Effect of PEEP on Subdural Pressure, Optic Nerve Sheath Diameter, Lung Compliance and Brain Perfusion Pressure

Effect of PEEP on Subdural Pressure, Optic Nerve Sheath Diameter, Lung Compliance and Brain Perfusion Pressure

The Effect of Intraoperative Variations in Positive-End Expiratory Pressure on Subdural Pressure, Optic Nerve Sheath Diameter, Lung Compliance and Brain Perfusion Pressure in Supratentorial Tumor Surgery

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.

After craniotomy, PEEP will be adjusted to 0 cmH2O, 5 cmH2O and 10 cmH2O for 5 minutes each to collect the data

Care provider will adjust the PEEP level, make measurements and record arterial blood gas analysis results. Biostatistician will compare data set at each PEEP to each other. Investigator will analyze the data

Patients undergoing elective supratentorial tumor surgery under general anesthesia will be ventilated with positive end-expiratory pressures of 0, 5 and 10 cmH2O after craniotomy.

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.

22G/ 0.9mm catheter will be introduced into subdural space after craniotomy and connected to the transducer for pressure measurement

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)

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)

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

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)

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

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)

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)

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)

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)

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)

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)

Inclusion Criteria: Supratentorial tumor Elective surgery American Society of Anesthesiologist Class I, II or III Exclusion Criteria: Midline shift more than 5 mm determined by intracranial imaging Initial subdural pressure higher than 20 mmHg Requiring intravenous mannitol or hypertonic saline treatment before dural opening Congestive heart failure Pulmonary hypertension Sepsis Hypovolemia Obstructive or restrictive lung disease

Caricato A, Conti G, Della Corte F, Mancino A, Santilli F, Sandroni C, Proietti R, Antonelli M. Effects of PEEP on the intracranial system of patients with head injury and subarachnoid hemorrhage: the role of respiratory system compliance. J Trauma. 2005 Mar;58(3):571-6. doi: 10.1097/01.ta.0000152806.19198.db.

Mascia L, Grasso S, Fiore T, Bruno F, Berardino M, Ducati A. Cerebro-pulmonary interactions during the application of low levels of positive end-expiratory pressure. Intensive Care Med. 2005 Mar;31(3):373-9. doi: 10.1007/s00134-004-2491-2. Epub 2005 Jan 25.

Flexman AM, Gooderham PA, Griesdale DE, Argue R, Toyota B. Effects of an alveolar recruitment maneuver on subdural pressure, brain swelling, and mean arterial pressure in patients undergoing supratentorial tumour resection: a randomized crossover study. Can J Anaesth. 2017 Jun;64(6):626-633. doi: 10.1007/s12630-017-0863-7. Epub 2017 Mar 24.

Corradi F, Robba C, Tavazzi G, Via G. Combined lung and brain ultrasonography for an individualized "brain-protective ventilation strategy" in neurocritical care patients with challenging ventilation needs. Crit Ultrasound J. 2018 Sep 17;10(1):24. doi: 10.1186/s13089-018-0105-4.

Rasmussen M, Bundgaard H, Cold GE. Craniotomy for supratentorial brain tumors: risk factors for brain swelling after opening the dura mater. J Neurosurg. 2004 Oct;101(4):621-6. doi: 10.3171/jns.2004.101.4.0621.

Ruggieri F, Beretta L, Corno L, Testa V, Martino EA, Gemma M. Feasibility of Protective Ventilation During Elective Supratentorial Neurosurgery: A Randomized, Crossover, Clinical Trial. J Neurosurg Anesthesiol. 2018 Jul;30(3):246-250. doi: 10.1097/ANA.0000000000000442.