Management of Diving Injuries

James Chimiak

Peter Buzzacott

INTRODUCTION

Diving medical emergencies are among the most rewarding calls to which emergency medical services (EMS) personnel are summoned. The responder must employ physics, human physiology, anatomy, the activity involved, past medical history, underwater breathing equipment, and the environment both above and below the surface to care for their patient. Each of these key elements will provide the necessary information when considered together to create a working diagnosis and effective intervention.

DEFINITIONS

The topic of this chapter is compressed air underwater diving. This is not to be confused with diving into a pool or cliff diving. This chapter will discuss in detail the problems that arise from individuals breathing compressed gas (usually air) underwater. An individual utilizing this technology to breathe while underwater will be termed a “diver” in this chapter.

A brief mention of breath hold diving will also be included, and they will be referred to specifically as “breath hold divers.” Divers breathing compressed air underwater are distinctly different than those divers holding their breath to get below the water surface. In the not so distant past, excellent health and fitness was a requirement to be a diver. So, when such a diver presented with a dramatic life or limb threatening problem, it was usually a dive related problem. But, today the popularity of the sport has also attracted those with increasing age and significant medical conditions to become divers. Well conducted diving history and physical examinations are now especially important to identify and outline the risks of diving tailored to each patient. Conditions such as asthma, diabetes, patent foramen ovale (PFO), and heart disease are examples that require detailed discussion.¹

SCOPE OF DISCUSSION

Some of the most important steps in the care of diving-related injuries are field-based interventions. EMS personnel can be the primary medical professionals responsible for stabilizing or even reversing the pathologic process. These early measures can improve the overall outcome even if emergent recompression therapy is needed. A background into the environment and pathophysiology will make these conditions more easily understood, and will help make the measures recommended understandable in terms of reasonable medical sense to the responder.² This section will also identify specific environments that may share similar pathophysiology to compressed air diving, such as iatrogenic air embolism or passenger egress from an air pocket in a submerged vehicle. The WEMS provider may be the only one to recognize early and include these life-threatening causes in the differential during on-scene care. Lastly, there can be significant interactions between diving injuries and a patient’s underlying medical condition. The number of such considerations is beyond the scope of this chapter but is important to consider, including seeking additional guidance from medical oversight, especially with patients who have known underlying chronic medical conditions.

Manned underwater activity is almost as old as humankind itself. From simple breath hold diving to deep commercial saturation diving, the desire to work productively has driven humans to innovate and develop means to continue to breathe underwater. Breathing compressed gas has become the most efficient way for humans to conduct useful work while he is underwater.

As with most advanced technologies, militaries have adapted and even developed better technologies to improve human performance underwater. Commercial interests, especially to support offshore oil production, have also adapted and further improved diving techniques. However, the most explosive growth in diving populations has been in recreational diving. It is also the most challenging group, mainly because these divers are the most diverse. They come in all sizes, ages, fitness levels, experience, motivation, gender, training level, and health status. This is in stark contrast to military and commercial divers, who are a relatively homogeneous group in comparison. In addition, professional divers generally will have medical support that is often quite impressive. In fact, it would not be unusual and often the requirement for professional divers to have recompression chamber capability and medical support at the dive site with a diving medical physician involved in all phases of the dive. So, this chapter will be primarily devoted to the emergency response to the injured recreational diver who arguably poses the greatest challenge to manage.

The chapter will explain the physics associated with diving. It will explain the environment and the interaction with the diver’s physiology. Specific injuries will be explained, the approach to differentiate one from the other, and the definitive treatment measures to implement. Special considerations during transport and description of the treatment to be rendered when delivered to a facility for definitive care will be discussed. The basic principles for the evaluation and management for the recreational diver should be applicable to management of any diving injury, and exceptions to this principle will be illustrated.

