@article {Hukins00041-2019, author = {Craig Hukins and Michelle Murphy and Timothy Edwards}, title = {Dose{\textendash}response characteristics of noninvasive ventilation in acute respiratory failure}, volume = {6}, number = {1}, elocation-id = {00041-2019}, year = {2020}, doi = {10.1183/23120541.00041-2019}, publisher = {European Respiratory Society}, abstract = {Acute noninvasive ventilation (NIV) is a well-established therapy for acute respiratory failure but the dose{\textendash}response characteristics of this therapy have not been defined. The aim of this study was to define this dose{\textendash}response relationship.This study was a retrospective review of patients receiving NIV for acute respiratory failure in a tertiary hospital respiratory high-dependency unit between July 2012 and June 2017. Mask-on time (rather than the period that NIV was in use) as the {\textquotedblleft}dose{\textquotedblright} was compared with hospital survival as the {\textquotedblleft}response{\textquotedblright}.654 patients were included, 594 (91\%) with hypercapnic respiratory failure (HCRF). NIV was used for a median (interquartile range (IQR)) duration of 2.74 (1.51{\textendash}4.73) days and median (IQR) mask-on time was 34 (18{\textendash}60) h (56.1\% (41.2{\textendash}69.5\%) of treatment time). There was evidence of a dose{\textendash}response relationship in the HCRF group up to a ceiling of 24 h mask-on time, but not in the hypoxaemic respiratory failure (HRF) group. There was a difference in survival with as little as 2 h mask-on time (92\% compared with 73\%; p\<0.001). Patients requiring NIV for 80{\textendash}100\% of therapy time had lower survival.We conclude that there is evidence of a dose{\textendash}response relationship between cumulative NIV usage (mask-on time) and survival from as little as 2 h to a ceiling of \~{}24 h in HCRF, but not in HRF.Acute NIV in respiratory failure has a dose{\textendash}response effect on survival from as little as 2 h of therapy http://bit.ly/2okErQZ}, URL = {https://openres.ersjournals.com/content/6/1/00041-2019}, eprint = {https://openres.ersjournals.com/content/6/1/00041-2019.full.pdf}, journal = {ERJ Open Research} }