Comparing EEG Patterns in Different Age Groups During General Anesthesia With Sevoflurane
Condition: Anesthesia
Study type: Observational

Summary: 
      This study is being conducted to evaluate and assess the electroencephalography wave patterns
      in different age patients undergoing surgery under general anesthesia. The aim of our study
      is to compare the raw EEG waves in different age patients and analyze any changes in these
      patterns among various age groups and which of these groups will have the EEG signal of
      high-frequency waves or low frequency waves. Previous studies have shown that light sedation
      is often accompanied by decreasing posterior alpha waves and increasing the intensity of
      frontal/central beta waves. It is therefore of neuroscientific interest to assess whether the
      electroencephalographic correlates of sevoflurane-induced unconsciousness have different or
      similar frequency range among the age groups.
    

Detailed description: 
      EEG is a powerful tool that refers to the recording of the brain's spontaneous electrical
      activity along the scalp and it can be used to measure voltage fluctuations which result from
      ionic current flows within neurons found in the brain.The electroencephalogram is
      increasingly used to measure anesthetic drug effect on the central nervous system.The use of
      electroencephalographic monitors has been proven to decrease drug consumption during
      anesthesia and to lead to a faster recovery from anesthesia. Recently, the use of the
      Bispectral Index® (BIS®) monitor (Aspect Medical Systems, Newton, MA) has been shown to
      decrease the incidence of intraoperative awareness. Depth of anesthesia is frequently
      assessed using electroencephalogram processing systems, such as BIS and M-Entropy®
      (Datex-Ohmeda, Helsinki, Finland). The use of these monitors has been claimed to allow more
      accurate drug administration which has the theoretical benefit of avoiding phases of too
      light or too profound anesthesia and the associated risks of hemodynamic instability.
      Inadequate general anesthesia caused by under dosage causes intraoperative awareness whereas
      prolonged anesthesia increases the risk of postoperative complications because of over
      dosage. The most important factor that contributes to the inadequate general anesthesia is
      the current limited ability to determine the level of awareness. In this study, the
      investigators want to analyze the raw EEG waves under general anesthesia using sevoflurane of
      MAC 1.0 for different age groups from 0 to 80 years old. The relation between concentration
      of 1.0 MAC sevoflurane and raw EEG states in different age groups is relatively unstudied. In
      this prospective randomized study the investigators want to know if there is any correlation
      of brain waves under general anesthesia in different age groups. Given that the brain rapidly
      develops and undergoes significant changes from childbirth into adulthood, anesthesia induced
      EEG oscillations in children might differ from those of adults, and could vary significantly
      with age. Characterizing the structure of the EEG in relation to age would help establish the
      foundations for age-appropriate monitoring of brain states during general anesthesia and
      sedation in children. The investigators aimed to examine the effects of age on the EEG during
      general anesthesia, with sevoflurane as the sole hypnotic agent.

      After arrival in the operating room, an intravenous line will be inserted into a large
      forearm vein, and standard monitors will be applied. Each patient will be continuously
      monitored by a 3-lead electrocardiogram, noninvasive arterial pressure, pulse oximetry, and
      end-tidal carbon dioxide concentration.

      The induction of anesthesia will be the same in all age groups and will consist of sufentanil
      0.2-0.3mcg/kg or fentanyl 1-2 mcg/kg before intubation and 0.2 mg/kg cisatracurium to
      facilitate intubation. Sevoflurane inhalation will be adjusted in all age groups to maintain
      1.0 MAC concentration. After tracheal intubation, patients will be ventilated with a tidal
      volume of 6-8 ml/kg and the respiratory rate will be adapted to obtain an end-tidal carbon
      dioxide concentration of 30-35 mmHg.
    

Intervention name(s): Sevoflurane Inhal Soln
Intervention type(s): Drug
Intervention description(s): Anesthesia will be induced by sevoflurane inhalation only with a tight-fitting facemask and a 4-l airflow of 100% oxygen. Sevoflurane inhalation will be adjusted in all age groups to maintain 1.0 MAC concentration
Intervention MeSH terms: Sevoflurane
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        120 patients undergoing minor elective surgeries will be allocated in 6 age groups: 0-1
        year old (infant period), 1-3 years old (toddler period), 3-6 years old (preschool age
        period), 7-18 years old (school age period), 18-65 years old (adults) and 65-80 years old
        (elderly).
      
Keywords: electroencephalography; general anesthesia; sevoflurane