IntroductionDuring critical illness, oliguria is often used as a biomarker of acute kidney injury (AKI). However, its relationship with the subsequent development of AKI has not been prospectively evaluated.MethodsWe documented urine output and daily serum creatinine concentration in patients admitted for more than 24 hours in seven intensive care units (ICUs) from six countries over a period of two to four weeks. Oliguria was defined by a urine output < 0.5 ml/kg/hr. Data were collected until the occurrence of creatinine-defined AKI (AKI-Cr), designated by RIFLE-Injury class or greater using creatinine criteria (RIFLE-I[Cr]), or until ICU discharge. Episodes of oliguria were classified by longest duration of consecutive oliguria during each day were correlated with new AKI-Cr the next day, examining cut-offs for oliguria of greater than 1,2,3,4,5,6, or 12 hr duration,ResultsWe studied 239 patients during 723 days. Overall, 32 patients had AKI on ICU admission, while in 23, AKI-Cr developed in ICU. Oliguria of greater than one hour was significantly associated with AKI-Cr the next day. On receiver-operator characteristic area under the curve (ROCAUC) analysis, oliguria showed fair predictive ability for AKI-Cr (ROCAUC = 0.75; CI:0.64-0.85). The presence of 4 hrs or more oliguria provided the best discrimination (sensitivity 52% (0.31-0.73%), specificity 86% (0.84-0.89%), positive likelihood ratio 3.8 (2.2-5.6), P < 0.0001) with negative predictive value of 98% (0.97-0.99). Oliguria preceding AKI-Cr was more likely to be associated with lower blood pressure, higher heart rate and use of vasopressors or inotropes and was more likely to prompt clinical intervention. However, only 30 of 487 individual episodes of oliguria preceded the new occurrence of AKI-Cr the next day.ConclusionsOliguria was significantly associated with the occurrence of new AKI-Cr, however oliguria occurred frequently compared to the small number of patients (~10%) developing AKI-Cr in the ICU, so that most episodes of oliguria were not followed by renal injury. Consequently, the occurrence of short periods (1-6 hr) of oliguria lacked utility in discriminating patients with incipient AKI-Cr (positive likelihood ratios of 2-4, with > 10 considered indicative of a useful screening test). However, oliguria accompanied by hemodynamic compromise or increasing vasopressor dose may represent a clinically useful trigger for other early biomarkers of renal injury.

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Short-term perioperative atorvastatin use was not associated with a reduced incidence of postoperative AKI or smaller increases in urinary NGAL. (ClinicalTrials.gov NCT00910221).

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Delayed Medical Emergency Team activation and NFR orders are the strongest independent predictors of mortality in patients receiving a Medical Emergency Team review. Avoidance of delayed Medical Emergency Team activation should be a priority for hospitals operating rapid response systems.

Novel acute kidney injury (AKI) biomarkers offer promise of earlier diagnosis and risk stratification, but have yet to find widespread clinical application. We measured urinary a and glutathione S-transferases (a-GST and -GST), urinary L-type fatty acid-binding protein (L-FABP), urinary neutrophil gelatinase-associated lipocalin (NGAL), urinary hepcidin and serum cystatin c (CysC) before surgery, post-operatively and at 24 h after surgery in 93 high risk patient undergoing cardiopulmonary bypass (CPB) and assessed the ability of these biomarkers alone and in combination to predict RIFLE-R defined AKI in the first 5 post-operative days. Twenty-five patients developed AKI. Despite statistical significance in receiver-operator characteristic (ROC) analysis, when assessed by ability to define patients to two groups at high and low risk of AKI, combinations failed to significantly improve classification of risk compared to the best single biomarkers. In an alternative approach using Classification and Regression Tree (CART) analysis a model involving NGAL:Cr measurement post-op followed by Hepcidin:Cr at 24 h was developed which identified high, intermediate and low risk groups for AKI. Regression tree analysis has the potential produce models with greater clinical utility than single combined scores.

SummaryWe proposed that many Intensive Care Unit (ICU) patients would be hypothermic in the early postoperative period and that hypothermia would be associated with increased mortality. We retrospectively reviewed patients admitted to ICU after surgery. We recorded the lowest temperature in the first 24 h after surgery using tympanic membrane thermometers. We defined hypothermia as < 36°C, and severe hypothermia as < 35°C. We studied 5050 consecutive patients: 35% were hypothermic and 6% were severely hypothermic. In-hospital mortality was 5.6% for normothermic patients, 8.9% for all hypothermic patients (p < 0.001), and 14.7% for severely hypothermic patients (p < 0.001). Hypothermia was associated with in-hospital mortality: OR 1.83 for each degree Celsius (°C) decrease (95% CI: 1.2-2.60, p < 0.001). Given the evidence for improved outcome associated with active patient warming during surgery we suggest conducting prospective studies of active warming of patients admitted to ICU after surgery.

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. Sceptics 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, doubleblinded 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. All truth passes through three stages.First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.Arthur Schopenhauer (1788-1860), German philosopher IntroductionHospitals now treat increasingly complex patients. Despite the growth of technology and the development of new medications, 10% to 20% of hospitalised patients develop adverse events, with an overall hospital mortality of 5% to 8% [1][2][3]. Importantly, an estimated 37% of these events may be preventable [3]. Multiple studies from Europe, the US, and Australia have also confirmed deficiencies in the way hospitals and 'traditional' models of care respond to acute illness in the wards [4][5][6][7]. One deficiency of the hospital system's approach to acute illness is the problem of 'failure to rescue ' [8]: failure to deliver rapid and competent care to an acutely ill ward patient. Traditionally, hospitals have left such rapid responses to either the parent unit or cardiac arrest teams. Unfortunately, the parent unit doctors are often unable to attend the patient rapidly or are not specifically or sufficiently trained in acute resuscitation [4][5][6][7]. Although cardiac arrest teams have been around for decades, they often arrive at the end of the disease cascade, are unsuccessful in greater than 85% of patients, and patients so treated may survive the arrest but carry a high risk of hypoxic brain injury [9][10][11]. These observations suggest that earlier recognition of dis...