Pathogenesis and management of septic shock

Prevention of perioperative acute renal failure: what works?

Perioperative acute renal failure (ARF) is associated with increased morbidity and mortality. Patients undergoing cardiac, vascular and major abdominal surgery and those with pre-operative renal insufficiency are at increased risk for developing post-operative ARF. The aetiologies of perioperative ARF are multi-factorial. However, pre-renal azotaemia and ischaemic acute tubular necrosis (ATN) are the predominant causes. Preventive strategies involve identifying patients at risk, optimizing intravascular volume as well as renal function with perioperative haemodynamic monitoring, and avoiding nephrotoxins. Various pharmacological agents have been used to optimize renal perfusion and tubular function. Unfortunately, none has been shown to be effective in randomized placebo-controlled trials. In this chapter, we discuss the prophylactic use of fluids, vasoactive drugs, diuretics and other agents, as well as modification of surgical techniques to reduce the incidence of perioperative ARF.

Approach to intradialytic hypotension in intensive care unit patients with acute renal failure

The increasing prevalence of acute renal failure (ARF) patients with hemodynamic intolerance of intermittent hemodialysis (HD), generally because of septic vasoparesis or severe cardiac dysfunction, has led to the development of several strategies to improve the delivery of renal replacement therapy (RRT) in ARF patients. Intradialytic hypotension (IDH) is caused by the interaction of dialysis-dependent and dialysis-independent factors. Dialysis-dependent factors include the prescriptions for fluid removal, solute removal, and dialysate components such as sodium, buffer, and calcium. Dialysis-independent factors include hemodynamic compromise caused by hypovolemic, cardiogenic, vasodilatory, and mixed mechanisms. We propose an approach to the prevention and management of IDH in critically ill ARF patients, which minimizes hypovolemic, cardiogenic, and vasodilatory insults by optimizing fluid removal, cardiac function, and vascular contractility.