Comparison of the Effects of Deep and Moderate Neuromuscular Blockade on Optic Nerve Sheath Diameter

Increased intracranial pressure (IICP) is a common problem in traumatic brain injuries and many medical diseases. Early recognition of IICP can save lives. Several invasive and non-invasive methods have been described for IICP diagnosis. In recent years, ultrasonographic measurement of optic nerve sheath diameter (ONSD) has become a popular method due to its high sensitivity and specificity for IICP estimation. Studies have shown that ONSD's ultrasonographic measurement correlates with the IICP and can detect intracranial hypertension. The ONSD measurement has advantages such as being easily applied by the clinician at the bedside, being non-invasive, providing immediate results, reproducibility and low cost. It is known that artificial carbon dioxide pneumoperitoneum created in laparoscopic surgeries increases intracranial pressure.However, it is not easy to estimate the degree of changes in ICP during laparoscopic surgery under general anesthesia. In the literature, there are many studies on the sonographic measurement of optic nerve sheath diameter to evaluate the effects of trendelenburg position on intracranial pressure with the use of different anesthetic drugs in laparoscopic surgeries. In addition, there are studies reporting that deep neuromuscular blockade in laparoscopic surgeries increases surgical vision and decreases analgesic requirement in postoperative period. The relationship between neuromuscular block level and intracranial pressure is not clear. From this point of view, the investigators would like to evaluate the effect of moderate and deep neuromuscular block level on intracranial pressure by sonographic measurement of optic nerve sheath diameter in laparoscopic cholecystectomy operations performed with standard pressure artificial carbon dioxide pneumoperitoneum.