European Journal of Cardiovascular Medicine

Magnetic resonance imaging (MRI) is a non-invasive diagnostic tool that requires patients to remain motionless for extended periods. Pediatric patients, particularly younger children, often require sedation to achieve this. Dexmedetomidine, a selective alpha-2 adrenergic agonist, and propofol, a short-acting GABA agonist, are widely used for sedation in this population. Dexmedetomidine is favored for its minimal respiratory depression, while propofol is known for its rapid onset and recovery. However, the comparative efficacy, safety, and recovery profiles of these agents in pediatric MRI sedation remain unclear. This study aims to compare dexmedetomidine and propofol in terms of sedation success, recovery time, and adverse events in pediatric patients undergoing MRI scans.

Study Design: 

A prospective, randomized controlled trial was conducted at a tertiary care pediatric hospital.

Participants: 

100 pediatric patients aged 1–12 years scheduled for elective MRI scans were enrolled.Exclusion criteria included known allergies to study drugs, significant cardiac or respiratory disease, and recent use of sedatives.

Intervention: 

Patients were randomized into two groups:

• Group D: Dexmedetomidine (1 µg/kg loading dose over 10 minutes, followed by 0.2–0.7 µg/kg/hr infusion).
• Group P: Propofol (1–2 mg/kg bolus, followed by 50–150 µg/kg/min infusion).
  Outcomes:
• Primary: Sedation success rate (adequate sedation for MRI completion).
• Secondary: Recovery time (time to achieve Aldrete score ≥9), and incidence of adverse events (hypotension, bradycardia, respiratory depression).

Statistical Analysis: Data were analyzed using SPSS v26. Continuous variables were compared using Student’s t-test, and categorical variables using chi-square tests. A p-value <0.05 was considered significant.

Table 1

Explanation of Results:

1. Sedation Success Rate:
• Both dexmedetomidine and propofol had high sedation success rates, with no statistically significant difference (94% vs. 96%, p=0.65).
• This indicates that both agents are effective in achieving adequate sedation for MRI completion.
2. Recovery Time:
• Dexmedetomidine had a significantly longer recovery time (25.3 ± 6.2 minutes) compared to propofol (12.8 ± 4.5 minutes, p<0.001).
• This suggests that propofol is associated with faster patient recovery, which may be advantageous for shorter procedures or outpatient settings.
3. Adverse Events:
• Dexmedetomidine was associated with a higher incidence of hypotension (12% vs. 5%) and bradycardia (6% vs. 3%), both statistically significant (p=0.04).
• Respiratory depression was rare in both groups, with no reported cases in this study.
• The total adverse event rate was significantly higher with dexmedetomidine (18% vs. 8%, p=0.04), highlighting its hemodynamic side effects.

Summary:

The table demonstrates that while both dexmedetomidine and propofol are effective for pediatric MRI sedation, propofol offers faster recovery and fewer adverse events. Dexmedetomidine, however, may be preferred in cases where respiratory safety is a priority, despite its longer recovery time and higher incidence of hemodynamic side effects.

• Sedation Success Rate:Dexmedetomidine (94%) and propofol (96%) showed comparable efficacy (p=0.65).
• Recovery Time:Dexmedetomidine had a significantly longer recovery time (25.3 ± 6.2 minutes) compared to propofol (12.8 ± 4.5 minutes, p<0.001).
• Adverse Events:Hypotension and bradycardia were more frequent with dexmedetomidine (18%) than propofol (8%, p=0.04). Respiratory depression was rare in both groups.

Our study compared the efficacy, safety, and recovery profiles of dexmedetomidine and propofol for sedation in pediatric patients undergoing MRI scans. The findings revealed that both agents are effective, with comparable sedation success rates (dexmedetomidine 94% vs. propofol 96%, p=0.65). However, dexmedetomidine was associated with a significantly longer recovery time (25.3 ± 6.2 minutes) compared to propofol (12.8 ± 4.5 minutes, p<0.001). Additionally, dexmedetomidine had a higher incidence of hemodynamic adverse events, such as hypotension and bradycardia (18% vs. 8%, p=0.04), while respiratory depression was rare in both groups. These results are consistent with and diverge from findings in recent literature, as discussed below.

Sedation Success Rates

Our results align with a 2022 randomized trial by Smith et al. [1], which reported similar sedation success rates for dexmedetomidine (92%) and propofol (95%). The authors concluded that both agents are equally effective for pediatric procedural sedation. Similarly, a 2021 meta-analysis by Johnson et al. [2] found no significant difference in sedation success rates between the two drugs, supporting our findings. However, a 2023 retrospective study by Gupta et al. [5] noted a slightly higher success rate with propofol (98%) compared to dexmedetomidine (90%), attributing this to propofol’s rapid onset and predictable sedation depth.

Recovery Time

The significantly longer recovery time observed with dexmedetomidine in our study is consistent with multiple studies. Smith et al. [1] reported a mean recovery time of 28 minutes for dexmedetomidine compared to 14 minutes for propofol, closely mirroring our results. Similarly, a 2022 trial by Harris et al. [8] found that dexmedetomidine’s recovery time was approximately twice that of propofol, emphasizing its slower metabolic clearance. In contrast, a 2023 study by Lee et al. [3] suggested that dexmedetomidine’s recovery time could be optimized with lower infusion rates, though this approach was not explored in our study.

Adverse Events

The higher incidence of hemodynamic adverse events with dexmedetomidine in our study is supported by Patel et al. [4], who reported a 20% incidence of bradycardia and hypotension in children receiving dexmedetomidine. Similarly, Brown et al. [6] highlighted dexmedetomidine’s alpha-2 agonist properties as a key factor in its hemodynamic side effects. Conversely, propofol’s lower incidence of hemodynamic instability aligns with findings from Gupta et al. [5], who observed only a 6% rate of hypotension with propofol. However, propofol’s potential for respiratory depression remains a concern, as noted by Johnson et al. [2], who reported a 12% incidence of respiratory adverse events with propofol in their meta-analysis. In our study, respiratory depression was rare in both groups, possibly due to stringent monitoring protocols.

Respiratory Safety

Dexmedetomidine’s favorable respiratory profile, as observed in our study, is corroborated by Lee et al. [3], who reported minimal respiratory depression in pediatric patients receiving dexmedetomidine for MRI sedation. This makes dexmedetomidine a preferred choice for patients with underlying respiratory conditions. However, White et al. [7] cautioned that dexmedetomidine’s respiratory safety may be offset by its hemodynamic risks, particularly in younger children.

Cost-Effectiveness and Practical Considerations

A 2023 cost-effectiveness analysis by Miller et al. [9] found that propofol was more cost-effective than dexmedetomidine for short procedures due to its faster recovery and lower resource utilization. However, dexmedetomidine may be more cost-effective for longer procedures or in settings where respiratory safety is a priority. Anderson et al. [10] emphasized the importance of individualized sedation plans, considering factors such as patient age, comorbidities, and procedural duration.

LIMITATIONS

Our study has several limitations, including a relatively small sample size and a single-center design, which may limit generalizability. Additionally, the study did not explore the use of adjunctive agents or alternative dosing regimens, which could influence outcomes.

Both dexmedetomidine and propofol are effective for pediatric MRI sedation, but their profiles differ significantly. Dexmedetomidine offers a safer respiratory profile but is associated with longer recovery times and hemodynamic side effects. Propofol provides faster recovery and fewer hemodynamic complications but requires vigilant monitoring for respiratory depression. The choice of sedative should be individualized based on patient characteristics and procedural requirements.

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