Critical illness among patients experiencing homelessness: a retrospective cohort study.

PURPOSE: To understand the epidemiology and healthcare use of critically ill patients experiencing homelessness compared to critically ill patients with stable housing. METHODS: This retrospective population-based cohort study included adults admitted to any ICU in Alberta, Canada, for a 3-year period. Administrative and clinical data from the hospital, ICU and emergency department were used to examine healthcare resource use (processes of care, ICU and hospital length of stay, hospital readmission and emergency room visits). Regression was used to quantify differences in healthcare use by housing status. RESULTS: 2.3% (n = 1086) of patients admitted to the ICU were experiencing homelessness; these patients were younger, more commonly admitted for medical reasons and had fewer comorbidities compared to those with stable housing. Processes of care in the ICU were mostly similar, but healthcare use after ICU was different; patients experiencing homelessness who survived their index hospitalization were more than twice as likely to have a visit to the emergency department (OR = 2.3 times, 95% CI 2.0-2.6, < 0.001) or be readmitted to hospital (OR = 2.1, 95% CI 1.8-2.4, p < 0.001) within 30 days, and stayed 10.1 days longer in hospital (95% CI 8.6-11.6, p < 0.001), compared with those who have stable housing. CONCLUSIONS: Patients experiencing homelessness have different characteristics at ICU admission and have similar processes of care in ICU, but their subsequent use of healthcare resources was higher than patients with stable housing. These findings can inform strategies to prepare patients experiencing homelessness for discharge from the ICU to reduce healthcare resource use after critical illness.

Timing of continuous renal replacement therapy in severe acute kidney injury patients with fluid overload: A retrospective cohort study.

PURPOSE: We aimed to evaluate the association of early versus late initiation of Continuous renal replacement therapy (CRRT) with mortality in patients with fluid overload. METHODS: This was a retrospective cohort study of patients with fluid overload (FO) treated with CRRT due to severe acute kidney injury (AKI) between January 2015 and December 2017 in a mixed medical intensive care unit of a teaching hospital in Beijing, China. Patients were divided into early (≤15 h) and late (>15 h) groups based on the median time from ICU admission to CRRT initiation. The primary outcome was all-cause mortality at day 60. Multivariable Cox model analysis was used for analysis. RESULTS: The study patients were male predominant (84/150) with a mean age of 64.8 ± 16.7 years. The median FO value before CRRT initiation was 10.1% [6.2-16.1%]. The 60-day mortality rates in the early vs the late CRRT groups were 53.9% and 73%, respectively. On multivariable Cox modelling, the late initiation of CRRT was independently associated with an increased risk of death at 60 days (HR 1.75, 95% CI 1.11-2.74, p = 0.015). CONCLUSIONS: Early initiation of CRRT was independently associated with survival benefits in severe AKI patients with fluid overload.

The furosemide stress test for prediction of worsening acute kidney injury in critically ill patients: A multicenter, prospective, observational study.

PURPOSE: To validate the furosemide stress test (FST) for predicting the progression of acute kidney injury (AKI). MATERIALS AND METHODS: We performed a multicenter, prospective, observational study in patients with stage I or II AKI. The FST (1 mg/kg for loop diuretic naïve patients and 1.5 mg/kg in patients previously exposed to loop diuretics) was administered. Subsequent urinary flow rate (UFR) recorded and predictive ability of urinary output was measured by the area under the curve receiver operatic characteristics (AuROC). Primary outcome was progression to Stage III AKI. Secondary outcomes included in-hospital mortality and adverse events. RESULTS: We studied 92 critically ill patients. 23 patients progressed to stage III AKI and had significantly lower UFR (p < 0.0001). The UFR during the first 2 h was most predictive of progression to stage III AKI (AuROC = 0.87), with an ideal cut-off of less than 200mls, with a sensitivity of 73.9% and specificity of 90.0%. CONCLUSION: In ICU patients without severe CKD with mild AKI, a UFR of less than 200mls in the first 2 h after an FST is predictive of progression to stage III AKI. Future studies should focus on incorporating a FST as part of a clinical decision tool for further management of critically ill patients with AKI.

