Administration of C1 inhibitor reduces neutrophil activation in patients with sepsis

Management of severe sepsis and septic shock

PURPOSE OF REVIEW

Severe sepsis and septic shock are common and deadly conditions for which the epidemiology, pathogenesis, and management continue to evolve. Recent publications (2003 and early 2004) have been systematically reviewed for important new original research and scholarly reviews, with an emphasis on clinical advances in adults.

RECENT FINDINGS

Important new epidemiologic studies establish the increasing frequency (nearly 9% per year) and falling mortality rates associated with sepsis. Sepsis definitions were reviewed by a group of experts, and the principal features of the 1991 consensus conference definitions were supported, with a new framework for evaluation of sepsis proposed. New research and thoughtful reviews continue to elucidate the pathogenesis of sepsis, with emphasis on innate immunity and time-based changes in immune status, varying from hyperreactive immunity and inflammation to immune depression with enhanced risk for nosocomial infections. A comprehensive evidence-based approach to the management of severe sepsis is presented in an important document developed by representatives from many critical care and infectious disease societies. Management includes early targeted resuscitation, broad empiric antibiotic coverage and source control, effective shock evaluation and treatment, adjuvant therapy with recombinant human activated protein C and moderate-dose hydrocortisone in selected patients, and comprehensive supportive care. Recently published multicenter clinical trials for novel agents have been disappointing, particularly for a nitric oxide synthase inhibitor that effectively supported blood pressure but increased mortality.

SUMMARY

The works reviewed reflect the advances in the care of patients with sepsis.

Complement membrane attack complex and hemodynamic changes during human orthotopic liver transplantation

Hemodynamic changes and elevation of intracellular calcium following reperfusion in human liver transplantation occur rapidly and do not match the time course of cytokine expression, therefore, we postulate involvement of other, pre-formed substances, such as complement. We studied 40 adult patients undergoing liver transplantation. Blood was drawn for estimation of C3, C4, C3 degradation product, membrane attack complex, and CH100 levels and elastase (a marker of neutrophil activation) at induction of anesthesia, 5 minutes before reperfusion, 5 minutes and 60 minutes after reperfusion. Cardiac output was measured by thermodilution and systemic vascular resistance was calculated at these same time points. There was a significant rise in C5b-9 membrane attack complex (P =.0012) with a corresponding fall in C3 (P =.0013) and C4 (P =.0002) levels and a rise in C3 degradation product levels (P =.0006). There was no significant change in CH100. These changes very closely followed the hemodynamic changes of a significant fall in systemic vascular resistance index (P =.0024) and increase in cardiac index (P =.0005). Elastase rose from 356 +/- 53 to 557 +/- 40 microg/L (P <.0001). There is complement activation and neutrophil activation at reperfusion in liver transplantation. Dilution alone cannot explain the fall in C3 and C4 levels as there is a corresponding increase in membrane attack complex and C3 degradation product levels with time. As both C3 and C4 are consumed, the classical pathway must be active, though alternative and lectin activated pathways may also be involved. These findings may, at least in part, explain the hemodynamic changes typically seen at reperfusion in liver transplantation.