Who Needs Anaesthesia / Sedation for MRI
🎯 The scan needs a still patient for a long time
- Children & infants unable to cooperate; developmental delay / uncooperative adults
- Claustrophobia or anxiety in the long, enclosed bore
- Movement disorders, pain on lying still, or the need for prolonged immobility / breath-holds
- Critically ill / ventilated patients requiring transfer & ongoing support
Pre-Anaesthetic & MR Safety Screening
A standard pre-anaesthetic assessment plus MR-safety screening: pacemakers/ICDs (many now MR-conditional under strict protocols), cochlear implants, intracranial aneurysm clips, metallic foreign bodies (esp. intra-ocular), programmable shunts, drug patches with metal foil, and pregnancy. Fasting status, airway assessment and a plan for how the patient will be accessed complete the work-up.
Sedation vs GA, and Where to Deliver It
Sedation
- Dexmedetomidine (minimal respiratory depression) or propofol infusion for cooperative, low-risk patients / short scans
- Risk: airway obstruction & hypoventilation out of reach — full monitoring & rescue plan essential
General anaesthesia
- For long scans, unprotected airway risk, small children or the critically ill — secure the airway (LMA/ETT)
- Deliver via an MR-conditional anaesthesia machine & ventilator in Zone IV, or induce in an induction area (Zone III) and transfer, running a circuit through the waveguide
Practical setup: long breathing circuits & IV extension lines, MR-conditional infusion pumps, hearing protection, temperature management (cold room), and everything ferromagnetic left outside Zone IV.