[Prevention of acute kidney injury in critically ill patients : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]

[Mechanisms of action and clinical application of diuretics in intensive care medicine]

The paired kidneys play a significant role in the human body due to the multitude of physiological tasks. Complex biochemical processes keep the sensitive electrolyte and water balance stable and thus ensure the organism's ability to adapt to exogenous and endogenous factors, which is essential for survival. The drug class of diuretics includes substances with very differing pharmacological characteristics. The functioning of the nephron is therefore indispensable for a deeper understanding of the pharmacodynamics, pharmacokinetics and side effect profile of diuretics. In the treatment of acute heart failure with pulmonary congestion, certain diuretics represent an important therapeutic option to counteract hypervolemia and thus an increase in preload. According to current data, diuretics have no proven benefits in the treatment or prevention of acute kidney injury but they can counteract hypervolemia and under certain conditions even reduce the use of renal replacement procedures.

[Acute kidney injury and COVID-19: lung-kidney crosstalk during severe inflammation]

Eine mit der Coronaviruserkrankung 2019 (COVID-19) assoziierte Nierenschädigung ist vor allem bei Intensivpatient:innen ein häufiges Phänomen. Das Virus selbst dürfte im Sinne eines direkten Befalls der Niere nur in geringem Ausmaß eine Rolle spielen, die mit einer schweren COVID-19-Erkrankungen assoziierte pathologische Entzündungsreaktion dagegen sehr wohl. Einen wesentlichen Einfluss haben die Folgen der invasiven Beatmung und das durch COVID-19 verursachte Acute Respiratory Distress Syndrome (ARDS). Hohe Beatmungsdrücke wirken sich negativ auf die Nierenperfusion aus und können so zur Entstehung einer AKI beitragen. Die durch das ARDS verursachte Entzündungsreaktion sowie die für COVID-19 typische endotheliale Dysfunktion in Kombination mit einer Hyperkoagulabilität sind weitere Faktoren, die die Nierenfunktion negativ beeinflussen können.

[Prevention of acute kidney injury]

Acute kidney injury contributes significantly to morbidity and mortality in hospitalized patients and is a common complication in the intensive care unit. Identification of patients at risk, elimination of modifiable risk factors and initiation of recommended preventive measures are the main cornerstones to prevent the onset and progression of acute kidney injury. Clinical and biomarker-based risk scores can help assess AKI-risk in specific patient populations. To date, there is no approved clinically effective drug to prevent AKI. Current guidelines suggest preventive care bundles that include optimizing volume status and renal perfusion by improving mean arterial pressure and using vasopressors, mainly norepinephrine. In addition, avoidance of volume overload and the targeted use of diuretics to achieve euvolemia are recommended. Nephrotoxic drugs require a critical risk-benefit assessment and therapeutic drug monitoring when appropriate. Contrast imaging should not be withheld from patients at risk of AKI when indicated but contrast medium should be limited to the smallest possible volume. Finally, recommendations include maintenance of normoglycemia and other measures to optimize organ function in specific patient populations.

AKI Epidemiology and Outcomes: A Retrospective Cohort Study from the Prenephrology Era

BACKGROUND

Acute kidney injury substantially worsens the prognosis of hospitalized patients. The Brandenburg Medical School was founded in 2014, and a nephrology section was opened in summer 2017. The aim of the study was to analyze AKI epidemiology and outcomes in one of two university hospitals belonging to the medical school. The period of interest dated from January to December 2015.

METHODS

The investigation was designed as a single-center, retrospective cohort study at the Brandenburg Hospital of the Brandenburg Medical School. All in-hospital patients treated between January and the end of December 2015 were included. AKI was defined as specified in the 2012 published KDIGO criteria (criteria 1 and 2). Four parameters were evaluated in particular: AKI incidence, in-hospital mortality, frequency of renal replacement therapy, and renal recovery during the stay at the hospital.

RESULTS

A total number of 5,300 patients were included in the analysis. AKI was diagnosed in 490 subjects (10.1%). The in-hospital mortality was 26%. The following conditions/parameters significantly differed between survivors (s) and nonsurviving (ns) subjects: duration of in-hospital treatment (s > ns), AKI onset (outpatient vs. in-hospital) (outpatient in s > ns), dialysis due to AKI (s < ns), vasopressor administration (s < ns), and invasive ventilation (s < ns). 5.6% received dialysis therapy, and renal recovery occurred in 31% of all surviving AKI subjects.

CONCLUSION

Both, the AKI incidence and the frequency of dialysis were lower than reported in the literature. However, fewer subjects recovered from AKI. These discrepant findings possibly result from the lack of prehospitalization creatinine values, the lack of follow-up data, and a generally lower awareness for the need to perform renal replacement therapy in AKI.

Impact of urgent coronary artery bypass grafting on acute kidney injury : A matched cohort study

OBJECTIVES

There is limited knowledge regarding the specific interrelationships between urgent coronary artery bypass graft (U-CABG) surgery and postoperative acute kidney injury (AKI). We aimed to (1) analyze the impact of urgent CABG (U-CABG) on the incidence and severity of postoperative AKI, (2) estimate the influence of AKI after U‑CABG or elective CABG (E-CABG) on mortality and (3) identify risk factors for AKI depending on the urgency of operation.

