Scuba diving: What you and your patients need to know

ANN MARIE McMULLIN, MD

Department of Emergency Medicine, Cleveland Clinic

Scuba diving: What you and your patients need to know

■ A B S T R AC T

Self-contained underwater breathing apparatus (SCUBA) diving continues to gain popularity. General practitioners need to know the health requirements and contraindications so they can counsel patients appropriately. SCUBA diving injuries may not be apparent immediately and require knowledge and understanding for accurate diagnosis and treatment.

7 MILLION PEOPLE are estimat-             to participate in self-contained underwater breathing apparatus (scuba) div- ing,1 so you are highly likely to encounter one in your practice.     Scuba diving requires rigorous health screening to prevent injury or accidents. Most reputable diving instructors and schools require a medical statement from prospective divers. Health care professionals must be aware of the requirements, contraindications, and possible injuries of diving so that they are able to advise their patients properly and diag- nose diving-related injuries.     This article describes general recommen- dations for screening scuba divers and suggests specific workups and contraindications to div- ing. It also provides an overview of potential diving injuries and their treatment.

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■ KEY POINTS

General considerations for diving clearance, requirements for further workup, and contraindications to diving must be reviewed for each patient.

In the event that a patient presents with health concerns after a diving trip, barotrauma, decompression sickness, and air embolus should be considered as possible diagnoses.

Divers Alert Network (DAN) is a good medical resource for physicians and patients should they have more specific questions. DAN can be contacted at 1-919-684- 2948, www.diversalertnetwork.org, or www.WRSTC.com.

■ PREDIVE MEDICAL CLEARANCE

General considerations for screening patients are shown in TABLE 1.2     Each patient should have a predive clear- ance workup based on his or her medical his- tory and current complaints. The patient’s medical and surgical histories should be reviewed and further evaluation considered on the basis of the medical history (TABLE 2).2–5 A review of systems will ensure that no cur- rent health condition will hinder diving, and a physical examination should be performed to complement the history.     Absolute contraindications to scuba div- ing include, but are not limited to, hyper-

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TA B L E 1

General considerations for assessing capacity to dive

Exercise tolerance   Equipment is bulky and heavy (> 35 lb) and sometimes must be carried over uneven terrain and for excessive distances    or up and down the ladder of a boat   Swimming is easier in fins and a buoyancy vest, but is still difficult in certain currents

Breathing   When ascending from depth, any process that prevents airflow from the lungs (eg, emphysema, bulla, other causes of air    trapping) puts the diver at risk for pulmonary overinflation, which can lead to alveolar rupture and air embolus

Mental status  Life-threatening events can occur underwater that require certain actions  A diver must not be at increased risk of change or loss of consciousness such as would occur with a seizure or    hypoglycemic episode  Panic is a normal response to even non-life-threatening events at depth, but a diver with an abnormal panic or anxiety    response may put himself or others at risk if he or she reacts inappropriately

Recent health   A vomiting or coughing diver can drown   A diver with an upper respiratory infection who cannot equalize the pressure in the ears or sinuses can rupture    a tympanic membrane or sinus   Recent surgical wounds can easily get infected   Uncontrolled hypertension puts a diver at increased risk of pulmonary edema

Medications  Review medications that can alter mental status or impair exercise tolerance  The real bottom line is: if a patient requires a medication to dive (eg, a decongestant, antiemetic, antiseizure medication,   or antidysrhythmic), he or she should be advised not to dive

trophic cardiomyopathy, right-to-left intracar- diac shunt, seizures, history of cerebrovascular accident, spontaneous pneumothorax, gastric outlet obstruction, recurrent bowel obstruc- tion, claustrophobia, untreated panic disorder, and numerous ear, nose, and throat disorders. The major concern in these cases is sudden loss of consciousness, increased risk of decom- pression sickness and barotrauma, or risk to other divers due to inappropriate response to stress while diving.      There are many other situations in which a patient should be cautioned or sent for fur- ther evaluation prior to clearance. For instance, a history of coronary artery disease may necessitate a stress test to prove exercise tolerance. Patients with a pacemaker must ensure the device is certified to withstand changes in pressure. Patients who have had previous decompression sickness or dive-relat- ed injury should have a specialist evaluation prior to clearance to determine risk of recur- rence. Pregnant women should be advised of

