This article, extracted from a chapter in the second edition of Diving Science by Michael B. Strauss, MD, is an excerpt from Part III of the text revision, which covers special diving types, situations and environments. This current article includes introductory information and definitions in addition to cardiovascular and endocrine-metabolic disabilities.
Other articles in the three-part series to be published in subsequent issues of WCHM will deal with other organ system disabilities, disabilities from previous medical problems of diving, plus a section on organizations and agencies which provide support for divers with disabilities.
Introduction and Defining Disabilities
The Scope of Handicaps The marvels of scuba diving have the potential for greatly enhancing the psychological as well as the physical well being of those with handicaps. Disabilities and handicaps are related terms (Figure 1).
FIGURE 1. Disability Versus Handicap
They can refer to a physical condition that makes ordinary activities more difficult, something that causes unusual difficulties with particular activities, or something that gives others an advantage due to the condition. All have implications for the handicapped scuba diver. Many, if not all of the conditions discussed in this chapter are mentioned in other chapters of this text. For example, in the young and the older diver chapters, the subject of disabilities and diving with medical conditions was mentioned. This chapter is a more comprehensive examination of disabilities as they pertain to scuba divers and is organized by body organ systems considered in alphabetical order. This organization minimizes the assumption that one may assume that the first problems mentioned are the most important.
Uniqueness The aquatic environment is so different from the terrestrial environment that it offers those with handicaps a “new world” of experiences (Table 1). The density of water being over 700 times greater than that of air provides buoyancy and helps counter effects of gravity for those with missing extremities, weakness or traumatic brain injuries. Immersion in the aquatic medium is so different from the air environment that those with post-traumatic stress disorders may well forget their anxieties and depression while submerged. Warm water can add tactile “comfort” unlike any experienced in air. Visualization of the underwater flora and fauna is unique enough that it has the potential for making the handicapped diver feel “special” and something that non-divers are unable to experience.
TABLE 1. Terrestrial versus Aquatic Environments
(Benefit of the aquatic environment)
||Communications by other than verbal means required
||Compensates for the ability to communicate, such as those with speech impediments, deafness/muteness and autism
|Movement of Extremities
||Moderates and smoothed-out by the density effect( over 700 times greater than air) of water
||Possibly compensates for spasticity, tremors, tics, and athetoid movements
||As they exist
||Blunted or contraindicated, (i.e. observe but don't touch)
||Gives clues to the dive buddy how well the handicapped diver follows instructions
||Controlled with clothing and the excellent insulation effects of air
||Challenging due to the thermal conductivity (20 times greater than air) and the specific heat (1000 times greater than air) of water
||The dive organizer/dive buddy must ensure thermal comfort is achieved so as not to lessen the positive dive experience
||Limited by the density and clarity of water; objects magnified; color expression lost with descents
||A new experience for the handicapped diver who had not dove previously
||Direct effect of gravity
||Nil due to the buoyancy effect of water
||Helps to compensate for muscle weakness, limb losses, balance and coordination problems
Accommodations Since the handicapped diver has disabilities, special accommodations need to be made. These include choosing the ideal diving site commensurate with the diver’s handicaps. Ideally, warm water with good visibility and optimal diver support services such as trained dive boat personnel and user-friendly entry and exit ramps should be selected for the diving sites. As in all scuba diving activities, but even more important for the handicapped diver, dive planning is essential. The goals are to maximize the experience while minimizing the hazards. Finally, and most importantly, the handicapped diver requires a dive buddy who is aware of and understands the disabled diver’s handicaps, is fit and experienced enough to handle emergency situations for the handicapped diver, and who is willing to give full attention to the handicapped diver to maximize the diver’s experiences while sublimating his/her own. The buddy must have full control of the situation and know when to “call it quits” or not allow the handicap diver to continue with or even do the dive.
Of all the considerations for the handicapped diver, the dive buddy is undoubtedly the most important. Without a knowledgeable and competent dive buddy, the handicap diver should not engage in scuba diving activities. The buddy needs to be dedicated to make the handicapped diver’s experiences as safe and enjoyable as possible. The buddy is also responsible for the decision about when to not dive or to prematurely terminate the dive.