RESULTS

U‑CABG patients showed a higher incidence of AKI (49.8% vs. E‑CABG: 39.7%; p = 0.026), especially for higher AKI stages 2 + 3. In-hospital mortality was higher in U‑CABG patients (12.6%) compared to E‑CABG patients (2.3%; p < 0.001). The impact of AKI on mortality did not differ, but showed a strong coherency between higher AKI stages (2 + 3) and mortality (stage 1: OR 2.409, 95% CI 1.017-5.706; p = 0.046 vs. stage 2 + 3: OR 5.577; 95% CI 2.033-15.3; p = 0.001). Univariate logistic regression analysis revealed that preoperative renal impairment, peripheral vascular disease and transfusion of more than two red blood cell concentrates were predictors for postoperative AKI in both groups.

CONCLUSIONS

U‑CABG is a risk factor for postoperative AKI and even "mild" AKI leads to a significantly higher mortality. Hence, the prevention of modifiable risk factors might reduce the incidence of postoperative AKI and thus improve outcome.

[Geriatric intensive care : Consensus paper of DGIIN, DIVI, DGAI, DGGG, ÖGGG, ÖGIAIN, DGP, DGEM, DGD, DGNI, DGIM, DGKliPha and DGG]

The proportion of elderly, frail, and multimorbid people has increased dramatically in recent decades resulting from demographic changes and will further increase, which will impact acute medical care. Prospective, randomized studies on geriatric intensive care are still lacking. There are also no international or national recommendations regarding the management of critically ill elderly patients. Based on an expert opinion, this consensus paper provides 16 statements that should be considered when dealing with geriatric critical care patients.

Etiology and Management of Acute Metabolic Acidosis: An Update

BACKGROUND

The etiology of acute metabolic acidosis (aMA) is heterogeneous, and the consequences are potentially life-threatening. The aim of this article was to summarize the causes and management of aMA from a clinician's perspective.

SUMMARY

We performed a systematic search on PubMed, applying the following search terms: "acute metabolic acidosis," "lactic acidosis," "metformin" AND "acidosis," "unbalanced solutions" AND "acidosis," "bicarbonate" AND "acidosis" AND "outcome," "acute metabolic acidosis" AND "management," and "acute metabolic acidosis" AND "renal replacement therapy (RRT)/dialysis." The literature search did not consider diabetic ketoacidosis at all. Lactic acidosis evolves from various conditions, either with or without systemic hypoxia. The incidence of metformin-associated aMA is actually quite low. Unbalanced electrolyte preparations can induce hyperchloremic aMA. The latter potentially worsens kidney-related outcome parameters. Nevertheless, prospective and controlled data are missing at the moment. Recently, bicarbonate has been shown to improve clinically relevant endpoints in the critically ill, even if higher pH values (>7.3) are targeted. New therapeutics for aMA control are under development, since bicarbonate treatment can induce serious side effects. Key Messages: aMA is a frequent and potentially life-threatening complication of various conditions. Lactic acidosis might occur even in the absence of systemic hypoxia. The incidence of metformin-associated aMA is comparably low. Unbalanced electrolyte solutions induce hyperchloremic aMA, which most likely worsens the renal prognosis of critically ill patients. Bicarbonate, although potentially deleterious due to increased carbon dioxide production with subsequent intracellular acidosis, improves kidney-related endpoints in the critically ill.

[Geriatric intensive care : Consensus paper of DGIIN, DIVI, DGAI, DGGG, ÖGGG, ÖGIAIN, DGP, DGEM, DGD, DGNI, DGIM, DGKliPha and DGG]

The proportion of elderly, frail, and multimorbid people has increased dramatically in recent decades resulting from demographic changes and will further increase, which will impact acute medical care. Prospective, randomized studies on geriatric intensive care are still lacking. There are also no international or national recommendations regarding the management of critically ill elderly patients. Based on an expert opinion, this consensus paper provides 16 statements that should be considered when dealing with geriatric critical care patients.

Oliguria in critically ill patients: a narrative review

Oliguria is often observed in critically ill patients. However, different thresholds in urine output (UO) have raised discussion as to the clinical importance of a transiently reduced UO of less than 0.5 ml/kg/h lasting for at least 6 h. While some studies have demonstrated that isolated oliguria without a concomitant increase in serum creatinine is associated with higher mortality rates, different underlying pathophysiological mechanisms suggest varied clinical importance of reduced UO, as some episodes of oliguria may be fully reversible. We aim to explore the clinical relevance of oliguria in critically ill patients and propose a clinical pathway for the diagnostic and therapeutic management of an oliguric, critically ill patient.

[Interactions between lung and kidney in the critically ill]

Interactions between lung and kidney can significantly affect the course of acute diseases, a phenomenon that was first observed in the 1950s by describing pulmonary dysfunction in uremic patients. From animal experiments there is ample evidence for remote lung injury following acute kidney injury (AKI), with an increased risk for the development of pulmonary edema and acute respiratory distress syndrome (ARDS). Coincident ARDS and AKI are associated with higher rates of intubation and mechanical ventilation, significantly prolonged weaning from mechanical ventilation and increased mortality. On the other hand, acute lung diseases and mechanical ventilation can promote the development of AKI and are associated with increased mortality when AKI is also present. These bidirectional interactions may include hemodynamic adverse effects during mechanical ventilation or volume overload as well as the release or decreased clearance and metabolism of proinflammatory mediators (e.g., interleukin-6 and tumor necrosis factor-α), which may induce and aggravate distant organ injury. The aim of this work is to examine the interactions between lung and the kidney in critically ill patients, as well as discuss potential preventive approaches.