Peter Stow

Diabetic status and the relation of the three domains of glycemic control to mortality in critically ill patients: an international multicenter cohort study.

IntroductionHyperglycemia, hypoglycemia, and increased glycemic variability have each beenindependently associated with increased risk of mortality in critically illpatients. The role of diabetic status on modulating the relation of these threedomains of glycemic control with mortality remains uncertain. The purpose of thisinvestigation was to determine how diabetic status affects the relation ofhyperglycemia, hypoglycemia, and increased glycemic variability with the risk ofmortality in critically ill patients.MethodsThis is a retrospective analysis of prospectively collected data involving 44,964patients admitted to 23 intensive care units (ICUs) from nine countries, betweenFebruary 2001 and May 2012. We analyzed mean blood glucose concentration (BG),coefficient of variation (CV), and minimal BG and created multivariable models toanalyze their independent association with mortality. Patients were stratifiedaccording to the diagnosis of diabetes.ResultsAmong patients without diabetes, mean BG bands between 80 and 140 mg/dl wereindependently associated with decreased risk of mortality, and mean BG bands> 140 mg/dl, with increased risk of mortality. Among patients withdiabetes, mean BG from 80 to 110 mg/dl was associated with increased risk ofmortality and mean BG from 110 to 180 mg/dl with decreased risk of mortality. Aneffect of center was noted on the relation between mean BG and mortality.Hypoglycemia, defined as minimum BG <70 mg/dl, was independently associatedwith increased risk of mortality among patients with and without diabetes andincreased glycemic variability, defined as CV > 20%, was independentlyassociated with increased risk of mortality only among patients without diabetes.Derangements of more than one domain of glycemic control had a cumulativeassociation with mortality, especially for patients without diabetes.ConclusionsAlthough hyperglycemia, hypoglycemia, and increased glycemic variability is eachindependently associated with mortality in critically ill patients, diabeticstatus modulates these relations in clinically important ways. Our findingssuggest that patients with diabetes may benefit from higher glucose target rangesthan will those without diabetes. Additionally, hypoglycemia is independentlyassociated with increased risk of mortality regardless of the patients diabeticstatus, and increased glycemic variability is independently associated withincreased risk of mortality among patients without diabetes.See related commentary by Krinsley,http://ccforum.com/content/17/2/131See related commentary by Finfer and Billot,http://ccforum.com/content/17/2/134

Arterial carbon dioxide tension and outcome in patients admitted to the intensive care unit after cardiac arrest

BACKGROUND Arterial carbon dioxide tension (PaCO2) affects neuronal function and cerebral blood flow. However, its association with outcome in patients admitted to intensive care unit (ICU) after cardiac arrest (CA) has not been evaluated. METHODS AND RESULTS Observational cohort study using data from the Australian New Zealand (ANZ) Intensive Care Society Adult-Patient-Database (ANZICS-APD). Outcomes analyses were adjusted for illness severity, co-morbidities, hypothermia, treatment limitations, age, year of admission, glucose, source of admission, PaO2 and propensity score. We studied 16,542 consecutive patients admitted to 125 ANZ ICUs after CA between 2000 and 2011. Using the APD-PaCO2 (obtained within 24 h of ICU admission), 3010 (18.2%) were classified into the hypo- (PaCO2<35 mmHg), 6705 (40.5%) into the normo- (35-45 mmHg) and 6827 (41.3%) into the hypercapnia (>45 mmHg) group. The hypocapnia group, compared with the normocapnia group, had a trend toward higher in-hospital mortality (OR 1.12 [95% CI 1.00-1.24, p=0.04]), lower rate of discharge home (OR 0.81 [0.70-0.94, p<0.01]) and higher likelihood of fulfilling composite adverse outcome of death and no discharge home (OR 1.23 [1.10-1.37, p<0.001]). In contrast, the hypercapnia group had similar in-hospital mortality (OR 1.06 [0.97-1.15, p=0.19]) but higher rate of discharge home among survivors (OR 1.16 [1.03-1.32, p=0.01]) and similar likelihood of fulfilling the composite outcome (OR 0.97 [0.89-1.06, p=0.52]). Cox-proportional hazards modelling supported these findings. CONCLUSIONS Hypo- and hypercapnia are common after ICU admission post-CA. Compared with normocapnia, hypocapnia was independently associated with worse clinical outcomes and hypercapnia a greater likelihood of discharge home among survivors.

