Sunday, May 6, 2012

Salt Water Aspiration and Scuba Diving

Thanks Natalie Gibb

As a scuba instructor, I tend to err on the side of over-caution. The dive equipment set-up and revision which I teach my students is very meticulous, and I insist that they perform these checks on every dive. One piece of equipment that I see many divers (and scuba instructors) overlook during their equipment set-up and inspection is the regulator mouthpiece. A mouthpiece's bite tabs may wear down or break off after many uses. Mouthpieces also tend to develop holes where the plastic tie-wrap holds them in to the regulator second stage. This is dangerous! Any mouthpiece developing holes must be replaced before diving. Holes in the mouthpiece can lead to salt water aspiration - a little-recognized syndrome that divers should know about.

Accidents happen. I observed an incidence of salt water aspiration (thankfully not on my dive!) at the beginning of my dive career. A diver ran low on air at the safety stop, and the instructor handed the diver his alternate air source regulator to allow the diver to breathe from his tank. All appeared well when the two surfaced and boarded the dive boat. The instructor had just launched into a lecture about the importance of carefully monitoring one's air supply underwater when the diver began to have difficulty breathing. He coughed, gasped for air, and felt weak. Suspecting decompression sickness, the instructor administered oxygen to the diver. When the boat reached the dock, and ambulance rushed the diver to the hyperbaric chamber.

The diver was not bent. He had inhaled a fine mist of salt water through a hole in the mouthpiece of the instructor's alternate air source regulator. The droplets of salt water were so fine that the diver didn't notice that he was inhaling anything other than air. When the dive gear was inspected, the hole discovered was so small that it was not visible unless the mouthpiece was pulled on and twisted. The diver, stressed from the low air situation, had pulled the hole open by looking around during the safety stop, and inhaled enough vaporized salt water to cause salt water aspiration syndrome. After treatment, the diver recovered and was perfectly fine.

What Is Salt Water Aspiration?:

Salt water aspiration may occur when a diver inhales tiny droplets of salt water due to an equipment malfunction or poor diving technique. Salt water aspiration may also occur in near drownings, or in any other scenario in which salt water is inhaled.

Salt water does all sorts of nasty things to a diver's lungs. One of the effects of inhaled salt water (without getting too technical) is that the high saltiness of the salt water in comparison to the relatively lower saltiness of the fluid in a diver's lung and body tissues causes body fluids to move through the walls of the divers' lungs (specifically the alveoli) and into his breathing spaces, making breathing difficult, if not impossible.

Symptoms of Salt Water Aspiration:

Salt water aspiration may be difficult to diagnose, because it mimics many of the symptoms of decompression illness. Some divers may have severe reactions to salt water aspiration (such as those with a history of asthma or hay fever) while others may have a much milder reaction. Symptoms are usually delayed from one to fifteen hours and may include the following:

difficulty breathing and chest pain
a cough that produces phlegm
flu-like symptoms including body aches, exhaustion, fever, nausea and headache
pale skin

What Is the Treatment for Salt Water Aspiration:

Most cases of salt water aspiration are mild, go undiagnosed, and resolve within a few hours. If a diver feels sick enough to suspect salt water aspiration, he should seek immediate emergency medical care. The symptoms of salt water aspiration mimic those of decompression sickness, and decompression sickness must be ruled out before salt water aspiration is diagnosed. Some of the treatments include administration of oxygen, rest, and administration of bronchial dilators. Treatment may also be required for infections caused by bacteria in the inhaled salt water. With treatment, even severe cases of salt water aspiration have a high chance of resolution.

How to Avoid Salt Water Aspiration When Scuba Diving:

Correct gear maintenance and diving procedures should prevent most cases of salt water aspiration. Check to make sure that your regulator mouthpieces have no holes. Be sure to stretch and pull the mouthpieces to ensure there are no hidden holes and check carefully around the margin of the mouthpiece where the tie-wrap holds it in place. Do this to both your primary and alternate air source.

More tips for safer diving:

• Why You Should Never Use the "Up" Button
• 8 Tips for Being a Safer, Better Buddy
• What Are No-Decompression Limits and Why Are They Important?

Check to make sure that the regulator's exhaust valves seal properly before diving. With the first stage dust cap in place, place the regulator in your mouth and inhale. If any air leaks in, the exhaust valve is not sealing properly, and will breathe "wet" when diving. Any regulator that leaks through the exhaust valve or breathes wet underwater requires maintenance.

Follow diving protocols that minimize the chance of water entering your mouth. Seal your lips well around the regulator mouthpiece, and be certain to block water from entering your mouth when using the regulator purge button. Exhale, or block the opening of the mouthpiece with your tongue when pushing the purge. Avoid removing the regulator underwater whenever possible, and refrain from flipping upside down or into unusual positions when diving. Most regulators will breathe a little wet when inverted.

The Take Home Message About Salt Water Aspiration and Scuba Diving:

Salt water aspiration is fairly uncommon in scuba divers, but it does occur. The condition may be difficult to diagnose because the symptoms mimic those of decompression illness. With this in mind, be sure to check your gear carefully before a dive (especially rental regulator mouthpieces), and follow procedures to prevent salt water from entering your regulator second stage.

Thanks to Natalie and

Kathy Dowsett

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