Review Author: Jake Darbhanga, DO
Figuring out when to start vasopressors in the ER setting can be a confusing situation with numerous options for the clinician to choose from regarding which pressors to use. The purpose of this article is to simplify when to start a pressor based on specific situations and which ones to consider.
Sepsis/ Septic Shock
o If the patient has received adequate fluids (30 mL/kg) and is still inadequately perfused (hypotensive, map <65, lactate >2 mmol/L, AMS, low urine output) start pressor sooner rather than later.
o Start Norepinephrine (Levophed) at 0.05mcg/kg/min
§ A-1 agonist (vasoconstrict) with minor B-1 agonism (increases heart rate and contractility)
o Epinephrine at 0.01-0.05 mcg/kg/min
§ May be used when norepinephrine is not enough and inotropic support is needed
o Vasopressin at rate of 0.01-0.04 units/min
§ Use as adjunct to norepinephrine
o Titrate as needed to a MAP of greater than equal to 65
Hypovolemic shock
o If low urine output, tachycardia, or AMS in addition to hypotension despite fluid administration.
o Norepinephrine (Levophed) at rate of 0.01 mcg/kg/min- 0.05 mcg/kg/min.
§ Increase by small increments (0.01mcg/kg/min) if inadequate
§ max dose up to 0.5 mcg/kg/min but this is in severe shock.
o Titrate as needed to MAP greater than equal to 65
Cardiogenic shock
o Setting of cardiac dysfunction and hypotensive patient with poor perfusion signs (cool extremities, low urine output). After giving fluids may need pressors.
o If hypotensive with low cardiac output may give Norepinephrine (Levophed) at rate of 0.01- 0.03 mcg/kg/min and aim for MAP greater than equal to 65 and adequate organ perfusion.
§ Max dose up to 0.5 mcg/kg/min. Doses greater than 0.2 mcg/kg/min are used in severe cases
o Use Dobutamine if low cardiac output in setting of preserved systemic vascular resistance. Dose is 2-5 mcg/kg/min and titrate as needed
o May combine Dobutamine with norepinephrine if hypotensive with low cardiac output
§ Dobutamine has inotropic properties
§ Norepinephrine has vasoconstrictive properties and mild inotropic effects
· May increase afterload which can improve coronary perfusion
o Milrinone at rate of 0.125-0.5 mcg/kg/min used if dobutamine is not enough or if patient has pulmonary hypertension.
Neurogenic shock
o Generally characterized by bradycardia and hypotension commonly due to loss of sympathetic tone due to spinal cord injury or autonomic failure. Due to this, generally see significant vasodilation. When adequate fluid resuscitation failed need pressors.
o Norepinephrine (Levophed) 0.01-0.1 mcg/kg/min and titrate at increments of 0.01-0.02 mcg/kg/min based on MAP
o May use/add Epinephrine 0.01-0.05 mcg/kg/min and titrate at increments of 0.01-0.05 mcg/kg/min to Norepinephrine
§ Max dose of 0.1-0.3 mcg/kg/min
§ This medication may be used when norepinephrine is not enough or in the setting of severe bradycardia. Will cause vasoconstriction and has inotropic and chronotropic effect
o Phenylephrine 0.1-0.5 mcg/kg/min and titrate at increments of 0.05-0.1 mcg/kg/min
§ Max dose of 1-2 mcg/kg/min
§ This medication is a pure A1 agonist, thus increasing blood pressure purely through vasoconstriction without increasing heart rate.
§ Useful when tachycardia is not desired or used when there is isolated vasodilation without bradycardia.
o Vasopressin 0.01-0.04 units/min
§ Max dose 0.04 units/min
§ Used if shock is refractory to Norepinephrine or Epinephrine. Promotes vasoconstriction
o Want MAP greater than equal to 65
Anaphylactic shock
o Anaphylaxis in addition to hypotension and shock. Generally IM Epinephrine is given but if hypotension is refractory to fluid resuscitation and IM epinephrine then start
o IM dose: Epinephrine 0.3-0.5 mg (1:1000 concentration, 1mg/mL) in adults and in kids 0.01 mg/kg (max of 0.3 mg/dose) IM
o IV dose: Epinephrine 0.1-0.5 mcg/kg/min with max dose of 0.1-0.3 mcg/kg/min
§ Epinephrine is desirable due to reversal of bronchospasm, vasodilation, and increased vascular permeability.
o Norepinephrine (Levophed)- 0.01-0.1 mcg/kg/min and titrate by increments of 0.01-0.02 mcg/kg/min.
§ Max dose of 1-2
o Want MAP greater than equal to 65
Risks associated with pressors are as follows:
· Tissue Ischemia is a rare but possible risk specifically with Norepinephrine and Phenylephrine
· Be cautious giving vasopressin peripherally as there is no vasodilatory medication to counter its actions if it extravasates
· Monitor kidney function when on pressors for long time as blood may be shunted from the kidneys to perfuse other vital organs
· Don’t give pressors for longer than 24-48 hours peripherally
References:
· Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021 (Intensive Care Medicine, 2021).
· Singer M, et al., The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3), JAMA, 2016.