Intensive Insulin Therapy in Intensive Care: An Example of the Struggle to Implement Evidence-Based Medicine

Schultz and colleagues discuss the factors hindering implementation of intensive insulin therapy

Laboratory prediction of the requirement for renal replacement in acute falciparum malaria

BACKGROUND: Acute renal failure is a common complication of severe malaria in adults, and without renal replacement therapy (RRT), it carries a poor prognosis. Even when RRT is available, delaying its initiation may increase mortality. Earlier identification of patients who will need RRT may improve outcomes. METHOD: Prospectively collected data from two intervention studies in adults with severe malaria were analysed focusing on laboratory features on presentation and their association with a later requirement for RRT. In particular, laboratory indices of acute tubular necrosis (ATN) and acute kidney injury (AKI) that are used in other settings were examined. RESULTS: Data from 163 patients were available for analysis. Whether or not the patients should have received RRT (a retrospective assessment determined by three independent reviewers) was used as the reference. Forty-three (26.4%) patients met criteria for dialysis, but only 19 (44.2%) were able to receive this intervention due to the limited availability of RRT. Patients with impaired renal function on admission (creatinine clearance < 60 ml/min) (n = 84) had their laboratory indices of ATN/AKI analysed. The plasma creatinine level had the greatest area under the ROC curve (AUC): 0.83 (95% confidence interval 0.74-0.92), significantly better than the AUCs for, urinary sodium level, the urea to creatinine ratio (UCR), the fractional excretion of urea (FeUN) and the urinary neutrophil gelatinase-associated lipocalcin (NGAL) level. The AUC for plasma creatinine was also greater than the AUC for blood urea nitrogen level, the fractional excretion of sodium (FeNa), the renal failure index (RFI), the urinary osmolality, the urine to plasma creatinine ratio (UPCR) and the creatinine clearance, although the difference for these variables did not reach statistical significance. CONCLUSIONS: In adult patients with severe malaria and impaired renal function on admission, none of the evaluated laboratory indices was superior to the plasma creatinine level when used to predict a later requirement for renal replacement therapy

Biological markers for kidney injury and renal function in the intensive care unit

The purpose of the investigations described in this thesis was to seek for answers to two relevant questions in ICUs in resource-rich settings, i.e., can new biological markers play a role in early recognition of AKI, and can new biological markers predict recovery of renal function in patients who receive CVVH? A second aim was to answer a relevant question in ICUs in resource-poor settings, i.e., can novel biological markers predict development of AKI and need for RRT in patients with severe P. falciparum malaria? Both CyC and NGAL have been suggested promising endogenous biological markers for AKI in ICU patients. Results from the prospective observational SCARF study suggests that neither CyC nor NGAL are useful biological markers for AKI and need for RRT. The patient population in SCARF is rather heterogeneous. We believe this cohort better reflects the patient populations seen in the ICU in whom the abovementioned questions are relevant. Based on the findings in the SCARF study and its secondary analyses we conclude CyC and NGAL cannot serve as biological markers in clinical practice. As suPAR has a good prognostic value in patients with the systemic inflammatory response syndrome, sepsis or bacteremia, we speculated suPAR to have pathogenetic role in patients with severe P. falciparum. The investigation described in this thesis suggests this to be true. But a prognostic value for suPAR with AKI in this specific patient group was not confirmed

Serum levels of N-terminal proB-type natriuretic peptide in mechanically ventilated critically ill patients--relation to tidal volume size and development of acute respiratory distress syndrome

Serum levels of N-terminal proB-type natriuretic peptide (NT-proBNP) are elevated in patients acute respiratory distress syndrome (ARDS). Recent studies showed a lower incidence of acute cor pulmonale in ARDS patients ventilated with lower tidal volumes. Consequently, serum levels of NT-proBNP may be lower in these patients. We investigated the relation between serum levels of NT-proBNP and tidal volumes in critically ill patients without ARDS at the onset of mechanical ventilation. Secondary analysis of a randomized controlled trial of lower versus conventional tidal volumes in patients without ARDS. NT-pro BNP were measured in stored serum samples. Serial serum levels of NT-pro BNP were analyzed controlling for acute kidney injury, cumulative fluid balance and presence of brain injury. The primary outcome was the effect of tidal volume size on serum levels of NT-proBNP. Secondary outcome was the association with development of ARDS. Samples from 150 patients were analyzed. No relation was found between serum levels of NT-pro BNP and tidal volume size. However, NT-proBNP levels were increasing in patients who developed ARDS. In addition, higher levels were observed in patients with acute kidney injury, and in patients with a more positive cumulative fluid balance. Serum levels of NT-proBNP are independent of tidal volume size, but are increasing in patients who develop ARD

Serum cystatin C-A useful endogenous marker of renal function in intensive care unit patients at risk for or with acute renal failure?

Critically ill patients are at high risk for developing acute renal failure (ARF). The prevention of ARF is of outmost importance in order to improve the increased morbidity and mortality associated with ARF. Unfortunately, there is lack of adequate endogenous markers that can identify renal dysfunction early - this hampers timely application of measures to prevent further renal damage. The use of exogenous markers of renal function is not only time-consuming but also expensive, and therefore can not be used on a regular basis in the intensive care unit. Both the presently used endogenous and exogenous markers are not reliable during continuous renal replacement therapy (CRRT) because these markers are removed by the therapy itself impeding early detection of recovering of renal function. Cystatin C has been proposed as an alternative endogenous marker of renal function for more than 15 years. In this manuscript we review the literature on the role of cystatin C as marker for renal function, focusing on the critically ill patient. Serum cystatin C concentrations have been found to relate to renal impairment and suggest that cystatin C is more sensitive to detect mild decreases in GFR. Cystatin C could be an important tool both to recognize early renal dysfunction and to identify renal recovery while on CRRT in the critically ill patient, however, we are in need of more studie

Systemic and urinary neutrophil gelatinase-associated lipocalins are poor predictors of acute kidney injury in unselected critically ill patients

Background. Neutrophil gelatinase-associated lipocalin (NGAL) in serum and urine have been suggested as potential early predictive biological markers of acute kidney injury (AKI) in selected critically ill patients. Methods. We performed a secondary analysis of a multicenter prospective observational cohort study of unselected critically ill patients. Results. The analysis included 140 patients, including 57 patients who did not develop AKI, 31 patients who developed AKI, and 52 patients with AKI on admission to the ICU. Levels of sNGAL and uNGAL on non-AKI days were significantly lower compared to levels of sNGAL on RIFLE(RISK) days, RIFLE(INJURY) days, and RIFLE(FAILURE) days. The AUC of sNGAL for predicting AKI was low: 0.45 (95% confidence interval (CI) 0.27-0.63) and 0.53 (CI 0.38-0.67), 2 days and 1 day before development of AKI, respectively. The AUC of uNGAL for predicting AKI was also low: 0.48 (CI 0.33-0.62) and 0.48 (CI 0.33-0.62), 2 days and 1 day before development of AKI, respectively. AUC of sNGAL and uNGAL for the prediction of renal replacement therapy requirement was 0.47 (CI 0.37-0.58) and 0.26 (CI 0.03-0.50). Conclusions. In unselected critically ill patients, sNGAL and uNGAL are poor predictors of AKI or RR