DOI: 10.36347/sjmcr.2020.v08i05.011

Pages: 540-542

Severe hypercapnia during surgery is associated with electroencephalographic changes. This report presents a case of a sudden drop in spectral entropy in response to severe hypercapnia during robot-assisted laparoscopic prostatectomy (RALP) in a 75-year-old patient. One hour after pneumoperitoneum and Trendelenburg position application, inadvertent subcutaneous emphysema occurred. Arterial CO2 partial pressure (PaCO2) rose to 85 mmHg, severe respiratory acidosis ensued, and the entropy level dropped to 2. Subsequently, intra-abdominal pressure was reduced by lowering the angle of the Trendelenburg position. Hyperventilation improved respiratory acidosis. Termination of the operation immediately improved acidosis and the entropy level. The sudden drop in spectral entropy may be associated with the narcotic properties of carbon dioxide (CO2).