Risk of de novo infection following acute kidney injury: A retrospective cohort study

Timing of Kidney Support Therapy in Acute Kidney Injury: What Are We Waiting For?

The optimal timing of kidney support therapy in critically ill patients with acute kidney injury (AKI) without life-threatening complications related to AKI is controversial. Recent multicenter, randomized, controlled studies have questioned the need for earlier initiation of therapy, despite one study showing a benefit in survival and others with no differences in mortality based on the timing of kidney support therapy initiation. These findings reflect the uncertainties in decisions to initiate kidney support therapy, which should ideally be individualized according to the patient's comorbidities, severity of illness, trajectory of kidney function, and urine output as well as requirements for fluid balance and solute removal. A delayed approach could translate into a potentially reduced burden of dialysis dependence in addition to saving health resources. However, we must ascertain what constitutes the waiting period and the benefits and risks associated with this approach. This article reviews the concept of timing of dialysis in AKI, performs a critical assessment of the most important clinical trials in this topic, discusses ongoing research and knowledge gaps, and defines key research issues to address in the future.

Risk Stratification for Targeted AKI Prevention After Surgery: Biomarkers and Bundled Interventions

Perioperative acute kidney injury (AKI) is a surgery-associated complication with increasing incidence, not only because of enhanced awareness for the diagnosis, but also as a result of the aging society with a growing number of severe comorbidities undergoing major surgical procedures. The dilemma of AKI as a global health burden lies in the discrepancy between its importance as a significant risk factor for morbidity and mortality, and the unavailability of specific therapies to modify these adverse outcomes. Thus, it is all the more important to focus management on AKI prevention, and when AKI occurs to focus on early recognition and immediate adaption of individualized care. AKI is the result of an inter-relationship between patient susceptibility and determinants of perioperative exposures. Screening for constellations of risk factors along with measurement of novel biomarkers allows for early identification of patients who are susceptible to AKI and to initiate early targeted care. Targeted care involves implementation of a bundle of interventions adapted from a consensus management guideline, and is a strategy with growing evidence of a beneficial effect on patients' short- and long-term outcomes.

Acute kidney injury and adverse outcomes of critical illness: correlation or causation?

Critically ill patients who develop acute kidney injury (AKI) are more than twice as likely to die in hospital. However, it is not clear to what extent AKI is the cause of excess mortality, or merely a correlate of illness severity. The Bradford Hill criteria for causality (plausibility, temporality, magnitude, specificity, analogy, experiment & coherence, biological gradient and consistency) were applied to assess the extent to which AKI may be causative in adverse short-term outcomes of critical illness.

Plausible mechanisms exist to explain increased risk of death after AKI, both from direct pathophysiological effects of renal dysfunction and mechanisms of organ cross-talk in multiple-organ failure. The temporal relationship between increased mortality following AKI is consistent with its pathophysiology. AKI is associated with substantially increased mortality, an association that persists after accounting for known confounders. A biological gradient exists between increasing severity of AKI and increasing short-term mortality. This graded association shares similar features to the increased mortality observed in ARDS; an analogous condition with a multifactorial aetiology. Evidence for the outcomes of AKI from retrospective cohort studies and experimental animal models is coherent however both of these forms of evidence have intrinsic biases and shortcomings. The relationship between AKI and risk of death is maintained across a range of patient ages, comorbidities and underlying diagnoses.

In conclusion many features of the relationship between AKI and short-term mortality suggest causality. Prevention and mitigation of AKI and its complications are valid targets for studies seeking to improve short-term survival in critical care.

Postoperative complications increase the risk of long-term chronic kidney disease after nephron-sparing surgery in patients with renal cancer and normal preoperative renal function

OBJECTIVES

To investigate whether postoperative complications affect long-term functional outcomes of renal patients treated with nephron-sparing surgery (NSS).

MATERIALS AND METHODS

We performed an observational study, enrolling 596 patients with preoperative normal renal function treated with NSS for clinical T1abN0M0 renal masses. Cox regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for chronic kidney disease (CKD) including as covariates age, comorbidity (scored according to the Charlson comorbidity index), hypertension, tumour size, preoperative estimated glomerular filtration rate (eGFR), eGFR < 60 mL/min/1.73 m² at discharge, and ischaemia time.

RESULTS

A total of 137 patients (23%) developed postoperative complications. At a median (interquartile range) follow-up of 53 (26-91) months, CKD risk was 19% for patients with postoperative complications and 11% for those without complications. Patients experiencing postoperative complications (HR 1.90, 95% CI 1.26-2.86) were at increased risk of developing CKD during the follow-up at multivariable analysis, after accounting for confounders.

CONCLUSIONS

Our data outline how postoperative complications might have a detrimental impact on postoperative renal function in patients submitted to NSS. Improper patient selection, increasing the risk of postoperative complications, could limit the benefit in terms of renal function brought by NSS.

Clinical Application of Pharmacokinetics: Basis for Rational Dose Selection in a Critically Ill Patient on Renal Replacement Therapy

BACKGROUND

Individualizing drug dosing regimens in critically ill patients on renal replacement therapy is a challenge to clinicians as guidelines are often imprecise and specific-validated pharmacokinetic software is unavailable.

OBJECTIVE

A case of a septic patient on hemodialysis is presented, where a quick solution for antibiotic dose adjustment based on the application of pharmacokinetic principles was found.

METHODS

The dose adjustment was made in two steps-the first step was to calculate total antibiotic clearance (using the formula: total drug clearance = dialysate flow rate × fraction of unbound drug in plasma + extrarenal clearance), and the second step was to calculate maintenance dose based on target plasma concentrations in steady-state (using the formula: maintenance dose = target plasma concentration × total drug clearance × dose interval).

RESULTS

After the doses of antibiotics were adjusted, the patient's condition gradually improved, with a drop in body temperature to normal values, a decrease in plasma levels of inflammatory parameters, and the emergence of spontaneous diuresis. The plasma concentration of vancomycin was within the recommended therapeutic range.

CONCLUSIONS

Specific pharmacokinetic software and measuring plasma concentrations of the drugs should be used for calculation of total drug clearance and dose adjustment whenever possible. However, if unavailable, basic pharmacokinetic formulas and principles could be successfully used instead to adjust the dose in critically ill patients on hemodialysis.