Why Do Breathing Circuits Fail During Surgery?

Why Breathing Circuit Failures Create Severe Surgical Risks

The Core Functions of the Breathing Circuit

· Oxygen Delivery Channel: Continuously delivers oxygen into the patient’s lungs to sustain life.

· Anesthetic Gas Pathway: Ensures precise delivery of anesthetic agents into the patient’s body to maintain a pain-free state.

· Waste Gas Exhaust System: Rapidly removes exhaled carbon dioxide from the patient to prevent internal accumulation.

Once this pathway is interrupted, the patient may face hypoxia within 30 seconds. If anesthetic gas delivery is interrupted, the patient may regain consciousness during surgery.

The Lethality of Minor Failures

Even minor issues in any link of the circuit can trigger a chain reaction:

· Micro-leaks → Insufficient anesthetic gas concentration → Patient regains consciousness during surgery

· Partial tube obstruction → Decreased oxygen delivery efficiency → Rapid decline in blood oxygen saturation

· Loose connections → Obstructed waste gas discharge → Carbon dioxide accumulation damages organs

These changes may escalate to a critical condition within 2–3 minutes, leaving physicians with almost no time window for corrective action.

The Impact of Failure

· Patient Safety Risks: Failures may lead to inadequate oxygen supply, increasing the risk of brain injury. Abnormal anesthetic gas delivery may cause the patient to regain awareness during surgery.

· Interruption of Surgical Workflow: Surgeons must suspend the operation to address the malfunction, prolonging operative time and increasing infection risk. Emergency rescue measures divert the attention of the medical team.

· Institutional Liability Risks: Failures may trigger medical disputes and damage institutional reputation. Continuous maintenance negligence increases legal risk and the probability of safety incidents.

The Three Most Common Causes of Breathing Circuit Failure

Abnormal operation of the Breathing Circuit generally originates from three primary aspects:

(1) Human Error

The system must be correctly assembled and operated. Common operational issues include:

· Improper installation or incomplete tightening of connections, leading to gas leakage.

· Excessive pulling, kinking, or insecure fixation of tubing, impairing gas flow.

· Failure to perform the mandated full-system leak test and pressure check before surgery, resulting in undetected problems in advance.

(2) Product Quality Issues

Equipment defects themselves represent another key cause of failure. These typically involve:

· Poorly designed connectors or interfaces, insufficient mechanical strength, or non-standardized dimensions, causing loose or imperfect fitting.

· Inferior material quality of tubing, connectors, or sealing rings, making them prone to deformation, aging, or rupture, resulting in chronic leakage or sudden failure.

· Unstable performance of filters (such as HME), which may be rapidly blocked by secretions during surgery. Inadequate overall manufacturing control leads to performance inconsistency among components.

(3) Surgical and Environmental Factors

Surgical complexity and environmental changes challenge the stable operation of the system:

· Long-duration surgeries (for example, exceeding 5 hours), or repeated changes in patient positioning required by surgical procedures, may subject the tubing to additional stress or cause accidental disconnection.

· In certain environments (such as humid regions or operating rooms with limited air conditioning), large amounts of water vapor can condense and accumulate inside the tubing. If not removed in time, this may obstruct airflow or damage internal sensors.

· Special surgical conditions (such as restricted pulmonary function due to patient body habitus, highly sensitive ventilation parameters in pediatric patients, or laparoscopic surgeries requiring pneumoperitoneum) require higher airway pressures. Sustained high pressure imposes stricter demands on system sealing performance and material strength.

“Everything You Need To Know About The Anesthesia Breathing Circuit” helps you understand the fundamental and detailed aspects of the Breathing Circuit.

Early Warning Signs That Anesthesiologists Must Never Ignore

During anesthesia, specific warning changes must be closely monitored. When the following signals are observed, operations must be stopped immediately and thorough troubleshooting must be conducted:

Sudden Changes in Airway Pressure or Tidal Volume

Under normal conditions, pressure curves exhibit continuity. When leakage, obstruction, or changes in tube position occur, pressure may rise or fall significantly. Abnormal changes in exhaled gas volume may indicate obstruction in the delivery pathway or abnormal dissipation points and must be corrected promptly.

Unexpected Elevation in Carbon Dioxide Levels

When this value rises beyond expected levels, it may be due to incomplete elimination of exhaled gases with re-inhalation. In such cases, valve function and circuit airtightness must be checked to rule out failure of carbon dioxide absorption devices. If sustained for an extended period, this may lead to harmful gas accumulation within the patient’s body.

Anesthesia Machine Alarms

Equipment alarms must never be treated as temporary disturbances and ignored. They may indicate abnormal pressure, leakage, airflow obstruction, or other severe problems. Medical staff must immediately stop and identify the triggering cause, confirming whether the issue involves tube disconnection, valve blockage, sensor malfunction, or other fundamental components.

Visible Condensation, Collapse, or Fracture

Excessive condensation droplets formed inside the tubing due to humid environments or temperature differences must be removed promptly. Corrugated tubes may collapse or become compressed, impeding airflow. If connectors develop cracks or become completely detached, this constitutes a severe threat. These visible issues can rapidly trigger actual failure and must be addressed immediately.

What Happens If the Breathing Circuit Fails?

When the Breathing Circuit cannot function properly, it triggers a series of negative chain reactions that have profound impacts on both the patient and the medical institution:

Hypoxemia and Hypercapnia

When gases cannot normally enter and exit the patient’s lungs, the first consequence is a reduction in the amount of oxygen available to organs and tissues throughout the body. This may result in insufficient oxygen supply to vital organs such as the brain and heart. Meanwhile, exhaled carbon dioxide may accumulate within the circuit and be re-inhaled by the patient, leading to elevated carbon dioxide levels in the body that cannot be effectively eliminated. The rapid progression of both conditions may compromise the stability of the patient’s vital signs.

