Hypotension and Bradycardia After a C5 Spinal Cord Injury
Ms. T, 24, is admitted after a rollover MVC with a C5 fracture and ASIA B spinal cord injury, 6 hours post-injury. BP is 84/46 mmHg, HR 48, SpO2 94% on 2 L, temp 35.8°C, skin warm and dry, lactate 1.6 mmol/L, Hgb 11.0 g/dL, urine output 60 mL/hr. CT shows no other major injuries. She is awake and breathing spontaneously with vital capacity 18 mL/kg and NIF −30 cmH2O, and has intermittent bradycardic pauses to 38 beats/min.
1. Differentiate neurogenic shock from hemorrhagic shock using the data provided.
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The combination of hypotension with bradycardia, warm dry skin, normal lactate (1.6), stable Hgb (11.0), and good urine output in a C5 injury strongly favors neurogenic shock from loss of sympathetic tone (injury above T6).
Hemorrhagic shock typically produces tachycardia, cool clammy skin, rising lactate, falling Hgb, and oliguria. A high cervical injury can mask tachycardia, so hemorrhage is not excluded by heart rate alone. However, the normal lactate, stable Hgb, adequate urine output, and absence of other injuries on CT make hemorrhage much less likely. Continue serial Hgb and repeat imaging if concerned; treat neurogenic shock while ruling out bleeding.
2. What MAP goal would you recommend, and how would you achieve it? What would you avoid?
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Target MAP 85–90 mmHg for 5–7 days after acute spinal cord injury to support cord perfusion.
Norepinephrine is first-line because it provides both alpha- and beta-adrenergic support and is less likely than phenylephrine to worsen reflex bradycardia. Use cautious crystalloid boluses (e.g., 250–500 mL) rather than large-volume resuscitation to avoid pulmonary edema. Monitor invasively (arterial line, urine output, lactate, respiratory status).
Avoid hypotension, hypoxia, and volume overload. For symptomatic bradycardia or pauses, give atropine 0.5–1 mg IV and have pacing pads available; avoid vagal stimuli such as suctioning without preoxygenation.
3. Outline your respiratory monitoring plan and the thresholds that would prompt intubation. How would you manage the bradycardia?
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Monitor vital capacity, NIF, respiratory rate, SpO2, and ABG every 4–6 hours initially, and continuously with pulse oximetry. Her current VC (18 mL/kg) and NIF (−30 cmH2O) are acceptable but can deteriorate as edema evolves.
Intubate for VC <15 mL/kg, NIF weaker than −20 to −25 cmH2O, PaO2 <70 mmHg on oxygen, PaCO2 >45 mmHg, or clinical distress/fatigue. Reassess after any change.
For bradycardia: treat symptoms or HR <40–50 with hypotension using atropine 0.5–1 mg IV, preoxygenate before suctioning, keep the head midline, and avoid vagal triggers. If refractory, use transcutaneous pacing and consider a temporary pacemaker. Correct hypoxia and hypothermia, which worsen bradycardia.