Correlation Salivary Cortisol and Free Serum Cortisol to Total Serum Cortisol in MICU Septic Shock

The purpose of the study is: * to correlate salivary cortisol to free serum cortisol (as salivary cortisol is considered to be almost complete free cortisol) and, * to correlate free serum cortisol to total serum cortisol levels Both in patients with septic shock (severe sepsis requiring vasopressors). We believe that: * total serum cortisol does not correlate with free serum cortisol in patient with septic shock and, * that salivary cortisol correlates with free serum cortisol and can be used to determine the level of free serum cortisol.