“Know what you are eating.”

Seafood poisonings are illnesses caused by the ingestion of a natural toxin present in seafood. This toxicity can be inherent to the species as is the case in fugu and other tetraodontiforms, or toxicity can result from external contamination such as shellfish poisonings or ciguatera. Many gastrointestinal issues commonly attributed to seafood poisonings are often actually result of gastrointestinal infections caused by ingestion of harmful bacteria, parasites or viruses, and for that reason they are not included in this text.

In this chapter, we will discuss ichthyosarcotoxism, a form of food poisoning resulting from ingestion of fish flesh containing natural toxins. Ichthyosarcotoxism originates from the Greek words ichthyo (fish), sarx (flesh) and toxism (intoxication or poisoning). The three main ichthyosarcotoxisms are ciguatera, scombroid fish poisoning and tetrodotoxism. We will also cover shellfish-related intoxications. Since shellfish are bivalve mollusks not fish, these cases cannot be called an ichthyosarcotoxism.

Learn more about:

• Ciguatera
• Keracunan Ikan Scombroid
• Keracunan Red Tide & Kerang

Ciguatera

Ciguatera poisoning occurs when contaminated reef fish are consumed. Specific reef fish bioaccumulate toxins produced by microorganisms in their diet. Though ciguatera intoxication should not be fatal, there is no treatment, so it is prudent to become familiar with potentially toxic species to avoid this poisoning.

Source of Intoxication

Ciguatera is caused by ingesting fish contaminated with certain toxins collectively known as ciguatoxins, which are produced by photosynthetic unicellular dinoflagellates (Gambierdiscus toxicus) that are part of phytoplankton. Dinoflagellates are epiphytes, which means they live on macro algae and dead coral surfaces. Small reef fish feed on these corals and macro algae accidentally ingesting these dinoflagellates. As these smaller fish are eaten by larger predators, the toxin is transmitted up the food chain and accumulates in the tissues of top predators through a process known as bioaccumulation. Human poisoning can potentially occur when any of the fish involved in this chain are consumed, but poisoning is much more likely when eating the larger predators.

Species known to be a source of intoxication include barracudas, snappers, moray eels, parrotfish, groupers, triggerfish and amberjacks, but other species have been known to cause occasional outbreaks. Ciguatera toxins rarely contaminate pelagic fish such as tuna, marlins, dolphinfish or other ray-finned fish. Ciguatoxin can be found around the world in the tropical reef belt between 35 degrees north latitude and 35 degrees south latitude.

Epidemiologi

Ciguatera is probably the most common type of marine food poisoning. It is endemic in Australia, the Caribbean and the South Pacific islands. Ciguatera cases should be naturally limited to these areas, but due to commercial imports, cases of ciguatera have been reported in areas like St. Louis, Missouri and New York City.

Approximately 50,000 reported cases of ciguatera poisoning occur annually worldwide. Epidemiological data regarding ciguatera poisoning is challenging to collect; because of the wide array of symptoms, ciguatera is often misdiagnosed or undiagnosed. People in endemic areas often disregard medical evaluation, while imported cases probably go undiagnosed or unreported, because physicians outside of endemic regions may be unfamiliar with symptoms of a tropical toxin. Recent studies have suggested that the incidence of this illness is continuing to increase, though this might be due to increased reporting rather than an increased occurrence of the disease.

Tanda dan Gejala

Toxicity depends on exposure and dose (how much is ingested). Symptom onset usually occurs two to six hours after ingestion. Symptoms can last for weeks to years, and in some cases may lead to long-term disability.

Signs and symptoms can be highly variable, but typically include neurological or gastrointestinal manifestations; about 80 percent of patients showing varying degrees of impairment in both systems. The most common manifestations include:

• Gastrointestinal symptoms such as abdominal pain and gastroenteritis, nausea, vomiting or diarrhea. These initial symptoms typically resolve without intervention within a few hours.
• Neurological symptoms including paresthesia (tingling and numbness), ataxia (uncoordinated muscle movements) and vertigo. Severe cases may include cold allodynia (temperature reversal), a burning sensation upon contact with cold objects. Neurological symptoms may persist and are occasionally misdiagnosed as multiple sclerosis. In patients with a recent history of diving, muscular weakness and pain, these neurological symptoms can also be confounder for decompression illness.
• Skin itching that can persist for weeks and worsen as a result of activities that increase skin temperature like exercise and alcohol consumption.

Pencegahan

• Avoid consuming fish species commonly associated with ciguatera include barracuda, grouper, snapper, parrotfish, moray eels, triggerfish and amberjacks.
• Ciguatoxin is odorless, tasteless and heat-resistant—it will not taste different, and cooking will not prevent intoxication.
• While the whole fish will contain toxins, the highest concentrations are typically found in the liver, intestines and gonads.

Keracunan Ikan Scombroid

Scombroid fish poisoning is a foodborne illness that results from eating spoiled fish containing high amounts of histamine.

Source of Intoxication

There are many different species of fish that can be involved in scombroid poisoning, including mackerel, tuna, bonito, albacore, sardines, anchovies, mahi-mahi, amberjacks, marlin and herrings.

If scombroids are poorly refrigerated after being caught, the fish will begin to decompose, and bacteria from the fish’s gastrointestinal tract will invade its flesh. Many fish contain a significant amount of an amino acid called histidine in their flesh. When decomposition begins, the bacteria from the gastrointestinal tract breaks histidine down into histamine (a small nitrogen compound involved in regulation of immune reactions and inflammatory responses). While ingestion of histidine is harmless, ingestion of large quantities of histamine can mimic an allergic reaction.

Epidemiologi

In the United States and Europe, scombroid fish poisoning accounts for up to 40 percent of seafood-borne illness outbreaks. Between 1998 and 2002, there were 167 reported outbreaks in the United States affecting 703 persons with no fatalities. Scombroid fish poisoning can happen anywhere in the world where susceptible fish are harvested. This poisoning is more common when consuming fish caught recreationally or from small-scale operations; it rarely occurs in highly regulated fish harvests.

Tanda dan Gejala

Ingestion of large quantities of histamine can mimic an allergic reaction. Symptom onset may range from minutes after consumption to up to two hours and typically resolves within 24 hours.

Due to its resemblance to an allergic reaction combined with poor knowledge of intoxication, scombroid fish poisoning is commonly misdiagnosed as a seafood allergy. Anyone showing signs and symptoms compatible with allergic reactions should seek an immediate medical evaluation as allergic and allergic-like reactions can be life threatening.

Pencegahan

• Scombroid fish poisoning is entirely preventable by immediately storing fresh fish in coolers or ice containers away from direct sunlight. The Centers for Disease Control and Prevention (CDC) recommends temperatures below 40°F (4.4°C) at all points during the fish supply chain.
• Affected fish may have a peppery taste, but normal taste does not guarantee safety.
• Histamine is heat stable, so cooking does not prevent scombroid fish poisoning.

Perawatan

As opposed to genuine allergic reactions, where the source of histamine is internal, treatment for scombroid fish poisoning does not require the use of corticosteroids or adrenaline (epinephrine). Instead, scombroid fish poisoning responds very well to oral antihistamines, typically showing positive results within 10 to 15 minutes.

Never assume oral antihistamines are enough to control a presumed scombroid fish poisoning on your own. Always seek for professional medical evaluation and let a medical doctor decide over treatment and best course of action.

Keracunan Red Tide & Kerang

Red tide is a colloquial term for a specific phenomenon known as harmful algal bloom. Occasionally, large concentrations of aquatic microorganisms naturally bloom in coastal areas. The rapid accumulation of algal blossom can be significant enough to cause a green, red or brown discoloration of estuarine and freshwater environments.

Scientists discourage the term red tide, because these phenomena are unrelated to tidal water movements and may not necessarily be red in color or present any discoloration at all. Instead, when these algal blooms are associated with potentially harmful toxins, a more precise and favored terminology is harmful algal bloom (HAB).

Negative Impact on Ecosystems

Among the involved microorganisms certain species of phytoplankton may be present, which can produce harmful natural toxins that can become concentrated in tissues of filter feeders like shellfish and other mollusks and crustaceans. The whole food chain may be affected, and millions of fish may die as a result.

Danger to Humans

These toxins can affect commercial fisheries and represent a public health threat. People who consume contaminated shellfish may suffer a variety of shellfish poisonings, some of which are potentially lethal. Hazards related to HAB may not be limited to shellfish consumption, so avoid harvesting any type seafood on areas where HAB is known to have endemic outbreaks.

Shellfish Poisonings

Shellfish are bivalve (two-part shells) mollusks that capture nutrients by filtering water. During this process, these filter feeders can accumulate toxins and other contaminants. When humans consume these bivalves, they may be poisoned. These toxins are water-soluble and heat- and acid-stable—they are unaltered by ordinary cooking methods. Shellfish poisonings are a group of four different syndromes caused by eating bivalve mollusks contaminated with toxins produced by microscopic algae.

