Toward an advisory system for cesarean section spinal anesthesia

Phenylephrine is a drug used at BC Women's Hospital, Vancouver BC to treat maternal hypotension induced by spinal anesthesia. Its dosage is mainly determined in a heuristic manner by the anesthetist's experience. Since an overdose of phenylephrine can result in bradycardia and hypertension, anesthesiologists are in need of a systematic method to calculate the correct dose. This problem is formulated in control engineering framework. An advisory system offers the optimal dosage of phenylephrine that ensures an appropriate blood pressure response, while rejecting disturbances created by the spinal anesthesia at the same time. The solution involves identifying the patient model. The advisory system is designed such that the model predictive controller recommends the adequate phenylephrine infusion, which has to be approved by the anesthesiologist in charge. The safety aspects related to the human subjects are dealt by constraints implemented within the advisory system. Upcoming clinical trials of the advisory system should confirm the value of this project in the near future.