Zealand Intensive Care Society Research Articles

Sustainability-national and international initiatives in intensive care and emergency medicine

Climate change with global warming, natural disasters, species extinction and soil erosion is doubly relevant for medicine: On the one hand, heat waves, floods and other natural disasters lead to new disease patterns to which healthcare systems must adapt. On the other hand, the global healthcare system itself contributes to these effects, as it is estimated that the CO2 footprint of all healthcare facilities accounts for around 5% of global greenhouse gas emissions. National and international initiatives to promote sustainability concepts in intensive care and emergency medicine. Research on homepages of national and international (specialist) societies dealing with intensive and emergency care medicine and corresponding PubMed search (sustainability and climate change and emergency or intensive care medicine). Six of the 12national specialist societies surveyed have taken initiatives on sustainability, notable among them the initiative of Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF) for anew registration of the S1guideline "Sustainability in intensive care and emergency medicine". On the international scene, the activities of the Australian and New Zealand Intensive Care Society (ANZICS) with numerous publications on the topic of sustainability in intensive care medicine and the practical guide "Abeginners guide to sustainability in intensive care medicine" as well as the European Society of Anaesthesiology and Intensive Care (ESAIC) with aconsensus paper on sustainability should be highlighted. At the national level, initiatives on sustainability (guidelines, working groups, forums) are emerging and are attracting increasing attention and activity. The umbrella organization of German Intensive Care Medicine, the Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin (DIVI), has so far shown no (discernible) activity; there is an urgent need for action here, and health policy and the German Medical Association should also become (even) more involved in reducing the CO2 footprint in the healthcare sector. Internationally, there are anumber of societies and institutions that are promoting the topic of "sustainability", although astronger focus on the area of intensive care and emergency medicine would also be desirable here.

Outcomes for people admitted to Australian and New Zealand intensive care units with primary, exacerbating, or incidental SARS-CoV-2 infections, 2022-23: a retrospective analysis of ANZICS data.

To compare in-hospital mortality and intensive care unit (ICU) length of stay for people admitted to Australian and New Zealand ICUs during 2022-23 with coronavirus disease 2019 (COVID-19) pneumonitis, incidental or exacerbating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, or without SAR-CoV-2 infections. Retrospective cohort study; analysis of Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database data. Adults (16 years or older) admitted to participating ICUs in Australia or New Zealand, 1 January 2022- 30 June 2023. The primary outcome was in-hospital mortality, the secondary outcome ICU length of stay, each by SARS-CoV-2 infection attribution classification: primary COVID-19; exacerbating SARS-CoV-2 infection (SARS-CoV-2 infection was a contributing factor to the primary cause of ICU admission); incidental SARS-CoV-2 infections (SARS-CoV-2 infection detected during ICU admission but did not contribute to admission diagnosis); no SARS-CoV-2 infection. A total of 207 684 adults were admitted to 195 Australian and New Zealand ICUs during 2022-23; 2674 people (1.3%) had incidental SARS-CoV-2 infections, 4923 (2.4%) exacerbating infections, and 3620 (1.7%) primary COVID-19. Unadjusted in-hospital mortality for people with incidental SARS-CoV-2 infections (288 deaths, 10.8%) was lower than for those with exacerbating infections (928 deaths, 18.8%) or primary COVID-19 (830 deaths, 22.9%), but higher than for patients without SARS-CoV-2 infections (15 486 deaths, 7.9%). After adjusting for illness severity, frailty, geographic region, and type of hospital, mortality was higher for patients with incidental SARS-CoV-2 infections (adjusted odds ratio [aOR], 1.28; 95% confidence interval [CI], 1.10-1.50), exacerbating infections (aOR, 1.35; 95% CI, 1.22-1.48), or primary COVID-19 (aOR, 2.54; 95% CI, 2.30-2.81) than for patients without SARS-CoV-2 infections. After adjusting for diagnosis and illness severity, ICU stays were longer for people with incidental (mean difference, 3.3 hours; 95% CI, 2.4-4.2 hours) or exacerbating infections (0.8 hours; 95% CI, 0.2-1.5 hours) than for those without SARS-CoV-2 infections. Risk-adjusted in-hospital mortality and ICU length of stay are higher for people admitted to intensive care who have concomitant SARS-CoV-2 infections than for people who do not.

Persistent Critical Illness and Long-Term Outcomes in Patients With COVID-19: A Multicenter Retrospective Cohort Study.

