Vasopressor Selection in Shock States

First‑Line Vasopressor Recommendations

• The Surviving Sepsis Campaign recommends norepinephrine as the first‑choice vasopressor for septic shock and most forms of distributive shock after adequate fluid resuscitation (≥30 mL/kg crystalloid). Strong recommendation. 1
• For distributive shock of any etiology (e.g., sepsis, pancreatitis), norepinephrine is the preferred initial agent. Strong recommendation. 2

Indications for Norepinephrine

Advantages of Norepinephrine Over Dopamine

• In septic shock, norepinephrine reduces 28‑day mortality compared with dopamine (Risk Ratio 0.91; 95 % CI 0.83‑0.99). Moderate‑quality evidence. 4
• Norepinephrine is associated with fewer supraventricular (RR 0.47) and ventricular arrhythmias (RR 0.35) than dopamine. Moderate‑quality evidence. 4
• Despite theoretical concerns about renal vasoconstriction, norepinephrine improves renal blood flow and urine output in sepsis. Moderate‑quality evidence. 3

Epinephrine (Adrenaline) Use

• Epinephrine should be added (or substituted) when norepinephrine alone cannot maintain MAP ≥ 65 mmHg in septic shock, typically at norepinephrine‑equivalent doses of 37–133 µg/min. Strong recommendation. 1
• In refractory septic shock, the addition of epinephrine is advised after the above dose threshold is reached. Strong recommendation. 5
• Anaphylaxis: administer epinephrine 0.3–0.5 mg intramuscularly (adults ≥ 30 kg) or 0.01 mg/kg up to 0.3 mg (children < 30 kg) into the anterolateral thigh every 5–10 min. Strong recommendation. 3
• Cardiac arrest: give epinephrine 1 mg IV every 3–5 min during CPR; improves ROSC and short‑term survival, and for shockable rhythms it is given after the third shock. Strong recommendation. 6
• Symptomatic bradycardia unresponsive to atropine or pacing: epinephrine is an alternative. Strong recommendation. 3
• Resource‑limited settings: epinephrine may be used as an alternative to norepinephrine when the latter is unavailable, though dopamine is often preferred for cost and side‑effect considerations. Conditional recommendation. 7

Escalation Strategy in Septic Shock

• Step 1 – Initiate norepinephrine to reach MAP ≥ 65 mmHg after fluid resuscitation. Guideline 1
• Step 2 – Add epinephrine if MAP remains <65 mmHg while norepinephrine dose is 37–133 µg/min (equivalent). Guideline 1
• Alternative adjunct: add vasopressin 0.03 U/min to reduce norepinephrine requirements. Guideline 5

Special Population Considerations

• Bradycardia with hypotension – consider dopamine rather than norepinephrine. Guideline 1
• Known cardiac dysfunction – avoid epinephrine; use norepinephrine possibly combined with dobutamine. Guideline 2

Contra‑indications and Common Pitfalls

• Dopamine for renal protection – no demonstrated benefit; should not be used for this purpose. Guideline 1

All statements are derived from cited guideline and peer‑reviewed sources; strength of evidence is indicated where reported.

Management of Norepinephrine‑Refractory Shock

Recommended Vasopressor Strategies

Role of Dopamine

Norepinephrine Optimization

Monitoring Requirements

Contraindicated Practices

Vasopressor Selection and Management in Septic and Distributive Shock

First‑Line Vasopressor Recommendation

• The Surviving Sepsis Campaign strongly recommends norepinephrine as the first‑choice vasopressor for septic shock (moderate‑quality evidence)【14】【15】【16】.

Renal Effects of Vasopressors

• In sepsis, norepinephrine improves renal blood flow and urine output, counteracting the misconception that dopamine provides renal protection【14】【17】.

Dopamine Use – Indications and Contraindications

Indications (Rare, Selected Patients)

• Dopamine may be considered as an alternative first‑line agent only in patients with absolute or relative bradycardia (heart rate < 60–70 bpm) and hypotension【17】, or in patients at very low risk for tachyarrhythmias (no prior atrial fibrillation, no active myocardial ischemia)【14】. This is a weak recommendation based on low‑quality evidence【14】.

