What medical interventions and drugs are used to treat hypotension?

Medical Interventions and Drugs for Hypotension

First-Line Vasopressor Therapy

Norepinephrine is the first-choice vasopressor for treating hypotension, targeting a mean arterial pressure (MAP) of 65 mm Hg. 1, 2, 3, 4, 5

• Norepinephrine should be initiated as the primary vasopressor agent after rapid assessment of volume status 1, 3, 4
• The FDA approves norepinephrine for blood pressure control in acute hypotensive states including septicemia, myocardial infarction, spinal anesthesia, and as an adjunct in cardiac arrest 5
• Typical starting dose is 0.1–0.5 mcg/kg/min (7–35 mcg/min in a 70-kg adult), then titrate to effect 1
• Central line administration is strongly preferred to minimize risk of tissue necrosis from extravasation 1, 3

Fluid Resuscitation Strategy

Crystalloids are the fluid of choice for initial resuscitation, with an initial bolus of 30 mL/kg (approximately 1-2 L in adults) administered rapidly. 1, 4

• Balanced crystalloids (lactated Ringer's solution) or normal saline should be used for fluid resuscitation 1, 2, 4
• Fluid challenge technique should be applied, continuing administration as long as hemodynamic improvement occurs based on dynamic or static variables 1
• Albumin may be added to crystalloids when patients require substantial amounts of crystalloids, though this is a weak recommendation 1
• Hydroxyethyl starches are strongly contraindicated for intravascular volume replacement 1
• Perform passive leg raise testing before reflexive fluid administration, as fluid worsens outcomes in non-hypovolemic patients 2, 4

Second-Line Vasopressor Options

When norepinephrine alone is insufficient, add vasopressin (up to 0.03 units/min) or epinephrine as the second-line agent. 1, 3, 4

• Vasopressin at 0.03 units/minute can be added to norepinephrine to raise MAP or decrease norepinephrine dosage 1
• Vasopressin should not be used as the single initial vasopressor, and doses higher than 0.03–0.04 units/minute should be reserved for salvage therapy 1
• Epinephrine (0.1–0.5 mcg/kg/min) can be added to or substituted for norepinephrine when additional agents are needed 1
• Epinephrine is particularly useful for severe hypotension (systolic BP <70 mm Hg) and anaphylaxis with hemodynamic instability 1

Dopamine: Limited Role

Dopamine should only be used as an alternative vasopressor in highly selected patients with low risk of tachyarrhythmias and absolute or relative bradycardia. 1, 4

• Starting dose is 5–10 mcg/kg/min 1
• Low-dose dopamine is strongly contraindicated for renal protection, as it provides no benefit 1
• Dopamine carries higher risk of tachyarrhythmias compared to norepinephrine 1, 6
• Tricyclic antidepressants potentiate dopamine's cardiovascular effects, and butyrophenones/phenothiazines can suppress its vasodilatory effects 6

Inotropic Support for Low Cardiac Output

Dobutamine (starting at 2-5 mcg/kg/min) should be added when hypotension is due to low cardiac output states, after blood pressure is stabilized with norepinephrine. 2, 3, 4

• Dobutamine is initiated without a bolus dose 2
• The drug may cause less tachycardia than other inotropes, though milrinone is an alternative if tachycardia is problematic 1, 3
• Dobutamine should not be used as monotherapy in hypotensive states, as its vasodilating effects can worsen hypotension 1

Phenylephrine: Restricted Use

Phenylephrine (0.5–2.0 mcg/kg/min) should be avoided as first-line therapy except when tachycardia is present, as reflex bradycardia can worsen cardiac output. 1, 2

• Phenylephrine is reserved for circumstances where norepinephrine causes serious arrhythmias or when cardiac output is known to be high 1
• It is used to treat severe hypotension (systolic BP <70 mm Hg) with low total peripheral resistance 1

Adjunctive Corticosteroid Therapy

Hydrocortisone 50 mg IV every 6 hours (or 200-mg infusion) should be considered for refractory shock requiring high-dose vasopressors. 1

• This is based on trials showing earlier shock reversal and potential mortality benefit 1
• Treatment duration is 7 days or until ICU discharge 1
• Consider screening for adrenal insufficiency in patients with cirrhosis and refractory shock 1

Critical Monitoring Requirements

Continuous monitoring of ECG, blood pressure, oxygen saturation, urine output, and serum lactate is mandatory when using vasopressors. 1, 2, 3, 4

• Invasive hemodynamic monitoring (arterial and central venous catheter) may be needed for adequate assessment and titration 1
• Echocardiography should be performed to evaluate volume status, cardiac function, and mechanical complications 2, 3
• Monitor response through clinical parameters (peripheral perfusion, mental status) and laboratory markers (lactate, SvO2) 3, 4

Essential Pitfalls to Avoid

• Never administer vasodilators when systolic BP is <90 mm Hg, as this worsens hypotension and outcomes 2
• Avoid beta-blockers in hypotensive patients with low output states, as they worsen pump failure 2
• Do not give reflexive fluid boluses without assessing fluid responsiveness, as this worsens outcomes in non-hypovolemic patients 2, 4
• Avoid normotensive resuscitation with large volumes of crystalloids, as hypotensive resuscitation to MAP 65 mm Hg requires smaller volumes and may be equally effective 7
• Never use low-dose dopamine for renal protection—this practice has no evidence of benefit 1