Effect of midazolam and dexmedetomidine on heart ventricles function using MRI - a pilot randomized study
Abstract
Objective: Comparison of changes in ventricular function during sedation with midazolam and dexmedetomidine by magnetic resonance imaging (MRI), assess the feasibility of the implemented study protocol and determine the sample size of our randomized study. Design: A pilot randomized study.
Setting: District hospital. Materials and methods: The study included participants who met the inclusion criteria.
Enrollment was by the envelope method: 8 participants in each group. After signing the informed consent, cardiac MRI was performed before and after sedation.
During the examination, the blood flow velocity through the mitral valve during the early (E diast) and late (L diast) phase of diastole, the flow velocity through the aortic (Ao flow) and pulmonary (Pul flow) valves were recorded. A monitor recorded values of mean blood pressure (MAP), pulse (P), blood oxygen saturation (SpO2) in 5-minute intervals.
Results: Dexmedetomidine decreased MAP (82.5 mmHg +- 6 vs. 75.5 mmHg +- 7.2, p-value 0.027). P a SpO2 in both groups were without significant changes.
Midazolam sedation led to worsening in E diast (234.5 mL.s-1 +- 93.5 vs. 207.6 mL.s-1 +- 87.6, p-value 0.012) whereas dexmedetomidine didn't have a significant impact on E diast. L diast was not influenced by the sedation technique in both groups.
Dexmedetomdine sedatoin led a decrease in Pul flow (87 cm.s-1 +- 17.1 vs. 73.5 cm.s-1 +- 10.5, p-value 0.016) indicating a decrease in right ventricle output. Conclusion: The implemented study protocol is feasible.
Midazolam sedation worsens early filling of the left ventricle compared to dexmedetomide. Dexmedetomidine leads to a greater decrease in mean blood pressure and worsens, when compared to midazolam, right ventricle output.