Venous Thromboembolism Prophylaxis in Neurocritical Care Patients: Are Current Practices, Best Practices?

BACKGROUND/OBJECTIVES: Venous thromboembolism (VTE) is a leading cause of preventable, in-hospital deaths; critically ill patients have a higher risk. Effective and efficient strategies to prevent VTE exist; however, neurocritical care patients present unique challenges due to competing risk of bleeding. The objective of this study was to examine current VTE prophylaxis practices among neurocritical care patients, concordance with guideline-recommended care, and the association with clinical outcomes. METHODS: This retrospective cohort study of patients admitted to ten adult, medical-surgical and neurological intensive care units (ICUs) in nine hospitals between 2014 and 2017 using administrative and clinical data. Neurocritical care patients were classified based on the primary admission diagnosis. Concordance with guideline-recommended care was evaluated using recommendations from recent guidelines. RESULTS: 20.0% of 23,191 patients were classified as neurocritical care. Among neurocritical care patients, pharmacological VTE prophylaxis was administered on 60.9% of all ICU days, mechanical VTE prophylaxis on 46.9%, and no VTE prophylaxis on 12.2% of all ICU days. Type of VTE prophylaxis was associated with sex, neurological diagnosis, and invasive neurological monitoring. Fifty-six percentage of ICU days were guideline concordant but concordance varied by recommendation (range 6-100%) and by type of VTE prophylaxis recommended (p = 0.05); among patients where guidelines recommended use of pharmacologic prophylaxis, care was concordant 26.6% of ICU days, whereas for mechanical prophylaxis it was concordant 80.5% of ICU days. There was an overall improvement in guideline concordance on 2.3% of ICU days after the publication of the Society of Neurocritical Care guideline (p = 0.005). CONCLUSIONS: Neurocritical care patients commonly receive mechanical VTE prophylaxis despite guidelines recommending the use of pharmacological VTE prophylaxis. Our findings suggest uncertainty around best VTE prophylaxis practices for neurocritical care patients remains.

Association of protein intake with the outcomes of critically ill patients: a post hoc analysis of the PermiT trial.

Background: The optimal amount of protein intake in critically ill patients is uncertain. Objective: In this post hoc analysis of the PermiT (Permissive Underfeeding vs. Target Enteral Feeding in Adult Critically Ill Patients) trial, we tested the hypothesis that higher total protein intake was associated with lower 90-d mortality and improved protein biomarkers in critically ill patients. Design: In this post hoc analysis of the PermiT trial, we included patients who received enteral feeding for ≥3 consecutive days. Using the median protein intake of the cohort as a cutoff, patients were categorized into 2 groups: a higher-protein group (>0.80 g · kg-1 · d-1) and a lower-protein group (≤0.80 g · kg-1 · d-1). We developed a propensity score for receiving higher protein. Primary outcome was 90-d mortality. We also compared serial values of prealbumin, transferrin, 24-h urinary nitrogen, and 24-h nitrogen balance on days 1, 7, and 14. Results: Among the 729 patients included in this analysis, the average protein intake was 0.8 ± 0.3 g · kg-1 · d-1 [1.0 ± 0.2 g · kg-1 · d-1 in the higher-protein group (n = 365) and 0.6 ± 0.2 g · kg-1 · d-1 in the lower-protein group (n = 364); P < 0.0001]. There was no difference in 90-d mortality between the 2 groups [88/364 (24.2%) compared with 94/363 (25.9%), propensity score-adjusted OR: 0.80; 95% CI: 0.56, 1.16; P = 0.24]. Higher protein intake was associated with an increase in 24-h urea nitrogen excretion compared with lower protein intake, but without a significant change in prealbumin, transferrin, or 24-h nitrogen balance. Conclusions: In the PermiT trial, a moderate difference in protein intake was not associated with lower mortality. Higher protein intake was associated with increased nitrogen excretion in the urine without a corresponding change in prealbumin, transferrin, or nitrogen balance. Protein intake needs to be tested in adequately powered randomized controlled trials targeting larger differences in protein intake in high-risk populations.

