When to initiate noradrenaline (norepinephrine) in a patient with hypotension, who has received 1 liter of fluids over the last hour with a mediocre response and a mean arterial pressure (MAP) of 50?

From the Guidelines

Noradrenaline (norepinephrine) should be initiated immediately in this patient with persistent hypotension (MAP of 50) despite receiving 1 liter of fluid resuscitation over the last hour with only a mediocre response. The patient's condition suggests distributive or cardiogenic shock that is not adequately responding to fluid resuscitation alone, necessitating the use of vasopressors to maintain adequate blood pressure and perfusion of vital organs 1.

Key Considerations for Initiating Noradrenaline

• The target mean arterial pressure (MAP) should be at least 65 mmHg, as recommended by the Surviving Sepsis Campaign guidelines 1.
• Noradrenaline is the first-choice vasopressor due to its efficacy in increasing systemic vascular resistance and blood pressure, with modest beta-1 effects supporting cardiac output 1.
• The initial dose of noradrenaline should be 0.1-0.5 mcg/kg/min, titrated every 5-10 minutes to achieve the target MAP, typically not exceeding 1-2 mcg/kg/min 1.
• Continuous blood pressure monitoring is essential during administration, and consideration should be given to placing an arterial catheter if resources are available 1.

Fluid Resuscitation Considerations

• Fluid therapy should continue alongside vasopressor administration, with the goal of improving microvascular blood flow through increased cardiac output 1.
• Crystalloid solutions are the first choice for fluid resuscitation due to their tolerability and cost-effectiveness 1.
• The fluid challenge should aim to increase systemic arterial pressure while avoiding pulmonary edema through appropriate monitoring 1.

Ongoing Management

• While initiating vasopressors, it is crucial to continue addressing the underlying cause of shock and to monitor for signs of end-organ perfusion, including urine output, mental status, skin perfusion, and lactate levels 1.
• Additional fluid resuscitation should be considered if the patient remains fluid responsive, with careful monitoring to avoid fluid overload 1.

The management of this patient should be guided by the principles of early recognition of sepsis, prompt administration of intravenous fluids, and the appropriate use of vasopressors to maintain adequate blood pressure, as outlined in the Surviving Sepsis Campaign guidelines and other consensus recommendations 1.

From the Research

Indications for Noradrenaline in ED

• The decision to initiate noradrenaline in a patient with hypotension, who has received 1 liter of fluids over the last hour with a mediocre response and a mean arterial pressure (MAP) of 50, should be based on the patient's individual response to fluid resuscitation and the underlying cause of shock 2, 3.
• Noradrenaline is an appropriate choice as a first-line vasopressor for patients with shock, including cardiogenic or septic shock, titrated to achieve an adequate arterial pressure due to a lower risk of adverse events than other catecholamine vasopressors 2.
• The use of noradrenaline should take both arterial pressure and tissue perfusion into account when choosing therapeutic interventions 2.

Fluid Resuscitation

• Patients with hypotension should receive intravenous fluid resuscitation, with a goal of achieving adequate tissue perfusion 4, 3.
• The amount and rate of fluid administration should be tailored to the individual patient's response, with careful monitoring of hemodynamic parameters and tissue perfusion 4, 5.
• If the patient's response to fluid resuscitation is mediocre, and the MAP remains low, the use of vasopressors such as noradrenaline may be considered 4, 3.

Timing and Duration of Noradrenaline Therapy

• The optimal timing for initiating noradrenaline therapy in patients with hypotension is not well established, and further research is needed to determine the best approach 4.
• In one study, noradrenaline was initiated at 0.05 mcg/kg/min with a maximum of 0.15 mcg/kg/min through a peripheral venous catheter for up to 24 hours 4.
• The duration of noradrenaline therapy should be tailored to the individual patient's response, with careful monitoring of hemodynamic parameters and tissue perfusion 3, 5.