A nontrivial number of patients in ICUs experience persistent critical illness (PerCI), a phenomenon in which features of the ICU course more consistently predict mortality than the initial indication for admission. We aimed to describe PerCI among patients with critical illness caused by COVID-19, and these patients' short- and long-term outcomes. Multicenter retrospective cohort study. Australian and New Zealand Intensive Care Society Adult Patient Database of 114 Australian ICUs between January 1, 2020, and March 31, 2022. Patients 16 years old or older with COVID-19, and a documented ICU length of stay. The presence of PerCI, defined as an ICU length of stay greater than or equal to 10 days. We compared the survival time up to 2 years from ICU admission using time-varying robust-variance estimated Cox proportional hazards models. We further investigated the impact of PerCI in subgroups of patients, stratifying based on whether they survived their initial hospitalization. We included 4961 patients in the final analysis, and 882 patients (17.8%) had PerCI. ICU mortality was 23.4% in patients with PerCI and 6.5% in those without PerCI. Patients with PerCI had lower 2-year (70.9% [95% CI, 67.9-73.9%] vs. 86.1% [95% CI, 85.0-87.1%]; p < 0.001) survival rates compared with patients without PerCI. Patients with PerCI had higher mortality (adjusted hazards ratio: 1.734; 95% CI, 1.388-2.168); this was consistent across several sensitivity analyses. When analyzed as a nonlinear predictor, the hazards of mortality were inconsistent up until 10 days, before plateauing. In this multicenter retrospective observational study patients with PerCI tended to have poorer short-term and long-term outcomes. However, the hazards of mortality plateaued beyond the first 10 days of ICU stay. Further studies should investigate predictors of developing PerCI, to better prognosticate long-term outcomes.

Impact of frailty on long-term survival in patients discharged alive from hospital after an ICU admission with COVID-19

ObjectiveThough frailty is associated with mortality, its impact on long-term survival after an ICU admission with COVID-19 is unclear. We aimed to investigate the association between frailty and long-term survival in patients after an ICU admission with COVID-19. Design, Setting and ParticipantsThis registry-based multicentre, retrospective, cohort study included all patients ≥16 years discharged alive from the hospital following an ICU admission with COVID-19 and documented clinical frailty scale (CFS). Data from 118 ICUs between 01/01/2020 through 31/12/2020 in New Zealand and 31/12/2021 in Australia were reported in the Australian and New Zealand Intensive Care Society Adult Patient Database. The patients were categorised as ‘not frail’ (CFS 1-3), ‘mildly frail’ (CFS 4-5) and ‘moderately-to-severely frail’ (CFS 6-8). Main Outcome MeasuresThe primary outcome was survival time up to two years, which we analysed using Cox regression models. ResultsWe included 4028 patients with COVID-19 in the final analysis. ‘Moderately-to-severely frail’ patients were older (66.6 [56.3–75.8] vs. 69.9 [60.3–78.1]; p < 0.001) than those without frailty (median [interquartile range] 53.0 [40.1–64.6]), had higher sequential organ failure assessment scores (p < 0.001), and less likely to receive mechanical ventilation (p < 0.001) than patients without frailty or mild frailty. After adjusting for confounders, patients with mild frailty (adjusted hazards ratio: 2.31, 95%-CI: 1.75–3.05) and moderate-to-severe frailty (adjusted hazards ratio: 2.54, 95%-CI: 1.89–3.42) had higher mortality rates than those without frailty. ConclusionsFrailty was independently associated with shorter survival times to two years in patients with severe COVID-19 in ANZ following hospital discharge. Recognising frailty provides individualised patient intervention in those with frailty admitted to ICUs with severe COVID-19. Clinical trial registrationNot applicable.

Epidemiology of Intensive Care Patients Classified as a Third Sex in Australia and New Zealand

BackgroundPatient sex affects treatment and outcomes in critical illness. Previous studies of sex differences in critical illness compared female and male patients. In this study we describe the group of patients classified as a third sex admitted to intensive care units (ICUs) in Australia and New Zealand. Research questionWhat are the admission characteristics and outcomes of ICU patients classified as belonging to a third sex group, compared to patients classified female or male? Study design and methodsRetrospective observational study of admissions to 200 ICUs, recorded in the Australia and New Zealand Intensive Care Society’s Adult Patient Database 2018–2022. We undertook mixed effect logistic regression to compare hospital mortality across the sex groups, adjusted for illness severity, diagnosis, treatment limitation, year and hospital. ResultsWe examined 892,161 admissions, of whom 525 (0.06%) were classified as third sex. Patients classified as third sex were represented across all diagnostic categories, jurisdictions, and hospital types. On average, they were younger than the groups classified as female (59.2+/-20.0 years vs 61.3+/-18.4 years, p=0.02) or male (63.2+/-16.7 years, p<0.001). Patients classified as third sex were more likely to be admitted following orthopedic surgery (10.1% third sex admissions (95% CI 7.7-13.0%) vs 6.2% female (95% CI 6.1-6.3%); 4.8% male (95% CI 4.7-4.9%)) and drug overdose (8.8% third sex admissions (95% CI 6.5-11.5%) vs 4.2% female (95% CI 4.1-4.2%); 3.1% male (95% CI 3.0-3.1%)). There was no difference in the adjusted hospital mortality of patients classified as third sex compared to the other groups. InterpretationPatients classified as third sex composed a small minority of adult ICU patients. This group had a different diagnostic casemix, but similar outcomes, to the groups classified as female or male. Further characterizing a third sex group will require improved processes for recording sex and gender in health records.