Contraindications

• Low‑dose dopamine (2–5 µg/kg/min) should never be used for renal protection; high‑quality evidence shows no benefit, yielding a strong recommendation【14】.
• Dopamine should be avoided in patients with a history of tachyarrhythmias or active myocardial ischemia because of a high risk of arrhythmogenic events【14】.

Dosing Guidelines

Norepinephrine

• Starting dose: 0.1–0.5 µg/kg/min (≈7–35 µg/min for a 70‑kg adult)【17】.
• Titrate to maintain mean arterial pressure (MAP) ≥ 65 mmHg.
• Maximum dose before adding a second‑line agent: ≈0.5 µg/kg/min (≈35 µg/min for a 70‑kg adult)【17】.

Dopamine (When Indicated)

• Starting dose: 5–10 µg/kg/min【17】.
• Titrate in increments of 5–10 µg/kg/min【17】.
• Usual therapeutic range: 5–20 µg/kg/min; doses >20 µg/kg/min require careful monitoring and are generally discouraged【17】.

Escalation Algorithm for Septic Shock

• Dopamine is not recommended as a second‑line agent in norepinephrine‑refractory shock.

Monitoring Requirements

• Placement of an arterial catheter is recommended (weak recommendation, very low‑quality evidence) to allow continuous blood pressure monitoring and rapid titration of vasopressors【14】.

Special Populations – Post‑Cardiac Arrest

• Norepinephrine: 0.1–0.5 µg/kg/min for severe hypotension (systolic BP < 70 mmHg) with low systemic vascular resistance【17】.
• Dopamine: 5–10 µg/kg/min may be considered when hypotension is accompanied by symptomatic bradycardia【17】.
• Epinephrine: Preferred for symptomatic bradycardia unresponsive to atropine or pacing【17】.

Guideline Recommendations for Vasopressor Use in Septic Shock

First‑Line Vasopressor (Norepinephrine)

• Norepinephrine is the recommended first‑choice vasopressor for septic and other distributive shock; escalation to a second‑line agent is advised when the infusion reaches 0.25–0.50 µg·kg⁻¹·min⁻¹. 18
• The therapeutic target is a mean arterial pressure (MAP) ≥ 65 mm Hg, achieved by titrating norepinephrine to the required dose. 18

Escalation Threshold to Second‑Line Agent

• When norepinephrine dose reaches 0.25–0.50 µg·kg⁻¹·min⁻¹ without attaining the MAP goal, a second‑line vasopressor should be added. 18

Second‑Line Vasopressor (Vasopressin)

• Add vasopressin at a fixed dose of 0.03 U·min⁻¹ (1.8 U·h⁻¹) once norepinephrine is in the 0.25–0.50 µg·kg⁻¹·min⁻¹ range and MAP < 65 mm Hg. 18

Vasopressin Dosing and Administration

• Recommended dose: 0.03 U·min⁻¹ as a non‑titrated infusion. 18
• Maximum allowable dose: up to 0.04 U·min⁻¹; doses >0.04 U·min⁻¹ are reserved for salvage therapy only. 18
• Vasopressin must be administered in addition to norepinephrine; it should never replace norepinephrine as the initial vasopressor. 18

Alternative Second‑Line Agent (Epinephrine)

• If vasopressin is unavailable or contraindicated, epinephrine may be added at 0.1–0.5 µg·kg⁻¹·min⁻¹. 18
• Epinephrine is associated with a higher incidence of lactate elevation and tachyarrhythmias compared with vasopressin. 19

Limited Role of Dopamine

• Dopamine is not recommended as a second‑line agent for norepinephrine‑refractory shock; its use is limited to selected patients as an alternative first‑line agent (e.g., bradycardia with hypotension). 18
• Low‑dose dopamine (2–5 µg·kg⁻¹·min⁻¹) should never be employed for renal protection because it lacks efficacy and delays appropriate therapy. 18

Initial Fluid Resuscitation

• Prior to vasopressor initiation, administer at least 30 mL·kg⁻¹ of crystalloid fluid as a rapid bolus. 18

Vasopressor Escalation Algorithm

Monitoring Requirements

• All patients receiving vasopressors should have an arterial catheter placed for continuous blood‑pressure monitoring as soon as feasible. 18

Common Pitfalls to Avoid

• Do not titrate vasopressin – use the fixed 0.03 U·min⁻¹ dose. 18
• Do not use vasopressin as monotherapy – it must be combined with norepinephrine. 18
• Do not employ dopamine for renal protection – this practice is ineffective. 18
• Do not add dopamine as a second‑line agent – guideline‑endorsed second‑line agents are vasopressin or epinephrine. 18

Vasopressin Dosing and Administration in Distributive Shock

Fixed‑Dose Recommendation

• Administer vasopressin as a fixed infusion of 0.03 units/min (1.8 units/hour); the dose is not weight‑based and is used for all adult and pediatric patients requiring vasopressor support in distributive shock【20】【21】.