Polymyxin B hemoperfusion in endotoxemic septic shock patients without extreme endotoxemia: a post hoc analysis of the EUPHRATES trial.

PURPOSE: The EUPHRATES trial examined the impact of polymyxin B hemoperfusion (PMX) on mortality in patients with septic shock and endotoxemia, defined as EAA ≥ 0.60. No difference was found in 28-day all-cause mortality. However, the trial showed that in some patients with septic shock the burden of endotoxin activity was extreme (EAA ≥ 0.9). In a post hoc analysis, we evaluated the impact of PMX use in patients with septic shock and endotoxin activity measured between 0.6-0.89. METHODS: Post-hoc analysis of the EUPHRATES trial for the 194 patients with EAA ≥ 0.6-0.89 who completed two treatments (PMX or sham). The primary end point was mortality at 28 days adjusted for APACHE II score and baseline mean arterial pressure (MAP). Additional end points included changes in MAP, cumulative vasopressor index (CVI), median EAA reduction, ventilator-free days (VFD), dialysis-free days (DFD) and hospital length of stay. Subpopulations analyzed were site and type of infection and those with norepinephrine dose > 0.1 mcg/kg/min at baseline. RESULTS: At 28 days, 23 patients of 88 (26.1%) in the PMX group died versus 39 of 106 (36.8%) in the sham group [risk difference 10.7%, OR 0.52, 95% CI (0.27, 0.99), P = 0.047]. When unadjusted for baseline variables, P = 0.11. The 28-day survival time in the PMX group was longer than for the sham group [HR 0.56 (95% CI 0.33, 0.95) P = 0.03]. PMX treatment compared with sham showed greater change in MAP [median (IQR) 8 mmHg (- 0.5, 19.5) vs. 4 mmHg (- 4.0, 11) P = 0.04] and VFD [median (IQR) 20 days (0.5, 23.5) vs. 6 days (0, 20), P = 0.004]. There were no significant differences in other end points. There was a significant difference in mortality in PMX-treated patients with no bacterial growth on culture [PMX, 6/30 (20%) vs. sham, 13/31 (41.9%), P = 0.005]. The median EAA change in the population was - 12.9% (range: increase 49.2%-reduction 86.3%). The mortality in the above median EAA change group was PMX: 6/38 (15.7%) vs. sham 15/49 (30.6%), P = 0.08. CONCLUSIONS: These hypothesis-generating results, based on an exploratory post hoc analysis of the EUPHRATES trial, suggest measurable responses in patients with septic shock and an EAA ≥ 0.6 to 0.89 on changes in mean arterial pressure, ventilator-free days and mortality. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01046669. Funding Spectral Medical Incorporated.

Implementing Frailty Measures in the Canadian Healthcare System.

Canadian healthcare is changing to include individuals living with frailty, but frailty must be better operationalized and better framed by sound data standards and policy. Frailty results from deficit accumulation in multiple body systems, with exaggerated vulnerability to external stressors. A growing consensus on defining frailty sets the stage for consensus on operationalization and widespread implementation in care settings. Frailty measurement is not yet integrated into daily clinical practice in Canada. Here, we will present how this integration might occur. We hope to demonstrate that implementation must appeal to inter-professional practice needs in different settings or circumstances. In some settings, methods for frailty case finding are expected to evolve as deemed to be most appropriate to the front-line users. In this "hands-off" approach, care providers, supported by emerging knowledge translation on frailty operationalization, would be informed by their setting and local practices to establish patterns of ad hoc case finding and component definition of frailty. This more nimble case finding strategy would be opportunistic, and would appeal to expert clinicians and self-directed teams who emphasize an individualized health care experience for their patients. In other settings, we can shape frailty case finding by building care algorithms around existing standardized practices and data repositories, leading to a systematic application of frailty measures and a more coordinated process of component definition and care protocols. Here, recommended instruments and data standards must be endorsed by health networks locally, provincially and nationally. The interRAI suite of assessment instruments has pan-Canadian standards in place and its pervasiveness makes it the most obvious starting point, especially in home care and long-term care. We anticipate the evolution of an integrated model informed by stakeholders and settings, where policy makers focus on system supports for frailty case finding, while front-line clinicians use case finding strategies to pinpoint and act on key frailty components.

