A randomized trial evaluating low doses of propofol infusion after intravenous ketamine for ambulatory pediatric magnetic resonance imaging

Comparison of effects of dexmedetomidine with ketofol and ketofol alone on quality of sedation in pediatric patients undergoing magnetic resonance imaging: A prospective randomized controlled double-blind trial

Background and Aim

Patient movement during magnetic resonance imaging (MRI) is the most frequent cause of artifacts and poor scan quality. Children cannot lie still. Thus, anesthesia is required to keep the child calm and immobile. This randomized double-blinded clinical trial compares the clinical effects of the addition of dexmedetomidine as premedication with ketofol on the quality of sedation. We hypothesized that the addition of dexmedetomidine would improve the quality of sedation.

Methods

A total of 132 children aged 6 months to 10 years were randomized into groups DK (dexmedetomidine-ketofol) and K (ketofol). DK received an intravenous bolus of dexmedetomidine (0.5 mcg/kg) as premedication 10 minutes prior. Both the groups were induced with ketofol (0.5 mg/kg), and sedation was maintained with propfol infusion (100 mcg/kg/min). The primary objective was the quality of sedation as assessed by the University of Michigan Sedation Scale. Image quality, requirement of rescue propofol dose, recovery, and adverse events were also studied. Data are given as median [interquartile range (IQR)] or frequency.

Results

All 132 children completed MRI scans. The DK group showed significantly better quality of sedation, 71% versus 47% of children, a median difference of 1 (-0.569 to -0.0969), P < .005, a better quality of scan, a reduced number of additional doses of propofol, and a decreased total dose of propofol. Hemodynamic parameters and recovery times for the two groups were similar. There were no significant side effects in both groups.

Conclusion

The quality of sedation and the quality of the MRI scan are greatly improved by administering dexmedetomidine (0.5 mcg/kg) 10 minutes before to induction. Additionally, this technique decreases the need of propofol and gives better hemodynamic stability without delaying the recovery time.

Comparison of airway collapsibility following single induction dose ketamine with propofol versus propofol sedation in children undergoing magnetic resonance imaging: A randomised controlled study

Background and Aims

Adequate sedation is essential for children undergoing magnetic resonance imaging (MRI) console. Propofol is commonly used for sedation, but it has the drawback of upper airway collapse at higher doses, which may be overcome by ketamine. This study was designed to evaluate the beneficial effect of ketamine on propofol in preventing airway collapse.

Methods

Fifty-eight children undergoing MRI were randomised to Group P (propofol bolus dose followed by infusion or Group KP (bolus dose of ketamine and propofol followed by propofol infusion). The primary aim is to compare the upper airway cross-sectional area (CSA) and diameters (transverse diameter [TD] and anteroposterior diameter [APD]) obtained from MRI during inspiration and expiration.

Results

Upper airway collapse as measured by delta CSA in mean (SD) [95% confidence interval] was statistically more significant between the two groups [at the soft palate level, 16.9 mm2 (19.8) [9.3-24.4] versus 9.0 mm2 (5.50) [6.9-11.1] (P = 0.043); at the base of the tongue level, 15.4 mm2 (11.03) [11.2-19.6] versus 7.48 mm2 (4.83) [5.64-9.32] (P < 0.001); at the epiglottis level, 23.9 (26.05) [14.0-33.8] versus 10.9 mm2 (9.47) [7.35-14.5] (P = 0.014)]. A significant difference was obtained for TD at all levels and for APD at the soft palate and base of tongue level.

Conclusion

Adding a single dose of ketamine to propofol reduced the upper airway collapse significantly, as evidenced by the MRI-based measurements of upper airway dimensions, compared to propofol alone.

Intramuscular ketamine provides better sedation and scan conditions in children undergoing magnetic resonance imaging: A single-blinded observational study

Objectives

The objectives of this study were to compare the quality of sedation provided by intravenous (i.v.) and intramuscular (im) ketamine for pediatric magnetic resonance imaging (MRI).

Materials and Methods

This study was a non-randomized, single-blinded, and prospective observational study. After receiving approval from the Institutional Ethics Committee, a total of 108 children aged 2-7 years were divided into two groups, with 54 children in each group. In the i.v. group, children received ketamine at a dose of 1.5 mg/kg intravenously, while in the im group, children received ketamine at a dose of 4 mg/kg intramuscularly. If a Ramsay sedation score of 6 (RSS-6) was not achieved, half of the loading dose of ketamine was repeated. In both groups, rescue propofol boluses of 1 mg/kg intravenously were administered whenever the child moved. The primary outcome measure was the quality of sedation, which was assessed by a blinded radiologist. The time taken to reach RSS-6, the number of rescue propofol boluses, the total time wasted in taking repeat sequences, and the time required to achieve a modified Aldrete score of 9 (MAS-9) were recorded.

