What is the immediate treatment for a patient with hypotension?

Immediate Treatment of Hypotension

For a patient presenting with low blood pressure, immediately identify the underlying cause (hypovolemia, vasodilation, bradycardia, or low cardiac output) and initiate cause-directed therapy: administer a 500 mL crystalloid bolus for suspected hypovolemia, start norepinephrine at 0.1-0.5 mcg/kg/min for vasodilation, give atropine for symptomatic bradycardia, or initiate dobutamine 2-5 mcg/kg/min for low cardiac output states. 1, 2

Initial Assessment and Rapid Diagnosis

The first critical step is determining the physiological mechanism causing hypotension, as treatment differs fundamentally based on the underlying cause 1, 3:

• Assess for hypovolemia: Look for tachycardia, oliguria, decreased skin turgor, and history of fluid losses 3
• Assess for vasodilation: Warm extremities with low blood pressure despite adequate filling 3
• Assess for low cardiac output: Cold extremities, cyanosis, decreased mentation, pulmonary congestion 3
• Check ECG immediately: Rule out bradycardia or arrhythmias 3

Perform a passive leg raise test to determine fluid responsiveness before reflexive fluid administration—this test has a positive likelihood ratio of 11 and pooled specificity of 92% 1. Approximately 50% of hypotensive patients are not hypovolemic, making this assessment critical 2.

Cause-Directed Treatment Algorithm

For Hypovolemia

• Administer an initial crystalloid bolus of 500 mL in adults (or 10-20 mL/kg in children) using lactated Ringer's solution or normal saline 1, 2
• Continue fluid administration only if hemodynamic improvement occurs with each bolus 2
• In septic shock specifically, give at least 30 mL/kg within the first 3 hours 4
• Consider albumin when substantial crystalloid volumes are required 2

Critical pitfall: Avoid reflexive fluid administration without assessing fluid responsiveness, as this worsens outcomes in non-hypovolemic patients 3, 2. Do not give additional fluid boluses in patients with cardiac dysfunction or pulmonary edema 1.

For Vasodilation (Distributive Shock)

• Start norepinephrine immediately as the first-line vasopressor at 0.1-0.5 mcg/kg/min (or 8-12 mcg/min), targeting a mean arterial pressure of 65 mmHg 1, 2, 5
• Dilute 4 mg norepinephrine in 1000 mL of 5% dextrose solution (yielding 4 mcg/mL) 5
• Administer via central line when possible to minimize extravasation risk 2, 5
• If hypotension persists, add vasopressin 0.03 units/min as second-line therapy 1, 2

In septic shock specifically, norepinephrine is the definitive first-choice vasopressor with strong evidence 4, 2.

For Bradycardia

• Treat with atropine or glycopyrronium as first-line anticholinergic therapy 1
• Correct any underlying rhythm disturbances or conduction abnormalities immediately 3

For Low Cardiac Output

• Start dobutamine at 2-5 mcg/kg/min without bolus after blood pressure is stabilized with norepinephrine 1, 3, 2
• Dobutamine causes less tachycardia than other inotropes; consider milrinone if tachycardia is problematic 2
• Add norepinephrine if hypotension persists despite inotropic support 1, 3

Critical pitfall: Avoid beta-blockers in hypotensive patients with low cardiac output, as they worsen pump failure 3. Avoid vasodilators when systolic blood pressure is <90 mmHg 3.

Context-Specific Modifications

Trauma Patients

• In trauma without brain injury: Use restricted volume replacement targeting systolic blood pressure of 80-90 mmHg until major bleeding is controlled 1
• In traumatic brain injury: Maintain mean arterial pressure of at least 80 mmHg to ensure adequate cerebral perfusion 1
• Aggressive fluid resuscitation increases mortality in trauma patients without brain injury 1

Anaphylaxis

• Administer epinephrine 50 mcg IV (0.5 mL of 1:10,000 solution) immediately for life-threatening hypotension 4
• Give 500 mL crystalloid as rapid bolus and repeat if inadequate response 4
• If IV access is lost, give epinephrine 300 mcg IM 4
• Escalate epinephrine dosing (doubling bolus dose) if inadequate response after 10 minutes 4

Acute Heart Failure

• Avoid diuretics until adequate perfusion is restored 3
• Avoid vasodilators when systolic blood pressure is <90 mmHg 3

Refractory Shock

• Add hydrocortisone 50 mg IV every 6 hours (or 200 mg infusion) for shock requiring high-dose vasopressors 2
• Consider epinephrine as second-line agent when norepinephrine and vasopressin are insufficient 2

Essential Monitoring Requirements

When using vasopressors and inotropes, implement continuous monitoring including 3, 2:

• ECG and invasive arterial blood pressure monitoring
• Oxygen saturation and urine output
• Serum lactate levels
• Central venous pressure when available
• Echocardiography to evaluate volume status and cardiac function

Critical pitfall: Phenylephrine should be reserved for hypotension with tachycardia only, as it causes reflex bradycardia that can worsen cardiac output 1, 3.

Titration and Duration

• Titrate all vasoactive agents to effect rather than fixed doses 1
• Target mean arterial pressure of 65 mmHg in most cases, though higher targets (80 mmHg) are needed in traumatic brain injury 1, 2
• Reduce vasopressor infusions gradually once adequate blood pressure and tissue perfusion are maintained, avoiding abrupt withdrawal 5