Critical Care - Research Publications
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ItemThe Rapid Development of Virtual Care Tools in Response to COVID-19: Case Studies in Three Australian Health Services(JMIR PUBLICATIONS, INC, 2022-04)BACKGROUND: News of the impact of COVID-19 around the world delivered a brief opportunity for Australian health services to plan new ways of delivering care to large numbers of people while maintaining staff safety through greater physical separation. The rapid pivot to telemedicine and virtual care provided immediate and longer term benefits; however, such rapid-cycle development also created risks. OBJECTIVE: The aim of this study was to understand the sociotechnical aspects of the rapid-cycle development of seven different COVID-19 virtual care tools, and to identify enablers, barriers, and risks at three health services in Victoria, Australia. METHODS: A qualitative, embedded, multiple case study design was adopted. Researchers from three health services collaborated with university researchers who were independent from those health services to gather and analyze structured interview data from key people involved in either clinical or technical aspects of designing and deploying seven different virtual care tools. RESULTS: The overall objectives of each health service reflected the international requirements for managing large numbers of patients safely but remotely and for protecting staff. However, the governance, digital maturity, and specific use cases at each institution shaped the methodology and specific outcomes required. Dependence on key individuals and their domain knowledge within an existing governance framework generally enabled rapid deployment, but sometimes posed barriers. Existing relationships with technical service developers enabled strong solutions, which in some cases were highly scalable. Conventional project methodologies such as steering committees, scope, budget control, tight functional specification, consumer engagement and codesign, universal accessibility, and postimplementation evaluation were ignored almost universally in this environment. CONCLUSIONS: These three health services took a variety of approaches to the rapid-cycle development of virtual care tools to meet their urgent needs for triaging and remote monitoring during the first year of the COVID-19 pandemic. Their experiences provided insights into many social and technical barriers and enablers to the development of virtual care tools. If these are addressed proactively, they will improve clinical governance and technical management of future virtual care. Some changes can be made within individual health services, while others entail health system policy reforms. Enhancing the environment for virtual care tool design and implementation now will yield returns not only during future health emergencies but also in many more routine care settings.
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ItemAcquired bloodstream infection in the intensive care unit: incidence and attributable mortality(BMC, 2011)INTRODUCTION: To estimate the incidence of intensive care unit (ICU)-acquired bloodstream infection (BSI) and its independent effect on hospital mortality. METHODS: We retrospectively studied acquisition of BSI during admissions of >72 hours to adult ICUs from two university-affiliated hospitals. We obtained demographics, illness severity and co-morbidity data from ICU databases and microbiological diagnoses from departmental electronic records. We assessed survival at hospital discharge or at 90 days if still hospitalized. RESULTS: We identified 6339 ICU admissions, 330 of which were complicated by BSI (5.2%). Median time to first positive culture was 7 days (IQR 5-12). Overall mortality was 23.5%, 41.2% in patients with BSI and 22.5% in those without. Patients who developed BSI had higher illness severity at ICU admission (median APACHE III score: 79 vs. 68, P < 0.001). After controlling for illness severity and baseline demographics by Cox proportional-hazard model, BSI remained independently associated with risk of death (hazard ratio from diagnosis 2.89; 95% confidence interval 2.41-3.46; P < 0.001). However, only 5% of the deaths in this model could be attributed to acquired-BSI, equivalent to an absolute decrease in survival of 1% of the total population. When analyzed by microbiological classification, Candida, Staphylococcus aureus and gram-negative bacilli infections were independently associated with increased risk of death. In a sub-group analysis intravascular catheter associated BSI remained associated with significant risk of death (hazard ratio 2.64; 95% confidence interval 1.44-4.83; P = 0.002). CONCLUSIONS: ICU-acquired BSI is associated with greater in-hospital mortality, but complicates only 5% of ICU admissions and its absolute effect on population mortality is limited. These findings have implications for the design and interpretation of clinical trials.
