Decompression Sickness

(Caisson (Caisson) disease; local joint or muscle pain, so-called Bends.)

The decompression sickness occurs when the rapid decrease of the external pressure caused (eg., During the emergence of the depth of the exit from a caisson or a hyperbaric chamber or a rise in the level), that gas previously dissolved in blood or tissue was, forms bubbles in the blood vessels. Among the characteristic symptoms include pain, neurologic symptoms, or both. Severe cases can lead to death. The diagnosis is made clinically. The best treatment is the hyperbaric oxygen therapy. Proper diving techniques are essential for prevention.

The Henry’s Law states that the solubility of a gas is directly proportional to the pressure exerted on the gas and the liquid pressure in a liquid. Therefore, the amount of inert gas (eg. N2 example, helium), which is incorporated in the blood and tissues at higher pressure to.

The decompression sickness occurs when the rapid decrease of the external pressure caused (eg., During the emergence of the depth of the exit from a caisson or a hyperbaric chamber or a rise in the level), that gas previously dissolved in blood or tissue was, forms bubbles in the blood vessels. Among the characteristic symptoms include pain, neurologic symptoms, or both. Severe cases can lead to death. The diagnosis is made clinically. The best treatment is the hyperbaric oxygen therapy. Proper diving techniques are essential for prevention. The Henry’s Law states that the solubility of a gas is directly proportional to the pressure exerted on the gas and the liquid pressure in a liquid. Therefore, the amount of inert gas (eg. N2 example, helium), which is incorporated in the blood and tissues at higher pressure to. During the emergence of the depth when the diver wears the surrounding pressure, bubbles can form (mainly N2). The released gas bubbles can occur in any tissue and cause local symptoms or they can migrate through the blood to distant organs (arterial Gasemboloie). The bubbles cause symptoms by sealing the vessels tearing tissue or compress, or activate coagulation and inflammation cascade. Because N2 readily dissolves in fat tissues with high lipid content (eg. As CNS) are particularly vulnerable. Risk factors for decompression sickness Decompression sickness occurs among scuba divers at about 2-4 in 10,000 dives. The incidence is higher among professional divers who often have minor musculoskeletal injuries. Risk factors include dives in cold temperatures dehydration sporting activity after diving Fatigue flying after diving Obesity Advanced age Extensive or deep dives rapid ascent Cardiac right-left shunts Since the excess N2 remains dissolved in the body tissue at least 12 hours after each dipping operation, multiple dives are connected within a day with a higher probability of decompression sickness. The decompression may also occur when the pressure decreases below atmospheric pressure (eg. As by the action of height). Classification of decompression sickness There are generally two forms of decompression sickness: Type I affects joints, skin and lymphatic system, is easier and usually not life threatening. Type II is severe, sometimes life-threatening, and relates to various organ systems. The spinal cord is especially vulnerable; the other vulnerable organ systems are central nervous system, the respiratory system (eg. B. pulmonary embolism) and the circulatory system (eg. as heart failure, cardiogenic shock). “Bends” refer to local joint or muscle pain resulting from decompression sickness, but are often used as a synonym for each component of the disease. Symptoms and signs Severe symptoms can appear within a few minutes after surfacing to the surface, but the symptoms in most patients begin gradually, sometimes with early symptoms such as malaise, fatigue, anorexia and headache. Symptoms occur in about 50% of patients within one hour and at 90% within 6 hours after surfacing to the surface. In rare cases, the symptoms may manifest after 24-48 hours after surfacing to the surface, v. a. after an exposure level after the dive (z. B. when flying). Decompression sickness type Iverursacht typically increasingly worsening pain in the joints (usually in the elbows and shoulders) in the back and in the muscles; upon movement of the pain is amplified and is described as “dull” and “boring”. Other symptoms include swollen lymph nodes, Hautmarmorierung, itching and rash. Decompression sickness type II can sometimes cause neurological and respiratory symptoms. They usually manifested by paralysis, numbness and “pins and needles”, difficulty in urination and loss of bowel and bladder continence. Headache and fatigue may be associated symptoms, but are not specific. Dizziness, tinnitus and hearing loss can arise if the inner ear is affected. Among the serious symptoms include seizures, slurred speech, vision loss, confusion and coma; death can occur. Suffocation (respiratory