Results

The im group demonstrated significantly better sedation quality. In the i.v. group, the time to achieve RSS-6 was significantly shorter, but it required more rescue propofol boluses to maintain sedation. The i.v. group also experienced a notable increase in the total time wasted during repeat sequences. On the other hand, the i.v. group exhibited a shorter time to reach MAS-9 compared to the im group.

Conclusion

The im group showed superior sedation quality when compared to the i.v. group. However, it is important to consider that the im group experienced a longer recovery time.

COMPARISON OF INTRAMUSCULAR VERSUS INTRAVENOUS KETAMINE FOR SEDATION IN CHILDREN UNDERGOING MAGNETIC RESONANCE IMAGING EXAMINATION

OBJECTIVE

The aim: To compare efficacy of intramuscular (IM) versus intravenous (IV) ketamine for sedation in children undergoing brain MRI scanning in children.

PATIENTS AND METHODS

Materials and methods: Children who required elective brain MRI were selected for this study. They were randomly divided into two groups; group I received 1.5 mg/kg IV Ketamine and group II received 4 mg/kg IM ketamine. In each group supplementary 0.1 mg/kg midazolam intravenously before positioning on MRI table was given. Patients were monitored for pulse rate, SPO2, and respiratory wave.

RESULTS

Results: Children who received IM ketamine had significantly shorter scan time and a greater success rate of sedation with first dose than the IV group. The proportions of scan interruption and scan repeat were significantly higher among the IV group than in the IM group. The scan time was longer among the IV group than in the IM group with significantly more scan interruption and repeat. Satisfaction with sedation as expressed by the technicians was significantly more in the IM group than in IV group (98.1% vs. 80.8%, P= 0.004).

CONCLUSION

Conclusions: Intramuscular ketamine injection was predicted to have a better sedative success rate and takes less time to complete than intravenous admin¬istration. This makes IM ketamine more appealing in certain conditions.

Incidence of complications in anesthesia applications during magnetic resonance imaging in pediatric patients

Purpose: The aim of this study was to investigate complications during sedation of pediatric patients undergoing Magnetic Resonance Imaging (MRI) to determine precautions to take to minimize complications while providing a safer environment for patients and healthcare workers. Materials and Methods: The files of consecutive patients taken for 6 months in the MRI unit of our hospital were reviewed retrospectively, and a total of 122 pediatric patients were included. Primary parameter in the study is set as peroperative and postoperative complication incidence. Interventions to treat, demographic data, ASA scores, accompanying diseases, agents and their doses for sedation, sedation and recovery time are the secondary parameters and their correlation to complication incidence is assessed. Results: Using the data of 122 patients, complication rate is found as 6.6% (8/122). During sedation, desaturation in 6, bradycardia and desaturation in 1 and airway obstruction in 1 of the patients was observed. Desaturation was seen in 2, bradycardia was seen in 1 of the patients during recovery. Use of ketamine didn’t decrease the dose of midazolam or propofol used for maintenance but decreased the dose of propofol used for induction. Conclusion: Complications may occur despite the presence of an experienced anesthesia team. It is important to anticipate such complications and intervene in a timely manner.

The frequency of emergence delirium in children undergoing outpatient anaesthesia for magnetic resonance imaging

AIM

The aim of this study was to investigate the effect on the occurrence of emergence delirium of propofol and ketofol with intranasal dexmedetomidine and midazolam applied as premedication to paediatric patients during magnetic resonance imaging (MRI).

METHODS

The study included children aged 2-10 years who received sedation for MRI, separated into four groups. Group MP (midazolam-propofol) received intranasal midazolam (0.2 mg/kg) for premedication and intravenous (IV) propofol (1 mg/kg) as the anaesthetic agent. Group MK (midazolam-ketofol) received intranasal midazolam (0.2 mg/kg) for premedication and IV ketofol (1 mg/kg) as the anaesthetic agent. Group DP (dexmedetomidine-propofol) received intranasal dexmedetomidine (1 mcg/kg) for premedication and IV propofol (1 mg/kg) as the anaesthetic agent. Group DK (dexmedetomidine-ketofol) received intranasal dexmedetomidine (1 mcg/kg) for premedication and IV ketofol (1 mg/kg) as the anaesthetic agent. The Paediatric Anaesthesia Emergence Delirium (PAED) scale was used to evaluate delirium. A PAED score ≥ 10 was accepted as delirium.

