1907: The first mechanical ventilator: The Pulmotor

Medics using Pulmotor to save a lifeIn 1907

Concerned for the people who were becoming asphyxiated and dying due to gas exposure in mines, Heinrich Drager of Germany (1898-1986) set out to invent a machine that would help keep these people alive until the gas wore off.  In 1907 he finished his work, and received a patent for what he referred to as the Pulmonator.  (1, page 8, 12)

The device was connected to an oxygen tank and was then powered by oxygen pressure and alternated positive and negative pressure to provide breaths.  It was the first time cycled ventilator*, in that it gave a breath for a designated amount of time, guaranteeing the patient would get an equal breath with each inspiration.  (1, pages 12,14)

This is the title and pictures of an article about how the Pulmotor
"pulled back through the doors of death" 400 persons in Baltimore
"during the past six years."  Left:  A police officer in a "special vehicle,"
ready "for a dash to save a life."  Right: "Showing how the Pulmotor is
used to save a life."  The article notes: "In a large number of cases,
 a small machine, one that could be lugged around by a grown man,
 was responsible for this almost miraculous feat in life-saving. 
It was a pulmotor, the property of the Consolidated Gas, Electric Light 
and Power Company." Published in Gas Age, circa 1922. (7, page 258)

A later model was designed by Bernard Drager (son of Heinrich) and Hans Schroder that was pressure cycled, in that it gave a breath until a designated pressure was met, guaranteeing the patient's lungs would not be over-inflated. This later model turned out to be much more efficient for clinical use because it (at least in principle) was supposed to prevent over-inflation of the lungs, and was easier to use by clinicians. (1, page 18)

The operator would also have to have knowledge of pressure controls and of pressurized oxygen. He would set up the machine, turn on the tank, and place a rubber mask over the mouth and nose of the victim.  In order to provide adequate ventilation, he would have to hold the mask tightly over the patient's face.  As you might expect, this would have been daunting work.

"No one can foretell the need of a Pulmotor. To put too much dependence
 on being able to borrow a Pulmotor is dangerous. The owner may be using it,
or someone else may have it. To depend entirely on manual methods,
or on devices of questionable merit is leaving yourself open
 to your own reproaches  and to those of others. Pulmotors are the standard
 resuscitation apparatus throughout the world. In their ten years of service to humanity
 not one case can be found where injury resulted from their use.
 On the contrary, they have saved countless lives, many after all other means,
 both mechanical and manual, had failed." (10, page 156)

He'd also have to have an assistant watch the oxygen tank to make sure it was full and change it when it was close to becoming empty.  Yet since there were no efficient regulators at this time, the operators would have to use a formula to determine how long a tank would work, or they would simply guess.  

The machine worked similar to fireside bellows  in that it forced oxygen into the lungs, and then it sucked air back out.  (2)  It was mass produced by Draegerwerks, a company in Ludwig, Germany, and advertised heavily in various magazines marketed to gas companies, such as Gas Age.  

A 1922 article in Gas Age shows a special police automobile specially prepared with a Pulmotor owned by the Consolidated Gas, Electric Light and Power Company.  The product was originally purchased   in 1913 for "employees of the gas company overcome by gas in trenches or underground passages. Then some one outside the company was overcome by gas and the pulmotor crew was asked to lend its aid.  That was the beginning, and... requests for use of the life saving apparatus 'just grew' until now the private calls run up into the hundreds each year." (7, page 257)

sent rushing in a special automobile through the streets of the city day or night at any minute to try and add another name to the list of those whose lives it has saved."  (7, page 257)

"Your Fire Department Needs it... Our Health Department Needs it:
Do you know... that the pulmotor has saved lives of those
who have been pronounced dead by reputable physicians?"
chimes an advertisement in The American City (circa 1915)
for The Draeger Oygen Apparatus, a.k.a. the pulmotor.
This and similar ads could be seen in various magazines marketed
to cities around the U.S. and Europe.  (11)

So, as you can see, the product, or apparatus, was put to good use, and was soon donated to the Baltimore Police Department.  Volunteers, in their "special automobile" could be "

