Synergistic Anesthetics Effects of Transcranial Pulsed Current Stimulation for the outpatient extra-corporeal shock wave lithotripsy: a Double blind, Placebo-controlled, Randomized Trial

• Grant number: 18/00234-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2018
• End date: July 31, 2019
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Maria José Carvalho Carmona
• Grantee: Gustavo Rosa Gameiro
• Host Institution: Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

INTRODUCTION: The use of brain stimulation to promote general anesthesia, which was widely used in the first half of the twentieth century, has been completely replaced by drug based anaesthesia. Currently, most anesthetics have short lifecycle and present safe metabolization and elimination. However, in addition to cardiovascular effects, general anesthesia is related to the occurrence of post surgical cognitive dysfunction and possible interference with the development of cases of cancer. Current low intensitiy neurostimulation techniques used in the treatment of chronic pain and depression, among other indications in the study, suggest a possible synergistic effect of transcranial pulsed current stimulation (tPCS) on the level of sedation and analgesia during anesthetic procedures. Extracorporeal shock wave lithotripsy (ESWL) is a painful procedure and requires complete immobility of the patient, thus being preferable general anesthesia to sedate. It has been hypothesized that the use of tPCS can reduce the consumption of remifentanyl and propofol in patients undergoing ESWL. The objective of this study is to evaluate whether there is a synergistic anesthetic effect of the tPCS on the consumption of remifentanyl and propofol in patients undergoing ESWL. METHODS: After approval by the Institutional Ethics Committee and signing of the consenting form, there will be assessed 40 patients between 18 and 60 ASA I-II candidates for ESWL sessions. Participants will be evaluated for cognitive status and will be undergone tPCS and general anesthesia with propofol and remifentanyl. Recruitment of participants for the study occur among those scheduled for ESWL and will be allocated into two groups: tPCS GROUP: 20 minutes before induction of anesthesia there will be held brain stimulation on 2mA intensity and 6-10Hz frequency during 20 minutes using electrodes positioned on earlobes. Control group: this group will receive just 1 minute of tPCS stimulation and 19 minutos of none stimulation before induction of anesthesia. Randomization will be done using the internet site randomizer.com and defined allocations will be stored in opaque envelopes that will be opened after the admission of individuals to the procedure room. There will be "blinding" of the research subjects and the anesthesiologist responsible for the procedure. To perform the tPCS (active or control), the patient will be kept comfortably lying on the operating table as routine procedure to be performed. Besides the usual monitoring for anesthesia, the level of consciousness and anesthetic depth monitor BIS will be used. Qualitative and quantitative EEG will be performed to detect changes in average power by theta, alpha and beta, and coherence values for alpha and theta and four different sub-bands. All monitoring will be maintained up to 1 hour after the end of anesthesia. Anesthesia will be induced and maintained with propofol and remifentanyl infusion and held the anesthesiologist's discretion for maintenance of anesthesia required for ESWL, aiming to maintain BIS between 50 and 60. The airway will be maintained with the use of laryngeal mask introduced immediately after induction. The administration of anesthetic will be suspended at the end of ESWL and awakening from anesthesia will be reviewed until one hour after the procedure. The primary endpoint will be the consumption of propofol and remifentanyl. The secondary analyzed endpoints will be the time and quality of awakening from anesthesia, the heart rate variability, the standard EEG throughout the procedure, the quality of awakening from anesthesia and the cognitive assessment in the seventh day after lithotripsy. The normal distribution of the data will be tested using the Kolmogorov-Smirnov test. Demographic data and the procedure will be compared between groups using the unpaired Student t test. The propofol and fentanyl consumption will be analyzed using the Friedman test followed by the Mann-Whitney test t