Frailty and long-term survival among patients in Australian intensive care units with metastatic cancer (FRAIL-CANCER study): a retrospective registry-based cohort study

Recent advances in cancer therapeutics have improved outcomes, resulting in increasing candidacy of patients with metastatic cancer being admitted to intensive care units (ICUs). A large proportion of patients also have frailty, predisposing them to poor outcomes, yet the literature reporting on this is scarce. We aimed to assess the impact of frailty on survival in patients with metastatic cancer admitted to the ICU. In this retrospective registry-based cohort study, we used data from the Australia and New Zealand Intensive Care Society Adult Patient (age ≥16 years) database to identify patients with advanced (solid and haematological cancer) and a documented Clinical Frailty scale (CFS) admitted to 166 Australian ICUs. Patients without metastatic cancer were excluded. We analysed the effect of frailty (CFS 5-8) on long-term survival, and how this effect changed in specific subgroups (cancer subtypes, age [<65 years or ≥65 years], and those who survived hospitalisation). Because estimates tend to cluster within centres and vary between them, we used Cox proportional hazards regression models with robust sandwich variance estimators to assess the effect of frailty on survival time up to 4 years after ICU admission between groups. Between Jan 1, 2018, and March 31, 2022, 30 026 patients were eligible, and after exclusions 21 174 patients were included in the analysis; of these, 6806 (32·1%) had frailty, and 11 662 (55·1%) were male, 9489 (44·8%) were female, and 23 (0·1%) were intersex or self-reported indeterminate sex. The overall survival was lower for patients with frailty at 4 years compared with patients without frailty (29·5% vs 10·9%; p<0·0001). Frailty was associated with shorter 4-year survival times (adjusted hazard ratio 1·52 [95% CI 1·43-1·60]), and this effect was seen across all cancer subtypes. Frailty was associated with shorter survival times in patients younger than 65 years (1·66 [1·51-1·83]) and aged 65 years or older (1·40 [1·38-1·56]), but its effects were larger in patients younger than 65 years (pinteraction<0·0001). Frailty was also associated with shorter survival times in patients who survived hospitalisation (1·49 [1·40-1·59]). In patients with metastatic cancer admitted to the ICU, frailty was associated with poorer long-term survival. Patients with frailty might benefit from a goal-concordant time-limited trial in the ICU and will need suitable post-intensive care supportive management. None.

The impact of body mass index on long-term survival after ICU admission due to COVID-19: A retrospective multicentre study

ObjectiveThe impact of obesity on long-term survival after intensive care unit (ICU) admission with severe coronavirus disease 2019 (COVID-19) is unclear. We aimed to quantify the impact of obesity on time to death up to two years in patients admitted to Australian and New Zealand ICUs. DesignRetrospective multicentre study. Setting92 ICUs between 1st January 2020 through to 31st December 2020 in New Zealand and 31st March 2022 in Australia with COVID-19, reported in the Australian and New Zealand Intensive Care Society adult patient database. ParticipantsAll patients with documented height and weight to estimate the body mass index (BMI) were included. Obesity was classified patients according to the World Health Organization recommendations. Interventions and main outcome measuresThe primary outcome was survival time up to two years after ICU admission. The effect of obesity on time to death was assessed using a Cox proportional hazards model. Confounders were acute illness severity, sex, frailty, hospital type and jurisdiction for all patients. ResultsWe examined 2,931 patients; the median BMI was 30.2 (IQR 25.6–36.0) kg/m2. Patients with a BMI ≥30 kg/m2 were younger (median [IQR] age 57.7 [46.2–69.0] vs. 63.0 [50.0–73.6]; p < 0.001) than those with a BMI <30 kg/m2. Most patients (76.6%; 2,244/2,931) were discharged alive after ICU admission. The mortality at two years was highest for BMI categories <18.5 kg/m2 (35.4%) and 18.5–24.9 kg/m2 (31.1%), while lowest for BMI ≥40 kg/m2 (14.5%). After adjusting for confounders and with BMI 18.5–24.9 kg/m2 category as a reference, only the BMI ≥40 kg/m2 category patients had improved survival up to 2 years (hazard ratio = 0.51; 95%CI: 0.34–0.76). ConclusionsThe obesity paradox appears to exist beyond hospital discharge in critically ill patients with COVID-19 admitted in Australian and New Zealand ICUs. A BMI ≥40 kg/m2 was associated with a higher survival time of up to two years.