The prediction of postoperative stroke or death in patients with preoperative atrial fibrillation undergoing non-cardiac surgery: a VISION sub-study.

BACKGROUND: The optimal means of pre-operative risk stratification in patients with atrial fibrillation (AF) is uncertain. OBJECTIVE: To examine the accuracy of AF thromboembolic risk models (the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores) for predicting 30-day stroke and/or all-cause mortality after non-cardiac surgery in patients with preoperative AF, and to compare these risk scores with the Revised Cardiac Risk Index (RCRI). PATIENTS/METHODS: A multicentre (8 countries, 2007-2011) prospective cohort study of patients ≥ 45 years of age undergoing inpatient non-cardiac surgery, who were followed until 30 days after surgery. We calculated c-statistics for each risk prediction model and net reclassification improvements (NRIs) compared with the RCRI. RESULTS: The 961 patients with preoperative AF were at higher risk of any cardiovascular event in the 30 days postoperatively compared with the 13 001 patients without AF: 26.6% vs. 9.0%; adjusted odds ratio, 1.58; 95% confidence interval [CI], 1.33-1.88. All thromboembolic risk scores predicted postoperative death just as well as the RCRI (with c-indices between 0.67 and 0.72). Compared with the RCRI (which had a c-index of 0.64 for 30-day stroke/death), the CHADS2 (c-index, 0.67; NRI, 0.31; 95% CI, 0.02-0.61) significantly improved postoperative stroke/mortality risk prediction, largely due to improved discrimination of patients who did not subsequently have an event. CONCLUSIONS: In AF patients, the three thromboembolic risk scores performed similarly to the RCRI in predicting death within 30 days and the CHADS2 score was the best predictor of postoperative stroke/death regardless of type of surgery.

The effect of three different miniaturized blood purification devices on plasma cytokine concentration in an ex vivo model of endotoxinemia.

PURPOSE: A novel type of adsorptive plasma filtering device (ETX-A) capable of removing endotoxin from blood in a single step has recently been developed using nanotechnology. METHODS: In a miniaturized, ex vivo model of extracorporeal circuits, we tested the capacity to reduce plasma cytokine concentration of ETX-A filters in comparison to standard high-flux (HF) filters, high cut-off (HCO) filters and a control. Blood from six healthy volunteers was spiked with endotoxin and then circulated through closed (ETX-A, control) or open (HF, HCO) circuits. Blood flow was set at 16 ml/min and filtration flow at 1 ml/min. Samples for measurement of IL-1ra and IL-6 were taken at baseline and at 4 hours. RESULTS: Compared to control (703.3 [850.6] pg/mL), in HCO (383.5 [1144.1] pg/mL) and ETX-A (490.1 [683.2] pg/mL) filters, plasma IL-1ra pooled pre- and postfilter concentrations were lower at the end of the experiment (P=0.002; P=0.050, respectively) whereas, in standard HF filters, IL-1ra concentration was higher than control. HCO showed a trend toward a reduced relative increase in IL-6 concentration from commencement to end of experiment compared to control (P=0.07). After pooling end-of-experiment plasma cytokine values of novel blood purification devices, we found HCO + ETX-A superior to H with regard to reduction of IL-1ra (-27.0 [-20.5]% vs. 8.1 [18.9]%; p<0.001) and IL-6 (-18.0 [38.3]% vs. -1.1 [24.3]%; P=0.050) compared to control. CONCLUSIONS: HCO and ETX-A appeared to significantly reduce plasma IL-1ra and, when combined, plasma IL-6 concentration as well. It appears desirable to manufacture full-size blood purification devices using this technology and to explore their effect on cytokine removal.

When should renal replacement therapy for acute kidney injury be initiated and discontinued?

