Daily Maintenance Tips for Anesthesia Machines

Why Daily Maintenance of Anesthesia Machines Is Critical

An anesthesia machine is a core piece of equipment that ensures patient safety during surgery and delivers anesthetic gases accurately. Adhering to routine daily maintenance is essential, primarily for the following fundamental reasons:

Ensuring Patient Safety

This is the most important reason. Regular inspection and cleaning of key components of the machine (such as the airway, breathing circuits, and masks), as well as confirming that alarm functions are operating correctly, help identify potential problems at an early stage. This can effectively prevent risks such as delivering incorrect gas mixtures to patients during surgery, causing inadequate ventilation, or missing critical equipment failure alarms.

Maintaining Continuity of Clinical Procedures

A sudden failure of the anesthesia machine during surgery is a serious issue. Daily maintenance involves checking, testing, and performing necessary care on the machine’s core components (such as gas supply connections, batteries, electronic circuit boards, and sensors), ensuring that these components operate reliably. This significantly reduces the likelihood of unexpected equipment shutdowns at critical moments during surgical procedures.

Extending Equipment Service Life

Like any precision medical device, an anesthesia machine requires proper care. Regular removal of dust and contaminants, lubrication of moving parts, replacement of worn gaskets and other consumables, and timely preventive maintenance can slow down equipment aging. Proper maintenance prevents minor issues from developing into major failures, allowing the machine to remain in service for a longer period and providing better long-term cost efficiency.

Compliance with Safety Regulations

Hospitals and regulatory authorities have clearly defined requirements for equipment management and medical safety. Implementing regular, documented maintenance of anesthesia machines is a fundamental requirement for meeting these standards. It also reflects the hospital’s commitment to quality management and responsible clinical practice.

Pre-use Visual and Functional Inspection

Before each use of the anesthesia machine, the following critical inspection items must be completed. These steps are simple to perform but are highly effective in preventing unexpected intraoperative problems:

Inspection of Hoses and Tubing Connections

Check all hoses (such as gas supply hoses and breathing circuit tubing) for integrity and absence of damage. Confirm that hose connectors are fully inserted into the machine interfaces and securely locked in place, with no signs of looseness or gas leakage.

Verification of Seal Integrity

Pay particular attention to sealing components such as rubber gaskets at pipeline interfaces. Check for cracks, deformation, or signs of aging and hardening. Any damaged seals must be replaced immediately.

Structural Integrity Check

Carefully inspect the machine housing, connectors, panels, and other structural components for cracks or damage. Gently shake connection points (such as sensor interfaces) by hand to ensure there are no loose components or missing parts.

Power Supply and Alarm System

• Connect the main power supply and observe whether the power indicator lights illuminate normally
• Test the backup battery (if equipped) and confirm that the battery level indicator shows sufficient charge
• Initiate the device self-test and confirm that all alarm indicators (such as low gas pressure and power failure alarms) illuminate and flash correctly

Gas Supply Confirmation

• Check the gas supply pressure gauges to ensure that readings are within the safe operating range (refer to the equipment manual for specific values)
• Open the gas cylinder valves and verify that there is sufficient remaining gas to complete the planned surgical procedure

The entire inspection process typically takes approximately 3–5 minutes. If any abnormalities are detected (such as audible gas leaks, loose connections, or alarm indicators failing to illuminate), the machine must be taken out of service immediately and technical personnel should be contacted.

A thorough understanding of anesthesia machine functions can further improve inspection effectiveness; refer to the article Analysis of Anesthesia Machine Components and Functions for additional guidance.

Daily Cleaning and Infection Control Measures

Maintaining the cleanliness and hygiene of the anesthesia machine requires the following key steps to be performed every day. Carrying out these steps in sequence ensures thorough cleaning while protecting the equipment:

External Cleaning After Handling or Use

After each transport or use of the equipment, wipe the outer surfaces of the machine with a slightly damp soft cloth to remove stains, blood residue, or dust. Focus especially on high-frequency hand-contact areas (such as cart handles, knobs, and screen edges).

Deep Disinfection of Contact Areas

Use certified surface disinfectants for the following components:

• Breathing circuit connectors, mask clips, and medication trays — disinfect after each patient use
• Gas control valves, hand wheels, and touch screens — disinfect at the end of each day’s clinical work▶ Apply disinfectant to a soft cloth before wiping; avoid spraying liquid directly onto the equipment.