SYNDROMES

There are four different types of shellfish poisonings that are primarily associated with mollusks such as mussels, clams, oysters and scallops.

PARALYTIC SHELLFISH POISONING (PSP)

These mollusks can accumulate a toxin called saxitoxin, which is produced by phytoplankton (dinoflagellates, diatoms and cyanobacteria). Some shellfish remain toxic for several weeks, while others can store the toxin for up to two years.

PSP blooms are associated with harmful algal blooms, which can occur in almost all oceans. PSP can be fatal, particularly in children. Symptoms can appear a few minutes after ingestion and include nausea, vomiting, diarrhea, abdominal cramps, numbness or burning around the mouth, gums, tongue and progressing to the neck, arms, legs and toes. Other symptoms may include dry mouth, shortness of breath, slurred speech and loss of consciousness. Signs of toxicity and mortality are also seen in wild animals.

AMNESIC SHELLFISH POISONING (ASP)

This rare syndrome is caused by consuming shellfish contaminated with a toxin called domoic acid produced by certain marine diatoms.

Symptoms can appear 24 hours after ingestion of contaminated mollusks and may include nausea, vomiting, diarrhea, abdominal cramps and hemorrhagic gastritis. Neurological signs are severe and can take up to three days to develop. Neurological signs include dizziness, disorientation, visual disturbances, short-term memory loss, motor weakness, seizures, increased respiratory secretions and life-threatening dysrhythmias (irregular heartbeat). Death is rare. Resulting conditions due to permanent damage to the central nervous system may include short-term memory loss and peripheral neuropathy (weakness, numbness or pain as a result of nerve damage).

DIARRHEAL SHELLFISH POISONING (DSP)

Certain dinoflagellates produce a toxin known as okadaic acid that can cause a diarrheic syndrome. This toxin can damage the intestinal mucous membrane making it very permeable to water, which causes significant diarrhea as well as nausea, vomiting and abdominal cramps.

Symptoms can strike within a few minutes to an hour of ingesting contaminated shellfish and can last for about one day. No life-threatening symptoms have ever been recorded, but serious dehydration may occur.

NEUROTOXIC SHELLFISH POISONING (NSP)

NSP is caused by a toxin called brevetoxin, naturally produced by a dinoflagellate known as Karenia brevis. Brevetoxin can cause a variety of neurological symptoms very similar to ciguatera. NSP is generally not life threatening, but hospitalization is recommended until all other possible causes have been ruled out. In the United States and the Gulf of Mexico, a blossom of Karenia brevis usually causes the phenomena known as HAB.

Pencegahan

HABs occur throughout the world, killing millions of marine animals and affecting fisheries. Before harvesting your own seafood from coastal areas, research where HABs may occur and avoid consuming self-caught shellfish and fish from areas known to have HABs. Commercial fisheries tend to be safer than small scale artisanal harvesters.

The National Oceanic and Atmospheric Administration (NOAA) has a NOAA HAB (Red Tide) Watch page on Facebook. This system provides an operational forecast for harmful algal blooms. For those not on Facebook, NOAA’s Tides & Currents portal also provides an Operational Forecast System for HABs.

The Florida Fish and Wildlife Conservation Commission offers an online resource with a current map of Red Tide counts in the state of Florida.

Berikutnya Chapter 4 – Appendix >

“Safety is a consequence of education.”

Divers Alert Network encourages divers from all levels of certification to get first aid training so they are prepared to respond to diving injuries, including marine life injuries. The following chapter details some of the first aid techniques and treatments mentioned throughout the book including thermolysis, antivenoms and the pressure immobilization technique. However, it is important to emphasize that reading and understanding these materials is not a substitute for first aid training.

If you have not been formally trained, DAN highly recommends you find a qualified instructor. To find a First Aid for Hazardous Marine Life Injuries Instructor, visit the DAN Instructor Directory.

In this chapter, you’ll learn about:

• Termolisis
• Anti Bisa
• Teknik Imobilisasi Tekanan

Termolisis

Thermolysis describes the use of heat to break down substances (thermo meaning temperature, and lysis meaning breakdown or destruction). This is often accomplished by immersing the affected area in hot water.

Proteins are essential organic compounds that perform a vast array of functions within living organisms. Most life forms live in temperatures below 122°F (50°C).

Above this temperature, their proteins will suffer an irreversible unfolding of their three-dimensional biomolecular structure. This process has damaging consequences to their function and is called protein denaturation. Application of heat may denature venoms that are comprised of proteins, thus eliminating their effect or reducing their potency.

Technique

The standard recommendations for toxin denaturation as a first aid measure call for immersing the affected area in hot freshwater with an upper limit of 113°F (45°C) for 30 to 90 minutes. This may work reasonably well when the toxin inoculation is skin deep, like a jellyfish sting, but will be less effective when toxins have been inoculated by means of deeper puncture wounds, as is the case of lionfish spines. Though quick reasoning could call for increasing the temperature, applying higher temperatures at skin level in an attempt to reach the desired temperature at a deeper level poses an unacceptable risk of burning the skin. In addition, vasodilatation caused by exposure to elevated temperatures may expedite the onset of absorption and of systemic effects.

Each case is unique and requires some estimation of the depth to which the venom was injected; for superficial inoculations, application of heat might be useful to manage pain and denature toxins, whereas for deeper inoculations, heat is for pain management only.

Risk Considerations

If you attempt to use thermolysis as a first aid measure, minimize the risk of local tissue damage to the injured diver by testing the water on yourself first on the same area that the diver is injured. Use the hottest temperatures you can tolerate and avoid scalding. Do not rely on the victim’s assessment, as intense pain may impair his ability to evaluate temperature tolerability.

Antivenom (Antivenin, Antivenene)

Antivenom is a biological product used in the treatment of venomous bites or stings (not to be confused with antidote). Though it is rare, recreational scuba divers might incur a venomous sting from certain marine life, such as stonefish or box jellyfish, necessitating the use of antivenom. Venomous bites, such as those from sea snakes, are even more uncommon.

What is Antivenom?

Antivenoms are blood-derived biological products developed by injecting an animal—typically a horse, goat or sheep—with sublethal doses of venom. The animal will gradually develop antibodies against the venom, which can then be extracted from its blood as a serum to be administered to humans. Like most blood-derived products, antivenoms require an unbroken cold chain (proper refrigeration from production through storage until administration).

Risks Considerations

Though generally not a concern for first responders, administering antivenoms is not free of risk. Intravenous administration of animal serums can cause anaphylactic shock in susceptible individuals.

What About Antivenom Autoinjectors?

Occasionally, DAN is asked about autoinjectors for antivenoms. Conceptually, these antivenom autoinjectors would work similarly to the way epinephrine autoinjectors (like EpiPen®) work for intramuscular administration. Though it is certainly a compelling idea, antivenoms are much more complex blood-derived products than epinephrine. As such, they have a much shorter shelf life and require an unbroken cold chain. In addition, antivenoms are administered intravenously, a skill which is beyond first aid responders. These limiting factors make this idea relatively impractical for field operation.

Teknik Imobilisasi Tekanan

The pressure immobilization technique is a first aid skill intended to contain venom within the bitten area and prevent it from moving into central circulation, where the venom could affect vital organs. The technique consists of pressure to prevent lymphatic drainage and immobilization to prevent venous return (blood flow back to the heart) caused by the pumping action of skeletal muscle.

Technique

Use an elastic bandage and splinting to administer proper pressure and immobilization. An inelastic cloth is not ideal as it is difficult to achieve optimal pressure.

1. Begin bandaging a few inches above the bite site (between the bite and the heart).
2. Wind the bandage around the limb with overlapping turns moving up the limb and then back down past the bite site.
3. The wrap should be tight enough to administer pressure, but you should still have normal feeling, color and a palpable pulse.
4. Use a splint or suitable substitute to immobilize the limb.
5. If possible, hold upper extremities with a sling.

Kesehatan kardiovaskular adalah komponen penting dari keselamatan scuba diving. Namun, kesehatan jantung dapat memburuk secara bertahap seiring bertambahnya usia dan dapat membahayakan penyelam. Buku ini mencakup konsep dasar fungsi jantung normal dalam aktivitas fisik, persyaratan kebugaran fisik menyelam, bagaimana penyakit jantung dapat mempengaruhi kebugaran menyelam dan bagaimana penyelam dapat mempertahankan kapasitas kebugaran mereka.

