Dysbarism Treatment & Management

Updated: Jun 15, 2018
  • Author: Stephen A Pulley, DO, MS, FACOEP; Chief Editor: Joe Alcock, MD, MS  more...
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Prehospital Care

Extricate the patient from water and immobilize if trauma is suspected. Generally, in-water recompression is not believed to be a safe option. More is discussed about this in Decompression Sickness.

Administer 100% oxygen, intubate if necessary, and intravenously administer saline or lactated Ringer solution.

The use of first aid oxygen has proven so beneficial that the Divers Alert Network (DAN) has made a major effort to place oxygen at dive locations, in particular those that are remote with lengthy transport times to the nearest hyperbaric chambers, and to ensure that people are trained in its use. A study of the use of first aid oxygen found that the median time to its use after surfacing was 4 hours and 2.2 hours after the onset of decompression sickness (DCS) symptoms. Forty-seven percent of victims received the oxygen. Complete relief of symptoms was found in 14% of victims. Even more striking was that 51% of victims showed improvement. This was with the oxygen before hyperbaric oxygen (HBO) treatment. Even after a single HBO treatment, those that had received oxygen before the HBO dive, even if many hours earlier, had better outcomes. [97]

Aspirin is commonly considered and given in diving accidents for antiplatelet activity if the patient is not bleeding. However, there are no current data to support this practice. [98]

Perform cardiopulmonary resuscitation and advanced cardiac life support, if required. Needle decompression of the chest should be performed for tension pneumothorax if pneumoperitoneum is suspected.

Do not put patient into Trendelenburg position. Placing the patient in a head-down posture used to be considered a standard treatment of diving injuries to prevent cerebral gas embolization. This practice should be abandoned. The process actually increases intracranial pressure and exacerbates injury to the blood-brain barrier. [99] It also wastes time and complicates movement of the patient.

Transport to the nearest ED and hyperbaric facility, if feasible, and try to keep all diving gear with the diver. Diving gear may provide clues as to why the diver had trouble (eg, faulty air regulator, hose leak, carbon monoxide contamination of compressed air). The prolific use of diver computers can show details of the dive that can assist with the investigation.


Emergency Department Care

Administer 100% oxygen. Intubate if indicated.

Do not put the patient into the Trendelenburg position. Placing the patient into a head-down, Trendelenburg position previously was considered standard in the ED management of diving injuries to prevent cerebral gas embolization. Do not put patient into Trendelenburg position. This practice should be abandoned. The process actually increases intracranial pressure and exacerbates injury to the blood-brain barrier. [99] It also wastes time and complicates movement of the patient.

Intravenous fluids should be administered for rehydration until urinary output is 1-2 mL/kg/h.

Provide aggressive resuscitation, if required.

Aspirin is commonly considered and given in diving accidents for antiplatelet activity if the patient is not bleeding. However, there are no current data to support this practice. [98]

The patient should be treated for nausea, vomiting, pain, and headache.

Needle chest decompression and chest tube thoracostomy may be indicated to treat simple or tension pneumothorax.

Try to keep all diving gear with the diver.


Medical Care

Admission is rarely required for dysbarism issues. Pneumothorax, pneumomediastinum, pneumoperitoneum, or air embolism requires admission. Patients with signs of other dysbaric or decompression injuries require transfer to a facility with HBO capability.

For individuals with symptoms that are more than minimal, consult a diving medicine specialist or HBO specialist to determine appropriateness of treatment with HBO. Many times, dysbaric or other injuries can mimic decompression sickness and a diagnostic HBO treatment may be warranted to help determine this.

DAN is an excellent resource if local support is not available.

If HBO treatment is advised, an important issue is transport of the patient to the closest hyperbaric facility. This is frequently accomplished by land transport; however, air transportation is occasionally required. An effort should also be made to minimize the transport time.

Helicopter transport requires the pilot to maintain an altitude of less than 500 ft (152 m) above the departure point (which could be more than 500 ft above sea level depending on the dive location). [100] Flight paths through mountainous regions may make this difficult. In this situation, explore options other than rotary-wing transportation to the closest chamber. Fixed-wing transport should be limited to aircraft that can maintain cabin pressure at normal surface pressure of 1 atm (eg, Lear Jet, Cessna Citation, military C-130 Hercules).



Diving medicine or HBO specialists

Symptoms temporally related to diving indicate that consultation with a diving medicine or HBO specialist is needed.

The goal of this discussion is to determine the likelihood that symptoms are diving-related and the appropriateness of treatment with HBO therapy.


Urgent consultation with an ENT specialist may be useful.

The barotraumas of the middle and inner ears are caused by failure of the eustachian tube to release pressure. Early investigation into the use of natural or artificial eustachian tube surfactant shows promise as a potentially effective way to aid this process. [101]

Divers who experience inner ear DCS or barotrauma require detailed ENT diagnostic evaluation at follow-up. Most are asymptomatic but still have significant cochleovestibular deficits. [47] Inner ear barotrauma has a better short- and long-term outcome than inner ear DCS.

