What is the recommended propofol infusion dosage for sedation in a 90 kg adult patient?

Propofol Infusion Dosage for Sedation in a 90 kg Adult Patient

For ICU sedation in a 90 kg adult, start propofol at 5 μg/kg/min (0.3 mg/kg/h = 27 mg/h) without a loading dose if hemodynamically unstable, and titrate up to a maintenance range of 5-50 μg/kg/min (27-270 mg/h for 90 kg) to achieve light sedation (Ramsay Sedation Scale 2-3). 1, 2

Initial Dosing Strategy

Avoid bolus loading doses in hemodynamically unstable patients due to the high risk of hypotension from propofol's systemic vasodilation effects. 1, 2, 3 If a loading dose is absolutely necessary and the patient is hemodynamically stable, use 5 μg/kg/min over 5 minutes (approximately 27 mg total for 90 kg patient). 1, 3

For this 90 kg patient:

• Starting infusion rate: 27 mg/h (0.3 mg/kg/h or 5 μg/kg/min) 2
• Target maintenance range: 27-270 mg/h (0.3-3 mg/kg/h or 5-50 μg/kg/min) 1, 2
• Allow 3-5 minutes between dose adjustments to assess clinical effects 3

Titration to Target Sedation Level

Target light sedation (patient arousable and able to follow simple commands) rather than deep sedation to minimize complications including prolonged mechanical ventilation, delirium, and ICU length of stay. 1, 2 This corresponds to a Ramsay Sedation Scale of 2-3. 4

• Typical effective dose for light sedation: 0.71 mg/kg/h (approximately 64 mg/h for 90 kg) with plasma concentrations of 0.58 μg/ml 4
• Optimize recovery by maintaining rates of 50-100 μg/kg/min (270-540 mg/h for 90 kg) during maintenance 1, 3
• Titrate downward in absence of clinical signs of light anesthesia to avoid unnecessarily high rates 3

Critical Safety Monitoring

Propofol Infusion Syndrome (PRIS)

Monitor vigilantly for PRIS, especially with doses >70 μg/kg/min (>378 mg/h for 90 kg) or infusions lasting >48 hours. 1, 2, 5 However, PRIS has been reported at doses as low as 1.9-2.6 mg/kg/h (171-234 mg/h for 90 kg). 2, 5

Early warning signs requiring immediate propofol discontinuation: 1, 2

• Worsening metabolic acidosis (unexplained)
• Hypertriglyceridemia
• Hypotension with increasing vasopressor requirements
• New arrhythmias (bradycardia, atrial fibrillation, bundle branch block)
• Acute kidney injury or hyperkalemia
• Rhabdomyolysis (elevated creatine kinase, myoglobinuria)

PRIS carries up to 33% mortality even after discontinuing the infusion, making early recognition critical. 1, 2

Cardiovascular and Respiratory Effects

• Expect dose-dependent hypotension from systemic vasodilation without compensatory tachycardia 1, 6
• Monitor for respiratory depression requiring mechanical ventilation support 1, 6
• 5-7% of patients may experience transient oxygen desaturation below 90% 2
• Cardiopulmonary depression is more pronounced when combined with opioids 1

Special Considerations for This Patient

Nutritional Accounting

Propofol provides 1.1 kcal/ml from its 10% lipid emulsion. 2 At 64 mg/h (6.4 ml/h), this contributes approximately 169 kcal/day. For higher infusion rates of 270 mg/h (27 ml/h), this increases to 712 kcal/day. Adjust nutritional requirements accordingly to prevent overfeeding. 2

Analgesic Supplementation

Propofol has no analgesic properties—combine with short-acting opioids (e.g., fentanyl, remifentanil) for painful procedures or conditions. 1, 6 The combination potentiates sedative effects, allowing lower propofol doses. 6, 3

Allergy Screening

Avoid propofol in patients with egg or soybean allergies due to its formulation in 10% lipid emulsion containing egg lecithin and soybean oil. 1, 6 Some generic formulations contain sulfite preservatives. 1

Advantages for ICU Sedation

• Rapid onset (1-2 minutes) and short elimination half-life (3-12 hours with short-term use) allow precise titration and facilitate daily sedation interruption protocols 1, 2
• Useful for patients requiring frequent neurologic assessments due to rapid offset after short-term administration 1, 2
• Shorter recovery time compared to benzodiazepines 2

Common Pitfalls to Avoid

• Never administer loading doses in hemodynamically unstable patients 2, 3
• Do not use doses >70 μg/kg/min (>378 mg/h for 90 kg) without heightened PRIS surveillance 2, 5
• Avoid rapid bolus administration in elderly or ASA-PS III/IV patients (use 20 mg every 10 seconds if needed) 3
• Do not forget to account for propofol's caloric contribution when calculating total nutritional needs 2
• Long-term administration (>48 hours) can lead to peripheral tissue saturation and prolonged emergence 1