There was but one pulmotor for all the three-quarter of a million inhabitants of Baltimore, (7, page 257) and this was pretty much how it was in most cities with the privilege of having such an apparatus.  Since there were few of the products available, it often took a while getting to the scene.  In such cases, as noted in the Gas Age article, "time, and not the machine, may have been responsible for the death... in the 187 deaths recorded by the company, nearly all were what are called hopeless cases.  In other words, the pulmotor was called after death and probably ensued for hours, principally in cases of suicide by inhaling gas, and drownings."  (7, page 257)

Typical mask used for pulmotor and similar devices.  It was designed
by Dr. John Haldane to be worn by people exposed to gas during WWI.
The Haldane Mask in this picture was was a redesigned model so that
it could be used "in either foul or fresh air."  Oxygen came from the tank
through the oxygen inlet (A).  A one way valve in the jount box (B)
opened on inspiration allowing air (or oxygen) to come from the tank,
and closed on expiration to allow expiration into the atmosphere.
 (13, part III, page 25)

The article describes the typical rescue attempt for the crew:  (7, pages 257-258) 

There is little reward for the small band of 20 men who go out with the pulmotor on calls.  A telephone message is received from the police that "John Jones"  at a street in the farthest end of the town has been "found in a gas filled room." The lifesaving machine rushes out and John is revived. In a newspaper account of the affair it may be casually mentioned that "the pulmotor was called," but that is all. Nothing is said of how long the crew worked to resuscitate John. Perhaps it took four hours. Four or five tanks of oxygen may have been used. But it is all in a day's work for the pulmotor crew. To report another person as "saved" is all the reward they ask... Most calls the pulmotor answers are to revive persons who attempt suicide by inhaling gas. Answering these is not a necessary part of the work of the gas company, as its responsibility ends at the gas meter, but it responds just the same. Others are overcome by an accidentally turned on gas cock, and again sometimes the pulmotor is called out to revive whole families overcome by coal gas or some one overcome while tinkering with his automobile engine... Then there are the calls from hospitals when some one has failed to revive after an operation. The machine is also wanted at times for cases of heart trouble, at child birth, in attacks of pneumonia and other ills, and one case is on record where a few years back the pulmotor kept a baby with diphtheria alive for several days... Most reports of the operating of the pulmotor, telling of suicides or unsuccessful attempts to end one's life, are gruesome. But every now and then there is a report that brings a smile.(7, page 257)

The top two pictures show a rescue station at a mining company.
"Among the equipment of the station is a "Dr. Bratt" resusitator.
 This is a device for inducing artificial respiration and administering oxygen. 
It consists of a flash of oxygen connected by the tube with a mask
 for the mouth and nostrils. By moving a handle to and fro the lungs
of an unconscious person may be inflated and deflated as in natural breathing.
 The deviceis of special value for reviving men who have been "gassed,"
 particularly those suffering from the carbon monoxide poisoning"
The lower left shows the apparatus, and the lower right shows it in use.
A Draeger apparatus (the pulmotor) was also among the equipment.
Part of the rescue station is set up as an emergency hospital.
(14, page 594-596)  Click link for better view of pictures.

I find it interesting that this mechanical ventilator was at times rushed to the hospital.  Little did they know that the machine they were using was just the beginning, and that within the next 50 years mechanical ventilators would be common in hospitals, although used to save lives just the same.

So most pulmotors were advertised and purchased by places where people were at high risk, such gas companies, mining companies, and electric companies.  As success stories were shared by the media, such companies donated the use of their pulmotor to the community.  As calls came, the team rushed to treat victims of electrocutions, near drownings, medicine overdoses, smoke inhalations, gas inhalations, drug overdoses, poliomyelitis, etc.

Each city had their own system set up, as some gas, electric and mining companies created their own teams to rush the pulmotor to the victim, while other cities stored the pulmotor in emergency vehicles, such as police cruisers, or stored them in the hospital setting.