Modelling of intensive care unit (ICU) length of stay as a quality measure: a problematic exercise

BackgroundIntensive care unit (ICU) length of stay (LOS) and the risk adjusted equivalent (RALOS) have been used as quality metrics. The latter measures entail either ratio or difference formulations or ICU random effects (RE), which have not been previously compared.MethodsFrom calendar year 2016 data of an adult ICU registry-database (Australia & New Zealand Intensive Care Society (ANZICS) CORE), LOS predictive models were established using linear (LMM) and generalised linear (GLMM) mixed models. Model fixed effects quality-metric formulations were estimated as RALOSR for LMM (geometric mean derived from log(ICU LOS)) and GLMM (day) and observed minus expected ICU LOS (OMELOS from GLMM). Metric confidence intervals (95%CI) were estimated by bootstrapping; random effects (RE) were predicted for LMM and GLMM. Forest-plot displays of ranked quality-metric point-estimates (95%CI) were generated for ICU hospital classifications (metropolitan, private, rural/regional, and tertiary). Robust rank confidence sets (point estimate and 95%CI), both marginal (pertaining to a singular ICU) and simultaneous (pertaining to all ICU differences), were established.ResultsThe ICU cohort was of 94,361 patients from 125 ICUs (metropolitan 16.9%, private 32.8%, rural/regional 6.4%, tertiary 43.8%). Age (mean, SD) was 61.7 (17.5) years; 58.3% were male; APACHE III severity-of-illness score 54.6 (25.7); ICU annual patient volume 1192 (702) and ICU LOS 3.2 (4.9). There was no concordance of ICU ranked model predictions, GLMM versus LMM, nor for the quality metrics used, RALOSR, OMELOS and site-specific RE for each of the ICU hospital classifications. Furthermore, there was no concordance between ICU ranking confidence sets, marginal and simultaneous for models or quality metrics.ConclusionsInference regarding adjusted ICU LOS was dependent upon the statistical estimator and the quality index used to quantify any LOS differences across ICUs. That is, there was no “one best model”; thus, ICU “performance” is determined by model choice and any rankings thereupon should be circumspect.

Measuring the Impact of ICU Strain on Mortality, After-Hours Discharge, Discharge Delay, Interhospital Transfer, and Readmission in Australia With the Activity Index.

ICU resource strain leads to adverse patient outcomes. Simple, well-validated measures of ICU strain are lacking. Our objective was to assess whether the "Activity index," an indicator developed during the COVID-19 pandemic, was a valid measure of ICU strain. Retrospective national registry-based cohort study. One hundred seventy-five public and private hospitals in Australia (June 2020 through March 2022). Two hundred seventy-seven thousand seven hundred thirty-seven adult ICU patients. None. Data from the Australian and New Zealand Intensive Care Society Adult Patient Database were matched to the Critical Health Resources Information System. The mean daily Activity index of each ICU (census total of "patients with 1:1 nursing" + "invasive ventilation" + "renal replacement" + "extracorporeal membrane oxygenation" + "active COVID-19," divided by total staffed ICU beds) during the patient's stay in the ICU was calculated. Patients were categorized as being in the ICU during very quiet (Activity index < 0.1), quiet (0.1 to < 0.6), intermediate (0.6 to < 1.1), busy (1.1 to < 1.6), or very busy time-periods (≥ 1.6). The primary outcome was in-hospital mortality. Secondary outcomes included after-hours discharge from the ICU, readmission to the ICU, interhospital transfer to another ICU, and delay in discharge from the ICU. Median Activity index was 0.87 (interquartile range, 0.40-1.24). Nineteen thousand one hundred seventy-seven patients died (6.9%). In-hospital mortality ranged from 2.4% during very quiet to 10.9% during very busy time-periods. After adjusting for confounders, being in an ICU during time-periods with higher Activity indices, was associated with an increased risk of in-hospital mortality (odds ratio [OR], 1.49; 99% CI, 1.38-1.60), after-hours discharge (OR, 1.27; 99% CI, 1.21-1.34), readmission (OR, 1.18; 99% CI, 1.09-1.28), interhospital transfer (OR, 1.92; 99% CI, 1.72-2.15), and less delay in ICU discharge (OR, 0.58; 99% CI, 0.55-0.62): findings consistent with ICU strain. The Activity index is a simple and valid measure that identifies ICUs in which increasing strain leads to progressively worse patient outcomes.

