Wednesday, March 29, 2006

Problems, Divers With Disabilities

We get fairly frequent requests for information concerning diving with various disabling conditions and have generally applied the knowledge known to exist for all divers to the limitations of the particular disability involved. This has in most cases been satisfactory but occasionally we run into a wall of lack of pertinent information, such as the effect of pressure on electronic implants and pumps. Cheng and Diamond published a review of potential problems that they recognized as being important to divers with disabilities in the American Journal of Physical Medicine and Rehabilitation in May of 2005 and the article is paraphrased below.

Cheng J, Diamond M.
SCUBA diving for individuals with disabilities.
Am J Phys Med Rehabil. 2005 May;84(5):369-75. Review.
http://snipurl.com/o92y

Potential Medical Problems in Divers with Disabilities

Osteoporosis and Fractures
Immobilization and paralysis can place some people with disabilities are at risk for osteoporosis.8,9 Divers at risk for pathologic fractures should seek dive boats with access platforms near water level for easier transfers in and out of the water. It would be rare for dive boats to have lifts that are commonly found in accessible pools. Many neurologic disorders have loss of sensation and fractures may go unrecognized. Unexplained lower limb swelling or redness should be evaluated for possible pathologic fracture.

Medical Implants
Questions are posed concerning the integrity of medical appliances when exposed to the increased barometric pressures associated with SCUBA diving. Many individuals with disabilities such as spina bifida have connections between the brain anf the abdominal cavity (ventriculoperitoneal shunts) for the treatment of hydrocephalus (excessive fluid on the brain). Huang et al.10 subjected four ventriculoperitoneal shunts to one and four atmosphere absolute in a hyperbaric chamber and found that all shunts performed according to manufacturers’ specifications. They reasoned that any increase in pressure will compress all fluid-filled compartments. Therefore, there would be no significant change in gradient between intracranial and intraperitoneal pressures. Preliminary studies have been carried out for cochlear implants in a hyperbaric chamber, illustrating that the implantable components of various cochlear implants can withstand pressures of up to six atmospheres without damage or failure of critical seals.11

Intrathecal baclofen pumps are increasingly being utilized in the management of spasticity and dystonia. Akman et al.12 described a case of retrograde leakage of cerebrospinal fluid (CSF) into the infusion pump reservoir of an intrathecal baclofen pump (Medtronic SynchroMed, Medtronic, Minneapolis, MN) during hyperbaric oxygen therapy. Medtronic does not recommend exposing their intrathecal baclofen pumps to pressures of 2 atmospheres absolute (SynchroMed II Technical Manual, Medtronic).

Thermal Regulation
There is an inability to maintain heat regulation in many disabling conditions. For individuals with this deficit, diving should be undertaken in warm water regions and neoprene wetsuits should be utilized. Deeper diving will cause increased compression of the air in neoprene wetsuits. Because a large component of the insulating quality of wetsuits is provided by the air trapped in the material, compression of these garments will decrease their insulating capabilities.13 When diving to greater depths, the need for increased thermal protection should be anticipated due to the compression of neoprene and the much colder water. Peripheral vasoconstriction, as an adaptation to minimize the strain caused by loss of body heat, may compromise circulation to the limbs and may need to be minimized.13 This vasoconstriction may decrease already decreased circulation to the limbs of some individuals with paraplegia. For example, Boot et al.14 found that individuals with spina bifida and spinal cord injury have peripheral arterial vasculature that was of smaller diameter, lower flow, and higher shear stress when compared with controls. These changes may compromise optimal regulation of the peripheral vasculature. For individuals with spinal cord injury at the neurologic level of T6 and above, exposure to cold water may increase sympathetic nervous system activity, inducing or exacerbating autonomic dysreflexia. 15 Development of autonomic dysreflexia at greater depths may become life-threatening. The need for slow ascent and safety stops may prevent the individual from receiving needed medical care quickly. Individuals with spinal cord injury who are at risk for autonomic dysreflexia should be monitored for common symptoms such as headache, vision changes, and flushing.

Atrophy and Hypotrophy
It should be noted that due to atrophy and hypotrophy of the lower limbs associated with paraplegia and tetraplegia and other disorders, regular wetsuits may not fit properly and custom wetsuits may be necessary to ensure proper fit and optimal heat retention. Because of decreased muscle mass in the lower limbs there may be increased buoyancy and ankle weights may be required to gain neutral buoyancy in the lower limbs. Due to increased buoyancy, this may be worsened when a full wetsuit is worn. 7

Cardiovascular Issues
Paraplegics and some amputees must rely on the upper limbs for propulsion and there are some physiologic factors that need to be considered when the upper limbs alone are used for propulsion. Activities performed with the upper limbs compared with the lower limbs require higher myocardial oxygen consumption at the same total oxygen consumption inducing more stress by upper limb propulsion underwater. Cardiac disorders are common with many neurologic and muscular conditions such as the muscular dystrophies/myopathies, Friedreich’s ataxia, and many syndromes. The shift of blood into the central circulation resulting from water immersion may aggravate congestive heart failure.17 There is also increased myocardial demand in diving due to increased exertion.13 In addition, immersion in cold water can also cause a significant increase in metabolic rate.15 Given these potential stresses on the cardiovascular system during diving, cardiac function should be evaluated carefully in those individuals who have documented cardiac disorders or conditions that predispose them to cardiac pathology. The use of webbed gloves can help facilitate propulsion with the upper limbs and disabled divers may also opt for the use of motorized propulsion devices that are available from several manufacturers and utilized by many nondisabled divers as well.

