Risk
Factors For Decompression Sickness
Elsye Fitriasari1, Ni Komang
Sri Dewi Untari2, Nasywa Annisa Fitra3
Naval Health Institute Surabaya
Email: [email protected]1, [email protected]2,
[email protected]3
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Abstract |
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Over the past few decades, self-contained
underwater breathing apparatus (SCUBA) diving has gained popularity globally.
Efforts to explore new trails underwater have rapidly expanded recreational,
technical, professional, and military diving opportunities. Decompression
sickness (DCS) is an essential and complex health problem among divers,
stemming from changes in environmental pressure during and after underwater
travel. Understanding the various risk factors associated with DCS is
critical in implementing safe diving practices. Medical professionals, regardless
of specialization, need to be aware of the adverse effects of changes in
exposure to environmental stresses on the human body. Decompression sickness
(DCS) can occur quickly, immediately, or very mildly and is delayed. Divers
with DCS can arrive late, far from the dive site, due to their varied
presentation, slow start, and air travel after diving. Medical personnel must
consider the previous days' activities and be aware of diving problems and
disorders to take advantage of the opportunity to diagnose and treat such
patients appropriately. Individual and environmental risk factors play a role
in increasing the incidence of DCS in divers, including obesity, smoking,
alcohol, anxiety disorders, comorbidities, previous injuries, cold water,
duration, and depth of diving. A comprehensive understanding of these
multifaceted risk elements is essential for divers and medical professionals.
Armed with this knowledge, they can better assess potential risks, adopt
proactive precautions, and ensure diver safety, ultimately reducing severe
DCS incidents. Keywords:
�Efforts to explore new underwater pathways
have rapidly expanded recreational, Technical, Professional, and Military
diving opportunities. |
The increase in
environmental pressure, the difference in breathing gases used for diving (with
different fractions of inert and saturated gases), the rules governing their
behavior, and the correct decompression procedure are considered widely known.
Generally, decompression tables or dive computers are used to control DCS risk
by using the concept of "master network" to calculate the depth and
stopping time of decompression (Cialoni et al., & Marroni, 2017). Nonetheless,
several other individual and environment-related risk factors have been
identified to increase the risk of DCS events. Individual factors include a
high body mass index (BMI), smoking, a previous history of DCS, and a patented
foramen ovale. At the same time, environmental factors are related to cold sea
water temperatures and heated diver suits. Some of these risk factors have been
elucidated mechanisms associated with increased risk of DCS. In contrast,
others are still being studied (Cooper & Hanson, 2019) (Savioli et al., 2022). This literature
review discusses decompression sickness, especially in divers, and describes
related risk factors according to the novelty of the literature.
A comprehensive
search of electronic databases was conducted to identify relevant studies
published between January 2009 and December 2023. The inclusion criteria are
(1) observational or experimental studies examining risk factors in
decompression sickness and (2) the study was published in a peer-reviewed
journal. Two reviewers independently screened the study titles and abstracts
identified in the search, and the full-text article was reviewed for
notability. Quality assessments of the included studies were conducted using
the Newcastle-Ottawa Scale. Data is extracted and synthesized using narrative
synthesis.
Definition and
Classification of Decompression Sickness
����������� Decompression sickness (Decompression
Sickness/DCS) occurs when a dissolved gas (usually nitrogen or helium, used
in diving or diving with a mixture of gases) escapes from solution and forms
bubbles in the body as pressure drops occur (Pollock & Buteau, 2017).
����������� Decompression sickness (Decompression
Sickness/DCS) can occur during underwater dives (at the time of elevation),
working in caissons, flying in unpressurized aircraft, and activities outside
the spacecraft. However, this literature review is devoted to DCS due to
diving, where appropriate decompression procedures can help reduce the risk of
DCS, which is different from other conditions where it may be challenging to
perform (Edge & Wilmshurst, 2021).
����������� Experts categorize DCS into Type I,
with symptoms involving the skin, musculoskeletal system, or lymphatic system
only, and Type II, with symptoms involving the central nervous system.