The specialist may often request sending the patient to the office. In such cases, consider inquiring about the ENT specialist's comfort with diving-related issues.

Divers Alert Network

Divers Alert Network (DAN) is an excellent resource, especially if local support is not available. Using this service should be considered similar to the use of a poison control center. It maintains a database of diving-related injuries and provides 24-hour-a-day consultative services including extent of injury assessment, recommendations for management, and referral to HBO therapy or local diving medicine specialists. Emergency contact 24 hours a day can be reached at the following numbers:

  • DAN World[wide] Emergency Number: +1-919-684-9111 (accepts collect calls)
  • DAN America Emergencies: +1-919-684-9111 (accepts collect calls); Nonemergency: +1-919-684-2948
  • DAN Brasil Emergencies: +1-919-684-9111 (accepts collect calls); Nonemergency: Do Brasil: Disque 0800 684 9111
  • DAN Europe Emergencies: +39-06-4211-8685
  • DAN Southern Africa Emergencies: 0800-020-111 (within South Africa); +27-11-254-1112 (outside South Africa, accepts collect calls)
  • DAN Japan Emergencies: +81-3-3812-4999
  • DAN Asia-Pacific Emergencies: DES Australia: 1800-088-200 (toll free within Australia — English only); +61-8-8212 9242 (from outside Australia-English only); DES New Zealand: 0800-4DES-111 (within New Zealand-English only); Korean Hotline: 010-4500-9113 (Korean and English)
  • Divers Alert Network


All patients treated for diving-related injuries should be instructed to not return to diving until they have consulted with a diving medicine specialist. The specialist will make a determination on the appropriateness of returning to the activity.

Dental prevention

To prevent issues related to dental exposure to pressure changes, it is important to have regular prophylactic dental examinations and care. For regular divers, it may be helpful to seek out dental professionals with specific expertise in diving-related dental issues. Methods exist to decrease the likelihood of these issues during dental work, but that discussion is beyond the scope of this article. Interested readers are referred to the References. [61, 62, 58, 63, 102, 103] During these examinations, periapical radiographs identify apical pathology. Pulp vitality testing (electric, hot, cold, laser Doppler flowmetry) assesses the health of the pulp nerves and blood supply. Prior restorations should be inspected for issues, including adjacent decay. If there is a need for addressing a carious tooth, care should be taken to identify involvement of the pulp chamber, and if present, sealing it appropriately. Root canal work, when exposed to pressure, can allow for penetration of air into subcutaneous tissues or the periradicular space. If there is deeper surgery adjacent to the maxillary sinuses, extra attention is required to ensure that there is no violation of the sinus structure. [58]

Restriction from diving should be considered after dental procedures to help prevent issues. Twenty-four hours was suggested for caries treatment requiring an injected anesthetic, 7 days for oral surgery, and at least 2 weeks if there is the potential of maxillary sinus violation. Additionally, it is recommended that people not dive with temporary restorations or other dental work in progress. Before lifting the restriction, the patient should be examined for complete healing related to the procedure. More restrictive restrictions are found in the Australian Defense Force, where any violation of the pulp chamber requires complete endodontic, root canal, treatment. [58]

If dental evaluation or procedures do not identify the cause of and relief of pain post dive, a nondental cause should be considered and appropriate referral made for a workup. Even in a confirmed dental cause for pain is not relieved by traditional means, hyperbaric therapy may be indicated.


Future prophylaxis with decongestants along with improved instruction may decrease recurrences. As mentioned above related to middle ear barotrauma, evidence of trauma to the tympanic membrane via otoscopy after a dive may guide prophylactic treatment to help prevent future middle ear barotrauma. [39] Many HBO centers use a topical vasoconstrictor nasal spray for this purpose (oxymetazoline). [104] However, studies have shown that there is minimal benefit to this approach, whereas predive treatment with oral pseudoephedrine (60 or 120 mg) at least 30 minutes prior to a dive decreased pain and evidence of tympanic membrane injury. [105, 106, 107]


The culture of diving, at least in military naval diving, may have some impact upon prevention of diving accidents. The two most common causes of diving accidents, or near misses, were leadership failures and decreased situational awareness. These came into play when the overall risk was underestimated and the time was not closely monitored. In addition, the need for junior divers to ask questions was rebuffed by the posture of the senior divers not being interested in providing answers. [108] While this was found in the US Navy, correlations could be considered in the average dive situation, namely daily dive charters. A lack of leadership, in the form of a divemaster, and the generally isolated situation of a number of divers not knowing each other, could lead to the same overall environment.


The first step in treatment of dysbarism is prevention. Long before the dive occurs, preparatory steps need to be taken. First, regular and recent dental examinations and timely, high-quality treatment of any issues uncovered are needed. The equipment being used should be reviewed. Ensure the regulator mouthpiece, mask, and weight belt fit properly. Prior diving history needs to be reviewed to identify any prior issues that might have been forgotten.

