Anatomy of a ventilator! (PART 2)

Anatomy of a ventilator (PART 2)


If you want to have a brief knowledge, go to Part I .. CLICK HERE

PATIENTS IN ACUTE RESPIRATORY FAILURE SITUATION require the management of their respiratory function with the help of a mechanical device called a “ventilator”.

The function is called to use is simple (supply the lung itself). Patients can not use the lung independently and the ventilator is a support for the management of that function. As a support, means there is no treatment. The ventilator does not cure, what it does is replace the ventilation of the lung until it improves or reset in an autonomous way.
What is important is the concept: provide a means to sustain life until the lung function is restored (if you can! RIGHT?)

Because this statement?
Damaged lungs can not be repaired because the disease has conditioned the RESPIRATION LONG process like COPD (chronic obstructive pulmonary disease or chronic) disease of certain environmental conditions that impair the function (silicosis in miners, asbestosis, etc.).. Another example is if a patient has active lung cancer.
If the function is badly damaged, probably little to offer, subject to certain mitigation measures (non-invasive ventilators) that can extend life but no longer than full indication.

Therefore there are two ways to ventilate:
1, Invasive: Mechanical Ventilation (MV): through the endotracheal tube (ETT) see figure above!
2, Noninvasive Mechanical Ventilation (NIMV): No intubation, is applied as support through a system that applies air pressure through a mask specially designed! or how a vest (which applies continuous movement across the chest).

IS USED FOR YEARS iron lung, which was a system that was moving the chest through a negative pressure which forced the patient to be his body into a chamber except for his head. These machines were common in the 50’s with the advent of the polio epidemic that affected many countries (Denmark, Sweden, Finland, USA, etc). A woman in the U.S. who spent nearly 60 years of his life in an iron lung after being diagnosed with polio as a child died after a power failure that shut down the machine that kept her breathing. See the link by clicking here as well.

AGREE, we have the most basic concepts!
now what?

WHAT IS A VENTILATOR? History teaches us many times more than today, especially because the ideas of this was from the past and not so recent!
A brief history of ventilators:

Since the development of First Pulmotor (Draeguer) in 1907 to the last and most sophisticated ventilator called “Evita” has been more than a century of technological innovation!

In its publication “Das Werden des Pulmotors” [The development of Pulmotor], Johann Heinrich Dräger (1847-1917) wrote his thoughts on how to develop a ventilator. He described a simple device to “blow cool air or oxygen in the lungs.” His “Pulmotor” 1907, was controlled by a clockwork modified.
When creating your unit chose to use a technical principle to replace the human physiology as natural as possible. With this concept, J. Heinrich Dräger was decades ahead of its time. Almost at that time the physiological concept to begin creating apparatus to ventilate these were on different paths.
As he saw it, the physiological function that needed to be replaced was a regular and constant motion of the respiratory system. For this reason chose to vent your machine based on a technical principle which led to a phase shift of inspiration and expiration during artificial ventilation. This type of ventilation is now described as a time-cycled.

The Pulmotor was designed exclusively for use in the short term. However, a number of diseases requiring long-term ventilation. For example, during the polio epidemics that followed the Second World War, many patients with respiratory paralysis should be aired in a longer period of time. This large rigid containers were developed in which the patient was ventilated place. Somewhat misleadingly, the aircraft was known as an “iron lung”. To describe its function, however, would have been more appropriate to call it a “chest of iron,” as it reflects more accurately the role of rigid packaging. Inside the container, a flexible membrane secured a constant change of pressure, so that ventilation of the lung as an artificial membrane (diaphragm).

This lesson continues another day! ….

Please keep these details of ventilation!
Santiago Herrero

Dragüer: The Evolution of Ventilation …


Herrero S. Anatomy of a ventilator (Part 2).  Journal of Pearls in Intensive Care Medicine; 2011. Vol. 1. Nº 16

J Pearls Int Care Med © 2011 ·Todos los derechos reservados. All rights reserved

Journal of Pearls in Intensive Care Medicine - Perlas en Medicina Intensiva

Herrero-Varon's MD Editors. Asturias (Gijón) and Houston (TX, USA). Languaje EN/ES 2011-2016