EPIDEMIOLOGY

In 2015, there was an estimated 3,000,000 scuba divers in the United States with ˜1,400 Americans presenting at the emergency department (ED) for dive injuries annually. Many more injuries do not result in ED presentations. At various locations and times, among various diving groups, using methods from self-reporting to hospital diagnosis, overall diving injury rates have been reported as high as 13 per 20,000 dives. The frequency of ED presentations for dive injuries is thought to be around 1 per 20,000 dives, with 50 to 60 recreational dive fatalities per year in the United States. In the United States, it is estimated there are two dive-related deaths per hundred thousand recreational divers per year, or an incidence of two deaths per million recreational scuba dives.³

The following will discuss the clinical management of diving-related injuries and illnesses. There were 146 recreational diving and 35 breath hold diving deaths in 2015 worldwide. However, it is important to remember that routine medical conditions (discussed in Chapter 22) can also occur in the diving environment, and can be a significant source of morbidity and mortality. For example, the leading known cause of diving deaths in divers over 40 is cardiac related, not any specific diving illness. This may have some part in the fact that male and female divers over 40 years of age accounted for 84% and 69% of all 2010 to 2013 U.S. and Canadian diving fatalities, respectively. Overweight and obese divers account for 80% of fatalities.³

CLINICAL MANAGEMENT

The clinical management of diving injuries will include a brief description of the physics involved, merely to serve as a refresher for previous physics and chemistry instruction. A more in-depth discussion of the pathophysiology will then be followed by treatment. Each section dealing with a specific diving injury will be followed by methods of prevention. It is convenient to think of most diving injuries as those resulting from barotrauma and those occurring because of dissolved gases/decompression injury.

Barotrauma

Barotrauma is essentially tissue trauma that results from unequal pressures acting on sensitive structures in the body. These injuries can range from a slight ear discomfort to gas escaping into the cerebral arteries and causing dramatic life-threatening problems (Figure 17.1).

Physics: The relationship between gas volume and pressure is described by Boyle’s law. It states that the pressure of a gas is inversely proportional to its volume. It is often written as:

P_i × V_i = P_f × V_f

where the product of the initial volume (V_i) and initial pressure (P_i) equals the product of the final pressure (P_f) and volume (V_f). One can see that if the pressure decreases, then volume must increase (Figure 17.2).

This can best be seen when a balloon is inflated underwater. As it ascends and the ambient pressure lessens, the volume increases, and the balloon may even burst before it reaches the surface.

This may occur while diving if a deep breath of compressed gas is taken at depth and then an ascent occurs while the breath is held. The lungs rupture and release gas into the tissue.

The effects of Boyle’s law are responsible for the barotrauma that can affect various parts of the body, such as skin, sinuses, eye, middle ear, dental caries (cavities), lungs, and intestines. This trauma can either be due to a positive or negative relative pressure gradient exposure to a given body tissue. If that air space is at a pressure lower than the surrounding environment, then a relative vacuum is created. This is known as a squeeze. This effect normally occurs when descending, where the trapped gas at ambient or surface atmospheric pressure is surrounded by ever-increasing pressure that occurs with descent. It has been said that nature abhors a vacuum and delivers that message clearly to divers if allowed to occur. The body will attempt to fill that

space with swollen tissue, serous fluid, and even blood. On ascent from depth, if gas is trapped in an air space at that increased pressure and cannot be vented, then that space will expand or even burst as the trapped gas pressure continues to expand. This is known as a reverse squeeze. Barotrauma injures various organs in characteristic ways, which will now be detailed individually.

FIGURE 17.1. Barotrauma to the lungs can result in pulmonary overinflation syndrome (POIS) with cerebral air embolism, subcutaneous emphysema, pneumomediastinum, and pneumothorax possible. Courtesy of Rick Melvin and DAN, Divers Alert Network, Inc.

FIGURE 17.2. Pressure-Volume Relationship of Gas. The same gas exposed to half the absolute ambient pressure will occupy twice the volume. Courtesy of Rick Melvin and DAN, Divers Alert Network, Inc.