Interruption of Anesthetic Drug Delivery

Circuit damage or leakage disrupts the stability and accuracy of anesthetic gas flow. As a result, the patient may be unable to continuously receive the designated concentration of anesthetic gases required to maintain the surgical anesthesia state. This may cause premature recovery of pain perception, intraoperative awareness, or failure to achieve the expected depth of anesthesia, thereby affecting the surgical operating environment. The anesthesiologist must spend additional time adjusting dosages to maintain balance.

Increased Aspiration Risk

Reduced system sealing allows oral secretions, vomitus, or external foreign matter to be more easily aspirated into the trachea and lungs. When the patient is under anesthesia and loses self-protective reflexes, aspiration—once it occurs—may enter deep lung tissue and trigger severe inflammatory reactions or even acute airway obstruction. This places significant pressure on postoperative recovery.

Institutional Reputation and Legal Risks

Major related complications in patients (such as intraoperative awareness, brain injury, and pneumonia) receive heightened scrutiny. These events may trigger strong complaints from family members, medical dispute mediation, or even judicial litigation. Lapses in medical equipment management may lead to accountability reviews. After hospitals and Breathing Circuit suppliers are jointly involved in incident investigations, they face reputational damage and long-term challenges to institutional trust.

Practical Preventive Measures in Daily Clinical Application

To effectively reduce the incidence of Breathing Circuit failure, the following key operational points should be consistently implemented in clinical practice:

Pre-Use Leak and Connection Testing

At the start of every surgery, the entire circuit must be checked for leakage using pressure testing tools in strict accordance with procedures. All interfaces should be secured by tightening to their specified positions. This step is the most direct safeguard for identifying human assembly errors or interface degradation.

Tube Fixation and Damage Avoidance

Use tubing of appropriate length and dedicated fixation devices to secure the Breathing Circuit in positions that are not easily subjected to compression, especially avoiding surgical operating areas or heavy object movement paths. The tubing should remain extended with adequate allowance for mobility, preventing excessive tension, stretching, or accidental dislodgement caused by patient repositioning.

Use and Replacement of HME Filters

Clearly distinguish the application scenarios and time-limit requirements of different types of filters. For patients with large volumes of secretions or during prolonged surgical procedures, filter patency should be checked in advance, and blocked components should be proactively replaced before formal replacement indications appear. Ensure that filtration efficiency meets standards to reduce the risks of abnormal humidity and airflow obstruction.

Adherence to Safety Checklists

Before anesthesia induction, during critical phases of surgery, and after equipment transitions, rely on detailed step-by-step checklists to complete fundamental setup tests one by one (such as ventilator/manual control switching and verification of effective ventilation modes). Checklist-based verification systematically prevents configuration errors caused by human negligence.

Staff Training and Fault Simulation

Conduct practical training focused on correct circuit assembly, common fault identification, and emergency response procedures. All participating personnel must memorize key alarm response steps and enhance on-site collaborative troubleshooting and resolution capabilities through simulated abnormal equipment operation scenarios.

What to Focus on When Purchasing a Breathing Circuit

Authoritative Certification Marks

Priority should be given to confirming that the product packaging displays ISO medical device quality system certification (manufacturing process control), CE European medical market access approval (safety standard compliance), and FDA U.S. market authorization documents (clinical safety validation). These marks serve as the legal foundation for basic equipment safety and quality control. Suppliers should be required to provide copies of valid certification documents within their effective periods.

Compatibility with Anesthesia Machines

Special attention should be paid to testing the compatibility between the connection ports and the mainstream anesthesia equipment commonly used in target hospitals (such as Dräger, GE Datex-Ohmeda, and other leading brands). Hands-on verification is required to confirm that no gaps remain after tightening the connectors, in order to avoid intraoperative gas leakage risks caused by specification mismatches. Suppliers may be requested to provide compatibility test reports.

Material Tolerance and Biological Safety

Tubing materials must pass anti-kinking tests (no deformation after 360-degree twisting) and long-term compression elasticity testing. Odor assessment through sample sniffing and elevated temperature testing (placement at 40°C for 24 hours) should confirm that no chemical solvent odors are released. Material safety data reports must include cytotoxicity test results.

Sterilization and Packaging

Suppliers should be required to specify the exact sterilization method (such as ethylene oxide or radiation sterilization) and verify packaging integrity. Random sampling should be conducted to check for sealing defects, and simulated transportation vibration tests should confirm the effectiveness of the sterile barrier system. Each individual package must clearly display the sterilization batch number and expiration date.

Quality Traceability and Stability

Review the supplier’s quality control process documentation with particular emphasis on confirming: whether the minimum packaging unit carries a unique traceability code; whether destructive random sampling tests (such as connector tensile strength testing) are conducted across different batches; and whether quality consistency reports for the most recent 12 months can be provided.

Key Takeaways for Global Buyers

The essence of Breathing Circuit failure lies in a preventable systemic risk. Most incidents originate from the combined effects of human operational errors (such as omission of pre-use checklists and non-standardized connection procedures) and inferior products (materials prone to fracture and excessive connector tolerances). Locking in suppliers with full ISO/CE/FDA certifications at the procurement stage (such as CN MEDITECH, which focuses on medical respiratory equipment) ensures baseline quality. On the clinical application side, strict implementation of standardized procedures such as leak testing, fixation protocols, and filter replacement can simultaneously reduce both equipment failure probability and the risk of associated legal liability.