How often are infusion sets for central venous catheters changed in Australian and New Zealand Intensive Care Units? A point prevalence survey

BackgroundInfusion sets (comprising the tubing, measuring burettes, fluid containers, transducers) that are connected to invasive vascular devices are changed on a regular basis in an effort to reduce bacterial colonisation and bloodstream infection. There is a balance between reducing infection and creating unnecessary waste. Current evidence suggests that for central venous catheters (CVCs), changing infusion sets at 7 days does not increase infection risks. ObjectivesThe objective of this study was to describe the current unit guidelines in Australian and New Zealand intensive care units (ICUs) for changing infusion sets for CVCs. Methodsprospective cross-sectional point prevalence study, as a part of the 2021 Australian and New Zealand Intensive Care Society Point Prevalence Program. ParticipantsAustralia and New Zealand (ANZ) adult ICUs and their patients on the day of the study. ResultsData were collected from 51 ICUs across ANZ. One-third of these (16/49) ICUs had a guideline that specified a 7-day replacement period, with the rest having a more frequent replacement period. ConclusionMost ICUs participating in this survey had policies to change their CVC infusion tubing in 3–4 days, and recent high-level evidence supports an update to extend this to 7 days. There remains work to be done to spread this evidence to ANZ ICUs and improve environmental sustainability initiatives.

Mortality data from omission of early thromboprophylaxis in critically ill patients highlights the importance of an individualised diagnosis-related approach

BackgroundVenous thromboembolism (VTE) prophylaxis is effective in reducing VTE events, however, its impact on mortality is unclear. We examined the association between omission of VTE prophylaxis within the first 24 h after intensive care unit (ICU) admission and hospital mortality.MethodsRetrospective analysis of prospectively collected data from the Australian New Zealand Intensive Care Society Adult Patient Database. Data were obtained for adult admissions between 2009 and 2020. Mixed effects logistic regression models were used to evaluate the association between omission of early VTE prophylaxis and hospital mortality.ResultsOf the 1,465,020 ICU admissions, 107,486 (7.3%) did not receive any form of VTE prophylaxis within the first 24 h after ICU admission without documented contraindication. Omission of early VTE prophylaxis was independently associated with 35% increased odds of in-hospital mortality (odds ratios (OR): 1.35; 95% CI: 1.31–1.41). The associations between omission of early VTE prophylaxis and mortality varied by admission diagnosis. In patients diagnosed with stroke (OR: 1.26, 95% CI: 1.05–1.52), cardiac arrest (OR: 1.85, 95% CI: 1.65–2.07) or intracerebral haemorrhage (OR: 1.48, 95% CI: 1.19–1.84), omission of VTE prophylaxis was associated with increased risk of mortality, but not in patients diagnosed with subarachnoid haemorrhage or head injury.ConclusionsOmission of VTE prophylaxis within the first 24 h after ICU admission was independently associated with increased risk of mortality that varied by admission diagnosis. Consideration of early thromboprophylaxis may be required for patients with stroke, cardiac arrest and intracerebral haemorrhage but not in those with subarachnoid haemorrhage or head injury. The findings highlight the importance of individualised diagnosis-related thromboprophylaxis benefit-harm assessments.

Mortality among people admitted to Australian intensive care units for reasons other than COVID-19 during the COVID-19 pandemic: a retrospective cohort study.

To investigate in-hospital mortality among people admitted to Australian intensive care units (ICUs) with conditions other than coronavirus disease 2019 (COVID-19) during the COVID-19 pandemic. National, multicentre, retrospective cohort study; analysis of data in the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation (ANZICS CORE) Adult Patient Database. Adults (16 years or older) without COVID-19 admitted to Australian ICUs, 1 January 2016 - 30 June 2022. All-cause in-hospital mortality, unadjusted and relative to the January 2016 value, adjusted for illness severity (Australian and New Zealand Risk of Death [ANZROD] and hospital type), with ICU as a random effect. Points of change in mortality trends (breakpoints) were identified by segmental regression analysis. Data for 950 489 eligible admissions to 186 ICUs were available. In-hospital mortality declined steadily from January 2016 to March 2021 by 0.3% per month (P < 0.001; March 2021 v January 2016: adjusted odds ratio [aOR], 0.70; 95% confidence interval [CI], 0.62-0.80), but rose by 1.4% per month during March 2021 - June2022 (P < 0.001; June 2022 v January 2016: aOR, 1.03; 95% CI, 0.90-1.17). The rise in mortality continued after the number of COVID-19-related ICU admissions had declined; mortality increased in jurisdictions with lower as well as in those with higher numbers of COVID-19-related ICU admissions. The rise in in-hospital mortality among people admitted to Australian ICUs with conditions other than COVID-19 from March 2021 reversed the improvement of the preceding five years. Changes to health service delivery during the pandemic and their consequences should be investigated further.

