Patients rely on anesthesia providers for safety and comfort during vulnerable moments. While your expertise is the primary safeguard, the equipment you use plays a massive supporting role. Anesthesia machines are complex workstations that deliver precise mixtures of gases and vapors, and their reliability is non-negotiable.
A daily machine check isn’t just a regulatory requirement; it is a fundamental ritual that ensures the technology won’t fail when a patient needs it most. Even the most advanced workstation is only as safe as its last inspection.
Let’s look at the essential components you need to inspect every single morning before the first case begins.
Gas Supply and Connections
The lifeline of any anesthesia workstation is its gas supply. You must verify that the pipeline pressures for oxygen, nitrous oxide, and air are within the normal range, typically between 50 and 55 psi. If the pipeline fails, your backup cylinders become the primary source of life support.
Open each cylinder to verify it is at least half full, then close it tightly to prevent slow leaks. Checking for leaks in the high-pressure system involves more than just a visual scan. You should perform a high-pressure leak test if your specific machine requires it.
Ensure that the hoses connecting the machine to the wall outlets are free from kinks and wear. A disconnected or leaking hose can lead to a sudden loss of gas pressure, triggering alarms and potentially interrupting oxygen delivery.
Breathing System Integrity
The breathing system is where the patient interacts directly with the machine. This circuit must be free of leaks to ensure that the delivered tidal volume actually reaches the lungs. Inspect the breathing tubes for cracks or holes, and ensure that all connections are tight.
The unidirectional valves, both inspiratory and expiratory, must move freely. Stickiness or incompetence in these valves can cause rebreathing of carbon dioxide, which can be dangerous. You also need to verify the condition of the carbon dioxide absorbent.
If the granules have changed color, usually to violet, they are exhausted and must be replaced. Using exhausted absorbent can lead to hypercapnia. Additionally, perform a low-pressure leak test to confirm the circuit can hold pressure.
Monitor Calibration and Accuracy
Your monitors are your eyes and ears. The oxygen sensor requires daily calibration to room air (21%) to ensure it reads accurately. A drifting oxygen sensor can lead to the delivery of hypoxic mixtures without alerting the provider.
Check the capnograph to ensure it registers a waveform when you breathe near the sampling line. Verify that the pressure gauges return to zero when the system is not pressurized. Flowmeters, whether mechanical or digital, should move smoothly throughout their range.
While checking anesthesia machine parts, pay close attention to the vaporizer mounting. Ensure vaporizers are locked in place, filled with the correct agent, and that the filler ports are tightly closed to prevent leaks.
Scavenge System Functionality
Waste gases must be removed effectively to protect everyone in the operating room. The scavenging system collects vented gases and directs them out of the environment. Check that the vacuum connections are secure and that the negative pressure relief valve functions correctly.
If the vacuum is too strong, it might suck gas out of the breathing circuit; if it is too weak, waste gases will pollute the room. Inspect the reservoir bag or collection system to ensure it is not occluded.
A blocked scavenging system can cause pressure to build up in the breathing circuit, leading to barotrauma. Conversely, an open system needs to be checked for obstruction to flow.
Ventilator Settings and Performance
Modern anesthesia machines often function as sophisticated ventilators. You need to verify that the ventilator bellows ascend and descend smoothly without sticking. If the machine uses a piston ventilator, ensure it moves freely.
Test the transition between manual and mechanical ventilation modes to confirm the selector switch works as intended. Set specific parameters, such as tidal volume and respiratory rate, and watch the test lung to confirm the machine delivers what you programmed.
Also, check that the pressure relief valve limits the airway pressure as expected. Malfunctions here can lead to hypoventilation or lung injury, so verifying mechanical performance is a top priority.
Alarm System Verification
Alarms are the safety net that catches deviations before they become disasters. You need to simulate conditions that trigger these alarms to know they will work. Disconnect the breathing circuit at the Y-piece to verify the low-pressure and disconnect alarms sound immediately.
Occlude the Y-piece to test the high-pressure alarm. Check the oxygen failure alarm by temporarily interrupting the oxygen supply. The machine should emit an audible warning and, in many designs, cut off nitrous oxide flow.
Volume and apnea alarms also need to be tested. Adjust the limits to ensure the alarm triggers when the parameters are exceeded.
