How do you manage a patient with hypotension?

Management of Hypotension

The first-line treatment for hypotension is administration of balanced crystalloids (10-20 mL/kg) followed by norepinephrine (0.05-2 mcg/kg/min) if fluid resuscitation is inadequate to maintain target blood pressure. 1

Initial Assessment and Management

Identify the Cause

• Determine whether hypotension is due to:
  • Hypovolemia (hemorrhage, dehydration, third-spacing)
  • Cardiogenic factors (myocardial dysfunction)
  • Distributive causes (sepsis, anaphylaxis, neurogenic shock)
  • Obstructive causes (pulmonary embolism, tension pneumothorax, cardiac tamponade)
  • Medication effects or toxins

Fluid Resuscitation

• Administer balanced crystalloids as first-line treatment:
  • Initial bolus of 10-20 mL/kg (maximum 1,000 mL) 2
  • Assess response to fluid using dynamic variables (pulse pressure variation, stroke volume variation) and clinical signs of tissue perfusion 1
  • Continue fluid administration as long as hemodynamic factors improve 1

Blood Pressure Targets

• Target MAP ≥65 mmHg for most patients 2
• Consider higher targets for:
  • Patients with traumatic brain injury 1
  • Patients with pre-existing hypertension 1
• Consider permissive hypotension (SBP 80-90 mmHg) in trauma patients until hemorrhage is controlled 2

Vasopressor Therapy

First-Line Vasopressor

• Norepinephrine is recommended as the first-line vasopressor (0.05-2 mcg/kg/min) 2, 1, 3
• Start vasopressors if hypotension persists after adequate fluid resuscitation 2
• For administration:
  • Dilute 1 mg in 1,000 mL of 5% dextrose to produce 1 mcg/mL concentration 3
  • Administer into a large vein 3
  • Titrate every 10-15 minutes to achieve desired MAP 3

Second-Line Vasopressors

• Vasopressin can be added to norepinephrine to raise MAP or decrease norepinephrine dosage 2, 1
• Epinephrine can be added to or substituted for norepinephrine when an additional agent is needed 1
• Dobutamine should be added for evidence of myocardial dysfunction 2, 1

Special Clinical Scenarios

Septic Shock

• Administer at least 30 mL/kg of crystalloid within the first 3 hours 1
• Start norepinephrine if hypotension persists after fluid resuscitation 2
• Consider hydrocortisone (50 mg IV q6h or 200-mg infusion) for refractory shock requiring high-dose vasopressors 2

Hemorrhagic Shock

• Use restricted volume replacement strategy and permissive hypotension (SBP 80-90 mmHg) until bleeding is controlled 2
• If target blood pressure cannot be achieved with fluids, add norepinephrine 2
• Avoid hypotonic solutions like Ringer's lactate in patients with severe head trauma 2

Cardiogenic Shock

• Perform bedside echocardiography to evaluate volume status and cardiac function 2
• Consider dobutamine for myocardial dysfunction 2, 1
• Use invasive hemodynamic monitoring for adequate assessment of cardiac function and titration of vasopressors 2

Anaphylactic Shock

• Administer epinephrine as early as possible 1
• Consider epinephrine infusion if multiple doses are required 1
• Add chlorphenamine and hydrocortisone as secondary management 1

Monitoring and Reassessment

• Monitor continuous cardiac telemetry and pulse oximetry in patients with significant hypotension 2
• Consider invasive hemodynamic monitoring (arterial and central venous catheter) for adequate assessment of cardiac function and titration of vasopressors 2
• Perform echocardiography to assess cardiac function in patients with persistent hypotension 2
• Assess end-organ perfusion through:
  • Base excess levels
  • Arterial lactate measurements
  • Urine output
  • Neurologic assessment 2

Pitfalls and Caveats

• Avoid excessive fluid administration which may lead to tissue edema and hypoxemia rather than increased oxygen delivery 4
• Recognize that patients with pre-existing hypertension may require higher blood pressure targets 1
• Be cautious with vasopressors in trauma patients as they may alter organ perfusion by potentiating vasoconstriction 2
• Consider adrenal insufficiency in patients with vasopressor-resistant hypotension 2, 5
• Wean vasopressors incrementally over time (e.g., decreasing doses every 30 minutes over a 12-24 hour period) after hemodynamic stabilization 3

By following this algorithmic approach to hypotension management, clinicians can effectively restore tissue perfusion while minimizing complications associated with both hypotension and its treatment.