Processing of Reusable Accessories

• Breathing bags and corrugated hoses: rinse under running water → soak in disinfectant solution → air-dry completely → store in sealed bags
• Metal instruments: process using high-temperature treatment in dedicated sterilization containers
• Rubber sealing rings: gently wipe with alcohol pads and allow to air-dry naturally (do not expose to direct sunlight)

Water Protection for Electronic Components

• Always unplug the power cord before cleaning
• Wring cleaning cloths until no water drips before wiping
• Use cotton swabs dipped in alcohol to gently clean precision interfaces (such as sensor ports)
• Never clean screens or keyboards while the device is powered on

Spending approximately 10 minutes at the end of each workday to complete these steps can significantly reduce the risk of cross-infection and protect sensitive internal components. Refer to the equipment manual for a list of compatible disinfectants. For more detailed procedures, see How to Ensure Patient Safety During Anesthesia Machine Operation.

Care of the Breathing Circuit and Ventilation System

Proper maintenance of the breathing circuit and ventilation system is directly related to patient ventilation safety. Follow the steps below carefully:

Breathing Circuit Inspection

Before each use:

• Fully extend all breathing hoses (corrugated tubing) and check for twisting, compression, or foreign object obstruction
• Run fingers quickly along the inner walls of the tubing to confirm there is no moisture or residual water droplets (pay special attention to the Y-connector)

Timely Removal of Condensation

During surgery, check every 30 minutes:

• Immediately empty the water trap if the water level exceeds one-third of its capacity
• Position the lowest point of the breathing circuit below the patient level to facilitate gravity drainage
• Do not exceed the maximum fill line when adding water to the humidifier

Valve and Filter Testing

Before starting daily clinical work:

• Inspiratory and expiratory valves: cover the Y-piece with the palm and quickly squeeze the breathing bag — normal performance is indicated by noticeable airflow resistance and rapid bag recoil
• Filters (if equipped):
  ✧Replace immediately when white filter elements turn gray or when breathing resistance increases
  ✧Metal mesh filters should be removed weekly and gently brushed clean using a soft-bristle brush
  If a gas leak sound is detected during testing, the machine must be shut down for inspection.

Replacement of Consumables

• Disposable breathing circuits and masks: replace for each patient (discard if packaging is damaged)
• Bacterial filters: replace every 48 hours or immediately if contaminated
• Sealing gaskets: replace immediately if hardening or cracking is observed

After replacement, perform a manual ventilation test to verify system airtightness.

Warning: Never reuse disposable consumables. Moist breathing circuits must be thoroughly air-dried before storage (in a shaded, well-ventilated area). Valve assemblies should be disassembled weekly for dust removal.

Monitoring System and Alarm Verification

To ensure that monitoring systems and alarm functions remain reliable at all times, the following operational procedures must be carried out in sequence:

Core Parameter Testing

• Pressure monitoring: block the breathing circuit outlet with the palm → observe whether airway pressure rises above 30 cmH₂O within 10 seconds → release and confirm rapid return to zero
• Gas concentration: expose the oxygen sensor to ambient air → confirm a reading of 21% ±2% (adjust according to local baseline at high altitude)
• Volume measurement: manually compress the breathing bag three times → displayed tidal volume variation on the screen should be less than 10% between cycles

Audible and Visual Alarm Trigger Verification

Testing requires two operators:

• One person disconnects the power supply or closes the gas source
• Another person confirms from a distance of 3 meters:
  ✧Continuous flashing of the red warning indicator
  ✧Alarm sound level exceeding 65 decibels (audible over operating room background noise)
  Test backup battery power-failure alarms on a monthly basis.

Common Alarm Causes

Golden Rules for Preventing False Alarms

• Hierarchical alarms: set “power failure” and “asphyxia” as highest priority (mandatory audible and visual alerts); downgrade “parameter fine adjustment” to on-screen pop-up notifications
• Delay optimization: set airway pressure alarm delay to 10 seconds (to exclude coughing interference); set oxygen concentration alarm delay to 3 seconds
• Range presets: tidal volume alarm limits = ±30% of estimated patient requirement (typically 400–700 ml for adults)

Use a test module weekly to verify alarm accuracy (requires connection to a dedicated calibration adapter). If the same alarm is triggered five or more times within 24 hours, the machine must be taken out of service for inspection.

