The Effect of Interscalene Block on Intracranial Pressure

Evaluation of the Effect of Interscalene Block on Intracranial Pressure by Sonographic Measurements of Optic Nerve Sheath Diameter and Internal Jugular Vein Collapsibility Index

The study aims to show the effects of interscalene brachial plexus (ISBP) block on intracranial pressure by measuring optic nerve sheath diameter (ONSD) and internal vein collapsibility index (IJV-CI).

40 is the targeted number of patients who are going to have humerus fracture or opened rotator-cuff surgery. Single shot-ISBP block with 25 ml local anesthetic will be performed as anesthetic approach for surgery to all participants. Intraoperative ONSD and IJV-CI measurements will be performed before the ISBP block, 20 minutes and 60 minutes after the block. Hypothesis; external drug-volume effect on internal jugular vein causes decreasing maximum diameter of internal jugular vein (Dmax), venous return from cranium to heart decreases, intracranial pressure can increase.

Inclusion Criteria:

• Patients who had elective humeral fracture and open rotator-cuff surgery,
• Patients aged 18-85 years,
• Patients have ASA I-II anesthesia risk according to the American Society of Anesthesiologists (ASA) risk classification,
• Patients that gave consent for participation in the study will be included.

Exclusion Criteria:

• Patients who do not give consent to the study,
• Patients with infection and open wounds in the area of skin puncture and eyelids,
• Patients have any history of intracranial pathology,
• Patients have nerve blockade contraindications such as coagulation disorder and antithrombotic-anticoagulant use,
• Patients have a history of allergy to one of the study drugs,
• Patients have a body mass index over 35 kg/m2,
• Patients with contralateral pneumothorax,
• Patients with severe respiratory distress,
• Patients with uncontrolled hypertension,
• Patients with acute or chronic eye disease,
• Patients with previous eye surgery,
• Patients using a beta-blocker known to increase intraocular pressure,
• Patients using calcium channel blockers, statins and nitrates,
• Patients in need of intraoperative sedation,
• Patients who develope any complications (hoarseness, horner's syndrome, respiratory distress, local anesthetic toxicity) due to ISBP block will be excluded from the study.