Bering Sea Fools Gold

At one time there was a sub-forum for commercial divers but it must not have gotten a lot of action so it is no longer I guess.
So I will just put this here and admin will move it if they like.

We all know made for TV reality shows play it up for the camera. I have had to sit through more episodes of crab fishin than I care to admit.

Great Lakes Warriors was another I could not keep from watching. My wife would have to take the kids to another room or even outside while I was watching because of my profuse swearing at the TV.
I worked with a good deal of those fellas and no nothing had changed since I quit them in the 90’s.

This gold dredging show is much the same. As a former military and civilian diver I can not keep from watching it.

Let me start by saying this…

BUY A FUCKING BAILOUT BOTTLE FOR CHRIST’S SAKE!!!

I have seen dumbass after dumb ass get himself in trouble and have to make an emergency ascent.
These dumbasses are lucky they are only working in less than 1 atmosphere.

But the disturbing trend is that now they are starting to go deeper.

Does anyone know if Nome, AK even has a hyperbaric chamber?
They are going to need one pretty soon.

I am shocked their have been no fatalities so far.

There should be some type of regulatory agency overseeing these guys to make sure they are fit to dive and also have the right equipment to do so.

Many years ago native divers along the Mosquito Coast were going deeper and deeper in search of spinney lobster to sell to Red Lobster.
They were coming up dead or if they were lucky just bent.
They used cocaine, weed, and whiskey to kill the pain and keep on keeping on.
Most enjoyed getting back to depth because that was the only place they got relief from their symptoms.

The natives were being taken advantage of by a couple white guys who gave a shit less about the natives and their families. All they wanted was lobster to sell so you could have your lobster dinner at Red Lobster for you anniversary or birthday.

Some ethical divers heard about what was happening and took it upon themselves to educate these natives about dive tables and they even raised enough money to have a hyperbaric chamber shipped in.
Many divers would still go way too deep so they could get the red gold that paid them so well but at least they had a decent chance of living when they came up bent.

There was a boycott by many divers against Red Lobster and as far as I am concerned there still is.
I have not eaten there in years.

Point of the anecdote being someone needs to step in and educate these divers. Even if they don’t want it then it needs to be forced upon them.

Their equipment needs to be certified as safe and the divers need to have some type of formal training before entering the water.

Some of these guys are working for someone else thus making them employees. Therefore they are governed by OSHA.
Even if they are being paid in cash then the “sub contractors” need to carry their own worker’s compensation insurance.
And you sure as hell ain’t getting insured by anyone I know running a ramshackle operation like the ones I continue to see time and time again.

It is not fair to the divers to have a supervisor that doesn’t know his ass from a snorkel. It is not fair to the families of these divers to not properly train these “divers” before letting them dive.

I would boycott something in protest if there was something to boycott but it is pretty hard to boycott gold.

However some of the equipment being bought, sold, and or traded is for purchase by certified divers only. Seems to me like it is a free for all up there.

What about MSA? They make sure all the other aspects of mining operations are safe and that the miners have at least basic training.
Seems to me that maybe they should take the lead with the USCG and any other government entity that can get involved to put a stop to these very dangerous diving ops.

I have seen guys surface dead as a doornail. It is something that haunts you forever. The deeper these “gold divers” go the more likely an “air embolism” or some other type of diving related illness is going to occur.

Oh, wait…that’s right…that kinda crap makes for better “Reality TV”.

GMAFB

Just one nobody’s opinion…

This would be a great opportunity for the noaa diving program to do some outreach in the form of education, but I don’t see it happening.

Well, I just wrapped up “Ice Diving Season II” …I think.

Two fellas did get pretty close to 1 atmosphere and one of them had enough sense to put on a sport dive computer to keep track of his tables.
Then I saw a younger fella that was a “GOM Commercial Diver”. He was pretty young. I am sure they worked the crap out of him in the gulf but if he was prospecting gold in Nome he must not have made his fortune in the oil patch like some of us other po dum country folk.

The younger fella had a bailout bottle but he trusted the regulator that was provided to him by a fat old man that never dove in his life let alone knowing the difference between an ice dive regulator and one you put on your skin diving rig.
He almost bit the dust when his regulator froze up.

Not one of these guys have I seen put some ol Jack in the volume tank of the comp.
That will keep everything from freezing up and you feel like having a Jack and Coke as soon as your dive is done.

The DNR must not let them bring in heavy equipment because I can think of an offshore dredge or two that could be converted to accommodate a sluice box and what not.
somebody would have already done that at the peak of gold prices.

Maybe not though.

And no chamber in Nome for sure. Maybe Anchorage but I doubt it.
Would have to find a Navy Salvage ship or get farther down the Coast to find one.
If you were lucky maybe a commercial dive op somewhere in the state could be found.

