quarta-feira, 29 de fevereiro de 2012

A preliminary report on the 1952 poliomyelitis epidemic in Copenhagen with special reference to the treatment of acute respiratory insufficiency.


A preliminary report on the 1952 poliomyelitis epidemic in Copenhagen with special reference to the treatment of acute respiratory insufficiency.

Author: Lassen HCA
Lancet 1953; 1: 37–41

Summary
This paper describes the extraordinary events at Blegdan Hospital in Copenhagen during
the poliomyelitis epidemic of 1952.

Between 24 July and 3 December 1952, 2722 patients were admitted to the institution
with acute poliomyelitis. Of these, 866 had paralysis and 316 had some degree of
respiratory insufficiency. In 4 months, the hospital faced three times as many patients
with respiratory insufficiency as it had in the previous 10 years. At any one time, up to 70
patients required ventilatory support, and Dr Lassen candidly admits that the hospital was
in ‘a state of war’.

At the start of the battle, negative pressure devices were the standard tools for ventilatory
support. However, the hospital possessed only one tank and six cuirass respirators.
Furthermore, results using this equipment in the sporadic cases before the epidemic were
poor (mortality 80%), and had not been improved by the introduction of tracheostomy
in 1948.

The equipment and techniques available for patients with respiratory failure at the outbreak
of the epidemic were inadequate, and this was reflected in mortality of 87% during
the first month. At this point, after consultation with anesthetist Dr Bjorn Ibsen, treatment
for these cases was changed to include:

1. Early tracheostomy just below the larynx in those unable to maintain an unobstructed
airway.
2. Suctioning and bronchoscopy via the tracheostomy.
3. Postural drainage.
4. Positive pressure ventilation via a cuffed rubber tube inserted into the tracheostomy
(see Figure1-2).

Fig. 1-1. Typical equipment available for respiratory failure in 1952: an iron lung (left) and a Kifa cuirass (right). (Image of child in iron lung reproduced courtesy of the WHO Global Polio Eradication Initiative. Image of adult reproduced from Lassen HCA (ed). Management of Life-threatening Poliomyelitis. Edinburgh: E & S Livingstone, 1956.)



Fig. 1-2. A polio patient with respiratory insufficiency being ventilated manually via a tracheostomy (left).
A schematic diagram of the ventilation circuit is shown. (Figures reproduced from Lassen HCA (ed). Management of Life-threatening Poliomyelitis. Edinburgh: E & S Livingstone, 1956.)


Two hundred patients required continuous or intermittent ventilation, some over 3
months. Insufflation was carried out manually, by medical students working in shifts.

The change in mortality for cases of respiratory insufficiency following the introduction
of these techniques was striking, falling from 87% to 40%.


Related references
1. Drinker P, Shaw LA. An apparatus for the prolonged administration of artificial respiration.
A design for adults and children. J Clin Invest 1929; 7: 229–247.
2. Lassen HCA (ed). Management of Life-threatening Poliomyelitis. Edinburgh: E & S
Livingstone, 1956.


Key message
Mortality from acute respiratory insufficiency (due to poliomyelitis) can be reduced by
tracheostomy, suctioning, postural drainage, and positive pressure ventilation.

Why it’s important
This experience heralded the widespread use of positive pressure ventilation for acute
respiratory failure, and may be considered the beginning of the modern era of mechanical
ventilation, and indeed the origin of the specialty of intensive care medicine.

Strengths
This paper is both a landmark in medical science and a fascinating historical document.

Relevance
From the experiences gained in positive pressure ventilation, Lassen highlighted a number
of problems that would be investigated for decades. These included the deleterious effect
of prolonged insufflation on cardiac output, problems with weaning, and the benefits of
timing insufflation to coincide with spontaneous respiratory effort.