Summary

In study session I you have learnt

• Blood pressure means the force exerted by the blood against any unit area of the vessel wall. Two pressures are recorded when measuring blood pressure, systolic pressure is the peak arterial BP attained during ventricular systole, and diastolic pressure is the minimum arterial BP between heartbeats at which the heart get its own blood supply.
• Blood pressure is determined mainly by cardiac output, blood volume, and peripheral resistance.
• Mean arterial blood pressure, a perfusing pressure to the tissue, is the product of cardiac output peripheral resistance
• Blood pressure is regulated by the baroreceptors located in the carotid sinus and aortic arch.
• Catecholamines (epinephrine and norepinephrine) are released from the adrenal medulla of the adrenal glands.
• In general any pathophysiologic alterations on the factors which regulate blood pressure; blood volume, peripheral resistance and cardiac output will alter the normal blood pressure.
• Hypertension is defined by 2 or more measurements of blood pressure greater than 140/90 mmHg. The degree of end-organ damage and morbidity and mortality correlate with the duration and severity of hypertension (HTN).
• The final common pathway in the pathophysiology of essential hypertension may be salt and water retention. With a stiffening (Vasoconstriction) of the arterial vasculature in chronic hypertension intravascular fluid volume will decrease.
• Decreasing blood pressure by lifestyle modification and pharmacologic therapy is intended to decrease morbidity and mortality. The standard goal of therapy is to decrease systemic blood pressure to lower than 140/90 mm Hg.
• A large variety of antihypertensive drugs are available, and many of these drugs present unique and potentially significant advantages and side effects.
• A hypertensive patient will benefited if he/she is managed by physician anesthesiologist or if not by experienced anesthetist and resource full hospital to prevent intraoperative complications which cause permanent disability and death.
• Preoperative evaluation of patients with essential hypertension begins with a determination of the adequacy of systemic blood pressure control and a review of the pharmacology of the antihypertensive drugs being used for therapy.
• Hypertension should be treated preoperatively because the incidence of hypotension and evidence of myocardial ischemia on the ECG during the maintenance of anesthesia is increased in a patient who is not treated.
• Being hypertensive before the induction of anesthesia. Perioperative therapy with β
• Sodium thiopental, propofol, midazolam, opioids (fentanyl), and etomidate all have been used to induce anesthesia. Ketamine is not selected for induction of anesthesia in patients with essential hypertension because it can increase systemic blood pressure and cause tachycardia, which may lead to myocardial ischemia.
• Hypoxia, tachycardia, hypotension, hypertension, and myocardial ischemia must be avoided. Yet, an excessive concentration or dose of anesthetic drugs can produce hypotension, which is as undesirable as hypertension.
• If hypotension occurs during maintenance of anesthesia it is often treated by decreasing the concentrations of volatile anesthetic while infusing fluids intravenously to increase intravascular fluid volume.
• Hypertension in the early postoperative period is a frequent occurrence in patients with a preoperative diagnosis of essential hypertension.