Venous Stasis
Levey et al. investigated the relationship of spina bifida and deep venous thrombosis and speculated that individuals with spina bifida may be at higher risk due to venous insufficiency and lower limb paresis.18 There is no direct evidence that SCUBA diving increases the risk of deep vein thrombosis. But, given the increase in prevalence of deep vein thrombosis in individuals with spina bifida, it would be prudent to monitor closely for signs and symptoms such as lower limb swelling and dyspnea that may suggest deep vein thrombosis or pulmonary embolus.

Decompression Sickness
The brain and spinal cord contain myelin, which is very susceptible to excess nitrogen supersaturation after ascent.17 Symptoms of air embolism affecting the brain or spinal cord include unconsciousness with stroke-like symptoms, paralysis, seizures, bowel/bladder dysfunction, sensory abnormalities, fatigue, personality change, poor concentration, irritability, and changes in vision.17 The cortical gray matter is more efficient at releasing nitrogen compared with the spinal cord.1,19 Therefore, the spinal cord is at particular risk for decompression sickness. Venous bubbles can cause thrombosis of the venous plexus surrounding the spinal cord, resulting in venous stasis and spinal cord ischemia.1 However, there is no direct evidence that individuals with spinal cord dysfunction or cortical neurologic disorders are at greater risk of decompression sickness of the brain or spinal cord. Boot et al.14 found that individuals with spina bifida had common femoral arteries that were smaller, with decreased blood flow, compared with normal controls. It is unknown if these arterial characteristics increase the risk of decompression sickness and there are currently no studies investigating the appropriateness of the use of current dive tables by the disabled population. Individuals with disabilities may be at increased risk in the context of decompression sickness because neurologic impairment caused by the decompression sickness can be confused with or masked by the neurologic signs and symptoms associated with the divers’ disease processes. Therefore, it is very important for the disabled diver and his or her dive companions to be familiar the signs and symptoms of decompression sickness and be able to contrast them with the disabled individual’s baseline state.

Seizure
Many individuals with disabilities have seizure disorders related to their disease processes. Any seizure underwater would result in severe drowning risk and would also be a danger to that diver’s partner. Therefore, seizure disorder requiring ongoing medical management is a strict contraindication to SCUBA diving.17,20 Some certifying agencies, however, will allow divers who have been seizure-free without medications for 5 yrs to participate in their diving programs.

Pneumothorax
Pneumothorax can be spontaneous or result from trauma. Spontaneous pneumothorax can be associated with structural abnormalities and lung disease.21 It is a strict contraindication for SCUBA diving because the underlying cause may still be present at the time of diving.20 Many individuals who have disabilities resulting from traumatic events have had pneumothoraces. Traumatic pneumothorax, however, is not a contraindication provided that the injury is well healed.

Latex
Latex allergy is rare in the general population, with a prevalence of 1%.22 However, it is a concern for individuals with spina bifida and other disorders.22–25 Latex allergy is very common in these populations, with up to 60% of individuals with spina bifida having allergies to latex.25 It is an immunoglobulin E–mediated hypersensitivity reaction to natural rubber latex that can result in urticaria, rhinitis, bronchospasm, and anaphylaxis.23 Bernardini et al.25 found that 25% of subjects with spina bifida had latex sensitization, and only 33% of those individuals have had clinical reactions to latex. Although severe reactions are rare, such reactions at greater depths would present a life-threatening event. Therefore, previous screening is important. Individuals at risk for latex allergies, especially people with spina bifida, may wish to consult an allergist for skin prick or serum latex-specific immunoglobulin E antibody testing before considering SCUBA diving. Those individuals who are at risk may wish to have antihistamines and intramuscular epinephrine available in case of a serious reaction. It may also be prudent to contact the manufacturers of the equipment to be used to determine the precise material content to further decrease the risk. The majority of modern diving masks and snorkels are made from silicone. Also, there is usually no natural latex in neoprene wetsuits. However, certain seals and tubing may contain latex, as may seams in certain wetsuits. Latex seals are much more common in dry suits in which water-tight seals are required. Wetsuits manufactured from neoprene rarely have latex seals. Air tubing may contain natural latex, but the latex is usually vulcanized with other materials and therefore would not likely cause a hypersensitivity reaction. However, it may be best to contact individual manufacturers to confirm the latex content in their air hoses. Alternatively, silicone tubing can be utilized to further reduce the risk.

Skin
Many conditions resulting in paraplegia are also associated with sensory deficits. Because of insensate skin, these individuals are at risk for developing pressure ulcers and injuries from trauma. Muscle atrophy also results in decreased protection normally afforded by muscle mass and therefore increases the risk of pressure ulcers. In addition, these individuals are at risk for unrecognized burns from sun exposure. Wetsuits may provide a certain level of protection from skin injury. During the dive, they may protect from abrasions and lacerations while preventing sunburn while on the surface.