Thirty years of ANZICS CORE: A clinical quality success story

In 2023, the Australian and New Zealand Intensive Care Society (ANZICS) Registry run by the Centre for Outcomes and Resources Evaluation (CORE) turns 30 years old. It began with the Adult Patient Database, the Australian and New Zealand Paediatric Intensive Care Registry, and the Critical Care Resources Registry, and it now includes Central Line Associated Bloodstream Infections Registry, the Extra-Corporeal Membrane Oxygenation Database, and the Critical Health Resources Information System. The ANZICS Registry provides comparative case-mix reports, risk-adjusted clinical outcomes, process measures, and quality of care indicators to over 200 intensive care units describing more than 200 000 adult and paediatric admissions annually. The ANZICS CORE outlier management program has been a major contributor to the improved patient outcomes and provided significant cost savings to the healthcare sector. Over 200 peer-reviewed papers have been published using ANZICS Registry data. The ANZICS Registry was a vital source of information during the COVID-19 pandemic. Upcoming developments include reporting of long-term survival and patient-reported outcome and experience measures.

Association Between Preexisting Mental Health Disorders and Adverse Outcomes in Adult Intensive Care Patients: A Data Linkage Study.

Mental illness is known to adversely affect the physical health of patients in primary and acute care settings; however, its impact on critically ill patients is less well studied. This study aimed to determine the prevalence, characteristics, and outcomes of patients admitted to the ICU with a preexisting mental health disorder. A multicenter, retrospective cohort study using linked data from electronic ICU clinical progress notes and the Australia and New Zealand Intensive Care Society Adult Patient Database. All patients admitted to eight Australian adult ICUs in the calendar year 2019. Readmissions within the same hospitalization were excluded. None. Natural language processing techniques were used to classify preexisting mental health disorders in participants based on clinician documentation in electronic ICU clinical progress notes. Sixteen thousand two hundred twenty-eight patients (58% male) were included in the study, of which 5,044 (31.1%) had a documented preexisting mental health disorder. Affective disorders were the most common subtype occurring in 2,633 patients (16.2%), followed by anxiety disorders, occurring in 1,611 patients (9.9%). Mixed-effects regression modeling found patients with a preexisting mental health disorder stayed in ICU 13% longer than other patients (β-coefficient, 0.12; 95% CI, 0.10-0.15) and were more likely to experience invasive ventilation (odds ratio, 1.42; 95% CI, 1.30-1.56). Severity of illness and ICU mortality rates were similar in both groups. Patients with preexisting mental health disorders form a significant subgroup within the ICU. The presence of a preexisting mental health disorder is associated with greater ICU length of stay and higher rates of invasive ventilation, suggesting these patients may have a different clinical trajectory to patients with no mental health history. Further research is needed to better understand the reasons for these adverse outcomes and to develop interventions to better support these patients during and after ICU admission.

The relationship between nursing skill mix and severity of illness of patients admitted in Australian and New Zealand intensive care units

BackgroundCritically ill patients in the intensive care environment require an appropriate nursing workforce to improve quality of care and patient outcomes. However, limited information exists as to the relationship between severity of illness and nursing skill mix in the intensive care. ObjectiveThe aim of this study was to describe the variation in nursing skill mix across different hospital types and to determine if this was associated with severity of illness of critically ill patients admitted to adult intensive care units (ICUs) in Australia and New Zealand. Design & SettingA retrospective cohort study using the Australia and New Zealand Intensive Care Society Adult Patient Database (to provide information on patient demographics, severity of illness, and outcome) and the Critical Care Resources Registry (to provide information on annual nursing staffing levels and hospital type) from July 2014 to June 2020. Four hospital types (metropolitan, private, rural/regional, and tertiary) and three patient groups (elective surgical, emergency surgical, and medical) were examined. Main outcome measureThe main outcome measure was the proportion of critical care specialist registered nurses (RNs) expressed as a percentage of the full-time equivalent (FTE) of total RNs working within each ICU each year, as reported annually to the Critical Care Resources Registry. ResultsData were examined for 184 ICUs in Australia and New Zealand. During the 6-year study period, 770 747 patients were admitted to these ICUs. Across Australia and New Zealand, the median percentage of registered nursing FTE with a critical care qualification for each ICU (n = 184) was 59.1% (interquartile range [IQR] = 48.9–71.6). The percentage FTE of critical care specialist RNs was highest in private [63.7% (IQR = 52.6–78.2)] and tertiary ICUs [58.1% (IQR = 51.2–70.2)], followed by metropolitan ICUs [56.0% (IQR = 44.5–68.9)] with the lowest in rural/regional hospitals [55.9% (IQR = 44.9–70.0)]. In ICUs with higher percentage FTE of critical care specialist RNs, patients had higher severity of illness, most notably in tertiary and private ICUs. This relationship was persistent across all hospital types when examining subgroups of emergency surgical and medical patients and in multivariable analysis after adjusting for the type of hospital and relative percentage of each diagnostic group. ConclusionsIn Australian and New Zealand ICUs, the highest acuity patients are cared for by nursing teams with the highest percentage FTE of critical care specialist RNs. The Australian and New Zealand healthcare system has a critical care nursing workforce which scales to meet the acuity of ICU patients across Australia and New Zealand.

