Magnetic resonance imaging (MRI) is increasingly being used as a diagnostic tool for visualizing the brain and spinal cord. The examinations were performed under anesthesia to keep animals from moving, to prevent imaging artifacts.
One hundred fifty cases were anesthetized for MRI following this anesthesia protocol with tramadol (2–4 mg/kg) or morphine (0.3–0.5 mg/kg) IM administered 15–30 minutes prior to induction. Induction by diazepam (0.1–0.3 mg/kg) IV, maintenance with propofol infusion (100–400 μg/kg/h). Propofol infusion rates vary from 50–400 μg/kg/h, depending on the patient's condition.
In poor condition cases, the propofol dosage has to be decreased. In cases involving apnea due to patient's sensitivity to propofol or involving over dosage of propofol, propofol infusion should be stopped and breathing patterns monitored.
When using only propofol as an induction anesthetic agent, the propofol infusion rate must be higher dose compared to induction by propofol and diazepam. When the author used ear protection, the dosage of propofol infusion rate could be decreased and make a smoother anesthesia period. The advantages of using propofol are rapid onset, quick and smooth recovery and reliability when used in cardiovascular and neurological cases.
The disadvantages observed were apnea and cyanosis that the author prevented by implementing an orotracheal tube and a squeeze Ambu bag with oxygen. It was also found that hypothermia was prevented by applying heat and made the recovery period smoother.
The mortality rate was 1 in 150 due to the poor condition of the patient before administering anesthesia.