A 28-year-old woman presents for an elective cesarean section for a breech presentation of a full-term fetus. An uneventful spinal anesthetic is administered. Soon after delivery of the baby, she develops a sinus tachycardia (heart rate 110–130 beats per minute) and hypertension (blood pressure 150–170/90–105 mmHg). These hemodynamic abnormalities persist during her first 30 minutes in the postanesthesia care unit. Upon questioning, the patient admits to a prior history of frequent palpitations and feeling jittery. She also claims that her husband is “always turning the heat too high.” Her vital signs return to normal after treatment with a total dose of 25 mg of labetolol intravenously.