Recommended Anesthetic Regimen for Maintenance Phase of Surgery
The recommended anesthetic regimen for the maintenance phase of surgery should include short-acting inhalational anesthetics such as sevoflurane or desflurane in oxygen-enriched air, or total intravenous anesthesia (TIVA) with propofol, combined with adjuncts such as dexmedetomidine and short-acting opioids, while maintaining appropriate depth of anesthesia monitoring. 1, 2
General Anesthetic Maintenance Options
- Short-acting inhalational anesthetics (sevoflurane or desflurane) in oxygen-enriched air are commonly recommended for maintenance of anesthesia 1
- Total intravenous anesthesia (TIVA) using propofol with target-controlled infusion pumps is an effective alternative, particularly beneficial for patients susceptible to postoperative nausea and vomiting 1, 3
- For propofol maintenance, dosages of 50-200 mcg/kg/min are typically recommended, with rates adjusted based on clinical response and monitoring 4
- There is no strong evidence to recommend one technique (inhalational vs. intravenous) over another in terms of postoperative outcomes 1, 3
Adjunctive Agents
- Dexmedetomidine (0.5 μg/kg/h) is recommended as an adjunct during maintenance phase as it:
- Short-acting opioids (fentanyl, alfentanil, or remifentanil infusion) should be incorporated for analgesia during maintenance 1, 2
- Neuromuscular blocking agents should be titrated using neuromuscular monitoring to maintain appropriate surgical conditions 1
Monitoring During Maintenance
- Bispectral index (BIS) monitoring is recommended to titrate anesthetic depth to a target of 40-60, especially important in elderly patients to prevent excessive depth and postoperative delirium 1, 2
- Goal-directed fluid therapy should be implemented to optimize cardiac performance and improve oxygen delivery during maintenance 1
- Monitoring of cerebral oxygen saturation may be beneficial to detect cerebral hypoperfusion and prevent postoperative neurocognitive dysfunction, particularly in cardiac surgery 1
Procedure-Specific Considerations
For Thoracic Surgery:
- Intraoperative use of IV dexmedetomidine is strongly recommended as it reduces pain scores and opioid demand 1
- For video-assisted thoracoscopic surgery (VATS), regional analgesic techniques such as paravertebral block or erector spinae plane block should be incorporated as part of multimodal analgesia 1
For Bariatric Surgery:
- Anesthesia induction should be based on lean body weight to avoid hypotension, while maintenance infusion may be more appropriate based on total body weight 1
- Multimodal analgesia using limited doses of opioids is advocated due to increased sensitivity to opioid sedative effects in patients with obesity 1
For Cardiac Surgery:
- Enhanced recovery programs using short-acting anesthetic agents have been shown to prevent early postoperative complications and reduce time to extubation 1
- Volatile anesthetics may facilitate earlier extubation compared to intravenous anesthesia, though this doesn't impact mortality 1
Common Pitfalls and Caveats
- Avoid excessive depth of anesthesia, particularly in elderly patients, as this can increase the risk of postoperative confusion 1
- Be cautious with dexmedetomidine in patients with severe cardiac disease, conduction disorders, or rhythm disorders due to potential bradycardia and hypotension 1
- When using propofol for maintenance, infusion rates should be decreased by 30-50% during the first half-hour of maintenance after the induction dose 4
- For pediatric patients, maintenance infusion rates of propofol typically need to be higher (200-300 mcg/kg/min initially, then 125-150 mcg/kg/min after the first half-hour) 4
- When using dexmedetomidine with propofol, be aware that this combination may cause significant increases in blood pressure compared to dexmedetomidine with sevoflurane 8