Decompression sickness (Decompression Sickness/DCSType I is
characterized by one or a combination of the following symptoms: (1) mild pain
that begins to disappear within 10 minutes after the onset of pain (niggles);
(2) pruritus, or "twisted skin/Skin Bends"(Figure 2.1.), which
causes itching or burning of the skin; and (3) Cutis marmorata (Figure
2.2.) (Mitchell et al., 2018).
Figure
2.1. Skin Bends on Divers
(Source:
Divers Alert Network)
����������� DCS type II has the following
characteristics: (1) pulmonary symptoms, (2) hypovolemic shock, or (3) nervous
system involvement. Pain only occurs in about 30% of cases. Due to the central
and peripheral nervous system's anatomical complexity, signs and symptoms vary.
Symptoms usually occur immediately but can occur up to 36 hours later.
Figure
2.2. Cutis Marmorata on DCS
(Source:
Kalentzos, 2010: 9)
Etiology
����������� Decompression sickness (Decompression
Sickness(DCS) is the formation, growth, and elimination of bubbles caused
by decreased environmental pressure that produces an inert gas, usually
nitrogen, that dissolves in solution within body tissues. Rapid changes in
breathing air pressure and increased amounts of oxygen and nitrogen in various
body tissues eventually lead to this condition. As stated by Henry's law (Henry's
law), at a constant temperature, the amount of gas dissolved is
proportional to its partial pressure above the liquid. Individuals who breathe
air in a pressurized environment reach a gas equilibrium/saturation state. This
dissolved gas will be removed from the solution when it leaves a high-pressure
environment to a lower-pressure environment, such as rising from depth during Self-contained
underwater breathing apparatus (SCUBA), leaving the job site caisson,
or climbing to altitude indoors without pressurization.
Epidemiology
����������� In the United States, between 1987
and 2003, the Sports & Fitness Industry Association (formerly the Sports
Equipment Manufacturers Association) estimated that the number of scuba divers
who dived at least once a year increased by 32.1% from 2.4 to 3.2 million
participants. However, during the 6 years 2000-2006, there was a decrease of
23% to 3.2 million. The peak year was in 1998 at 3.5 million. However, it is
estimated that only about one-third of divers were active or regular
participants. About two-thirds of divers are regular or novice divers. In 2015,
more than 23 million scuba diver certifications have been issued worldwide,
with an estimated 7 million active divers. Experience results in safer divers,
although, on the other hand, excessive self-confidence can lead to motivation
that exceeds the limits of ability (Glazer & Telian, 2016).
����������� As a result of variability in
reporting and information gathering, medical journal publications on
diving-related injury statistics need to be more consistent. In this case, to
improve the collection of statistical information, the Divers Alert Network
(DAN), based in North Carolina in the United States, acts as a medical
information and referral service for diving-related injuries. In addition to
these roles, the institution provides education, acts as an information
institution (clearinghouse) for diving-related injury reports from
around the world, and participates in research related to diving injuries and
illnesses. They also sponsor a long-term Project Dive Exploration (PDE)
research study. According to DAN, less than 1% of divers experience DCS (Lautridou et al., 2020).
����������� If proper decompression procedures
are followed, DCS is also rare. Incidence rates (per dive) in open water
operational dives of a duration of a few minutes to several hours vary by dive
population: 0.015% for scientific divers, 0.01�0.019% for recreational divers,
0.030% for U.S. Navy divers, and 0.095% for commercial divers (Savioli et al., 2022). This figure is
much higher when diving in cold water than in warm water. These figures are all
based on many dives done well within the maximum exposure limits of the
accepted procedure (decompression table or computer); therefore, these data
underestimate the actual level at the maximum limit. In addition, for long-term
exposure in hot conditions and stressful sports, the U.S. Navy's trial dive
aims to develop a new decompression procedure having a rate of 4.4 DCS cases
per 100 dives (Savioli et al., 2022) (Atwell et al., &; Cooper, 2019).