Forget that bro. We went into sat in dive school at one atmosphere. took a long time to saturate and a long time to decompress but the likelihood of getting bent was nil.
Plus it exposed anyone who was “pre-disposed” to getting bent, i.e. scar tissue from broken bone, old scar tissue from being bent before, and so on.

Plus we got to run tables that they only run on fellas who can not get relief. So when they are done running that table on you if you didn’t get relief you ain’t ever gonna get relief.

I’m out

[QUOTE=Veslog;146248]
I’m out[/QUOTE]

Thank God cause you confused the crap outta me!

[QUOTE=Veslog;143669]
I have seen guys surface dead as a doornail. It is something that haunts you forever. The deeper these “gold divers” go the more likely an “air embolism” or some other type of diving related illness is going to occur.
…[/QUOTE]
Actually …

An “air embolism” is more likely to occur the shallower you are. The first atmosphere is where there is the greatest volume change per foot of depth.

Just sayin’

[QUOTE=Veslog;146248] We went into sat in dive school at one atmosphere.[/QUOTE]

Most classrooms are at one atmosphere, especially when the windows are open.

Maybe you’ve been sitting at one bar for too long.

I don’t pretend to know everything. I know how to keep me and my dive team alive.

Excuse the 1 atmosphere thing. 35’ of sea water is technically two atmospheres.

I was not aware of the "first atmosphere is where there is the greatest volume change per foot of depth."
I never read that in Boyles Law or the Law of Partial Pressures.
Just sayin…

If I am sitting at a “bar” it is probably going to be a “sand bar”. Clean and sober since January 25th, 2007.

Reason for the “air embolism” comment on my part is the repeated “emergency ascents” made by these “divers”.

Once you get past the 1-2 atmosphere point an emergency ascent starts to become a very bad decision.
If you are lucky you get bent. If not so lucky…embolism.

To a trained diver an “emergency ascent” is a very last resort and to a commercial diver it is usually not an option at all unless you want to come up looking like a grouper you just pulled up from 600’ of sea water.

Even doing SurDives you can not come up any faster than 1’/second and you need to have your but in that chamber no more than 4 minutes from the time you “leave bottom”.

But what do I know…

      • Updated - - -

[QUOTE=Flyer69;146321]Actually …

An “air embolism” is more likely to occur the shallower you are. The first atmosphere is where there is the greatest volume change per foot of depth.

Just sayin’[/QUOTE]

I think you may be thinking of Shallow Water Black Out…but maybe not…

Embolism can occur at any depth in sea water or in the chamber…

peace

33 feet sea water is 2 atmospheres absolute, not 35 feet.

It’s funny you mention Boyle’s Law in conjunction with air embolism (which really should be described more accurately as an Arterial Gas Embolism), and not understand how the greatest risk for AGE is nearest the surface as opposed to at depth. I also guess you don’t understand the mechanism of injury.

Shallow Water Blackout? I am not confusing Arterial Gas Embolism with someone going unconscious as a result of decreasing PPO2 as they rise through the water column. (Hey, you brought up Partial Pressure Laws, not me.)

Sounds like your dive team is lucky to be alive, because your knowledge of diving physics and physiology is apparently wanting.

      • Updated - - -

[QUOTE=Veslog;146347]I don’t pretend to know everything. I know how to keep me and my dive team alive.

Excuse the 1 atmosphere thing. 35’ of sea water is technically two atmospheres.

I was not aware of the "first atmosphere is where there is the greatest volume change per foot of depth."
I never read that in Boyles Law or the Law of Partial Pressures.
Just sayin…

If I am sitting at a “bar” it is probably going to be a “sand bar”. Clean and sober since January 25th, 2007.

Reason for the “air embolism” comment on my part is the repeated “emergency ascents” made by these “divers”.

Once you get past the 1-2 atmosphere point an emergency ascent starts to become a very bad decision.
If you are lucky you get bent. If not so lucky…embolism.

To a trained diver an “emergency ascent” is a very last resort and to a commercial diver it is usually not an option at all unless you want to come up looking like a grouper you just pulled up from 600’ of sea water.

Even doing SurDives you can not come up any faster than 1’/second and you need to have your but in that chamber no more than 4 minutes from the time you “leave bottom”.

But what do I know…

      • Updated - - -

I think you may be thinking of Shallow Water Black Out…but maybe not…

Embolism can occur at any depth in sea water or in the chamber…

peace[/QUOTE]
Interesting.
Is the grouper’s distended swim bladder an anatomical feature shared by commercial divers?

Wow, I am impressed.

You lost me wit dem der big words

I digress…

I am a fake and my dive team is lucky to be alive…
I suck so bad

I am going to go eat a bullet now…goodbye cruel gcaptain thread…

Bye now. Don’t get pissy with me when you are the one puffing your chest out talking about “your” dive team. Implying you are the leader whose job is to keep your guy’s safe, right??

