Blocks placed preoperatively are not time based charges, and consequently should not be be billed as procedure base unit plus time. If one wants to charge anesthesia time for the placement of these blocks, it would be best to administer the block in the actual OR. Even if sedation is provided, you should be monitoring the patient, and recording the monitoring to even consider billing for time. Additionally, unless the anesthesia provider remains in direct physical contact with the patient until they arrive in the OR, you will need to use 'discontinuous time' as a billing methodology. Too much work to be worthwhile, and not worth the loss of a compliance audit.