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Authors:
Joshua Goldstein, MSIII Medical Student
University of Miami Miller SOM
Tim Montrief, MD MPH
Jackson Memorial Health System/University of Miami
AAEM/RSA Publications and Social Media Committee Member
Introduction
SCUBA (Self Contained Underwater Breathing Apparatus) Diving is becoming increasingly popular, with an estimated 306 million dives made in the United States between 2006 and 2015.[1] During that same time there were 658 diving deaths in the United States and nearly 14,000 emergency department (ED) visits.[1] While the pathophysiology underlying many diving injuries is complex, the basic treatments for many life-threatening diving injuries are the same (Figure 1). It is important to understand the relatively simple therapies that underlie appropriate care for these injuries.[2,3]
Pathophysiology
The underlying pathophysiologic process of nearly all diving is the compression or expansion of trapped gasses within the human body. Injuries can be further subdivided into either barotraumatic injuries or decompression illness (DCI). Barotrauma refers to tissue damage which occurs when a gas filled cavity rapidly changes volume, most commonly affecting the respiratory system as well as the air-filled portions of the ear.[2]
DCI, on the other hand, is caused by dissolved gasses forming trapped bubbles within the tissues. When a diver breathes compressed air at depth, the partial pressures of gasses dissolved in the blood and tissues increases. Under normal conditions, a diver ascends slowly, allowing the dissolved gasses to diffuse from the tissues and escape via exhalation. However, in the case of rapid ascent, the trapped gasses expand, forming bubbles throughout the body, most commonly the large joints.[3]
Considerations in the History, Physical Exam, and Initial Investigations
Diagnosis of SCUBA diving injuries is primarily clinical, based on characteristic findings during the history and physical exam. The chief complaint will typically indicate the organ system involved and specific care must be taken to specify the timing of symptom onset (i.e. descent, ascent, or after ascent). Important historical considerations include dive information (i.e. depth), type of gas used, recent travel, trauma, or stings during the dive, as well as past medical history including lung and neurological diseases. A focused physical exam should always include careful auscultation of the lungs and a thorough neurological exam. While labs and imaging are not always necessary to confirm the diagnosis, they are recommended for all patients with suspected decompression illness or cardiopulmonary symptoms.[2] Initial investigations may include a chest x-ray, electrocardiogram, complete blood count, cardiac enzymes, and serum electrolytes.[2]
Management Pearls
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| Figure 1. Management of SCUBA diving injuries algorithm |
All Patients
The Diver Alert Network (DAN) operates a 24/7 expert hotline for health care workers, and should be contacted for specific advice whenever a diver with a serious injury presents in the ED. The number is +1-919-684-9111.
Ear Barotrauma
Ear complaints occur during descent and are the most common disorder experienced among divers.[2] Patients may present with pain, tinnitus, hearing loss, vertigo, or facial nerve palsy. It is imperative to differentiate inner ear barotrauma from middle or outer ear barotrauma.[2]
Inner ear barotrauma occurs with rupture of the round or oval windows, and results in sensorineural hearing loss with profound vertigo. A Weber test (tuning fork in the middle of the forehead) will be quieter on the affected side. A Rinne Test (tuning fork held next to the pinna then touching affected mastoid bone) will show equally diminished sound conduction via bone and air, indicating sensorineural hearing loss. Inner ear barotrauma can result in permanent hearing loss secondary to structural damage to the cochleovestibular system and thus requires urgent ENT evaluation.[2,4]
By contrast, isolated middle or outer ear barotrauma is not a medical emergency. These can be diagnosed with simple otoscopic evaluation – middle ear barotrauma will present with an erythematous or ruptured tympanic membrane with conductive hearing loss, while outer ear barotrauma is characterized by petechiae in the ear canal without hearing loss. The treatment for both is analgesia and urgent outpatient follow-up with a primary physician.[2,4] In the case of a ruptured tympanic membrane, ciprofloxacin 0.2% auricular solution can be used to prevent infection.
