Computer-controlled anesthetic delivery system

We designed and tested a computer-controlled syringe pump for the administration of volatile anesthetics into a closed breathing circuit. The system consists of a small computer, a flip-flop circuit, and an automatic syringe pump. The computer was programmed to administer liquid anesthetics according to the square root of time model of anesthetic uptake. A simple electronic flip-flop circuit connected the computer to the syringe pump. Safeguards to prevent accidental anesthetic overdosage and algorithms to provide for dosage changes based on patient response were written into the program. After testing, the system was used to administer anesthetics to ten patients undergoing surgical procedures. The anesthetic uptake deviated from the square root of time model after approximately two hours. The system provided smooth and reliable administration of volatile anesthetics during closed circuit anesthesia.