A Tool for Assessing Wellness In managing our wound care patients we use a quick survey to assess their wellness; it was previously described in the older age diver chapter (Table 2).¹ This tool can be easily applied to the handicapped individual who wants to scuba dive. Five assessments related to health and vitality are graded on a 2-point (ideal situation) to 0-point (worst possible situation) scale. The five assessments are: 1) Ability to do activities of daily living, 2) Mobility, 3) Comorbidities, 4) Smoking/ immunosuppressor history and 5) Neurological deficits. When they generate a 0 to 10-point Score. Low (0 to 3 point) scores justify absolute contraindications for scuba diving. Intermediate scores (3½ to 7 points) are relative contraindications to diving and require medical evaluation and clearance for diving. High score (7½ to 10 points) quantify the diver as “healthy” and generally quantify them as able to scuba dive without restrictions. The remainder of this chapter describes how disabilities as occurring in body systems impose handicaps on divers.
TABLE 2. The Wellness Score and Its Usefulness for Making Recommendations about Diving Disabilities
Conditions Cardiovascular disabilities are associated with the heart muscle blood supply, heart muscle function, heart rhythms and circulation to other parts of the body (Figure 2, Table 3). If one or more of these conditions are present, scuba diving becomes a relative or an absolute contraindication for diving depending on the severity. If any are present, the potential diver requires a cardiac clearance before scuba diving. Invariably, this group of potential scuba divers would have Wellness Scores in the impaired range (3 ½ to 7 points) range. Those with decompensating conditions (Wellness Scores in the 0- to 3-point range) would probably not seek to scuba dive because of the severity of their medical problems.
FIGURE 2. Heart considerations that can have ramifications for divers
Evaluations and Clearances Tests such as electrocardiograms (ECGs), echo cardiograms, stress EKGs and/or coronary angiography may be required to ascertain the severity of the heart disease and make the best possible decision whether or not to “clear” the individual for scuba diving. As part of the cardiac clearance, recommendations should be made for an exercise/fitness program. If OK’d for diving, then the potential diver should be referred to a diving medicine physician for a secondary clearance and advice for diving with the disability. The advice is mostly common sense but should include recommendations for maximum depths of diving, how to choose “ideal” diving sites and conditions, the selection of conservative dive settings on the computer, reinforcement of ascent rates and necessity of the rest stop, and importance of maintaining fitness/ cardiac conditioning.
Patent Foramen Ovale The foramen ovale is an opening in the septum between the right and left atria of the heart that is necessary for circulation through the heart of the fetus. It typically closes at birth, but in about 25 percent of the population it remains partially or fully patent.5 Ordinarily this anomaly goes unnoticed. However, venous gas bubbles that are thought to be a universal finding with ascents from compressed gas diving may bypass the lungs (which filter out the bubbles) and pass into the left side of the heart (Figure 2). The bubbles, in turn, can be carried to the brain and heart as well as other organs and occlude circulation to these structures.
If an apparently “undeserved” case of decompression sickness occurs and involves the brain or heart, a patent foramen ovale (PFO) should be suspected.6 A bubble study with Doppler can document the presence of a PFO. Options after identification include cessation of scuba diving or using the percutaneous technique to patch the PFO. If successful, as is usually the case, the PFO patient may resume scuba diving.
Anticoagulants, Pacemakers and Scuba Diving Anticoagulants are prescribed for patients with atrial fibrillation (irregular heart rates) and after coronary stenting/ angioplasty. Scuba diving per se is not an absolute contraindication for patients using anticoagulants. The major concern is uncontrollable bleeding from injuries from shark bites or other marine animals and lacerations from obstacles in the water or boat propellers. Since these occurrences are extremely rare, the really important considerations are the patient’s cardiac function and fitness. This places the diver who is on anticoagulants in the same relative contraindication for scuba diving category as described above for heart disease. Recommendations for medical clearances to dive and selection of “ideal” diving sites are consequently the same.
Similar advice is appropriate for scuba diving with pacemakers. Diving with pacemakers is another relative contraindication. In addition to the reason for the pacemaker and the patient’s cardiac function, the pressure/ depth limit of the pacemaker needs to be as certained. Usually pacemaker pressure/depth limit information is available from the manufacturer of the pacemaker. One study showed pacemakers continued to function to 100 FSW/30 MSW depths.7 Those peacemakers that are implantable cardioverter defibrillators (ICDs) are in our opinion an absolute contraindication for scuba diving. Typically, they have a low voltage electrical discharge for mitigating slowed heart rhythms and a high voltage shock for life threatening rhythms such as ventricular fibrillation (VF).