Dem der big words are your job to know. Not to mention the physics, physiology, and medical aspects of diving.

Ok so I was about to pull the trigger and I thought…why not google it first?

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Arterial Gas Embolism

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Arterial Gas Embolism
Pulmonary Barotrauma
References to Pulmonary Barotrauma
Reducing the Risks of PBT
Board Prep Summary

Arterial Gas Embolism

Pathophysiology

Arterial gas embolism is a major cause of death in diving and the initiating cause (pulmonary barotrauma) usually goes undetected. Caused most often by the expansion of respiratory gases during ascent, it also occurs when the breath is held during ascent from a dive, when there is local pulmonary pathology, when there is dynamic airway collapse in the non-cartilaginous airways and if there is low pulmonary compliance, particularly if this is not distributed evenly throughout the lungs. Boyle’s law is the physical law controlling the event. Experimental evidence indicates that intratracheal pressures of about 10 kPa (4 fsw or 1.22 m. or ascending from 170 feet or 51.82 m. to 120 feet or 36.58 m.) are all that’s needed for it to happen. Distention of the alveoli leads to rupture, alveolar leakage of gas, and extravasation of the gas into the arterial circuit.

Origin of Bubbles

Bubbles in the arterial circulation can arise from basically three sources: venous gas embolism with breach of the pulmonary vascular filter (paradoxic gas embolism), patent foramen ovale (paradoxic gas embolism) and tear of the pulmonary parenchyma with entry of gas into pulmonary venous outflow. Studies show that systemic venous bubbles are trapped in the pulmonary arterial tree and are usually completely eliminated from that site. The lung traps the air and excretes it into alveoli from the arterioles. (RG Presson, J Appl Physiol; 1989;67(5),1898-1902)

The syndrome of paradoxic air embolism (from septal defects) was first described by J. Cohnheim in 1877. (J Cohnheim, ZV Berline, Hirschwald, 1877;1:134). Hagan at the Mayo Clinic reported on 965 normal hearts and showed that more than 25% of patients with a history of cardiac disease have a ‘probe patent’ foramen ovale at autopsy. (PT Hagan, Mayo Clinic Proc, 1984; 59:17-20.).

The other main mechanism for arterial gas embolism is by way of the pulmonary overpressure syndrome or ‘burst lung’. This occurs from baropressure increases as the diver on compressed air ascends with a closed glottis or a free diver takes a breath of compressed air at depth and ascends. Because of Boyle’s law, maximal changes in volume occur in the 4 feet (1.22 m.) closest to the surface and the diver sustains a tear in the pulmonary parenchyma with the escape of air into the pulmonary venous outflow. This can result in several outcomes: pneumothorax (collapsed lung), pneumomediastinum (air in the space around the heart), subcutaneous emphysema (bubbles of air in the fatty tissues under the skin) and air into the pulmonary capillaries.

As the diver takes his first breath after surfacing, the extra-alveolar gas enters the torn blood vessels, migrates to the left side of the heart and is distributed systemically as emboli sent to areas determined by buoyancy.

Arterial gas emboli arise from gas bubbles in the pulmonary capillaries => pulmonary veins to the left side of the heart =>possible coronary artery emboli (rare) or internal carotid and vertebro-basilar arteries to thebrain => cerebral artery embolism (blockage) with the clinical picture of a stroke.

The foam or bubbles block arteries of the 30-60 micron caliber and cause distal ischemia, with astrocyte and neuronal swelling. As the bubble passes over the endothelium, there are direct cellular effects (within 1-2 minutes) causing PMN stimulation. The bubble itself has surface effects causing local swelling, downstream coagulopathy with focal hemorrhages. There is immediate increased permeability of the blood-brain barrier, loss of cerebral auto-regulation, rise in CSF and a rise in the systemic blood pressure. A phenomenon called ‘no-reflow’ occurs with a post-ischemic impairment of microvascular perfusion. This is thought to be the result of FactorVIII interacting with the prostaglandin system and possibly other blood/tissue factors.

Clinical Manifestations

The clinical manifestations of cerebral gas embolism include a sudden onset of unconsciousness associated with a generalized or focal seizure. There is often confusion, vertigo (extreme dizziness) and cardiopulmonary arrest. In a series of 24 USN cases in which the time was known, 9 occurred during ascent in the water, 11 within one minute at the surface and 4 occurred within 3-10 minutes at the surface.

Other clinical manifestations include the sudden onset of hemiplegia (paralysis on one side), focal weakness, focal hypesthesia (loss of feeling), visual field defect (blank areas in vision), blindness, headache and cranial nerve defects (vision, hearing, eye movements, facial muscles and feeling). The operative word here is “sudden”–nearly all of these symptoms can also be caused by neurological decompression sickness. Less common manifestations are chest pain and bloody, frothy sputum.

