Table 2

Neurological level for complete SCI, typical respiratory impairment and support [123, 155, 159, 160]

Neurological levelDysfunction
C1–C3Likely full time, ventilator dependent secondary to severe diaphragm weakness (paralysis)
May be able to come off ventilation for brief period if able to adequately self-ventilate using frog/GPB
Potential candidate for diaphragm pacing [155]
C3–C4Diaphragm function will be impaired, reducing tidal volume and vital capacity
Periods of unassisted ventilation (ventilator-free time) are likely and may be adequately supported with nocturnal ventilation alone
Domiciliary ventilatory support may be noninvasive, particularly if lung volumes are high enough during day while seated
C5Independent respiration possible in long term although initial ventilatory support common
Diaphragm function intact but intercostal and abdominal muscle paralysis results in decreased lung volumes, and cough strength and effectiveness
C6–8Independent breathing
People with lesions caudal to C7 typically can augment inspiration and cough with accessory muscles, particularly pectoralis major and minor
T1–T4Inspiratory capacity and forced expiration supported by intercostal activity; however, cough efficacy remains reduced secondary to abdominal (expiratory) weakness
T5–T12Progressive relative improvement in muscle strength at descending lesion levels
Minimal disruption to autonomic dysfunction affecting the cardiovascular system below T6
T12Respiratory function essentially comparable to that of an able-bodied person