Another example of the pulmotor team helping the community can be seen in a 1912 editorial in the South Carolina Practitioner:

The Los Angeles Police Commission has accepted the offer of the Los Angeles Gas and Electric Corporation for the free use of the Pulmonator.  The machine will be kept at the receiving hospital.  A pulmonator was recently successfully used in San Diego on a case of morphine poisoning that had remained unconscious overnight.  (4, page 412)

Yet another example can be seen in a 1913 issue of Electric Review:  (9, page 69)

"In order to make available over the largest possible territory the use of its free pulmotor service, The Toronto Electric Light Company, Limited, has secured the co-operation of Captain Ward, in command of the Government Life-saving Station at Ward's Island, and Mait Aykroyd, the well-known lifesaver at the foot of York Street... "Many persons apparently drowned have been revived by the pulmotor when all other means of resuscitation have failed. A large number of the company's men has been trained in the use of the pulmotor by The Toronto Electric Light Company, Limited and two or more are always on duty at the company's station at the foot of Scott Street. The telephone call for Scott Street is Adelaide 404...  "The police and the public are urged to call for the pulmotor immediately and not try to do without it. The pulmotor is perfectly capable of resuscitating drowned persons if life is not extinct, but it cannot restore life. The quicker it is put to work, the better is the chance of saving life... "The rapidity with which the pulmotor may be obtained was illustrated only the other day. A drowning accident occurred at Centre Island and some one telephoned to Captain Ward. He at once started for the Scott Street Station of The Toronto Electric Light Company Limited, in his fast motorboat, while one of his crew at the life-saving station telephoned to Scott Street that he was on the way and to have the pulmotor with its crew ready to meet him. In three minutes Captain Ward was at the Scott Street dock, had picked up the pulmotor and the company's men, and was on his way to Center Island, which was reached in nine minutes... "It has also "been arranged to send the pulmotor in a automobile to meet Captain Ward where time can be saved in so doing... "The public and police are urged to report drownings immediately to Captain Ward or Mait Aykroyd. They will give the requisite orders to the pulmotor crew at Scott Street and assume command of the situation in person". (9, page 69)

In the event that a person truly stopped breathing yet was still technically alive, the machines must have been a Godsend, as they would have provided an opportunity for bystanders to help keep someone alive. This resulted in an evident media hype, where rescue attempts with the Pulmotor were reported by the Press. One such example was provided by the January 13, 1913, issue of the Pipeline and Gas Journal:

"The first (Consolidated Gas Company) now has four of these devices in use, and the first practical trial of its was made November 7, 1912, when a call for the crew with the apparatus came in from the Flower Hospital, to which institution a woman had been carried.  She was suffering from gas asphyxiation... The emergency crew... responded to the call.  The patient was seemingly not breathing and the pulse could not even be detected.  (The foreman) attempted to show the doctors how to operate the apparatus, but they were slow to comprehend the actual method, wherupon (the foreman) assumed the task himself.  In about 10 mintues the patient was restored to consciousness." (6, page 34)

A report published in 1922 by the United States Bureau of Mines, "Report of the Committee on Resuscitation from Mine Gases," suggested that despite various success stories using the machine, the benefits of using it may have been over-hyped by Draeger and the various gas, mining and electric companies who owned one as public relations stunts. The media just sort of naively played along.  (8 page?)

For instance, the Bureau report listed some of the few actual success and failure stories written about in the various medical literature (such as the Journal of the American Medical Association), and said  that "in none of these instances is there a careful account of the action of the instrument. And only when an observer publishes his experience in detail, gathered in a number of cases, can we judge whether his observations are unbiased, his statements truthful, and his conclusions justifiable." (emphasis added)

The report continued:  

By the kindness of the head physician to the Edison Co., of New York, opportunity was obtained to examine 21 records of gas poisoning in which the pulmotor was reported as having been used with success. Most of the reports were written by chauffeurs and only a few by physicians. In most of the reports no distinction was made between unconsciousness and absence of respiration; and, as already explained, the sensitiveness of the higher centers of the brain to lack of oxygen may result in unconsciousness, while the centers governing respiration still continue active. Indeed, breathing may persist for some time after the degree of asphyxia is such that death is almost certain to ensue. Only in a few of these 21 cases was there reason to assume that breathing might have been suspended. Letters sent to the various physicians mentioned brought either an unsatisfactory answer or none at all. Of two additional cases that were reported, in one no machine was used, and in the other, a case of opium poisoning, intratracheal insufflation was employed and erroneously regarded as identical with the action of the pulmotor." (8, page 20)

