Philadelphia versus Miami-J cervical collar's impact on pulmonary function

Am J Emerg Med. 2021 May;43:59-61. doi: 10.1016/j.ajem.2021.01.043. Epub 2021 Jan 22.


Purpose: The purpose of this study was to compare the effect of two types of cervical collars (Philadelphia and Miami-J) on pulmonary function and ventilation in healthy volunteers through spirometry, peak flow meter, and capnograph.

Method: Initially, subjects were randomized into two groups in which the sequence of collars' fixation was reversed. Afterward, we assessed the pulmonary parameters without a cervical collar in all participants. Each group underwent two additional test conditions, including measurements after wearing a Philadelphia and Miami-J cervical collar. In any case, we took the measurements half an hour after the collar fixation.

Results: The mean age of participants was 48.34 ± 1.35 years. Following either type of collars application, there was a statistically significant decrease in FEV1, FEV1/FVC, FEF25-75%, and PEF (p < .001). However, FVC was not significantly changed (p = .157).

Conclusion: In summary, we noted a statistically significant expiratory flow obstruction after both the Philadelphia and Miami-J cervical collar. These changes were not clinically significant in healthy volunteers, albeit may have ramifications in patients with pre-existing respiratory compromise.

Keywords: Cervical collar; Miami J; Philadelphia; Pulmonary function; Spirometry; Ventilation.

Publication types

  • Comparative Study

MeSH terms

  • Braces / adverse effects*
  • Cervical Vertebrae
  • Female
  • Healthy Volunteers
  • Humans
  • Male
  • Middle Aged
  • Neck
  • Prospective Studies
  • Pulmonary Ventilation*
  • Single-Blind Method
  • Spirometry