A narrative review of the impact of surgery and anaesthesia on acute kidney injury.

The epidemiology of peri-operative acute kidney injury varies depending on the definition, type of surgery and acute and chronic comorbidities. Haemodynamic instability, disturbance of the microcirculation, endothelial dysfunction, inflammation and tubular cell injury are the main factors contributing to the pathogenesis. There are no specific therapies. The most effective strategies to protect renal function during the peri-operative period are: the avoidance of nephrotoxic insults; optimisation of haemodynamics; prevention of hypotension; and meticulous fluid management, including avoidance of both hypovolaemia and hypervolaemia. Peri-operative acute kidney injury is associated with an increased risk of short- and long-term postoperative complications, including a longer stay in hospital, development of premature chronic kidney disease and increased mortality. Resource utilisation and healthcare costs are also higher. In future, the development of advanced clinical prediction scores, new imaging and monitoring techniques and the application of new biomarkers for acute kidney injury have the prospect of identifying acute kidney injury earlier and allowing a more personalised management approach with the aim of reducing the global burden of acute kidney injury.

[Perioperative acute kidney injury]. / Perioperative akute Nierenschädigung.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication in the perioperative period and is associated with a high morbidity and mortality. AKI is an independent risk factor for adverse outcome. The Kidney Disease: Improving Global Outcome (KDIGO) guidelines define AKI based on increases in serum creatinine and/or urinary output. Since there is no causal therapy available, early detection and timely implementation of preventive measures are of particular importance. OBJECTIVE: This article gives an overview of the disease picture of perioperative AKI. The recommendations on diagnostics, prevention and treatment are presented. METHODS: The available evidence is summarized based on the currently available literature. RESULTS: New renal biomarkers demonstrate kidney stress and are able to make an early prediction of the development of AKI. The implementation of the KDIGO bundles (discontinuation of all nephrotoxic medications, optimization of the volume status and perfusion pressure, consideration of an extended functional hemodynamic monitoring, close monitoring of serum creatinine concentration and urine output, avoidance of hyperglycemia and consideration of alternatives to radiocontrast agents) and remote ischemic preconditioning have shown a significant reduction in the incidence of AKI in high-risk patients. CONCLUSION: For timely diagnosis and prevention of AKI the recommendations for action of the KDIGO guidelines should be implemented. High-risk patients should be detected early in the perioperative period in order to be able to initiate preemptive strategies in a timely manner.

Polyesteramide-derived nonwovens as innovative degradable matrices support preadipocyte adhesion, proliferation, and differentiation.

Extended soft tissue defects resulting from injuries or tumor resections are still an unresolved problem in plastic and reconstructive surgery because adequate reconstruction is difficult. Immature adipogenic precursor cells, called preadipocytes, which are located between mature adipocytes in adipose tissue, represent a powerful tool for soft tissue engineering because of their ability to proliferate and differentiate into adipose tissue after transplantation. In previous studies, we compared preadipocyte-loaded hyaluronan or collagen biomaterials and their applicability for adipose tissue engineering. Our findings demonstrated successful de novo formation of adipose tissue in vivo but pore size and stiffness were limiting factors not allowing for sufficient cell distribution in the construct. This study presents a nonwoven made of novel bioabsorbable co-poly(ester amide) based on e-caprolactam, adipic acid, and 1,4-butanediol in an innovative 3-dimensional architecture. The material was formed into nonwovens by textile manufacturing using an aerodynamic web formation process and a needle felting technique. Carriers were seeded with human preadipocytes and examined for cellular proliferation and differentiation. In addition, methods of preparing scaffolds for optimal cell interaction were evaluated. Our findings show that polyesteramide-derived nonwovens allow good adherence, proliferation, and differentiation of preadipocytes. These results are promising guidance toward an optimally designed scaffold for in vivo use.