Proper Order for Starting Vasopressors and Inotropes in Hypotension
Norepinephrine is the first-line vasopressor for fluid-refractory hypotension, followed by vasopressin (0.03 units/min) or epinephrine as second-line agents, with dobutamine added separately if cardiac output remains inadequate despite adequate blood pressure, and dopamine reserved only for highly selected patients with bradycardia or low risk of tachyarrhythmias. 1, 2
First-Line Agent: Norepinephrine
- Norepinephrine (0.2-1.0 μg/kg/min) is the recommended first-choice vasopressor for treating fluid-refractory hypotension in septic shock and most other shock states. 1, 2, 3
- This recommendation is based on superior efficacy and safety profile compared to dopamine, with lower risk of tachyarrhythmias and adverse events. 1, 4
- Norepinephrine should be initiated after adequate fluid resuscitation, targeting a mean arterial pressure (MAP) of 65 mmHg. 1, 2
- Central venous access is required for norepinephrine administration, and arterial catheter placement should be established as soon as practical for continuous blood pressure monitoring. 1, 2
Second-Line Agents: Vasopressin or Epinephrine
If target MAP is not achieved with norepinephrine alone, add one of the following:
- Vasopressin (0.03 units/min) can be added to norepinephrine to either raise MAP to target or decrease norepinephrine dosage requirements. 1, 2
- Vasopressin should NOT be used as a single initial vasopressor, and doses higher than 0.03-0.04 units/min should be reserved for salvage therapy only. 1, 2
- Epinephrine (0.05-0.5 μg/kg/min) can be added to or substituted for norepinephrine when an additional agent is needed to maintain adequate blood pressure. 1, 3
Inotropic Support: Dobutamine
- Dobutamine (2-20 μg/kg/min) should be added separately when there is evidence of persistent hypoperfusion or low cardiac output despite adequate fluid loading and achievement of adequate MAP with vasopressors. 1, 3
- Dobutamine is the first-choice inotrope for patients with measured or suspected low cardiac output in the presence of adequate left ventricular filling pressure. 1, 3
- This agent should be titrated to endpoints reflecting tissue perfusion and reduced or discontinued if worsening hypotension or arrhythmias develop. 1
Dopamine: Limited Role Only
- Dopamine should be used ONLY as an alternative to norepinephrine in highly selected patients with low risk of tachyarrhythmias and absolute or relative bradycardia. 1, 2
- At doses >5 μg/kg/min, dopamine provides vasopressor effects, but evidence suggests patients treated with dopamine may have worse outcomes than those treated with norepinephrine. 1
- Low-dose dopamine should NOT be used for renal protection—this practice is strongly discouraged. 1, 2
Critical Clinical Considerations
Timing matters: In patients with profound, life-threatening hypotension (diastolic BP ≤40 mmHg or diastolic shock index ≥3), early norepinephrine administration simultaneously with fluid resuscitation should be considered rather than waiting for complete fluid resuscitation. 5
Monitoring requirements: All patients requiring vasopressors should have arterial catheter placement for continuous blood pressure monitoring and ECG monitoring for arrhythmia detection. 1, 3
Common pitfall: Avoid using dopamine as first-line therapy—multiple guidelines now recommend norepinephrine first due to better outcomes and lower adverse event rates. 1, 2, 4
Age-specific consideration: In pediatric patients (<6 months), there may be age-specific insensitivity to dopamine due to incomplete sympathetic innervation, making norepinephrine a more reliable choice. 1
Salvage Therapy Options
For refractory shock not responding to the above sequence:
- Phenylephrine may be considered only when norepinephrine causes serious arrhythmias, cardiac output is known to be high with persistently low blood pressure, or as salvage therapy when other agents have failed. 1
- Angiotensin II is a newer option for profoundly hypotensive patients refractory to other vasopressors. 6