Management Outline

Recognition This usually occurs during or immediately after surfacing

•Symptoms
• Bloody froth from mouth or nose
• Disorientation
• Chest pain
• Paralysis or weakness
• Dizziness
• Blurred vision
• Personality change
• Focal or generalized convulsions
• Other neurological abnormalities
• Hemoptysis (bloody sputum)
• Signs
• Bloody froth from nose or mouth
• Paralysis or weakness
• Unconsciousness
• Convulsions
• Stopped breathing
• Marbling of the skin
• Air bubbles in the retinal vessels of the eye
• Liebermeister’s sign (a sharply defined area of pallor in the tongue).
• Death

Early management

•CPR, if required
• Open airway, prevent aspiration, intubate if trained person available
• Give O2, remove only to open airway or if convulsions ensue.
• If conscious, give nonalcoholic liquids
• Place in horizontal, neutral position
• Restrain convulsing person loosely and resume O2 as soon as airway is open.
• Protect from excessive cold, heat, water or fumes.
• Transport to nearest ER for evaluation and stabilization in preparation for removal to the nearest recompression chamber.
• Call DAN (919-684-9111) or your own preferred emergency number
• Air evacuation should be at sea level pressure or as low as possible in unpressurized aircraft
• Contact hyperbaric chamber, send diver’s profile with the diver,and send all diving equipment for examination or have it examined locally.

Treatment
Recompression as soon as possible
Oxygen
Cautious hydration

Pulmonary Barotrauma

Scenario

A 25 year old divemaster made one dive to 40 feet for 38 minutes and then spent 3 hours and 45 minutes on the surface. His second dive was to 55 feet for 27 minutes, at the end of which he struggled with a heavy anchor, swimming with it to the surface. At the surface he raised out of the water, yelled, became comatose and was pulled from the water. apparently convulsing. He was placed in the head low position, given O2 by mask and on arrival at a recompression chamber 50 minutes later, he was alert, oriented and really felt well. He complained of a slight numbness of both right extremities but otherwise had a normal exam. Is this DCS, epilepsy or pulmonary over-pressure? What is the one clue you need to make the diagnosis?

This diver obviously had a pulmonary overpressure accident with arterial gas embolism and was treated by placing him on Table 6A ( 165 feet for 30 minutes) and then on Table 6. The fact that it occurred immediately on surfacing indicates that it’s not DCS and surely a person with epilepsy should never have been certified as a divemaster.

Prevention

This episode underlines the potential risk of pulmonary overpressure accidents on every compressed gas dive regardless of depth and time. Prevention of pulmonary overpressure accidents starts with a good diving physical exam to ensure no history of pulmonary pathology which would prevent free pressure equilibration of all parts of the lungs as well as psychological evaluation of propensity to panic. The scuba instructor has in his hands the final prevention by teaching the dangers of breath-holding.

Mechanisms of Action

The mechanisms that occur when a pulmonary overpressure accident occurs are directly related to Boyle’s Law, and the greatest danger is at shallow depths-with the greatest gas volume expansion near the surface. Boyle’s Law states that with the temperature constant, the volume of a gas is inversely proportional to the pressure. When pressure differential between gas in alveoli and water (or chamber gas pressure in a compression chamber) exceeds 50-100 mmHg (3 to 5 FSW),free gas can be forced across the fine alveolar membrane into pulmonary interstitial tissues, pulmonary capillaries or rarely through the path of greatest resistance, the visceral pleura.

End Result
The results of this air movement across
these natural barriers are:

1). Arterial gas embolism,
2). Mediastinal and subcutaneous emphysema, and
3). Pneumothorax.

Arterial gas emboli

Arterial gas emboli arise in the gas bubbles in the pulmonary capillaries -> pulmonary veins to the left side of the heart->possible coronary artery emboli or internal carotid and vertebro-basilar arteries to the brain-> cerebral artery embolism with the clinical picture of a stroke.

The clinical manifestations of cerebral gas embolism include a sudden onset of unconsciousness associated with a generalized or focal seizure. There is often confusion, vertigo and cardiopulmonary arrest. In a series of 24 USN cases in which the time was known, 9 occurred during ascent in the water, 11 within one minute at the surface and 4 occurred within 3-10 minutes at the surface.

Other clinical manifestations include the sudden onset of hemiplegia, focal weakness, focal hypesthesia, visual field defect, blindness, headache and cranial nerve defects. The operative word here is “sudden”-nearly all of these symptoms can also be caused by neurological decompression sickness. Less common manifestations are chest pain and bloody, frothy sputum.

An Unusual Case of Cerebral Gas Embolism
A snorkeler takes a breath from a compressed air regulator at depth.