In this book, you’ll learn about:

• Chapter 1 – Basics of Your Heart & Circulatory System
  • Bagaimana Menyelam Mempengaruhi Kesehatan dan Sistem Peredaran Darah Anda
  • Kesehatan Jantung dan Risiko Kematian Saat Menyelam
  • Memahami Konsep Kapasitas Latihan Aerobik
  • Efek Penuaan pada Sistem Kardiovaskular Anda
  • Menghitung Intensitas Aktivitas Fisik
  • Rekomendasi Aktivitas Fisik
  • Menempatkan Risiko dan Manfaat Aktivitas Fisik dalam Perspektif
• Chapter 2 – Risk Factors for Cardiovascular Disease
  • Gambaran Umum Faktor Risiko Kardiovaskular
  • Hipertensi
  • Hiperlipidemia
  • Kelebihan Berat Badan dan Obesitas
  • Sindrom Metabolik
• Chapter 3 – Structural Anomalies of the Heart
  • Gangguan Katup (Valvular Disorders)
  • Prolaps Katup Mitral
  • Patent Foramen Ovale
• Chapter 4 – Ischemic Heart Disease
  • Atherosclerosis
  • Myocardial Infarction
  • Coronary Artery Bypass Grafts
  • Isu Khusus pada Wanita
• Chapter 5 – Arrhythmias
  • Sekilas Tentang Aritmia
  • Syncope
  • Extrasystole
  • Atrial Fibrillation
  • Serangan Jantung Mendadak
  • Masalah yang Melibatkan Alat Pacu Jantung Tertanam (Implan)
• Chapter 6 – Pulmonary and Venous Disorders
  • Deep Vein Thrombosis
  • Emboli Paru
  • Immersion Pulmonary Edema
• Chapter 7 – Issues Involving Cardiovascular Drugs
  • Antiplatelet dan Antikoagulan
  • Statins
  • Antihipertensi
  • Antiaritmia
• Bacaan dan Sumber Lebih Lanjut

Kredit:

Managing Editor: Petar Denoble, MD, DSc
Editor: James Chimiak, MD

“By 2050, it is estimated that atrial fibrillation (AFib) will affect between 5.6 million and 12 million Americans.”

The electrical wiring of your heart — which controls the rate at which your heart beats, every minute, hour and day, 365 days a year — is one of the most sophisticated and enduring pieces of nature’s engineering. However, there are some irregularities that can occur in that wiring as well as damage that can be caused by disease, all of which can cause symptoms and increase the risk of premature death. Divers, and any physicians who treat them, should be familiar with arrhythmias and their effects on the safety of scuba divers.

In this chapter, you’ll learn about:

• Sekilas Tentang Aritmia
• Syncope
• Extrasystole
• Atrial Fibrillation
• Serangan Jantung Mendadak
• Masalah yang Melibatkan Alat Pacu Jantung Tertanam (Implan)

Sekilas Tentang Aritmia

The term “arrhythmia” (or, sometimes, “dysrhythmia”) means an abnormal heartbeat. It is used to describe manifestations ranging from benign, harmless conditions to severe, life-threatening disturbances of the heart’s rhythm.

A normal heart beats between 60 and 100 times a minute. In well-trained athletes, or even select nonathletic individuals, the heart may beat at rest as slowly as 40 to 50 times a minute. Even entirely healthy, normal individuals experience occasional extra beats or minor changes in their heart’s rhythm. These can be caused by drugs (such as caffeine) or stress or can occur for no apparent reason. Arrhythmias become serious only when they are prolonged or when they do not result in proper contraction of the heart.

Physiologically significant extra heartbeats may originate in the upper chambers of the heart (this is called “supraventricular tachycardia”) or in the lower chambers of the heart (this is called “ventricular tachycardia”). The cause of these extra beats may be a short circuit or an extra conduction pathway in the heart’s wiring, or it may be the result of some other cardiac disorder. People who have episodes or periods of rapid heartbeat are at risk of losing consciousness during such events. Other people have a fairly stable arrhythmia (such as “fixed atrial fibrillation”) but in conjunction with additional cardiovascular disorders or other health problems that exacerbate the effect of their rhythm disturbance. A too-slow heartbeat (or a heart blockage) may cause symptoms, too.

Efek pada Menyelam

Serious arrhythmias, such as ventricular tachycardia and many types of atrial arrhythmia, are incompatible with diving. The risk for any person who develops an arrhythmia during a dive is, of course, losing consciousness while underwater. Supraventricular tachycardia, for example, is unpredictable in its onset and may even be triggered simply by immersing one’s face in cold water. Anyone who has had more than one episode of this type of arrhythmia should not dive.

Kebanyakan aritmia yang memerlukan pengobatan juga mendiskualifikasi individu yang terkena dari penyelaman yang aman. Pengecualian dapat dibuat berdasarkan kasus per kasus dengan berkonsultasi dengan ahli jantung dan petugas medis selam.

Seseorang yang memiliki aritmia jantung memerlukan evaluasi medis lengkap oleh ahli jantung sebelum melakukan penyelaman. Dalam beberapa kasus, studi elektrofisiologi dapat mengidentifikasi jalur konduksi yang abnormal, dan masalahnya dapat diperbaiki. Baru-baru ini, dokter dan peneliti telah menentukan bahwa orang dengan beberapa aritmia (seperti jenis tertentu dari sindrom Wolff-Parkinson-White, yang ditandai dengan jalur listrik ekstra) dapat dengan aman berpartisipasi dalam menyelam setelah evaluasi menyeluruh oleh ahli jantung. Juga, dalam kasus tertentu, orang dengan aritmia atrium yang stabil (seperti fibrilasi atrium tanpa komplikasi) dapat menyelam dengan aman jika ahli jantung menentukan bahwa mereka tidak memiliki masalah kesehatan signifikan lainnya.

Syncope

Sinkop adalah hilangnya kesadaran secara tiba-tiba yang diikuti dengan pemulihan yang relatif cepat. Penyebab sinkop berkisar dari yang relatif jinak hingga mengancam jiwa. Ini jarang diabaikan dan biasanya memicu kunjungan ke profesional medis.

Sinkop yang terjadi di dalam atau di sekitar air menimbulkan tantangan tertentu. Tenggelam sering terjadi ketika seorang penyelam kehilangan kesadaran dan tetap berada di dalam air. Respon cepat diperlukan untuk membawa penyelam yang tidak sadar ke permukaan dan mencegah kematian. Sinkop juga dapat terjadi saat keluar dari air, karena faktor-faktor seperti pengerahan tenaga, dehidrasi, dan kembalinya volume darah ke ekstremitas bawah secara normal.

Respon awal terhadap sinkop harus fokus pada ABC bantuan hidup dasar: jalan napas, pernapasan, dan sirkulasi. Bantuan kehidupan jantung lanjutan mungkin diperlukan. Seringkali, menempatkan pasien sinkop dengan posisi telentang di lingkungan yang sejuk akan dengan cepat mengembalikan kesadaran mereka. Jika sinkop terjadi setelah penyelaman, penting untuk mempertimbangkan penyakit dekompresi, inflasi paru yang berlebihan, dan edema paru imersi selain penyebab umum dari kondisi tersebut. Meskipun sinkop dan henti jantung mengakibatkan hilangnya kesadaran, mereka biasanya dapat dibedakan dengan jelas.

The list of possible causes of syncope is extensive, but a good medical history can help eliminate the majority of them. The patient’s age, heart rate, family history, medical conditions and medications are key in identifying the cause. If syncope is accompanied by convulsions (known as “tonic-clonic movements”), it may have been precipitated by a seizure. If it occurs upon exertion, a serious cardiac condition may be preventing the heart from keeping up with the demands of the physical activity; chest pain may be associated with this type of syncope. If standing up quickly results in syncope, that points to a cause known as “orthostatic hypotension.” And pain, fear, urination, defecation, eating, coughing or swallowing may cause a variation of the condition known as “reflex syncope.”

A medical evaluation after an incident of syncope should include a thorough history and physical — plus interviews with witnesses who observed the individual’s collapse and who can accurately relay the sequence of events. A few cases may require more extensive investigation, and some result in no conclusion.

Efek pada Menyelam

While a medical evaluation is being conducted, it is recommended that the affected individual refrain from any further diving. The cause of a given syncopal episode can be elusive but must be pursued — especially if the individual hopes to return to diving. Once the underlying factors have been determined, a diving medical officer and appropriate specialists should consider whether diving can be resumed safely.

Extrasystole

Heart beats that occur outside the heart’s regular rhythm are known as “extrasystoles.” They often arise in the ventricles, in which case they are referred to as “premature ventricular contractions” or sometimes “premature ventricular complexes,” abbreviated as PVCs. The cause of such extra beats can be benign or can result from serious underlying heart disease.

PVC umum bahkan pada individu yang sehat; mereka telah dicatat pada 75 persen dari mereka yang menjalani pemantauan jantung berkepanjangan (setidaknya selama 24 jam, yaitu). Insiden PVC juga meningkat seiring bertambahnya usia; mereka telah dicatat pada lebih dari 5 persen individu berusia lebih dari 40 tahun yang menjalani elektrokardiogram (atau EKG, tes yang biasanya membutuhkan waktu kurang dari 10 menit untuk dilakukan). Pria tampaknya lebih terpengaruh daripada wanita.

The extrasystole itself is usually not felt. It is followed by a pause — a skipped beat — as the heart’s electrical system resets itself. The contraction following the pause is usually more forceful than normal, and this beat is frequently perceived as a palpitation — an unusually rapid or intense beat. If extrasystoles are either sustained or combined with other rhythm abnormalities, affected individuals may also experience dizziness or lightheadedness. Heart palpitations and the sensation of missed or skipped beats are the most common complaints of those who seek medical care for extrasystole.