Pathophysiology of
DCS
����������� The physical law that most underlies
adaptive change and the development of decompression pathology and how to
overcome it is Henry's law (Henry's Law). This law, formulated by
William Henry in 1803, states that "a gas exerting pressure on the surface
of a liquid shall enter into the solution until it reaches the same pressure in
the liquid as the pressure exerted on that surface." According to this
law, at a constant temperature, the solubility of a gas is directly
proportional to the pressure that the gas exerts on the solution (Savioli et al., 2022).
Figure
2.2. Henry's Law
(Source:
Savioli and colleagues)
����������� Once equilibrium is reached, the
liquid is defined as saturated with that gas. When the pressure increases,
another gas will enter the solution, while when the pressure decreases, the
liquid will be in a saturated situation. The gas will be released to the
outside until the pressure is balanced again. According to this principle, when
the environmental pressure decreases during decompression, the tissue becomes
saturated with an inert gas, and therefore, the gas tends to leave the solution
and form a free gas. Due to the metabolic activity of oxygen and carbon
dioxide, oxygen saturation and carbon dioxide rarely contribute to the
formation of phases (Savioli et al., 2022) (Edge & Wilmshurst, 2021).
����������� Since transferring gases into the
grid is a dynamic process, it takes time to balance the grid and the
environmental partial pressure of the inert gas. Some time is required to
achieve equilibrium of tissue gas concentration at a specific pressure. Inert
gases escaping the tissue follow a similar kinetic pattern when the ambient
pressure decreases. Studies have shown gradual decompression with a set pause
can minimize saturation levels. Mathematical models regarding different types
of tissues and gases have been developed to explain this step, and valuable
tables have been created to determine the decompression time. It should be
noted that, due to this principle, reaching a certain altitude level (for
example, flying in a commercial aircraft) within 12-18 hours after diving can
result in the formation of free gases in the tissues, even following
established protocols for safety. Decompress (Hadanny et al., 2015).
����������� When returning to atmospheric
pressure from increasing the surrounding pressure, organisms now in a
nitrogen-saturated state need sufficient time to remove this inert gas. Inert
gases carried with inhaled air have indeed been dissolved in tissues, especially
in lipid-containing tissues (adipose tissue and myelin sheath), in amounts
directly proportional to environmental stress and exposure time (Edge & Wilmshurst, 2021) (Cialoni et al., 2017).
����������� The decompression table is
elaborated based on biological, mathematical models calculating the time
required to remove saturated nitrogen quotas without biological damage. Failure
to respect and determine the pathogenetic moment of the decompression syndrome.
Nitrogen is released in the gas phase, forming bubbles in the cellular,
interstitial fluid, and circulation environment, which can cause embolism. At
the interface with interstitial fluid and plasma, bubbles can also indirectly
activate intrinsic coagulation pathways, platelet aggregation, and factors
responsible for the inflammatory cascade (Savioli et al., 2022).
Figure
2.3. Pathophysiology of DCS
(Source:
Savioli and colleagues)
Clinical
manifestations
����������� Decompression sickness (Decompression
Sickness/DCS) is an acute attack. However, the onset time of symptoms
varies from individual to individual, and although signs and symptoms generally
occur within two hours after activity in an environment with higher pressure
than atmospheric (hyperbaric) environments, it can last from a few minutes to
24 to 48 hours. Most cases of DCS occur as soon as they surface, with 98%
occurring within 24 hours. However, the clinical picture may appear after 48
hours in some rare cases. This situation resembles scuba dives performed with a
self-contained breathing apparatus (ARA or SCUBA-AIR). Decompression sickness (Decompression
Sickness/DCS) can also occur after exposure to high pressure or rapid
pressure loss in the aircraft cabin.
����������� Bert was the first to describe the
pathophysiology of DCS in his milestone"La Pression Barometrique,"
published in 1878. Furthermore, in the early 20th century, autopsy studies on
divers and caisson patients showed that DCS was caused by free gas in blood and
tissues. Hallenbeck later became the first to show that platelet activation,
coagulation, and impaired capillary permeability (with plasma leakage into the
extravascular) correlate with bubble surface activity.
