Preoperative and postoperative hypertension

Abstract

Introduction Hypertension affects an estimated 76 million persons in the USA, including one in three adults and more than 65% of individuals over age 65 years [1]. Thus, it is a very common disorder affecting many surgical patients. Hypertension often causes end-organ damage of the brain, heart, and kidneys, with important implications for surgical risk and perioperative management. Patients with chronic hypertension will often have perioperative episodes of hypertension that will require intervention. In addition, postoperative hypertension is common even without preexisting hypertension, especially in patients undergoing cardiac or carotid surgery. This chapter concentrates on the preoperative risk assessment and management of hypertensive patients and on the perioperative management of hypertension. Hemodynamic response to anesthesia A discussion of perioperative hypertension requires a basic understanding of the physiologic responses to anesthesia in normotensive and hypertensive patients. There are four main periods during anesthesia: induction, intubation, maintenance, and recovery periods. During induction, most patients' blood pressure falls. During laryngoscopy and intubation, the sympathetic nervous system is activated and blood pressure and heart rate rise. With deepening anesthesia, a decline in mean arterial pressure and heart rate occur due to the effects of pharmacologic agents, a decrease in sympathetic nervous system activity, and loss of the baroreceptor reflex. During recovery from anesthesia around the time of extubation, blood pressure and heart rate slowly increase in the first 15 minutes, and are accompanied by general arousal.