the unclear risk of fetal emboli. Abnormal facial anatomy may affect mask or mouthpiece fit. None of these examples is an absolute con- traindication, but all must be addressed fully prior to clearing a patient to dive. A more complete list of considerations can be found in TABLE 2.

■ POTENTIAL DIVING INJURIES

In the unlikely circumstance that you are the first person to evaluate a patient for a com- plaint after a recent diving trip, you should be familiar with the potential diving injuries and their treatment.

Barotrauma Barotrauma can involve any gas-filled body space and involves tissue damage due to a fail- ure of that space to equalize its pressure with the ambient water pressure.6 All forms of barotrauma can occur even at very shallow depths if the proper procedure for ascent is not

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The most common diving injury is middle ear barotrauma (‘ear squeeze’)

followed or if preexisting conditions allow for air trapping.      Middle ear barotrauma. The most prevalent injury associated with diving is middle ear baro- trauma or “ear squeeze.” Middle ear barotrauma most often occurs on descent when a diver fails to equalize the pressure between the air in the middle ear and the ambient water. Pressure and volume follow Boyle’s law: PV = K (where K is a constant; at a constant temperature, the volume [V] of a gas varies inversely with the pressure [P] to which that gas is subjected).7      For example, as a diver descends, the increase in ambient water pressure compresses the gas in air-filled body spaces such as the middle ear. The diver must address this vol- ume loss by adding more gas to this space (equalizing it) to prevent injury.      Divers equalize the pressure on descent with a gentle Valsalva maneuver, but this maneuver may be impaired if the eustachian tube is blocked. The external pressure may be so great as to implode (rupture) the tympanic membrane, or it may just cause pain and tym- panic membrane hemorrhage. Other associat- ed symptoms may include vertigo, tinnitus, and hearing loss.      Treatment of middle ear barotrauma includes decongestants, and if the tympanic membrane is ruptured, the addition of antibi- otics (only if there is purulent drainage, in which case one should start with typical treat- ment for otitis media), analgesia, and referral to an otolaryngologist. No diving should be permitted until symptoms are improved and the tympanic membrane is healed.      Inner ear barotrauma. Similar symptoms (vertigo, tinnitus, hearing loss) may occur with inner ear barotrauma, which is generally caused by a too-forceful Valsalva maneuver, resulting in rupture of the round or oval win- dow due to unequalized pressure between the middle and inner ear. If inner ear barotrauma is suspected, no findings will be noted on eval- uation of the tympanic membrane (which dis- tinguishes it from middle ear barotrauma). It must, however, be distinguished from inner ear decompression injury, as the treatments for each are markedly different. The two con- ditions can usually be distinguished by the his- tory. Barotrauma more often occurs on descent and continues thereafter, whereas