DCS Type 1:
Involvement of the Skin, Musculoskeletal, and Lymphatic System
����������� Type DCS 1 is the most common type
of DCS and causes joint pain that is often mistaken for pain from injury. It is
the mildest DCS, with no neurological, cardiovascular, or respiratory symptoms
present. Patients may complain of general lethargy, asthenia, and fatigue. The
most common manifestation is joint pain, which stems from the fact that
movement of the bones of the head can cause negative pressure, thereby
attracting gas bubbles. The shoulders and elbows are the most commonly involved
joints. Myalgia of varying localization is also common, and this condition is
an expression of activation of nitrogen-mediated inflammatory circuits.
Symptoms of musculoskeletal involvement may disappear within a few hours or
persist for 4-5 days. A previous history of musculoskeletal DCS increases the
risk of osteonecrosis (Howle et al., 2017).
����������� Osteonecrosis can occur in divers
who experience deep exposure caisson, diving instructors, and commercial
divers. Additional and less frequent presentations involve the cutaneous and
lymphatic systems, which can cause itching, marble formation, and puffy skin
with an orange-peel-like appearance. One form of particular skin involvement is
cutis marmorata, which usually appears as itchy or painful red or blue
patches. It is generally considered a mild form of DCS and requires
high-pressure recompression therapy. This condition can be treated with oxygen
inhalation. A patent foramen ovale has been observed associated with the
presence of patent foramen ovale (PFO) in the heart, with a prevalence
of almost 100%. Cutis marmorata rarely has other symptoms of DCS. These
symptoms are usually blurred vision, dizziness, and mild vagus or systemic
brain disorders (abnormal fatigue, stiffness, poor concentration, etc.). The
etiology of these other symptoms is embolic, and cutis marmorata can also be a
symptom of gas bubbles that embolic into the brainstem. Site of regulation of
skin blood vessels for dilation and contraction of the skin by the autonomic
nervous system (Sharareh & Schwarzkopf, 2015).
DCS Type 2:
Nervous, Cardiovascular, and Pulmonary System Involvement
����������� This type is a severe, though less
common, form of DCS and can cause permanent damage and, in rare cases, death.
The spinal cord is the most common site affected by DCS type II. Symptoms
resemble spinal cord trauma and usually involve the lumbar spine or lower back.
Its onset is often characterized by paresthesia and strength deficits up to
paraplegia, neurological bladder, intestinal or bladder incontinence, and
sexual impotence. When DCS affects the brain, many symptoms can appear, and the
clinical picture may be dominated by ataxia, nystagmus, visual impairment,
language disorders, behavioral changes, seizures, and even coma. These
manifestations usually result from deep and prolonged dives and often result in
permanent deafness (Jain et al., 2017).
����������� Heart or respiratory symptoms begin
with retrosternal depression or pain associated with cough or dyspnea. In some
cases, bronchospasm may occur. The changes that occur in the case of pulmonary
circulation embolization are characteristic of acute pulmonary heart failure
and right heart failure. In some cases, right heart failure can lead to coma or
death. Embolization of coronary arteries or large heart cavities can also cause
a heart attack (Savioli et al., 2022).
����������� Pulmonary vascular obstruction
usually occurs when large amounts of gas transit in the venous system.
Clinically, this causes chest pain, dyspnea, and coughing. This presentation
occurs in about 2% of all DCS cases and can eventually lead to death. Symptoms
can appear up to 12 hours after diving and last 12�48 hours. Pulmonary
barotrauma may be associated with DCS type 2 with pulmonary involvement in
cases of rapid ascent (Savioli et al., 2022).
Management
����������� Since the presence and detection of
gas embolism is usually the first evidence of the presence of free gas,
examination of the pulmonary artery with a Computed Tomography (CT)
Scan of The thorax can be used to detect it. Further, examination Ultrasonography
(Ultrasound) can also be useful (Savioli et al., 2022).
