Sevoflurane requirements during electroencephalogram (EEG)-guided vs standard anesthesia Care in Children: A randomized controlled trial.

STUDY OBJECTIVES: Intra-operative electroencephalographic (EEG) monitoring utilizing the spectrogram allows visualization of children's brain response during anesthesia and may complement routine cardiorespiratory monitoring to facilitate titration of anesthetic doses. We aimed to determine if EEG-guided anesthesia will result in lower sevoflurane requirements, lower incidence of burst suppression and improved emergence characteristics in children undergoing routine general anesthesia, compared to standard care. DESIGN: Randomized controlled trial. SETTING: Tertiary pediatric hospital. PATIENTS: 200 children aged 1 to 6 years, ASA 1 or 2, undergoing routine sevoflurane anesthesia for minor surgery lasting 30 to 240 min. INTERVENTIONS: Children were randomized to either EEG-guided anesthesia (EEG-G) or standard care (SC). EEG-G group had sevoflurane titrated to maintain continuous slow/delta oscillations on the raw EEG and spectrogram, aiming to avoid burst suppression and, as far as possible, maintain a patient state index (PSI) between 25 and50. SC group received standard anesthesia care and the anesthesia teams were blinded to EEG waveforms. MEASUREMENTS: The primary outcomes were the average end-tidal sevoflurane concentration during induction and maintenance of anesthesia. Secondary outcomes include incidence and duration of intra-operative burst suppression and Pediatric Anesthesia Emergence Delirium (PAED) scores. RESULTS: The EEG-G group received lower end-tidal sevoflurane concentrations during induction [4.80% vs 5.67%, -0.88% (-1.45, -0.31) p = 0.003] and maintenance of anesthesia [2.23% vs 2.38%, -0.15% (-0.25, -0.05) p = 0.005], and had a lower incidence of burst suppression [3.1% vs 10.9%, p = 0.044] compared to the SC group. PAED scores were similar between groups. Children <2 years old required higher average end-tidal sevoflurane concentrations, regardless of group. CONCLUSIONS: EEG-guided anesthesia care reduces sevoflurane requirements in children undergoing general anesthesia, possibly lowering the incidence of burst suppression, without altering emergence characteristics. EEG monitoring allows direct visualization of brain responses in real time and allows clearer appreciation of varying sevoflurane requirements in children of different ages.

Use of an Offsite Intraoperative MRI Operating Theater for Pediatric Brain Tumor Surgery: Experience from a Singapore Children's Hospital.

BACKGROUND: Intraoperative magnetic resonance imaging (iMRI) has been recognized as a useful adjunct for brain tumor surgery in pediatric patients. There is minimal data on the use of an offsite intraoperative magnetic resonance imaging operating theater (iMRI OT), whereby vehicle transfer of patients is involved. The primary aim of this study is to validate the feasibility of perioperative patient transfer to use an offsite iMRI OT for patients with pediatric brain tumor. Secondary objectives include the assessment of tumor resection efficacy and perioperative outcomes in our patient cohort. METHODS: This is a retrospective, single-institution clinical study of prospectively collected data from Singapore's largest children hospital. Variables of interest include issues encountered during interhospital transfer, achievement of surgical aims, length of stay in hospital, and postoperative complications. Our findings were compared with results of related studies published in the literature. RESULTS: From January 1, 2009 to December 31, 2018, a total of 35 pediatric operative cases were performed in our offsite iMRI OT. Within this cohort, 24 of these were brain tumor surgery cases. For all the patients in this study, use of the iMRI OT influenced intraoperative decisions. Average ambulance transport time from parent hospital to the iMRI OT was 30.5 minutes, and from iMRI OT back to the parent hospital after surgery was 27.7 minutes. The average length of hospitalization stay was 7.9 days per patient. There were no ferromagnetic accidents during perioperative iMRI scanning and no airway/hemodynamic incidents in patients encountered during interhospital transfer. CONCLUSIONS: In our local context, the use of interhospital transfers for access to iMRI OT is a safe and feasible option in ensuring good patient outcomes for a select group of patients with pediatric brain tumors.

Transtracheal jet oxygenation: Comparing the efficacy and safety of two self-made Y-connector devices with the ENK oxygen flow modulator™ in an infant animal model.

BACKGROUND: Self-made Y-connector jet-oxygenation devices with wide-bore expiratory port have been described but not evaluated in infant models. Little is known about the effect of oxygen flow rates on jet oxygenation via transtracheal cannula. AIMS: The aim of this study was to compare two self-made Y-connector jet-oxygenation devices against the ENK oxygen flow modulator™, and the effects of three different oxygen flow rates based on body weight, in both unobstructed and obstructed airways, on the time to re-oxygenate in a rabbit infant model. The aim was also to assess the effectiveness of an oxygen flow rate of 1 L/min, for re-oxygenation using ENK oxygen flow modulator™. METHODS: Nine rabbits were grouped in threes: Group 1 had a Y-connector attached to an intravenous infusion tubing, Group 2 the same Y-connector attached to a perfusion oxygenator tubing and Group 3, ENK oxygen flow modulator™. From oxygen saturations of 75%, the rabbits were jet oxygenated using their assigned device for 10 minutes at each flow rate of 1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min with their airways unobstructed and later, obstructed. Group 3 had additional experiments involving an absolute oxygen flow rate of 1 L/min. RESULTS: All devices resulted in rapid re-oxygenation within 40 seconds at flow rates of 1 L/kg/min. Oxygen flow rates beyond 1 L/kg/min in obstructed airways resulted in high airway pressures. All rabbits in Group 3 with obstructed airways died from barotrauma when jet oxygenated at a flow rate of 1.5 L/kg/min. When an oxygen flow rate of 1 L/min was used in Group 3, there was a failure to re-oxygenate to SpO2 90% within 120 seconds in some rabbits. CONCLUSION: Our animal model results suggest that self-made Y-connector jet-oxygenation devices with wide-bore expiratory port are efficacious and perhaps safer than ENK oxygen flow modulator™ in obstructed airways, and jet oxygenation with minimal oxygen flow rates starting at 1 L/kg/min or (age [years] + 4) L/min, whichever lower, should be considered.

Addition of bupivacaine 1.25 mg to fentanyl confers no advantage over fentanyl alone for intrathecal analgesia in early labour.

PURPOSE: a) To evaluate the effect of adding 1.25 mg of bupivacaine to intrathecal fentanyl on the duration of analgesia in an Asian population and b) to examine if the baricity of the local anesthetic at this dose has any bearing on the duration and quality of block. METHODS: Forty-eight parturients in early labour received combined spinal epidural (CSE) analgesia to evaluate a) the effect of adding 1.25 mg of bupivacaine to intrathecal (IT) fentanyl 25 microg on the duration of analgesia and b) the effect of baricity of intrathecal local anesthetic on the duration and quality of the block. Patients were randomly allocated to receive: IT fentanyl 25 microg plus normal saline (Group f, n=16), IT fentanyl 25 microg plus plain bupivacaine 1.25 mg (Group f+pb, n=16) and IT fentanyl 25 microg plus heavy bupivacaine 1.25 mg (Group f+hb, n=16). The two components of the IT injectate (total of 2.25 mL) were given sequentially. RESULTS: Group f+hb had the lowest sensory dermatomal block (T7 vs T4 (Group f), T5 (Group f+pb), P <0.01). There were no differences in the duration of analgesia and incidence of side effects among the groups. CONCLUSION: We found no advantage of adding 1.25 mg bupivacaine to fentanyl 25 microg. At this dose, the baricity of bupivacaine has no effect on the duration of analgesia.