The report notes that in many of the reported success stories, there was more evidence that something other than the pulmotor revived the victum, such as:  (8, page 21)

• Oxygen provided by the device (8, page 21, 23)
• Hypodermic injection (of some unknown medicine) 
• Manual respiration (such as prone position or the Sylvester method 
• Manual respiration coupled with oxygen 
• Unknown what was done because nothing was written, other than that the pulmotor was at the scene  
• Breathing not absent, and pulmotor not even indicated (8, page 21-23))

There were cases where the victim was pulled from the scene, and nothing was written about what happened  in the interim prior to the pulmotor arriving on the scene: 

In the eighth case (Burgess) the pulmotor was first applied 30 minutes after the victim had been removed from the gas atmosphere. No statement is made as to what was done for him in the interim. In the ninth case (Enzian) Dr. McGuire, of Wilkes-Barre, " endeavored for two hours to revive her by artificial respiration. Failing in this, a pulmotor was brought a distance of 8 miles, and under the manipulation of Mr. G. T. Holdaman the patient was revived in two or three hours.'' .Cases 8 and 9, in which the victims lived a long time before the application of the pulmotor (half an hour and two hours), do not present convincing evidence. In case 7 the pulmotor did at least as much as the Silvester method, but that does not show that it did more. These reports are in no manner satisfactory documents for demonstrating the superiority of the pulmotor as a device for artificial respiration.  (8, page 22)

In one case described by the bureau, "manual artificial respiration combined with oxygen continued the respiratory function for much longer than the critical period, and the pulmotor was not necessary." (8, page 21)

In other words, according the the Bureau, in most cases there was no evidence the pulmotor provided any benefit whatsoever to the patient.  The only people who benefited were those who profited from sales of the machine, and those who profited by the positive public relations from the service provided. (8, page 23)

Or, as stated in the report: 

"In regard to such reports it is scarcely necessary to point out that, because of the financial interests involved, a considerable degree of caution should be exercised in estimating their value. A high official of one of the important electric companies in the country testified to a member of the committee, "We have to buy these machines, even if they are no good, as an evidence of our good faith and our desire to do everything possible to safeguard the public and employees."
  " (8, page 23)

This suspicion may have been hinted at in an editor's note attached to the above mentioned article from Gas age: (7, page 257)

Hint to gas men.  Have you a pulmotor at the plant?  Offer it to the police department and by and by some newspaper reporter will write it up. (7, page 257)

It was also hinted at in the article noted above from Electric Review, which began with this:

In line with its policy of establishing friendly relations with the public, as well as to perform a worthy public service, the Toronto Electric Light Company has announced through local papers that it desires citizens of Toronto to call for the company's pulmotor in drowning accidents. (9, page 69)

We must note here, however, that there were obvious success stories, and even the Bureau noted this: (8, page 23)

Although the cases reported above do not furnish convincing proof of the necessity or the exceptional value of the mechanism of the pulmotor, that mechanism is probably capable of creditable performances, and in some instances may have favored the restoration of normal breathing. (8, page 23)

The medical profession is historically known to regard new products with suspicion.  It is not uncommon for something new, like the pulmotor, to be criticised, and in some cases criticised heavily.  Yet in the case of the pulmotor, I might have to presume the criticism was probably justified. 

Surely some criticism was simply slathered about by stubborn old professors and physicians who were stuck in their ways and resistant to any change.  In other cases the evidence might have been used to prop up another product, such as the Dinker Respirator (the first marketable iron lung, or negative pressure ventilator)

In 1929, Drinker, along with Charles F. McKhann, published in the Journal of the American Medical Association, "The Use of a New Apparatus for the Prolonged Administration of Artificial Respiration: A Fatal Case of Poliomyelitis," evidence that manual resuscitators did not provide the necessary oxygen needed to benefit patients, and mechanical resuscitators like the pulmotor** forced too much air into the lungs too fast, increasing the risk  of doing more harm than good.  (5)(12)

Dinker and McKhann were, however, right.