Indications for Initiation

• Add vasopressin to norepinephrine when MAP remains < 65 mmHg despite adequate fluid resuscitation and norepinephrine therapy; the infusion is started as a non‑titrated continuous rate of 0.03 U/min【22】【20】【21】.
• Specifically, initiate vasopressin when norepinephrine reaches 0.25–0.50 µg/kg/min (≈9–18 µg/min in a 36‑kg patient) and MAP is still < 65 mmHg【20】【21】.

Combination with Norepinephrine

• Vasopressin must be used in combination with norepinephrine and should never replace norepinephrine as the sole initial vasopressor【20】【21】.

Maximum Dose and Salvage Use

• Doses up to 0.04 units/min are permissible, but any dose exceeding 0.03–0.04 U/min should be reserved for salvage therapy when other vasopressor combinations have failed to achieve target MAP【22】【20】【21】.

Infusion Preparation and Rate Calculation

• When the vasopressin solution is diluted to 0.1 units/mL, the required infusion rate is 18 mL/hour to deliver 0.03 U/min【21】.
• When diluted to 1 unit/mL, the required infusion rate is 1.8 mL/hour to deliver 0.03 U/min【21】.
• The infusion is fixed‑rate only; it is not titrated up or down based on blood‑pressure response【20】【21】.

Monitoring and Safety Requirements

• All patients receiving vasopressors should have an arterial catheter placed promptly for continuous blood‑pressure monitoring【20】【21】.

Initial Fluid Resuscitation (Step 1 of the Algorithm)

• Provide at least 30 mL/kg of crystalloid as a rapid bolus (≈1080 mL for a 36‑kg patient) before initiating vasopressor therapy【20】【21】.

Escalation After Vasopressin (Steps 4–5)

• If MAP remains < 65 mmHg despite norepinephrine + vasopressin, add epinephrine at 0.1–0.5 µg/kg/min【20】【21】.
• If hypoperfusion persists despite adequate MAP, add dobutamine (up to 20 µg/kg/min) for inotropic support【20】【21】.

Vasopressin Use in Septic Shock and Related Clinical Situations

Indications and Fixed Dosing

• In adult patients with septic or distributive shock, vasopressin should be started at a fixed dose of 0.03 units/min (1.8 units/h) as a second‑line agent when norepinephrine is being infused at 0.25–0.50 µg/kg/min and the target mean arterial pressure (MAP) ≥ 65 mmHg has not been reached. This dose is non‑titratable for all adults. 23
• The standard dose for septic/distributive shock is the same fixed 0.03 units/min continuous infusion. 23
• The maximum routine dose is 0.04 units/min; any dose above this should be reserved only for rescue therapy after failure of other vasopressors. 23
• Vasopressin must always be administered in combination with norepinephrine; it is never used as monotherapy. 23

Integration into the Septic Shock Resuscitation Algorithm

• Fluid resuscitation: give at least 30 mL/kg of crystalloid before initiating any vasopressor. 23
• Step 3 – Add vasopressin: when norepinephrine reaches 0.25–0.50 µg/kg/min without achieving MAP ≥ 65 mmHg, add vasopressin at the fixed dose of 0.03 units/min. 23
• Step 5 – Inotropic support: if hypoperfusion persists despite an adequate MAP, start dobutamine and titrate up to 20 µg/kg/min. 23

Monitoring Requirements

• Place an arterial catheter as early as possible in any patient receiving vasopressors to allow continuous blood‑pressure monitoring. 23

Safety and Common Pitfalls

• Do not titrate the vasopressin infusion; keep it fixed at 0.03 units/min regardless of hemodynamic response. 23
• Do not exceed 0.04 units/min as a routine dose; higher rates are limited to rescue situations. 23
• Never use vasopressin as the initial vasopressor; it should be added after norepinephrine has been started. 23