Decompression Illness (DCI)
Symptoms of DCI develop soon after ascent, often within one hour and almost always within the first 24 hours.[3] Most commonly (68% of cases), bubbles emerge within the connective tissues of the joints, causing deep, aching pain, colloquially known as “The Bends.”[2,3] Numbness and paresthesias are the 2nd most common initial symptom (27% of cases). Other manifestations can include loss of consciousness, vertigo, seizure, or stroke-like symptoms.[3] The treatment for all DCI is identical: 100% oxygen, isotonic saline boluses, and recompression.[2,3] If no hyperbaric chamber is available, patients should be transferred to a capable site as soon as they are hemodynamically stable. A full workup is recommended, but should never delay recompression.[2,3]
Pulmonary Complaints
Pulmonary barotrauma, the most severe form of barotrauma experienced by divers, includes pneumothorax, pneumomediastinum, and arterial gas embolism (AGE). Symptoms present during or immediately following ascent, especially a rapid emergency ascent. Patients with pneumothorax have decreased breath sounds with hyperresonance on the affected side and may develop respiratory distress with hemodynamic compromise. Management includes observation, oxygen, needle aspiration, or chest tube placement based on severity. Tension pneumothorax, with respiratory distress, tracheal deviation, and hypotension, may also develop. These patients require emergent needle decompression followed by chest tube placement.[2,5]
Pneumomediastinum generally presents with chest pain and subcutaneous emphysema (palpable air under the skin) of the neck and chest. It can most often be diagnosed with a chest x-ray. The condition is typically benign and self-limited; however, clinicians must carefully evaluate these patients to rule out more serious conditions including air embolism and pneumothorax.[2]
AGE is one of the most serious complications of pulmonary barotrauma. Ruptured airways allow gas to enter the pulmonary circulation, return to the heart, and migrate to the rest of the body causing a variety of ischemic symptoms, including strokes and myocardial infarctions. Symptom onset is during or immediately following ascent. The neurologic and cardiac manifestations of DCI are indistinguishable from AGE, and thus are treated identically: 100% oxygen, recompression, and urgent contact of the DAN hotline.[2, 3, 6]
Contamination and Toxic Effects of Inhaled Gasses
Diving at extreme depths or using specialized air mixtures can result in complications associated with high partial-pressures of inhaled gasses. Nitrogen, which is inert at sea-level, can exert a narcotic-like effect when divers journey below 30 meters. At high concentrations, oxygen and carbon dioxide become toxic, resulting in altered mental status and seizures. While dangerous at depth, these effects resolve quickly upon ascent and breathing of room air. No treatment is needed in the ED. Contact DAN for situation-specifics recommendations.[2]
Carbon Monoxide is a feared toxin often associated with space heaters and car engines, however, in the case of faulty compression equipment, contamination of diver’s air tanks is possible. Patients will typically follow carbon monoxide’s characteristic presentation. All divers presenting with persistent altered mental status should be evaluated with a pulse oximeter capable of differentiating carboxyhemoglobin if carbon monoxide poisoning is suspected. High flow oxygen via non-rebreather mask is the initial treatment of choice, with hyperbaric oxygen as the definitive therapy.[2,6]
Conclusion
SCUBA diving remains a popular sport worldwide, and patients continue to present to the ED following diving accidents. The most common issues include barotrauma of the lungs and ears, AGE, and DCI. Important considerations include chief complaint, history of the dive, and timing of symptom onset. Physical exam should focus on the organ system affected, with careful attention paid to the pulmonary and neurological exams. Findings concerning for AGE or DCI should prompt immediate recompression along with administration of isotonic saline and 100% oxygen. Lastly, DAN should be contacted for situation specific advice whenever a diver with a serious injury presents in the ED.
References
1) Buzzacott P, Schiller D, Crain J, Denoble PJ. Epidemiology of morbidity and mortality in US and Canadian recreational scuba diving. Public Health. 2018;155:62-68.
2) Degorordo A, Vallejo-manzur F, Chanin K, Varon J. Diving emergencies. Resuscitation. 2003;59(2):171-80.
3) Vann RD, Butler FK, Mitchell SJ, Moon RE. Decompression illness. Lancet. 2011;377(9760):153-64.
4) Elliott EJ, Smart DR. The assessment and management of inner ear barotrauma in divers and recommendations for returning to diving. Diving Hyperb Med. 2014;44(4):208-22.
5) Sahn SA, Heffner JE. Spontaneous pneumothorax. N Engl J Med. 2000;342(12):868-74.
6) Moon RE. Treatment of diving emergencies. Crit Care Clin. 1999;15(2):429-56.
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