Emphysema

Mediastinal and subcutaneous emphysema, due to bubbling in the tissues, cause substernal pain, subcutaneous crepitus (a crunching feeling ), a definite x-ray appearance and occasionally circulatory embarrassment (rare).

Pneumothorax

Pneumothorax occurs when the visceral pleura is ruptured by the air pressure and the lung collapses. When this occurs there is pain, decreased respiration on the affected side, changes to auscultation and percussion on physical exam with typical x-ray findings. If the opening is large-a tension pneumothorax can occur, requiring tube decompression of the chest before treatment with the compression chamber.
Spontaneous pneumothorax

Precipitating Factors

All of these things can happen when two precipitating factors occur:

1). Breath-holding ascent

2). Local air trapping

A breath-holding ascent occurs in association with panic, buddy-breathing and acute laryngospasm (a breath of sea water). Local air trapping is the result of bronchospasm (asthma), mucous plugs (post-bronchitis), blebs (blisters on the surface of the lung), air-containing pulmonary cavities(as in scarring from TB), and very often no reason whatsoever.

Sarcoidosis
Marfan’s Syndrome
Cystic Fibrosis
Asthma

Treatment

Treatment of these three entities varies from the simple ( bedrest, O2, and observation for the emphysema) to immediate compression to 6 ATA and resuscitation while in transport for the arterial gas embolism. A chest tube is standard care for pneumothorax with a good neurological exam to rule out cerebral embolism.

Compression takes precedence over treatment of the pneumothorax and mediastinal emphysema and frequently attendants must also treat coexistent near-drowning, using endotracheal tube, 100% oxygen and IV fluids and dexamethasone.

Our young divemaster had a close encounter with the ghost of Sir Robert Boyle when he apparently held his breath while straining to swim to the surface with the anchor. The lessons of this episode should be readily apparent and can be acted upon by all of us, no matter how experienced we think we are.

*Recent Reference

Coxson HO, Rogers RM, Whittal KP, et al: A
Quantification of the Lung Surface Area in Emphysema Using
Computed Tomography. Am J Respir Crit Care Med
159(3):851-856, 1999.

References to Pulmonary Barotrauma

J Emerg Med 1998 May-Jun;16(3):413-7
Fatal pulmonary barotrauma due to obstruction of the central circulation with air.
Neuman TS, Jacoby I, Bove AA

Hyperbaric Medicine Center and Department of Emergency Medicine, University
of California Medical Center, San Diego, USA.

Cardiac arrest in cases of barotraumatic arterial gas embolism (AGE) is usually
ascribed to reflex dysrhythmias secondary to brainstem embolization or secondary
to coronary artery embolization. Several case reports suggest that obstruction of
the central circulation (i.e., the heart, pulmonary arteries, aorta, and arteries to the
head and neck) may play a role in the pathogenesis of sudden death in victims of
pulmonary barotrauma. We report three consecutive cases of fatal AGE in patients
in whom chest roentgenograms demonstrated confluent air lucencies filling the
central vascular bed, the heart, and great vessels. In none of the victims was there
evidence by history or at autopsy that the intravascular gas was iatrogenically
introduced. Total occlusion of the central vascular bed with air is a mechanism of
death in some victims of AGE, and resuscitation efforts for such patients should take this possibility into consideration.

Undersea Hyperb Med 1997 Winter;24(4):301-8
Recompression treatments during the recovery of TWA Flight 800.
Leffler CT, White JC
Medical Department, Naval Amphibious Base Little Creek, Virginia, USA.

After the crash of TWA flight 800, U.S. Navy (USN) and civilian divers recovered
the aircraft and the victims’ remains from 117 feet of sea water (fsw). Safety
information was gathered from observations, interviews, and medical and diving
records. Of 752 dives employing surface decompression using oxygen (SDO2), 10
divers required recompression treatments, mainly for type 2 decompression
sickness (DCS). When using hot water heating, the DCS risk was high until the
dive profiles were modified. Divers made nearly 4,000 no-decompression scuba
dives. In eight scuba divers and one tender treated with recompression, the
diagnoses included DCS (3), arterial gas embolism (AGE) (1), and vascular
headache (2). All USN divers recovered fully. The experience is consistent with
previous work suggesting an increase in DCS risk in warmer SDO2 divers. The
USN SDO2 tables can be made safer by limiting bottom time and extending
decompression. Even under stressful conditions, rapid ascents resulting in AGE are
uncommon. Vascular headaches can mimic DCS by responding to oxygen.

Aviat Space Environ Med 1997 Nov;68(11):1025-8
Neurological manifestation of arterial gas embolism following standard altitude chamber
flight: a case report.
Rios-Tejada F, Azofra-Garcia J, Valle-Garrido J, Pujante Escudero A
Centro de Instruccion de Medicina Aeroespacial (C.I.M.A.), Madrid, Spain.

