Influence of body position on intracranial pressure during general anesthesia

• Grant number: 21/02982-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): July 01, 2021
• Effective date (End): June 30, 2022
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Maria José Carvalho Carmona
• Grantee: Thiago Silva de Moraes Santos
• Host Institution: Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Influence of body position on intracranial pressure during general anesthesiaOne of the advances in surgery is the laparoscopic surgery, a less invasive technique associated with lower rates of complications and less surgical trauma, as well as quicker recovery and shorter hospitalization period. The technique requires specific positioning in Trendelenburg position (head down position) and pneumoperitoneum (PP) with CO2 . Since the Trendelenburg position consists in a non-physiological positioning, it is associated with temporary changes in cerebral blood-flow and increased intracranial pressure (ICP). The increase in ICP is associated with reduced perfusion and, therefore, cerebral oxygenation. The PP also is associated with increased intracranial pressure, however there are few studies encompassing the association of PP and Trendelenburg position.In 2008, a non-invasive method for measuring IPC was developed by the São Carlos Institute of Physics of the USP. The method patentead by BrainCare, uses a strain gauge mechanical resistance affixed on the surface of the cranium. Many studies demonstrate the safety and applicability of the device. Considering that, for ethical reasons, the ICP cannot be evaluated by invasive method (gold standard), and the current options of measuring carried out by non-invasive methods are totally operator dependent (optical nerve ultrasound, transcranial Doppler imaging, etc.) This study aims to assess the occurrence of intracranial hypertension by non-invasive monitoring of ICP (software BrainCare) in patients undergoing laparoscopic surgeries while in Trendelenburg positioning. This is an observational, prospective study, with the objective of evaluating the accuracy of the non-invasive method of assessing intracranial pressure (BrainCare) in the detection of intracranial hypertension in patients undergoing laparoscopic surgery and/or surgeries that require positioning in the head down position. 48 patients undergoing surgeries will be included in a prospective and consecutive basis, where the positioning is known to be in head down position. Baseline neurocognitive status will be assessed by the Mini-Mental and MOCA test the day before surgery in conjunction with the pre-anesthetic assessment. In the intraoperative period, all patients will be monitored according to the intraoperative routine. Then, with the patient still awake, the non-invasive intracranial pressure fixation tape (NIICP - BrainCare) will be installed. A cerebral oximetry sensor and sensors for assessing anesthetic depth (BIS) will also be installed. After anesthetic induction, ultrasound of the optic nerve sheath will be performed, for serial measurements of intracranial pressure, simultaneously with the other measurements below, except before induction and on awakening. PICNI, cerebral oximetry and BIS measurements will be performed at the following times: * Before and after anesthetic induction * After Trendelenburg positioning and/or insufflation of PP * 10 minutes after Trendelenburg positioning and/or insufflation of PP* 20 minutes after Trendelenburg positioning and/or insufflation of PP * 30 minutes after Trendelenburg positioning and/or insufflation of PP* 1 hour after Trendelenburg positioning and/or insufflation of PP* 2 hours after Trendelenburg positioning and/or insufflation of PPWhen returning to the supine position at the following times: 10 minutes , 20 minutes , 30 minutes and waking up in the operating room. After full recovery from anesthesia (ward), the patient will be reassessed for cognitive status using the Mini-mental and MOCA test. Patients will be followed during hospitalization to assess secondary outcomes of intra-hospital mortality and neurocognitive decline. (AU)