����������� In the form of DCS with immediate
attack, the first intervention can be carried out at the scene of the
decompression accident and mainly includes the support of vital functions
following the general guidelines for cardiopulmonary resuscitation. Oxygen needs
to be administered as soon as possible with an oronasal mask on FiO2
= 1, and the absence of nitrogen in the mixture favors its elimination by the
body (Savioli et al., 2022).
����������� The administration of intravenous or
oral fluids to conscious patients to expand the volume and improve blood
rheology should be considered from the outset. During hospitalization, the
already described action can be integrated with administering nonsteroidal
anti-inflammatory drugs, which are helpful in arthralgic manifestations. Some
research suggests that additional interventions, such as nonsteroidal
anti-inflammatory drugs (NSAIDs) or recompression with helium in addition to
oxygen, may reduce the recompression time required. For example, the use of
NSAIDs reduces the average number of recompression sessions required from three
to two. The use of either of these strategies may be justified. More research
is needed. Antiplatelet agents, such as aspirin, may be given to counteract
platelet activation caused by free gases in the blood and for their ability to
counteract increased platelet and erythrocyte aggregation (Jain et al., 2017).
����������� In case of neurological bladder
development, a bladder catheter needs to be installed. Transportation of
patients to centers equipped with hyperbaric implants must be prepared quickly.
Aerial vehicles require pressurized cabins or low-altitude flights to avoid
further decompression of the patient.
����������� Therapeutic recompression, which
means the delivery of 100% oxygen for several hours in an enclosed room
pressurized >1 atmosphere, slowly lowering the pressure to atmospheric
pressure, may be necessary and has three primary purposes (Brackett, 2019)
1) Reduces
the volume of bubbles present in the body, following Boyle's Law, and thus
reduces embolic resistance to blood flow. This will reduce the total surface of
the bubble with the consequent reduction of interaction with intercellular
fluid and plasma and, in turn, reduce the activation of clotting, platelet
aggregation, and inflammatory processes;
2) Increases
the absorption of bubbles in body fluids and the removal of inert gases from
the lungs through the dissolution of nitrogen present in the bubbles (Henry's
Law);
3) Improves
oxygen supply to peripheral tissue cells.
DCS Risk Factors
����������� Several risk factors have been
identified to increase the incidence of DCS. However, some of the mechanisms
are still being researched today. DCS risk factors, especially when diving, can
be divided into risk factors derived from the individual himself and
environmental factors that may play a role.
Individual Risk
Factors
1) Smoke
����������� Smokers are exposed to toxic
chemicals in cigarettes, especially carbon monoxide (CO), which binds tightly
with hemoglobin in the blood, reducing the blood's ability to transport oxygen.
This condition can impair blood and oxygen flow to tissues, including those
affected by DCS. In addition, smoking has been shown to damage the lungs and
cause a decrease in lung capacity, thereby reducing the body's ability to
remove dissolved gases, including nitrogen, during decompression. This can
increase the risk of gas bubbles forming in the body further during
decompression. Nevertheless, the results suggest that the pros and cons of
smoking as a significant risk factor in the increased incidence of DCS.
����������� The study conducted by Buch and
colleagues used DCI reports recorded in a database called Divers Alert
Network (AND) from 1989 to 1997 and evaluated the association of smoking
status with DCS/DCI severity. A total of 4,350 patients were included in the
analysis, the results showed that heavy smokers were more likely to experience
severe vs. mild symptoms than nonsmokers (OR = 1.88) (95% CI 1.36, 2.60) or
light smokers (OR = 1.56) (95% CI 1.09, 2.23). Heavy smokers and light smokers
were more likely than nonsmokers to experience severe vs. moderate symptoms (OR
= 1.36) (95% CI 1.06, 1.74) and (1.22) (1.02, 1.46). Study results are
consistent with the trend that when DCS occurs, smoking triggers more severe
symptoms.23 In contrast to the results of studies conducted by Duke and
colleagues, smoking, alcohol consumption, and obesity were not shown to be risk
factors influencing the incidence of DCS in divers (Duke et al., 2016).
2) Drink
alcohol the night before diving.