Circadian rhythm of blood glucose values in critically ill patients

Objective:To test whether there is a circadian rhythm of blood glucose control in critically ill patients and whether morning blood glucose is an accurate surrogate of overall blood glucose control. Design:Retrospective multiple-center observational study. Setting:Intensive care units of three tertiary hospitals and one affiliated private hospital. Patients:Cohort of 8,307 consecutive critically ill patients. Interventions:Extraction of blood glucose values from electronically stored measurements. Extraction of demographic and outcome data from unit and hospital databases. Statistical assessment of variations in blood glucose control over each 24-hr cycle. Measurements and Main Results:We studied 208,362 blood glucose measurements in 8,307 patients (5.5 measurements/day/person). In each hospital, there was a circadian rhythm of blood glucose control (p < .0001). The differences between highest and lowest blood glucose concentration in different time periods in each hospital were 0.27, 0.28, 0.95, and 0.22 mmol/L. There was also significant variation in the incidence and notional duration of hyperglycemia. The differences between the lowest and highest incidence of hyperglycemia in different time periods were 3.3, 2.7, 9.9, and 2.6% in each hospital. In all four hospitals, the average blood glucose value from 5:30 am to 6:30 am was significantly lower than the 24-hr average. Conclusions:Blood glucose values and the incidence of hyperglycemia have a circadian rhythm in critically ill patients. Morning blood glucose may not be an accurate surrogate of blood glucose control over the daily cycle.

Why is there such a difference in outcome between Australian intensive care units and others

Purpose of review The aim of this article is to assess the data on clinical outcomes for critically ill patients admitted to Australian and New Zealand intensive care units in comparison to information available for similar patients in other counties Recent findings Australia and New Zealand have been collecting standardized data intensive care unit admissions for over a decade. The Australian and New Zealand Intensive Care Society Database Management Committee has developed a high quality database of close to 600 000 adult intensive care unit admissions. Although comparisons suffer from significant methodological, case-mix and process differences, which make their findings easily subject to criticism, interrogation of this database and of data from clusters of intensive care units within this system consistently yields patient outcomes, which are better than outcomes reported from other nations or international studies for similar patients. In addition, Australia and New Zealand has now achieved the highest rate of patient enrolment in an investigator-initiated multicentre randomized controlled trials. Summary Although comparisons in outcome between Australia and New Zealand intensive care units and other units worldwide may not have sufficient scientific rigour to truly reflect better national outcomes, many features of Australian and New Zealand units are unique and worthy of consideration by other national systems as they consider their strategic national goals for the next decade.

Improved outcomes from acute severe asthma in Australian intensive care units (1996 – 2003)

Background: There is limited information on changes in the epidemiology and outcome of patients with asthma admitted to intensive care units (ICUs) in the last decade. A database sampling intensive care activity in hospitals throughout Australia offers the opportunity to examine these changes. Methods: The Australian and New Zealand Intensive Care Society Adult Patient Database was examined for all patients with asthma admitted to ICUs from 1996 to 2003. Demographic, physiological and outcome information was obtained and analysed from 22 hospitals which had submitted data continuously over this period. Results: ICU admissions with the primary diagnosis of asthma represented 1899 (1.5%) of 126 906 admissions during the 8-year period. 36.1% received mechanical ventilation during the first 24 h. The overall incidence of admission to ICU fell from 1.9% in 1996 to 1.1% in 2003 (p<0.001). Overall hospital mortality was 3.2%. There was a significant decline in mortality from a peak of 4.7% in 1997 to 1.1% in 2003 (p = 0.014). This was despite increasing severity of illness (as evidenced by an increasing predicted risk of death derived from the APACHE II score) over the 8-year period (p = 0.002). Conclusions: There has been a significant decline in the incidence of asthma requiring ICU admission between 1996 and 2003 among units sampled by the Australian and New Zealand Intensive Care Society Adult Patient Database. The mortality of these patients has also decreased over time and is lower than reported in other studies.

