Anesthesia Equipment, Machine Checkout, and Breathing Systems
What the exam tests
Anesthesia Equipment, Machine Checkout, and Breathing Systems tests the daily checkout, gas supply, vaporizers, circuits, suction, alarms, and safe use of circle and Mapleson systems.
Core rules and concepts
- Follow a systematic checkout: backup oxygen cylinder, pipeline pressure, oxygen failure alarm, vaporizers, breathing system leak test, unidirectional valves, CO2 absorbent, suction, airway devices, monitors, and scavenging.
- Pin index safety system: oxygen is 2–5, nitrous oxide 3–5, and medical air 1–5. Colour coding is secondary and varies.
- The circle system uses unidirectional valves, a reservoir bag, adjustable pressure-limiting valve, CO2 absorbent, and fresh-gas inflow. Low flows conserve agent and humidity but require leak-free equipment.
- Mapleson systems differ in fresh-gas inlet position and depend on high fresh-gas flow; the Bain circuit is a coaxial Mapleson D.
- Exhausted CO2 absorbent causes a rising inspired CO2 baseline, not a normal square capnogram.
Worked example
During a low-flow circle case at 1 L/min, the capnogram baseline climbs from 0 to 8 mmHg and inspired CO2 appears. Reasoning: the absorbent is exhausted or channelled, or a unidirectional valve is stuck, so exhaled CO2 is rebreathed. Increase fresh-gas flow, ventilate with a self-inflating bag if needed, and replace the absorbent.
Traps
Do not skip the leak test or test with the Y-piece open. Do not ignore a silent oxygen alarm. Do not assume a green cylinder is full; check pressure and pin index. Do not use a circle system with a known valve fault. Do not forget to check suction and scavenging before induction.