1. Definition Hypertensive emergencies and subacute hypertension were once referred to as hypertensive crisis. Hypertensive emergencies, referring to patients with primary or secondary hypertension, have a sudden and significant increase in blood pressure (generally more than 180/12O mm Hg) under the action of certain triggers, accompanied by progressive cardiac, cerebral, renal and other important target organ insufficiency, including hypertensive encephalopathy, intracranial hemorrhage (cerebral hemorrhage and subarachnoid hemorrhage), cerebral infarction, acute heart failure, pulmonary edema, acute coronary syndrome (unstable angina pectoris, acute non-ST-segment elevation and ST-segment elevation myocardial infarction), aortic coarctation aneurysm, and eclampsia. The level of blood pressure is not directly proportional to the degree of acute target organ damage. Pregnancy or certain patients with acute glomerulonephritis are not associated with particularly high blood pressure values, but if blood pressure is not controlled in a reasonable range in a timely manner, it can have serious effects on organ function and even endanger life, and the management process requires great attention. Patients with acute pulmonary edema, aortic coarctation aneurysm, or myocardial infarction are considered hypertensive emergencies even if their blood pressure is only moderately elevated. Sub-acute hypertension: This refers to a significant increase in blood pressure without target organ damage. Patients may have symptoms caused by significantly elevated blood pressure, such as headache, chest tightness, nosebleeds, and irritability. A significant majority of patients with hypertensive emergencies and subacute hypertension have poor compliance with medication or are undertreated. The degree of elevated blood pressure is not a criterion to distinguish acute hypertension from subacute hypertension. The only criterion to distinguish the two is the presence of new acute progressive and severe target organ damage. 2. Management of hypertensive emergencies When hypertensive emergencies are suspected, relevant history collection, physical examination and laboratory tests are performed to evaluate the functional involvement of target organs in order to clarify whether it is a hypertensive emergency as soon as possible. The overall evaluation of the patient should not delay the initial treatment of hypertensive emergencies. Patients with hypertensive emergencies should remain in the emergency resuscitation unit or intensive care unit with continuous blood pressure monitoring; apply appropriate antihypertensive drugs as soon as possible; use effective sedatives as appropriate to eliminate patient fears; and treat different target organ damage accordingly. Hypertensive emergencies require immediate antihypertensive treatment to stop further damage to target organs. The type of medication, route of administration, rate of blood pressure reduction and target blood pressure level should be clarified before treatment. The pharmacological and pharmacokinetic effects of the drug need to be considered, with attention to the hemodynamic effects of cardiac output, systemic vascular resistance and target organ perfusion, as well as possible adverse effects. The ideal drug should be able to anticipate the intensity and speed of blood pressure lowering, and the intensity of action can be readily adjusted.