A Brief History of CPAP

The History of CPAP

By Admin

References to sleep apnea symptoms and related problems are found in literature going back hundreds of years, but the term sleep apnea only began to appear with regularity in the second half of the 20th century when doctors began to recognize the disorder as a root cause of its many symptoms. These symptoms, such as insomnia, fatigue, and severe snoring were treated separately in the past, but the core condition of sleep apnea often failed to improve, requiring an intensive and life-changing procedure such as a tracheotomy to provide the body with proper amounts of oxygen. With the invention of PAP therapy in the 1980s, doctors could finally treat sleep apnea at earlier stages before it progressed to the point of necessary surgeries. While some initial challenges, such as patient compliance, remain with us today, the CPAP machine has become the gold standard of sleep apnea treatment used by millions of patients all over the world.

The Beginning: Charles Dickens and the Pickwickian Syndrome

One of the most important advances in sleep apnea treatment was its recognition as a common disorder in the 1960s. Researchers in Europe as well as the U.S. were beginning to look closer at breathing problems in an effort to gain further understanding of its many debilitating health effects. In particular, a report entitled "Neurophysiological studies of Abnormal Night Sleep and the Pickwickian Syndrome,” authored by German physicians R. Jung and W. Kuhlo, gave researchers a new perspective on an often-overlooked set of symptoms. By tracking airflow levels and using polysomnograms to record apnea events, Jung and Kuhlo were able to produce quantitative data that documented the sleep apnea phenomenon. Inspired by a character description in The Pickwick Papers by Charles Dickens, the “Pickwickian Syndrome” was a blanket term used for sleep-related breathing conditions throughout the late 19th to early 20th century. But a lot of the early research on “Pickwickian” conditions focused mainly on weight issues as a primary cause. In The Pickwick Papers, Dickens describes a young man who is overweight, short of breath, and tired throughout the day, often falling asleep and snoring during his routine tasks. When doctors took a closer look at these symptoms among their “Pickwickian” patients, they began to notice the severity of sleep-related breathing problems among them. They also discovered that not all so-called “Pickwickian” patients were overweight, but all suffered from respiratory failure events throughout the night. In time, the cessation of breathing during sleep became the focus of treatment, and sleep apnea, a term meaning “want of breath,” became the label of choice.

The Golden Age of Sleep Research

One of the reasons that sleep apnea was overlooked for so long was the common misdiagnosis of the symptomatology. Doctors often associated these symptoms with weight problems in those with a high body mass, while diagnosing smaller or thinner patients with other sleep-related conditions such as depression (or "melancholia"), narcolepsy, or insomnia. By the 20th century, apnea symptoms were well known, but not well understood. What changed things, for the most part, was the increase in studies on sleep and sleep-related health concerns. The explosion of research into the second half of the century led to many discoveries that revolutionized the medical profession.

The Birth of PAP Therapy

The idea of sustained positive airway pressure was first used as an experimental treatment of asthma and related heart problems. It was in1936 that Doctors E.P. Poulton and D.M. Oxon used what they called a “pulmonary plus pressure machine” to treat “cardiac and bronchial asthma.” They describe the machine as a vacuum cleaner with a mask, and they shifted pressures manually to treat the symptoms. Though Doctors Poulton and Oxon did not use the device to treat sleep apnea, their use of positive airflow to treat respiratory defects would later inspire the invention and development of modern PAP therapy as we know it.

In 1978, Doctor Christian Guilleminalt, the first editor-in-chief of the journal Sleep, discovered the collapse and obstruction of airways as the primary cause of sleep apnea syndromes. After spending several nights in a clinical research center to monitor blood pressure changes in sleeping patients, he and his fellow researchers recognized the apnea events and noticed immediate spikes in resting blood pressure as a result. At the same time in Australia, Doctor Colin Sullivan was doing his own sleep apnea research using positive airway pressure on canine subjects. Trained as a physician at the University of Sydney, Dr. Sullivan was able to test his idea of nasal-airway pressure therapy when his patients began to demand the experimental therapy as a chance to avoid tracheotomy and relieve the symptoms. Using fiberglass to make casts of nasal profiles, Dr. Sullivan was able to create customized masks for his patients. He then used the Drinker respirator design, now known as the “iron lung,” to create a motorized air pressure device with a vacuum fan, ventilation tubes, and controlled flow settings. The masks originally had to be attached with adhesive for the duration of each therapy session. Like the iron lung, the original PAP devices made a considerable amount of noise, but the patients at the time had severe conditions and were desperate for sleep. During his initial treatments, Dr. Sullivan experimented with pressure levels to achieve the ideal amount for a complete reduction of apnea events. He describes how he was able to turn the apnea off with his machine, but as the pressure requirements varied between patients, the titration of the airflow became a routine task of therapy setup. Once he was able to eliminate apnea events for his patients, they would awake reporting feelings of relief and restfulness. Using CPAP, patients were no longer awakened in the night, and a return to normal blood oxygen levels gave them a sense of renewal. Sullivan and his team would later improve his mask and pump design, but it was a difficult task, as the mask portions had to be made for each individual patient.

