Objectives: To investigate the contribution of Bispectralindex monitoring on the amount of used anaesthetic substance and the quality of anaesthesia in patients with persistent atrial fibrillation who would undergo cardioversion. 

Methods: The prospective, randomised, controlled clinical study was conducted at Akdeniz University, Antalya, Turkey from October 2010 to November 2011 Sedation was performed on 50 adult patients using midazolam and fentanyl. Patients were randomised to group 1 and 2. In group 1 cardioversion was performed when the BispectralIndex value was seen to have decreased to <80 and the Ramsay sedation score was 5-6. In Group 2, BispectralIndex monitor was blinded to the investigator, and cardioversion was performed when Ramsay sedation score was 5-6. In both groups, blood pressure, heart rate and Bispectral index values were recorded. Total anaesthetic amount, awareness and pain were also assessed. SPSS 13 was used for statistical analysis. 

Results: Overall, 23(46%) patients were male and 27(54%) were female and there was no significant difference in the two groups in terms of age (p>0.05). No statistically significant difference was detected between the groups in terms ofinduction time, anaesthetic need and Bispectral Index values (p>0.05). In both groups, 2(8%) patients perceived pain and 2(8%) perceived the procedure. 

Conclusion: In the presence of anaesthetist in the team, Bispectral Index monitoring did not contribute to the determining of anaesthetic drug dosage and the depth and quality of anaesthesia in patients with persistent atrial fibrillation during cardioversion.