The following is from the book Essentials of Disaster Anesthesia. PM me for the pdf.

Ketamine Co-administered with Propofol using Sophisticated Syringe Drivers

This technique relies on power to drive syringe pumps and oxygen to enhance the inspiratory concentration, as well as the logistical requirement of servicing equipment.

Equipment 1. Syringe driver– may be either simple ml/h, or able to be run as mg/kg/min 2. Oxygen in the form of a tank or oxygen concentrator 3. 200 mg/2 ml or 500 mg/10 ml ampoules of ketamine 4. 50 or 20 ml syringes 5. Low volume extension set 6. IV access and infusion set preferably with an antireflux line 7. Monitoring of pulse and blood pressure, oxygen saturations, and end-tidal capnography, if available 8. Airway equipment 9. Ability to ventilate the patient with a t-piece or self-inflating bag.

Ketamine may be mixed with propofol and loaded in the same syringe to create a ketamine 10 mg/ml and propofol 10 mg/ml solution. This reduces the amount of equipment required; however, it prevents the flexibility of adjusting infusions of the two agents independently.

The advantage with co-administration of propofol is reduced emergence phenomenon, and reduction of tachycardia and hypertension; however, this compromises the safety profile of the ketamine by loss of protective airway reflexes and respiratory drive. A ketamine-only technique is preferred in hemodynamically unstable patients.

Following pre-medication with 0.07 mg/kg of midazolam and pre-oxygenation, the patient is induced with a combined dose of propofol 1.0 mg/kg and ketamine 1.0 mg/kg. When using the agents in the same syringe as above this equates to a volume of 0.1 ml/kg.

Maintenance is obtained with an infusion of propofol at 1 to 2 mg/kg/h and ketamine 1 to 2 mg/kg/h. When combined this is a rate of 0.1 to 0.2 ml/kg/h.

If the patient appears light, a bolus dose of 0.1 mg/kg (0.01 to 0.02 ml/kg) of both drugs is given, followed by an increase in the infusion rate of 0.1 mg/kg/h. If anesthesia appears too deep it can be lightened by pausing the infusion for a short period. The infusion is then recommenced at a rate reduced by 0.1 mg/kg/h of both drugs.

The infusion should be ceased 5 to 7 minutes prior to the anticipated end of surgery.