Monitoring the rate of re-exploration for excessive bleeding after cardiac surgery in adults

Background: The monitoring of adverse events in clinical care can be an important part of quality assurance. There is little evidence on the monitoring of re-exploration after cardiac surgery. Objective: To apply statistical monitoring techniques to the rate of re-exploration for excessive bleeding in adult patients undergoing cardiac surgery procedures using cardiopulmonary bypass at Geelong Hospital, Victoria, Australia, between 1997 and 2003. Methods: Shewhart charts, moving average plots and cumulative sum (CUSUM) charts were used to demonstrate changes in the rate of re-exploration over time. Results: A CUSUM chart was used retrospectively at a time of perceived deteriorating clinical outcomes in patients of the cardiac surgery service. At this time, an intervention aimed at reducing the re-exploration rate was performed, and subsequent CUSUM charts indicated an improvement in this rate. The CUSUM chart has become an important part of the quality feedback of clinical care outcomes within the Anaesthesia & Pain Management unit of Geelong Hospital. Conclusion: Statistical monitoring techniques for quality assurance can identify important changes in clinical performance, and their adoption by clinicians is recommended.

Skeletal morbidity among survivors of critical illness.

Objectives: To describe the incident fracture rate in survivors of critical illness and to compare fracture risk with population-matched control subjects. Design: Retrospective longitudinal case–cohort study. Setting: A tertiary adult intensive care unit in Australia. Patients: All patients ventilated admitted to intensive care and requiring mechanical ventilation for ≥48 hrs between January 1998 and December 2005. Interventions: None. Measurements and Main Results: New fractures were identified in the study population for the postintensive care unit period (intensive care unit discharge to January 2008). The incident fracture rate and age-adjusted fracture risk of the female intensive care unit population were compared with the general population adult females derived from the Geelong Osteoporosis Study. Over the 8-yr period, a total of 739 patients (258 women, 481 men) were identified. After a median follow-up of 3.7 yrs (interquartile range, 2.0–5.9 yrs) for women and 4.0 yrs (interquartile range, 2.1–6.1 yrs) for men, incident fracture rates (95% confidence interval) per 100 patient years were 3.84 (2.58–5.09) for females 2.41 (1.73–3.09) for males. Compared with an age-matched random population-based sample of women, elderly women were at increased risk for sustaining an osteoporosis-related fracture after critical illness (hazard ratio, 1.65; 95% confidence interval, 1.08–2.52; p = .02). Conclusions: The increase in fracture risk observed in postintensive care unit older females suggests an association between critical illness and subsequent skeletal morbidity. The explanation for this association is not explored in this study and includes the effects of pre-existing patient factors and/or direct effects of critical illness. Prospective research evaluating risk factors, the relationship between critical illness and bone turnover, the extent and duration of bone loss, and the associated morbidity in this population is warranted.

Designing and implementing an Australian and New Zealand intensive care data audit study

PURPOSE The aim of this pilot audit study is to develop and test a model to examine existing adult patient database (APD) data quality. DESIGN/METHODOLOGY/APPROACH A database was created to audit 50 records per site to determine accuracy. The audited records were randomly selected from the calendar year 2004 and four sites participated in the pilot audit study. A total of 41 data elements were assessed for data quality--those elements required for APACHE II scoring system. FINDINGS Results showed that the audit was feasible; missing audit data were an unplanned problem; analysis was complicated owing to the way the APACHE calculations are performed and 50 records per site was too time-consuming. ORIGINALITY/VALUE This is the first audit study of intensive care data within the ANZICS APD and demonstrates how to determine data quality in a large database containing individual patient records.