decompression sickness) are rare but serious signs; Symptoms include shortness of breath to, chest pain and coughing. A massive embolization of pulmonary flow path by gas bubbles rapidly cardiovascular failure and death can follow. The dysbare osteonecrosis is a late manifestation of decompression sickness. It is an insidious form of aseptic osteonecrosis caused by long or short succession following repeated exposure to pressurized parts of the body (typically more likely in people who work in compressed air and in professional, working at great depths divers at recreational divers). The destruction of the articular surfaces of shoulders and hips can cause chronic pain and severe disabilities. Diagnosis Clinical evaluation Diagnosis is clinical. CT and MRI can be useful to rule out other diseases that verusachen like symptoms, such. B. herniated disc, ischemic stroke or cerebral hemorrhage. Although these methods may present abnormalities in the brain or in the spinal cord, they are not sensitive to the decompression sickness; treatment should usually start on the basis of clinical suspicion. An arterial gas embolism can sometimes have similar manifestations, see Table: Comparison of gas embolism using the decompression sickness). When dysbaren osteonecrosis radiographs may represent the degenerative changes of the joints that can not be distinguished from a degeneration from other joint diseases; by means of an MRI diagnosis can usually be provided. Tips and risks When decompression sickness is suspected, should be started immediately with a recompression without delays due to diagnostic tests. Treatment 100% O2 Hyperbaric oxygen therapy (HBO) Approximately 80% of patients recover completely. Initially, 100% O2 improves high flow N2 washout by increasing the N2 pressure gradient between the lungs and circulatory system; this speeds up the absorption of embolic gas bubbles. For all patients, with the possible exception of those whose symptoms are limited to itching, Hautmarmorierung and fatigue, hyperbaric oxygen therapy is indicated; they should be monitored for worsening back. The other patients are transported to a suitable pressure chamber unit. Because the time to treatment and the severity of the injury are important determinants of the outcome, the transport should not be in favor of less important measures is delayed. If an air extraction is required, an aircraft that has 1 atmosphere pressure, is preferred. For airplanes with no pressure equalization a small height should be (<609 m [<2000 ft]) followed. Airliners have, even if they have pressure compensation, usually a cabin pressure equivalent to an altitude of 2438 m; this may worsen the symptoms. Flying in commercial aircraft shortly after diving may cause the symptoms. Prevention A relevant blistering can usually be avoided by limiting the depth and duration of the dive to an area where no Dekompressionszwischenstopps when emerging from the depths must be made (no-stop limits) or by the emergence from the depths with Dekompressionszwischenstopps according the published guidelines (such as the decompression table in Chapter diagnosis and treatment of Dekompressionsübelkeit in diving manual for the US Navy US Navy Diving manual;.. s www.diverlink.com/library/usn). Many divers now have a portable dive computer with you, indicating the depth and the dive time at depth and creates a decompression. In addition to the following published in various media guidelines make many divers at about 4.6 m below the surface for a few minutes a safety stop. Nevertheless, a few cases develop after correctly as "no-stop dives' deemed dives, and the incidence of decompression sickness has not decreased despite the widespread use of dive computers. The reason for this may be that the tables and computer programs published account of the differences in risk factors for divers not complete or that the diver does not follow the recommendations precisely. Dives, which are at a distance of <24 h apart require special techniques to determine the correct decompression. Summary of decompression sickness symptoms show up within one hour after the appearance in 50% of affected patients and in 6 hours at 90%. A severe decompression sickness with brain dysfunction within minutes after surfacing can be hard to distinguish from the arterial gas embolism. If the disease is suspected, with 100% O2 should be treated with high flow and as soon as possible a transfer to a pressure chamber or an airplane be carried out with an internal pressure of 1 atmosphere. Divers should follow the established recommendations (z. B. the depth and duration, to use decompression during ascent), which reduce the risk of decompression sickness. For more information Divers Alert Network: 24-hour emergency hotline, 919-684-9111 SEA 00C: Office of the Director of Ocean Engineering Supervisor and Diving

Health Life Media Team

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