Extremely low bispectral index value during robotic-assisted laparoscopic prostatectomy: A case report

The steep Trendelenburg position and pneumoperitoneum during surgery may affect intracranial pressure and cerebral oxygenation, which in turn may affect the values of the bispectral index (BIS). Prolonged maintenance of the Trendelenburg position and pneumoperitoneum may impair cerebrovascular autoregulation. We present a case of a patient with an extremely low BIS value during robotic-assisted laparoscopic prostatectomy (RALP). We managed the patient under general anesthesia and he showed a prominent decrease in BIS values 6 h after the start of surgery. Suppression ratio (SR) of electroencephalography (EEG) is also decreased, suggesting that the brain activity decreased. The BIS value increased quickly after the Trendelenburg position was released and the anesthesia was terminated. The patient recovered without any neurological deficits and was discharged. Steep Trendelenburg position and pneumoperitoneum can cause EEG abnormalities.