Clinical Study Of Salivary Cortisol Rhythm And Effects Of Etomidate On Salivary Cortisol Levels In Children Undergoing Urological Surgery

Background: This study aimed to describe the cortisol secretory rhythm and character of healthy children and children undergoing urological surgery, and to investigate the effects of etomidate on cortisol levels, as compared with propofol, in children undergoing urological surgery by using a dynamic assessment tool.Methods: In this prospective, randomized, double-blind, controlled study, 80 children aged 3–12 years with American Society of Anesthesiologists(ASA) physical status I to II who were scheduled for urological surgery and 10 healthy child volunteers were recruited. Before surgery, cortisol levels of the 10 volunteers and 10 patients were tested from wakening, 30 minutes after wakening and 60 minutes after wakening and then cortisol levels of them were tested from 7:00 to 21:00 every hour during a day. Then, the patients were randomly allocated into an etomidate group and a propofol group, receiving etomidate 0.3 mg/kg(n=38) or propofol 2 mg/kg(n=39) and midazolam 0.1mg/kg, fentanyl 2μg/kg, rocuronium 0.6mg/kg for induction, respectively. The cortisol levels of the patients were assessed continuously for two days postoperatively.Results: The cortisol levels of the etomidate group were continuously significantly lower than that of the propofol group from the time of discharging from the post-anesthesia care unit(PACU)(about 14:00) until 8:00 the next morning(F=14.703, P <0.01), and were significantly lower than before surgery at the same time points(F=55.496, P<0.01). No significant differences of cortisol levels were detected between before and after the operation in the propofol group(F=13.176, P>0.01). Also, no significant differences of clinical outcomes were detected between the two groups undergoing surgery(P>0.01). Cortisol of both healthy volunteers and patients had circadian rhythm and cortisol awakening response, there were no significant difference of cortisol level between them.Conclusions: Both of healthy children and patients scheduled for selective minor urological surgery have circadian rhythm and cortisol awakening response. There were no significant difference between healthy children and children scheduled for selective surgery. Compared with propofol, etomidate suppressed cortisol levels in children undergoing urological surgery postoperatively which was short-lived and only last for the first 24 hours without changes of clinical outcomes.