Continuous Renal Replacement Therapy for Burned Patients: Renal and Systemic Considerations

Abstract

SummarySignificant improvements in wound care have re‐sulted in decreased mortality rates in burned pa‐tients since the mid‐seventies. The main determi‐nants of survival remain the extent of the burn and the age. Infection is still the most frequent cause of mortality. Burned patients are prone to develop MOF, not only following sepsis, but from the sys‐temic inflammation associated with thermal injury. Many metabolic derangements occur after a burn:hypermetabolism with several hormonal changes, enhanced catabolism and gluconeogenesis, im‐paired ketogenesis and lipolysis. Aggressive nutri‐tional support is particularly important in burned patients and avoiding a negative nitrogen balance is priority. Since early aggressive fluid resuscitation is widely applied, ARF occurs later during the course hospitalization, often after 10 days. Its pathogen‐esis seems multifactorial, mainly related to sepsis and nephrotoxic agents, and is usually part of MOF. Dialytic support is challenged by the important fluid intake and removal required, the high catabolism, and the hemodynamic instability that characterize burned patients. Since they allow a better hemody‐namic tolerance, a more precise fluid balance, and a more stable metabolic control, CRRTs appear as modalities of choice for ARF burned patients. How‐ever, only three series report their usefulness for this selected population. In our experience, CRRTs have been performed over long periods and have allowed significant fluid loss over time. Bleeding complications from wounds have been much more frequent than for intensive care patients treated by CRRT with a similar anticoagulation regimen, and mandate prudent monitoring. Owing to limited vas‐ cular access sites and inherent risks of arterial cath‐eterization, venovenous might be preferred to arte‐riovenous modalities, if they are available. Despite more aggressive management, the mor‐tality rates of burned patients with ARF remain high80%, reflecting the associated MOF. From a sys‐temic point of view, considering the important vol‐ume loss required, the potential for enhanced cyto‐kine removal, and the important cumulative soluteclearances provided over time by CRRT, ARF burned patients should particularly benefit from continuous over intermittent modalities. When dia‐lytic support has to be initiated, we consider CRRT, particularly hemodiafiltration which provides a larger dialysis dose, as the modality of choice.