There were three basic concerns regarding the pulmotor, all of which were the subject of various reports.

1.  Too much air forced into the lungs too fast may cause over-inflation.  Concerns regarding over-inflation of the lungs began in 1829 when Leroy d'Etiolles used fireside bellows to breathe for dogs, and he later noted that such efforts were harmful to dogs, sometimes killing them.   Studies by S.J. Meltzer and others confirmed the concerns of d'Etiolles by showing the lungs of animals inflated with the pulmotor for extended periods of time "presented an uneven appearance -- small collapsed areas alternating with emphysematous ones."  (15, page 2, 5)  Such studies showed that the Pulmotor had no way of sensing if it was giving too much or too little air.  In other words, it did not compensate for airway obstruction that may occur in lungs with diseases such as asthma, bronchitis, etc. Likewise, if the patient was awake this would result in uncomfortable breathing.  Adjustments were made to the machine over time to accommodate for this problem, such as a switch that allowed the operator to end inspiration. The switch from time-cycled to pressure cycled was also an effort to remedy this problem.  Modern clinicians continue to be concerned about over-inflation.  (5)(1, page 24)(12)(13)

2.  Negative pressure may cause atelectasis.  The negative pressure (suction) intended to suck air out of the lungs was thought to cause collapsed lungs, or atelectasis.  This was assumed to be a problem due to the results of an autopsy that found atelectasis in the lungs of a patient the Pulmotor was used on.  ()  This concern is no longer considered relevant. (1, page 24)(13)

3.  Delay in set-up time may harm cause harm to patient.  In many of the stories reported by the media, there were delays as long as an hour, or even more.  This may have been due to delays in realizing there was a problem, and also due to delays in rushing to get the machine and to set it up.  One can only imagine the stress of the situation that may have resulted in those unfamiliar with the equipment fumbling to set it up, and then to keep it running.  Delayed efforts to set up the device may result in patient asphyxia. (5)

4.  Clinician exhaustion may cause harm to patient. The mask had to be held on to the patient's face, and it often had to be held firmly in order to provide adequate breaths.  This in itself would have been exhausting.  Yet the clinicians would also have suffered from mental fatigue and stress in order to make sure their equipment was running correctly, and that there was still oxygen in the tank.  (5)

5.  Air is "liable to be driven into the stomach, but this can be prevented by pressure on the trachea." (8, page)  This was just one more thing operators of the device had to be aware of.

6.  Not enough oxygen was delivered to the patient:  According to studies performed by John Haldane and Yandell Henderson, the Pulmotor delivered only 26.75% oxygen to the patient, as compared with the 21% oxygen contained in room air. This would not be sufficient supplemental oxygen to provide much benefit to the patient. (16, page 5)

A report originally published in 1920 by the Great Britain Department of Scientific and Industrial Advisory council noted the following:

We have tried all these devices (mechanical respirators*); in addition to the drawbacks of complexity, bulk and weight, those producing forced breathing are physiologically unsound, and their use is not free from serious danger. Forcibly to blow oxygen into lungs which are already distended to the full, or to apply strong suction to lungs already deflated, is to risk permanent injury to those organs. Again, though one tries to reduce the possibility by drawing the tongue well forward, there is a chance of these apparatus functioning upon the stomach instead of on the lungs. We therefore consider that all forms of forced-breathing revivers should be abandoned, and that the simple form, in conjunction with artificial respiration, should be employed solely.  (13, part III, page 25)

Regardless of the concerns, by 1908 there were 3,000 Pulmotors in use at various locations around the United States and Europe.  By 1918 that number doubled to 6,000, and by 1956 there were 12,000 Pulmotors in use. (1, page 24)  By this time, however, the machine had been improved upon many times to make up for past flaws.

While the Pulmotor may not have been the ideal ventilator, it was a great idea that was put to good use.  The product was ultimately phased out with the invention of the bag mask valve (AMBU-bag) and better mechanical ventilators in the 1950s.