In the course of a decompression at flight level 280 (28,000 ft) in an altitude
chamber flight, a 45-yr-old cabin air traffic controller developed sudden numbness
in his left upper and lower extremities and, soon after, complete paralysis in the
left side, dysarthria and left facial palsy. A presumptive diagnosis of arterial gas
embolism (AGE) was made and hyperbaric oxygen therapy (HBO) was given after
airevac of the patient to the closest compression facility. Complete resolution of
the symptoms was obtained after treatment Table VI-A (extended), plus 3
consecutive HBO treatments (90 min of Oxygen at 2.0 ATA). AGE is a rare event
in the course of regular altitude chamber flight and diagnosis should be done in the
context of the barometric pressure changes and an acute cerebral vascular injury.
Risk factors and follow-up diagnostic procedures are discussed.

Chest 1997 Sep;112(3):654-9
Risk factors for pulmonary barotrauma in divers.
Tetzlaff K, Reuter M, Leplow B, Heller M, Bettinghausen E
Department of Diving and Hyperbaric Medicine, Naval Medical Institute, Kiel,
Germany.

STUDY OBJECTIVES: Pulmonary barotrauma (PBT) of ascent is a feared
complication in compressed air diving. Although certain respiratory conditions are
thought to increase the risk of suffering PBT and thus should preclude diving, in
most cases of PBT, risk factors are described as not being present. The purpose of
our study was to evaluate factors that possibly cause PBT. DESIGN: We analyzed
15 consecutive cases of PBT with respect to dive factors, clinical and radiologic
features, and lung function. They were compared with 15 cases of decompression
sickness without PBT, which appeared in the same period. RESULTS: Clinical
features of PBT were arterial gas embolism (n=13), mediastinal emphysema
(n=1), and pneumothorax (n=1). CT of the chest (performed in 12 cases) revealed
subpleural emphysematous blebs in 5 cases that were not detected in preinjury and
postinjury chest radiographs. A comparison of predive lung function between
groups showed significantly lower midexpiratory flow rates at 50% and 25% of
vital capacity in PBT patients (p<0.05 and p<0.02, respectively).
CONCLUSIONS: These results indicate that divers with preexisting small lung
cysts and/or end-expiratory flow limitation may be at risk of PBT.

Tetzlaff K, et al. [See Related Articles]Risk factors for pulmonary barotrauma in divers.
Chest. 1997 Sep;112(3):654-9.
Raymond LW. [See Related Articles]Pulmonary barotrauma and related events in divers.
Chest. 1995 Jun;107(6):1648-52.
Reuter M, et al. [See Related Articles]Computed tomography of the chest in diving-related pulmonary barotrauma.
Br J Radiol. 1997 May;70(833):440-5.
Tetzlaff K, et al. [See Related Articles][Diving-associated pulmonary barotrauma as a rare differential diagnosis in internal medicine-pneumologic ambulatory care].
Pneumologie. 1996 Dec;50(12):902-5. German.
Lim EB, et al. [See Related Articles]A review of cases of pulmonary barotrauma from diving.
Singapore Med J. 1993 Feb;34(1):16-9.
Bove AA. [See Related Articles]Pulmonary barotrauma in divers: can prospective pulmonary function testing identify those at risk?
Chest. 1997 Sep;112(3):576-8.
Tetzlaff K, et al. [See Related Articles]Pulmonary barotrauma of a diver using an oxygen rebreathing diving apparatus.
Aviat Space Environ Med. 1996 Dec;67(12):1198-200.
Neuman TS, et al. [See Related Articles]Recommend caution in defining risk factors for barotrauma in divers.
Chest. 1998 Dec;114(6):1791-3.

Reducing the Risks of Pulmonary Barotrauma

Medical Factors

History
The same conditions that cause spontaneous pneumothorax can be deadly in the increased ambient pressures of diving - and even in the pressure changes that take place in pressurized aircraft. Awareness of these conditions that can lead to spontaneous pneumothorax might aid in the reduction of the risk of ‘burst lung’ and cerebral arterial gas embolism.

