The Effects of Bispectral Index Monitoring on Hemodynamics and Recovery Profile in Mentally Retarded Pediatric Patients Undergoing Dental Surgery

Forty children between the ages of 6-16 yr, ASA physical status I,II and III, scheduled to undergo dental rehabilitation under general anesthesia, were studied in this prospective and randomized study. Patients with moderate mental retardation were also enrolled in this study. The children were randomized, by using a computer-generated block randomisation, into 2 groups. In Group 1 (n=20), the depth of anesthesia was monitored by the Bispectral index (BIS) and BIS scores was maintained between 45-65 by titrated sevoflurane. In Group 2 (n=20), BIS monitoring was not performed, and general anesthesia was maintained with one minimum alveolar concentration (MAC) of sevoflurane in oxygen by hemodynamic parameters. All patients were expected to fast 6-8 hours before dental surgery, and no one premedicated. Routine monitors (consisting of a pulse oximeter, 3-lead ECG and a non-invasive blood pressure cuff and BIS monitoring only group 1) were applied. Baseline measurements were obtained and 3 min of pre-oxygenation was performed before the induction of general anaesthesia. In both groups general anesthetic management consisted of face mask inhalation induction with sevoflurane 8% in oxygen and then intravenous (IV) catheter placed. Intravenous rocuronium 0.6 mg/kg was given to facilitate tracheal intubation. After, making sure that all four TOF responses of the Adductor Pollicis disappeared intubation (with an appropriately sized nasotracheal tube) was then performed. After induction, volume controlled mechanical ventilation (tidal volume adjusted to 6-8 mL/kg with no application of positive end expiratory pressure and respiratory rates were adjusted to achieve an end-tidal carbon dioxide of 30 to 35 mm Hg.) was initiated. Anaesthesia was maintained using sevoflurane in an oxygen / air mixture and remifentanil (0,25 microg/kg/min). When mean blood pressure (MBP) varied by more than +/- 20% from the baseline the infusion rate of crystalloid solution was increased. If this was not sufficient, the inspired anesthetic concentration was reduces and anesthesia was maintained in this way in Group 2. In group 1, anesthesia was maintained by BIS scores between 45-65. Paracetamol (10 mg/kg) were given IV to attenuate postoperative pain. BIS score, HR, BP, oxygen saturation (SpO2), ETCO2 and TOF values was continuously recorded from awake status to tracheal extubation (basal, after induction, after intubation, at the start of surgery, every 10 minutes during surgery, at the end of surgery, during eye opening in response to verbal stimulus or painful pinching and after extubation). Remifentanil infusion stopped and all patients were weaned of sevoflurane as the surgery neared conclusion (when started control of bleeding). Hence, when the surgery ended, it coincided with the sevoflurane being turned off. Sugammadex (2mg/kg) was used for neuromuscular recovery in all patients when anesthesic agents turned off. When neuromuscular recovery was completed and adequate depth of breathing was reached (after the return of adequate ventilator drive, tidal volume > 6 ml/kg, respiratory rate > 12/min, normal breathing patterns and good oxygenation [SpO2 > 98%]) tracheal extubation was done. Following tracheal extubation, patients were cared for in the recovery room. In the PACU, the criteria for discharge (which included consciousness, normal vital signs, no pain and no nausea or vomiting) was the same for all patients. For measuring pain, Non-communicating Children’s Pain Checklist – Revised (NCCPC-R) was used in PACU. This pain score was noted. A total Score of 7 or more indicates a child has pain and a non steroidal anti inflammatory drug (0,4 mg/kg) were given IV to attenuate pain. The duration of the surgical procedure (skin incision to skin closure), anesthesia (time of induction to time of discontinuation of anesthetic agents), PACU stay was noted. To evaluate recovery profile time to spontaneous ventilation (the time between anesthetic discontinuation and beginning of spontaneous ventilation), extubation (the time between anesthetic discontinuation and extubation), open eyes (the time between anesthetic discontinuation and eye opening in response to verbal stimulus or painful pinching) and PACU discharge was also noted.