As the time of the dive draws near, a determination of fitness for diving needs to be made. Upper respiratory infection, sinusitis, serous otitis media, allergies, pulmonary diseases, cardiovascular disease, and external auditory canal obstruction (usually with cerumen) are all issues that could impair fitness for diving. Therefore, it is important that there be an examination by a healthcare professional, preferably one who understands the discipline and environment of SCUBA diving.

At the time of the dive, prophylactic medical recommendations should have been followed exactly as prescribed. These recommendations could include antihistamines, anti-inflammatories, vasoconstrictors, or decongestants for ENT issues or beta-agonists and inhaled steroids for pulmonary disease.

The last steps are equalization techniques to prevent squeeze or overpressurization of air containing cavities in the body. Most important is that the diver has selected specific techniques to use and has practiced them until they are second nature. There is even a recommendation to start gentle equalization techniques prior to the dive. If inflammation is impeding easy airflow into the middle ear or sinuses, the body can absorb the air inside the structure, creating a relative negative pressure and squeeze effect. Gentle equalization predive helps overcome this effect. The diver should prepare his or her mind for the techniques to be used and should consider that an issue may arise that will impede equalization and disqualify the diver that day.

The most pressure change for distance is at the beginning of the dive, in the first ATM (33 ft [10 m]) and especially in the first few feet of descent. The application of positive pressure to the middle ear, sinuses, and mask before submerging helps to compensate for the initial dramatic pressure change. "If the Eustachian tube is allowed to collapse at any time during descent due to squeeze, the pressure to re-inflate it becomes greater." [109] Dysbaric injury is more likely with rapid/uncontrolled descent or ascent. Therefore, proper buoyancy control is important. In addition, descent or ascent with a hand on a line helps with control of speed.


Yawn, swallow, chew

This is probably the most common technique for people who are flying. These techniques simply manipulate muscles to enhance opening of the eustachian tubes. It should be remembered that as one ascends above sea level, pressure change is more gradual as it takes greater distances for pressure changes. This is why this technique may be adequate. It does not apply positive pressure. Still, this works for some divers. Obviously, underwater, the yawn is modified as the lips need to maintain a seal on the regulator. The modified yawn can be enhanced by thrusting the jaw forward. An advantage of this technique is that no hands are required.

Valsalva maneuver

The Valsalva maneuver is the most common method used. Simply squeeze the nostrils (through the mask seal) together to prevent air from leaving through the nose, and then try to blow air out through the nose. This increases positive pressure in the nasopharynx, which forces air into the eustachian tubes and sinuses. To address mask squeeze, do not pinch the nose, allowing the air into the mask.

There are issues with this technique. First, it does not open the passages as does the yawn, swallow, or chew technique. If there was a delay in starting equalization, it can actually have the paradoxical effect of forcing the openings closed even tighter. Overpressurization can cause damage to the round window and tympanic membrane. This effect is more likely if there is unilateral obstruction. Extra efforts to open the blocked side can cause extreme overpressurization of the "normal" unblocked side.

The way to avoid this is to first equalize continuously during descent. Should there be difficulty equalizing, ascend to the point where the pressure is not felt, and try again. If this is not enough, temporarily occlude the external ear on the normal side by pushing the tragus inward. This maintains the same pressure in the external auditory canal and decreases tympanic membrane movement. Now the Valsalva maneuver can be attempted again. This tends to direct the pressure towards the blocked side. However, excessive pressure must be avoided. This can easily occur with increasing positive pressure and the sudden popping open, allowing all of the pressure to enter at once. While this technique decreases tympanic membrane motion, it does nothing to prevent overpressurization of the round window and the potential for rupture. If this does not clear the issue, the diver should return to the surface and cancel the dive.

Toynbee maneuver

This is a modification of the swallow. Squeeze the nares closed before swallowing. This encourages opening of the ostia while providing a small increase in pressure from the upward motion of the back of the tongue, rather than large pressures from the diaphragms on the lungs.

Lowry technique

Follow the instructions for Toynbee maneuver, and "blow" as you would with the Valsalva maneuver.

Edmonds technique

This is a modification of the yawn, with the addition of the nasal occlusion and Valsalva blow.

Frenzel maneuver

This technique is the hardest to understand and master. The diver squeezes the nares to occlude the nose as in the Valsalva maneuver. However, next the epiglottis is closed by initiating the first step of swallowing. The positive pressure is created by an upward thrust of the tongue while the pharynx opens. The diver should attempt to make a gurgling sound with the back of the tongue against the soft palate. This is the final position needed for the technique. For a more detailed description and instructions on how to practice the technique, see the reference. [110] One study recommends this technique to avoid injury to the eustachian tubes from overpressurization. [111]

The beginning and experienced diver should learn these various techniques and most likely use a combination of them during the same dive. It should be noted that techniques involving pinching of the nose will not work if the diver has Lester-Jones tubes used to treat lacrimal duct obstruction. This constantly patent tube would allow nasal pressure to escape to the eyes. [112]


Long-Term Monitoring

Consider reevaluation by an ENT specialist.

Complications of scuba diving should be discussed with a diving medicine or HBO specialist to determine appropriateness of returning to diving and strategies to decrease future occurrences.