"Sepsis"--clarity of existing terminology ... or more confusion?

Sepsis and septic shock: selection of empiric antimicrobial therapy

This article is a brief overview of empiric antibiotic selection for sepsis and septic shock. The article includes a differential diagnosis of the mimics of sepsis and stresses a strategy for avoiding problems associated with antibiotic resistance. Although early appropriate empiric therapy is the cornerstone of sepsis and septic shock therapy, nonantibiotic interventions are critical as well. In patients with septic shock, adequate and effective early volume replacement is essential. Early surgical intervention is critical in controlling and eliminating the septic focus if sepsis is related to perforation of a viscus (eg, the colon); obstruction of the biliary, gastrointestinal, or urinary tract; or presence of an abscess that requires drainage. If device-related infection is the cause of sepsis, device removal is essential. Empiric monotherapy for sepsis and septic shock is preferred. Multiple-drug therapy is more expensive, has an increased potential for drug-drug interactions, has a higher likelihood of side effects, and does not decrease the resistance potential of the antibiotics being used. For these reasons, early empiric monotherapy is optimal and de-escalation is not necessary if initial mono therapy was wisely selected.

Measures, markers, and mediators: toward a staging system for clinical sepsis. A report of the Fifth Toronto Sepsis Roundtable, Toronto, Ontario, Canada, October 25-26, 2000

BACKGROUND

Sepsis is not a single disease but a complex and heterogeneous process. Its expression is variable, and its severity is influenced by the nature of the infection, the genetic background of the patient, the time to clinical intervention, the supportive care provided by the clinician, and a number of factors as yet unknown. The evaluation of effective therapies has been hampered by limitations in our ability to characterize the process and to stratify patients into more homogeneous groups with respect to pathogenesis.

OBJECTIVES

To develop a taxonomy of markers relevant to clinical research in sepsis and to propose a testable candidate system for stratifying patients into more therapeutically homogeneous groups.

DATA SOURCE

An expert roundtable discussion and a MEDLINE review using search terms "marker" and "sepsis."

RESULTS

Markers provide information in one or more of three domains: diagnosis, prognosis, and response to therapy. More than 80 putative markers of sepsis have been described. All correlate with the risk of mortality (prognosis), yet none has shown utility in stratifying patients with respect to therapy (diagnosis) or in titrating that therapy (response). Their limitations arise from the challenges of establishing causality in a complex disease process such as sepsis and of stratifying patients into more homogeneous populations. The former limitation may be addressed through a modification of Koch's postulates to differentiate causality from simple association. The latter suggests the need for a staging system analogous to those used in other complex disease processes such as cancer. A candidate framework for such a system, based on the infection, the host response, and the extent of organ dysfunction (the IRO system) is described.

CONCLUSIONS

Advances in the understanding and management of patients with sepsis will necessitate more rigorous approaches to disease description and stratification. Models should be developed, tested, and modified through clinical studies rather than through consensus.

Subcellular membrane impairment and application of phospholipase A2 inhibitors in endotoxic shock

The study aims at elucidating the mechanism involved in the cell dysfunction or impairment and the protective effects of phospholipase A2 (PLA2) inhibitors in endotoxin shock. Thirty-four rabbits were divided randomly into four groups: (1) normal control group (NC, n = 6), receiving saline intravenously; (2) endotoxin shock group (ES, n = 12), receiving 3 mg/kg of E. coli endotoxin; (3) chloroquine pretreated group (CQ, n = 8), receiving 3 mg/kg of chloroquine 3 min before endotoxin injection and (4) chlorpromazine pretreated group (CPZ, n = 8), receiving 0.3 mg/kg of chlorpromazine 30 min before endotoxin injection. Hepatic mitochondria were extracted either 8 h after commencement of the experiment or when the animals died for detecting PLA2 activity, membrane fluidity, membrane bound succinate dehydrogenate (SDH) and malondialdehyde (MDA). Mitochondria of the lung, heart and kidney were also used for detection of the membrane fluidity. It was revealed that the survival rate of 8 h was 100% (NC), 58% (ES), 87.5% (CQ) and 75% (CPZ), respectively. Mean arterial pressure (MAP) dropped soon after endotoxin injection and descended continuously afterwards in the ES group (P < 0.01). Fluorescence polarization, microviscosity and anisotrophy with a DPH probe were elevated above control levels (P < 0.01). SDH was decreased obviously following endotoxin infusion (P < 0.01). Chloroquine and chlorpromazine, serving as PLA2 inhibitors, could abate cellular dysfunction and increase survival rate. It is proposed that PLA2 plays a pivotal role in cellular injury in endotoxin shock. PLA2 inhibitor might serve as a useful adjunct in combating sepsis and shock.