*  Time cycled means that inspiration ends when flow from the mechanical ventilator ends and expiration begins.

**Note:  There are other devices that were similar to the pulmotor and were used as "revivers at mine rescue stations, such as the Bratt's Apparatus and the Lungmotor.  However, these devices were hand operated as opposed to mechanically operated.  There were also simpler methods, mostly which consisted of "an oxygen cylinder, a reducing valve, a throttle, a distensible bag and a face mask connected to the bag by a length of flexible tubing.  (13, part III, page 25) The notable criticism listed above was also aimed at these products, of which, when used to provide positive pressure breaths, probably forced in too much air too fast.  Because they were hand operated, they probably resulted in worker fatigue more rapidly than the pulmotor.

References:

1. Bahns, Ernest, "It began with the Pulmotor:  100 years of Artificial Ventilation," 2007, Germany, Drager Medical AG and CO. KG
2. "Medical Discoveries," discoveriesinmedicine.com, http://www.discoveriesinmedicine.com/Hu-Mor/Iron-Lung-and-Other-Respirators.html, accessed, 7/29/13
3. "Draeger Pulmotor," The Wood Library Museum,   http://woodlibrarymuseum.org/museum/item/96/draeger-pulmotor, accessed February 26, 2012
4. "Medical Discoveries," discoveriesinmedicine.com, http://www.discoveriesinmedicine.com/Hu-Mor/Iron-Lung-and-Other-Respirators.html, accessed, 7/29/13
5. "Iron Lung: 1929 Dinker Respirator," University of Virginia Historical Collections at the Claude Moore Health Sciences Library,"  http://historical.hsl.virginia.edu/ironlung/pg4.cfm, accessed February 26, 2012
6. "Items of interest from various localities," Pipeline and gas journal, Jan. 13, 1913, page 34  
7. "Pulmotor advertises gas company," Gas Age, volume 29, 1922, New York, Robbins Publishing Company Inc. 
8. Cannon, Walter Bradford, George Washington Crile, Joseph Erlanger, Yandell Henderson, "Report of the Committee on Resuscitation from Mine Gases," Technical paper number 77, Department of Interior, Bureau of Mines, Joseph A. Holmes, Director, 1914, Washington, Government Printing Office
9. Worthington, George, editor "Commercial Practice: Management, Rates, New Business," Electric Review, Volume 63, July 5 to December 7,1913, Chicago, Electric Review Publishing Company
10. Parsons, Floyd W, editor, "The Pulmotor," Advertisement, Coal Age, Volume 11, number 2, January 13, 1917, New York, Hill Publishing Company, page 156
11. Pulmotor advertisement appeared in The American City, Volume 12, January to June, 1915, New York, The Civic Press.  Similar ads by Draeger appeared in various other similar magazines.  
12. Drinker, Phillip, Charles F. McKhann, "The use of a new apparatus for the prolonged administration of artificial respiration," 1986, Journal of the American Medical Association, issue 255, number 11, pages 1473-1475
13. "Report: Great Britain Department of Scientific and Industrial Advisory Council: Second Report of the Mine Rescue Apparatus Research Committee," 1920 (reprinted 1921), London, His Majesty's Stationary Office, part II, Miscellaneous, page 25
14. Gray, F. W., "The mining operations of the Dominion Coal Company," The Canadian Mining Journal, November 15, 1908, Volume XXIX, Number 22, Toronto; Published in the "Index: Canadian Mining Journal, volume 29, January 1, 1908, to December 31, 1908, The Mines Publishing Company Limited, Toronto, Ontario. Click the links for a better view of pictures. 
15. Meltzer, S. J., "History and analysis of the methods of resuscitation," Medical Record: A Weekly Journal of Medicine and Surgery, July 7, 1917, Volume 92, Number 1, New York; Meltser
16. Meltzer, S. J., "History and analysis of the methods of resuscitation," Medical Record: A Weekly Journal of Medicine and Surgery, July 7, 1917, Volume 92, Number 1, New York; Meltser references the following: Yandell Henderson: Technical Paper 77, Bureau of Mines, Washington, D.C., Government Printing Office, 1914, page 12