End-Tidal Carbon Dioxide Monitoring for Spontaneous Pneumothorax

Gyeong Min Lee; Yong Won Kim; Sanghun Lee; Han Ho Do; Jun Seok Seo; Jeong Hun Lee

doi:10.1155/2021/9976543

End-Tidal Carbon Dioxide Monitoring for Spontaneous Pneumothorax

Emerg Med Int. 2021 Jun 14:2021:9976543. doi: 10.1155/2021/9976543. eCollection 2021.

Authors

Gyeong Min Lee^{1

2}, Yong Won Kim^{1

2}, Sanghun Lee^{1

2}, Han Ho Do¹, Jun Seok Seo¹, Jeong Hun Lee¹

Affiliations

¹ Department of Emergency Medicine, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Republic of Korea.
² Department of Emergency Medicine, Kangwon National University College of Medicine, Chuncheon, Republic of Korea.

Abstract

Background: Spontaneous pneumothorax should be classified as primary spontaneous pneumothorax (PSP) or secondary spontaneous pneumothorax (SSP) because treatment strategies may differ depending on underlying lung conditions and clinical course. The pulmonary dysfunction can lead to changes in end-tidal carbon dioxide (ETCO₂). The aim of this study was to investigate the difference in ETCO₂ between PSP and SSP.

Methods: This retrospective observational study included adult patients diagnosed with spontaneous pneumothorax in the emergency room from April 2019 to September 2020. We divided patients into PSP and SSP groups and compared ETCO₂ variables between the two groups.

Results: There were 33 (66%) patients in the PSP group and 17 (34%) patients in the SSP group. Initial ETCO₂ was lower in the SSP group than in the PSP group (30 (23-33) vs. 35 (33-38) mmHg, p=0.002). Multivariate analysis revealed that respiratory gas associated with SSP was initial ETCO₂ (OR: 0.824; 95% CI: 0.697-0.974, p=0.023). The optimal cutoff for initial ETCO₂ to detection of SSP was 32 mmHg (area under curve, 0.754), with 76.5% sensitivity and 72.7% specificity.

Conclusion: ETCO₂ monitoring is a reliable noninvasive indicator of differentiating between PSP and SSP. Initial ETCO₂ lower than 32 mmHg is a predictor of SSP.