Critical Care - Research Publications

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    Is reducing variability of blood glucose the real but hidden target of intensive insulin therapy?
    Egi, M ; Bellomo, R ; Reade, MC (BMC, 2009)
    Since the first report that intensive insulin therapy reduced mortality in selected surgical critically ill patients, lowering of blood glucose levels has been recommended as a means of improving patient outcomes. In this initial Leuven trial, blood glucose control by protocol using insulin was applied to 98.7% of patients in the intensive group but to only 39.2% (P < 0.0001) of patients in the control group. If appropriately applied, such protocols should decrease both the mean blood glucose concentration and its variability (variation of blood glucose concentration). Thus, it is logically possible that the benefit of intensive insulin therapy in the first Leuven trial was due to a decrease in mean glucose levels, a decrease in their variability, or both. Several recent studies have confirmed significant associations between variability of blood glucose levels and patient outcomes. Decreasing the variability of blood glucose levels might be an important dimension of glucose management, a possible mechanism by which an intensive insulin protocol exerts its putative beneficial effects, and an important goal of glucose management in the intensive care unit. Clinicians need to be aware of this controversy when considering the application of intensive insulin therapy and interpreting future trials.
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    Effectiveness of the Medical Emergency Team: the importance of dose
    Jones, D ; Bellomo, R ; DeVita, MA (BMC, 2009)
    Up to 17% of hospital admissions are complicated by serious adverse events unrelated to the patients presenting medical condition. Rapid Response Teams (RRTs) review patients during early phase of deterioration to reduce patient morbidity and mortality. However, reports of the efficacy of these teams are varied. The aims of this article were to explore the concept of RRT dose, to assess whether RRT dose improves patient outcomes, and to assess whether there is evidence that inclusion of a physician in the team impacts on the effectiveness of the team. A review of available literature suggested that the method of reporting RRT utilization rate, (RRT dose) is calls per 1,000 admissions. Hospitals with mature RRTs that report improved patient outcome following RRT introduction have a RRT dose between 25.8 and 56.4 calls per 1,000 admissions. Four studies report an association between increasing RRT dose and reduced in-hospital cardiac arrest rates. Another reported that increasing RRT dose reduced in-hospital mortality for surgical but not medical patients. The MERIT study investigators reported a negative relationship between MET-like activity and the incidence of serious adverse events. Fourteen studies reported improved patient outcome in association with the introduction of a RRT, and 13/14 involved a Physician-led MET. These findings suggest that if the RRT is the major method for reviewing serious adverse events, the dose of RRT activation must be sufficient for the frequency and severity of the problem it is intended to treat. If the RRT dose is too low then it is unlikely to improve patient outcomes. Increasing RRT dose appears to be associated with reduction in cardiac arrests. The majority of studies reporting improved patient outcome in association with the introduction of an RRT involve a MET, suggesting that inclusion of a physician in the team is an important determinant of its effectiveness.
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    Guidance in sepsis management: navigating uncharted waters?
    Reade, MC ; Warrillow, SJ ; Myburgh, JA ; Bellomo, R (BMC, 2008)
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    The pursuit of a high central venous oxygen saturation in sepsis: growing concerns
    Bellomo, R ; Reade, MC ; Warrillow, SJ (BMC, 2008)
    In this issue of Critical Care, Dutch investigators report that, in a cohort of patients with sepsis/septic shock admitted to three different intensive care units (ICUs), low central venous oxygen saturation (ScvO2) was uncommon at the time of ICU admission, and hospital mortality was <30%. Their findings, taken together with those of recent reports from Australia and New Zealand (ANZ), raise serious concerns about the utility of early goal directed therapy (EGDT) outside the context of the original trial. Despite inclusion of EGDT into the Surviving Sepsis Guidelines, in response to growing uncertainty, ANZ and US investigators will soon begin randomization of patients into two large multicentre trials comparing EGDT to standard therapy. Until such studies are completed, basing international treatment guidelines on a single centre study performed in what may turn out to be a highly atypical environment would seem premature.
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    Bench-to-bedside review: The evaluation of complex interventions in critical care
    Delaney, A ; Angus, DC ; Bellomo, R ; Cameron, P ; Cooper, DJ ; Finfer, S ; Harrison, DA ; Huang, DT ; Myburgh, JA ; Peake, SL ; Reade, MC ; Webb, SAR ; Yealy, DM (BIOMED CENTRAL LTD, 2008)
    Complex interventions, such as the introduction of medical emergency teams or an early goal-directed therapy protocol, are developed from a number of components that may act both independently and inter-dependently. There is an emerging body of literature advocating the use of integrated complex interventions to optimise the treatment of critically ill patients. As with any other treatment, complex interventions should undergo careful evaluation prior to widespread introduction into clinical practice. During the development of an international collaboration of researchers investigating protocol-based approaches to the resuscitation of patients with severe sepsis, we examined the specific issues related to the evaluation of complex interventions. This review outlines some of these issues. The issues specific to trials of complex interventions that require particular attention include determining an appropriate study population and defining current treatments and outcomes in that population, defining the study intervention and the treatment to be used in the control group, and deploying the intervention in a standardised manner. The context in which the research takes place, including existing staffing levels and existing protocols and procedures, is crucial. We also discuss specific details of trial execution, in particular randomization, blinded outcome adjudication and analysis of the results, which are key to avoiding bias in the design and interpretation of such trials. These aspects of study design impact upon the evaluation of complex interventions in critical care. Clinicians should also consider these specific issues when implementing new complex interventions into their practice.
