Influence of Monitoring the Depth of General Anesthesia Upon the Incidence of PONV and Emergence Delirium in Children Undergoing Endoscopic Adenoidectomy in General Anesthesia
Condition: Postoperative Nausea; Postoperative Vomiting; Emergence Delirium
MeSH terms: Delirium; Emergence Delirium; Nausea; Vomiting; Postoperative Nausea and Vomiting
Study type: Interventional

Summary: 
      The study has been designed as a prospective randomized clinical trial. Due to the use of a
      bispectral (BIS) monitor in the interventional arm, the study will not be blinded for the
      anesthetist. The total planned number of study subjects is 100. Patients will be randomly
      randomized upon arrival to the operating theatre (using the envelope method) into the
      interventional arm (BIS monitoring of the depth of general anesthesia), and into the control
      group (standard management of general anesthesia to minimum alveolar concentration (MAC)
      1,0). The target values of the depth of general anesthesia according to BIS are between 40
      and 60.
    

Detailed description: 
      The condition of postoperative nausea and vomiting (PONV) is defined as nausea and vomiting,
      which appears within 24 hours after the performance of a surgical/diagnostic procedure in
      general anesthesia. PONV is perceived as a complication of minor importance in perioperative
      medicine, nevertheless, it is one of the most frequent causes of morbidity in pediatric
      patients in the early postoperative period, associated with a number of adverse effects. The
      incidence of PONV in pediatric age is reported in scientific literature to be between 8.9 and
      42 percent. The pathogenesis of PONV is complex and has not been fully clarified yet. The
      development of PONV depends on individual and anaesthesiology risk factors, and the type of
      surgical procedure. The use of inhalation anesthetics demonstrably increases the incidence of
      PONV, especially in the course of the first two hours after the procedure. The need for
      inhalation anesthetic is individually variable, and it is not possible to empirically define,
      which dose will lead to an adequate depth of anesthesia. Excessively deep, as well as too
      shallow anesthesia may result in increasing the incidence of postoperative complications,
      including PONV. The depth of anesthesia and unconsciousness may be monitored with BIS
      (bispectral index). The investigators presume that optimization of the supply of inhalation
      anesthetic according to BIS, so-called BIGA (Bispectral index guided anesthesia) will lead to
      decreasing the incidence of PONV.

      Several clinical studies performed on the adult population have demonstrated that using BIGA
      leads to a decreased incidence of PONV in adult patients undergoing gynecological procedures.
      As far as pediatric anesthesiology is concerned, similar studies are still lacking.

      Inhalation anesthesia is also associated with another complication in the early postoperative
      period - so-called emergence delirium (ED). It is a condition of psychomotor restlessness,
      perception disorders, and excitation of the child observed after completion of anesthesia.
      The incidence of ED in the pediatric population anesthesia is between 10 and 80 percent, most
      frequently within the first 10-30 minutes after discontinuation of the administration of
      anesthetics. The condition is characterized by confusion, loss of orientation, crying,
      restlessness, and non-cooperation of the child. The causes of ED have not been fully
      clarified.

      One of the possible causes may be the rapid emergence of the child from anesthesia after
      discontinuation of the inhalation anesthetic. The incidence of ED is highest with
      Sevoflurane, which is the most frequently used inhalation anesthetic in pediatric anesthesia.
      Optimization of the depth of general anesthesia and decreasing the consumption of inhalation
      anesthetic may lead to decreasing the incidence of emergence delirium objectified according
      to the Paediatric Anaesthesia Emergence Delirium (PAED) score.

      The study has been designed as a prospective randomized clinical trial. Due to the use of the
      BIS monitor in the interventional arm, the study will not be blinded for the anesthetist. The
      total planned number of study subjects is 100. Patients will be randomly randomized upon
      arrival to the operating theatre (using the envelope method) into the interventional arm (BIS
      monitoring of the depth of general anesthesia), and into the control group (standard
      management of general anesthesia to minimum alveolar concentration (MAC) of 1.0). The target
      values of the depth of general anesthesia according to BIS are between 40 and 60.

      General anesthesia will be administered according to the following uniform anaesthesiology
      protocol:

      Inhalation introduction with Sevoflurane (8% on the vaporizer), in a carrier mixture of gases
      oxygen : air, with the flow of 41/min and oxygen concentration of 50%. In the intervention
      group, BIS will be introduced as soon as possible. After achieving a sufficient depth of
      anesthesia, a peripheral venous catheter will be introduced, followed with intravenous
      administration of opioid - Sufentanil in the dose of 0.2ucg/kg, and intravenous
      administration of Paracetamol in the dose of 15mg/kg. The infusion will be administered in
      the course of the surgical procedure - isotonic crystalloid solution Benelyte in the dose of
      10ml/kg/hour. Breathing passageways will be secured with an armed laryngeal mask, according
      to the standard procedure applied at the author's center. Considering the character of the
      study, no antiemetic prophylaxis will be administered. After completion of the surgical
      procedure and emergence from general anesthesia, the child will be transferred to
      post-anesthesia care unit (PACU), where, apart from the monitoring of vital functions, also
      the incidence of PONV and the PAED score (in the 10th minute, 30th minute, and 60th minute)
      will be observed. At the Ear-Nose-Throat (ENT) department, the authors will record the Baxter
      Retching Faces (BARF) scale in pre-determined time intervals, and the incidence of PONV in
      the course of the whole hospitalization.
    

Intervention name(s): BIS monitor; Standard care
Intervention type(s): Other; Other
Intervention description(s): BIS monitor is used to control and monitor the depth of general anesthesia.; Standard anesthesiology care according to the protocol of the study
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The study subjects will be randomized into two study arms.
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: postoperative nausea; postoperative vomiting; emergence delirium; bispectral monitor; pediatric anesthesia; adenoidectomy; general anesthesia