A patient with C4 AIS A SCI who has partial phrenic nerve innervation and may be able to wean from the ventilator would benefit most from which device?

A patient with C4 AIS A SCI who has partial phrenic nerve innervation and may be able to wean from the ventilator would benefit most from which device?

• A. Tenodesis splint
• B. Phrenic nerve stimulator
• C. Environmental control unit
• D. Rocker knife

Answer: (B)

The situation tests how to support respiration in a high cervical spinal cord injury when there is partial diaphragmatic innervation. The phrenic nerve, which comes from the C3–C5 levels, controls the diaphragm. If there’s some preserved phrenic function at C4, a device that directly stimulates the phrenic nerve can evoke diaphragmatic contractions, effectively acting as a diaphragm pacer. This electrical stimulation can augment breathing and facilitate weaning from the ventilator by providing diaphragmatic effort even when voluntary drive is impaired. Among the options, the phrenic nerve stimulator directly targets the impaired respiratory mechanism and helps reduce ventilator dependence. The other devices address non-respiratory functions—tenodesis splints improve hand function, an environmental control unit aids independence in daily activities, and the rocker knife is for assistive feeding—so they don’t address the core respiratory limitation in this scenario.

The situation tests how to support respiration in a high cervical spinal cord injury when there is partial diaphragmatic innervation. The phrenic nerve, which comes from the C3–C5 levels, controls the diaphragm. If there’s some preserved phrenic function at C4, a device that directly stimulates the phrenic nerve can evoke diaphragmatic contractions, effectively acting as a diaphragm pacer. This electrical stimulation can augment breathing and facilitate weaning from the ventilator by providing diaphragmatic effort even when voluntary drive is impaired. Among the options, the phrenic nerve stimulator directly targets the impaired respiratory mechanism and helps reduce ventilator dependence. The other devices address non-respiratory functions—tenodesis splints improve hand function, an environmental control unit aids independence in daily activities, and the rocker knife is for assistive feeding—so they don’t address the core respiratory limitation in this scenario.