Some of these conditions and diseases include:

Asthma, COPD, mucoviscidosis (cystic fibrosis), Pneumocystis carinii, tb, bronchiolitis (smokers), viral lower airway disease, HIV infection, bronchial atresia, sports blunt trauma, weight lifting, metastatic tumors, catamenia (perimenstrual), empyema, bullous emphysema (juvenile, apical, generalized), Marfan’s syndrome, Schistosome infestation, Pregnancy, cryptogenic fibrosing alveolitis, and pulmonary histiocytosis X, Congenital bronchopulmonary cystic disease, vibroacoustic disease, alveolar proteinosis, bronchiectasis

 Symptoms of emphysema include: 
  Cough 
  Wheezing 
  Shortness of breath 
  Blue or pink discoloration of the nail beds or lips (blue bloater or pink puffer) 
  Smoking 
  Exposure to chemical or commercial agents 

Examination

     Prolonged expiratory phase in breathing 
      Audible wheezing and rhonchi (rattles) 
      Auscultatory rales (stethoscope findings by the physician) 
      Increased AP diameter chest 
      Clubbing (fingernails rounded and tips of fingers widened) 
      Nail bed and lip color changes 
      Percussive changes in the lung fields (tonal reverberations) 

Studies

    Spiral (helical) CT (probably the best to rule out pulmonary blisters) 
      Chest x-ray 
      Pulmonary functions 
       Lung scan 
       Xe-CT ventilation studies 
       Forced Expiratory Volume 
       Computer-Assisted MT 
       Maximal Midexpiratory Flow Rate 
       Tomography, X-Ray Computed 
       Vital Ca pacity 
       Body plethysmography 
       spirometry 
       metacholine airway provocation. 

Diver Factors
Awareness of cause of problem (ascending from depth with a closed air-containing chamber)
Gear failure
Breath holding on ascent
’Sipping’ from a regulator by a free diver
Weight lifting from depth
Boat exits in heavy wave action
-ascend anchor line for stability
-continue to breathe via regulator until you are out of the water
Straining while removal of gear (fins, weight belt) in the water
Poor air management, avoid running out of air
Panic ascents
Faulty buddy breathing practices

References and abstracts for Spiral CT scan

Title
Air trapping on expiratory high-resolution CT scans in the absence of inspiratory scan
abnormalities: correlation with pulmonary function tests and differential diagnosis.
Author Arakawa H; Webb WR
Address Department of Radiology, University of California, San Francisco 94143-0628, USA.
Source AJR Am J Roentgenol, 170(5):1349-53 1998 May
Abstract
OBJECTIVE: We wish to describe the differential diagnosis and pulmonary function
correlates of patients with normal findings on inspiratory high-resolution CT (HRCT) scans
who showed air trapping on expiratory scans. CONCLUSION: Air trapping on expiratory HRCT scans in patients with normal findings on inspiratory scans is most often associated with bronchiolitis obliterans and asthma. Obtaining expiratory scans in patients who may have one of these diseases recommended.

Title Preoperative and postoperative imaging in the surgical management of pulmonary
emphysema.
Author
Slone RM; Gierada DS; Yusen RD
Address
Mallinckrodt Institute of Radiology, Barnes-Jewish Hospital, Washington University School of
Medicine, St. Louis, Missouri, USA.
Source
Radiol Clin North Am, 36(1):57-89 1998 Jan
Abstract
For patients with emphysema, imaging studies have been useful for diagnostic purposes and for
preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation,
and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory
films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

Title [Dynamic computed tomography in the study of bronchiolitis obliterans] 

Author
Zompatori M; Poletti V; Battista G; Canini R; Bruscoli P; Carfagnini F
Address
Radiologia Padiglione Pneumonefrologico, Policlinico S. Orsola-Malpighi, Bologna.
Source
Radiol Med (Torino), 94(4):308-14 1997 Oct
Abstract
Obliterative or constrictive bronchiolitis is characterized by narrowing of the small airways, due
to submucosal and peribronchiolar fibrosis, with chronic obstruction. The vast majority of cases
of bronchiolitis obliterans are associated with other diseases and only few cases are idiopathic.
We report on the main computed tomography (CT) methods used study obliterative
bronchiolitis, the CT findings and the differential diagnosis with other diseases. The combination of HRCT, rapid volumetric scanning and advanced image display is a powerful tool study the normal and abnormal features of bronchiolar function and alveolar ventilation.

Title Expiratory CT scans for chronic airway disease: correlation with pulmonary function test 
 results. 

Author
Lucidarme O; Coche E; Cluzel P; Mourey-Gerosa I; Howarth N; Grenier P
Address
Department of Radiology, Universit´e Pierre et Marie Curie, H^opital de la Piti´e-Salp^etri`ere,
Paris, France.
Source
AJR Am J Roentgenol, 170(2):301-7 1998 Feb
Abstract
OBJECTIVE: The purpose of our study was to correlate findings on expiratory CT scans with
results of pulmonary function tests (PFTs) and to determine whether these techniques may be
complementary in assessing airway obstruction.
CONCLUSION: Air trapping may permit detection of airway obstruction in patients with
clinically suspected chronic airway disease even when PFTs are normal. Furthermore,
expiratory CT allows one to calculate a reduction score for a cross-sectional lung area that
appears to be better correlated with the degree of airway obstruction measured on PFTs.

