Twilight Anesthesia Protocol for Minor Procedures
For minor procedures, twilight anesthesia (moderate procedural sedation) should be administered using titrated benzodiazepines and opioids (or propofol-based regimens), with continuous monitoring by a dedicated observer separate from the proceduralist, following the 2018 ASA guidelines for moderate procedural sedation. 1
Pre-Procedure Requirements
Patient Assessment and Preparation
- Conduct focused assessment examining airway anatomy (facial/neck anatomy, mouth opening, thyromental distance, obesity with thick neck, obstructive sleep apnea history), cardiovascular status, respiratory function, and current medications including anticoagulants, opioids, and benzodiazepines 2
- Document ASA Physical Status classification, as ASA-PS III-IV patients require approximately 80% dose reductions and slower titration 2
- Inform patients or legal guardians of benefits, risks, limitations of moderate sedation and possible alternatives before the procedure 1
- Instruct patients not to drink fluids or eat solid foods for sufficient time to allow gastric emptying before the procedure 1
- On procedure day, assess time and nature of last oral intake and evaluate pulmonary aspiration risk 1
- In urgent/emergent situations where complete gastric emptying is not possible, do not delay moderate procedural sedation based on fasting time alone 1
Personnel and Equipment Standards
Staffing Requirements
- A designated individual other than the practitioner performing the procedure must be present to monitor the patient throughout the procedure 1
- This individual must be trained in recognition of apnea and airway obstruction and authorized to seek additional help 1
- The designated monitor may assist with minor, interruptible tasks once the patient's sedation level and vital signs have stabilized, provided adequate monitoring continues 1
- At least one individual capable of establishing a patent airway and providing positive pressure ventilation must be present in the procedure room 1
Emergency Equipment (Immediately Available)
- Appropriately sized equipment for establishing a patent airway 1
- Suction apparatus 1
- Advanced airway equipment 1
- Positive pressure ventilation device 1
- Supplemental oxygen delivery systems 1
- Pharmacologic antagonists for benzodiazepines (flumazenil) and opioids (naloxone) in the procedure suite 1
- Functional defibrillator or automatic external defibrillator 1
Medication Protocols
Benzodiazepine-Opioid Combination (Traditional Approach)
Midazolam Dosing:
- **Healthy adults <60 years:** Titrate slowly to desired effect (e.g., slurred speech initiation). Give no more than 2.5 mg over at least 2 minutes. Wait additional 2+ minutes to evaluate sedative effect. If further titration needed, use small increments. Total dose >5 mg rarely necessary 3
- Adults ≥60 years, debilitated, or chronically ill: Give no more than 1.5 mg over at least 2 minutes. Wait additional 2+ minutes to evaluate. Additional titration at no more than 1 mg over 2 minutes. Total doses >3.5 mg not usually necessary 3
- With narcotic premedication or CNS depressants: Patients require approximately 30% less midazolam than unpremedicated patients (50% less in elderly/chronically ill) 3
- Maintenance: Additional doses of 25% of initial dose to maintain sedation level, by slow titration 3
Fentanyl Combination:
- When combined with midazolam, fentanyl provides analgesia component for conscious sedation 4
- Administer combinations as appropriate for the procedure, giving each component individually to achieve desired effect 1
Propofol-Based Regimen (Alternative)
Propofol for Sedation:
- Titrate in increments of approximately 25-50 mg (2.5-5 mL) boluses 5
- Allow adequate interval (3-5 minutes) between dose adjustments to assess clinical effects 5
- Generally, rates of 50-100 mcg/kg/min should be achieved during maintenance to optimize recovery times 5
- Elderly, debilitated, or ASA-PS III-IV patients: Require approximately 1-1.5 mg/kg (approximately 20 mg every 10 seconds). Avoid rapid bolus as this increases likelihood of cardiorespiratory depression including hypotension, apnea, airway obstruction, and/or oxygen desaturation 5
Propofol-Fentanyl Combination:
- Mean onset to sedation: 52.5 seconds 4
- Mean recovery interval: 3 minutes 43 seconds 4
- Mean total propofol dose: 5.83 mg/kg 4
- Provides quick, effective conscious sedation with minimal side effects 4
Dexmedetomidine Option
- May be administered as alternative to benzodiazepine sedatives on case-by-case basis 1
Monitoring Protocol
Continuous Monitoring Requirements
- Level of consciousness: Monitor patient's response to verbal commands at 5-minute intervals during moderate sedation, except in patients unable to respond appropriately (age, development) or during procedures where movement detrimental 1
- During procedures where verbal response not possible (oral surgery, restorative dentistry, upper endoscopy): Check patient's ability to give "thumbs up" or other indication of consciousness in response to verbal or tactile (light tap) stimulation 1
- Ventilatory function: Continually monitor by observation of qualitative clinical signs 1
- Oxygenation: Continuous pulse oximetry 1
- Blood pressure: Determine before sedation initiated. Once moderate sedation established, continually monitor (e.g., at 5-minute intervals) during procedure 1
- Heart rate: Continually monitor during procedure 1
- Electrocardiographic monitoring: Use during moderate sedation in patients with clinically significant cardiovascular disease or those undergoing procedures where dysrhythmias anticipated 1
Documentation Requirements
Record level of consciousness, ventilatory and oxygenation status, and hemodynamic variables at minimum: (1) before sedative/analgesic agents, (2) after administration, (3) at regular intervals during procedure, (4) during initial recovery, and (5) just before discharge 1
Device Alarms
Set alarms to alert care team to critical changes in patient status 1
Recovery and Discharge
Recovery Phases
- First-stage recovery: Until patient awake, protective airway reflexes returned, and pain controlled. Should occur in recovery area with appropriate facilities and staffing 1
- Second-stage recovery: From when patient steps off trolley until ready for discharge. Should take place in area adjacent to procedure area, equipped and staffed to deal with common postoperative problems (nausea, pain) and emergencies 1
Discharge Criteria
- Observe patients in appropriately staffed area until near baseline consciousness and no longer at increased risk for cardiorespiratory depression 2
- Monitor at regular intervals during procedure and recovery 2
- Continue oxygenation monitoring until no risk for hypoxemia 2
Post-Discharge Instructions
- Advise not to drink alcohol, operate machinery, or drive for 24 hours after sedation 1
- Provide written instructions including warning signs of possible complications and when to seek help 1
- If local anesthetic agents applied to airway, laryngeal reflexes may be depressed for up to one hour; children should not drink during this period due to increased aspiration risk 1
Common Pitfalls and Safety Considerations
Critical Safety Points
- Titration is essential: Adequate time to achieve peak CNS effect (3-5 minutes) must be allowed between doses to minimize oversedation potential 3
- Avoid rapid boluses: Especially in elderly, debilitated, or ASA-PS III-IV patients, as this increases cardiorespiratory depression risk 5
- Drug interactions: Other CNS depressants (sedatives, anesthetics, opioids) can increase CNS depression induced by sedation agents 5
- Individual variability: Patient response varies with age, physical status, concomitant medications, but may also vary independent of these factors 3
- Respiratory depression protocol: Includes stimulating patient, administering supplemental oxygen, providing positive pressure ventilation, and administering reversal agents if necessary 2