Volume-outcome relationships for tracheostomies in Australia and New Zealand Intensive Care Units: A registry-based retrospective study

Objective: It is unknown whether a volume-outcome relationship exists for patients who receive tracheostomy in the intensive care unit (ICU) as has been observed in other healthcare settings. This study aimed to determine the average number of tracheostomies performed per intensivist per ICU in Australia and New Zealand and associations with case fatality. Design: A retrospective cohort study of adult ICU admissions was conducted. Setting: Data from the Australia and New Zealand Intensive Care Society Adult Patient Database and Critical care resources registry were linked and analysed over the time period extending from 01 January 2018 to 31 March 2023. Participants: The study population included adults (aged >= 18 years) admitted to Australia and New Zealand ICUs who received tracheostomy. Intervention: No intervention was reported. Main outcome measures: The primary exposure variable was tracheostomies per intensivist (TPIs), which was calculated as (the number of patients who had tracheostomy inserted during their ICU admission)/(the total number of intensivists), for each site for each financial year. Results: There were 9318 patients from 172 ICUs over a 5-year period, from January 2018 to March 2023, who received tracheostomies and were included in this analysis. The median TPI value was 3.1 (interquartile range: 1.9-4.3). Raw case fatality in the total cohort was 13.7% (1280/9318). The lowest adjusted risk of death (8.5%, 95% confidence interval: 3.63%-13.36%) was observed when the TPI value was equal to 10.3, with higher risk of death observed at lower values of TPI. Conclusions: A volume-outcome relationship was observed between TPI value and hospital case fatality, with lower case fatality at higher TPI values across the entire range of TPI. (c) 2025 The Authors. Published by Elsevier B.V. on behalf of College of Intensive Care Medicine of Australia and New Zealand. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).