We aim to determine the level of intraoperative PEEP that optimizes lung compliance without causing a rise in subdural pressure and if we can utilize optic nerve sheath diameter measurement as an indicator for ICP while optimizing lung compliance during supratentorial tumor surgeries.
Application of positive end-expiratory pressure (PEEP) during general anesthesia minimizes ventilation/perfusion mismatch, intraoperative atelectasis and postoperative pulmonary complications. PEEP application in intracranial surgeries is usually avoided due to the risk of raised intracranial pressure (ICP) leading to decreased cerebral perfusion pressure (CPP). Several studies examine the effects of PEEP on subdural pressure and CPP however none examine how lung compliance is affected at the same time. Ultrasound-guided measurement of optic nerve sheath diameter (ONSD) is an indirect indicator of raised ICP and there is limited literature on the correlation of ONSD and ICP during intracranial surgery. In this study, we aim to determine the level of intraoperative PEEP that optimizes lung compliance without causing a rise in subdural pressure and if we can utilize ONSD measurement as an indicator for ICP while optimizing lung compliance during supratentorial tumor surgeries.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
50
Patients will be ventilated with a PEEP of 5 cmH2O during induction of anesthesia. After craniotomy, the PEEP will be reduced to 0 cmH2O for 5 minutes and data will be collected at the end of 5 minutes. Next, PEEP will be increased to 5 cmH2O for 5 minutes and data will be collected at the end of 5 minutes. Finally, PEEP will be increased to 10 cmH2O for 5 minutes and data will be collected at the end of 5 minutes.
Istanbul University - Cerrahpasa, Department of Neurosurgery, Neurosurgical Theaters
Istanbul, Turkey (Türkiye)
RECRUITINGSubdural pressure
22G/ 0.9mm catheter will be introduced into subdural space after craniotomy and connected to the transducer for pressure measurement
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
Optic nerve sheath diameter (left and right)
Ultrasound-guided measurement with the linear probe.
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
Mean arterial pressure
Invasive blood pressure monitoring will be done. The transducer will be kept at the same level as the transducer for the subdural pressure, at the level of the external ear canal
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
Brain relaxation index
1: dura is under the cranium, 2: dura is at the level of the cranium, 3: dura is above the cranium 4: dural pulsations ceased
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
Arterial blood gases
Arterial oxygen pressure and arterial carbon dioxide pressure will be recorded
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
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Regional cerebral oxygen saturation
% - measurement taken with INVOS cerebral oximeter
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)
Lung compliance
L/cmH2O - measurement taken from Draeger Dräger Perseus® A500 mechanical ventilator
Time frame: Measurements will look at the change between 3 timepoints: at 5 minutes with PEEP of 0 cmH2O (T0), then at 5 minutes with PEEP of 5 cmH2O (T5), and finally at 5 minutes with PEEP of 10 cmH2O (T10)