A medical examination of the condition begins with a history and physical and should also include an ECG and various laboratory tests, including the levels of electrolytes (such as sodium, potassium and chloride) in the blood. In some cases, doctors may recommend an echocardiogram (an ultrasound examination of the heart), a stress test and/or the use of a Holter monitor (a device that records the heart’s electrical activity continuously for a 24- to 48-hour period). Holter monitoring may uncover PVCs that are unifocal — that is, they originate from a single location. Of greater concern are multifocal PVCs — those that arise from multiple locations — as well as those that exhibit specific patterns known R-on-T phenomenon, bigeminy and trigeminy.

If serious structural disorders, such as coronary artery disease or cardiomyopathy (a weakening of the heart muscle), can be ruled out — and the patient remains asymptomatic — the only “treatment” required may be reassurance. But for symptomatic patients, the course is less clear, as there is controversy regarding the effectiveness of the available treatment options. Two drugs commonly used to treat high blood pressure — beta blockers and calcium channel blockers — have been used in patients with extrasystole with some success. Antiarrhythmics have also been prescribed for extrasystole but have met with mixed reviews. A procedure known as cardiac ablation may be an option for symptomatic patients, if the location where their extra beats arise can be identified; the procedure involves threading tiny electrodes into the heart via catheters, then zapping the affected locations to rewire the heart’s faulty circuits.

Efek pada Menyelam

Meskipun PVC hadir dalam persentase besar pada individu normal, mereka telah terbukti meningkatkan mortalitas dari waktu ke waktu. Jika PVC terdeteksi, penting untuk diselidiki dan kondisi terkait yang diketahui harus dikesampingkan. Penyelam yang mengalami PVC dan ditemukan juga memiliki penyakit arteri koroner atau kardiomiopati akan menempatkan diri mereka pada risiko yang signifikan jika mereka terus menyelam. Penyelam yang didiagnosis dengan fenomena R-on-T, takikardia ventrikel yang tidak berkelanjutan atau PVC multifokal juga harus menahan diri untuk tidak menyelam. Penyelam yang mengalami PVC tetapi tetap tanpa gejala mungkin dapat mempertimbangkan untuk kembali menyelam; individu tersebut harus mendiskusikan dengan ahli jantung mereka temuan medis mereka, keinginan mereka untuk terus menyelam dan pemahaman yang jelas tentang risiko yang terlibat.

Atrial Fibrillation

Atrial fibrillation (AF or AFib), the most common form of arrhythmia, is characterized by a fast and irregular heartbeat. It results from a disturbance of the electrical signals that normally make the heart contract in a controlled rhythm. Instead, chaotic and rapid impulses cause uncoordinated atrial filling and ventricle pumping action. This leads to a decrease in overall cardiac output, which can affect one’s exercise capacity or even result in unconsciousness. In addition, AF causes blood to pool in the atria, which promotes the formation of blood clots that may break loose and enter the circulatory system; if this occurs, it may result in a stroke.

Studi AS baru-baru ini menunjukkan peningkatan insiden AF secara keseluruhan serta perbedaan ras yang signifikan dalam prevalensinya. Risiko seumur hidup AF (pada usia 80 tahun) baru-baru ini ditemukan menjadi 21 persen pada pria kulit putih dan 17 persen pada wanita kulit putih tetapi hanya 11 persen pada orang Afrika-Amerika dari kedua jenis kelamin. Pada tahun 2050, diperkirakan AF akan mempengaruhi antara 5,6 juta dan 12 juta orang Amerika. Angka-angka ini signifikan, karena AF dikaitkan dengan risiko stroke iskemik empat kali lipat hingga lima kali lipat lebih tinggi. Individu dengan AF, setelah disesuaikan dengan faktor risiko lain, juga memiliki risiko demensia dua kali lipat lebih tinggi.

The most common causes of AF are hypertension and coronary artery disease. Additional causes include a history of valvular disorders, hypertrophic cardiomyopathy (a thickening of the heart’s muscle), deep vein thrombosis (DVT), pulmonary embolism, obesity, hyperthyroidism (also called “overactive thyroid”), heavy alcohol consumption, an imbalance of electrolytes in the blood, cardiac surgery and heart failure.

Some people with AF experience no symptoms and are unaware they have the condition until it’s discovered during a physical examination. Others may experience symptoms such as the following:

• Palpitasi (detak jantung berpacu, tidak nyaman, tidak teratur atau sensasi flip-flopping di dada)
• Kelemahan
• Penurunan kemampuan untuk berlatih
• Kelelahan
• Pusing
• Pening
• Kebingungan
• Sesak nafas
• Nyeri dada

Terjadinya dan durasi fibrilasi atrium biasanya jatuh ke dalam salah satu dari tiga pola:

• Occasional (or “paroxysmal”): Gangguan ritme dan gejalanya datang dan pergi, berlangsung selama beberapa menit hingga beberapa jam, dan kemudian berhenti dengan sendirinya. Peristiwa semacam itu dapat terjadi beberapa kali dalam setahun, dan frekuensinya biasanya meningkat seiring waktu.
• Tetap: The heart’s rhythm doesn’t go back to normal on its own, and treatment — such as an electrical shock or medication — is required to restore a normal rhythm.
• Permanen: The heart’s rhythm can’t be restored to normal. Treatment may be required to control the heart rate, and medication may be prescribed to prevent the formation of blood clots.

Setiap kasus baru AF harus diselidiki dan penyebabnya ditentukan. Investigasi dapat mencakup pemeriksaan fisik; elektrokardiogram; pengukuran kadar elektrolit, termasuk magnesium; tes hormon tiroid; ekokardiogram; hitung darah lengkap; dan/atau rontgen dada.

Treating the underlying cause of AF can help control the fibrillation. Various medications, including beta blockers, may help regulate the heart rate. A procedure known as cardioversion — which can be performed with either a mild electrical shock or medication — may prompt the heart to revert to a normal rhythm; before cardioversion is attempted, it is essential to ensure that a clot has not formed in the atrium. Cardiac ablation, which is described in the “Extrasystole” section, may also be used to treat AF. In addition, anticoagulant drugs are often prescribed for individuals with AF to prevent the formation clots and thus reduce their risk of stroke. It is also of note that the neurological effects of an embolic stroke associated with AF can sometimes be confused with the symptoms of decompression sickness.

Efek pada Menyelam

A thorough medical examination should be conducted to identify the underlying cause of the atrial fibrillation. It is often the underlying cause that is of most concern regarding fitness to dive. But even atrial fibrillation itself can have a significant impact on cardiac output and therefore on maximum exercise capacity. Individuals who experience recurrent episodes of symptomatic AF should refrain from further diving. The medications often used to control atrial fibrillation can present their own problems, by causing other arrhythmias and/or impairing the individual’s exercise capacity. It is essential that anyone diagnosed with AF have a detailed discussion with a cardiologist before resuming diving.

Serangan Jantung Mendadak

Sudden cardiac arrest (SCA) — a cessation of the heart’s beating action, with little or no warning — is an acute medical emergency. During the arrest, blood stops circulating to the body’s vital organs, including the brain, the kidneys and the heart itself. Cut off from oxygen, these organs die within minutes. If the arrest is not corrected quickly, the affected individual will not survive.

The causes of SCA include myocardial infarction (heart attack), heart failure, drowning, coronary artery disease, electrolyte abnormalities, drugs, abnormalities in the heart’s electrical conduction system, cardiomyopathy (a weakening of the heart muscle) and embolism (a clot that has lodged in a major vessel).

SCA menyumbang 450.000 kematian di Amerika Serikat setiap tahun dan 63 persen kematian jantung di Amerika berusia lebih dari 35 tahun. Risiko kematian jantung mendadak pada orang dewasa meningkat sebanyak enam kali lipat dengan bertambahnya usia, sejajar dengan meningkatnya insiden penyakit jantung iskemik. Risiko SCA lebih besar pada mereka yang memiliki penyakit jantung struktural, tetapi pada 50 persen kematian jantung mendadak, korban tidak memiliki kesadaran akan penyakit jantung, dan pada 20 persen otopsi yang dilakukan setelah kematian tersebut, tidak ditemukan kelainan struktural kardiovaskular.

Meskipun biasanya ada sedikit peringatan sebelum serangan jantung mendadak, kadang-kadang individu mungkin mengalami pusing, kesulitan bernapas, palpitasi atau nyeri dada.

Perawatan segera harus difokuskan pada pemulihan sirkulasi dengan cepat menggunakan kompresi dada atau CPR dan defibrilasi. Setelah resusitasi, korban harus dibawa ke rumah sakit sesegera mungkin. Perawatan selanjutnya dapat terdiri dari upaya untuk menghilangkan penyebab yang mendasari penangkapan melalui pemberian obat-obatan, pembedahan atau penggunaan perangkat listrik yang ditanamkan.