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decompression injury is noted gradually on ascent or after exit from the water.7      Treatment of inner ear barotrauma involves referral to an otolaryngologist, bed rest, elevating the head of the bed to 30 degrees, and stool softeners to avoid increas- ing intracranial pressure.      Sinus, tooth, and facial barotrauma. Barotrauma can also affect the sinuses, caus- ing headache, epistaxis, and sinus pain, or the teeth, causing localized dental pain, usually at the site of a filling.      Tooth squeeze will require treatment by a dentist with replacement or repair of the fill- ing, and sinus barotrauma is treated with decongestants.8 If a sinus has ruptured, further workup is needed to assess for pneumo- cephalus, and the patient should be referred to an otolaryngologist.7      Gastric barotrauma. By the same mecha- nism, barotrauma on ascent can occur in the gastrointestinal tract, where gas is trapped, and may lead to rupture of a hollow viscus.      Gastric barotrauma or hollow viscus rup- ture is rare but requires emergency treatment.      Pulmonary barotrauma. If the diver holds his or her breath on ascent and does not exhale properly or has significant underlying pulmonary disease, the lungs can overinflate. Overinflation of the lungs can lead to baro- trauma of the alveoli, causing them to rupture, with emphysema extending into the neck or mediastinum, and possibly to air embolus. Pneumothorax is rare, but it must be consid- ered if the symptoms are suggestive.9      Pulmonary barotrauma rarely requires specific treatment other than observation, but as indicated in TABLE 2, evaluation by a pulmo- nologist is needed before the patient dives again.      Eye injury. Diving mask pressure must be equalized by gentle exhalation through the nose on descent; mild superficial trauma can occur to the skin and eyes in the form of petechiae and subconjunctival hemorrhages if this is not done.

Decompression sickness One form of decompression illness, termed decompression sickness or “the bends,” results from the inflammatory response to bubbles of inert gas forming in the blood and body tissues when the pressure is significantly and rapidly

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TA B L E 2

Suggested predive evaluation based on medical history

Cardiovascular conditions   Coronary artery bypass grafting   Percutaneous coronary angioplasty   Coronary artery disease     Concerns: Exercise tolerance is vital to diving—a      stress test in which 13 metabolic equivalents (METs) is      accomplished with no electrocardiographic changes or      symptoms is required for clearance to dive if ability is in      question and may be helpful for coronary artery disease      risk assessment in patients > 40 years old   Congestive heart failure     Concerns: Significantly decreased left ventricular function      may affect the body’s ability to handle the excess volume      load, as the body shunts blood centrally in cold water,      putting patients at increased risk of pulmonary edema.   Hypertension   Dysrhythmia requiring medication   Significant valve regurgitation   Pacemakers     Concerns: Consider the condition that necessitated      placement     Pacemaker must be certified to withstand pressure      changes involved in recreational diving

Cardiovascular contraindications   Intracardiac right-to-left shunt     Concerns: Increased risk of venous emboli entering the      cerebral and spinal cord circulation   Hypertrophic cardiomyopathy and valvular stenosis     Concerns: Increased risk of unconsciousness during exertion   History of ventricular tachycardia or > 1 episode of     sustained ventricular tachycardia

Neurologic conditions   Complicated migraines   Head injury   Herniated nucleus pulposus   Multiple sclerosis   Trigeminal neuralgia   History of cerebral gas embolism     Concerns: Ability to exercise in patients with certain      neurologic disorders should be considered     Patients with symptoms that come and go may be      incorrectly diagnosed with decompression sickness if      symptoms present after diving     Risk of seizure should be considered     Those with previous cerebral embolism must be fully      evaluated to determine that risk of recurrence is low

Neurologic contraindications   History of seizure other than childhood or febrile    Concerns: Significant probability of unconsciousness      puts a diver at risk of drowning   History of transient ischemic attack or cerebrovascular    accident    Concerns: Spinal cord or brain areas with abnormal      perfusion may increase risk of decompression sickness   History of previous serious decompression sickness with    residual deficit

Pulmonary conditions   Asthma or reactive airway disease   Exercise-induced bronchospasm   Solid, cystic, or cavitating lung lesion   Pneumothorax secondary to thoracic surgery, trauma, or     previous dive injury   Obesity   History of immersion pulmonary edema   Other previous lung-related dive injury   Interstitial lung disease     Concerns: Any active disease, abnormal pulmonary       function tests, or positive exercise challenge is very       worrisome for diving     Increased risk of breathing challenge with scuba       device as well as possible increased risk of pulmonary       overexpansion     Forced expiratory volume in 1 second and peak       expiratory flow rate should be within normal limits for       diver’s age, sex, race, and height     Exercise test should be negative     Pulmonology consult should likely be arranged before       clearance for diving in any of these cases

