What is the recommended anesthetic regimen for labrum repair under Monitored Anesthesia Care (MAC)?

Anesthetic Management for Labrum Repair Under Monitored Anesthesia Care (MAC)

For labrum repair under MAC, a combination of propofol infusion with regional anesthesia (interscalene block) is recommended, supplemented with dexmedetomidine for sedation and analgesia while maintaining spontaneous breathing. 1

Recommended Anesthetic Regimen

Pre-procedure Assessment

• Identify high-risk patients, including elderly (>60 years) and those with sleep-disordered breathing who may require additional monitoring 2
• Assess for reactive airway disease or asthma which may influence medication selection 1

Regional Anesthesia Component

• Interscalene brachial plexus block should be performed as the primary anesthetic for shoulder labrum repair 1
• Consider supplementing with local anesthetic infiltration at surgical site for additional pain control 3

Sedation Strategy

• Primary sedation options:

  • Propofol infusion (0.2-1.0 μg/kg/h) titrated to targeted level of sedation (Observer's Assessment of Alertness/Sedation Scale ≤4) 4
  • Dexmedetomidine (loading dose 0.5-1 μg/kg over 10 minutes, followed by 0.2-0.7 μg/kg/h) provides better analgesia and less respiratory depression than propofol alone 4, 5

• Alternative combination approach:

  • Ketofol (ketamine-propofol admixture) has shown effectiveness for shoulder arthroscopy and labrum repair under MAC, particularly beneficial when airway access is limited in beach chair position 1

Monitoring Requirements

• Standard monitoring must include ECG, SpO2, and NIBP throughout the procedure 3
• Capnography should be used whenever there is loss of response to verbal contact 3
• Processed EEG monitoring (BIS) is recommended to titrate sedation depth, particularly when using propofol with opioids 2
• Target BIS level of approximately 50 to maintain appropriate sedation while avoiding excessive depth 2

Medication Management

Opioid Supplementation

• Fentanyl (0.5-1 μg/kg) or remifentanil can be added to propofol for improved analgesia 6
• Tramadol via patient-controlled analgesia (PCA) can be combined with either propofol or dexmedetomidine for additional analgesia 5

Considerations for Specific Patient Populations

• For elderly patients (>60 years):
  • Reduce propofol dosage as pharmacokinetic changes lead to higher peak plasma concentrations 7
  • Monitor depth of anesthesia closely to avoid hypotension and postoperative delirium 2

Potential Complications and Management

Respiratory Complications

• Airway intervention may be required in up to 11% of MAC cases 6
• Dexmedetomidine has lower incidence of clinically significant respiratory depression compared to propofol with midazolam 4

Hemodynamic Management

• Monitor for bradycardia and hypotension, particularly with dexmedetomidine 4, 5
• Consider lower dexmedetomidine doses (0.5 μg/kg loading) to minimize hemodynamic effects while maintaining adequate sedation 4

Wake-Up Testing

• If intraoperative assessment of repair is needed, propofol combined with opioids provides more effective wake-up testing than propofol alone 6

Postoperative Considerations

• Assess for adequate recovery from sedation before discharge 3
• Monitor for postoperative nausea and vomiting, which may be reduced with dexmedetomidine compared to propofol-only regimens 4, 5

MAC with appropriate sedation and regional anesthesia provides adequate conditions for labrum repair while avoiding the risks associated with general anesthesia, particularly in the beach chair position where airway access is limited 1.