What is the recommended propofol (2,6-diisopropylphenol) infusion regimen for neurosurgical procedures?

Propofol Infusion for Neurosurgery

For neurosurgical procedures, use a continuous propofol infusion at 50-100 mcg/kg/min for maintenance anesthesia, combined with short-acting opioids (fentanyl, alfentanil, sufentanil, or remifentanil) for analgesia during painful portions of surgery. 1

Induction Protocol

Administer propofol as a slow infusion of approximately 20 mg every 10 seconds until induction onset (1-2 mg/kg total), rather than rapid bolus injection. 2 This slower technique is critical in neurosurgical patients to avoid significant hypotension and decreases in cerebral perfusion pressure 2.

• The onset of action occurs within 30-45 seconds (arm-brain circulation time) 3, 4
• Slower induction titrated to clinical response generally results in reduced total induction dosage requirements of 1-2 mg/kg 2
• Never use rapid bolus administration in neurosurgical patients, as this increases the likelihood of undesirable cardiorespiratory depression including hypotension, apnea, airway obstruction, and oxygen desaturation 2

Maintenance Infusion Regimen

Maintain anesthesia with propofol at 50-100 mcg/kg/min as a continuous infusion. 1 This represents the standard maintenance regimen specifically recommended for neurosurgical procedures 1.

• Higher initial infusion rates of 150-200 mcg/kg/min may be required during the first 10-15 minutes following induction 2
• Subsequently decrease infusion rates by 30-50% during the first half-hour of maintenance 2
• Titrate to achieve rates of 50-100 mcg/kg/min to optimize recovery times 2

Adjunctive Analgesia

Combine propofol with short-acting opioids (fentanyl, alfentanil, sufentanil, or remifentanil) for analgesia during painful portions of surgery. 1 Propofol has minimal analgesic properties and requires opioid supplementation for adequate pain control 3.

• Administer fentanyl 50-75 mcg or equivalent opioid prior to propofol induction 3
• Combined therapy with opioids allows lower propofol doses, reducing cumulative dose and minimizing cardiorespiratory depression 3
• Consider adding midazolam 0.5-1.0 mg for enhanced amnesia, as propofol alone provides less reliable amnesia at lighter sedation levels 3, 4

Critical Hemodynamic Management

Have vasopressors immediately available (ephedrine or metaraminol) to treat hypotension. 1 Propofol causes dose-dependent decreases in blood pressure and cardiac output through decreased peripheral vascular resistance 3, 1.

• When increased intracranial pressure (ICP) is suspected, hyperventilation and hypocarbia should accompany propofol administration 2
• In patients where additional fluid therapy is contraindicated, consider elevation of lower extremities or pressor agents to offset hypotension 2
• Propofol decreases cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), and ICP, making it favorable for neurosurgery 5, 6

Monitoring Requirements

Use processed EEG monitoring (BIS 40-60) to prevent awareness and avoid excessive depth of anesthesia. 1 This is particularly important in neurosurgical patients where rapid emergence is needed for neurological assessment.

• Continuous pulse oximetry is necessary for early detection of respiratory depression 3
• Continuous blood pressure monitoring is required due to dose-dependent cardiovascular effects 3
• ECG monitoring is particularly important in patients with cardiovascular disease 3
• Consider capnography for early detection of hypoventilation 3

Cerebrovascular Effects

Propofol offers distinct advantages for neurosurgery compared to volatile anesthetics, which increase CBF, cerebral blood volume, and ICP in a dose-related manner 5.

• Propofol decreases CMRO2 and acts as a cerebral vasoconstrictor, making it rational for neurosurgical anesthesia 5
• Cerebral autoregulation and CO2 responsiveness are minimally affected by propofol 5
• Brain relaxation is encouraged through decreased CMRO2 and CBF 5

Common Pitfalls and Safety Considerations

Propofol causes dose-dependent respiratory depression and potential apnea. 4 Have bag-valve-mask ventilation immediately available 3.

• In pediatric studies, 8-11.6% of patients experienced oxygen saturation below 90-93% 3
• Transient hypotension is common but rarely requires intervention in healthy patients 3
• Never administer propofol with sodium nitroprusside through the same Y-site due to severe additive hypotensive effects 3
• Use separate dedicated IV lines if both medications are required 3

Special Populations and Contraindications

• Avoid propofol in patients with egg, soy, or sulfite allergies (formulation contains 10% soybean oil and 1.2% egg phosphatide) 3, 4
• Propofol is not contraindicated in sulfonamide allergy 3, 4
• Cirrhosis or renal insufficiency do not significantly affect propofol pharmacokinetics 3, 4

Recovery Profile

Propofol is associated with rapid and predictable recovery in the operating theater, allowing early neurological evaluation of the surgery 5, 7.

• Recovery is quicker compared to traditional anesthetic regimens 7
• The effect duration is 4-8 minutes after a single dose, with a terminal half-life of 1-3 days after prolonged infusion 4
• Abrupt discontinuation may result in rapid awakening with anxiety, agitation, and resistance to mechanical ventilation 2