Anesthesiology and Radiology: Safety and Imaging Choices
What this domain tests
This domain covers airway assessment, anaesthetic complications, resuscitation, sedation safety, and rational imaging. Radiology questions test modality choice, radiation, contrast risk, and recognition of time-critical findings.
Core rules
- Assess airway before anaesthesia: mouth opening, Mallampati, thyromental distance, neck movement, and dentition.
- Fasting reduces aspiration risk; emergency surgery requires rapid-sequence induction with cricoid pressure when appropriate.
- Spinal anaesthesia commonly causes hypotension from sympathetic blockade; treat with fluids and vasopressors.
- Malignant hyperthermia is triggered by volatile anaesthetics and suxamethonium.
- Choose imaging by the clinical question, urgency, radiation dose, and contrast safety.
Worked example
During general anaesthesia, end-tidal CO2 rises, the masseter muscles spasm, and tachycardia and hyperthermia develop. The diagnosis is malignant hyperthermia. Stop trigger agents, give 100% oxygen, call for help, give dantrolene 2.5 mg/kg, cool the patient, and treat hyperkalaemia and arrhythmias. The reasoning is that early dantrolene and trigger removal are life-saving; waiting for a confirmatory test is unsafe.
Traps
Sending an unstable patient for CT before resuscitation; ignoring rising end-tidal CO2; giving intravenous contrast without checking renal function and allergy history; missing a pneumothorax on a supine chest radiograph; using radiation in pregnancy without clear benefit.
Exam strategy
Ask whether the patient is stable, whether the test changes management, and whether the anaesthetic or contrast risk can be modified.