Alternative Indications

• Cardiac arrest: a single IV dose of 40 units vasopressin may be used as an alternative to epinephrine, but current evidence shows no superiority in survival with favorable neurological outcome. 24

Situations Where Vasopressin Is Not Indicated

• Anaphylaxis: the recommended first‑line treatment is epinephrine 0.3–0.5 mg IM in the anterolateral thigh; vasopressin has no role in the initial management of anaphylaxis. 25

Special Considerations

• Bradycardia with hypotension: in selected patients with absolute or relative bradycardia and low risk of tachyarrhythmias, dopamine (starting at 5–10 µg/kg/min, titrated up to 20 µg/kg/min) can be considered as an alternative to norepinephrine. 23

Avoidance of Dopamine in Patients with Severe Tachycardia and Profound Hypotension

Contraindications and Risks

• Dopamine should be avoided in patients with severe tachycardia (≈180 bpm) and profound hypotension because it further accelerates heart rate and carries a high risk of life‑threatening arrhythmias. (American Heart Association) 26
• The American Heart Association explicitly warns that dopamine’s adverse‑effect profile includes tachycardia, atrial tachyarrhythmias, and ventricular tachyarrhythmias, rendering it unsuitable when severe tachycardia is already present. 26

Hemodynamic Profile of Dopamine vs. Norepinephrine

• At doses >5 µg·kg⁻¹·min⁻¹ required for meaningful blood‑pressure support, dopamine acts as a potent chronotropic agent that reliably raises heart rate. 26
• Norepinephrine does not reliably increase heart rate because its direct β‑adrenergic stimulation is offset by vagal reflexes triggered by the rise in arterial pressure. (Intensive Care Medicine) 27
• In infants and patients with chronic congestive heart failure, dopamine’s β‑adrenergic effects are markedly reduced, limiting its efficacy during severe shock. 26

Preferred Vasopressor Choices

• Norepinephrine (or epinephrine) is the first‑line vasopressor of choice for patients with marked circulatory instability and decompensated shock, including those with severe tachycardia. (American Heart Association Pediatric Advanced Life Support) 26

Limited Situations Where Dopamine May Be Considered

• Dopamine may be used as an alternative first‑line agent only in highly selected patients who have absolute or relative bradycardia (heart rate < 60–70 bpm) together with hypotension. (American Heart Association) 28
• This bradycardic exception does not apply to patients with a heart rate of 180 bpm. 28

Common Pitfalls to Avoid

• Using low‑dose dopamine (2–5 µg·kg⁻¹·min⁻¹) for “renal protection” has no proven benefit and delays initiation of appropriate vasopressor therapy. 26
• Evidence from comparative trials indicates that dopamine increases mortality and the incidence of arrhythmias in septic shock relative to norepinephrine. (American Heart Association) 26

Guideline‑Based Indications and Thresholds for Initiating Norepinephrine

1. Hemodynamic Thresholds for Vasopressor Initiation

• Norepinephrine is recommended when systolic blood pressure (SBP) ≤ 70 mmHg or when mean arterial pressure (MAP) cannot be maintained ≥ 65 mmHg despite adequate fluid resuscitation. This defines “severe hypotension” that warrants vasopressor support. 29
• In the peri‑operative setting, intra‑operative hypotension is defined as MAP < 65 mmHg or SBP < 90 mmHg sustained for ≈ 15 minutes; such a scenario may prompt vasopressor consideration if fluid resuscitation is insufficient. 30
• A sustained SBP ≤ 70 mmHg or MAP < 65 mmHg for > 15 minutes should trigger norepinephrine initiation after or during fluid replacement. [29][30]

2. Prerequisite Fluid Resuscitation and Contraindications

• Adequate volume status must be assessed first; norepinephrine is relatively contraindicated in pure hypovolemia because it can increase myocardial oxygen demand and worsen tissue perfusion despite raising blood pressure. 29
• Signs of hypovolemia to look for include tachycardia, narrow pulse pressure, poor skin turgor, and low central venous pressure (if measured). 31
• In life‑threatening hypotension (e.g., SBP < 70 mmHg with imminent cerebral or coronary ischemia), norepinephrine may be started concurrently with fluids; this exception does not apply to a BP of 90/60 mmHg. (derived from guideline thresholds)

