What is the immediate management for a patient with hypotension?

Immediate Management of Hypotension

Begin immediate fluid resuscitation with 30 mL/kg of crystalloid (lactated Ringer's or normal saline) within the first 3 hours, followed by norepinephrine targeting a mean arterial pressure of 65 mm Hg if hypotension persists after initial fluid challenge. 1, 2

Initial Assessment and Resuscitation

Fluid Resuscitation - First Priority

• Administer at least 30 mL/kg (approximately 1-2 L in adults) of intravenous crystalloid fluid within the first 3 hours for sepsis-induced hypoperfusion or hypotension 1, 2
• Give fluid challenges of 500-1000 mL of crystalloid over 30 minutes, with more rapid and larger volumes required in severe hypotension 1, 3
• Lactated Ringer's solution is preferred over normal saline as it is associated with improved survival (12.2% vs 15.9% mortality) and more hospital-free days in sepsis-induced hypotension 4, 5
• Balanced crystalloids should be used instead of normal saline to avoid hyperchloremic acidosis 1, 5
• Continue fluid administration guided by frequent reassessment of hemodynamic status including heart rate, blood pressure, urine output, and lactate levels 1, 2

Critical caveat: Blood volume depletion must be corrected as fully as possible before vasopressors are administered, except in emergency situations requiring maintenance of coronary and cerebral perfusion 6

Vasopressor Therapy - When Fluids Are Insufficient

• Norepinephrine is the first-choice vasopressor when fluid resuscitation does not achieve target blood pressure 2, 3
• Target a mean arterial pressure (MAP) of ≥65 mm Hg in septic shock and most hypotensive states 1, 2
• Start norepinephrine at 0.1-0.5 mcg/kg/min (typical starting dose 8-12 mcg/min), titrated to effect 2, 6
• Central line administration is strongly preferred to minimize risk of tissue necrosis from extravasation 2, 6
• Dilute norepinephrine in 5% dextrose-containing solutions (4 mg in 1000 mL = 4 mcg/mL concentration) 6

Context-Specific Modifications

For hemorrhagic shock (trauma without brain injury):

• Use restricted volume replacement targeting systolic blood pressure of 80-90 mm Hg until surgical hemorrhage control is achieved 1, 3, 7
• Avoid aggressive fluid resuscitation as it increases mortality by disrupting clot formation 1, 3
• Give crystalloid in 250 mL aliquots to restore radial pulse or maintain systolic BP ~80 mm Hg (permissive hypotension) 7

For traumatic brain injury:

• Maintain MAP ≥80 mm Hg to ensure adequate cerebral perfusion pressure 3, 8
• Do NOT use permissive hypotension in head trauma patients 3

For anaphylactic shock:

• Administer epinephrine 20 mcg IV bolus for Grade II reactions (moderate hypotension/bronchospasm), escalating to 50 mcg if inadequate response at 2 minutes 1
• Give 500 mL crystalloid rapid bolus and repeat as needed 1
• For Grade III reactions (life-threatening), use epinephrine 50-100 mcg IV bolus with 1 L crystalloid rapid bolus 1
• If no IV access, give epinephrine 300 mcg intramuscularly 1

Escalation Strategy for Refractory Hypotension

Second-Line Vasopressors

• Add vasopressin (0.03 units/min) or epinephrine when norepinephrine alone is insufficient to maintain target MAP 2, 3
• Vasopressin should not be used as the single initial vasopressor but can be added to reduce norepinephrine requirements 2
• Phenylephrine is reserved for hypotension with tachycardia or as salvage therapy, as it causes reflex bradycardia 3

Inotropic Support

• Add dobutamine (starting at 2-5 mcg/kg/min) when hypotension is due to low cardiac output after blood pressure is stabilized with norepinephrine 2, 3
• Dobutamine is initiated without a bolus dose and may cause less tachycardia than other inotropes 2
• Consider echocardiography to evaluate cardiac function and guide inotrope selection 2

Adjunctive Corticosteroids

• Administer hydrocortisone 50 mg IV every 6 hours (or 200 mg continuous infusion) for refractory shock requiring high-dose vasopressors 2
• Treatment duration is 7 days or until ICU discharge 2

Monitoring Requirements

• Continuous monitoring of ECG, blood pressure, oxygen saturation, urine output, and serum lactate is mandatory when using vasopressors 2, 3
• Invasive arterial blood pressure monitoring is recommended for precise titration of vasoactive agents 2, 3
• Use dynamic variables (passive leg raise test, pulse pressure variation) over static variables to predict fluid responsiveness 1, 3
• The passive leg raise test has a positive likelihood ratio of 11 and 92% specificity for determining fluid responsiveness 3, 8

Critical Pitfalls to Avoid

• Do not give vasopressors to hypovolemic patients except as an emergency measure to maintain coronary and cerebral perfusion until volume replacement is completed 6
• Avoid reflexive fluid administration without assessing fluid responsiveness, as approximately 50% of hypotensive patients are not hypovolemic 3, 8
• Do not use hypotonic solutions (Ringer's lactate) in severe head trauma patients 1
• Avoid colloids due to adverse effects on hemostasis 1
• Do not use permissive hypotension in traumatic brain injury patients 3
• Avoid abrupt withdrawal of norepinephrine; reduce gradually once adequate blood pressure is maintained 6