Wednesday, April 15, 2020


POLIO AND THE BIRTH OF RESPIRATORS



     Headlines during the Coronavirus epidemic have emphasized a critical shortage of respirators. The shortage is reminiscent of earlier epidemics associated with inqdequate respirator supplies: polio epidemics.

     Polio spreads fear partly because patients with upper body paralysis are unable to breathe, signaling a death sentence before the invention of respirators. The earliest devices to aid breathing were tilt tables, allowing the abdominal contents to push up against the diaphragm when tilted head-down and pull down when more erect. They had limited success. In 1928, Phillip Drinker, holder of a degree in chemical engineering and an instructor on ventilation and illumination at Harvard’s new School of Public Health, was consulted by Boston’s Children’s Hospital to help young polio victims, unable to breathe. Drinker had already developed a respirator for industrial cases of gas poisoning. With the help of Louis Agassiz Shaw, Drinker placed a cyanotic eight-year-old girl into the new device - an “iron lung” – a large metal tank, closed at the neck, that generated negative pressure to expand the lungs in a rhythmic fashion. The girl’s color pinked up quickly as the device took over her breathing. The “Drinker respirator” came into common use for polio patients. It was soon modified by John Emerson, a gifted man engaged in developing research apparatus for Boston-area medical schools. The Emerson respirator was more efficient, quieter, and cheaper, and was soon adopted as a standard. Drinker sued Emerson over patent rights, but eventually he lost both the suit and his patent rights. Tracheostomy as a way to control secretions while in the iron lung also was employed.
Polio Ward at Rancho Los Amigos National Rehabilitation Center, 1953. (Wikipedia)
     In 1952, polio’s devastation was unprecedented, the number of afflicted rising to almost 58,000 nationwide. Schools, churches, pools, and other public gathering spots were shut down and children kept indoors. In hospitals, Emerson respirators worked overtime, and thousands were in use. In far-away Denmark, the virus was equally relentless, with 5,722 cases throughout the country. In Copenhagen, one hospital, the Blegdams Hospital, with 500 beds, was assigned to handle polio patients. But the hospital, still suffering economically from the war, had only one “iron lung”, and six smaller, weaker versions, covering only the chest. Polio admissions ran as high as 30 to 50 a day, with 6 to 12 a day needing respiratory help. Doctors agonized over having to decide who got a respirator and who did not. An anesthetist, Björn Ibsen, was called to help, and help he did. 

     Ibsen, while a medical student in Copenhagen, had spent a rotation administering anesthesia at a provincial hospital in Jutland, using an ether mask. He had never intubated a patient and anesthesia was not a specialty in Denmark. To obtain further training he accepted a position at Massachusetts General Hospital as an anesthetist,
Henry Beecher (Wikipedia)
working under Henry K. Beecher. When he arrived in 1949, open drop ether was the method used and medical students had to induce at least 10 patients before graduating. A year later Ibsen was back in Copenhagen, working as a freelance anesthesiologist.

     When Ibsen arrived at the beleaguered Blegdams Hospital, the few tank respirators available functioned poorly. Twenty-seven out of thirty-one respirator cases died in spite of tracheostomies done to control secretions. Further, knowledge of blood gases was just emerging and not widespread among clinicians.  Having just read an article on the buildup of carbon dioxide in the body in such cases, Ibsen suspected this was part of the problem.

     A 12-year-old girl, turning blue and struggling to breathe, was Ibsen’s first patient. He showed quickly that CO2 narcosis developed at times of diminished breathing (by measuring the expired CO2), even with proper oxygenation. He relieved her distress
Björn Ibsen (Wikipedia)
with a tracheostomy and a bag respirator. Tracheostomy and artificial breathing with a bag respirator became routine as a supplement to tank respirators or as the sole breathing assistance. Medical students were called in to hand operate the respirator bags, working in 6-hour shifts around the clock. It was emotionally exhausting work, breathing for a child who was paralyzed and unable to speak. Standbys were also needed in case a student was sick or cancelled. (For an image of this see:
https://www.nature.com/articles/d41586-020-01019-y?utm_source=Nature+Briefing&utm_campaign=64fb5afbff-briefing-dy-20200406&utm_medium=email&utm_term=0_c9dfd39373-64fb5afbff-44774997 ).

     Anxiety about contracting polio from the work and worry about finishing the medical curriculum led many students to drop out of the program after a few weeks. Dental students were next recruited. Eventually about 1,500 students put in 165,000 hours hand-ventilating. Bang & Olufsen designed and made mechanical respirators to relieve the strain, though the firm later concentrated on audio equipment.

     Many patients who were maintained on continuous bag respiration recovered to breathe on their own. Ibsen’s first polio patient, the 12-year-old girl, lived to the age of 31, when she died of pneumonia and diabetes.

     Ibsen also pioneered in the treatment of tetanus, using curare to paralyze the respiratory muscles while breathing for the patient, a treatment he had been advised against while in Boston. Later he was asked to consult on fluid replacement postoperatively in another hospital. He turned that hospital’s recovery room into the precursor of an ICU, said by some to be the world’s first, and later wrote a book on shock.

     It is an old truism that war spawns innovations in medical treatment. The same might be said of epidemics. The hand-operated respirators of the Blegdams Hospital, later mechanized, replaced iron lungs. And the successful Salk vaccine entered its first trials the year after the 1952 epidemic.


SOURCES:
Wackers, G L Constructivist Medicine. 1994; Thesis, University of Maastricht.
Lassen, H C A. “A Preliminary Report on the 1952 Epidemic of Poliomyelitis in Copenhagen.” 1953; Lancet Jan 3, pp 37-41.
West, J B. “The Physiologic Challenges of the 1952 Copenhagen Poliomyelitis Epidemic and a Renaissance in Clinical Respiratory Physiology.” 2005; J Appl Physiol 99(2): 424-32.
Shaw, L A and Drinker, P. “An Apparatus for the Prolonged Administration of Artificial Respiration: II. A Design for Small Children and Infants with an Appliance for the Administration of Oxygen and Carbon Dioxide.” 1929; J CVlin Invest 8(1): 33-46.
Phillip Drinker, obituary. 1973; Ann Occup. Hyg. 16: 93-4.
Berthelsen, P G and Cronqvist, M. “The First Intensive Care Unit in the World”.   2003; Acta Anaesthesiol Scand 47: 1190-5.
Senelar, L R. The Danish Anaesthesiologist Björn Ibsen: A Pioneer of Long-term Ventilation on the Upper Airways. 2009; Thesis, Johann Wolfgang Goethe University, Frankfurt am Main.
Lassen, Bjorneboe, Ibsen, and Neukirch. “Treatment of Tetanus with Curarisation, General Aneasthesia, and Intratracheal Positive-Pressure Ventilation.” 1954; Lancet Nov 20, pp 1040-4.
 Oshinsky, D. Polio, An American Story. 2005; Oxford Univ Press.

No comments:

Post a Comment

Comments are welcome. Especially new knowledge, insights, and sources of further information.