Projecting Future Climate Impact on National Australian Respiratory-Related Intensive Care Unit Demand.

A robust climate-health projection model has the potential to improve health care resource allocation. We aim to explore the relationship between Australian intensive care unit (ICU) demand and various measures of the long-lived large-scale climate and to develop a future nationwide climate-health projection model. We investigated patients admitted to ICUs in Australia between January 2003 and December 2019 who were exposed to long-lived large-scale combined climatic measures of temperature and humidity. We analysed the projected demand for respiratory-related ICU average length of stay (in days) per capita (ICUD/C) with four historical and one future projection dataset. These datasets included: i) Australian and New Zealand Intensive Care Society adult patient database, ii) Socioeconomic Data and Applications Center gridded global historical population, iii) Australian Bureau of Statistics national historical population, iv) Japanese 55-year Reanalysis historical climate (JRA55), and v) the fifth Coupled Model Inter-comparison Project future climate projections. 148,638 patients with respiratory issues required intensive care between 2003 and 2019. The annual growth in the population density-weighted wet-bulb-globe temperature-a combined measure of temperature and humidity-is strongly correlated with the annual per capita growth ICUD/C for respiratory-related conditions (r=0.771; p<0.001). This relationship was applied to develop a model projecting future respiratory-related ICU demand with three possible future Representative Concentration Pathways (RCP). RCP2.6 (lowest carbon emission climate scenario) showed only a 33.4% increase in Australian ICUD/C demand by 2090, while the RCP8.5 (highest carbon emission climate scenario) demonstrated almost two-fold higher demand (66.1%) than RCP2.6 by2090. The annual growth in population density-weighted wet-bulb-globe temperature correlates with the annual growth in Australian ICUD/C for respiratory-related conditions. A model based on possible future climate scenarios can be developed to predict changes in ICU demand in response to CO2 changes over the coming decades.

The prevalence of post-extubation dysphagia in critically ill adults: an Australian data linkage study

Objective: To define the prevalence of dysphagia after endotracheal intubation in critically ill adult patients. Design: A retrospective observational data linkage cohort study using the Australian and New Zealand Intensive Care Society Adult Patient Database and a mandatory government statewide health care administration database. Setting: Private and public intensive care units (ICUs) within Victoria, Australia. Participants: Adult patients who required endotracheal intubation for the purpose of mechanical ventilation within a Victorian ICU between July 2013 and June 2018. Main outcome measures: Presence of dysphagia, aspiration pneumonia, ICU length of stay, hospital length of stay, and cost per episode of care. Results: Endotracheal intubation in the ICU was required for 71 124 patient episodes across the study period. Dysphagia was coded in 7.3% (n = 5203) of those episodes. Patients with dysphagia required longer ICU (median, 154 [interquartile range (IQR), 78-259] v 53 [IQR, 27-107] hours; P < 0.001) and hospital admissions (median, 20 [IQR, 13-30] v 8 [IQR, 5-15] days; P < 0.001), were more likely to develop aspiration pneumonia (17.2% v 5.6%; odds ratio, 3.0; 95% CI, 2.8-3.2; P < 0.001), and the median health care expenditure increased by 93% per episode of care ($73 586 v $38 108; P < 0.001) compared with patients without dysphagia. Conclusions: Post-extubation dysphagia is associated with adverse patient and health care outcomes. Consideration should be given to strategies that support early identification of patients with dysphagia in the ICU to determine if these adverse outcomes can be reduced.

Association between frailty, delirium, and mortality in older critically ill patients: a binational registry study

