The History of The CPAP Machine Continuous Positive Airway Pressure & Colin Sullivan
One of the earliest descriptions of CPAP was called a ’‘pulmonary plus pressure machine’’ in 1936 when Poulton described using a Hoover vacuum cleaner, to supply air at a positive pressure to treat patients with, ‘‘cardiac and bronchial asthma’’. He cautioned that: ‘‘the machine should be run for some minutes first of all to get rid of the dust’’. The intention of this machine was not for sleep apnea as it’s use today but to help with heart and lung problems. They had discovered CPAP but didn’t even know it at the time.
Colin Sullivan was born in 1945. He was trained as a Physician in Sydney Australia at the University of Sydney. He graduated in 1970. He completed his residency at the Royal Prince Alfred Hospital and received a doctorate in physiology. Physiology was measuring variables such as blood pressure and airflow at the time. He then went to Canada and trained under Dr. Philipson who had developed a model of measuring breathing in sleeping dogs. He then returned to Sydney and treated patients with Respiratory Failure and received the Cecile Lehman Mayer Research Award of the American College of Chest Physicians. This was awarded for original research on the influence of sleep on airway-smooth muscle tone.
Colin Sullivan looked for patients with sleep apnea. He wanted to experiment with them! They were hard to find at first. He couldn’t find any at the beginning. He sent up different models studying airway obstruction in animals and humans. The problem was how to measure airflow. They measured airflow by doing tracheostomy on dogs. He would occlude the airway and be able to test the airflow. At this time he was creating masks for dogs.
Sullivan’s first five patients were booked in at the hospital for a tracheostomy one night in 1979. This was the gold standard of treatment for Obstructive Sleep Apnea at the time. Four out of the five patients did that procedure. One of the patients refused the tracheostomy but agreed to do Sullivan’s CPAP experiment. Sullivan started this process at 9pm that night and expected to be out of the lab by 11pm as this would be a very short research experiment for him. He used a diving mask with medical grade silicone. As the patient was sleeping, the patient began to have apnea episodes right away even with positive pressure. Sullivan experimented by using different pressures and noted as he increased pressure, the apneas went away and as he went down in pressure that the apneas returned. This was the first official CPAP titration in history. Colin noted while the patient was sleeping that he went into REM sleep as well. When the patient woke up, he told Sullivan that he felt awake and alert for the first time in many years. What was supposed to be a 2 hour experiment ended up going all night and would eventually lead to CPAP being the gold standard of treatment over a tracheostomy.
A major hurdle that Sullivan encountered was creating a device for home use. They created a one night therapy in the hospital but now what. To make a CPAP Machine they had to put a circuit together something capable of giving adequate pressure to open the airway. Sullivan used a two Stage Vacuum Cleaner Fan, Setup in a box with a belt drive from an AC motor. Inlet and outlet tubes were separate from the motors so if the motor burnt out there would be no toxic gases going to the patient. Flow Generator Hitachi Portex Blower was a few hundred dollars and produces high flow and high pressure. The circuit had a very large pipe and a tee piece leaking most air to atmosphere. Fixed valve would leak pressure would be calculated for setting the pressures. The noise wasn’t a problem with the patients as the initial setups were people who exhibited severe sleep apnea. It took a very long time to take this therapy seriously. This wasn’t just the general population but the Medical Community itself. How could they take it seriously, your using a vacuum cleaner fan and tubes! The drive came from the patients itself. Theses patients haven’t been awake for years and they were filling refreshed and rejuvenated for the first time! Why wouldn’t they, they were suffering from severe hypoxia for so long. Another problem at the time too was there was no suitable masks for humans yet as Sullivan was only manufacturing masks for dogs. There were a lot of masks for anesthesia but coming up with one for CPAP was the issue. None of the masks would create a pressure seal or be used for sleep over night. Medical grade rapid sealing silicone was used to create the seal between the patient and mask. Sullivan eventually manufactured masks by taking casts of the nose.
Sullivan and his patients thought that this was a short term treatment. They kept asking when they were going have the cure and Sullivan would keep telling them, maybe by next year. Some how it was thought by many that CPAP would train your airway muscles and brain to function normally after short term use. For people who were overweight, Sullivan figured since CPAP would treat the metabolic problem that the patients would automatically lose weight and get off the device. He advised them to exercise as well.
Sullivan’s group followed patients around for 5 years and noticed the mean weight of the 100 patients stayed the same. By 1985 there were 100 people being treated on CPAP. Colin Sullivan and his team built all 100 machines and masks that were used in 1985. The masks lasted a long time made out of fiberglass with silicone. The silicone would peal off easily every morning and be ready to be used the following night.
Colin eventually established a clinic and space in the hospital. He had to fight to get space in the sleep lab. He was so busy making masks and machines that he recruited patients to help out too in the manufacturing process! As state earlier, Colin always believed that if the patients used this for a few months or less that they would be cured of sleep apnea. He thought that people could use it part time too and it would be effective. For instance, you can use it during the week and take the weekends off. He called this “Pulse Therapy”. He eventually figured out that wouldn’t work and to be on it full time was the proper therapy. Patients would get so attached to their machines. They would want to bring it everywhere because of how great they felt using it. One of Sullivan’s first patients tied a pink ribbon around their machine and called it LuLu!
Colin Sullivan always strived to found out why people get sleep apnea. He believes that people get it early in life. The structure of the airway is key to why people get it. Alcohol causes snoring and obstruction because it alters the tone in the airway. Colin believes that snoring vibration causes injury to the airway. It can start at an early age as a child and he believes that leads to sleep apnea as vibration decreases tone in the airway. Snoring damages the nerve endings, it damages the blood vessels. No snoring is healthy. His focus has been on children. He believes in removing the tonsils and adenoids as a child helps throughout life in preventing sleep apnea later in life. Cross bites and taking care of it at an early age with an orthodontist is something to consider too. In the next 30 years, Colin Sullivan believes CPAP will still be around just like reading glasses. He’s amazed how far technology has come with machines and masks.