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ItemArterial hyperoxia and in-hospital mortality after resuscitation from cardiac arrest(BIOMED CENTRAL LTD, 2011)INTRODUCTION: Hyperoxia has recently been reported as an independent risk factor for mortality in patients resuscitated from cardiac arrest. We examined the independent relationship between hyperoxia and outcomes in such patients. METHODS: We divided patients resuscitated from nontraumatic cardiac arrest from 125 intensive care units (ICUs) into three groups according to worst PaO2 level or alveolar-arterial O2 gradient in the first 24 hours after admission. We defined 'hyperoxia' as PaO2 of 300 mmHg or greater, 'hypoxia/poor O2 transfer' as either PaO2 < 60 mmHg or ratio of PaO2 to fraction of inspired oxygen (FiO2 ) < 300, 'normoxia' as any value between hypoxia and hyperoxia and 'isolated hypoxemia' as PaO2 < 60 mmHg regardless of FiO2. Mortality at hospital discharge was the main outcome measure. RESULTS: Of 12,108 total patients, 1,285 (10.6%) had hyperoxia, 8,904 (73.5%) had hypoxia/poor O2 transfer, 1,919 (15.9%) had normoxia and 1,168 (9.7%) had isolated hypoxemia (PaO2 < 60 mmHg). The hyperoxia group had higher mortality (754 (59%) of 1,285 patients; 95% confidence interval (95% CI), 56% to 61%) than the normoxia group (911 (47%) of 1,919 patients; 95% CI, 45% to 50%) with a proportional difference of 11% (95% CI, 8% to 15%), but not higher than the hypoxia group (5,303 (60%) of 8,904 patients; 95% CI, 59% to 61%). In a multivariable model controlling for some potential confounders, including illness severity, hyperoxia had an odds ratio for hospital death of 1.2 (95% CI, 1.1 to 1.6). However, once we applied Cox proportional hazards modelling of survival, sensitivity analyses using deciles of hypoxemia, time period matching and hyperoxia defined as PaO2 > 400 mmHg, hyperoxia had no independent association with mortality. Importantly, after adjustment for FiO2 and the relevant covariates, PaO2 was no longer predictive of hospital mortality (P = 0.21). CONCLUSIONS: Among patients admitted to the ICU after cardiac arrest, hyperoxia did not have a robust or consistently reproducible association with mortality. We urge caution in implementing policies of deliberate decreases in FiO2 in these patients.
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ItemAssessment of agreement and interchangeability between the TEG5000 and TEG6S thromboelastography haemostasis analysers: a prospective validation study(BMC, 2019-03-30)BACKGROUND: TEG6S® and TEG5000® (Haemonetics Corp, USA) are haemostasis analysers that measure viscoelasticity properties of whole blood. Both use different mechanisms to assess similar components of the coagulation process. The aim of this study was to assess agreement and interchangeability between the TEG6S and TEG5000 analysers. METHODS: 3.5 mL whole blood was collected from 25 adult patients in a tertiary intensive care unit (ICU). Analysis was performed using TEG6S and TEG5000 haemostatic platforms. Agreement between platforms was measured using Lin's concordance coefficient (Lin's CC), further validated using intraclass correlation coefficients and reduced major axis regression (RMAR). RESULTS: Sixteen (64%) patients were male; mean (range) age: 59yo (23-86). TEG6S and TEG5000 systems were broadly interchangeable. The majority of TEG variables demonstrated almost perfect or substantial agreement and minimal proportional bias (maximum amplitude demonstrated a fixed bias). LY30%, however, demonstrated poor agreement and a proportional bias. Lin's CC coefficients (95% CI, RMAR slope, intercept) between TEG6S and TEG5000 variables were: R time: 0.78 (0.64-0.92, 0.76, 0.92); K time: 0.82 (0.69-0.94, 1.30, - 0.93); alpha angle: 0.79 (0.64-0.95, 1.04, - 1.43); maximum amplitude (MA): 0.90 (0.83-0.96, 0.99, - 5.0); LY30%: 0.34 (0.1-0.58, 0.43, 0.04). CONCLUSIONS: Adult patients with critical illness demonstrate almost perfect agreement in the R time and MA, substantial agreement in K time and alpha angle, but poor agreement in LY30%, as measured by the TEG6S and TEG5000 analysers. With the exception of LY30%, the TEG6S and TEG5000 platforms appear interchangeable. This has important implications for use in clinical practice and multi-site research programs. TRIAL REGISTRATION: ANZCRT number: 12617000062325 , registered 12/Jan17. Retrospectively registered.
