What remifentanil effect‑site concentration (Ce, Minto model) should be targeted to achieve a smooth extubation in a patient under sevoflurane anesthesia who has received rocuronium and will be reversed with sugammadex?

Remifentanil Effect-Site Concentration for Smooth Extubation

Target a remifentanil effect-site concentration (Ce) of 1.70 ng/mL using the Minto model to achieve smooth extubation without coughing in 95% of patients under sevoflurane anesthesia. 1

Evidence-Based Recommendation

The most recent and highest quality study specifically addressing this question used the up-and-down method with isotonic regression to determine precise remifentanil concentrations for cough suppression during emergence from sevoflurane anesthesia 1. This study found:

• EC50: 1.42 ng/mL (95% CI: 1.28-1.56 ng/mL) - prevents coughing in 50% of patients
• EC95: 1.70 ng/mL (95% CI: 1.67-2.60 ng/mL) - prevents coughing in 95% of patients

For clinical practice, target 1.70 ng/mL Ce to ensure smooth extubation in the vast majority of patients.

Clinical Implementation Strategy

Timing and Technique

The key to success lies in removing the hypnotic component (sevoflurane) well in advance of extubation while maintaining appropriate remifentanil titration 2. This approach provides the beneficial combination of a tube-tolerant patient who is fully awake and obeys commands.

Dosing Considerations

The Difficult Airway Society guidelines acknowledge that a broad range of remifentanil doses have been described in the literature 2. The goal is to avoid:

• Too low a dose → coughing and hemodynamic instability
• Too high a dose → delayed emergence and apnea

Neuromuscular Blockade Reversal

Since your patient received rocuronium and will be reversed with sugammadex, ensure adequate reversal before extubation 3:

• At TOF count ≥2: Administer sugammadex 2.0 mg/kg for reversal within 3-5 minutes
• At TOF count of 4: Can use 1.0 mg/kg sugammadex (slower, ~5 minutes)
• Monitor TOF ratio ≥0.9 before extubation to prevent residual paralysis

Important Caveats

Hemodynamic Stability

The study found comparable emergence and recovery times between cough suppression and cough groups, with no significant hemodynamic compromise 1. However, patients in the cough suppression group received higher total remifentanil doses, so monitor for:

• Respiratory depression
• Bradycardia
• Hypotension

Patient-Specific Factors

Several factors influence the required remifentanil dose 2:

• Patient characteristics (age, comorbidities)
• Surgical procedure
• Anesthetic technique used intraoperatively

For elderly patients: Consider that they may require dose adjustments, though the primary study establishing the 1.70 ng/mL target included patients up to 70 years old 1.

Respiratory Monitoring

Critical: Maintain vigilant monitoring during emergence. The remifentanil concentration that prevents coughing may also cause transient apnea. Be prepared to provide:

• Assisted ventilation if needed
• Supplemental oxygen
• Immediate airway support

Clinical Algorithm

1. Discontinue sevoflurane 10-15 minutes before planned extubation
2. Maintain remifentanil TCI at 1.70 ng/mL Ce (Minto model)
3. Verify adequate neuromuscular reversal (TOF ratio ≥0.9) with sugammadex
4. Ensure patient is awake and following commands
5. Perform gentle suctioning under direct vision if needed
6. Extubate when patient tolerates tube without coughing
7. Discontinue remifentanil immediately after extubation
8. Monitor closely for 5-10 minutes post-extubation for respiratory depression

This concentration of 1.70 ng/mL represents the most evidence-based target for smooth extubation in neurointervention patients, where avoiding coughing-induced intracranial hypertension is particularly critical 1.