What intervention is indicated to manage hypotension in a patient with a suspected cervical spine injury?

Management of Hypotension in Cervical Spine Injury with Neurogenic Shock

The correct intervention is norepinephrine (levophed) to manage hypotension in this patient with cervical spine injury and neurogenic shock. 1, 2

Clinical Context and Pathophysiology

This 23-year-old woman has a C5 cervical spine injury with hypotension that persists despite fluid resuscitation, indicating neurogenic shock rather than hypovolemic shock. Her normal hemoglobin (14 g/dL) and lack of response to normal saline bolus confirm this is not hemorrhagic shock 2.

• Cervical spinal cord injuries disrupt sympathetic outflow, causing loss of vasomotor tone and resulting in hypotension with relative bradycardia 3
• The loss of sympathetic control below the injury level leads to peripheral vasodilation and inadequate compensatory vasoconstriction 4, 3

Blood Pressure Targets in Acute Cervical Spine Injury

Maintaining adequate mean arterial pressure (MAP) is critical to prevent secondary spinal cord injury from hypoperfusion:

• The American College of Cardiology recommends maintaining systolic blood pressure >110 mmHg during initial assessment to reduce mortality 2
• Target MAP ≥70 mmHg continuously during the first week post-injury to limit neurological deterioration 2
• The American Association of Neurological Surgeons/Congress of Neurological Surgeons recommends targeting MAP >85 mmHg within the first 5-7 days after spinal cord injury, though this higher target is based on limited evidence 1
• French guidelines suggest a more conservative MAP >70 mmHg during the first week, noting insufficient evidence for levels over 70 mmHg 1

Why Norepinephrine is the Correct Choice

Norepinephrine is the vasopressor of choice for neurogenic shock because:

• It provides both alpha-adrenergic vasoconstriction (to restore vascular tone) and beta-adrenergic cardiac stimulation 5
• FDA-approved for blood pressure control in acute hypotensive states including spinal anesthesia and profound hypotension 5
• Should be administered after fluid resuscitation has been attempted, as in this case 5
• Requires continuous arterial pressure monitoring via arterial catheter, as MAP is below target approximately 25% of the time without close monitoring 1

Dosing and Administration

• Dilute 4 mg/4 mL in 1,000 mL of 5% dextrose solution (4 mcg/mL concentration) 5
• Initial dose: 2-3 mL/minute (8-12 mcg/minute of base) 5
• Titrate to maintain systolic blood pressure 80-100 mmHg or MAP >70-85 mmHg 5, 1
• Administer through a large central vein with continuous infusion 5

Why Other Options Are Incorrect

Cardiac Pacing (Option A)

• While cervical spinal cord injury can cause bradyarrhythmias and even recurrent asystole requiring permanent pacemaker placement, this is indicated for symptomatic bradyarrhythmic events still occurring 2 weeks after injury, not for acute hypotension management 6
• The primary problem here is loss of vasomotor tone, not primary cardiac dysfunction 3

Transfusion of PRBCs (Option C)

• Her hemoglobin is normal at 14 g/dL, indicating no significant blood loss 2
• The hypotension persisted despite normal saline bolus, confirming this is neurogenic rather than hemorrhagic shock 2
• Transfusion would not address the underlying loss of sympathetic vascular tone 3

Steroids/Methylprednisolone (Option D)

• High-dose methylprednisolone for acute spinal cord injury is no longer recommended due to lack of proven benefit and significant risks
• This does not address the acute hemodynamic instability from neurogenic shock
• Vasopressor support is the immediate priority for hypotension management 1, 2

Critical Monitoring and Duration

• Continuous arterial blood pressure monitoring is essential 1
• The correlation between MAP level and neurological improvement is strongest in the first 2-3 days after admission 1
• Most guidelines recommend maintaining elevated MAP for 5-7 days post-injury 1
• Hypotension increases mortality risk and can cause anterior cord syndrome from hypoperfusion of the anterior spinal artery 7, 2

Important Caveat

Failing to maintain systolic blood pressure >110 mmHg significantly increases mortality risk in cervical spine injury patients. 2 Vasopressor therapy should not be delayed once hypovolemia has been addressed, as secondary spinal cord injury from hypoperfusion is a preventable cause of neurological deterioration 7, 1.