Skin Barotrauma

Barotrauma can happen to the skin. This is commonly called “suit squeeze” and can occur in dry suits where air fills the space between the suit and the skin. If a pocket of dry suit material is in tight contact with the skin and unable to equalize with ambient pressure, a relative negative pressure may form. The underlying skin is variably affected. The diver may be able to relate a squeezing or pinching sensation on descent with unusually shaped bruising where this occurred.

This requires no intervention. It needs to be differentiated from cutaneous decompression sickness (DCS), which usually occurs later after the end of the dive rather than initially on descent.

Air trapped below the skin during pulmonary overinflation syndrome (POIS), known as subcutaneous emphysema, may expand with ascent and become easily palpable as crepitus.

Sinus Barotrauma

The sinuses are air-filled spaces that are situated throughout the skull. These air-filled spaces communicate with ambient pressure via small openings, also known as ostia. These small openings, like the sinuses, are lined by mucous cells which are susceptible to blockage from mucosal swelling or copious mucous production, especially following persistent attempts at descent or if there is difficulty equalizing pressures between compartments. Severe pain may ensue as well as noticeable amount of blood via the nose. Blood may also be seen with coughing since blood from the sinuses can drain into the back of the throat.

FIGURE 17.3. Outer, middle, and inner ear. Inadequate equalization of the outer or middle ear can result in barotrauma. The extremely important inner ear functions of balance and hearing can also be injured because of barotrauma. Courtesy of Rick Melvin and DAN, Divers Alert Network, Inc.

Ear Barotrauma

The ear is the most common site of injury caused by barotrauma and is the most common diving injury overall. The ear is divided into the outer (or ear canal), middle, and inner ear (Figure 17.3).

These regions can be injured by barotrauma. The outer ear canal can become a closed air space if the external meatus is occluded by ear plugs, tight-fitting hood, or even cerumen. On otoscopic examination, the canal itself may be inflamed and the tympanic membrane erythematous. This must be differentiated from acute otitis externa (AOE)—AOE will often have an exudate present due to infection.

The middle ear is a closed air space except that it relies on the Eustachian tube to ensure the space is equalized to ambient pressures. If this tube is obstructed by mucous, congestion, or other materials, the middle ear will not equalize properly.⁴ The tympanic membrane will be drawn into the space and may drive the footplate of the stapes, into the inner ear, causing injury to the organ that affects hearing and balance. Blood and fluid may also fill the space in attempts to alleviate the relative vacuum created. Otoscopic examination will reveal erythema, hemorrhage, and even perforation of the tympanic membrane.

Treatment of tympanic membrane injury is usually supportive. Certainly, no further diving should be undertaken until the condition is resolved. Avoid changes in ambient pressure that can further traumatize the ear. A decongestant may help open the Eustachian tube and vent the middle ear space.

Injury to the inner ear will manifest as vertigo and hearing loss. Injuries to the inner ear must be differentiated from inner ear DCS (which will be discussed later) because the treatment
is very different. Barotrauma will normally occur on descent or upon reaching the bottom. There is usually a history of difficulty equalizing the middle ear and evidence of trauma to the middle ear may be evident on otoscopy, while inner ear DCS will normally occur just after surfacing and may be associated with other neurologic abnormalities. Treatment for inner ear barotrauma includes placing in position of comfort and transporting to a medical center.⁵ An ENT surgeon may later be required for the repair of the rupture to either the round or oval window resulting in a perilymph fistula in order to correct debilitating vertigo or hearing loss.

Dental Barotrauma

Poor dentition can result in spaces in the tooth that trap air. On descent, this may cause some discomfort, and will eventually resolve as air slowly equilibrates with that space. On ascent, this air may not be able to escape quickly enough resulting in discomfort again, but the pressure may increase to the point that the decayed tooth may fracture. Supportive measures for dental injury may be required. The differential includes reverse barotrauma to the maxillary sinus that may cause pain on ascent when pressure builds in the sinus, in which case pain may be referred to the upper teeth.

