Determination of salivary cortisol to assess time-related changes of the adrenal response to stress in critically ill patients

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 (TO) and after 48 h (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 stress-induced response and appears as a suitable tool for multiple measurements over time.