End tidal carbon dioxide monitoring in acute asthma: a prospective pilot study in emergency department patients. (December 2019)

• Record Type: Journal Article
• Authors: Truchot, Jennifer; Gayet, Albéric-Rembrandt; Philippon, Anne-Laure; Chauvin, Anthony; Malka, Johanna; Vicaut, Eric; Plaisance, Patrick
• Is Part Of: European journal of emergency medicine. Volume 26:Number 6(2019)
• Publication Date: 2019-12
• Subjects: asthma -- capnography -- end tidal carbon dioxide -- monitoring and emergency medicine; Emergency medicine -- Europe -- Periodicals; Medical emergencies -- Europe -- Periodicals; Emergency medical services -- Europe -- Periodicals; Emergencies -- Europe -- Periodicals; Emergency Medical Services -- Europe -- Periodicals; Emergency Medicine -- Europe -- periodicals; 616.025
• DOI: 10.1097/MEJ.0000000000000581
• Languages: English
• ISSNs: 0969-9546

Abstract

Abstract : The peak expiratory flow rate (PEFR) is the gold standard for monitoring asthmatic patients. However, its measurement requires understanding and active participation. End tidal carbon dioxide (EtCO2 ) may be considered an accurate surrogate for PaCO2, a severity marker in acute asthma. We studied the use of EtCO2 as a monitoring tool in acute asthma. Patients and methods: This was a prospective study that included consecutive patients admitted to our emergency department for acute asthma exacerbation. Data were collected at first medical contact (T0) and after 1 h of treatment (T60). The primary endpoint was the change in EtCO2 ; the secondary endpoints included changes in the EtCO2 Q angle value, plateau T time, and change in EtCO2 values for the patients with a PEFR ratio less than 50% after treatment. Results: Fifty-five patients were included and 36 waveforms were analysed. The mean age was 37 years and 26 (47%) were women. The median initial PEFR was 200 [interquartile range (IQR): 150–240]; the median EtCO2 at T0 and T60 was 35 (IQR: 30–38) and 34 (IQR: 29–37). There was no significant change in EtCO2 after treatment. There was no significant change in the Q angle and the T time after treatment. At T60, 20 (36%) patients had a PEFR ratio less than 50%. Change in EtCO2 from T60 to T0 was associated with a PEFR ratio less than 50%. Conclusion: After 1 h of treatment, there was no significant change in EtCO2 . A decrease in EtCO2 seems to be associated with a higher risk of PEFR ratio less than 50% after treatment.