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ItemComparison of Thromboelastography and Conventional Coagulation Tests in Patients With Severe Liver Disease(SAGE PUBLICATIONS INC, 2020-06-03)OBJECTIVE: Thromboelastography (TEG) may provide rapid and clinically important coagulation information in acutely ill patients with chronic liver disease (CLD). Our objective was to describe the relationship between TEG and conventional coagulation tests (CCTs), which has not been previously explored in this population. METHODS: In acutely ill patients with severe CLD (Child-Pugh score > 9, category C), we conducted a prospective observational study investigating coagulation assessment as measured by both CCTs and TEG. We used quantile regression to explore 30 associations between TEG parameters and corresponding CCTs. We compared TEG and CCT measures of coagulation initiation, clot formation, clot strength, and fibrinolysis. RESULTS: We studied 34 patients on a total of 109 occasions. We observed inconsistent associations between TEG and CCT measures of coagulation initiation: TEG (citrated kaolin [CK] assay) standard reaction time and international normalized ratio: R 2 = 0.117 (P = .044). Conversely, there were strong and consistent associations between tests of clot formation: TEG (CK) kinetics time and fibrinogen: R 2 = 0.202 (P < .0001) and TEG (CK) α angle and fibrinogen 0.263 (P < .0001). We also observed strong associations between tests of clot strength, specifically TEG MA and conventional fibrinogen levels, across all TEG assays: MA (CK) and fibrinogen: R 2 = 0.485 (P < .0001). There were no associations between TEG and D-dimer levels. CONCLUSIONS: In acutely ill patients with CLD, there are strong and consistent associations between TEG measures of clot formation and clot strength and conventional fibrinogen levels. There are weak and/or inconsistent associations between TEG and all other conventional measures of coagulation.
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ItemLandmark survival as an end-point for trials in critically ill patients - comparison of alternative durations of follow-up: an exploratory analysis(BMC, 2009)INTRODUCTION: Interventional ICU trials have followed up patients for variable duration. However, the optimal duration of follow-up for the determination of mortality endpoint in such trials is uncertain. We aimed to determine the most logical and practical mortality end-point in clinical trials of critically ill patients. METHODS: We performed a retrospective analysis of prospectively collected data involving 369 patients with one of the three specific diagnoses (i) Sepsis (ii) Community acquired pneumonia (iii) Non operative trauma admitted to the Royal Perth Hospital ICU, a large teaching hospital in Western Australia (WA cohort). Their in-hospital and post discharge survival outcome was assessed by linkage to the WA Death Registry. A validation cohort involving 4609 patients admitted during same time period with identical diagnoses from 55 ICUs across Australia (CORE cohort) was used to compare the patient characteristics and in-hospital survival to look at the Australia-wide applicability of the long term survival data from the WA cohort. RESULTS: The long term outcome data of the WA cohort indicate that mortality reached a plateau at 90 days after ICU admission particularly for sepsis and pneumonia. Mortality after hospital discharge before 90 days was not uncommon in these two groups. Severity of acute illness as measured by the total number of organ failures or acute physiology score was the main predictor of 90-day mortality. The adjusted in-hospital survival for the WA cohort was not significantly different from that of the CORE cohort in all three diagnostic groups; sepsis (P = 0.19), community acquired pneumonia (P = 0.86), non-operative trauma (P = 0.47). CONCLUSIONS: A minimum of 90 days follow-up is necessary to fully capture the mortality effect of sepsis and community acquired pneumonia. A shorter period of follow-up time may be sufficient for non-operative trauma.
