What are the recommended Total Intravenous Anesthesia (TIVA) propofol and fentanyl infusion rates in ml/hr for a 62-year-old female patient with an incomplete spinal cord injury and hypertension?

TIVA Propofol and Fentanyl Infusion Rates for 62-Year-Old Female with Incomplete Spinal Cord Injury and Hypertension

Critical Safety Considerations for This Patient

Given this patient's incomplete spinal cord injury and hypertension, you must be prepared for autonomic hyperreflexia (AH) during the procedure, which can cause sudden severe hypertension and bradycardia. 1 Have nicardipine 1-2 mg IV boluses ready, with continuous infusion capability at 2 mcg/kg/min if AH develops. 1

For this 62-year-old patient with hypertension, use reduced induction doses (approximately 80% of standard adult dosing) and slower administration rates to minimize cardiovascular depression. 2

Propofol Infusion Rates (ml/hr)

Induction Phase

• Administer propofol as a slow infusion at 100-150 mcg/kg/min for 3-5 minutes rather than rapid bolus to minimize hypotension in this elderly hypertensive patient. 2
• For a 62-year-old female (assuming 60 kg): This equals 360-540 mg/hr or 36-54 ml/hr using 1% propofol (10 mg/ml) for the initial 3-5 minutes. 2
• Reduce this calculated dose by approximately 20% due to age and hypertension: Use 30-45 ml/hr for induction. 2

Maintenance Phase

• Immediately following induction, start at 150-200 mcg/kg/min (higher rates) for the first 10-15 minutes. 2
• For 60 kg patient: 54-72 ml/hr for first 10-15 minutes. 2
• After the first 30 minutes, decrease infusion rate by 30-50% to 50-100 mcg/kg/min. 2
• For 60 kg patient: 18-36 ml/hr for maintenance after first 30 minutes. 2

Fentanyl Infusion Rates (ml/hr)

Initial Bolus

• Administer fentanyl 3-5 mcg/kg as initial bolus for intubation (if required), but use lower end (3 mcg/kg) in this hemodynamically unstable patient with hypertension. 3
• For 60 kg patient: 180-300 mcg total bolus (lower end preferred). 3
• Administer slowly over 2-3 minutes to avoid chest wall rigidity. 3, 4

Continuous Infusion

• Start fentanyl infusion at 0.02 mcg/kg/min during the operation. 5
• For 60 kg patient: 1.2 mcg/min = 72 mcg/hr. 5
• Using fentanyl 50 mcg/ml concentration: 1.4 ml/hr. 5

Alternative Dosing Strategy

• Administer fentanyl 1 mcg/kg bolus before surgical start, then continuous infusion at 0.02 mcg/kg/min. 5
• This method reduces total propofol and fentanyl requirements while maintaining stable hemodynamics. 5

Practical Syringe Pump Setup

Propofol (1% = 10 mg/ml)

• Induction: 30-45 ml/hr for 3-5 minutes 2
• Early maintenance (0-15 min): 54-72 ml/hr 2
• Late maintenance (>30 min): 18-36 ml/hr 2

Fentanyl (50 mcg/ml standard concentration)

• Initial bolus: 3.6-6 ml over 2-3 minutes (180-300 mcg for 60 kg) 3, 4
• Continuous infusion: 1.4 ml/hr (72 mcg/hr) 5

Hemodynamic Targets and Monitoring

Maintain systolic blood pressure >110 mmHg and <185 mmHg in this patient with spinal cord injury and hypertension. 3

• Have vasopressors (ephedrine or metaraminol) immediately available to treat propofol-induced hypotension. 3
• Monitor for autonomic hyperreflexia: sudden severe hypertension (>220/120 mmHg) with bradycardia during surgical manipulation below injury level. 1
• Continuous pulse oximetry and capnography are mandatory to detect respiratory depression early. 6
• Direct arterial pressure monitoring is strongly recommended in this high-risk patient with spinal cord injury and hypertension. 3

Dose Adjustment Algorithm

If blood pressure drops below 110 mmHg systolic:

• Decrease propofol infusion rate by 25-50% 2
• Administer vasopressor bolus (ephedrine 5-10 mg or metaraminol 0.5-1 mg) 3

If patient shows signs of light anesthesia (movement, tachycardia, hypertension):

• Increase propofol rate by 25-50 mcg/kg/min 2
• Consider fentanyl bolus of 25-50 mcg 3

If autonomic hyperreflexia develops (BP >220/120 mmHg with bradycardia):

• Administer nicardipine 1 mg IV bolus 1
• Start nicardipine infusion at 2 mcg/kg/min 1
• Deepen anesthesia with additional propofol and fentanyl 1

Critical Pitfalls to Avoid

• Never use rapid bolus administration in this elderly hypertensive patient—this will cause severe hypotension, apnea, and oxygen desaturation. 2
• Do not administer fentanyl rapidly—even 1 mcg/kg can cause chest wall rigidity if given as rapid bolus. 3, 4
• Avoid propofol doses <1.5 mg/kg for induction in elderly patients—paradoxically, underdosing can cause hypertension and tachycardia. 7
• Be vigilant for autonomic hyperreflexia during any surgical manipulation below the level of spinal cord injury. 1
• Have naloxone 0.1 mg/kg immediately available for reversal of respiratory depression. 4