Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order “to get everything done at one time.” A review of Sam’s health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that