Comprehensive information about diving and undersea medicine for the non-medical diver, the non-diving physician and the specialist.
Saltwater Aspiration Syndrome
You've just gotten home from a dive and you're feeling rotten. You ache all over, are so tired you can hardly hold your head up and you have a low grade fever, nausea, headache or shivering. You might even have some shortness of breath and a productive cough. You wonder if you might not have decompression symptoms.
Well, it might not be bronchitis or pneumonia from some creepie-crawlies in your regulator, but most likely salt water in your lungs that's to blame. First described by Dr.Carl Edmonds, this flu-like condition and short-term respiratory distress in divers occurs when even small amounts of micronized saltwater mist is inhaled into the lungs. Although not well-recognized, it's called saltwater aspiration syndrome and it can be avoided by taking several actions.
Interpolation of management would be similar to that given mildly affected cases of near-drowning. Most individuals are not this severely affected and never seek medical care. Others continue with severe cough and bronchospasm and require assistance. Patients with minimal symptoms (eg, coughing) and normal oxygen saturation should be observed for 24 hours; nearly all recover spontaneously within a few hours. In saltwater drownings and saltwater "wet" near-drownings (those that involve aspiration), the hypertonicity of the aspirated fluid draws intravascular fluid into the already fluid-filled alveoli, resulting in ventilation-perfusion abnormalities and intrapulmonary shunting. Intravascular hypovolemia, hemoconcentration, and electrolyte abnormalities can result, although this is not usually seen clinically in near-drowning survivors because they rarely aspirate enough water to produce these effects. It is doubtful that there is enough volume aspirated through a regulator to cause significant electrolyte abnormalities.
Divers who are alert but in respiratory distress require transfer to an intensive care setting for chest roentgenography, oxygen administration, and monitoring of oxygen saturation, arterial blood gases, urinary output, and electrolytes.
The initial chest film may be normal despite marked cough or respiratory distress. Since water ingestion and asphyxia can damage the alveolar capillary membrane, pulmonary edema can occur hours later as ARDS (Adult Respiratory Distress Syndrome). Frequent auscultation and continuous monitoring of oxygen saturation can detect this delayed complication.
Bronchospasm can be treated with inhaled beta agonists (bronchial dilators). In the rare person who proceeds to ARDS. continuous positive airway pressure, with or without mechanical ventilation, may be needed to maintain adequate PO2 and, accompanied by ventilation, is the single most effective treatment for hypoxemia.
Saltwater is hypertonic and can cause a shift of fluid from the circulation into the lung and pleural space, whereas freshwater is hypotonic to serum and is rapidly absorbed and redistributed. This might account for the productive cough associated with this syndrome and on a chronic basis could cause hemoconcentration, a known risk for decompression accidents. Ingestion of grossly contaminated water can cause pneumonia and lung abscess; fortunately these complications are rare.
It may be your regulator. Rodale's ScubaLab has tested some 185 models of regulators and has found a wide variation in the dryness of the equipment. They found that in general, all regulators will have a more difficult time staying dry when you are in odd positions (upside down, on your back, etc.) or just after you have replaced the regulator in your mouth, but top performers keep this to a minimum.
Get your regulator serviced on a regular basis. Some regulators breathe wetter due to the non-return exhaust valves not seating as well as they should. Proper maintenance can help prevent this. Rodale's offers this simple test: With no air pressure to the regulator and the first-stage dust cap firmly in place, exhale forcefully through the second stage and then inhale forcefully. You should get no air on the inhale. If your regulator doesn't pass the test, have it serviced before diving.
Keep your reg in your mouth as much as possible. The best way to keep your regulator breathing dry is to keep water out of the second stage. Use your power inflator, not your oral inflator, to minimize the number of times you remove your second stage from your mouth. Enter and exit the water with your reg in your mouth and use your regulator on the surface during rough water conditions. Do not buddy breathe to share air, but use an alternate air source.
Always exhale before you inhale on a regulator. If you are clearing a regulator in the water, take your first breath cautiously. If any water remains in the second stage, tilt your head so the exhaust is at the lowest point, helping to drain the rest of the water out. The best method for clearing a regulator: put the second stage in your mouth, tilt your head so the exhaust is at the lowest point, then exhale while gently pushing the purge button.
Keep your mouth shut. Even if your regulator
working properly, you will inhale a saltwater mist if you do not keep
mouth firmly sealed around the mouthpiece.
Ernest Campbell, MD, FACS All Rights Reserved.