Contributions to nephrology
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Dysnatremias (hypo- and hypernatremia) are common in patients admitted to the intensive care unit (ICU) with a prevalence approaching 20-30% in some studies. Recent data reveals that both hypo- and hypernatremia present on admission to or developing in the ICU are independent risk factors for poor prognosis. The origin of hypernatremia in the ICU is often iatrogenic and due to inadequate free water replacement of ongoing water losses. ⋯ The appropriate use of hypertonic (3%) saline in the treatment of hyponatremic encephalopathy has also shown to be very effective and the use of this therapy is reviewed here. Vasopressin receptor antagonists have also been shown to be effective at increasing serum sodium levels in patients with either euvolemic or hypervolemic hyponatremia and represent another therapeutic option. Recent data demonstrates that proper correction of hyponatremia is associated with improved short- and long-term outcomes.
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Acute kidney injury (AKI) occurring after cardiac surgery is common and extends intensive care unit and hospital length of stay, as well as increases mortality rates. Its causes are multifactorial, and are not limited to ischemia and nephrotoxin administration. ⋯ Certain etiological factors are peculiar to the cardiac surgery setting, such as routine use of cardiopulmonary bypass, and various degrees of hypothermia, which is probably nephroprotective from an ischemia point of view, but which also worsens hemolysis from the pump and thus may actually exacerbate the problem. In this paper we review the place of antifibrinolytic therapy, hemodynamic control on bypass, and the correct level of oxygen delivery in the development of AKI after open heart surgery.
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Septic acute kidney injury (AKI) is the most common form of AKI seen in critically ill patients in developed countries. Its pathogenesis has been traditionally attributed to ischemia secondary to decreased cardiac output and hypotension, which trigger sustained renal vasoconstriction and in turn exacerbate and sustain the ischemia. ⋯ Furthermore, the induction of prolonged severe subtotal ischemia by acute occlusion of the renal artery does not seem to trigger subsequent renal vasoconstriction and, finally, experimental studies suggest that immune-mediated injury may be a more likely cause of tubular cell dysfunction than ischemia. These lines of evidence suggest that the pathogenesis of AKI is complex, does not simply involve ischemia, and may differ according to the etiological trigger.
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Acute kidney injury (AKI) is frequently encountered in the intensive care unit, and from its inception, morbidity and mortality increase in these patients compared to those without AKI. Despite numerous clinical trials and newer pharmacological agents, very little progress has been made to reduce the deaths that occur in this population. ⋯ This critical loss of balance of these mediators appears to be due both to a reduction in clearance and increase in production as demonstrated by experimental studies of bilateral nephrectomy and ischemia-reperfusion, respectively. The evidence and mechanisms for distant organ injury following AKI will be discussed.
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Comparative Study
Continuous ambulatory peritoneal dialysis and automated peritoneal dialysis: are there differences in outcome?
The proportion of peritoneal dialysis (PD) patients on automated peritoneal dialysis (APD) has been steadily increasing over the past decade. In the US, the percentage of PD patients on APD has steadily risen from 9% in 1993 to 54% in 2000. In continuous ambulatory peritoneal dialysis (CAPD), PD exchanges are performed manually, while in APD a mechanical device to assist the delivery and drainage of dialysate is employed. ⋯ APD is also considered to be more suitable form of PD in patients who have a rapid rate of solute transfer across their peritoneal membrane (high transporters) because of the ability to perform rapid frequent exchanges with shorter dwell times. It is not still clear if, with APD when compared to CAPD, a more rapid decline in residual renal function is present. Since the direct costs of APD are over 20% greater than CAPD and given this increasing trend towards greater use of APD, the aim of this paper is to understand if there are really differences in terms of quality of life and outcomes in favor of APD when compared to CAPD.