A. Initial Bolus: 1.5 2.5 mg/kg.
B. Give in 2 3 divided doses.
C. Patient will be apneic within 30 90 seconds.
III. Total Intravenous Anesthesia (propofol/ketamine):
200-400 µg 2-3 min prior to induction
No initial bolus
Start at 1 mg/min
At 1 hour: .6 mg/min
At 4 hours: .4 mg/min
Turn off ketamine infusion
15 30 minutes prior to the
end of surgery.
Initial Bolus: 0.8 1.2 mg/kg
(1 2 minutes after fentanyl)
Start at 140-200 µg/kg/min
At 10 minutes: 100 140 µg/kg/min
After 2 hours: 80-120 µg/kg/min
Turn off propofol infusion
about 5-10 minutes prior to the
desired time of emergence. Give 1-2 cc boluses as needed to keep patient asleep until the desired time of emergence.
A. Even small boluses (1 2 cc) may cause apnea, especially following a premed.
B. Reduce propofol doses by 40 60% for elderly patients, sick patients, or following a heavy premed.
A. Check repeatedly that the infusion is running. Continuous infusions are prone to equipment problems, such as the clamps left on the line, running out of drug, excessive backpressure in the line, etc. If the infusion stops for more than a few minutes, your patient will awaken during the operation.
B. Propofol is not amnestic, so patients must be kept completely unconsciousness with propofol to prevent intraoperative awareness.
C. Infuse the propofol through a t-piece connected immediately proximal to the IV catheter to minimize dead space.
D. If the infusion rate is not turned down over time the patient will be overdosed.
E. The infusion can be titrated to blood pressure and heart rate.
F. If your patient is too deep, turn off the propofol for a minute or two. (Remember to turn it back on, or your patient will wake up!) If your patient is too light, give a 1 4 cc bolus of propofol, and increase the infusion rate.
G. The infusion rates are intended for adults in the normal weight range (60-80 kg). The infusion rates should be increased for larger patients and decreased for smaller patients.
H. For sedation, start with an infusion only (no bolus) and titrate to level of wakefulness, respiratory rate, etc.
I. Don't turn off the infusion until 5-10 minutes before the operation is finished.
J. Once the infusion is off, be prepared to give 1-2 cc boluses of propofol for signs of light anesthesia. This allows assessment of anesthetic depth, and thus facilitates rapid emergence at the end of surgery.
A. Anticipate that the blood pressure will drop following the propofol/fentanyl induction. It usually returns promptly with intubation.
B. Reduce the doses 25 50% for elderly, sick, or heavily premedicated patients.
C. TIVA means no N2O and no isoflurane.
D. Titrate the propofol infusion rate, not the ketamine infusion rate. If the patient seems to require a lot of propofol, give 25-50 µg fentanyl boluses.
F. As with propofol, the ketamine infusion rate was designed for adults of average weight (60-80 kg). Adjust upward or downward for larger or smaller patients.
G. Movement is a good sign of light anesthesia, so complete paralysis should be avoided if possible.
H. Watch the pupils for signs of opioid overdose. If the pupils become pinpoint, don't administer addition opioid.
K. TIVA with propofol/ketamine has not been associated with awareness. Propofol effectively blocks the psychotomimetic effects of ketamine.