Ventilator Circuit Tubing Maintenance


Mechanical ventilation is an important method for keeping patients who are experiencing acute respiratory failure alive. This life-sustaining therapy has been around since the late 19th century, and it’s been used to help people breathe when their lungs become incapable of doing so on their own. Although modern hospitals very rarely use the mechanical “iron lungs” that helped people survive polio during the first half of the 20th century, new forms of medical ventilation that use ventilator circuit tubing are still used today to help patients breathe. 

The use of mechanical ventilators brought about the development of modern-day intensive care units, and it’s still used today for patients experiencing respiratory failure. Today’s ventilators force oxygenated air into the lungs through either non-invasive methods or intubation. These ventilation methods proved important as a last-ditch effort for those experiencing respiratory failure due to the novel coronavirus that caused the worldwide COVID-19 pandemic. 

Role of Medical Ventilation During the COVID-19 Pandemic

To bring COVID patients’ oxygen levels up, medical personnel first used non-invasive methods to push oxygen gently into the lungs through face masks, helmets, or nasal masks, which still allowed them to breathe out normally. When this wasn’t sufficient, hospitals would provide them with mechanical ventilation, which involved inserting a plastic tube through the trachea and vocal cords to deliver oxygenated air. In severe COVID cases, the novel coronavirus caused patients’ immune systems to respond by dilating blood vessels in their lungs, filling them with fluid that made breathing difficult. Ventilators helped by pushing more oxygen-rich air into patients’ lungs. 

Mechanical ventilation could cause further damage, however, as COVID patients often required a great deal of pressure to ensure enough oxygen entered their inflamed lungs. Dr. Tiffany Osborn – critical care specialist at Washington University School of Medicine in St. Louis – stated, “The ventilator itself can do damage to the lung tissue based on how much pressure is required to help oxygen get processed by the lungs.” 

Such medical ventilation helped elevate patients’ oxygen levels to near-normal levels. The process also added moisture and heat to the air entering patients’ lungs to match the bodies’ internal environment. This process involved heavy sedation to relax respiratory muscles and allow the machine to breathe for them. 

Key Maintenance Tips for Ventilator Tubing

Using triggering systems and high-tech patient breathing recognition to complement these ventilators, the majority of them require tubing, known as circuits, that allow oxygen to flow through them on demand. Along with this ventilator circuit tubing come heaters and humidifiers, suction catheters, filters and therapeutic aerosol generators. 

When patients are mechanically ventilated, their airways are subjected to cold, dry air. Because of this, patients often experience dryness in their noses and throats, along with inflamed airways that can cause additional medical difficulties. To prevent such issues, oxygenated air is heated and humidified by using a pass-over humidifier and heating system in the ventilator circuit tubing. When using mechanical ventilators for a patient with an acute respiratory infection (ARI), use of bacterial and viral filters is also recommended.

The circuit tubing is the key part of these medical ventilation systems requiring maintenance. Such tubing is generally made from corrugated plastic with universal connectors that attach the ventilator to an endotracheal tube, non-invasive interface, or tracheostomy tube. Problems that can develop within this circuit include:

  • circuit tubes kinking 
  • fluid gathering in filter
  • fluid pooling within the circuit
  • tube obstruction

These problems occur due to patients’ biting down on the tubes, sputum entering the circuit or kinks in the plastic tubing. To prevent colonies of unwanted microorganisms from growing inside the ventilator circuit tubing, it’s important to regularly clean and disinfects it. 

Contamination occurring within the tubing can be a real concern, especially for patients that require mechanical ventilation on an ongoing basis. Positive cultures of bacteria can grow, feeding off patients’ sputum and the inhaled gas. Because of this, ventilator circuit tubing requires changing every 48 hours. Respiratory therapy equipment that comes in contact with patients’ mucous membranes should also be cleaned thoroughly, with strong disinfectants applied after the initial cleaning. 

To keep the ventilator sanitary and sterile, it’s important to wipe down controls and the outside of equipment with disinfectants. Use a sodium hypochlorite solution at 500 parts per million (.05%) for non-metallic surfaces, and a sodium hypochlorite solution of 1000 parts per million (.1%) to disinfect the ventilator circuit tubing, making sure to flush the entire cavity. As the lines are not exposed to patients’ secretions, it’s not necessary to clean the pressure lines when using ventilators between patients. 

Normally the tubing through which patients exhale can be removed, with the expiratory end having a valve that controls escaping gas from the circuit. It may also have a water trap or device that measures airflow, or sometimes both. All this tubing should be disassembled before cleaning it with detergent. After rinsing it, the tubing should be disinfected and then sterilized. 

Sterilizing techniques in healthcare settings include:

  • Chemical sterilization involves submerging tubing into mixtures that contain chemicals such as bleach, ethylene oxide, hydrogen peroxide or ozone, though some can be harmful to humans. 
  • Dry heat sterilization is a slower but also reliable technique that requires more time and temperatures reaching over 340 degrees Fahrenheit. 
  • Plasma gas sterilizers use a hydrogen peroxide-based gas plasma at low temperatures to kill bacteria, fungi, spores and viruses; though costly, it’s extremely effective. 
  • Steam sterilization with autoclaves is typically the safest and cheapest method, using heat and intense pressure to destroy microorganisms.
  • Vaporized hydrogen peroxide sterilizers also use hydrogen peroxide vapor, using a generator to inject it into enclosures until it reaches the ideal concentration to sterilize equipment. 

At the very minimum, ventilator circuit tubing requires high-level disinfection regularly. 

Ventilator Circuit Tubing by M. M. Newman Corporation

Deep inside most ventilators resides a few small pieces of Heli-Tube® Spiral Wrap.  Most of the ventilators made during these crazy times required pieces of HT ⅛ UR or HT 3/16 C.  Many wonderful American companies transitioned their normal manufacturing into emergency ventilator manufacturing.  To help speed up the process M.M. Newman Corporation made the pieces these customers needed cut to the exact length for the ventilators they were building.  The demand for these cut-to-size pieces was very large and the companies needed these pieces immediately, so M.M. Newman Corporation needed to figure out how to cut these pieces very quickly by machine.  Some of the company’s veteran employees remembered seeing a very old wire and tubing cutter by the Eraser Company sitting around a few decades ago.  Once they located this machine and had their handy mechanic oil it up and fix a few broken parts, they were in business.  The beautiful antique machine was able to cut over twenty 6 inch pieces per minute.  As everyone knows, work environments became scary and stressful as we learned about how easily this Covid virus could spread.  The wonderful M.M. Newman Corporation team was extremely proud to be making these essential parts for ventilators.  It brightened our day to know we were helping keep people alive!