Strategi pencegahan termasuk belajar mengenali tanda-tanda peringatan SCA, jika terjadi; mengidentifikasi, menghilangkan, atau mengendalikan faktor risiko apa pun yang dapat memengaruhi Anda; dan menjadwalkan pemeriksaan fisik secara teratur, serta pengujian yang sesuai, bila diindikasikan.

Efek pada Menyelam

Penyelam dengan gejala penyakit kardiovaskular harus dievaluasi oleh ahli jantung dan spesialis kedokteran selam mengenai partisipasi mereka yang berkelanjutan dalam penyelaman. Pada individu tanpa gejala, risiko SCA dapat dievaluasi dengan menggunakan faktor risiko kardiovaskular yang diketahui seperti merokok, tekanan darah tinggi, kolesterol tinggi, diabetes, kurang olahraga, dan kelebihan berat badan. Misalnya, orang yang merokok memiliki dua setengah kali risiko menderita kematian jantung mendadak daripada bukan perokok.

Masalah yang Melibatkan Alat Pacu Jantung Tertanam (Implan)

A pacemaker is a small battery-operated device that helps an individual’s heart beat in a regular rhythm. It does this by generating a slight electrical current that stimulates the heart to beat. The device is implanted under the skin of the chest, just below the collarbone, and is hooked up to heart with tiny wires that are threaded into the organ through its major vessels. In some individuals, the heart may need only intermittent help from the pacemaker, if the pause between two beats becomes too long. In others, however, the heart may depend completely on the pacemaker for regular stimulation of its beating action.

Efek pada Menyelam

Setiap kasus yang melibatkan alat pacu jantung harus dievaluasi secara individual. Dua faktor yang paling penting untuk diperhitungkan adalah sebagai berikut:

1. Mengapa individu tersebut bergantung pada alat pacu jantung?
2. Is the individual’s pacemaker rated to perform at depths (in other words, pressures) compatible with recreational diving — plus an added margin of safety?

Alasan untuk faktor kedua adalah bahwa alat pacu jantung ditanamkan di jaringan tepat di bawah kulit dan dengan demikian terkena tekanan lingkungan yang sama dengan penyelam selama menyelam. Untuk penyelaman yang aman, alat pacu jantung harus dinilai untuk tampil pada kedalaman setidaknya 130 kaki (40 meter) dan juga harus beroperasi dengan baik selama kondisi perubahan tekanan yang relatif cepat, seperti yang akan dialami selama naik dan turun.

As with any medication or medical device, the underlying problem that led to the implantation of the pacemaker is the most significant factor in determining someone’s fitness to dive. The need to have a pacemaker implanted usually indicates a serious disturbance in the heart’s own conduction system.

Jika gangguan muncul dari kerusakan struktural pada otot jantung itu sendiri, seperti yang sering terjadi ketika seseorang menderita serangan jantung yang parah, individu tersebut mungkin kurang memiliki kebugaran kardiovaskular untuk menyelam dengan aman.

Beberapa individu, bagaimanapun, bergantung pada alat pacu jantung bukan karena otot jantung telah rusak tetapi hanya karena area yang menghasilkan impuls yang membuat otot jantung berkontraksi tidak berfungsi secara konsisten atau memadai. Atau sirkuit yang menghantarkan impuls ke otot jantung mungkin rusak, menghasilkan sinyal yang tidak tepat atau tidak teratur. Tanpa bantuan alat pacu jantung, individu tersebut mungkin menderita episode sinkop (pingsan). Orang lain mungkin menderita serangan jantung yang cukup ringan sehingga mereka mengalami kerusakan sisa minimal pada otot jantung mereka, tetapi sistem konduksi mereka tetap tidak dapat diandalkan dan karenanya membutuhkan dorongan dari alat pacu jantung.

If a cardiologist determines that an individual’s level of cardiovascular fitness is sufficient for safe diving, and the individual’s pacemaker is rated to function at a pressure of at least 130 feet (40 meters), that individual may be considered fit for recreational diving. But once again, it cannot be emphasized strongly enough that any divers with cardiac issues check with their doctor before diving.

Berikutnya Chapter 6 – Pulmonary and Venous Disorders >

“The risk of a DVT occurring on a flight lasting more than four hours is between 1 in 4,650 flights and 1 in 6,000 flights.”

Your lungs have many functions in your body beyond just oxygenating your blood. One of their other important roles is filtering the venous blood that returns from the body. The venous system is characterized by slower blood flow than the arterial system, which contributes to the occasional formation of a blood clot (known as a “peripheral venous thrombosis”), which could be transported into the lungs and could even cause a pulmonary embolism (or blockage in the vessels of the lungs).

In this chapter, you’ll learn about:

• Deep Vein Thrombosis
• Emboli Paru
• Immersion Pulmonary Edema

Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a condition in which a blood clot (a “thrombus”) forms in one or more of the body’s deep veins, usually in the legs. If a clot breaks free and travels through the circulatory system, it can lead to life-threatening conditions. For example, if a clot lodges in the lungs, it is known as a pulmonary embolism (PE) and affects the lungs’ ability to oxygenate the blood (see “Pulmonary Embolism”). Collectively, DVT and PE are sometimes referred to as venous thromboembolisms (VTEs).

A clot that originates as a DVT can also cause a stroke in individuals with a patent foramen ovale (PFO, a hole in the wall between the atria — see “Patent Foramen Ovale” for details about this condition); in such a case, the clot travels through the veins to the right atrium of the heart, passes through the PFO to the left atrium and then travels through the arteries to the brain.

DVT tidak terkait dengan menyelam, tetapi penyelam sering bepergian, dan perjalanan merupakan faktor risiko yang signifikan untuk DVT. Pada sekitar setengah dari semua kasus DVT, individu tidak mengalami gejala yang nyata sebelum timbulnya kondisi tersebut. Paling sering, itu dimulai di betis. Gejala mungkin termasuk yang berikut:

• Pembengkakan di kaki, pergelangan kaki atau kaki yang terkena
• Nyeri di betis yang menyebar ke pergelangan kaki atau kaki
• Kehangatan di daerah yang terkena
• A change in the color of the skin — to pale, red or blue

Sebagian besar VTE yang terkait dengan perjalanan udara terjadi dalam waktu dua minggu setelah penerbangan dan diselesaikan dalam waktu delapan minggu. Jika tidak diobati, DVT yang dimulai di betis akan menyebar ke paha dan panggul pada sekitar 25 persen kasus. DVT paha dan panggul yang tidak diobati memiliki risiko sekitar 50 persen mengarah ke PE, yang merupakan komplikasi DVT yang paling serius. Banyak kasus DVT tidak menunjukkan gejala dan sembuh secara spontan. Namun, DVT sering kambuh pada individu yang pernah mengalami satu episode kondisi tersebut.

Most DVTs occur in individuals with pre-existing risk factors for DVT who remain motionless for a long time — such as when traveling a long distance by plane, car or train; when doing deskwork over a period of many hours; or when bedridden. This is because immobility slows down the blood flow in the veins (a condition known as “venous stasis”); in addition, pressure on the calf from an inadequate seat can injure the vein walls. If you sit still for 90 minutes, the blood flow in your calf drops by half, and that doubles your chance of developing a blood clot. For every additional hour you spend sitting, your risk of a blood clot increases by 10 percent.

The incidence of DVT in the general population is one-tenth of one percent, but it is higher in those who have risk factors and those who travel often. Long-distance air travel may double or even quadruple the risk of suffering a VTE. Although DVT is often called the “economy class disease,” business-class travelers are susceptible, too. The risk of a DVT occurring on a flight lasting more than four hours is between 1 in 4,650 flights and 1 in 6,000 flights; this is lower than the risk in the general population, but that’s because people who take long trips are likely to be healthier than average. The incidence of DVT among travelers with a low to intermediate pre-existing risk for VTE who take a journey longer than eight hours was found to be 0.3 percent for symptomatic cases and 0.5 percent when including asymptomatic cases as well.

Faktor risiko DVT meliputi:

• Usia yang lebih tua (risiko meningkat setelah usia 40 tahun)
• Obesitas (didefinisikan sebagai indeks massa tubuh lebih besar dari 30)
• Penggunaan estrogen (baik kontrasepsi hormonal atau terapi penggantian hormon)
• Kehamilan (termasuk masa nifas)
• Trombofilia (kecenderungan peningkatan abnormal darah untuk menggumpal)
• VTE sebelumnya atau riwayat keluarga VTE
• Kanker aktif
• Gangguan medis yang serius
• Baru menjalani operasi, rawat inap atau trauma
• Mobilitas terbatas
• Central venous catheterization (the presence of a catheter in one’s chest, for use in administering medication or nutrients and/or drawing blood samples)

Antara 75 persen dan 99 persen dari mereka yang mengembangkan VTE terkait perjalanan memiliki lebih dari satu faktor risiko ini.