Title
Air trapping in children: evaluation with dynamic lung densitometry with spiral CT.
Author
Johnson JL; Kramer SS; Mahboubi S
Address
Department of Radiology, Children’s Hospital of Philadelphia, PA 19104, USA.
Source
Radiology, 206(1):95-101 1998 Jan
Abstract
PURPOSE: To evaluate the feasibility of the use of a simple method of dynamic lung
densitometry with spiral computed tomography (CT) to differentiate air trapping from
compensatory hyperinflation in children.
CONCLUSION: Dynamic spiral CT lung densitometry is a quick, simple method for quantitative confirmation of the presence of air trapping and differentiation from compensatory hyperinflation.

Title
[Quantitative assessment of pulmonary emphysema with computerized tomography.
Comparison of the visual score and high resolution computerized tomography, expiratory density mask with spiral computerized tomography and respiratory function tests]
Author
Zompatori M; Battaglia M; Rimondi MR; Fasano L; Cavina M; Pacilli AM; Guerrieri A; Fabbri
M; Vivacqua D; Biscarini M
Address
Radiologia padiglione Pneumonefro, Policlinico S. Orsola-Malpighi, Bologna.
Source
Radiol Med (Torino), 93(4):374-81 1997 Apr

Wow…he was right!
Should I blow myself away because they never taught us in dive school that the last 4 fsw are potentially the most dangerous?
Or should I not because google says it can happen at any depth, seawater or chamber?

Should I blow myself away because I didn’t use A.G.E instead of air embolism?

I got a better idea. I will push myself down to 500 fsw on mixed gas and stay there for uhhh…let’s say a day.
Then I will take a fire ax and smash a port hole out!

Ok, this is where I need some help…

Will I get sucked through the port hole or explode in the chamber?

How about if I was on a Bell Sat mixed gas dive and I decided to “surface” after being in sat at 300 fsw for the last uhhhh…let’s say two weeks?

Would I look like a fish’s swim bladder or would I explode?

anybody?..Buelller?..anyone?

Don’t you love google? A few minutes on google and anyone can be an expert! and you don’t even have to pay your dues! I like how some of your “terms” came almost directly from this article.
Are you a DMO?
Wow…you must be with all those big words you found on google.

I guess we are both right.
Point being emergency ascents in shallow or deep water not a good idea.

But let me get back to killing my dive team…we do that for fun…well I mean besides hyperbaric experiments with stray animals that is…

was that too “pissy”? I would hate to offend someone that has their shit together as much as you…

I am glad you know how to use google to learn about things you didnt know before.

The point being, I knew all that stuff back in the 80’s waaay before there was google. As a dive leader and instructor it was required to know these things. Without google. The “terms” were in common use waaay before google, or that wiki was written.

So. Do you feel better now?

I am hoping you understand now why Boyle’s Law says that it would take a 50 foot change of depth at 170 feet to have the same effect as only a 4 foot change of depth right below the surface. This was the point of my first reply to your misinformed pronouncements at the beginning of the thread. And guess what, I didn’t need google for that either.

Don’t worry about offending me, I am getting a lot of entertainment out of making you look dumb. Don’t get me started on what you gotta do to make a regulator suitable for ice diving. It’s not that complicated.

[QUOTE=Flyer69;146377] I am getting a lot of entertainment out of making you look dumb.[/QUOTE]

While it might be entertaining, it sure as Hell isn’t hard work. He is doing most of the heavy lifting all by himself.

He sounds like he took a resort diving course a few years ago.

Yeah. I have taught the resort class to little old grannies who had a better understanding
of Boyle’s Law than this knucklehead.

Hey dude, you asked if I was a DMO? The short and sweet answer is, NO. But, I got my start diving with and learning from some people mentioned in your cut and paste results from your Google search above. The people who taught me what I know about diving physics, physiology, and medicine all have one thing in common: NOGI

And I can guarantee you that none of them needed to use Google either.

Yeah, he’s doing a lot of the work here, but what about all that effort I have to expend on Google? It’s not easy being an instant expert!

[QUOTE=Flyer69;146371]Bye now. Don’t get pissy with me when you are the one puffing your chest out talking about “your” dive team. Implying you are the leader whose job is to keep your guy’s safe, right??

Dem der big words are your job to know. Not to mention the physics, physiology, and medical aspects of diving.[/QUOTE]

Wow, did you really see me “puffing my chest out”. How did you hack my web cam? O jeez you didn’t see that thing with the dog and the peanut butter did you?
I always thought those people on the TV could see me but now I know!

Where did I put my tin foil hat?

Can I get a commercial dive job with my club med 1 day scuba cert?

Anyone want to join my dive team? Me smart and me keep you alive…

My drone can see through walls.
Your dog says stop buying the chunky peanut butter.