During cardiopulmonary bypass (CPB) in open-heart surgery, direct measurement of intracranial pressure is not feasible. Evaluation of the optic nerve sheath diameter (ONSD) by ultrasonography is considered a reliable method for predicting increases in intracranial pressure. This study aims to investigate changes in ONSD in patients undergoing open-heart surgery with CPB.
Several mechanisms during CPB-including inflammatory response, hemodilution, reperfusion injury, hypothermia-rewarming imbalances, and microembolism formation-can lead to increased intracranial pressure and cerebral edema. Ultrasonographic measurement of ONSD provides a noninvasive means of monitoring these changes. In this study, ONSD will be measured at different time points, while hemodynamic parameters, NIRS values, and arterial blood gas analyses will be recorded simultaneously. The primary objective is to evaluate changes in ONSD, and the secondary objective is to determine the potential impact of these changes on intracranial pressure.
Study Type
OBSERVATIONAL
Enrollment
40
Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) will be performed using a 7.5 MHz linear probe. Measurements will be taken 3 mm behind the globe in both transverse and sagittal planes, three times for each eye, and the average value will be recorded at predefined time points during cardiopulmonary bypass.
Medipol University
Istanbul, Turkey (Türkiye)
Change in Optic Nerve Sheath Diameter (ONSD)
Evaluation of ONSD changes measured by ultrasonography to assess potential alterations in intracranial pressure during cardiopulmonary bypass.
Time frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Mean Arterial Pressure (MAP)
Measurement of mean arterial pressure.
Time frame: From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Central Venous Pressure (CVP)
Measurement of central venous pressure.
Time frame: From induction of anesthesia until the end of surgery, recorded simultaneously with OSD measurements.
Arterial Blood pH
Analysis of arterial blood pH values
Time frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Partial Pressure of Arterial Carbon Dioxide (PaCO₂)
Analysis of partial pressure of arterial carbon dioxide.
Time frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
Lactate
Analysis of blood lactate levels.
Time frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).
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partial Pressure of Arterial Oxygen (PaO₂)
Analysis of partial pressure of arterial oxygen.
Time frame: From tracheal intubation (baseline) until the end of surgery (approximately 4-6 hours); measurements at six predefined time points (post-intubation, CPB initiation, 15 min, 45 min, 15 min after CPB termination, end of surgery).