Height is also a factor in one’s risk of developing a travel-related DVT. People who are either very short — less than 5 feet, 3 inches (1.6 meters) — or very tall — more than 6 feet, 3 inches (1.9 meters) — appear to be at increased risk as a result of their inability to adjust their seats sufficiently to accommodate their height. In addition to effects of immobility, shorter passengers may suffer greater than usual seat-edge pressure on the backs of their knees, and taller passengers may be cramped due to insufficient leg room. All of these factors can contribute to injury of deep veins, venous stasis and activation of the blood’s clotting mechanisms.

Those who are at increased risk of DVT should wear compression socks whenever they fly or drive long distances and should consult their primary-care provider regarding the possible benefit of taking a clot-preventative such as aspirin. Although the risk of DVT for healthy people is small, everybody should be aware of the factors that can precipitate the condition — and avoid long periods of immobility. The best way to prevent DVT is to get up and walk around from time to time. It also helps to flex your feet and calf muscles regularly if you must remain seated for any length of time. Finally, it is also helpful in preventing DVT to stay well hydrated.

Efek pada Menyelam

Setiap individu yang telah didiagnosis dengan DVT akut atau yang menggunakan antikoagulan harus menahan diri dari menyelam. Dimungkinkan untuk kembali ke penyelaman yang aman setelah DVT, tetapi evaluasi kebugaran untuk menyelam harus dilakukan secara individual.

Emboli Paru

A pulmonary embolism (PE) is an obstruction (or “embolus”) that lodges in the vasculature of the pulmonary system, or lungs. The embolus may be air, fat or a blood clot (or “thrombus”). If a PE is caused by a thrombus, the clot typically originated in the deep vein system of the legs — a condition known as deep vein thrombosis (DVT); see “Deep Vein Thrombosis” for a discussion of DVT. The resulting obstruction in the flow of blood to the lungs typically causes a drop in cardiac output and a significant drop in blood pressure.

Onset PE bisa akut atau kronis. PE akut sering menyebabkan gejala yang jelas bagi individu, sementara PE dengan onset kronis sering mengungkapkan kehadirannya hanya dengan temuan yang sangat halus yang tidak diperhatikan oleh individu yang terkena. PE yang tidak diobati memiliki angka kematian yang tinggi. Prognosis yang sangat suram berlaku untuk individu yang memiliki DVT bersamaan, trombus ventrikel kanan atau disfungsi ventrikel kanan. Diperkirakan 1,5 persen dari semua kematian didiagnosis karena PE.

Risk factors for DVT — and thus for PE — include recent surgery; a stroke; a diagnosis of autoimmune disease, malignancy or heart disease; obesity; smoking; hypertension; and a previous DVT.

Symptoms of PE include chest pain (also known as “dyspnea”), pain or swelling of the calf (signaling a DVT), hypotension (abnormally low blood pressure), an altered level of consciousness and syncope (fainting). Distension of the neck veins in the absence of other conditions — such as pneumothorax (a buildup of air in the membrane surrounding the lungs, sometimes referred to as a collapsed lung) or heart failure — may also be observed in individuals suffering a PE.

PE should be one of the first conditions considered when attempting to make a diagnosis in someone exhibiting acute onset of any of the symptoms listed above and any of the associated risk factors. Appropriate diagnostic tests may include measurement of the individual’s levels of a hormone called brain natriuretic peptide (BNP) and of a protein known as cardiac troponin, as well as a CT angiogram of the lungs.

Treatment should focus initially on managing the significant cardiopulmonary impairments that are usually involved in a PE. Such care may include breathing support from an artificial ventilator and fluid management. The use of anticoagulant medication is also important, both to treat the embolus and to stop the development of another thrombus. Thrombolysis (known as “clot-busting”), embolectomy (surgical removal of the embolus) or the placement in the vena cava (one of the large vessels in the chest) of a filter designed to prevent any future clots from reaching the lungs may also be considered — especially in anyone who goes into shock, because mortality in such cases approaches 50 percent. Similar measures may be called for in cases of PE caused by a venous gas bubble. Hyperbaric oxygen therapy may be indicated as well, if the individual’s condition does not improve or deteriorates even after the application of supportive measures.

Efek pada Menyelam

Despite many medical advances, five-year all-cause mortality in individuals who have suffered a PE due to underlying risk factors remains more than 30 percent. And pulmonary hypertension — elevated pressure in the arteries that carry blood from the heart to the lungs, a condition that limits one’s exercise capacity — often persists in individuals who have had a PE, even after successful treatment. Thus any determination of fitness for diving by those who have had a PE must include an evaluation of their lung function, underlying conditions, anticoagulation status, exercise capacity and cardiac status.

Immersion Pulmonary Edema

Immersion pulmonary edema (IPE) is a form of pulmonary edema — an accumulation of fluid in the tissues of the lungs — that specifically affects divers and swimmers. Immersion at depth is a key factor in the development of IPE. That’s because immersion in an upright position causes a significant shift of fluid from the peripheral to the central circulatory system, resulting in higher pressure in the capillaries of the pulmonary system. Elements of the diving milieu that contribute to IPE’s occurrence include the fact that divers breathe gases that are denser than air at sea level, which means more negative pressure within chest is needed to inhale; the likelihood of gas bubbles becoming trapped in the vasculature of the lungs; the cold underwater environment; and the potential in underwater settings for exertion or panic, which can exacerbate elevated capillary pressure.

Maintaining a proper fluid balance in your lung tissue and its vasculature requires a dynamic combination of various opposing forces. Unopposed changes in any of these forces can result in a buildup of excess fluid — or edema — in your pulmonary tissue. The main variables involved in regulating this fluid balance are the following:

• Tekanan onkotik (suatu bentuk tekanan yang diberikan oleh protein) di kapiler paru, pembuluh terkecil dari sistem peredaran darah
• Oncotic pressure in the pulmonary system’s interstitial fluid (fluid in the cavities of your lung tissue)
• Permeabilitas kapiler paru
• Tekanan hidrostatik (tekanan cairan saat istirahat) di kapiler paru
• Tekanan hidrolik (tekanan cairan yang dikompresi atau dipompa) dalam cairan interstitial
• Tekanan di alveolus, kantung udara kecil di paru-paru.

These factors, which collectively are known as “Starling forces,” can all be quantified and placed in an equation that can then be used to calculate the net differential of
yang bekerja.

Pulmonary edema is caused by changes in these forces — such as a drop in the levels of key proteins in the blood; leakage from the pulmonary capillaries due to sepsis (a life-threatening complication of infections); an increase in hydrostatic pressure in the pulmonary capillaries due to heart failure; and negative pressure in the alveoli due to resistance from breathing through a faulty regulator. Additional issues that can contribute to the development of pulmonary edema include side effects of some cardiovascular drugs; ARDS (acute respiratory distress syndrome, a life-threatening condition that prevents oxygen from getting to the lungs); reperfusion (a procedure that restores circulation after a heart attack or stroke); cardiomyopathy (a weakening of the heart muscle); high-altitude pulmonary edema; a pulmonary embolus (a blood clot lodged in a vessel in the lungs); re-expansion (the reinflation of a collapsed lung); pulmonary hypertension (elevated pressure in the arteries that carry blood from the heart to the lungs); lung cancer; hemorrhage (uncontrolled bleeding); and various disorders of the nervous system. Other factors can include overhydration by well-intentioned divers who have heard the conventional wisdom that dehydration is a risk factor for decompression sickness, as well as poor physical conditioning, which can result in increased negative pressure in the alveoli during deep inspiration.

Gejala IPE termasuk nyeri dada; dispnea (ketidaknyamanan atau kesulitan bernapas); mengi; dan dahak berwarna merah muda dan berbusa saat terendam atau segera setelah keluar dari air. Kebanyakan orang yang menderita episode IPE tidak memiliki riwayat atau tanda signifikan yang menunjukkan kerentanan terhadap kondisi tersebut; namun, risiko IPE memang meningkat seiring bertambahnya usia, obesitas, dan tekanan darah tinggi.

Once pulmonary edema occurs, hypoxia (lack of an adequate supply of oxygen) leads to constriction of the pulmonary vasculature, which worsens the cascade of ill effects. The situation can be further aggravated by the accompanying dyspnea, which, when experienced underwater, can induce panic and uncontrolled ascent to the surface — leading to overinflation of the lungs and even near-drowning.

To help differentiate immersion pulmonary edema from other conditions with similar symptoms (such as near-drowning, pulmonary decompression sickness and pulmonary overinflation syndrome), it is important to keep in mind that IPE’s onset can occur either at depth or upon reaching the surface. And it is not necessarily precipitated by aggressive diving, a rapid ascent or the aspiration of water.

Treatment for IPE should begin with removal of the affected individual from the water (to relieve the compression of the vessels in the lower extremities, allowing centrally pooled fluids to return to the extremities) and with administration of oxygen (beginning at 100 percent and later at a reduced concentration). A diuretic such as Lasix may help to reduce excess intravascular fluid, although diuresis — the body’s natural excretion of fluid — may already be under way as a result of hormonal influences. The condition usually resolves quickly in a healthy diver. Prolonged hospitalization is rarely required; if it is necessary, it’s usually due to contributing factors, such as an underlying cardiac problem.