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ItemThe impact of early hypoglycemia and blood glucose variability on outcome in critical illness(BMC, 2009)INTRODUCTION: In critical illness, the association of hypoglycemia, blood glucose (BG) variability and outcome are not well understood. We describe the incidence, clinical factors and outcomes associated with an early hypoglycemia and BG variability in critically ill patients. METHODS: Retrospective interrogation of prospectively collected data from the Australia New Zealand Intensive Care Society Adult Patient Database on 66184 adult admissions to 24 intensive care units (ICUs) from 1 January 2000 to 31 December 2005. Primary exposure was hypoglycemia (BG < 4.5 mmol/L) and BG variability (BG < 4.5 and >or= 12.0 mmol/L) within 24 hours of admission. Primary outcome was all-cause mortality. RESULTS: The cumulative incidence of hypoglycemia and BG variability were 13.8% (95% confidence interval (CI) = 13.5 to 14.0; n = 9122) and 2.9% (95%CI = 2.8 to 3.0, n = 1913), respectively. Several clinical factors were associated with both hypoglycemia and BG variability including: co-morbid disease (P < 0.001), non-elective admissions (P < 0.001), higher illness severity (P < 0.001), and primary septic diagnosis (P < 0.001). Hypoglycemia was associated with greater odds of adjusted ICU (odds ratio (OR) = 1.41, 95% CI = 1.31 to 1.54) and hospital death (OR = 1.36, 95% CI = 1.27 to 1.46). Hypoglycemia severity was associated with 'dose-response' increases in mortality. BG variability was associated with greater odds of adjusted ICU (1.5, 95% CI = 1.4 to 1.6) and hospital (1.4, 95% CI = 1.3 to 1.5) mortality, when compared with either hypoglycemia only or neither. CONCLUSIONS: In critically ill patients, both early hypoglycemia and early variability in BG are relatively common, and independently portend an increased risk for mortality.
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ItemVery old patients admitted to intensive care in Australia and New Zealand: a multi-centre cohort analysis(BMC, 2009)INTRODUCTION: Older age is associated with higher prevalence of chronic illness and functional impairment, contributing to an increased rate of hospitalization and admission to intensive care. The primary objective was to evaluate the rate, characteristics and outcomes of very old (age >or= 80 years) patients admitted to intensive care units (ICUs). METHODS: Retrospective analysis of prospectively collected data from the Australian New Zealand Intensive Care Society Adult Patient Database. Data were obtained for 120,123 adult admissions for >or= 24 hours across 57 ICUs from 1 January 2000 to 31 December 2005. RESULTS: A total of 15,640 very old patients (13.0%) were admitted during the study. These patients were more likely to be from a chronic care facility, had greater co-morbid illness, greater illness severity, and were less likely to receive mechanical ventilation. Crude ICU and hospital mortalities were higher (ICU: 12% vs. 8.2%, P < 0.001; hospital: 24.0% vs. 13%, P < 0.001). By multivariable analysis, age >/= 80 years was associated with higher ICU and hospital death compared with younger age strata (ICU: odds ratio (OR) = 2.7, 95% confidence interval (CI) = 2.4 to 3.0; hospital: OR = 5.4, 95% CI = 4.9 to 5.9). Factors associated with lower survival included admission from a chronic care facility, co-morbid illness, nonsurgical admission, greater illness severity, mechanical ventilation, and longer stay in the ICU. Those aged >or= 80 years were more likely to be discharged to rehabilitation/long-term care (12.3% vs. 4.9%, OR = 2.7, 95% CI = 2.6 to 2.9). The admission rates of very old patients increased by 5.6% per year. This potentially translates to a 72.4% increase in demand for ICU bed-days by 2015. CONCLUSIONS: The proportion of patients aged >or= 80 years admitted to intensive care in Australia and New Zealand is rapidly increasing. Although these patients have more co-morbid illness, are less likely to be discharged home, and have a greater mortality than younger patients, approximately 80% survive to hospital discharge. These data also imply a potential major increase in demand for ICU bed-days for very old patients within a decade.