Vaporizer and Gas Delivery System Inspection

The gas delivery system is the core power unit of the anesthesia machine. Follow the procedures below to ensure operational safety:

Vaporizer Installation Confirmation

• When installing the vaporizer, ensure that the positioning pins align correctly with the base slots
• Rotate the locking lever clockwise until a distinct “click” sound is heard
• Attempt to push the vaporizer horizontally — when properly locked, it should not move at all

Warning: An unlocked vaporizer may cause anesthetic agent leakage. If a sweet-smelling gas odor is detected, ventilate the area immediately.

Anesthetic Agent Safety Management

• Turn off the concentration control dial before filling
• Check the liquid level through the viewing window:
  ✧Maintain the level between the two scale lines
  ✧Refill if below the minimum level line
  ✧Never exceed the maximum safety line
• Use the manufacturer-approved filling funnel to reduce evaporation
  ✧If liquid spills occur, absorb immediately with a dry cloth to prevent corrosion of metal components

Gas Leakage Detection

• Pressure test: seal the breathing circuit outlet and maintain pressure at 30 cmH₂O (pressure drop should be less than 5 cmH₂O within 2 minutes to pass)
• Soap bubble test: apply soapy water with a brush to the following areas:
  ✧Vaporizer joints
  ✧Gas source hose connections
  ✧Edges of flowmeter glass covers
• Auscultation localization: move a stethoscope head along the tubing walls; mark any leakage points indicated by a “hissing” sound
• Ultraviolet visualization (optional): inject fluorescent agent into the gas pathway and inspect for fluorescent leak points under UV light in a dark environment

Routine Calibration Awareness

• Daily verification: set the concentration dial to the 1% position → actual output should be between 0.9% and 1.1% (measured with a gas analyzer)
• Environmental compensation: for every 1,000 meters of altitude increase, output concentration decreases by approximately 15% (manual adjustment of dip switches is required)
• Anti-interference Measures
  ✧Keep strong magnetic field devices at a distance (e.g., mobile phones more than 50 cm away)
  ✧Clean concentration dial contacts monthly using alcohol wipes without water

When Daily Maintenance Is Not Sufficient

When the anesthesia machine exhibits any of the following signs, professional maintenance intervention is required:

Indicators Requiring Service

• Persistent parameter deviations: for example, oxygen concentration deviates by more than ±10% from the set value after calibration, or tidal volume repeatedly fluctuates by more than ±15%
• Non-resettable alarms: the same alarm is triggered more than five times within 24 hours, or an alarm continues for more than 30 minutes without being cleared
• Hardware failure characteristics: deformation or cracking of mechanical components, burn marks on circuit boards, or unidentified liquid leakage from the control panel
• Performance degradation signs: prolonged startup warm-up time (greater than 15 minutes) or accelerated decline in gas output pressure

In such cases, immediately attach an out-of-service label and disconnect both gas and power supplies.

Importance of Regular Preventive Maintenance

Proactive Failure Prevention

• Perform deep calibration of gas sensors quarterly to avoid intraoperative concentration deviations
• Replace sealing components annually (especially vaporizer O-rings) to prevent hidden gas leakage

Cost-effectiveness Optimization

• Data indicate that consistent preventive maintenance reduces equipment failure rates by 67% and lowers annual maintenance costs per unit by approximately ¥12,000.
• Regulatory and Legal Compliance: Ensures compliance with international medical device management standards (such as ISO 80601-2-13) and mandatory regional regulatory requirements for annual comprehensive performance verification.

Selection of Authorized Service Providers

• Qualification verification: request manufacturer authorization certificates, with particular attention to coverage of the specific equipment model
• Parts traceability: replacement parts packaging should include anti-counterfeiting QR codes; scanning automatically generates electronic maintenance records
• Service closure: after maintenance, the provider must supply:
  ✧A test report including calibration data
  ✧Root cause analysis of the failure
  ✧Preventive recommendations for similar issues

Maintenance Record Management

• Record Content: Date / technician / detailed maintenance items / replacement part numbers / equipment status evaluation (graded A, B, C, or D)
• Retention Requirements
  ✧Paper records attached to the equipment maintenance card and sealed for water protection
  ✧Electronic records synchronized to the hospital equipment management system, with cloud backup retained for at least 10 years
• Audit Focus
  Regulatory inspections typically emphasize:
  ✧Continuity of preventive maintenance plan execution
  ✧Maintenance reports for equipment taken out of service for more than 72 hours
  ✧Consistency between part replacement records and failure documentation