From the Guidelines
Spinal cord injuries at the C6-C7 level commonly cause significant cardiovascular manifestations due to disruption of sympathetic nervous system control, and the primary cardiovascular issue is neurogenic shock, characterized by bradycardia and hypotension. The management of these cardiovascular manifestations should prioritize maintaining mean arterial pressure level up to 70 mmHg during the first week to limit the risk of worsening of the neurological deficit, as suggested by experts 1.
Key Cardiovascular Issues
- Neurogenic shock: characterized by bradycardia and hypotension due to loss of sympathetic tone and unopposed vagal activity, typically occurring in the acute phase (first 1-4 weeks) and requiring prompt treatment with IV fluids and vasopressors like norepinephrine or phenylephrine.
- Long-term cardiovascular complications: include orthostatic hypotension, autonomic dysreflexia, and temperature dysregulation.
Management Strategies
- Orthostatic hypotension can be managed with compression stockings, abdominal binders, and medications like midodrine (starting at 2.5mg three times daily) 1.
- Autonomic dysreflexia presents as sudden severe hypertension triggered by noxious stimuli below the injury level and requires immediate identification and removal of the trigger, along with seated positioning and, if needed, antihypertensives like nifedipine 10mg sublingually.
- Temporary pacing is another potential approach for treating hemodynamically significant sinus bradycardia associated with spinal cord injury, as mentioned in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Respiratory Considerations
- A weaning protocol for mechanical ventilation specifically reduces mechanical ventilation times and length of stay in intensive care, and experts suggest performing a tracheostomy to accelerate ventilatory weaning within the first 7 days in patients with upper level spinal cord injury (C2–C5), and only after one or more tracheal extubation failures in patients with lower cervical spinal cord injury (C6–C7) 1.
From the Research
Cardiovascular Manifestations of Spinal Cord Injury Level C6-C7
- The level of cervical spinal cord injury (CSCI) can be used to predict the need for a cardiovascular intervention 2.
- Patients with high CSCI (C1-C5) had a significantly greater requirement for a cardiovascular intervention compared with patients with lower injuries (C6-C7) 2.
- Neurogenic shock, defined as bradycardia with hypotension, was present in 24% of patients with low CSCI (C6-C7) 2.
- Orthostatic hypotension is a common complication following spinal cord injury, and its management is crucial to prevent cardiovascular mortality 3.
- Midodrine, a potent vasopressor, has been suggested as a therapeutic option for managing symptoms in spinal cord injury patients, including those with C6-C7 injuries 4, 5, 6.
Management of Cardiovascular Manifestations
- Midodrine and fludrocortisone can be used to manage hypotension in patients with spinal cord injury, including those with C6-C7 fractures 5.
- Theophylline and aminophylline, methylxanthine derivatives, can also be used to manage hypotension and bradycardia in patients with spinal cord injury 4.
- Functional electrical stimulation is a non-pharmacologic intervention with some evidence to support its utility in managing orthostatic hypotension in patients with spinal cord injury 6.
- Further research is needed to quantify the efficacy of treatment for orthostatic hypotension in subjects with spinal cord injury, especially for pharmacologic interventions that have been shown to be effective in non-SCI conditions 6.