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ItemIntroduction of Medical Emergency Teams in Australia and New Zealand: a multi-centre study(BMC, 2008)INTRODUCTION: Information about Medical Emergency Teams (METs) in Australia and New Zealand (ANZ) is limited to local studies and a cluster randomised controlled trial (the Medical Emergency Response and Intervention Trial [MERIT]). Thus, we sought to describe the timing of the introduction of METs into ANZ hospitals relative to relevant publications and to assess changes in the incidence and rate of intensive care unit (ICU) admissions due to a ward cardiac arrest (CA) and ICU readmissions. METHODS: We used the Australian and New Zealand Intensive Care Society database to obtain the study data. We related MET introduction to publications about adverse events and MET services. We compared the incidence and rate of readmissions and admitted CAs from wards before and after the introduction of an MET. Finally, we identified hospitals without an MET system which had contributed to the database for at least two years from 2002 to 2005 and measured the incidence of adverse events from the first year of contribution to the second. RESULTS: The MET status was known for 131 of the 172 (76.2%) hospitals that did not participate in the MERIT study. Among these hospitals, 110 (64.1%) had introduced an MET service by 2005. In the 79 hospitals in which the MET commencement date was known, 75% had introduced an MET by May 2002. Of the 110 hospitals in which an MET service was introduced, 24 (21.8%) contributed continuous data in the year before and after the known commencement date. In these hospitals, the mean incidence of CAs admitted to the ICU from the wards changed from 6.33 per year before to 5.04 per year in the year after the MET service began (difference of 1.29 per year, 95% confidence interval [CI] -0.09 to 2.67; P = 0.0244). The incidence of ICU readmissions and the mortality for both ICU-admitted CAs from wards and ICU readmissions did not change. Data were available to calculate the change in ICU admissions due to ward CAs for 16 of 62 (25.8%) hospitals without an MET system. In these hospitals, admissions to the ICU after a ward CA decreased from 5.0 per year in the first year of data contribution to 4.2 per year in the following year (difference of 0.8 per year, 95% CI -0.81 to 3.49; P = 0.3). CONCLUSION: Approximately 60% of hospitals in ANZ with an ICU report having an MET service. Most introduced the MET service early and in association with literature related to adverse events. Although available in only a quarter of hospitals, temporal trends suggest an overall decrease in the incidence of ward CAs admitted to the ICU in MET as well as non-MET hospitals.
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ItemLong term effect of a medical emergency team on cardiac arrests in a teaching hospital(BMC, 2005-12)INTRODUCTION: It is unknown whether the reported short-term reduction in cardiac arrests associated with the introduction of the medical emergency team (MET) system can be sustained. METHOD: We conducted a prospective, controlled before-and-after examination of the effect of a MET system on the long-term incidence of cardiac arrests. We included consecutive patients admitted during three study periods: before the introduction of the MET; during the education phase preceding the implementation of the MET; and a period of four years from the implementation of the MET system. Cardiac arrests were identified from a log book of cardiac arrest calls and cross-referenced with case report forms and the intensive care unit admissions database. We measured the number of hospital admissions and MET reviews during each period, performed multivariate logistic regression analysis to identify predictors of mortality following cardiac arrest and studied the correlation between the rate of MET calls with the rate of cardiac arrests. RESULTS: Before the introduction of the MET system there were 66 cardiac arrests and 16,246 admissions (4.06 cardiac arrests per 1,000 admissions). During the education period, the incidence of cardiac arrests decreased to 2.45 per 1,000 admissions (odds ratio (OR) for cardiac arrest 0.60; 95% confidence interval (CI) 0.43-0.86; p = 0.004). After the implementation of the MET system, the incidence of cardiac arrests further decreased to 1.90 per 1,000 admissions (OR for cardiac arrest 0.47; 95% CI 0.35-0.62; p < 0.0001). There was an inverse correlation between the number of MET calls in each calendar year and the number of cardiac arrests for the same year (r2 = 0.84; p = 0.01), with 17 MET calls being associated with one less cardiac arrest. Male gender (OR 2.88; 95% CI 1.34-6.19) and an initial rhythm of either asystole (OR 7.58; 95% CI 3.15-18.25; p < 0.0001) or pulseless electrical activity (OR 4.09; 95% CI 1.59-10.51; p = 0.003) predicted an increased risk of death. CONCLUSION: Introduction of a MET system into a teaching hospital was associated with a sustained and progressive reduction in cardiac arrests over a four year period. Our findings show sustainability and suggest that, for every 17 MET calls, one cardiac arrest might be prevented.