Efek pada Menyelam

Some divers have one episode of IPE and never experience the condition again, but repeated episodes are likely. Any individuals who suffer a first episode of IPE are advised to undergo a detailed examination to rule out any medical conditions that may have caused the edema and then to have a thorough discussion with their physician regarding the risks of continuing to dive. And all divers are urged to have regular maintenance on their regulators, to refrain from overhydration and to attend to proper dive planning in order to avoid exertion and panic — as well as to keep conditions such as obesity and hypertension under control.

Berikutnya Chapter 7 – Issues Involving Cardiovascular Drugs >

“Divers who take drugs to treat cardiovascular diseases often worry about the drugs’ compatibility with diving. However, in most cases, it is the underlying condition and not the drug that should cause concern.”

Some drugs may have side effects that preclude diving. Divers should be very familiar with the side effects of any drugs they take and should discuss them with their physician — and be sure their physician knows about their diving activities. A one-time clearance to dive does not preclude progression of a disease, so any changes in your health status should prompt another medical examination before you dive again.

In this chapter, you’ll learn about:

• Antiplatelet dan Antikoagulan
• Statins
• Antihipertensi
• Antiaritmia

Antiplatelet dan Antikoagulan

Antiplatelets and anticoagulants are two classes of drugs — popularly known as “blood thinners” — that reduce the risk of clot formation and thus the risk of deep vein thrombosis, pulmonary embolism, heart attack and stroke. They may also be prescribed for individuals who have been diagnosed with atrial fibrillation or for those who have had heart-valve surgery or who have received a stent, an implanted pacemaker or an implanted defibrillator. (See other sections for detailed descriptions of these conditions.)

Gumpalan terbentuk ketika sel-sel darah yang dikenal sebagai trombosit saling menempel, dan kemudian protein dalam darah mengikatnya menjadi massa padat. Pembekuan adalah fungsi normal yang membatasi dan menghentikan pendarahan ketika pembuluh darah terluka. Namun, jika gumpalan tumbuh di luar kendali atau mulai bergerak di dalam sistem peredaran darah, maka itu menimbulkan bahaya. Gumpalan mungkin tersangkut di arteri pulmonalis dan menyebabkan emboli paru; di arteri jantung dan menyebabkan serangan jantung; atau di pembuluh otak dan menyebabkan stroke. Semua peristiwa ini dapat mengancam jiwa.

Antiplatelet dan antikoagulan menjaga darah dari pembekuan secepat atau seefektif biasanya dengan mencegah trombosit menempel satu sama lain dan dengan mencegah protein pembekuan mengikat bersama. Mereka bahkan dapat membantu memecah gumpalan yang sudah terbentuk.

Antiplatelets — such as aspirin and clopidogrel (also known by the brand name Plavix) — work by preventing the platelets from adhering to one another.

Anticoagulants — such as heparin and warfarin (Coumadin) — inhibit the action of the clotting proteins and thus slow down the chemical reactions that lead to the formation of a clot. There were also several new anticoagulants approved between 2010 and 2012, including rivaroxaban (Xarelto), dabigatran (Pradaxa) and apixaban (Eliquis).

The major side effect of all antiplatelets and anticoagulants is excessive bleeding. Those taking such drugs — especially at too high a dosage — may bleed or bruise easily or may experience bleeding that does not stop as quickly as usual.

Perhatian Khusus Mengenai Warfarin

Individuals who take warfarin (Coumadin) are generally advised to avoid any activities that may cause abrasions, bruising or cuts — such as contact sports. They are also urged to exercise caution while brushing their teeth and shaving. Even such trivial injuries as insect bites may cause complications in anyone taking warfarin.

There are additional risks involving warfarin particular to diving. Most significantly, there is an appreciable chance of serious injury in any diving environment, despite one’s best efforts to mitigate the risk. Cuts and bruises are unavoidable, for example. And in anyone taking warfarin, a decompression injury or difficulty equalizing ear pressure could cause bleeding in the ears or the spinal cord that would otherwise not occur.

Selain itu, baik perjalanan maupun gangguan pola makan yang diakibatkannya dapat mengganggu kerja warfarin dengan cara yang berbahaya. Selain itu, kemampuan perawatan kesehatan di banyak tujuan penyelaman populer mungkin tidak cukup untuk memberikan perawatan yang diperlukan jika terjadi peristiwa yang kurang menguntungkan.

Untuk semua alasan ini, siapa pun yang menggunakan warfarin umumnya disarankan untuk tidak menyelam. Namun demikian, banyak orang yang menggunakan warfarin dapat menyelam tanpa komplikasi besar. Kunci menyelam yang aman saat menggunakan warfarin adalah kepatuhan yang ketat terhadap tes darah bulanan dan pengawasan rutin oleh dokter. Dengan kontrol pengenceran darah yang baik, risiko komplikasi perdarahan cukup rendah.

According to Dr. Alfred Bove, a dive-medicine specialist, “For divers, the most important question is whether the condition that requires the use of Coumadin or Plavix prohibits diving. In many cases, the illness is over, or chronic but well adjusted, and does not interfere with safe recreational diving. Safe diving with Coumadin or Plavix depends on the absence of illness that would limit diving, careful control of clotting time, avoiding ear or sinus squeeze, and a thorough education on drugs and foods which cause changes in the effects of Coumadin. There are many divers using Coumadin and Plavix safely, but a special effort must be made to understand how to avoid problems of excess or not enough anticoagulation.”

Statins

Statins are a class of drugs prescribed to lower high blood cholesterol and thus prevent heart attack and stroke. They reduce both LDL cholesterol (“bad cholesterol”) and inflammation in the arteries. Statins work by inhibiting a liver enzyme that is involved in the production of cholesterol. Though they are most effective at lowering LDL cholesterol, they may also contribute to raising HDL cholesterol (“good cholesterol”).

Common statins include the following — listed first by their generic name and, in parentheses, their brand name:

• Atorvastatin (Lipitor)
• Cholestipol (Cholestid)
• Colesevalam hydrochloride (Welchol)
• Fluvastatin (Lescol)
• Lovastatin (Mevacor)
• Ezetimibe (Zetia)
• Ezetimibe combined with simvastatin (Vytorin)
• Fenofibrate (Tricor)
• Pravastatin (Pravachol)
• Rosuvastatin (Crestor)
• Simvastatin (Zocor)

Uji klinis yang disponsori oleh perusahaan yang memproduksi obat ini telah menemukan efek samping yang jarang dan ringan. Namun, dalam uji coba yang dirancang dengan cermat yang dikenal sebagai IDEAL, hampir 90 persen subjek melaporkan efek samping, hampir setengahnya serius. Efek samping statin yang telah dicatat dalam literatur medis dan yang dapat mengganggu penyelaman meliputi:

• Dispnea (ketidaknyamanan atau kesulitan bernapas)
• Nyeri otot
• Komplikasi tendon
• Masalah pencernaan
• Ruam atau kulit memerah
• Peningkatan gula darah atau diabetes tipe 2.
• Disfungsi kognitif (Beberapa penelitian melaporkan bahwa hingga 75 persen dari mereka yang menggunakan statin mengalami disfungsi kognitif yang ditentukan mungkin atau pasti terkait dengan terapi statin; keparahan defisit kognitif jelas terkait dengan potensi statin.)
• Kelelahan (Hampir setengah dari mereka dalam studi 2012 melaporkan peningkatan kelelahan yang signifikan saat menggunakan statin.)

Efek samping statin yang paling umum adalah nyeri otot. Ini terjadi pada sekitar 20 persen dari mereka yang memakai statin. Rasa sakit ini mungkin terasa seperti pegal-pegal, pegal-pegal, kelelahan atau kelemahan pada otot-otot Anda. Rasa sakit kadang-kadang digambarkan sebagai ketidaknyamanan ringan, tetapi kadang-kadang cukup parah untuk membuat aktivitas sehari-hari menjadi sulit. Para ilmuwan menduga terjadinya rasa sakit adalah karena fakta bahwa statin memblokir produksi molekul yang digunakan tubuh untuk menghasilkan energi, yang disebut CoQ10; uji klinis saat ini sedang menjajaki apakah mengonsumsi suplemen CoQ10 dapat mencegah efek samping ini. Namun, penggunaan suplemen CoQ10 secara rutin tidak dianjurkan, meskipun ada beberapa masalah keamanan dengan suplemen tersebut.

Sangat jarang, statin dapat menyebabkan semacam kerusakan otot yang mengancam jiwa yang disebut rhabdomyolysis; itu menyebabkan nyeri otot yang parah dan dapat mengakibatkan kerusakan hati, gagal ginjal dan kematian. Rhabdomyolysis sangat mungkin terjadi pada mereka yang menggunakan statin dalam kombinasi dengan obat lain seperti antibiotik dan antidepresan atau pada mereka yang menggunakan statin dosis tinggi.

Beberapa orang yang menggunakan statin dapat mengalami mual, gas, diare atau sembelit. Efek samping ini jarang terjadi.

