In critically ill patients with hypotension, who respond poorly to fluids and vasoactive drugs, cortisol insufficiency may be suspected. In serum over 90% of cortisol is protein-bound, thus routine measures of total serum cortisol may yield 'false lows' due to hypoproteinaemia. Thus, the occurrence of cortisol insufficiency could be overestimated in critically ill patients. Salivary cortisol can be used as a surrogate for free serum cortisol, but in critically ill patients saliva production is decreased, and insufficient volume of saliva for analysis is a common problem. The aim of this study was to investigate if a cotton-tipped applicator with glycerine and citric acid could be used for saliva stimulation without affecting salivary cortisol levels.
Prospective, observational study.
Thirty-six volunteers (six males, 30 females), age 49 ± 9 years, without known oral mucus membrane rupture in the mouth.
Forty-two pairs of saliva samples (22 paired morning samples, 20 paired evening samples) were obtained before and after saliva stimulation with glycerine and citric acid. Salivary cortisol was analysed using Spectria Cortisol RIA (Orion Diagnostica, Finland).