"Sepsis/SIRS," physiologic classification, severity stratification, relation to cytokine elaboration and outcome prediction in posttrauma critical illness

OBJECTIVE

To develop a quantitative severity stratification within the framework of a Physiologic State Classification (PSSC) system that can be applied to critically ill post-trauma patients with "sepsis/SIRS" and to relate PSSC to the nature of the plasma cytokine response.

MATERIALS AND METHODS

At each study time period, a patient was classified into one of seven physiologic States previously derived from clustering 17 cardiopulmonary and metabolic variables from 338 critically ill patients: R = reference, A = normal stress response, B = metabolic insufficiency, C1 (early) and C2 (late) = respiratory insufficiency, D = cardiogenic insufficiency, H = nonshock hypovolemia.

MAIN RESULTS

The PSSC used State data from a developmental set of 159 trauma patients in a logistic model (L2PDEATH) to provide a quantitative index of severity. This severity index was tested on 80 new trauma patients (mean injury Severity Score (ISS) = 27.6, 64% survivors). Using PSSC State distributions for evaluation of enzyme-linked immunosorbent assay (ELISA) measured cytokines interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF) showed the multicytokine score to be greatest in those C2- and B-State regions associated with a higher severity as measured by L2PDEATH. Compared with ARDEATH of the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system, L2PDEATH provided a better indicator of severity of sepsis/systemic inflammatory response syndrome (SIRS) for posttrauma patients.

CONCLUSIONS

PSSC allows classification of the physiologic and cytokine mediator response to trauma and permits stratification of severity in posttrauma critical illness.

Multiple organ failure. Pathophysiology and potential future therapy

Multiple organ failure (MOF) has reached epidemic proportions in most intensive care units and is fast becoming the most common cause of death in the surgical intensive care unit. Furthermore, in spite of the development of successive generations of new and more powerful antibiotics and increasing sophisticated techniques of organ support, our ability to salvage patients once MOF has become established has not appreciably improved over the last two decades. Clearly, new therapeutic strategies aimed at preventing or limiting the development of the physiologic abnormalities that induce organ failure are needed to improve survival in these critically ill patients. Based on our rapidly increasing knowledge of the mechanisms of MOF and the fruits of molecular biology, a number of new therapeutic approaches are in various stages of development. To effectively use these new therapeutic options as they become available, it is necessary to have a clear understanding of the pathophysiology of MOF. Thus, the goals of this review are to integrate the vast amount of new information on the basic biology of MOF and to focus special attention on the potential therapeutic consequences of these recent advances in our understanding of this complex and perplexing syndrome.

Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine

An American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference was held in Northbrook in August 1991 with the goal of agreeing on a set of definitions that could be applied to patients with sepsis and its sequelae. New definitions were offered for some terms, while others were discarded. Broad definitions of sepsis and the systemic inflammatory response syndrome were proposed, along with detailed physiologic parameters by which a patient may be categorized. Definitions for severe sepsis, septic shock, hypotension, and multiple organ dysfunction syndrome were also offered. The use of severity scoring methods when dealing with septic patients was recommended as an adjunctive tool to assess mortality. Appropriate methods and applications for the use and testing of new therapies were recommended. The use of these terms and techniques should assist clinicians and researchers who deal with sepsis and its sequelae.

Problems in assessing the technology of critical care medicine

Technology assessment is becoming increasingly important in the area of critical care due both to the explosion of technology associated with this discipline and to the realization that future demand for these health care resources will undoubtedly exceed the ability to pay. Technology assessment remains both confusing and controversial to many physicians. This review tries to address some of the confusion by reviewing the basic strategies involved in this process. From there, problems and prospects for the evaluation of critical care as a program are presented, followed by the assessment of components within the area of critical care. Finally, recommendations are made on how technology assessment could proceed in the future to best achieve the efficient provision of this service.