Bladder Management
Water immersion and cold exposure have been found to cause diuresis by increasing plasma volume and increasing the release of factors such as atrial natriuretic peptide.26,27 Changes in urine production can become a factor in individuals requiring catheterization because of a neurogenic bladder. Individuals whose bladder programs include clean intermittent catheterization may be required to catheterize more often to address the increased diuresis. This may be difficult given the limited space of a dive boat. It would be an important consideration to identify dive boats that have private spaces available for bladder management and a means of washing hands to maintain the aseptic nature of the procedure. Individuals who are on clean intermittent catheterization programs may regularly limit their intake of fluids to reduce the frequency of catheterizations throughout the day. While SCUBA diving, the sources of fluid loss as previously described and those associated with increased exertion and ambient temperature may predispose the diver to dehydration. In addition, wetsuits provide significant thermal protection while in the water. However, prolonged wetsuit wearing may result in hyperthermia, increased sweat production, and dehydration. 13 Therefore, careful monitoring of fluid intake and output balance and monitoring for symptoms of dehydration are very important in this population. Also, bladder distention can be of particular concern for spinal cord–injured patients with a neurologic level above T6 who are at risk for autonomic dysreflexia.

Ear Barotrauma
Problems associated with middle-ear spaces and paranasal sinuses are the largest source of morbidity among SCUBA divers.20 As a diver descends, external pressure increases and pushes on the tympanic membrane. This pressure needs to be equalized in the middle ear through the oropharynx via the eustachian tube.17 Equalization involves forcefully exhaling against closed (pinched off) nares. Inability to properly equalize will cause barotrauma and may result in pain, acute hemorrhagic otitis media, or tympanic membrane rupture. 17,20,28 Therefore, before diving, each individual should be evaluated for the ability to perform this maneuver independently or with the assistance of another diver.

Asthma
Asthma affects 6–7% of the general population in the United States, often with childhood onset.17 Some have supported that any history of asthma is a strict contraindication.20 However, asthma varies greatly in severity and in its triggers across individuals. 3 Bove17 states that individuals with mild asthma should not be prohibited from diving. Neuman et al.3 suggests that individuals with normal airway function at rest with little airway reactivity to exercise or cold air inhalation may have risks of pulmonary barotrauma similar to nonasthmatic individuals. However, air-trapping at depth while breathing compressed air in individuals with asthma can lead to serious pulmonary barotrauma. 3,29 Therefore, subjects with a history of asthma should be screened carefully. Additional research may be helpful to better describe the risks for different asthma severities and triggers as opposed to using a history of asthma as a strict contraindication for diving.

Certification
Certifying bodies for recreational SCUBA diving such as the Professional Association of Diving Instructors and the National Association of Underwater Instructors have requirements for swimming and fitness. For example, Professional Association of Diving Instructors requires that an individual be able to tread water for 10 mins and swim for 200 meters independently, even though these skills are rarely needed in SCUBA diving. The authors advocate that for full certification, individuals with disabilities should be held to the same requirements and standards as their able-bodied peers. This is to ensure the highest level of safety for the disabled diver. In addition, an important component of SCUBA certification is the ability to perform skills necessary to assist a dive partner. Any disabled individual who is to be a candidate for full certification should be able to carry out these responsibilities. The Handicapped SCUBA Association has established a hierarchical certification structure based on each diver’s abilities. This system allows individuals with disabilities to participate in SCUBA diving at different levels of independence based on their level of function (Table 1).7

CONCLUSIONS
SCUBA diving is an adventurous sport that allows participants to explore a diverse, exciting marine environment. Guidelines have been established by SCUBA certification organizations to minimize injury and injuries often occur when these guidelines are violated. However, some individuals may experience injury even when diving conservatively. Mortality rates in recreational SCUBA diving are estimated to be one to nine in 100,000 divers.1,2,30 The authors advocate that SCUBA diving be made available to as many interested individuals as possible. It can be a great source of self discovery and a means of building confidence and independence. However, individuals with disabilities present with many medical conditions that need to be considered carefully by their physicians before certifying them as fit to dive. Recognizing and addressing risk factors can help to limit morbidity and mortality. Additional research into how the unique anatomy and physiology of individuals with disabilities interact with a hyperbaric, marine environment would help to better refine guidelines and allow safer diving in the least restrictive framework.


TABLE Levels of certification available from the Handicapped SCUBA Association
Level A
Able to provide equal assistance to a fellow diver in case of an emergency. Qualified to dive with another certified diver, including a level A diver.

Level B
Able to care for self in case of an emergency but cannot provide a fellow diver equal assistance in case of an emergency. Qualified to dive with two certified divers who may be level A.

Level C
Able to safely use SCUBA underwater but unable to effectively care for self or a fellow diver in case of an emergency. Must dive with two certified divers, one of whom has been trained by a nationally recognized diver training agency in diver rescue. In most cases, this would be an instructor, assistant instructor, or dive master.



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Hope this is helpful!

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