1. 1. September 2016 • Volume 123 • Number 3 Supplement PR215 VARIABILITY OF ENTROPY AS AN INDICATOR FOR STABILITY OF ANAESTHESIA DEPTH DURING IN VITRO FERTILIZATION PROCEDURES V. Potievskaya1,* , I. Ushakov2 1 Anaesthesiology and Intensive Care, Russian Medical Academy for Postgraduate Training, 2 Anaesthesiology, Clinical hospital Moskvorechye, Moscow, Russian Federation Background & Objectives: It has been shown that entropy monitoring allows to assess depth of anaesthesia and improves anaesthesia awareness [1, 2]. Usually response entropy (RE) and state entropy (SE) are measured. We suggested a new calculated parameter - variability of entropy (VE) to evaluate stability of anaesthesia. The objective of the study was to compare stability of intravenous propofol and volatile sevoflurane anaesthesia during oocytes retrieval by VE assessment. Materials & Methods: 26 women of ASA physical status I scheduled for oocytes retrieval were randomized into two groups. Induction of anaesthesia was performed with sevoflurane (group 1) or intravenous intermittent propofol boluses (group 2). RE and SE were recorded, VE was calculated as RE-SE/SE×100%. We compared results in the two groups during periods of induction, time of oocyte retrieval (intervention) and awake. Data were presented as median [25%; 75% interquartile ranges], Mann-Whitney test was applied. Results: In all patients RE and SE values decreased during all periods that reflected adequate depth of anaesthesia and did not significantly differ between groups. VE was higher in the group of propofol comparing with sevoflurane during periods of oocyte retrieval (p<0.05), but there was no significant difference in the period of induction and awakening period between two groups (table). This fact may reflect analgesics effect of sevoflurane because of lower RE values. Table.Variability of entropy during sevoflurane and propofol anaesthesia. Variables Sevoflurane Propofol P VE baseline, % 10,1[10; 12,9] 10,1 [8,8; 11,4] 0,89 VE induction, % 5,2 [1,2; 21,4] 39,1 [6,2; 26,4] 0,34 VE intervention, % 0 [0; 4,8] 16,6 [0; 20] 0,02 VE awake, % 10,5 [8,7; 15,1] 10,5 [9,2; 12,6] 0,98 Conclusion: Assessment of variability of entropy in addition to RE and SE allows not only detect the depth of anaesthesia, but also more clearly evaluate its stability and balance of hypnotic and analgesic effects. Use of volatile anaesthetic sevoflurane during oocytes retrieval demonstrated more stable anaesthesia level than propofol. References: 1. Bein B. “Entropy”. Best practice&research clinical anesthesiology 2006, 20 (1): 101-109. 2. Gao JD, Zhao YJ, Xu CS, Zhao J et al. “Evaluation of entropy for monitoring the depth of anesthesia compared with bispectral index: a multicenter clinical trial”. Chin Med J (Engl), 2012, 125 (8): 1389–92. Disclosure of Interest: None declared DOI: 10.1213/01.ane.0000492613.99776.0c