BACKGROUND: Critically ill patients with acute kidney injury (AKI) are at high risk for death and frequently require initiation of renal replacement therapy (RRT). There is wide variation in clinical practice on the indications for and timing of initiation and discontinuation of RRT. Numerous clinical and biochemical factors (i.e. uremic, metabolic, fluid balance) have been used; however, at present there is no consensus to guide clinicians on the most favorable time to initiate and/or discontinue RRT to optimize patient outcomes. METHODS: In this review, we appraise the available clinical studies that have assessed timing of initiation and/or discontinuation of RRT for critically ill patients with AKI. 'Timing' of initiation has been variably defined including use of conventional biomarkers (i.e. serum urea and creatinine), urine output, fluid balance, and time relative to intensive care unit admission. CONCLUSIONS: Numerous studies consistently point toward a survival benefit to early initiation of RRT; however, there is a paucity of high-quality randomized trials. If early RRT is associated with clinical benefit, it remains uncertain whether this is attributable to more rapid metabolic/uremic control, management of fluid balance or a combination of clinical factors. In addition, timing of RRT initiation is likely context-specific and varies by clinical factors and/or etiology of AKI. There is also little data to accurately distinguish in advance between the injured kidney that will need extracorporeal renal support and one that retains capacity for early recovery. Fewer studies have evaluated the process of weaning of RRT or ideal methods to predict sufficient recovery to avoid re-initiation. Longer duration of RRT support, higher illness severity and lower urine output (independent of diuretic therapy) have all predicted need for re-initiation. Additional investigations on these issues are clearly warranted and urgently needed.

Acetaminophen-induced acute liver failure treated with single-pass albumin dialysis: report of a case.

BACKGROUND: Acetaminophen (paracetamol) overdose is a leading cause of acute liver failure (ALF). When patients fulfill the King's College criteria for acetaminophen-induced ALF (AALF), they have a poor prognosis for survival without liver transplantation. Recent advances in artificial liver support have used albumin as a binding and scavenging molecule in ALF. One method, single-pass albumin dialysis (SPAD), involves dialyzing blood against an albumin-containing solution across a high-flux membrane to remove albumin-bound toxins. Herein, we describe our protocol for SPAD and report its use in a case of AALF as a bridge to native liver recovery. CASE: A 41-year-old female with no documented history of liver disease presented with acute acetaminophen toxicity and developed hepatic encephalopathy, coagulopathy and lactic acidosis. The patient met King's College criteria for liver transplantation, based on pH and INR, but was deemed not suitable as a candidate due to psychosocial comorbidities. On day 3 of her ICU admission, she received the first of five consecutive daily runs (total ~77 hours) of SPAD. The patient's course was complicated by cerebral edema requiring mannitol. She was extubated on day 11 and transferred to the ward by day 13. At ICU discharge, her liver function (INR 1.9, bilirubin 435 mmol/L) and kidney function were recovering. She did not have any long-term neurological sequelae. By hospital discharge (day 46) her native liver function had recovered with a bilirubin <100mmol/L. CONCLUSION: We describe a case of a patient with acetaminophen-induced acute liver failure who was successfully bridged to spontaneous native liver recovery as a result of SPAD treatment. In patients with ALF, SPAD may be an additional intervention for temporary extracorporeal support. Further investigation in larger prospective studies is warranted.

Outcome comparisons of intermittent and continuous therapies in acute kidney injury: what do they mean?

