Common troubleshooting and routine maintenance of anesthesia machines

An anesthesia machine is an advanced medical device that can transport, control and assist a patient's breathing of a variety of gases and volatile anesthetics, while also adjusting the patient's consciousness and pain level during surgery.
The birth of anesthesia machines can be traced back to the 19th century, when the concept of anesthesia was first proposed. In the early days, anesthesia machines were simple devices consisting of an ether-soaked sponge and a mask. However, these original devices lacked precision and posed significant risks to patients due to inconsistent dosing and lack of safety mechanisms. As the field of anesthesia advances, so does the technology behind anesthesia machines. In the mid-20th century, the development of precision vaporizers and the incorporation of oxygen and nitrous oxide flow meters revolutionized anesthesia delivery. Standardization of components and safety features such as pressure relief valves and fail-safe mechanisms are also critical to ensure patient health during surgery.
With the advent of technology, anesthesia machines have evolved further to integrate monitoring functions and automation systems. Modern anesthesia machines now feature advanced monitors that continuously measure vital signs such as heart rate, blood pressure, and blood oxygen saturation. These monitors provide real-time data to anesthesiologists, allowing them to make informed decisions and adjust anesthesia levels accordingly.
In addition, the introduction of closed-loop anesthesia systems has improved the safety and precision of anesthesia delivery. These intelligent systems use algorithms to automatically adjust dosing based on patient parameters, reducing the risk of human error and optimizing patient outcomes.
During the development of the anesthesia machine, several challenges and lessons emerged. An important lesson learned is the importance of rigorous testing and quality assurance to ensure the accuracy and reliability of these complex systems. The integration of automation and artificial intelligence requires thorough validation and strong safety protocols to minimize the possibility of errors and failures.
Additionally, ongoing education and training for healthcare professionals is critical to keeping pace with technological advancements. Anesthesiologists and medical staff must be proficient in the operation and troubleshooting of modern anesthesia machines in order to provide optimal patient care.

YSENMED has compiled some common faults of anesthesia machines for your reference only. If there are any omissions, you can add them in the comment area~

1. Failure phenomenon: The patient’s breathing circuit is leaking.
Possible Causes:
1. The APL valve is not closed during manual control;
2. The soda lime tank is not installed tightly;
3. The threaded pipe is damaged or the joint is loose;
4. The valve cover is not tightened;
5. The manual/automatic transfer switch fails.
Solution: 
1. Close the semi-closed APL valve;
2. Reinstall the semi-closed APL valve;
3. Replace new pipes or reinstall pipelines;
4. Retighten the valve cover.

2. Failure phenomenon: The foldable bag at the end of expiration cannot be extended to the top.
Possible Causes: 
1. The selected respiratory rate is too fast when the tidal volume is large;
2. The patient’s breathing circuit leaks;
3. The flow control switch is not turned on;
4. The pressure value of the overflow valve is incorrectly adjusted.
Solution: 
1. Reset the appropriate breathing frequency;
2. Check the air leakage point as described in the above example;
3. Turn on the flow control switch.

3. Failure phenomenon: The folding bag does not compress during air supply or the compression range is not enough.
Possible Causes:
1. The anesthesia machine working mode switch is still in the manual position;
2. The speed-determining oxygen supply switch failed and leaked;
3. The windbox glass cover is damaged;
4. Airway obstruction.
Solution:
1. Adjust the working mode switch to the machine control position;
2. Replace the windbox glass cover;
3. Remove airway obstructions.

4. Failure phenomenon: The pressure in the airway is too high during manual breathing.
Possible Causes:
1. Pressure reducer failure, manifested as normal output pressure when no-load, but when oxygen is supplied quickly, the pressure is lower than 0.25Mpa;
2. The setting value of the bleed valve is not adjusted correctly.
Solution:
1. Replace the pressure reducer;
2. Adjust when the flow rate reaches 1L/min, and adjust the output of the purge valve to an appropriate range.

5. Failure phenomenon: Airway pressure upper limit alarm.
Possible Causes:
1. The pipeline at the patient end is not smooth;
2. The patient’s airway is blocked;
3. The upper limit of airway pressure is set too low;
4. Changes in ventilation parameters.
Solution:
1. Check the patient-side pipeline and correct it for smoothness;
2. Check the patient’s respiratory status;
3. Recalibrate the alarm setting value;
4. Recalculate and adjust ventilation parameters.

6. Failure phenomenon: Airway pressure lower limit alarm.
Possible Causes:
1. The patient-end gas pipeline leaks;
2. The alarm setting value is too high;
3. Changes in patient compliance.
Solution:
1. Check the pipeline and correct the leaking part;
2. Reset the alarm value;
3. Check patient compliance status.

7. Failure phenomenon: There is no indication of airway pressure parameters.
Possible Causes:
1. The connecting tube between the suction channel and the pressure sensor is loose or connected incorrectly;
2. The air source is exhausted.
Solution:
1. Reconnect the connecting pipe between the suction channel and the pressure sensor;
2. Replace the air source.

8. Failure phenomenon: There is a large deviation between the tidal volume and the set value.
Possible Causes:
1. The flow sensor is damaged;
2. The flow sensor needs to be calibrated;
3. The exhaled gas pressure sampling tube is blocked.
Solution:
1. Replace the flow sensor;
2. Check and recalibrate the flow sensor;
3. Replace the exhaled gas pressure sampling tube.

10. Failure phenomenon: Positive end-expiratory pressure occurs when PEEP (continuous positive end-expiratory airway pressure) is not used.
Possible Causes:
1. The skin has high gravity;
2. Improper gas compensation flow setting;
3. Airway obstruction.
Solution:
1. Reduce the weight of the skin;
2. Use appropriate flow control;
3. Clear all parts of the airway.

Routine maintenance of anesthesia machine
1. Regularly carry out daily inspection and maintenance, including cleaning devices, cleaning up water, calibration data, etc.
2. Carry out regular inspection and maintenance of the entire machine, promptly reinforce the air pipe joints, and replace aging pipes, filter membranes, rubber rings, etc.
3. Prepare a certain amount of common accessories, such as flow sensors, quick connectors, various specifications of air pipes and rubber rings, etc.

The above are some common faults of anesthesia machines compiled by YSENMED for your reference only. If there are any omissions, friends can add them in the comment area.