Open-label, prospective, randomized comparison of propofol and sevoflurane for laryngeal mask anesthesia for magnetic resonance imaging in pediatric patients

Abstract

Background: Magnetic resonance imaging (MRI) for pediatric patients often requires deep sedation or anesthesia because they must remain completely immobile for a relatively long period to obtain high-quality images.

Objective: The aim of this study was to compare the effectiveness of propofol i.v. or inhalation of sevoflurane anesthesia with the laryngeal mask airway (LMA) for children undergoing MRI.

Methods: Children aged 2 to 6 years with American Society of Anesthesiologists' physical status of I to II who were scheduled for MRI were enrolled in this study and randomly divided into 2 groups. The propofol group was administered propofol 4 mg/kg i.v. followed by infusion of 150 microg/kg x min(-1). Patients in the sevoflurane group were induced with sevoflurane 8% by face mask and maintained with an air/oxygen mixture followed by sevoflurane 1.5%. Data recorded included age, weight, scan time, LMA insertion, removal, and recovery times, hemodynamic parameters, complications, pediatric anesthesia emergence delirium (PAED) scale score, child movement, and MRI interruption. A higher PAED score indicated a higher level of delirium.

Results: Eighty-eight children were enrolled and randomized to treatment. Nine children were excluded from analysis due to protocol violations. After completion of the study, there were 37 children in the propofol group (male/female, 18/19; mean [SD] age, 42.1 months; weight, 15.2 [4.9] kg; scan time, 20.5 [4.6] min) and 42 in the sevoflurane group (male/female, 15/27; mean [SD] age, 44.4 [26.1] months; weight, 15.1 [5.2] kg; scan time, 20.6 [4.8] min). No significant differences were found between the study groups with regard to age, weight, scan time, and hemodynamic parameters at baseline and during the study period. Mean LMA insertion, removal, and recovery times were significantly longer in the propofol group (4.8, 5.2, and 8.8 minutes, respectively) than in the sevoflurane group (3.3, 2.5, and 3.9 minutes, respectively) (P < 0.05). The mean PAED score in the propofol group was significantly lower than that in the sevoflurane group (mean [SD], 6.1 [4.0] vs 10.5 [3.7]; P < 0.05). The percentage of MRI interruption in the propofol group was significantly higher than that in the sevoflurane group (4 [11%] vs 0, respectively; P < 0.05). No episodes of hypotension or bradycardia occurred during the study, and alterations in the propofol infusion rate or sevoflurane concentration were not necessary. One child vomited in the sevoflurane group during the postoperative period.

Conclusions: This small study found that sevoflurane, at the doses used in this study, provided shorter induction and faster recovery times than i.v. propofol for LMA anesthesia in these selected children undergoing MRI. The percentage of MRI interruption in the propofol group was significantly higher than that in the sevoflurane group. Sevoflurane was associated with a significantly higher score on the PAED scale, indicating greater emergence delirium.