Sunday, March 11, 2012

x 1955-1985: The IPPB Revolution x

"This 1960s Monaghan Ventalung ad is a part 
of our IPPB Virtual Museum.http://museum.aarc.org/gallery/ippb/,"
said an AARC Facebook post on 3/25/16
If you were a respiratory therapist anytime between 1955 and 1985 you're familiar with Intermittent Positive Pressure Breathing.  While the machines were initially introduced to be used as respirators, physicians soon decided they were useful for delivering respiratory medicine and preventing and treating post operative atelectasis and pneumonia.   The IPPB revolution was born.

The first machine capable of providing positive pressure breaths over an extended period of time without the assistance of a person was introduced in 1948 as the Monaghan Ventalung Respirator.  These machines were used during WWII as ventilators.  They were nice because the alternative was to use an Ambu-bag to keep people breathing, in which case the provider of breaths would have to rotate through two hour shifts around the clock.

It was likewise during WWII that Dr. Forrest Bird became interested  in creating a device to allow pilots to fly higher.  It was believed if a pilot could fly higher he could avoid the enemy, and stay out of range of their ammunition.  (1)

This quest lead to the first  pneumatic respirator, meaning it was completely driven by compressed air and no electricity was required.   It was a small, portable green box, and all you had to do to start it up was plug it into a 50 PSA oxygen source, such as an oxygen tank or piped in oxygen system, and turn up the flow.   It was portable and provided a nice, easy means of providing mechanical breaths. For this reason the Mark 7 became the most popular such machine, although the  Mark 1,  Bennet TV-2P Vivian, Monaghan Ventalung Respirator, and the Manley Ventilator provided viable alternatives.

It was quickly learned that when used as a ventilator there were four problems:

  1. No manometers or devices to indicate how much of a tidal volume you were delivering
  2. Bird Mark 4 (1955)
  3. No alarms to indicate you were giving too much pressure or the patient was disconnected
In order to accommodate these disadvantages, respiratory therapists had to continuously check on the machines.  They would also have to be placed close to nurses stations so they could be closely monitored.  I believe this was the main reason hospitals started creating intensive or critical care units.  

It didn't take long for physicians to come up with another use for these machines.  It was believed that by providing positive pressure breaths with medicine for 5-15 minutes three to four times per day that certain condition could be treated and even prevented.  This gave birth to the use of the machines as Intermittent Positive Pressure Breathing machines, and the IPPB treatment.

The devices came with a nebulizer cup on the inspiratory circuit, and initially the medicine used was ethyl alcohol to treat patients with foaming pulmonary edema that results from heart failure.  The alcohol was nice because it soothed the bubbles, and it worked quite fast.  The IPPB was believed force the medicine deeper into the lung parychema, and thus make the medicine work better.

Soon such treatments were believed to be useful to prevent and treat postoperative atelectasis and pneumonia.  When a patient is so sore due to chest or abdominal surgery (back then it was probably usually an abdominal surgery) they tend to not want to take deep breaths due to pain.  This results in air sacks not being filled with air, and thus they collapse.  This is called atelectasis.

A non-disposable IPPB circuit with neb cup
Such hypoventilation often results in increased secretion buildup, and this causes inhaled bacteria becoming trapped in the lungs, and this results in your postoperative pneumonia.  This condition ultimately worsens the patients condition, makes treating them more complicated, and sometimes even results in respiratory failure and even death.  IPPB treatments were believed to prevent and treat this.

It was also believed IPPB treatments with Isuprel, the bronchodilator available at that time, would be useful to treat chronnic bronchitis and asthma patients.  Mucus thinners such as Alevaire and Mucomyst were also used to help patients expectorate thick secretions.  Soon these machines were used on all preoperative, postoperative and all patients with just about any respiratory disorder.  The IPPB revolution was in full stride. 

By the 1960s IPPB therapy became popular for giving aerosols to patients admitted with just about any lung ailment.  (2)  This was done despite proof it did any good. According to a 1957 article in the The American Journal of Nursing, "Nebulization Under Intermittent Positive Pressure," the following were marked as conditions treatable with this therapy: 
  1.  Pulnonary edema
  2. Atelectasis
  3. Bronchial asthma
  4. Bronchiectatsis
  5. Emphysema
  6. Pulmonary fibrosis
  7. Silicosis
  8. Impairment of respiratory function resulting from barbituate pooisoning and poliomyelitis  (3)  
Indications for such thearapy were:
  1. To overcome breathing resistence
  2. Provide more uniform alveolar aeration
  3. Distribute aerosols to terminal bronchioles where absorption takes place
  4. Relieve bronchospasm
  5. Improve bronchial drainage
  6. Provide exercise for respiratory muscles
  7. Improve pulmonary funciton (4) 
It was difficult to get some patients to coordinate breaths with the machine breaths.  And with no way of measuring tidal volumes, it was difficult to know if you were delivering the recommended 25% greater tidal volumes than the patient's normal tidal volume.  So while the machines were simple, you had to have a good teaching technique by the RT, good coordination by the patient, and good settings dialed in by the RT.

Another thing of importance to note is that at this time respiratory therapy procedures were reimbursed by insurance companies and Medicare.  There was no incentive for administrators to question the need for such therapy considering it was profitable for the hospital.  Yet this all changed in the 1970s when such therapy came "under scrutiny" when insurance and government agents questioned that the treatments did any good, especially considering they were expensive.  (5)

It was also at this time that researchers were proving by scientific evidence IPPB treatments were no more effective than using a nebulizer to deliver medicine and an insentive spirometer to encourage the patient to take in deep breaths.  Studies also showed that IPPB therapy deposit 32% less of aerosolized medicine to the lungs than a simple aerosol treatment.  Any benefits provided from the therapy were also proven to be short lived, lasting less than an hour.   (6)
Bird Mark 7

The RT textbook, "Foundations of Respiratory Care," sums up IPPB therapy for us:  "The Overuse of IPPB was eventually to become an embarassment to the profession, but in the 1950s and 1960s, IPPB devices could be seen throughout most hospitals in the United States."  By the 1990s such devices were collecting dust in the backs of respiratory therapy closets.

Yet many smaller hospitals, including the ones I've worked for, continued to abuse this therapy throughout the 1980s and 1990.  I remember doing quite a few of them in the 1990s.  Despite evidence such therapy isn't useful, one of our physicians ordered such a treatment a few weeks ago.  I actually had to have a coworker refresh my memory on the device since it had been so long since I used one.   (7)

References:
  1. Glover, 
  2. Hess, Dean R., et al, "Respiratory Care:  Principles and Practice," 2012, "Intermittent Positive Pressure Breathing," chapter 18, page 370 
  3. Stephen, Phyllis Jean, "Nebulization Under Intermittent Positive Pressure," The American Journal of Nursing," 1957, Sept., vol. 57, No. 9, pages 1158-1160
  4. Stephen, ibid
  5. Hess, Dean R., et al, "Respiratory Care:  Principles and Practice," 2012, "Intermittent Positive Pressure Breathing," chapter 18, page 370
  6. Hess, ibid, page 370
  7. Wyka, op cit

1 comment:

  1. This is a good abdominal workout if you are just starting out. CrunchesA crunch exercises is when you lift your upper body - head, shoulders, and upper back, But your lower back stays on the floor. The crunch has replaced the sit up as the most popular abdominal exercise.

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