history of respiratory therapy

history of respiratory therapy

The computer-controlled ventilators we know and use today operate on basic principles that are more than a century old. While the history of respiratory therapy dates back, there’s no denying that the advancements in the field have come a long way since then! 

What is Respiratory Failure?

To fully understand the miracle of respiratory therapy, we first need to grasp the gravity of respiratory failure. 

Respiratory failure is a condition that makes it difficult for a person to breathe on their own, resulting in the lungs’ inability to supply blood with oxygen. As breathing is an essential function of life; without sufficient breathing, our tissues and organs cannot work properly. 

According to NHIBI, when we inhale oxygen from the air into our lungs, we exhale out carbon dioxide, which is a waste gas made in the body’s cells. Improper breathing leads to a buildup of carbon dioxide. This buildup can damage tissues and organs and slow oxygen delivery to the body.

Some of the different causes of respiratory failure include:

  • Nerve and muscle disorders
  • Lung and airway diseases 
  • Fluid buildup in the lungs or pulmonary embolism 
  • Infections in your brain or spinal cord, lungs, or airways
  • Blocked airway when food or another object gets stuck in your airways
  • Chest or back injuries
  • Severe scoliosis
  • Severe allergies to food or medicine
  • Lifestyle habits, like smoking or using drugs or alcohol 

The Ventilator: The Medical Device You Hope You’ll Never Need

When encountering respiratory failure, the use of a ventilator is an extreme life-saving measure.  These are used when a patient’s lungs are not functioning properly on their own. Ventilators give a patient’s body a much-needed rest in addition to support, allowing their bodies to heal.

The use of ventilators goes back quite some time, and there are different types of ventilators on the market today. But how has technology changed over the years? 

Whole-Body Ventilators Lead to The Iron Lung

In an article written by Robert M Kacmarek, it is noted that the negative-pressure ventilator was the predominant device used to provide ventilatory assistance in the 19th and early 20th centuries. 

  • 1838: The earliest ventilator was described as a full body ventilator, or as a “tank ventilator”. The ventilator was an air-tight box, with the patient in a sitting position while negative pressure was established by manually pumping air into and out of the box. 
  • 1904: Following the Tank Ventilator were similar types of manually operated negative-pressure ventilators, like Sauerbrach’s negative-pressure operating chamber in 1904. In this chamber, the patient’s body, except for the head, was maintained inside a chamber which was large enough so that the surgeon was able to perform surgery while also in the chamber. 
  • 1907: Johann Heinrich Dräger and his son Bernhard introduced The Pulmotor, one of the only early devices for positive pressure ventilation in 1907. The Pulmotor was a transportable device that used a face mask to deliver oxygen until a set pressure was reached in the lungs, at which point the device switched to assisting the patient with exhalation. 
  • 1928: The Iron Lung, originally designed and built by Drinker and Shaw, but manufactured and sold by Emerson, was one of the most widely used ventilation devices of the early 20th century. It used negative-pressure techniques and worked by changing the pressure inside an airtight container. It expanded and contracted the chest, pulling air in and out of the lungs, and providing much needed support in the ICU for children suffering from polio for decades.

Advancements in Positive Pressure Ventilation are Made 

Just after the Polio epidemic of the 1950s, there was a movement away from negative-pressure ventilation.

This was mostly due to:

  1. Volume-targeted ICU/anesthesia ventilators beginning to appear. 
  2. The development of small, compact, intermittent positive-pressure breathing (IPPB) devices.
  3. The use of negative-pressure ventilation became too much, as they were large, heavy, and cumbersome.

The development of new positive-pressure breathing devices is credited to the need for pilots of late-WWII era jet planes requiring oxygen for their flights at high altitudes.

In the mid-1950’s, the Bird Mark 7 Respirator was developed by a former U.S. Army pilot, Forrest Bird. Many consider this device to be the first modern medical respirator, which led to many advancements in ventilator design and technology.

Non-Invasive Ventilators Through the Years

Though negative pressure, whole-body ventilators were most widely used at first, other non-invasive ventilators existed as well.

  • 1780: The bag and mask manual ventilator is introduced by Chaussier
  • 1887: A more sophisticated bellows with a mask was introduced by Fell
  • 1907: Dräger’s Pulmotor was first introduced, and for its time, was fairly sophisticated. The pneumatically operated positive-pressure device has been credited with saving thousands of individuals over its lifetime.
  • 1910: Green and Janeway create a device known as a “rhythmic inflation apparatus.” The patient’s head was placed into the apparatus and a seal was secured around the patient’s neck with positive pressure applied to the patient’s head. 
  • 1957: The Bird Mark series of ventilators were originally created to provide intermittent breathing treatments as opposed to long-term ventilation. Soon after, they began to be used for life support in both noninvasive and invasive ventilation.

Continued Advancements in Positive Pressure Ventilation Leads to Invasive Options

Another key part of the history of respiratory therapy is positive pressure ventilation. The development of ventilators for positive-pressure invasive ventilation began in the 1940s, and with each generation, became more advanced. Early models provided volume-control ventilation but lacked patient-triggered ventilation. Examples included the Morch ventilator, a simple piston ventilator, and the Engstrom ventilator, more sophisticated with double-circuit capabilities. 

The first-generation ventilators didn’t incorporate PEEP until the 1970s. The second generation introduced patient-triggered inspiration and basic alarms like high pressure and low tidal volume. Intermittent mandatory ventilation (IMV) emerged during this period. 

Third-generation ventilators, with microprocessor control, marked a significant advancement with extensive monitoring, waveforms, and various ventilation modes like pressure support and SIMV. 

Fourth-generation ventilators are the most complex, featuring numerous ventilation modes, closed-loop control, and capabilities for non-invasive ventilation (NIV) and neonatal ventilation. They also offer extensive monitoring and specialized management packages for weaning and assessments.

Michigan Instruments is Committed to Continued Advancements

Michigan Instruments Lung Simulators play a crucial role in advancing ventilator technology through various contributions that enhance training, testing, research, and product development in the field of respiratory therapy.

  • Training: We offer the Spontaneous Breathing Lung (SBL™), a sophisticated device that facilitates training for healthcare professionals and students. With the SBL™, users can create a wide range of breathing scenarios and patterns, making it an invaluable tool for educating professionals on new respiratory devices, ventilators, and therapeutic modalities.
  • Testing: The SBL™ is instrumental in testing and troubleshooting devices designed for spontaneous breathing patients. It enables thorough assessments, such as detecting the start of a breath and avoiding breath-stacking, ensuring the optimal performance of respiratory devices.
  • Research & Development: Our Lung Simulators are highly versatile for research applications. They have been utilized in diverse studies, from analyzing aerosol dispersion to evaluating the responsiveness of new ventilation. Researchers benefit from the precise simulation capabilities of Michigan Instruments’ equipment, enhancing the quality and accuracy of their research outcomes.

The SBL™ offers advanced control over breath rate, tidal volume, inspiratory time, and inspiratory flow pattern. Additionally, it has customizable settings and intuitive software, so users can simulate spontaneous breathing accurately. This makes it ideal for designing, testing, and training on non-invasive ventilation and oxygenation modalities.

Elevate Your Research Abilities with Michigan Instruments

Our commitment to innovation and excellence in respiratory care is evident in our comprehensive range of simulation tools and software solutions. We continue to empower healthcare professionals, educators, and researchers worldwide—contributing significantly to the evolution of ventilator technology and respiratory therapy practices.

For more information on our devices used in research environments worldwide, contact us today.