**2.4 Respiratory**

The level of spinal cord injury usually determines the degree of respiratory support required in these patients. Complete injury above the level of C3 results in apneic respiratory arrest and death in the absence of prompt ventilatory support. Less-severe ventilatory impairment is associated with injuries below the C5 vertebra with various levels of respiratory failure for injuries between C3 and C5.

### **2.5 Cardiovascular**

Involvement of cardiac accelerator fibers (T1–T4) is the cause of bradycardia and decreased myocardial contractility in these patients, often resulting in systemic hypotension and subsequent reduced spinal cord perfusion.
