What is the recommended infusion dose of noradrenaline (norepinephrine) for treating severe hypotension or septic shock?

Norepinephrine Infusion Dosing for Severe Hypotension and Septic Shock

The recommended initial infusion dose of norepinephrine for treating severe hypotension or septic shock is 0.1-0.5 mcg/kg/min (equivalent to 7-35 mcg/min in a 70 kg adult), which should be titrated to achieve a target mean arterial pressure (MAP) of at least 65 mmHg. 1, 2

Initial Dosing and Administration

• Norepinephrine is the first-choice vasopressor for septic shock due to its superior efficacy and safety profile compared to other agents 1, 2, 3
• Administration requires central venous access whenever possible to prevent tissue necrosis from extravasation 1, 3
• Arterial catheter placement is recommended for continuous blood pressure monitoring in all patients requiring vasopressors 2, 3
• At least 30 mL/kg of IV crystalloid fluid should be given within the first 3 hours before or alongside vasopressor therapy 3

Titration and Target Blood Pressure

• Titrate norepinephrine to achieve a target MAP of 65 mmHg in most patients 1, 2, 3
• In patients with chronic hypertension, consider a higher MAP target of 80-85 mmHg, as this may reduce the need for renal replacement therapy (though with increased risk of arrhythmias) 3
• Early administration of norepinephrine is beneficial as it can:
  • Prevent prolonged severe hypotension 4, 5
  • Increase cardiac output through improved cardiac preload and contractility 6, 5
  • Improve microcirculation and tissue oxygenation 5
  • Prevent fluid overload 4, 5

Management of Refractory Hypotension

• If target MAP cannot be achieved with maximum doses of norepinephrine, add vasopressin (up to 0.03 U/min) to either raise MAP or decrease norepinephrine dosage 1, 2, 3
• The recommended starting dose of vasopressin is 0.01-0.03 units/minute 3
• Vasopressin should not be used as the initial single vasopressor for septic shock 2, 3
• Epinephrine can be added as an alternative second agent when norepinephrine and vasopressin are insufficient 1, 3

Special Considerations and Pitfalls

• Norepinephrine is relatively contraindicated in patients with hypovolemia; ensure adequate fluid resuscitation before or during administration 1
• Norepinephrine may increase myocardial oxygen requirements, requiring cautious use in patients with ischemic heart disease 1
• If extravasation occurs, infiltrate 5-10 mg of phentolamine diluted in 10-15 mL of saline into the site as soon as possible to prevent tissue necrosis 1
• Higher norepinephrine doses (>0.38 mcg/kg/min) may predict a favorable microcirculatory response to vasopressin addition 7
• Dopamine should only be used as an alternative to norepinephrine in highly selected patients with low risk of tachyarrhythmias or with bradycardia 1, 3

Monitoring During Therapy

• Continuously monitor arterial blood pressure 2, 3
• Assess tissue perfusion through multiple parameters including blood lactate concentrations, skin perfusion, mental status, and urine output 1
• Consider measuring cardiac output when using pure vasopressors to ensure maintenance of adequate tissue perfusion 3