Lung Barotrauma

The lung may also be affected by unequal pressure differential between the air-containing sacs known as alveoli and the ambient pressure. In fact, the mechanics of the lung utilizes pressure differentials for inhalation and exhalation required for ventilation. POIS may occur when air is trapped in the lungs and ascent to the surface is performed without allowing that air to escape freely. This commonly occurs when a diver holds his breath on ascent to the surface. The trapped air expands in accordance with Boyle’s law, overinflating the alveoli and lung injury may occur. This results in a variety of conditions grouped together as POIS. When the lung ruptures, the escaping air moves to various locations. It is by these locations that the subgroups of POIS are named. Multiple subgroups may occur when a case of POIS is encountered.

Subcutaneous emphysema occurs when the air escapes into the soft tissue and skin. Crepitus (snap, crackle, and pop sensation felt with palpation of the skin) is characteristic. It is often found around the upper chest, neck, and even around the head. Moderate neck pain may be experienced. This condition usually requires only surface level oxygen administration; serial ongoing evaluation of the respiratory and nervous system is recommended to rule out more serious associated injuries discussed later in this section.

Mediastinal emphysema manifests as air in the mediastinum, including around the heart. Chest pain, which can be seen in other serious medical conditions as well, is often noted in POIS, perhaps as result of lung stretch receptor stimulation or trauma to the tissues affected by the escaping, expanding air mass. Voice change might be noticed because of the air tracking into the neck. This usually requires oxygen administration and again ongoing evaluation of the lung and nervous system.

Pneumothorax can be a manifestation of POIS. The ruptured lung may allow air to escape and collect between the lung and chest cavity. If it occurred while ascending, the air may further expand or a situation where air continues to escape from the lung but cannot return from this expanding space. This results in a tension pneumothorax, a life-threatening emergency. Critical cardiopulmonary impairment can result if this situation is not reversed quickly. Shock, dyspnea, tracheal deviation to the contralateral side as well as absent breath sounds and tympanic percussion are found on the affected side in the case of tension pneumothorax. Needle placement or a definitive treatment with a chest tube may be indicated emergently. These interventions are discussed in a WEMS context within Chapter 21 (Trauma Management).

Arterial gas embolism (AGE) may develop from air escaping from the alveoli and entering the pulmonary blood vessels.⁶ The air, in the form of a bubble, can then travel and lodge in distal vascular structures supplying vital organs and block blood flow to these areas. The central nervous system (CNS) is vulnerable to this insult and demonstrates rapid, dramatic neurologic deficits minutes after the POIS episode.⁷ Symptoms can include numbness, weakness, dizziness, extreme fatigue, hearing changes, tremors, chest pain, mental status changes, lack of coordination, nausea/vomiting, bloody sputum, and paralysis. Convulsion, loss of consciousness, arrest, and even death can occur. Often the disabled diver reaches the surface and is unable to swim to safety, sinks, and subsequently drowns.

Lung overinflation or POIS should be suspected in anyone who makes a rapid ascent and may have inadequately exhaled while ascending to the surface.⁸ Evidence of any of the above symptoms for any of the subgroups should warrant⁹:

1. removal of the patient from the water and placement in supine or seating position

2. airway and breathing assessment; supplemental oxygen administration

3. if indicated, needle placement to treat a tension pneumothorax

4. evaluation of lungs and trachea and then chest, neck

5. careful neurologic examination

6. evacuation to ED for additional testing that may include lung imaging

POIS is often seen in novice divers who may have panicked for a number of reasons while underwater or during initial training. Even experienced divers can incur this injury, especially when their air supply is suddenly interrupted and they bolt to the surface. In addition, certain medical conditions such as asthma
have been implicated in POIS. It is thought that the narrowed, mucous-filled, reactive airway may impede airflow and allow the lung to overinflate during ascent.

