Septic shock is defined as sepsis with persistent hypotension requiring vasopressors to maintain mean arterial pressure (MAP)≥ 65 mmHg and a serum lactate level of > 2 mmol/L (18 mg/dL) despite sufficient volume resuscitation . Hypovolemia (both relative and absolute) and reduced vascular tone have a role in determining the severity of hypotension in septic shock~. When mean arterial pressure (MAP) falls below a specific critical level organ blood flow is physiologically dependent on perfusion pressure. Fluid resuscitation and vasopressors have an influence on hypovolemia and the vascular tone in the early phase, as fluid resuscitation aims to correct hypovolemia and vasopressors-norepinephrine (NE)- as a first-line drug aiming to restore vascular tone to assure organ perfusion~. Norepinephrine is both an alpha1- and beta1-agonist so it is able to increase vascular tone and contractility~. Nevertheless, a large amount of fluids will increase the risk of fluid overload, which is a common complication during septic shock resuscitation~After the early phase, only fifty percent of patients respond to fluid administration, meaning that fluid treatment cannot boost cardiac output (CO) The current data indicate that the time from the onset of septic shock to the initiation of norepinephrine administration is a significant survival predictor; however, a suggestion for the optimal time to provide norepinephrine support was not explicitly expressed
Septic shock is defined as sepsis with persistent hypotension requiring vasopressors to maintain mean arterial pressure (MAP)≥ 65 mmHg and a serum lactate level of > 2 mmol/L (18 mg/dL) despite sufficient volume resuscitation~. Hypovolemia (both relative and absolute) and reduced vascular tone have a role in determining the severity of hypotension in septic shock