Temperature (before procedure and every 30 minutes) 1
• Waveform capnography (mandatory whenever loss of response to verbal contact occurs) 1

Critical Monitoring Caveat

Capnography must be used during procedural sedation whenever there is loss of response to verbal contact. 1 This is non-negotiable as it provides early detection of respiratory depression and hypoventilation. 2

Personnel Requirements

An appropriately trained and experienced anesthesia provider must be present continuously throughout the entire procedure to ensure patient safety. 2 This continuous presence is mandatory and cannot be delegated during the actual sedation period. 2

Sedation Administration Protocol

Initiation Phase

For MAC sedation initiation, use either: 3

• Infusion method: Propofol 100-150 mcg/kg/min for 3-5 minutes, titrated to effect 3
• Slow injection method: Propofol approximately 0.5 mg/kg administered over 3-5 minutes 3

Critical warning: Rapid bolus administration must never be used, especially in elderly, debilitated, or ASA-PS III-IV patients, as this causes dangerous cardiorespiratory depression including hypotension, apnea, airway obstruction, and oxygen desaturation. 3

Maintenance Phase

Variable rate infusion is strongly preferred over intermittent bolus dosing. 3 Typical maintenance rates: 3

• Initial 10-15 minutes: 25-75 mcg/kg/min (1.5-4.5 mg/kg/h) 3
• Subsequently: Decrease to 25-50 mcg/kg/min, adjusted to clinical response 3
• Allow approximately 2 minutes for peak drug effect when titrating 3

Always titrate downward in the absence of light sedation signs until mild responses to stimulation are obtained to avoid excessive sedation. 3

Special Population Adjustments

Elderly, Debilitated, or ASA-PS III-IV Patients

• Reduce propofol dosage to approximately 80% of usual adult dose 3
• Administration must occur over 3-5 minutes minimum 3
• Consider processed EEG monitoring to avoid excessive anesthetic depth 4
• Never use rapid bolus techniques 3

Alarm Management

All alarm limits must be set to patient-specific values before use, and audible alarms must be enabled during the procedure. 1 The existing default alarm settings are frequently inappropriate and should be adjusted. 1

Departments should establish consensus-based alarm limits and standardize these across monitors to improve safety. 1

Documentation Requirements

Maintain an accurate anesthetic record with monitoring data documented at least every 5 minutes, including: 2

• Heart rate, blood pressure, SpO2, and ETCO2 2
• All medications with timing and dosages 2
• Any complications and interventions 2

Electronic anesthetic record systems integrated into the hospital's electronic health record are strongly recommended. 1, 2

Equipment Preparation

The anesthesiologist must check all equipment before use and be familiar with its operation. 1 This includes: 1

• Verifying infusion devices are functioning with alarms enabled 1
• Ensuring IV cannula visibility throughout the procedure when practical 1
• Confirming oxygen supply adequacy 1

Blood Glucose Monitoring

Capillary blood glucose monitoring must be immediately accessible in every location where MAC is performed. 1 For patients with treated diabetes: 1

• Measure blood glucose before induction 1
• Monitor at least hourly during the procedure 1
• Target range: 6-10 mmol/L (upper limit of 12 mmol/L may be tolerated) 1

Recovery and Transfer Standards

Continue monitoring through recovery until the patient is fully responsive. 2 If transferring an anesthetized or sedated patient: 1

• Maintain same monitoring standards as in the procedure location 1
• Use capnography if any airway device remains in place 1
• Ensure adequate oxygen supply for transfer duration 1

Common Pitfalls to Avoid

Airway obstruction risk: Have airway equipment immediately available and position patient to optimize airway access for emergency intervention. 2 Continuous monitoring of respiratory function is critical. 2

Inadequate regional block: If the regional block is inadequate, excessive sedation may be required, potentially negating MAC safety advantages. 4 MAC provides poor blockade of stress response unless the regional block provides profound anesthesia. 4

Fire safety: When electrocautery is used near the airway, configure surgical drapes to prevent oxygen accumulation, moisten sponges near ignition sources, and notify the surgeon when ignition sources are near oxygen-enriched atmospheres. 2