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How the BVM began

Strange sequences sometimes link the development of everyday things. There is an everyday device in our EDs that has such a tale to tell.

 

When I was young and the Earth was green, Artificial Respiration was a manual procedure in which one pushed and pulled on the victim’s body in the hope that one made changes in the chest’s volume that might allow air to enter. Whether Holger-Nielsen’s, Sylvester’s (or Sylvester-Brosch), Schaefer’s, Marshall-Hall, or some other iteration of technique going back 150-200 years, were mere variations with the same flaws. Small, usually insufficient, volumes of air were exchanged, and there was scant attention to patency of the airway. Yes, some lives were saved, but without consistency.

 

Expired air resuscitation from Elisha’s story in the Bible and used through the years by  midwives worked but was never popular –especially upon strangers, and was actively discouraged in the false belief that “used” air wouldn’t work. Other positive pressure methods were used such as by bellows, or pumps or gas mechanisms, but lacked efficiency and elegance but gave concern for pneumothorax.

 

In early anesthesia, patients died, if overmedicated, until control of the airway and ability to ventilate safely occurred.

 

Although Nerve Gasses (developed by German chemical interests for agricultural pesticides) were never used in WWII through mutual horror (Hitler had been temporarily blinded in WWI by Phosgene) and the strongest secret warnings of retaliation if used (only 1/3rd of the Wehrmacht was motorized, the remainder were horse-drawn; there were no effective gas masks for horses). WWII and post-war military research upon Artificial Respiration (personnel drownings, accidents) was given added impetus by the Cold War threat of gas.

 

Positive pressure ventilation worked in the OR, but was a skill not used outside unless an anesthetist was present.  Military-funded research revived expired air resuscitation which could overcome most difficulties with gas-paralyzed casualties but not that of direct facial contact when there might be residue of the gas.

 

Why is mouth to mouth so effective? Instead of pushing and pulling dying flesh, the positive pressure directly inflated the lungs. Most importantly, the rescuer could know on a continuous breath to breath basis the state of the airway and feel and see the inflation.

 

Work by Pask, Safar, Elam, Gordon,  and others in the 'forties,’fifties and through the early 'sixties established a scientific body of evidence in airway and expired air resuscitation which would help to build acceptance for mouth to mouth, initially endorsed for infants and then all ages,

 

In 1952-53, Poliomyelitis (Infantile Paralysis), then prevalent (without vaccine), became epidemic in Denmark. Heretofore, long-term ventilation was by an “iron lung” cabinet respirator that pulled on the body with negative pressure to cause air exchange. Large, bulky, and expensive, there were soon not enough to go around for the worst cases with bulbar polio and respiratory insufficiency. To care for the many patients, space and organization was taken over by the anesthetic department and systematic changes made. Thus began the concept of an intensive care unit for life support. Patients unable to breathe were intubated or had tracheostomy and were ventilated with 50% oxygen via Waters’s circuit of bag and soda-lime canister by teams of medical students and nurses. Remarkable improvements occurred.

 

At one point during the months of the epidemic, a gasoline shortage from a truckers’ strike threatened to halt the delivery of oxygen cylinders to the hospital. Mindful of this, Henning Ruben, an anesthetist at the hospital devised a rubber bag into which he inserted four bicycle spokes welded together at the ends and manipulated them with strings to an expanded self-refilling bag, then attaching a non-return gas valve he had previously invented. Working with a medical engineering firm, the bicycle spokes were supplanted by foam rubber.

 

Ruben’s “AMBU®” Air Mask Bag Unit became very successful bringing positive pressure ventilation out of ORs and ICUs into other settings. Portable, self-refilling without compressed gas yet capable of oxygen enrichment, the AMBU ® could be used in medical offices, ambulances, or outdoors..

 

So many were sold, Ruben, out of concern for the quality of training, contacted Asmund Laerdal, a Norwegian toy manufacturer and they developed a training mannequin which became Resusci-Anne.

 

There is a military AMBU® version with filter canister. Gas masks for personnel have adapter tubes to connect with other gas masks for expired air resuscitation.

 

The AMBU® trademark has been so commonly used that it has become genericized as has Kleenex of Band-Aid.

 

The self-inflating manual resuscitator has become so widespread that the use of flow-inflating bags is now a relatively arcane skill concentrated in OR, PACU, Newborn ICU, and ICUs.

 

Now when you see or use an “ambu” bag, or are recertified with a mannequin, or send a patient to an intensive care unit, you will, as Paul Harvey used to say, “know the rest of the story,”

 

Sincerely,

 

Tom Trimble, RN CEN

All opinions are solely those of the author.

 

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