Background Randomised control trial (RCT)-derived survival figures for acute exacerbation of chronic obstructive pulmonary disease admissions managed with non-invasive ventilation (NIV) have not been replicated in UK clinical audits. Subsequent guidelines have emphasised the need for timely NIV application.
Methods Data from the 2008 and 2014 national chronic obstructive pulmonary disease audits was used to analyse the association between time to NIV and mortality
Results 1032 patients received NIV in 2008, and 1612 in 2014. Overall mortality rates reduced between the audits from 24.9% in 2008 to 16.8% in 2014 but time to NIV lengthened. In 2014, 20.9% of patients received NIV within 60 min versus 24.9% in 2008 (p=0.001). The proportion of patients receiving NIV between 3 and 24 hours increased from 31.3% in 2008 to 39% in 2014 (p=0.001). Patients admitted with hypercapnic acidotic respiratory failure who received NIV within 3 hours had lower in-patient mortality than those who received NIV between 3 and 24 hours, 15.9% versus 18.4%, but this did not reach statistical significance (p=0.425), but acidotic patients receiving NIV >24 hours after admission had significantly higher mortality (28.9%, p=0.002). A second cohort admitted with hypercapnia but normal range pH, who developed later acidosis, had higher mortality (24.6%), compared with those acidotic on admission (18% p≤0.001) and an extremely high mortality when NIV was given >24 hours after admission (42.6%).
Conclusion Survival rates for those treated with NIV has improved between the two audits but remains lower than reported in RCTs. Patients who developed acidosis after admission and received NIV later in the hospital stay have even higher mortality and deserve further study and clinical attention.
- copd exacerbations
- non-invasive ventilation
- COPD epidemiology
- clinical epidemiology
- time to NIV
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Statistics from Altmetric.com
Contributors We confirm the authors have all contributed to this paper in the following ways: conception and design of the work: CMR, RS, MCS and AJ. Data collection: VM. Data analysis and interpretation: AJ, CMR, VM, RS and MCS. Drafting the article: AJ and CMR. Critical revision of the article: AJ, CMR, RS and MCS. Final approval of the version to be published: AJ, RS, VM, MCS and RS.
Funding The National COPD audit programme was funded by NHS England and the Welsh Government via the Healthcare Quality Improvement Partnership. However, no funding was received for the analysis and writing of this article.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This is analysis of audit data and research of clinical practice standards compared to national guidelines, therefore does not require REC approval.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.