Total Intravenous Anesthesia

his prospective, observational, exploratory, and multicenter study aims to describe the evolution of propofol effect-site concentration administered via target-controlled infusion (TCI) based on the Eleveld model-with adjustments for opioid co-administration-guided by the bispectral index (BIS) during the transition from inhalational anesthesia with sevoflurane to total intravenous anesthesia (TIVA) in pediatric patients.The study population will include 50 pediatric patients, aged 2 to 12 years, scheduled for elective low- or medium-complexity surgeries. Induction will be performed with sevoflurane, followed by intravenous access placement and transition to TIVA using propofol and remifentanil via TCI. As part of the neuromonitoring, the bispectral index, spectral edge frequency (SEF), and median frequency (MF) will be recorded. Additionally, hemodynamic parameters will be recorded on a minute-by-minute basis.The primary objective is to describe BIS-guided adjustments of propofol during the anesthetic transition. Secondary objectives include describing interindividual variability in propofol titration, time to reach a BIS of 40-60, burst suppression patterns, SEF, MF, drug consumption, hemodynamic stability, and clinical adverse events. Statistical analysis will be primarily descriptive, examining correlations between BIS, propofol, and the minimum alveolar concentration (MAC) of sevoflurane.

In this study, the investigators want to examine the effects of intravenous anesthetic drugs and gases on cognitive functions in the postoperative period in individuals who will undergo surgery for obesity. The investigators believe that the anesthesia method we apply with inhalation gases is also as reliable method as total intravenous anesthesia for postoperative cognitive functions in these patients who undergoe sleeve gastrectomy. The anesthesia method applied intravenously and with inahalational gases have been applied safely for many years. Comparisons between these two anesthesia technics in obese individuals and for postoperative cognitive dysfunctions are limited. Studies on the examination of cognitive functions in postoperative patients have gained momentum with the use of neuropsychiatric tests performed on patients who have undergone cardiac surgery and these tests have also been performed on individuals who have undergone non-cardiac surgery. And yet, similar declines in cognitive functions have been observed. For these reasons, the effects of surgery itself and anesthesia methods on cognitive functions have been studied up to date. In this study, the investigators plan to evaluate patients who will undergo obesity surgery in both anesthesia methods by the recovery times from anesthesia and the residual effects of anesthesia, and after awakening they plan to evaluate their cognitive functions with neuropsychiatric tests that will be performed at certain intervals.

This randomized prospective study aims to compare the effects of two target-controlled infusion models, the Schnider and Eleveld models, on anesthetic depth and hemodynamic responses during anesthesia induction in adult patients undergoing spinal surgery. Patients scheduled for spinal surgery will be randomized into either the Schnider or Eleveld group. Before induction, standard monitoring will be applied, including electrocardiography, peripheral oxygen saturation, invasive arterial blood pressure monitoring, heart rate monitoring, and bispectral index monitoring. Anesthesia induction will be performed with fentanyl 2 mcg/kg, rocuronium 0.6 mg/kg, and propofol administered by target-controlled infusion with an effect-site target concentration of 3 mcg/mL according to the allocated pharmacokinetic model. Hemodynamic parameters and bispectral index values will be recorded before induction and at the 1st, 3rd, 5th, and 10th minutes after induction. Additional parameters, including time to BIS below 40, time to delta activity, burst suppression duration, total propofol dose during the first 5 minutes, need for additional propofol, hemodynamic response to intubation, vasopressor requirement within the first 10 minutes, and use of esmolol, will also be documented. The primary aim is to evaluate whether the Schnider and Eleveld models differ in terms of induction-related hemodynamic stability and anesthetic depth during the early induction period.

The purpose of this study is to understand whether certain brain activity patterns that can appear at the beginning of anesthesia are related to how deep anesthesia remains during the operation. The main question of the study is: Do patients who show a pattern called burst suppression during the start of anesthesia experience deeper anesthesia during surgery? Patients who are scheduled for elective surgery under total intravenous anesthesia (TIVA) may take part in this study. During the operation, brain activity will be monitored using a sensor placed on the forehead (Bispectral Index, BIS monitor), which is already commonly used during anesthesia. Information such as BIS values and the doses of anesthesia medications given during the operation will be recorded. Participation in this study will not change the type of anesthesia or the routine care that patients receive during surgery. The study only involves recording and analyzing information collected during standard anesthesia monitoring.

The impact of anesthesia depths on early postoperative neurocognitive complications after total intravenous anesthesia (TIVA) remains controversial. In some studies investigating TIVA, anesthesiologists mainly achieve the target depth of anesthesia by adjusting the dose of propofol, whereas the doses of opioids remains comparable between different anesthetic depth groups, possibly resulting inadequate analgesia. This study is aimed to investigate the impact of different anesthesia depths maintained by target-controlled infusion of propofol and remifentanil at a fixed ratio on the incidence of early postoperative neurocognitive complications in older patients undergoing noncardiac surgery.

This study was planned as a single-center, prospective, randomized trial. Adult patients undergoing elective spinal surgery lasting longer than three hours, performed in a neurosurgery operating room, will be evaluated. Patients managed with three different anesthesia methods currently used will be examined for recovery patterns: 1. Total intravenous anesthesia (TIVA), 2. TIVA Combined anesthesia with sevoflurane and intravenous agents (sevoflurane-CIVIA), 3. TIVA Combined anesthesia with desflurane and intravenous agents (desflurane-CIVIA). Recovery patterns include; extubation time, eye opening time, emergence agitation, postoperative nausia and vomiting and postoperative recovery unit discharge time.

An important feature of neurosurgical anesthesia is early postoperative recovery of consciousness with minimal residual sedation. This is a key factor to enable early neurological assessment and early discovery of postoperative complications. The goal of this single centre clinical trial is to compare propofol/remifentanil anesthesia delivered by manual total intravenous anesthesia (mTIVA) or target controlled infusion (TCI) for intracranial tumor resection via craniotomy. Anesthetic depth will be assessed by a simplified processed EEG (pEEG). The main question is time spent within recommended pEEG- levels from anesthesia induction until end of surgery. Secondary questions are: * mean pEEG-level, time from end of surgery to consiousness, * peroperative propofol/remifentanil consumption * postoperative degree of sleepiness * awareness assessment Participants are adults having have planned surgery for open resection of a brain tumor and will receive general anesthesia with propofol and remifentanil randomized to mTIVA or TCI. pEEG vill be blinded. * Participants will be asked to grade postoperative sleepiness using a specific scale * Follow up regarding awareness will be performed.

Opioids analgesic are the gold standard for intraoperative pain management. Their short- and long-term adverse effect motivate anesthesiologists to explore opioid sparing strategies. Dexmedetomidine is a highly selective α2 adrenergic receptor agonist that could help minimize opioid consumption both intraoperative and postoperative due to its sedative, analgesic and sympatholytic properties. This new randomized controlled trial (RCT) will answer the question whether an intraoperative dexmedetomidine infusion compared to placebo has a clinically significant impact on intraoperative remifentanil consumption during a laparoscopic abdominal elective surgery.