As the number of patients increased, the amount of work going into the treatment increased exponentially. In 1981, Dr. Sullivan published his groundbreaking sleep apnea research in the journal Lancet. Titled “Reversal of Obstructive Sleep Apnoea by Continuous Positive Airway Pressure Applied Through the Nares,” the paper included a description of his experiments and their positive results, attracting considerable attention from the medical community regarding his claims. But his team still needed to develop something for home use. What he had accomplished in a clinical setting did not necessarily apply to the home environment. So the experiments continued. His research team constructed 100 CPAP machines for 100 patients, each with a customized silicone mask tailored to the individual profile of each patient. But this time they focused on ease of use, and gave each patient instructions and training so they could take their treatments home for regular nightly use. By 1985, Dr. Sullivan had enough support to enter the commercial market with his CPAP machine. The company Respironics, based in Pittsburgh, became the first to introduce the devices on the medical supplies market, followed by the company Baxter International, known today as ResMed. These two companies, in competition with one another, would create new and innovative designs for the next 30 years, aiming at improved comfort, ease of use, and a major reduction in the noise output of the machines.

The 1990s

Although the use of CPAP would soon surpass tracheostomy as the frontline treatment for sleep apnea, the commercialization of the machines was not an overnight accomplishment. Despite the effectiveness of the treatment, there were many challenges involved with the promotion, manufacturing costs, and medical insurance coverage of the devices. Most importantly, they were not cheap to make. Both doctors and patients had to be convinced that CPAP was an effective solution to sleep apnea syndromes. And secondly, the early masks were not the most comfortable thing to wear at night. To improve the masks, Dr. Sullivan created self-sealing cushions that he called “Bubble Masks,” making the PAP therapy experience much more comfortable and easier to manufacture. It was now possible to standardize mask production while still maintaining a comfortable fit that improved upon the tailored approach of his original models. Originally, Dr. Sullivan believed his PAP therapy treatment to be a potential cure for sleep apnea, meaning that if patients used the devices long enough and consistently enough, they could be cured of sleep apnea. His hope was that people would be weaned off of CPAP the same way they were weaned onto it. But he soon realized that PAP therapy alone was not likely to be a cure. Instead, he urged lifestyle changes along with the therapy to help minimize the symptoms as much as possible. He would later tell the National Sleep Foundation that CPAP was “like reading glasses,” used when necessary for the long term. While Dr. Sullivan continued his sleep apnea research, his PAP machines would not only go on to become the gold standard of sleep apnea treatment, but would be used for other medical purposes as well, including the management of respiratory failure in both clinical and emergency settings.

BiPAP and ASV

Following Dr. Sullivan’s mask innovations in the early 1990s was the development of bi-level technology for PAP systems, allowing the machines to use two pressure levels at various intervals during therapy. Bilevel systems, called BiPAP for short, would expand the scope of PAP treatments to other breathing disorders such as Chronic Obstructive Pulmonary Disease, or COPD. BiPAP would also improve the treatment options for those who had difficulty breathing with standard CPAP therapy. BiPAP is sometimes called Auto-PAP or APAP, but should not be confused with Adaptive Servo-Ventilation (ASV), which was developed early in the 21st century. With ASV came the most advanced PAP therapy system yet . ASV actually auto-titrates the pressure settings to follow the patient’s breathing patterns in real time, one breath after another. Like BiPAP or Auto-PAP, ASV was used for multiple purposes and remains an additional option for those with particular breathing needs. The precision of ASV has been extremely effective for those with central sleep apnea syndromes and Cheyne-Stokes Respiration, which can lead very easily to heart failure.

The Future of PAP

Today, the technological revolution of the 21st century continues to push medical devices like the CPAP machine to new frontiers, shrinking the devices and reducing their sound to near silence. As a result, sleep apnea has become a highly treatable condition that almost everyone knows about. Support networks, sleep centers, and PAP device marketplaces make it easy for anyone to seek out the right system for their needs. And as therapy data becomes more detailed, convenient, and precise, it also becomes more accessible, allowing patients to better understand their own treatment and get more involved as a result.