BackgroundFrailty and delirium are prevalent among older adults admitted to the intensive care unit (ICU) and associated with adverse outcomes; however, their relationships have not been extensively explored. This study examined the association between frailty and mortality and length of hospital stay (LOS) in ICU patients, and whether the associations are mediated or modified by an episode of delirium.MethodsRetrospective analysis of data from the Australian New Zealand Intensive Care Society Adult Patient Database. A total of 149,320 patients aged 65 years or older admitted to 203 participating ICUs between 1 January 2017 and 31 December 2020 who had data for frailty and delirium were included in the analysis.ResultsA total of 41,719 (27.9%) older ICU patients were frail on admission, and 9,179 patients (6.1%) developed delirium during ICU admission. Frail patients had significantly higher odds of in-hospital mortality (OR: 2.15, 95% CI 2.05–2.25), episodes of delirium (OR: 1.86, 95% CI 1.77–1.95), and longer LOS (log-transformed mean difference (MD): 0.24, 95% CI 0.23–0.25). Acute delirium was associated with 32% increased odds of in-hospital mortality (OR: 1.32, 95% CI 1.23–1.43) and longer LOS (MD: 0.54, 95% CI 0.50–0.54). The odds ratios (95% CI) for in-hospital mortality were 1.37 (1.23–1.52), 2.14 (2.04–2.24) and 2.77 (2.51–3.05) for non-frail who developed delirium, frail without delirium, and frail and developed delirium during ICU admission, respectively. There was very small but statistically significant effect of frailty on in-hospital mortality (b for indirect effect: 0.00037, P < 0.001) and LOS (b for indirect effect: 0.019, P < 0.001) mediated through delirium.ConclusionBoth frailty and delirium independently increase the risk of in-hospital mortality and LOS. Acute delirium is more common in frail patients; however, it does not mediate or modify a clinically meaningful amount of the association between frailty and in-hospital mortality and LOS.

Twelve-month mortality outcomes for Indigenous and non-Indigenous people admitted to intensive care units in Australia: a registry-based data linkage study.

To compare longer term (12-month) mortality outcomes for Indigenous and non-Indigenous people admitted to intensive care units (ICUs) in Australia. Retrospective registry-based data linkage cohort study; analysis of all admissions of adults (16 years or older) to Australian ICUs, 1 January 2017 - 31 December 2019, as recorded in the Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD), linked using the SLK-581 key to National Death Index data. Unadjusted and adjusted mortality risk, censored at twelve months from the start of index ICU admission. Secondary outcomes were unadjusted and adjusted mortality twelve months from admission to the ICU. The APD recorded 330 712 eligible ICU admissions during 2017-2019 (65% of all ICU admissions registered), of which 11 322 were of Indigenous people (3.4%). Median age at admission was lower for Indigenous patients (51.2 [IQR, 36.7-63.6] years) than for non-Indigenous patients (66.5 [IQR, 52.7-76.1] years). Unadjusted mortality risk was similar for Indigenous and non-Indigenous patients (hazard ratio, 1.01; 95% CI, 0.97-1.06), but was higher for Indigenous patients after adjusting for age, admission diagnosis, illness severity, hospital type, jurisdiction, remoteness and socio-economic status (adjusted hazard ratio, 1.20; 95% CI, 1.14-1.27). Twelve-month mortality was higher for Indigenous than non-Indigenous patients (adjusted odds ratio, 1.24; 95% CI, 1.16-1.33). Twelve-month mortality outcomes are poorer for people admitted to ICUs in Australia than for the general population. Further, after adjusting for age and other factors, survival outcomes are poorer for Indigenous than non-Indigenous people admitted to ICUs. Critical illness may therefore contribute to shorter life expectancy among Indigenous Australians.

The impact of language barriers & interpreters on critical care patient outcomes

BackgroundIn a multicultural society, the impact of language proficiency and interpreter use on critical care patient outcomes is unknown. ObjectiveTo investigate the relationship between English language preference, requirement for an interpreter and in-hospital mortality amongst non-elective intensive care unit (ICU) patients. MethodAdult patients admitted to all 23 public ICUs within the state of Victoria, Australia from July 2007 to June 2018, were extracted from The Australian New Zealand Intensive Care Society Adult Patient Database. De-identified patient data was matched using probabilistic methods and statistical linkage keys to the Victorian Admitted Episodes Database. Patients were classified into one of three groups: ‘English preferred’, ‘English not preferred’ and ‘Interpreter required’. Results126,891 ICU admissions were analysed, of whom 3394 (3%) were in the ‘English not preferred’ group and 6355 (5%) in the ‘Interpreter required’ group. Compared to the ‘English preferred’, both the ‘English not preferred’ and ‘Interpreter required’ groups were older, had more co-morbidities and higher severity of illness scores. In-hospital mortality was 13.1% in the ‘English preferred’ group, 19.6% in the ‘English not preferred’ group and 16.7% in the ‘Interpreter required’ group. However, after adjusting for sex, severity of illness and socio-economic status, the ‘English not preferred’ group remained with a higher risk adjusted mortality (OR 1.21, 95%CI 1.07–1.36, P = 0.002), whereas the ‘Interpreter required’ group had a lower adjusted risk of mortality (OR 0.81, 95%CI 0.74–0.89, P < 0.001). ConclusionBeing identified as having a requirement for an interpreter was associated with improved outcomes for adults admitted to public hospital ICUs in Victoria. Interpreter services should be more readily available in the hospital setting. It is recommended that patients, family members and clinicians actively use interpreter services when English is not the preferred language of an ICU patient.