Despite the fact that no new clinical outcome studies comparing intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT) for acute kidney injury (AKI) have been published in the past year, two meta-analyses addressing the topic (Bagshaw et al, Crit Care Med 2008; 36: 610-7, and Pannu et al, JAMA 2008; 299: 793-805) have been published recently. With respect to randomized controlled trials (RCTs), there was a substantial overlap between the studies considered in the analysis by Bagshaw et al and those considered in the analysis by Pannu et al. Although neither metaanalysis showed a benefit for either modality with respect to mortality or renal recovery, the two publications offered vastly different conclusions. Bagshaw et al concluded it is impossible to make any definitive recommendations about dialysis modality choice in AKI because previous studies were not adequately powered and failed to standardize for treatment dose. On the other hand, because the metaanalysis of Pannu et al demonstrated equivalent patient outcomes, and in light of the lower costs of IHD, they suggested that alternate-day hemodialysis should become the preferred therapy in many critically ill patients. As the clinical practice recommendations made by Pannu and colleagues have very important implications, we believe their analysis should be critically assessed. In this review, the weaknesses of the RCTs considered in the meta-analysis by Pannu et al are presented. Furthermore, the assumption by Pannu et al that IHD is associated with lower costs than CRRT is challenged, as they did not consider adequately both the short-term and long-term costs associated with the dialytic management of AKI patients. Based on our critical analysis, we believe the AKI dialytic treatment approach recommended by the JAMA investigators (Pannu et al) is not supported by the aggregate of the available clinical outcome data and, therefore, remains highly controversial. We would like to join with others in the AKI field by strongly recommending that investigators and other clinicians stop trying to make conclusive determinations about dialysis modalities when robust supportive data simply are not available. Instead of additional intermodality comparisons, the focus of future clinical research should be toward generating high-quality data on intramodality interventions, such as treatment dose and timing of treatment initiation. In this regard, at least for CRRT, we anxiously await the results of the ongoing RCTs evaluating the effect of CRRT dose on patient outcome.

Fluid balance error in continuous renal replacement therapy: a technical note.

BACKGROUND: The reliability and safety of continuous renal replacement therapy (CRRT) machines have improved, yet there still remains the potential for fluid balance errors to occur during treatment. METHODS: In vitro testing of two Kimal Hygieia CRRT machines (Plus and Ultima) was performed. Normal saline to simulate the blood circuit and standard bicarbonate-based fluid for replacement were used. All tests were performed in CVVH mode at four ultrafiltration (UF) rates. The testing was based on creation of a voluntary fluid balance error by clamping the line that fills the replacement fluid chamber to stop flow to the (simulated) patient. The time to alarms and fluid balance errors were recorded. The alarms were overridden and the accumulated fluid balance error allowed by the machine was determined. RESULTS: The alarm occurred approximately 1 minute after the replacement fluid line was clamped at all UF rates. There was no limit to the number of times the alarm could be overridden and the accumulated negative fluid balance was proportional to the prescribed UF rate. After the replacement fluid chamber was allowed to re-fill, the machine attempted to correct the fluid deficit and consistently delivered excess fluid to generate a positive fluid balance error. CONCLUSIONS: The Hygieia machines appear designed with appropriate alarm and safety features. However, simulated fluid balance errors raise caution for operators. Clinicians and nurses need to understand the clinical implications of alarm overrides. Fluid balance errors caused by failure to acknowledge and correct replacement fluid failure alarms may cause harm to patients.

Ideal determinants for the initiation of renal replacement therapy: timing, metabolic threshold or fluid balance?

Patients with acute kidney injury (AKI) frequently require initiation of renal replacement therapy (RRT). Currently there is considerable variation worldwide on the indications for and timing of initiation and discontinuation of RRT for AKI. Numerous parameters for metabolic, solute and fluid control are generally utilized to guide the initiation and discontinuation of RRT. However, there are currently no standards in this field.

Renal recovery after severe acute renal failure.

BACKGROUND: There is limited information about renal recovery to independence from renal replacement therapy (RRT) and about factors associated with its occurrence after severe acute renal failure (ARF). METHODS: We conducted a population-based surveillance among all adult residents of the Calgary Health Region surviving ICU admission from May 1, 1999 to April 30, 2002. The primary objective was to determine the rate of and the factors associated with 90-day survival and recovery to independence from RRT in critically ill patients with severe ARF. RESULTS: At 90 days, 96 patients (40%) were alive. Of these, 72% were RRT independent with most (87%) requiring <4 weeks to recover. Prior to RRT, the median (IQR) serum creatinine and mean (SD) serum urea were 395 (252-517) micromol/L and 29.2 (18) mmol/L, respectively. Oliguria was present in 76%. Intermittent hemodialysis was the initial modality in 46% and continuous renal replacement therapy (CRRT) in 54%. By multivariate analysis, male sex (odds ratio (OR) 7.6, 95% CI, 2.2-27, p=0.01) and a diagnosis of septic shock (OR 3.9, 95% CI 1.02-14.5, p=0.05) were associated with an increased odds of recovery. Conversely, a higher Charlson co-morbidity index score (OR 0.71, 95% CI, 0.6-0.85, p=0.04) and a higher pre-RRT serum creatinine (OR 0.20, 95% CI, 0.05-0.80, p=0.02, p=0.02) were associated with reduced odds of recovery. Chronic kidney disease or the initial modality of RRT were not associated with recovery. CONCLUSIONS: The majority of severe ARF patients who survive their acute illness are independent of RRT by 90 days. Male sex and a diagnosis of septic shock are independently associated with recovery while a greater co-morbidity score and a higher serum creatinine prior to RRT are predictive of non-recovery.

