RE: [PSUBS-MAILIST] Perry lockout

Joe,

The whole sat operation is run by topside personnel which today includes a diving medical technician (DMT). Most sat divers grin and bear some of the smaller “hits” received as the treatment is often worse than the treatment. Many of today’s tech divers are prepared to re-enter the water and complete emergency deco (usually with oxygen) which is frond upon by the commercial and military communities. Often 100% oxygen taken at the surface prior to the onset of signs and symptoms of an expected deco incident can mitigate the hit.

A well prepared PSUB dive operations guidelines book should include contingency plans, one of which would be emergency deco after an incident (flooding and free ascent escape, pressurized gas leak into the hull, etc.). A diving instructor trainer that I worked with years ago in southern Florida who was also an anesthesiologist analyzed dive accidents in SF and determined that it took a minimum of 3 hours from the onset of a deco incident until the patient was in a chamber. Issues that contributed to this length of time included the patient relating the pain to a deco incident vs. a normal pain incurred as part of diving, water transport time (helos are not always immediately available), road transport time, availability of a chamber (many chambers have closed over the years due to the cost and liability, the chamber is down for repairs, or occupied by another patient most often not related to diving), activation of the chamber, and getting the staff on site. So 3 hours oxygen delivered at 100% concentration is the minimum that should be available on the surface in case of an emergency.

As to free ascents, US and UK subs have an engraved table outside and inside of the escape chamber that tells how long you have a various depths to “press down”, make your buoyant free ascent escape, and still probably not exhibit signs of deco sickness. It would be interesting to acquire a copy of this table to include in a PSUB’s Operations Manual. One thing to keep in mind at greater depths is that your ear drums will probably be ruptured by the rapid pressurization necessary to equalize ambient and internal pressures so that hatch can be opened to make the escape. This is a very stressful event and the 2^nd person out usually experiences much more difficulties than the person directly below the escape hatch. This is a good case for practice walk-throughs and if possible real practice escapes by PSUB crews under non-emergency conditions…at a minimum, a deep conversation should entail between crew members to explore all of the issues that might be encountered in during an escape op.

R/J²

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

It is the mark of an educated mind to be able to entertain a thought without accepting it.
- Aristotle

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph Perkel
Sent: Sunday, January 28, 2007 1:02 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Perry lockout

Jay,

When you professional Sat divers are working, are there personnel topside trained in dive physiology and medicine to make a quick call as to what treatment for x incident should be employed? Individual history can also be a big factor here.

This is applicable to psubbers in the event of an incident /accident at depth in that where you live and operate, can make quite a difference. For example, here in Florida, diving accidents are expected, and appropriate facilities / personnel available. Quick transport via C.G. helo, is a VHF call away. We are very very fortunate in that regard.

Joe

From: "Jay K. Jeffries" <bottomgun@mindspring.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] Perry lockout
Date: Sun, 28 Jan 2007 12:08:41 -0500

In diving and other hyperbaric scenarios there are two types of oxygen poisoning that can occur. The first, more common, is a result of high O₂ partial pressure at depth and results in aberrations of the body’s chemistry causing neurological difficulties (convulsions being the worse and can result in death rapidly). The other results from breathing O₂ at high concentrations at low pressure for a long time. The high O₂ irritates the lungs resulting in fluid build-up (potential for pneumonia). This is why patients on O₂ are taken off for short periods after 48 or 72 hr. exposures (if I remember the timeframes correctly). This is the limiting factor for underwater habitats in shallow water breathing straight air (Jules’ Underwater Habitat in ~33 fsw is limited to 72 hour stays). An early symptom of this is a tightness in the chest.

Dr. Bill Hamilton developed an inexact formula for keeping track of O₂ exposures at pressure as a guide. It is inexact as each person reacts differently to high O₂ exposures day to day.

R/J²

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

It is the mark of an educated mind to be able to entertain a thought without accepting it.
- Aristotle

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph Perkel
Sent: Sunday, January 28, 2007 11:28 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Perry lockout

Here is a link regarding 02 toxicity as applicable here. http://scuba-doc.com/o2tox.htm

I see the effects of 02 toxicity frequently in the ICU, (chronic obstructive pulmonary patients)...not a pretty picture. Different route of getting there but, same symptomatology.

Joe

From: Subscuba@aol.com
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Perry lockout
Date: Sun, 28 Jan 2007 10:40:27 EST

For what it's worth,

I had a close friend that got badly bent with a CNS hit. He was treated in a Hyperbaric chamber to 99 ft (pure O2) for 25 times. He should have been treated by Table 6 in a decent re compression chamber.He still has problems after 10 years.

I don't recommend a Hyperbaric chamber.

Ken Martindale

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