Lungs collapsing??

[MEGALEF]

Here it is. This month's (probably stupid) question from me.

A guy in my judo class is a teacher at a school for aggressive kids and has had to employ grappling many times in his work. While learning entries into kesa gatame we talked about how the club's old heavyweight judokas would practically tap you out by sheer constriction from there. He then told me that at a course he had received at work the course leader had told him never to put heavy pressure on the chest of someone being held down. The reason for this was that if the person screamed and resisted too much, he could make his own lungs collapse.

Is there any truth to this or is it bullshido?

[dakotajudo]

Not unless he cracks a rib, and it punctures a lung. There's a layer of connective tissue that holds something of a vacuum between the ribs and the lungs themselves. If this vacuum is lost the lung will collapse.

There is clinical evidence that a person resisting too much in a constricting hold can become acidotic; a potentially fatal condition. This, however, comes from people put into straightjackets, probably a little more restrictive, and held for a longer period of time.

[unpossible]

can become acidotic

Is that what the constantly crying baby was doing to himself in The Andromeda Strain?

[Yamabushi]

The mechanism of death from being restrained on your front is related to physical restriction of chest movement. It can occur when someone is held face down and their arms are held behind their back. Because of the anatomy of the human chest the postion prevents adequate chest movement and eventually the victim suffocates. It can be exacerbated by someone applying weight by lying or sitting on the victims back.

The problem is worsened because people who can't breathe normally start to struggle harder which makes the restrainers apply more force. The victim then asphyxiates and suffers a seizure as a result of lack of oxygen to the brain. The movements associated with the fit are often perceived as further resistance and the fact that the victim is, in fact, dead isn't picked up until it's too late to do anything meaningful about it.

This is also the mechanism of death in crucifixion.

Medics call a "collapsed lung" a pneumothorax and it occurs because air enters the space between the lung the chest wall and prevents the lung from properly reinflating. If you're unlucky there is a valve effect (most commonly because of penetrating trauma like a gunshot wound or stab) and the collapse is rapid and gets worse with each breath. Death in this case occurs not because of lung collapse but because the air in the chest cavity squeezes the heart and aorta and causes them to tear or fail.

It's unlikely that being restrained and screaming a lot would cause death by pneumothorax.

[Yamabushi]

Is that what the constantly crying baby was doing to himself in The Andromeda Strain?

Acidosis occurs for two reasons:

1. You are unable to clear enough carbon dixode from your lungs and so you develop a respiratory acidosis
2. You are making more acid than your body can clear and you get a metabolic acidosis

Respiratory acidosis only occurs if you having breathing difficulties so it wouldn't be that. In normally healthy people metabolic acidosis normally only occurs as a result of exercise (hello lactate) or because blood flow is restricted to a leg or arm for some reason (like being crushed or getting drunk and falling asleep on the toilet for hours).

[dakotajudo]

The mechanism of death from being restrained on your front is related to physical restriction of chest movement. It can occur when someone is held face down and their arms are held behind their back. Because of the anatomy of the human chest the postion prevents adequate chest movement and eventually the victim suffocates. It can be exacerbated by someone applying weight by lying or sitting on the victims back.

Positional asphyxia isn't really appropriate in this case.

Kesa-gatame is performed with uke on his back, and there is typically minimal restaint on the neck - uke is controlled mostly by pressure on the rib cage, just under the armpit. Uke is also, in most cases, somewhat acidotic due to exercise.

The Kodokan did a physiological study of various techniques, including hold-downs (though not specifically kesa). Even though restrained, ukes respiration was typically double that of resting, but a half to third of what was normal for standing activity. In contrast, metabolic rate was 5-10 X greater than comparable standing activity. This combination suggest metabolic acidosis, not hypoxia.

It is possible to perform kesa with a flexion of the head onto the chest, which can contribute to asphyxiation, but that's not what's described in the original post.

This is also the mechanism of death in crucifixion.

Not really.

Crucifixion as marked by exhaustion asphyxia. The postion does not allow for passive exhalation; exhalation is diaphragmatic. To aid exhalation, the victim would lift themselves with their arms and legs (and, since the limbs would be nailed and frequently broken, this was very painful). Eventually, the victim becomes to fatiqued to move. Hypovolumic shock, due to scourging and dehydration, probably contributes to death as well.

Positional asphyxia, on the other hand, is a restraint against inhalation. Wouldn't really call it the same mechanism.

