Extracorporeal Circulation and Optic Nerve Ultrasound: A Pilot Study

Area of Science:

• Neurosurgery
• Cardiothoracic Surgery
• Anesthesiology

Background:

• Cardiopulmonary bypass (CPB) is essential for cardiothoracic surgery but can disrupt the blood-brain barrier, potentially altering intracranial pressure (ICP).
• Monitoring ICP non-invasively is crucial for managing patients undergoing CPB.
• Optical nerve sheath diameter (ONSD) measurement offers a promising non-invasive approach for ICP assessment.

Purpose of the Study:

• To evaluate the efficacy of ultrasound-guided ONSD measurements for monitoring ICP changes during extracorporeal circulation.
• To assess the feasibility of ONSD as a real-time, non-invasive ICP monitoring tool in patients undergoing CPB.

Main Methods:

• Twenty-one adult patients undergoing extracorporeal circulation were enrolled.
• Optic nerve sheath diameter (ONSD) was measured using ultrasonography at baseline and at 30, 60, and 90 minutes during CPB.
• Non-invasive ICP (nICP) values were calculated from ONSD measurements.

Main Results:

• Baseline mean ONSD values were 4.13 mm (right eye) and 4.36 mm (left eye).
• Calculated baseline nICP values were 11.0 mm Hg (right eye) and 10.89 mm Hg (left eye).
• A statistically significant increase in ONSD and calculated nICP was observed during CPB compared to baseline (p < 0.005).

Conclusions:

• Ultrasound-guided ONSD measurement is a practical, cost-effective, and low-risk method for bedside ICP monitoring during CPB.
• This technique allows for continuous assessment of ICP dynamics throughout extracorporeal circulation.
• ONSD monitoring can aid in timely interventions and improved patient outcomes in cardiothoracic surgery.