The first responder should always be alert to POIS for anyone, not just scuba divers, who may have breathed compressed air. Such individuals include non-divers who might have been swimming underwater and breathing from an air pocket underwater or from a friend’s regulator and then held their breath while swimming to the surface. As perplexing to a first responder would be the patient egressing from a submerged vehicle accident who takes one last deep breath from the compressed air pocket inside the vehicle (by Boyle’s law that air has been compressed to the depth of the vehicle) before holding his breath and making it to the surface. The patient may have been seen at the surface before sinking back to depth or collapsing upon reaching the shore. Cardiopulmonary or neurologic difficulties may be something seen when called to care for such a patient at the scene.

A reverse squeeze can occur when the pressure in the lung is less than the ambient pressure. This occurs predominantly in breath hold free divers. These divers do not use scuba or compressed gas while diving. Instead, they hold their breath. The depth limitation is determined not just by the limit of their ability to hold their breath, but also at the point where the relative negative pressure causes lung trauma that results in fluid and even blood leak into the air spaces. Loss of consciousness can ensue if not addressed promptly. If the diver is successfully rescued, aggressive measures to maintain breathing and airway may be required before evacuation to the nearest ED.

Gastrointestinal Barotrauma

The gastrointestinal (GI) tract can be affected by Boyle’s law. Barotrauma on descent is not likely, since any gas trapped in the GI tract will be compressed by the nonrigid structure of the bowel. However, on ascent, any compressible gas will expand and normally will be safely expelled at either the entry or exit orifices to the GI tract. If there is obstruction that blocks this expulsion, GI tract rupture could occur. Fortunately, this is an extremely rare event.

Decompression Illness

This section deals with both DCS and AGE. Decompression illness (DCI) is the term that includes either DCS or AGE.¹⁰ Both conditions involve the pathologic effects of bubbles that can occur when scuba diving.

Both DCS and AGE can occur at the same time. This is usually the consequence of a rapid, often uncontrolled ascent from a deep long dive. They are difficult to manage and have been termed type III DCS. Fortunately, it is not often seen since the management can be quite challenging.¹¹ The symptoms and the requirement for prompt recompression in a hyperbaric oxygen chamber bear close similarities, so it is convenient for emergency personnel to use the term DCI to manage these patients.

However, there are some significant differences between AGE and DCS. DCS is also called the bends. It may have received this name because severe cases can result in abdominal pain causing the victim to bend forward in an attempt to achieve some relief. So, someone suffering from DCS might be referred to you by his dive team as “being bent.”

AGE was discussed in some detail in the POIS section earlier. It can be a dramatic presentation ranging from paresthesia to loss of consciousness shortly upon reaching the surface. It can occur in depths as shallow as 4 to 5 ft of water and with little or no time at depth. DCS incidence and severity has a positive correlation with increasing depth and time of a given dive. AGE presents within minutes following a dive while DCS may require more time to evolve. Most DCS cases present within a few hours of surfacing, with nearly all appearing within 24 hours. The U.S. Navy reports that 42%, 60%, 83%, and 98% of symptoms occurred within 1, 3, 8 and 24 hours following a dive, respectively (Figure 17.4).¹²

DCS is attributable to the imbalance between the limit of inert gas (nitrogen) that can safely remain dissolved in tissue (including blood) and the actual amount of gas in those same tissues.¹³ Keeping gas in solution and from shifting to the harmful gas phase is what dive tables and dive computers determine. They limit a diver’s time and depth to limit the risk of DCS. Henry’s law describes the fact that the amount of dissolved gas is proportional to the pressure that gas exerts over that substance. Think of a warm bottle of cola. If opened abruptly, the gas in solution will come out of the solution violently and bubble out of the top. But if opened very slowly to allow the gas to slowly escape and allow gas to gently transition to the surface and out of the bottle, this violent display is averted.

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