What initial target‑controlled infusion (TCI) effect‑site concentrations of propofol and remifentanil should be used for a 68‑year‑old woman, 59 kg, 152 cm, with an ejection fraction of 47 % undergoing coronary angiography?

Target-Controlled Infusion Dosing for Propofol and Remifentanil in Coronary Angiography

For this 68-year-old woman with EF 47% undergoing coronary angiography, start with remifentanil effect-site concentration of 2–3 ng/mL and propofol effect-site concentration of 0.5–1 µg/mL using TCI pumps, avoiding bolus dosing to minimize respiratory depression risk. 1

Initial TCI Settings

Remifentanil:

• Effect-site target: 2–3 ng/mL 1
• Avoid bolus administration entirely—the Difficult Airway Society specifically warns against bolus dosing due to marked respiratory depression risk 1
• This concentration range provides adequate analgesia while minimizing respiratory compromise 1

Propofol:

• Effect-site target: 0.5–1 µg/mL 1
• This lower range is appropriate when combined with remifentanil due to synergistic effects 1
• The combination allows 50–75% reduction in propofol requirements compared to monotherapy 1

Critical Safety Considerations for This Patient

Reduced ejection fraction (47%) requires heightened vigilance:

• Propofol causes dose-dependent decreases in cardiac output, systemic vascular resistance, and arterial pressure 2
• The combination produces synergistic respiratory depression beyond either agent alone 1
• Her small body size (59 kg) and advanced age (68 years) increase sensitivity to both agents 3, 4

Mandatory monitoring throughout the procedure:

• Continuous pulse oximetry, blood pressure (every 2–5 minutes minimum), and heart rate 1
• Capnography for early hypoventilation detection 1
• Maintain vascular access throughout and until cardiorespiratory depression risk resolves 1
• Supplemental oxygen administration is mandatory 1

Titration Strategy

Adjust concentrations slowly:

• Allow adequate time between adjustments (2–5 minutes) to assess peak effect before additional dosing 1
• Titrate remifentanil in 25–50% increments of the infusion rate 1
• Titrate propofol effect-site target in 0.1–0.2 µg/mL increments 1
• Target moderate rather than deep sedation to improve safety profile 1

Expected Total Drug Requirements

For a typical coronary angiography procedure:

• Total propofol: approximately 35–100 mg (significantly less than the 200–300 mg required with propofol alone) 1
• Remifentanil: continuous infusion maintained at target concentration throughout procedure 1
• The combination provides superior procedural conditions with improved patient satisfaction 1

Common Pitfalls to Avoid

Do not use bolus dosing:

• Bolus administration of either drug markedly increases respiratory depression risk 1
• TCI systems provide gradual titration that is safer than manual bolus techniques 1

Do not underestimate cardiovascular effects:

• Her borderline EF (47%) places her at higher risk for propofol-induced hypotension 2
• Have vasopressors immediately available 4
• Consider reducing initial propofol target to 0.5 µg/mL in this patient 1

Do not forget analgesic requirements:

• Propofol provides zero analgesic properties 1, 2
• Remifentanil is essential for the painful aspects of arterial access and catheter manipulation 1

Reversal and Emergency Equipment

Immediately available:

• Naloxone for remifentanil reversal 1
• Airway management equipment including bag-mask ventilation 5
• Vasopressors for hypotension management 4

Alternative Dosing Approach (If TCI Unavailable)

If TCI pumps are not available, an alternative regimen based on infusion rates:

• Remifentanil: 0.05 µg/kg/min continuous infusion (approximately 3 µg/min for this 59 kg patient) 1
• Propofol: small boluses of 10–15 mg every 20–30 seconds until adequate sedation, then maintain with minimal additional doses 2
• This approach is less precise than TCI and carries higher risk of oversedation 1