The impact of intensive care strain on patients' outcomes-a multinational observational cohort (UNITE-COVID) study

Intensive care unit (ICU) strain is associated with increased mortality. Most strain metrics focus on 'simple' measures such as bed occupancy or admission rates. There is limited data on mitigation strategies, such as procedure teams or staff well-being services on strain, or the impact of increased patient-to-nurse ratios and non-ICU trained nurses working in ICU.

Using the multi-national UNITE-COVID study, collecting data from ICUs on their day of peak bed occupancy in two periods (2020 and 2021) of the COVID-19 pandemic, we evaluated metrics of strain (Bed occupancy, patient: nurse ratio, use of non-ICU staff and shortages of consumables) and potential mitigators (procedural support teams and staff well-being interventions). We examined how these related to outcomes (mortality, complications, length of stay).

In both epochs, ICUs experienced significant strain, with ICU bed expansion to 133% and 163% respectively, whilst patient-to-nurse ratios increased by 0.4 and 0.3. Consumable shortages were widespread in 2020. Mortality was inversely correlated with staff well-being interventions in both epochs. Complications were inversely correlated with procedure support teams, and positively correlated with staffing ratios. In regression models, pressure sores were reduced in presence of support teams (p = 0.004) and increased with increasing patients per nurse (p = 0.05) whilst unplanned extubations were related to non-ICU trained staff working in ICU(p = 0.02).

COVID-19 induced ICU strain had effects beyond mortality, including increases in complications. Staff pressure and lack of ICU training were related to specific complications, whilst support teams and well-being interventions were associated with improved outcomes.