Ruam atau kemerahan juga dapat terjadi setelah mengonsumsi statin. Ini lebih mungkin terjadi pada individu yang menggunakan statin dan niasin bersama-sama, baik dalam pil kombinasi seperti Simcor atau sebagai dua obat terpisah.

The FDA warns on statin labels that some people taking statins have developed memory loss or confusion; these effects are reversed when the medication is halted. Conversely, there has also been evidence that statins may help with brain function — in patients with dementia or Alzheimer’s, for example. This effect is still being studied.

Tetapi tidak peduli apa efek samping yang mungkin dialami individu yang menggunakan statin, penting agar mereka tidak berhenti minum obat tanpa berbicara dengan dokter mereka. Penting juga bagi mereka yang menggunakan statin untuk meminimalkan perubahan gaya hidup, pola makan, dan obat-obatan yang dijual bebas, terutama selama perjalanan yang berhubungan dengan menyelam.

Faktor risiko untuk efek samping statin meliputi:

• Memakai beberapa obat penurun kolesterol
• Berusia 65 tahun atau lebih, perempuan atau memiliki kerangka tubuh yang lebih kecil
• Memiliki penyakit ginjal atau hati atau diabetes tipe 1 atau 2.
• Minum terlalu banyak alkohol (lebih dari dua gelas sehari untuk pria berusia 65 tahun ke bawah atau lebih dari satu gelas sehari untuk wanita dari segala usia dan pria di atas 65 tahun)

Selain itu, masalah lebih mungkin terjadi pada mereka yang menggunakan statin dan obat-obatan berikut:

• Antimalaria, seperti klorokuin dan hidroksiklorokuin (Plaquenil)
• Pengobatan tiroid

Efek pada Menyelam

Meskipun efek samping dari beberapa statin dapat mengganggu penyelaman, mereka mungkin menawarkan manfaat kesehatan secara keseluruhan.

One of the effects of statins is an increase in the body’s production of nitric oxide. This helps to preserve the integrity of the endothelium (the inner lining of the blood vessels), to reduce injury from ischemia and/or reperfusion (a procedure that restores circulation after a heart attack or stroke) and to depress interdependent inflammatory and coagulation activity — all of which could provide protection against decompression sickness (DCS). On the other hand, a study of healthy divers who took either a statin or a placebo several days before a dive found no difference in their risk of postdive venous gas bubbles. Thus taking statins specifically to prevent DCS does not appear to offer any benefit, especially in view of the possibility of adverse side effects.

If you are over age 45 and are already taking statins for medical reasons, you need to answer “yes” to at least two questions on the Recreational Scuba Training Council (RSTC) Medical Statement (see the “Physical Activity Recommendations” section for details regarding this form):

T: Apakah saat ini Anda sedang mengonsumsi obat resep? (kecuali alat kontrasepsi atau antimalaria)?

T: Apakah Anda berusia di atas 45 tahun dan dapat menjawab YA untuk satu atau lebih jawaban berikut?

• Memiliki kadar kolesterol tinggi

Kedua respons positif ini menandakan kondisi yang sudah ada sebelumnya yang dapat memengaruhi keselamatan Anda saat menyelam dan yang memerlukan pemeriksaan medis menyeluruh untuk memeriksa adanya faktor risiko lain atau tanda penyakit kardiovaskular. Memang, siapa pun yang berusia di atas 45 tahun, yang berisiko tinggi mengalami masalah jantung atau yang memiliki tanda-tanda penyakit kardiovaskular harus mengunjungi dokter setidaknya sekali setiap tahun.

Perhatikan juga bahwa izin menyelam satu kali tidak menghalangi perkembangan penyakit, jadi setiap perubahan status kesehatan Anda harus meminta pemeriksaan medis lain sebelum Anda menyelam lagi. Penyelam juga harus memperhatikan fakta bahwa mereka mungkin diminta untuk mengisi Pernyataan Medis RSTC baru sebelum penyelaman apa pun dan bahwa mereka dapat ditolak izinnya untuk menyelam berdasarkan tanggapan mereka. Namun, sebagian besar operator selam akan menerima bukti izin medis terbaru untuk menyelam. Jika Anda ragu tentang kebugaran Anda untuk menyelam, diskusikan status Anda dengan operator selam Anda terlebih dahulu.

Antihipertensi

Ada sejumlah obat yang dapat digunakan untuk menurunkan hipertensi (yang juga disebut sebagai tekanan darah tinggi). Efek sampingnya bervariasi, sehingga beberapa lebih cocok daripada yang lain untuk digunakan oleh penyelam.

Penghambat Beta (Beta Blockers)

Beta blockers are commonly prescribed to treat hypertension, but they have a big drawback for divers: They can reduce the heart’s capacity for exercise. If a medication restricts the heart’s function during exercise, then there is an increased risk of loss of consciousness, which could prove fatal while diving.

Because of this effect, doctors often recommend that those who take beta blockers undergo a stress test before diving. According to Dr. Alfred Bove, a dive-medicine specialist, divers who take beta blockers but who can achieve a strenuous level of exercise without severe fatigue can be cleared for diving. Bove also points out that although diving does not usually represent the maximum workload on an individual’s heart, anyone who takes beta blockers should avoid extreme exercise because their maximum exercise capacity may be reduced.

ACE Inhibitors

Drugs known as ACE (angiotension-converting enzyme) inhibitors have less effect on exercise capacity than beta blockers, so many doctors prescribe them for people who exercise frequently. But although ACE inhibitors seem to have fewer adverse effects, they can lead to a cough or to airway swelling — conditions that could cause severe problems underwater. If a cough related to ACE-inhibitor use persists, many physicians will recommend a different medication. ACE inhibitors should also be avoided by anyone with kidney disease.

Calcium Channel Blockers

Calcium channel blockers don’t typically pose problems for divers; they relax the walls of the blood vessels, reducing resistance to the flow of blood and thus lowering blood pressure. However, some individuals who take calcium channel blockers, especially in moderate doses, find that a change of position from sitting or lying down to standing causes a drop in blood pressure and thus momentary dizziness. This effect may be cause for concern in divers, but calcium channel blockers appear to have no other adverse implications for diving.

Diuretik

Diuretics reduce the amount of excess water and salt in the body; the decline in the volume of bodily fluids results in a lowering of the blood pressure. Divers seem to have very little trouble with diuretics, although in very warm environments, they may cause excessive water loss and thus dehydration. Because dehydration seems to contribute to the risk of decompression sickness, divers may want to reduce their diuretic dosage on days that they engage in diving — though they should check with their doctor before doing so.

Antiaritmia

Antiaritmia dirancang untuk membantu jantung Anda mempertahankan ritme yang stabil. Alfred Bove, seorang spesialis pengobatan selam, memperingatkan bahwa beberapa antiaritmia, bila dikombinasikan dengan olahraga dan menurunkan kadar potasium, dapat meningkatkan risiko cedera pada jantung. Meskipun obat-obatan tersebut biasanya tidak mengganggu penyelaman, aritmia yang menyebabkan obat tersebut dikonsumsi sendiri dapat menghalangi penyelaman yang aman. Konsultasi menyeluruh dengan ahli jantung dan spesialis kedokteran selam sangat penting jika Anda minum obat untuk mengontrol detak jantung yang tidak normal dan ingin mempertimbangkan untuk menyelam.

Berikutnya Bacaan dan Sumber Lebih Lanjut >

Cedera telinga adalah penyebab utama cedera di antara penyelam scuba. Banyak dari cedera ini dapat dengan mudah dicegah. Buku referensi Telinga & Menyelam mengkaji anatomi telinga yang kompleks, teknik penyamaan tekanan yang tepat, gejala cedera, kondisi medis dan pentingnya kebersihan telinga yang baik dalam perawatan pencegahan dan pengelolaan organ vital ini.

In this book, you’ll learn about:

• Chapter 1 – Key Information
  • Anatomi Telinga
  • Ekualisasi Telinga Bagian Tengah
• Chapter 2 – Injuries
  • Barotrauma Telinga Bagian Tengah
  • Gendang Telinga Berlubang
  • Barotrauma Telinga Bagian Dalam
  • Perilymph Fistula
  • Vertigo Alternobarik
  • Tekanan Terbalik (Reverse Squeeze)
  • Baroparesis Wajah
  • TMJ
  • Surfer’s Ear
  • Swimmer’s Ear
• Chapter 3 – Symptoms
  • Mabuk Laut atau Mabuk Perjalanan
  • Vertigo
  • Tinitus (Telinga Berdenging)
  • Gangguan Pendengaran/Ketulian
• Chapter 4 – Hygiene
  • Kebersihan Aural
  • Sumbat Telinga
  • Tetes Telinga
  • Tabung Ventilasi Telinga
• Chapter 5 – Medical Conditions
  • Meniere’s Disease
  • Septum Menyimpang (Deviated Septum)

Kredit:

Petar Denoble, MD, DSc – Managing Editor
James Chimiak, MD – Editor