Post Anesthesia Emergence and Behavioral Changes in Children Undergoing MRI

Post Anesthesia Emergence and Behavioral Changes in Children Undergoing MRI: Comparative Study Using Propofol, Sevoflurane and Isoflurane

Children who receive general anesthesia may become agitated (emergence delirium) in the recovery period. This occurs more often after inhalational anesthetics, particularly sevoflurane and desflurane than after propofol. However, agitation after anesthesia in children may be difficult to distinguish from pain; accordingly studies are ideally designed during MRI to obviate the contribution of pain during emergence. Airway complications have been reported after LMA and isoflurane more commonly than with IV propofol and nasal prongs. Whether the airway complications were due to the LMA or the isoflurane was unclear. Therefore, this study was designed to study the incidence of 1. agitation after sevoflurane compared with IV propofol and 2. airway complications after LMA or nasal prongs.

180 children, ASA physical status 1 or 2 will be recruited for elective MRI scan. Randomized after consent is obtained to one of four groups. Anxiety will be assessed preoperatively using the modified Yale preoperative anxiety scale. Children will be accompanied by one parent to MRI scanner where monitors are applied. All children will have anesthesia induced with nitrous oxide and oxygen followed by sevoflurane until IV is established. Thereupon, they will be managed by their randomization assignment. The propofol pump will be concealed at all times. If propofol was used, it will be disconnected from the patient and residual propofol in the line flushed so prevent unblinding the patient's assignment. A blinded observer will be present to evaluate the patient when emergence begins. The single blinded observer will follow the patient from the MRI scanner through recovery room evaluating vital signs as well as emergence delirium (using the PAED scale). A PAED score > 12 at any time during emergence period will confirm the diagnosis of emergence delirium. After discharge from hospital, a post-discharge questionnaire will be completed at 12, 24 and 48 hours after discharge. All parents will be called to retrieve the questionnaire results after 48 hours after discharge from hospital.

After securing the IV, sevoflurane will be discontinued and a propofol infusion will be started at the dose of 300 mcg/kg/min depending on the child's age and neurologic status. A bolus of propofol will not be administered. Oxygen will be delivered via nasal prongs at 2 liters per minute. The infusion rate of propofol will be decreased to 250 after 15 min and then 200 mcg/kg/min also after 15 min. Supplemental IV boluses of Propofol (0.5 mg/kg) will be administered if the child moves or if signs of light anesthesia are noticed. The propofol infusion may also be increased in response to light anesthesia.

After securing the IV, weight appropriate LMA will be inserted and sevoflurane will be discontinued and a propofol infusion will be started at the dose of 300 mcg/kg/min depending on the child's age and neurologic status. Oxygen in air will be delivered via LMA. The infusion rate of propofol will be decreased to 250 after 15 min and then 200 mcg/kg/min after another 15 min. Supplemental IV boluses of Propofol (0.5 mg/kg) will be given if the child moves or exhibits signs of light anesthesia. The propofol infusion may also be increased in response to light anesthesia.

After securing the IV, weight appropriate LMA will be inserted and sevoflurane continued at 3% inspired concentration. Oxygen in air will be delivered via LMA at 2 lpm. The sevoflurane may be increased or decreased in 0.5% increments as needed.

After securing the IV, weight appropriate LMA will be inserted , sevoflurane will be discontinued and isoflurane will be administered at 2 % inspired concentration. Oxygen in air will be delivered via LMA at 2 lpm. Isoflurane may be increased or decreased in 0.5% increments as needed.

Delirium on emergence will be assessed using the PAED scale by a blinded observer in the post anesthesia period. A score >12 constitutes a diagnosis of delirium in children. The post anesthesia period is usually <2 hours after anesthesia.

All airway reflex responses including airway obstruction breath holding, coughing, laryngospasm, desaturation <92% for >15 s regardless of the cause, bronchospasm, secretions and hiccups

Inclusion Criteria: Age 2-12yrs, ASA Class I-II, Fasting, Unmedicated, Elective MRI scan Exclusion Criteria: Cognitive impairment, On psychotropic medications, Taking multiple (>2) antiepileptic medications, Requiring endotracheal intubation for GA