RESULTS

Statistical analysis was made of 140 paediatric patients. Delirium developed in 1.42% of all the patients, and in 5.7% of Group MP. The mean Aldrete and PAED scores were lower and the length of stay in the recovery room was shorter in Group DP than in the other groups. The need for additional anaesthetic was highest in Group DP at 94.3% and lowest in Group DK at 14.3%. The groups administered ketofol were observed to have a lower requirement for additional anaesthetic.

CONCLUSION

Delirium was seen at a very low rate only in the Group MP and it is difficult to say the best combination in terms of delirium frequency. However, intranasal dexmedetomidine and IV ketofol seem to be better and safer than the other groups in terms of the need for additional doses and the number of side effects. The addition of ketamine to propofol reduces the need for additional doses with a synergistic effect.

A non-randomized controlled study of total intravenous anesthesia regimens for magnetic resonance imaging studies in children

BACKGROUND AND AIMS

We studied the efficacy and safety of different total intravenous anesthesia used for pediatric magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Children of 1-7 years age (n = 88), undergoing MRI received a loading dose of dexmedetomidine 1 μg/kg over 10 min, ketamine 1 mg/kg, and propofol 1 mg/kg in sequence. University of Michigan Sedation Scale (UMSS) of 3 was considered an acceptable level for starting the scan. Rescue ketamine 0.25-0.5 mg/kg was given if UMSS remained <3. After the loading dose of drugs, some children attained UMSS = 4 or progressive decline in heart rate, therefore, did not receive any infusion. The rest received either dexmedetomidine (0.7 μg/kg/h) (n = 35) or propofol (3 mg/kg/h) (n = 38) infusion for maintenance. Ketamine 0.25 mg/kg was used as rescue. Sedation failure was considered if either there was inability to complete the scan at the pre-set infusion rate, or there was need for >3 ketamine boluses or serious adverse events occurred. Statistical Package for Social Sciences 20 was used for analysis.

RESULTS

Initiation of scan was 100% successful with median induction time of 10 min. Maintenance of sedation was successful in 100% with dexmedetomidine and 97.4% with propofol infusion. Recovery time (25 min v/s 30 min), discharge time (35 min v/s 60 min), and total care duration (80 min v/s 105 min) were significantly less with propofol as compared to dexmedetomidine (P = 0.002, 0.000, and 0.000, respectively). There were no significant adverse events observed.

CONCLUSION

Dexmedetomidine 1μg/kg, ketamine 1 mg/kg, and propofol 1 mg/kg provide good conditions for initiation of MRI. Although dexmedetomidine at 0.7μg/kg/h and propofol at 3 mg/kg/h are safe and effective for maintenance, propofol provides faster recovery.

Sedation for magnetic resonance imaging using propofol with or without ketamine at induction in pediatrics-A prospective randomized double-blinded study

INTRODUCTION

Deep sedation using propofol has become a standard technique in children. This double-blinded randomized clinical trial aims to compare the clinical effects of propofol-mono-sedation vs a combination of propofol and ketamine at induction and a reduced propofol infusion rate for maintenance in children undergoing diagnostic magnetic resonance imaging.

METHODS

Children aged from 3 months to 10 years scheduled as outpatients for elective magnetic resonance imaging with deep sedation were included. They were randomized into 2 groups, receiving either 1 mg/kg ketamine at induction, then a propofol infusion rate of 5 mg/kg/h or a propofol infusion rate of 10 mg/kg/h without prior ketamine. Time to full recovery (modified Aldrete score = 10) was the primary outcome. Further outcomes were quality of induction, immobilization during image acquisition, recovery, postoperative nausea and vomiting, emergence delirium using the Pediatric Anesthesia Emergence Delirium scale, vital signs and adverse cardiorespiratory events. All patients and parents as well as anesthetists, imaging technicians, and postsedation personnel were blinded. Data are given as median (range).

RESULTS

In total, 347 children aged 4.0 (0.25-10.9) years, weighing 15.6 (5.3-54) kg, ASA classification I, II, or III (141/188/18) were included. The ketamine-propofol group showed significantly shorter recovery times (38 (22-65) vs 54 (37-77) minutes; median difference 14 (95% CI: 8, 20) minutes; P < .001), better quality of induction, and higher blood pressure, but higher incidence of movement requiring additional sedative drugs. There were no significant differences in respiratory side effects, cardiovascular compromise, emergence delirium, or postoperative nausea and vomiting.

CONCLUSION

Both sedation concepts proved to be reliable with a low incidence of side effects. Ketamine at induction with a reduced propofol infusion rate leads to faster postanesthetic recovery.