LUNG FUNCTION-TETRAPLEGIA

SUMMARY

1. Forced vital capacity (FVC) during the acute phase of cervical injury is noted to decrease 24-31% when compared to the normal values secondary to paradoxical respirations.

2. With development of intercostal and abdominal spasticity, FVC can improve to 50-60% of predicted normal value.

3. Tetraplegics usually develop restrictive lung patterns:
- All volumes shrink (except residual volume)
- If vital capacity (VC) < 1 L: consider ventilation mechanically
- Once VC > 15 to 20 mL/kg, can usually wean off ventilator

4. Signs of impending respiratory failure:
- Increased respiratory rate with decreased tidal volume
- Decreased FVC < 15 mL/kg body weight
- Neurological level C3 or higher
- Patient cannot count to 15 slowly

Reference(s)

Barrett, K.E., Barman, S.M., Boitano, S., Brooks, H.L., Weitz, M., Brian Patrick Kearns, Ganong, W.F. and Mcgraw-Hill Education (Firm (2016). Ganong’s review of medical physiology. 25th ed. New York: Mcgraw Hill Education.
Hall, J.E. and Hall, M.E. (2020). Guyton And Hall Textbook Of Medical Physiology. 14th ed. S.L.: Elsevier - Health Science.
West, J.B. and Luks, A.M. (2021). West’s Pulmonary Pathophysiology. Lippincott Williams & Wilkins.