Shock is a life-threatening condition which can cause multiple organ failure and even death. One characteristic of shock is low blood pressure which is managed with drugs called vasopressors. Most frequently used vasopressors are noradrenaline, vasopressin and recently also angiotensin II. Angiotensin II is present in the body and has a physiological role in maintaining blood pressure in healthy persons. Renin is an enzyme and a key factor in angiotensin II production in the body. In patients with shock, there is a lack of angiotensin II and an excess of renin in the body. Due to the literature renin has the potential to be a marker of severity of shock. Synthetic angiotensin II is used in patients with shock in whom we cannot normalize the blood pressure with noradrenaline and vasopressin. Regarding scientific data, the use of synthetic angiotensin II reduces the dose of noradrenaline and vasopressin and the incidence of acute kidney injury. The aim of our study is to find out what is the relation between the concentration of renin before and 6 hours after the start of using angiotensin II in patients with shock and their clinical outcome. Since not all patients with shock are responding to angiotensin II, the aim of our study is also to find out which patients could benefit most from synthetic angiotensin II.