Comparing the efficacy and safety between Propofol And Dexmedetomidine for sedation in claustrophobic Adults undergoing Magnetic resonance imaging (PADAM)

Recruitment steps: 1. Patients were recruited from the MRI room or registry. 2. Recruited patients were slotted into a designated time for research studies under the bio-imaging department or following their original date and time of appointment depending on which one would be earlier or convenient to the patients. 4. Patients were explained the risks and purpose of study and written informed consent was taken prior to procedure. 5. Following the trial number, patients were randomized to either: Group A: The attending anaesthetist would administer Propofol (10mg/ml) infusion, using Target Controlled Infusion (TCI) with Schnider’s pharmacokinetic model for target effect site. Drug boluses and infusions are administered according to ideal bodyweight. TCI infusion was started at a rate of 1.5 mcg/kg until the steady state was achieved then titrated with increment of 0.1mcg/kg to achieve Ramsay Sedation Score (RSS) of 3. OR Group B: The attending anaesthetist would administer Dexmedetomidine (4mcg/ml) infusion and administered according to ideal bodyweight. Loading dose of 1mcg/kg/min was given within 10 minutes and infusion was started at the rate of 0.2mcg/kg/hr and titrated by increment of 0.1mcg/kg/hr and above to achieve RSS of 3. Dosing was instituted according to the dexmedetomidine (Precedex) guidelines. It was a double-blinded study whereby both patients and the attending radiographer (the same person who would perform the Spielberg Anxiety and Visual Anxiety Scores). On the day of the re-scheduled MRI scan: 1. Patient was fasted for at least 6 hours before the scheduled scan. 2. No premed was given. 3. An Intravenous cannula (20-22G) was inserted to start 500mls of crystalloid as fluid maintenance. 4. Patient entered the scanning room for 5 minutes before being asked to answer the Spielberger Straits Traits Anxiety Score and Visual Anxiety Score to determine their anxiety levels pre-examination by the attending radiolographer. 5. Standard monitoring with non-invasive blood pressure (NIBP), heart rate, Pulse Oxymetry and electrocardiogram (ECG) was applied, monitored and recorded throughout the scan. 6. Oxygen 3L/min via nasal prong was given to the subjects. 7. A fully equipped emergency trolley and airway management was on standby in the MRI room vicinity at all times. 8. The sedative agent according to the randomized group was given intravenously and titrated until patient achieved RSS of 3. 9. Time when the drug infusion started and the time taken to achieve RSS score of 3 were recorded. 10. Once RSS of 3 was achieved, patient entered the MRI tunnel. 11. Any failed scans were recorded and reasons documented. 12. Adverse events during the scan such as i) Drop in blood pressure > 20% from baseline or requires vasopressors ii) Bradycardia <50 beats per min iii) Desaturation < 95% requiring airway and ventilation support iv) Over sedation were recorded and managed appropriately by the attending anaesthetist. After the scan: 1. Patient was monitored in the recovery bay. 2. After 5 minutes in recovery, patient was asked again to answer the Spielberger Straits Traits Anxiety Score and Visual Anxiety Score to determine their anxiety levels post examination by the same attending radiographer. 3. Vital signs and sedation scores were recorded for every half an hour until ready for discharge. 4. Any side effects or complications including hypotension, bradycardia or respiratory instability were managed accordingly. 5. The patient will be allowed home by the anaesthetist once all discharge criteria were fulfilled: v) Fully conscious vi) Hemodynamically stable vii) Able to perform physical activity without support or with minimal support. viii) No nausea or vomiting 6. Before going home, patient was asked to fill in a Patient Satisfaction Score form. 7. All data collected was analyzed statistically using SPSS.