Medics call a "collapsed lung" a pneumothorax and it occurs because air enters the space between the lung the chest wall and prevents the lung from properly reinflating.

Lungs collapse because the surface tension in the alveoli; an negative interpleural pressure is required to conteract the surface tension. During pneumothorax, the negative pressure is lost. Your description sounds as if a positive pressure is what causes the lung to collapse.

If you're unlucky there is a valve effect (most commonly because of penetrating trauma like a gunshot wound or stab) and the collapse is rapid and gets worse with each breath. Death in this case occurs not because of lung collapse but because the air in the chest cavity squeezes the heart and aorta and causes them to tear or fail.

I don't think that's likely - the heart and aorta are much too muscular to be collapsed by a tension pneumothorax (pressure is, what, 20-30 mmHg?). Pulmonary veins, on the other hand, collapse under relatively low pressures.

It's unlikely that being restrained and screaming a lot would cause death by pneumothorax.

Yeah.

[dakotajudo]

Is that what the constantly crying baby was doing to himself in The Andromeda Strain?

Actually, in the book, the pH of the crying baby went the opposite. It was the drunk who was acidotic.

[MEGALEF]

exacerbated - To increase the severity, violence, or bitterness of; aggravate: a speech that exacerbated racial tensions; a heavy rainfall that exacerbated the flood problems.
asphyxiate - v. tr.
To cause asphyxia in; smother.
v. intr.
To undergo asphyxia; suffocate.
pneumothorax - Accumulation of air or gas in the pleural cavity, occurring as a result of disease or injury, or sometimes induced to collapse the lung in the treatment of tuberculosis and other lung diseases.

acidotic - An abnormal increase in the acidity of the body's fluids, caused either by accumulation of acids or by depletion of bicarbonates.
hypoxia - Deficiency in the amount of oxygen reaching body tissues.
hypovolumic - hypovolemic? - adj : of or relating to a decrease in the volume of circulating blood
interpleural - Function: adjective
: situated within, occurring within, or administered by entering the pleura or pleural cavity

Thank god for dictionary.com.

Thank you.

[Yamabushi]

Lungs collapse because the surface tension in the alveoli; an negative interpleural pressure is required to conteract the surface tension. During pneumothorax, the negative pressure is lost. Your description sounds as if a positive pressure is what causes the lung to collapse.

The mechanisms of collapse in atelectasis and pneumothorax are different. Collapse of the alveoli occurs because the pressure generated duting inspiration cannot overcome the surface tension that holds the surface of the alveoli together after exhalation. In normal health the lungs produce surfactant that reduces that surface tension and makes it easier to inhale. I've only aware of alveolar collapse as a major source of pulmonary problems in people with pneumonia or acute respiratory distress syndrome. It's commonly treated by maintaining positive pressure at the end of expiration to help the alveoli remain open.

In pnuemonthorax the contact between the surface of the pleura and the chest wall is lost because of positive pressure occuring in the pleural space. As a result the lung collapses like a balloon. The space it had occupied is the filled with air under atmospheric pressure (which is positive compared to the normal negative pressure of the chest cavity).

I don't think that's likely - the heart and aorta are much too muscular to be collapsed by a tension pneumothorax (pressure is, what, 20-30 mmHg?). Pulmonary veins, on the other hand, collapse under relatively low pressures.

As the space previously occupied by lung fills with air it pushes all the internal structures in the chest out of place. This is visible as a deviation of the trachea from the centreline. The effect on the heart is to apply a tamponade effect where with each contraction less blood is able to enter the ventricles and so contractions generate less stroke volume until effective perfusion is lost and death occurs.

Obviously collapse of the vena cava and the pulmonary circulation under pressure will further reduce venous return and worsen the effect.

The aorta, although extremely elastic, is vulnerable to shearing at the point where it joins the heart. It is not the air pressure itself that does the damage but the shifting of the chest contents out of alignment. Although this is uncommon in tension pneumothorax it can occur. It's more commonly seen as the cause of death in deceleration injuries.

[Yrkoon9]

A long time ago I took an anatomy class. During the test you wandered around the room and named all the specific points on different bones, skeletons, models, etc. There was a pointer at this one spot and I could not figure out what the hell the teacher was looking for.

So I went out on a limb and labelled the arrow: Abnopelvic region.

I got no points for that answer.