Prehospital Care
Prehospital care should consist of assessing the ABCs and correcting any immediate life-threatening conditions while maintaining adequate oxygenation and perfusion. Patients should be placed on high-flow oxygen and have large-bore venous access with isotonic fluid infusion to maintain blood pressure and pulse. Although research is being done on the use of surfactants being given prior to high-risk activities such as deep dives or space missions, it is still in the bench research stage of development. [37] Several in vitro studies have been promising, and there is hope that surfactant use will someday greatly decrease the frequency of barotrauma.
Emergency Department Care
Stabilize the airway, breathing, and circulation.
Intubation
Perform endotracheal intubation on a patient who has an unstable airway or has persistent hypoxia despite breathing 100% oxygen. If tension pneumothorax is present, decompress chest prior to intubatiuon unless in respiratory arrest.
Perform tube thoracostomy to evacuate a pneumothorax or hemothorax.
Perform nasotracheal or orotracheal intubation when appropriate.
Needle decompression
Needle decompression of the chest is indicated for suspected tension pneumothorax. A large-bore needle is inserted over the rib in the 5th intercostal space, anterior axillary line.
Foley catheterization
Place a Foley catheter in patients who present with shock to assist in assessing volume and hydration status. Normal urine output is 1 mL/kg of body weight per hour.
Place a Foley catheter in patients with spinal cord manifestations of DCS who are unable to void due to a neurogenic bladder.
Hydration
Continue intravenous hydration to maintain adequate blood pressure.
Recompression therapy
Recompression therapy should be performed at a dive chamber by a dive medical officer or personnel certified in hyperbaric medicine. Indications include spinal cord injury and neurologic impairment.
Sinus squeeze
Symptomatic therapy with decongestants, both oral and nasal, is indicated.
Pain control should be instituted with nonsteroidal anti-inflammatory drugs (NSAIDs) or narcotic analgesic medications.
Middle ear squeeze
Severity and treatment are based on the Teed scale, as follows:
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Mild (Teed 0-2): Decongestants, both nasal (0.05% oxymetazoline hydrochloride spray bid for 3 d) and oral (pseudoephedrine 60-120 mg bid/qid) are administered.
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Moderate (Teed 3-4): Treatment is same as above, but a short course of oral steroids, such as prednisone 60 mg/d for 6 days then tapering over 7-10 days, may be needed. If TM has ruptured or water is contaminated, consider antibiotics that treat acute otitis media.
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Severe (Teed 5): Treatment is same as above. Consider myringotomy if the above have failed. Control pain with Tylenol with codeine (acetaminophen 300 mg with codeine phosphate 30 mg) 1-2 tablets every 4-6 hours.
Decompression sickness type I
These patients should receive high-flow oxygen via a nonrebreather mask.
After establishing intravenous access, administer isotonic fluids (isotonic sodium chloride solution or lactated Ringer solution) to maintain urine output at 1-2 mL/kg/h.
These patients should also receive aspirin 325-650 mg for antiplatelet effects as well as pain control.
Obtain appropriate radiographs to evaluate for fractures or dislocations.
If a patient's medical condition continues to deteriorate, he or she is then classified as having DCS type II.
Currently, the United States Air Force is developing a new, shorter Treatment Table 8 (TT8) that allows for dives of shorter duration (lasting 30 min with air breaks between each 2 atmospheric absolute [ATA] dive). This is done with 4 dives each for 30 minutes with 10-minute air breaks. The TT8 should only be used to treat DCS type I when symptoms occur within 2 hours of altitude chamber or flight and when partial response on oxygen after 10 minutes has occurred. Treatment Table 6 (TT6) should be used immediately if symptoms persist after the first 30-minute interval or recur within 24 hours.
Decompression sickness type II
All of the interventions for DCS type I are appropriate for DCS type II.
These patients need recompression therapy to resolve their symptoms.
The most appropriate management is to transfer the patient to the nearest hyperbaric chamber.
Arterial gas embolism (AGE)
Patients with AGE can have mild symptoms from a small embolism that may improve with therapy for DCS type I, including intravenous hydration, high-flow oxygen, and aspirin.
Patients with severe AGE (ie, unstable blood pressure, respirations, neurologic status) require immediate recompression therapy in a hyperbaric chamber.
Medical Care
Further inpatient care
Patients may require multiple recompression "dives" in a hyperbaric oxygen chamber to reverse neurologic impairment or to treat air emboli.
Patients with continued pain despite appropriate treatment at sea level require recompression.
Patients who are seriously ill or do not respond to initial treatment may require higher pressure recompressions at 4-5 atm of absolute pressure and may need breathing gas of 50% helium/50% oxygen mixture (heliox).
No definitive studies have proven that other modalities provide increased long-term benefit.
Transfer
Patients with DCS type II or severe AGE should be transferred to a recompression chamber. The chamber specialist must be contacted prior to any transfer to determine availability. When presenting the case, the dive medical officer needs to know the following signs and symptoms:
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Vital signs
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Pertinent medical symptoms (especially neurologic)
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Time last dive finished
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Onset of symptoms
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Length of dive
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Depth of dive
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Decompression stops (length of time and depth)
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Any flight or change in altitude after dive
If the patient is to be transferred by air, the aircraft must stay below 1000 ft if possible, depending on the terrain, or be transported in a pressurized aircraft. Flight crew must be aware of the patient's condition to assist the pilot in keeping the aircraft fully pressurized before attaining altitude.
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Basic US Navy dive table used to compare the patient's dive profile to the standard dive profile. Reprinted with permission of the US Navy.
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US Navy dive table for altitude diving used to compare the patient's dive profile with the standard dive profile at altitude. Reprinted with permission of the US Navy.
