Thoracic gunshot wounds: alterations to pulmonary function and respiratory muscle strength.

BACKGROUND

The impact on respiratory function of gunshot injuries to the chest is unknown. The objective is to assess pulmonary function and respiratory muscle strength (RMS) in patients who have recently sustained an isolated gunshot injury to the chest.

METHODS

After institutional review board approval, patients with isolated gunshot injuries to the chest were prospectively identified. Study patients underwent pulmonary function testing and an assessment of RMS and gas exchange.

RESULTS

Ten male patients sustaining an isolated pulmonary gunshot wound were prospectively enrolled with a mean age of 29 years ± 10 years and mean Injury Severity Score of 15 ± 5. All patients had an associated pneumothorax (n = 1), hemothorax (n = 4), or a combination of both (n = 5). After removal of all thoracostomy tubes and before discharge [7.4 days ± 5.4 days (range, 2-21 days)], patients underwent respiratory function testing. Lung volume subdivisions were reduced by 25% to 60% of predicted and diffusion capacity by 37% with preservation of the normal ratio of diffusion capacity to alveolar volume. In the six subjects able to perform spirometry in seated and supine postures, forced vital capacity decreased by 20% when changing posture (p = 0.046). Arterial blood gas analysis showed significant reduction in the P(AO)₂/FIO₂ ratio (or increase in AaDO₂). Maximal respiratory pressures were severely reduced from predicted values, the maximal inspiratory pressure by 60% and the maximal expiratory pressure by 78%.

CONCLUSIONS

Lung volumes and RMS are decreased moderately to severely in patients who have sustained an isolated pulmonary gunshot wound. Expiratory muscle force generation is more severely affected than inspiratory muscle force. Further investigation of the long-term impact of these injuries on respiratory function is warranted.