Table 2.

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

Neurological level	Dysfunction
C1–C3	Likely 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–C4	Diaphragm 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
C5	Independent 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
C6–8	Independent breathing People with lesions caudal to C7 typically can augment inspiration and cough with accessory muscles, particularly pectoralis major and minor
T1–T4	Inspiratory capacity and forced expiration supported by intercostal activity; however, cough efficacy remains reduced secondary to abdominal (expiratory) weakness
T5–T12	Progressive relative improvement in muscle strength at descending lesion levels Minimal disruption to autonomic dysfunction affecting the cardiovascular system below T6
T12	Respiratory function essentially comparable to that of an able-bodied person