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    Bench-to-bedside review: The MET syndrome - the challenges of researching and adopting medical emergency teams
    Tee, A ; Calzavacca, P ; Licari, E ; Goldsmith, D ; Bellomo, R (BMC, 2008)
    Studies of hospital performance highlight the problem of 'failure to rescue' in acutely ill patients. This is a deficiency strongly associated with serious adverse events, cardiac arrest, or death. Rapid response systems (RRSs) and their efferent arm, the medical emergency team (MET), provide early specialist critical care to patients affected by the 'MET syndrome': unequivocal physiological instability or significant hospital staff concern for patients in a non-critical care environment. This intervention aims to prevent serious adverse events, cardiac arrests, and unexpected deaths. Though clinically logical and relatively simple, its adoption poses major challenges. Furthermore, research about the effectiveness of RRS is difficult to conduct. Skeptics argue that inadequate evidence exists to support its widespread application. Indeed, supportive evidence is based on before-and-after studies, observational investigations, and inductive reasoning. However, implementing a complex intervention like RRS poses enormous logistic, political, cultural, and financial challenges. In addition, double-blinded randomised controlled trials of RRS are simply not possible. Instead, as in the case of cardiac arrest and trauma teams, change in practice may be slow and progressive, even in the absence of level I evidence. It appears likely that the accumulation of evidence from different settings and situations, though methodologically imperfect, will increase the rationale and logic of RRS. A conclusive randomised controlled trial is unlikely to occur.
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    Ethics roundtable debate: Patients and surrogates want 'everything done' - what does 'everything' mean?
    Doig, C ; Murray, H ; Bellomo, R ; Kuiper, M ; Costa, R ; Azoulay, E ; Crippen, D (BIOMED CENTRAL LTD, 2006)
    Highly complex and specialized care plans sometimes overwhelm the comprehension of patients and families. Many optimistic surrogates of critically ill patients err on the side of desiring that everything be done but with a nebulous idea of what 'everything' entails. Physicians must work closely to educate surrogates as to the benefits versus the risks of treatment. Our roundtable experts ponder the question of whether providers possess the authority to interpret unilaterally the nature of requests for everything.
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    Introduction of a rapid response system: why we are glad we MET
    Jones, D ; Bellomo, R (BIOMED CENTRAL LTD, 2006)
    Hospital patients can experience serious adverse events during their stay. To identify, review and treat these patients and to prevent serious adverse events, we introduced a medical emergency team (MET) service into our hospital in September 2000 following a 1-year period of preparation and education. The introduction of the MET into our institution has been associated with profound changes to cultural and medical practice that have affected the way in which the intensive care unit and the hospital view the roles of junior doctors, nurses, intensive care physicians, and senior doctors. These changes have also been associated with a progressive reduction in the incidence of cardiac arrests of close to 70%. Furthermore, they have allowed improved analysis and characterization of 'at-risk' patients and their needs. Four years later, we remain glad we MET.
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    Evidence-based medicine: Classifying the evidence from clinical trials - the need to consider other dimensions
    Bellomo, R ; Bagshaw, SM (BMC, 2006)
    The current approach to assessing the quality of evidence obtained from clinical trials focuses on three dimensions: the quality of the design (with double-blinded randomised controlled trials representing the highest level of such design); the statistical power (beta) and the level of significance (alpha). While these aspects are important, we argue that other significant aspects of trial quality impinge upon the truthfulness of the findings: biological plausibility, reproducibility and generalisability. We present several recent studies in critical care medicine where the design, beta and alpha components of the study are seemingly satisfactory but where the aspects of biological plausibility, reproducibility and generalisability show serious limitations. Accordingly, we argue for more reflection, definition and consensus on these aspects of the evaluation of evidence.
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    Bench-to-bedside review: Inotropic drug therapy after adult cardiac surgery - a systematic literature review
    Gillies, M ; Bellomo, R ; Doolan, L ; Buxton, B (BMC, 2005-06)
    Many adult patients require temporary inotropic support after cardiac surgery. We reviewed the literature systematically to establish, present and classify the evidence regarding choice of inotropic drugs. The available evidence, while limited in quality and scope, supports the following observations; although all beta-agonists can increase cardiac output, the best studied beta-agonist and the one with the most favourable side-effect profile appears to be dobutamine. Dobutamine and phosphodiesterase inhibitors (PDIs) are efficacious inotropic drugs for management of the low cardiac output syndrome. Dobutamine is associated with a greater incidence of tachycardia and tachyarrhythmias, whereas PDIs often require the administration of vasoconstrictors. Other catecholamines have no clear advantages over dobutamine. PDIs increase the likelihood of successful weaning from cardiopulmonary bypass as compared with placebo. There is insufficient evidence that inotropic drugs should be selected for their effects on regional perfusion. PDIs also increase flow through arterial grafts, reduce mean pulmonary artery pressure and improve right heart performance in pulmonary hypertension. Insufficient data exist to allow selection of a specific inotropic agent in preference over another in adult cardiac surgery patients. Multicentre randomized controlled trials focusing on clinical rather than physiological outcomes are needed.