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BACKGROUND: The value of salivary cortisol measurement to study stress-related adrenal response is controversial. The study aim was to assess the role of salivary cortisol measurement to detect time-related changes of adrenal response in critically ill patients. PATIENTS AND METHODS: Patients with organ failure, sepsis or trauma were prospectively recruited in the Emergency Department. Serum and salivary cortisol were measured at baseline (T0) and after 48 hours (T48). In 33 patients ACTH test was also done. RESULTS: Fifty-five patients were studied and classified as septic (22) or non-septic (33). We found a significant correlation between serum and salivary cortisol at T0 and T48. No patient had baseline serum cortisol < 276 nmol/L and salivary cortisol significantly decreased at T48 in almost all patients. A delta serum cortisol < 250 nmol/L after ACTH was found in only 4 patients who showed elevated baseline cortisol levels. CONCLUSION: We found that reduced baseline and post-ACTH cortisol levels are uncommon in our samples. In patients able to provide adequate saliva samples, salivary cortisol may be used to check the degree of stressinduced response and appears as a suitable tool for multiple measurements over time.

Background: Most clinical trials of sepsis treatment modalities fail at their primary objective of establishing superiority over placebo when added to background standard of care. While there is no definitive explanation for the high failure rate, it might be stated that our attempts to insert a new therapeutic agent into standard of care encounters severe problems with definition of exactly what stage is ongoing, and what are the criteria for progression or resolution from that time point onwards. Clearly there is need for a means of defining steps in the septic process that would apply to individuals, and to better define the course of sepsis in each patient after they are enrolled in a trial. Methods: For core model development, 30 septic patients were studied for time-related progression in relation to biomarkers, employing a Load Model in a neural net algorithm in MatLab. Causative bacterial infections were linked to primary infection sites. In order to minimize overparameterization, the model was allowed to estimate outputs using the best three input parameters. Bacterial load was tracked from origin using clinical and microbiologic data to provide an estimate at the start of sepsis. The bacterial load as well as clinical and laboratory parameters were model inputs with the output parameter being organ failures and/ or mortality. Results: At onset of sepsis, human bacterial load estimates ranged from between 10 8 and 10 11 CFU, which is consistent with inocula in animal models of sepsis. Sepsis proceeds to organ failures and mortality in a series of steps that are initially linked to bacterial load and inflammatory response, followed by coagulopathy, ischemia, oxygen deprivation in organs and tissues, and culminating in organ failures. The later stages of sepsis are all driven by metabolic parameters, and there seems to be little benefit to blocking inflammation at later stages. Substrate and oxygen deficiencies must be addressed first. Conclusion: Neural net progression models based on biomarkers and physiological markers are able to describe the evolution of sepsis to septic shock, organ failures, and provide some evidence that mortality may be a consequence of the stages of sepsis. Overall, these models appear useful to the task of sorting out organ failure endpoints and mechanisms in individual patients with sepsis progression across sepsis to septic shock. P2 Extracellular matrix turnover, angiogenesis and endothelial function in acute lung injury: relationship to pulmonary dysfunction and outcome