Pulmonary contraindications   History of spontaneous pneumothorax

Gastrointestinal conditions   Peptic ulcer disease associated with pyloric obstruction   Severe gastroesophageal reflux disease   Unrepaired hernia of the abdominal wall big enough to     become incarcerated     Concerns: The concern is for air trapping and       expanding on ascending   Inflammatory bowel disease (if debilitating)     Concerns: May impair abilities, or if diving in distant       locale, treatment may not be available

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Gastrointestinal contraindications   Gastric outlet obstruction of a degree sufficient to    produce recurrent vomiting    Concerns: May cause vomiting, which can lead to drowning   Chronic or recurrent small-bowel obstruction   Achalasia   Periesophageal hernia    Concerns: Air trapping and expansion could lead to rupture

Orthopedic conditions   Amputation   Scoliosis   Back pain    Concerns: Impairment of mobility or respiratory      function must be considered   Aseptic necrosis    Concerns: Aseptic necrosis may progress if      decompression sickness affects the joint

Hematologic and rheumatologic conditions   Sickle cell disease     Concerns: Increased risk of decompression sickness      may exist (theoretically), and sickle cell crisis may be      incorrectly diagnosed as decompression sickness   Polycythemia vera   Leukemia   Hemophilia, impaired coagulation     Concerns: Bleeding disorders could worsen the effects      of barotrauma and exacerbate injury associated with      decompression sickness   Raynaud syndrome     Concerns: Digit function may become impaired,      hindering diving abilities   Systemic lupus erythematosus     Concerns: Pulmonary function and exercise tolerance      should be evaluated prior to diving

Metabolic and endocrine conditions  Hormonal excess or deficiency  Obesity  Renal insufficiency    Concerns: Exercise tolerance must be proven

Metabolic and endocrine contraindications  Insulin-dependent diabetes mellitus    Concerns: Risk of potential rapid change in     consciousness resulting in drowning  Pregnancy    Concerns: Risk to fetus of venous emboli formed     during decompression is unknown

Mental health conditions  Developmental delay  History of drug or alcohol abuse  History of psychosis  Use of psychotropic medications   Concerns: Patient must be mentally able to learn the     information vital to diving safety and react appropriately     as instructed

Mental health contraindications  Claustrophobia  Agoraphobia  Active psychosis  Untreated panic disorder  Drug or alcohol abuse   Concerns: Diver would be ill-equipped to handle     stressful situations in diving

Otolaryngologic conditions   Recurrent otitis externa   Significant obstruction of external auditory canal   Eustachian tube dysfunction   Recurrent otitis media or sinusitis   History of tympanic membrane perforation, tympanoplasty,      mastoidectomy   Significant conductive or sensorineural hearing loss   Facial nerve paralysis not associated with barotrauma   History of round window rupture or inner ear barotrauma     Concerns: Any of these conditions is likely to affect the      ability to equalize pressure of sinuses or ears during      ascent and descent and to increase the possibility of      barotraumas   Full prosthedontic devices   History of mid-face fractures   Unhealed oral surgical sites   Therapeutic radiation to the head or neck   Temporomandibular joint dysfunction     Concerns: These conditions may affect the manner in which      the mouthpiece fits or is held or the way the mask fits

Otolaryngologic contraindications   Monomeric tympanic membrane   Open tympanic membrane perforation   Stapedectomy   Tube myringotomy   Ossicular chain surgery   Inner ear surgery   Facial nerve paralysis due to barotrauma   Inner ear disease other than presbycusis   Laryngectomy or partial laryngectomy   Tracheostomy   Uncorrected laryngocele   History of vestibular decompression sickness

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di tayangkan ulang oleh dr.Erick Supondha (hyperbaric&Diving medicine Consultant) Jakarta Indonesia 021 99070050 ,http//:wwwindodivinghealth.com