Contrast-induced nephropathy: epidemiology and prevention.

Contrast-induced nephropathy (CIN) is a leading cause of iatrogenic acute kidney failure. Periprocedural CIN results in a greater risk of requiring renal replacement therapy, prolonged hospitalization, excessive health care costs, potential long term kidney impairment and mortality. Identified risk factors for CIN include premorbid chronic kidney disease, diabetes mellitus, congestive heart failure, critical illness and volume of administered contrast media. Prophylactic interventions for the prevention of CIN remain controversial and uncertain. In this review we critically appraise the evidence for prevention of CIN. In general, every attempt should be made to correct underlying volume depletion, discontinue potential nephrotoxins, reverse any acute kidney dysfunction or when not possible, consider delay of procedure or an alternative modality for imaging. A minimum volume of contrast media should be employed, including going left ventriculogram and performing staged procedures if applicable. There are few interventions with quality evidence for reducing the incidence of CIN. procedure hydration and the use of nonionic iso-osmolar contrast media have consistently demonstrated efficacy. For patients at high risk, there is evidence to suggest benefit with N-acetylcysteine. Clinical studies with adenosine antagonists are encouraging; however, further confirmatory trials are required. Based on the available studies, there is inadequate evidence for the routine use of hemofiltration, atrial natriuretic peptides, calcium channel blockers, or prostaglandins. There is no evidence to support prophylaxis with diuretic therapy, forced diuresis, low dose dopamine, fenoldopam, captopril, or endothelin receptor antagonists. Despite recent advances in the epidemiology, pathophysiology and natural history of CIN, few effective prophylactic or therapeutic interventions have conclusively demonstrated evidence for a reduction in CIN incidence and no therapy has proven efficacious once CIN is established.

Beliefs and behaviours of parents regarding antibiotic use by children.

OBJECTIVE: To determine parents' beliefs and behaviours about antibiotic use by their children in the ambulatory setting. DESIGN: Cross-sectional survey, where a self-administered questionnaire was completed by adult caregivers of children before the medical assessment of the child. SETTING: Three paediatric acute care settings (paediatric emergency department [PED], group paediatric practice and after hours walk-in medical clinic). POPULATION STUDIED: Adult caregivers (n=114; 76% mothers, 19% fathers and 4% other caregivers) of children brought for acute care were surveyed. MAIN RESULTS: Forty-one caregivers completed the survey in the PED, 37 in the paediatric office and 36 in the walk-in clinic. They believed that antibiotics were appropriate for ear infections (86%), pharyngitis (77%), bronchitis (49%), sinus colds (20%), cough (12%), colds (8%) and influenza (8%). Sixty-eight per cent of children had received antibiotics in the previous year. Thirteen per cent of caregivers reported previously requesting an antibiotic for their child, 18% believed a previous antibiotic prescription had been unnecessary and 19% had not complied with prescriptions in the past. Concerns about antibiotic use included antibiotic resistance (50%), harm to the immune system (40%), adverse effects (28%) and lack of efficacy (19%). CONCLUSIONS: In this population, parental knowledge and understanding of indications for antibiotics and their adverse effects were good; however, incorrect beliefs and disagreements with physicians did occur. To improve patterns of antibiotic use by children, it will be necessary to understand parents' beliefs, behaviours and information sources better so that misconceptions and disagreements with caregivers can be addressed appropriately.