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Topic Name: Leveraging learning for artificial respiration
Category: Mechanical
Research persons: Dr. Chi-Sang Poon's
Location: 77 massachusetts avenue, cambridge, ma 02139-4307, United States
Details
Rresearchers have found that the body's innate ability to adapt to recurring
stimuli could be leveraged to design more effective and less costly artificial
respirators. The new approach could minimize the need for the induced sedation
or paralysis currently necessary for some patients on mechanical ventilation.
Nonassociative learning, or our innate ability to adapt to recurring stimuli,
is the focus of work to be described in the September 12 issue of PLoS ONE, the
online, open-access journal from the Public Library of Science.
Specifically, Chi-Sang Poon, a research scientist at the Harvard-MIT Division
of Health Sciences and Technology (HST), and colleagues examined rats under
mechanical ventilation to see how they applied different forms of nonassociative
learning to adapt to the rhythm imposed by the respirator.
Existing respirators do not consider the adaptive nature of breathing in
their design. Some ignore the patient's natural rhythm and pump air in and out
of the lungs on set intervals. As a result, doctors often must sedate or
paralyze patients to prevent them from fighting an unfamiliar rhythm. Other
respirator designs rely entirely on the patient to trigger the airflow. These
systems, however, are costly and tend to be unreliable for weak patients such as
newborns or those in critical care.
The MIT research suggests, however, that if a doctor takes the patient's
natural breathing rhythm into account and sets the ventilator's rhythm in that
same range, the patient will adapt and synchronize with the ventilator. This new
approach could minimize the need for induced sedation or paralysis.
"We have intrinsic nonassociative learning capabilities, called habituation
and desensitization, that [can] make up for changes in the spontaneous rhythm
due to artificial lung inflation," says Poon.
In tests of rats under artificial respiration, Poon found that, if using a
suitable rhythm, rats adapted to the mechanical ventilation. He also found that
this learning capability enabled mice to adapt to an artificial rhythm even when
the mechanical respirators applied constant air pressure. The rats effectively
"tuned out" this extra pressure, filtering it out as background noise. When Poon
disabled the neural pathways involved in nonassociative learning, the rats'
ability to adapt was either eliminated or compromised.
Though nonassociative learning is familiar and commonly applied to smelling
roses and adjusting to sunlight after emerging from a dark movie theater, it is
not usually applied in a clinical environment. Because of their focus on
stabilizing patients, clinicians often discount the power of learning. "Many
ventilators are designed as if the patient were never in the equation," says
Poon. "But it turns out, our vital functions can learn to adapt in order to
survive."
Poon's coauthors of the PLoS ONE paper are Shawna M. MacDonald of MIT's
Department of Mechanical Engineering and Gang Song, an HST research scientist.
This work was supported by the National Heart, Lung and Blood Institute of
the National Institutes of Health.
About The Researcher
PLoS ONE, Dr.
Chi-Sang Poon's
Chi-Sang Poon Laboratory - Harvard-MIT Division of Health Sciences & Technology
Artificial respiration
Artificial respiration is the act of simulating respiration, which provides
for the overall exchange of gases in the body by pulmonary ventilation, external
respiration and internal respiration.[1] This means providing air for a person
who is not breathing or is not making sufficient respiratory effort on their
own[2] (although it must be used on a patient with a beating heart or as part of
cardiopulmonary resuscitation in order to achieve the internal respiration).
Pulmonary ventilation (and hence external respiration) is achieved through
manual insufflation of the lungs either by the rescuer blowing in to the
patient's lungs, or by using a mechanical device to do so. This method of
insufflation has been proved more effective than methods which involve
mechanical manipulation of the patients chest or arms, such as the Silvester
method.[3] It is also known as Expired Air Resuscitation (EAR), Expired Air
Ventilation (EAV), mouth-to-mouth resuscitation or colloquially the kiss of
life.
Neuroscience Study:
Neuroscience is the study of the nervous system -- including the brain, the
spinal cord, and networks of sensory nerve cells, or neurons, throughout the
body. Humans contain roughly 100 billion neurons, the functional units of the
nervous system. Neurons communicate with each other by sending electrical
signals long distances and then releasing chemicals called neurotransmitters
which cross synapses -- small gaps between neurons.
The nervous system consists of two main parts. The central nervous system is
made up of the brain and spinal cord. The peripheral nervous system includes the
nerves that serve the neck and arms, trunk, legs, skeletal muscles and internal
organs.
Online Resources:
http://www.usuhs.mil/nes/neuropage2.html
http://www2.umist.ac.uk/optometry/neuro_new/nsc_careers.htm
http://faculty.washington.edu/chudler/csem.html
http://neuroscience.owu.edu/careers.htm
http://en.wikipedia.org/wiki/Mechanical_ventilation
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