Optic nerve sheath diameter-guided extubation plan in obese patients undergoing robotic pelvic surgery in steep Trendelenburg position: A report of three cases.

Robotic pelvic surgery requires steep Trendelenburg positioning with pneumoperitoneum which causes raised thoracic and intracranial pressures. In obese patients, the basal thoracic pressures are high. Increased intrathoracic pressure can decrease the cranial venous flow leading to deficient intracranial absorption of cerebrospinal fluid and a further increase in intracranial pressure. Operating times are also longer due to unfavorable anatomy. Such patients frequently have a delayed awakening from anaesthesia due to a combination of factors such as hypercapnoea, acidosis, and raised intracranial pressures. Normocapnoea can be achieved in a ventilated patient towards the end of surgery. In cases where the anaesthetic agents have been washed out and normocapnoea has been achieved, the intracranial pressure may be an important factor causing delayed emergence. The sonographically measured optic nerve sheath diameter correlates with the intracranial pressure. We report three cases of robot-assisted pelvic surgery in obese patients where we used the optic nerve sheath diameter as a guide for the timing of extubation.