3. Specific Clinical Contexts

• Cardiogenic shock: norepinephrine may exacerbate myocardial oxygen consumption; use with caution. 29
• Post‑cardiac arrest: norepinephrine is indicated when SBP < 70 mmHg accompanied by low systemic vascular resistance. [29][31]
• Pre‑operative BP of 90/60 mmHg may represent a patient’s baseline; ambulatory measurements should be reviewed before labeling it pathologic. 30
• In patients without major cardiac risk index (RCRI) components, there is little evidence that a peri‑operative BP < 180/110 mmHg increases risk, supporting a conservative approach to vasopressor use. 30

4. Dosage, Administration, and Monitoring

• Starting dose: 0.1–0.5 µg·kg⁻¹·min⁻¹ (approximately 7–35 µg·min⁻¹ for a 70‑kg adult). 29
• Route: administer through a central venous catheter whenever feasible to minimize the risk of extravasation‑related tissue necrosis. [29][32]
• Risks of premature initiation: giving norepinephrine before adequate fluid resuscitation can cause severe peripheral vasoconstriction, reduced renal perfusion, tissue hypoxia, and lactic acidosis even if arterial pressure appears “normal.” 30

5. Alternatives and Misconceptions

• Dopamine: associated with higher mortality and arrhythmias compared with norepinephrine in septic shock; low‑dose dopamine for “renal protection” lacks proven benefit and may delay appropriate therapy. 29

*All statements are based on guideline recommendations from the American College of Cardiology/American Heart Association (as cited). Each bullet point includes the supporting citation(s).

Epinephrine Infusion Guidelines for Adults

Dosage, Preparation, and Administration

• For a 75‑kg adult, initiate epinephrine at 0.1–0.5 µg·kg⁻¹·min⁻¹ (7.5–37.5 µg/min), which corresponds to an infusion rate of 5–22 mL/h when using a standard preparation of 4 mg epinephrine diluted in 250 mL D5W (16 µg/mL); titrate to maintain a mean arterial pressure (MAP) ≥ 65 mmHg. 33
• A typical preparation is 4 mg epinephrine (4 mL of 1 mg/mL) added to 250 mL D5W, yielding a concentration of 16 µg/mL. 33
• Administer the infusion through a central venous catheter whenever feasible, because peripheral extravasation can cause tissue necrosis and sloughing. 33
• Starting dose of 0.1 µg·kg⁻¹·min⁻¹ (≈ 7.5 µg/min) translates to roughly 28 mL/h with the 16 µg/mL solution. 33
• A moderate dose of 0.3 µg·kg⁻¹·min⁻¹ (≈ 22.5 µg/min) translates to roughly 84 mL/h. 33
• The maximum typical dose of 0.5 µg·kg⁻¹·min⁻¹ (≈ 37.5 µg/min) translates to roughly 140 mL/h. 33

Titration and Monitoring

• Continuously titrate the infusion at the bedside to achieve the target MAP ≥ 65 mmHg while monitoring for adverse effects such as tachycardia, arrhythmias, and myocardial ischemia. 33

Clinical Indications

• Severe hypotension (systolic BP < 70 mmHg) with low systemic vascular resistance, especially in septic shock after adequate fluid resuscitation (≥ 30 mL/kg crystalloid). 33
• Symptomatic bradycardia that does not respond to atropine and transcutaneous pacing, or when pacing is unavailable. 33
• Anaphylaxis with hemodynamic instability or respiratory distress; intravenous epinephrine infusion is reserved for refractory cases after the recommended intramuscular dose (0.3–0.5 mg in the anterolateral thigh). 34

Safety and Compatibility

• Do not mix epinephrine with sodium bicarbonate or other alkaline solutions, as catecholamines are inactivated in alkaline environments. 33
• If extravasation occurs, immediately infiltrate the site with 5–10 mg phentolamine diluted in 10–15 mL normal saline to prevent tissue necrosis. 33
• Use with caution in patients with ischemic heart disease because epinephrine increases myocardial oxygen demand and may precipitate angina or myocardial infarction. 33

Anaphylaxis Management Specifics

• Do not delay intramuscular epinephrine (0.3–0.5 mg) in anaphylaxis; intravenous infusion should be added only if hypotension persists despite repeated intramuscular doses. 34