Special Operations Forces Medical Handbook

5-158

Example 2.
Continuous infusion of propofol and ketamine
Induction: Propofol (2 mg/kg) followed by ketamine 1 mg/kg and vecuronium 0.1 mg/kg.
Following intubation, initiate an infusion of propofol and ketamine. This combination requires two separate
infusion bags, as the propofol infusion is deliberately titrated downward more aggressively than the ket-
amine.
Infusion rates are as follows:
Ketamine (1.5 mg/kg/hr)
Propofol (12 mg/kg/hr) for the first 30 minutes, then (9 mg/kg/hr) for 30 minutes, lastly (6 mg/kg/hr).

Prepare the two infusions as follows:
Ketamine 150 mg in a 50 ml bag of 0.9% normal saline, yielding a concentration of 3 mg/ml. Infuse at the
rates mentioned above. Determine the infusion rate to deliver this concentration by using the formula:

Patient’s weight (kg) = ml to be infused per hour

2

Sample Calculations: For a patient weighing 80 kg

1. Ketamine infusion of 1.5 mg/kg/hr, means 1.5 mg x 80 kg or 120 mg/hr is required.


2. Using the formula:

Patient’s weight (kg) = ml to be infused per hour or 80/2 = 40 ml/hr to be infused for this patient
2

Therefore, 120 mg/hr required divided by 40 ml/hr (determined infusion rate) yields a 3 mg/ml concentration
required.

3. Adding 150 mg of ketamine to 50 ml of 0.9% normal saline yields a concentration of 3 mg/ml

Propofol can be mixed in a 50:50 solution using 0.9% normal saline. The resulting concentration (5 mg/ml)
allows for easy titration. To prepare the mixture, add 1000 mg of propofol to a 100 ml bag of 0.9% normal
saline. This results in 1000 mg in 200 ml and creates enough propofol for most procedures under one hour in
duration. With the 80 kg patient, the first 30 minutes would require approximately 100 ml of the solution:
12 mg/kg/hr X 80 kg = 960 mg/hr
960 mg/hr divided by 5 mg/ml (concentration) = 192 mg/hr
192 mg/hr divided by .5 (first 30 minutes) = 96 ml.

The second 30 minutes would required approximately 75 ml of the solution, with the subsequent infusion
rate being approximately 50 ml/hr. Discontinuing both infusions 15-20 minutes prior to the end of surgery
results in a smooth emergence.

Example 3.
Continuous infusion of propofol with incremental boluses of fentanyl

Induction: Propofol (2 mg/kg) followed by fentanyl 3 mcg/kg and vecuronium 0.1 mg/kg.
Following intubation, initiate an infusion of propofol at the following rates:

1. Propofol (12 mg/kg/hr) for the first 30 minutes, then (9 mg/kg/hr) for 30 minutes, then (6 mg/kg/hr)
   thereafter.


2. Propofol can be mixed in a 50:50 solution using 0.9% normal saline. The infusion technique is described
   in Example 2.


3. Administer fentanyl boluses of 0.25 mcg/kg as required, not to exceed 2 mcg/kg/hr. Toward the
   end of surgery, titrate fentanyl boluses to the patient’s respiratory effort.