TABLE 3. Cardiovascular Disabilities and Diving
||Scuba Diving Ramifications
|Blood Supply (Coronary Artery Disease)
||Interferes with heart muscle oxygenation, carbon dioxide removal and nutrition
||Heart attack with death of cardiac muscle limits cardiac output
|Heart Muscle Function (Cardiomyopathies such as hypertrophic, restrictive, dilated from alcohol, cocaine, amyloidosis, hemochromatosis, coronary artery disease, heavy metals, etc.)
||Loss of heart contractile power and/or ability
||Impaired cardiac output makes patient unable to meet demands of exercise
Heart Rhythm Irregularities (Atrial fibrillation, atrial flutter, bradycardia, tachycardia, ventricular fibrillation)
|Interferes with heart filing and blood outflow
||Water immersion, especially if cold precipitates arrhythmias, specifically bradycardia (Ref.2)
|Circulation to Body Parts (Peripheral artery disease)
||Inadequate perfusion to supply oxygen and metabolites to muscles and other body organs
||Pain, weakness, and/or cramping with muscle ability. Limited ability to increase muscle activity for responses to emergencies
If the patient is at risk for VF and associated loss of consciousness in the water, even if only temporary, the consequences can be disastrous with water aspiration, near-drowning and drowning. Other absolute contraindications for scuba diving with pacemakers exist for commercial, scientific and military activities.
Peripheral Artery Disease It is unusual for this problem to be a consideration for scuba diving. If severe enough, the patient most likely is already limiting his/her activities and scuba diving is not a consideration. If mild, but claudication (i.e. ischemic leg or thigh cramping-like pain) is observed with walking, the patient may be able to swim without symptoms. However, the use of fins, especially if needed for fast swimming and/ or emergencies, may precipitate claudication and compound the problem, that is the cramping will cause cessation of swimming activities and compromise extrication from the emergency. Hence, scuba diving is not recommended for such patients. Interventions such as bypass surgery, angioplasties and/or stenting are effective in managing peripheral artery disease and if successful, elevate an absolute to a relative contraindication for diving.
FIGURE 3. Normal heart anatomy and heart with patent foramen ovale
Endocrine and Metabolic Considerations
Diabetes Mellitus and Obesity The two main endocrine metabolic disorders with respect to scuba diving are diabetes mellitus (DM) and obesity. However, other endocrine gland functions also have some relevance to scuba diving (Table 4). The main concerns with DM is that the diver may become hypoglycemic during the scuba dive, become confused and even lose consciousness while underwater. Both are situations that may require emergency ascents and lead to arterial gas embolism or decompression sickness or if consciousness is lost, drowning. However, there are guidelines in the literature that embrace scuba diving in the diabetic even if the patient is insulin dependent.8,9
Considerations for scuba diving with diabetes include that the patient has a history of stable blood sugars and is compliant with his/her diabetes management as reflected in glycosylated hemoglobins (HgA1c) in the six percent or less range. Blood glucoses should be measured immediately before starting the scuba dive and at the dive’s termination. This reflects a proactive approach to avoiding hypoglycemia during the course of and immediately after the dive. Emergency glucose sources in a diver’s buoyancy compensator pouch should be available in case precursor symptoms of hypoglycemia such as lightheadedness, sweating, or weakness are noted during the dive. Of course the dive should be planned to minimize stresses with the measures mentioned previously.
Obesity Obesity imposes relative contraindications for scuba diving. It is a generic term that represents a spectrum of findings from being mildly overweight to morbid obesity. The body mass index (BMI) is used to gauge obesity. Over weightiness is defined as a BMI greater than 25, obesity greater than 30, and morbid obesity as a BMI greater than 40. Another measure of morbid obesity is a body weight of 100 pounds (45 kilograms) over ideal body weight, that is a body weight in the 20 to 25 BMI range.
Two major considerations are associated with obesity and scuba diving. The first is an increased propensity for developing decompression sickness.10 This is attributed to fat tissues having five times the affinity for nitrogen than the surrounding tissue fluids of the body. Fat is considered an intermediate tissue with respect to ongassing and offgassing due to a highly regulated (by sympathetic nervous system) blood supply. With longer, deeper dives increased ongassing occurs in this tissue. If ascent and offgassing is based on tissues that offload nitrogen faster than the nitrogen saturated fat tissues, sufficient gradients may develop to generate bubbles and lead to decompression sickness symptoms.
FIGURE 4. Endocrine Glands and Their Implications for Diving
The other major consideration for the obese diver is fitting of equipment. The obese diver will require substantially more weights for buoyancy control. This coupled with the buoyancy of ¾-inch (7 mil) thick neoprene wetsuit can result in requiring 40 to 50 pounds (18 to 23 kilograms) of weights to achieve neutral buoyancy. This added weight makes water entries and exits as well as rescue efforts if an emergency develops challenging. The extra exertion required could subject the obese diver to cardiac events. Other medical problems are frequent in the obese diver including the metabolic syndrome (hypertension, hyperlipidemia [increased triglycerides—i.e. bad cholesterol], increased blood glucose, increased abdominal girth, and low levels of high density lipoproteins [i.e. good cholesterol]; arthritis from overloading joints from the added body weight; obstructive sleep apnea; gastrointestinal reflux disease; depression; infertility; and incontinence). If the obese diver is determined to scuba dive, he/she should be motivated enough to lose weight and optimize the medical management of existing comorbidities. Over weightiness is a reason for disqualification of military divers.
Alcohol The social use of alcohol is not a contraindication for scuba diving. However, it should not be consumed before a scuba dive. It can blunt judgment and may compound the effects of nitrogen narcosis and can occur in situations where it ordinarily would not. Those with alcohol dependence (i.e. alcoholics) should not scuba dive until they have been detoxed and can be labeled as recovered. Another consideration about immediate alcohol use before a scuba dive is that it is a diuretic (stimulates the production of urine). This can contribute to dehydration and, in turn, interfere with the circulation system’s ability to offload nitrogen during the ascent phase of the dive. These events may be precursors to decompression sickness.
TABLE 4. Endocrine Disorders and Diving
||Possible Ramifications for Diving
||"Master" control gland; sends hormonal signals to other glands to increase or decrease their activity; regulates growth
||Management can be challenging and requires medications for loss of function of all the pituitary target glands
||Absent function is an absolute contraindication for diving – if insufficient function it becomes a relative contraindication
||If hypofunctioning it can lead to poor cold-water tolerance, weight gain, and delayed responsiveness (e.g. excessive tiredness). If hyperexcitability, tachycardia, weight loss, and heat intolerance
||Thyroid problems when well controlled with medications do not present a contraindications for diving
|Islets Cells of Pancreas
||Generate insulin and control its release (with signals from blood glucose and pituitary gland)
||See previous discussion on diabetes in this section
||Diabetes imposes relative contraindications for diving
||Releases "flight or fight" hormones (adrenalin and noraadrenalin) as well as cortisol, which affects blood pressure, glucose, growth, and sexual characteristics
||If non-functional, ability for a diver to response to a crisis may be impaired
||If function is impaired, medial clearance for diving needed from an endocrinologist as well as a diving medicine physician. If cleared, diving should be done in "ideal" conditions
|Ovaries and Testes
||Both produce testosterone (a third more in males) plus regulate reproductive tissue
||Over production may contribute to "macho" action of the diver, underactivity may lead to lethargy, depression, and muscle weakness
||Malfunction or absence probably present no contraindications for scuba diving
Other Metabolic Considerations Almost all endocrine disorders have ramifications for scuba diving (Table 4). However, if mild or easily controlled with medications, they do not impose contraindications to scuba diving. If severe, they provide absolute contraindications for diving. Thyroid disease is the most controllable of all endocrine disorders. When properly managed, it imposes no restrictions for scuba diving. Steroids and other immune suppressors have ramifications for divers. Their use is a relative contraction for scuba diving. They blunt the body’s inflammatory responses and weaken the immune system. A short course of steroids (e.g. Medrol DosPak®) to control an acute inflammatory condition imposes only a temporary contraindication to diving. Chronic use of steroids for asthma, colitis, or collagen vascular diseases is a contraindication for scuba diving. The steroids blunt the adrenal response to stress; however, probably more importantly the reason chronic steroid use is required is the stronger reason for not scuba diving. Although pregnancy is a temporary contraindication for scuba diving, lactation in the female diver is not. Viagra® and related medications do not seem to interfere with diving. Some information, anecdotal at this time, suggest it may lessen the chances of decompression sickness occurring.
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