����������� Alcohol can cause dilation of blood
vessels (vasodilation), which can increase blood flow to tissues. This
condition can cause an increase in the pressure of blood-soluble gases, such as
nitrogen, during a dive. This gas can escape from the solution when
decompression occurs and form bubbles. Alcohol can also impair coordination and
judgment, which can lead to riskier diving behaviors and poor decisions, such
as increased dive depth without adhering to the correct decompression table.
����������� In a study Kongkamol and colleagues
conducted, conducted on fishermen divers in Thailand, examined that Body mass
index (BMI), alcohol consumption, diving depth, and duration of time at
sea/diving were significantly associated with DCS (p < 0.05) (Kongkamol et al., &; Sathirapanya, 2023).
3) Gender
����������� The debate over gender risk factors
has been ongoing for the past few years. Initially, the increased risk of
male-sex-related DCS was due to the prevalence of divers who were more dominant
were men. However, the increased interest of recreational divers in women
changes the risk rate for DCS events. Studies conducted by Webb, Kannan, and
Pilmanus showed no significant differences in the sexes regarding incidence
rates. However, precordial venous gas embolism (VGE) occurs much higher in men
than women under the same exposure conditions of 69.3% and 55.0%. Women who
used hormonal contraceptives showed a much greater susceptibility to DCS than
those who did not use hormonal contraceptives during the last two weeks of
their menstrual cycle (Jain et al., 2017).
4) Previous
DCS History
����������� Individuals who have experienced DCS
before have a higher risk of experiencing DCS again in subsequent dives. This
factor can be related to the susceptibility of individuals to pressure changes
and the development of gas bubbles in their bodies. Obesity can exacerbate this
risk if more nitrogen is stored in body tissues.
5) Obesity
����������� Obese individuals have a higher
accumulation of body fat, including in specific tissues such as cartilage and
adipose tissue (fat). Body fat is more capable of absorbing gases, including
nitrogen, that can cause DCS. As a result, fatter individuals may have more
significant nitrogen reserves in their bodies after a dive, which can increase
the risk of DCS.
����������� Obesity can affect the body's
metabolism, including dissolving and eliminating gases in the blood and
tissues. This disruption in metabolism can affect how the body handles
dissolved gases during and after the dive, increasing the likelihood of DCS.
Obesity is often linked to health problems such as high blood pressure and
heart disease. Pre-existing cardiovascular conditions can affect the body's
response to pressure changes during and after a dive. Further, this condition
can affect blood circulation and gas distribution, potentially increasing the
risk of DCS. Obesity can also affect an individual's breathing patterns.
Inefficient or shallow breathing during a dive can result in nitrogen
deposition in body tissues. If not removed correctly during the decompression
process, nitrogen can form gas bubbles that potentially carry a DCS risk.
6) Anxiety/panic
disorder
����������� Anxiety and panic disorders have the
potential to interact with DCS in a variety of ways, mainly because of the
psychological and physiological responses they trigger. Anxiety and panic
disorders often involve an increased stress response. Stress can affect overall
body functions, including the cardiovascular system. When individuals with
anxiety disorders experience stress before or during diving, this can lead to
changes in breathing patterns and increased heart rate, potentially affecting
their susceptibility to DCS.
����������� Anxiety and panic attacks are often
associated with rapid, shallow breathing or hyperventilation. Maintaining the
correct breathing pattern is essential during diving, especially in deep or
prolonged dives. Hyperventilation can lower carbon dioxide levels in the body,
potentially increasing the risk of DCS by altering gas exchange dynamics.
People with anxiety disorders may be more alert or risk-averse in their diving
practices. This can have both positive and negative impacts. Additionally, they
may be more diligent in following safety protocols and adhering to strict dive
table or dive computer recommendations. Excessive opposing sides can lead to
lost opportunities for a pleasant and safe diving experience.
����������� Individuals with anxiety or panic
disorders are often well aware of their physical sensations. This increased
awareness can sometimes lead to a tendency to misinterpret normal bodily
sensations as a sign of DCS or other health problems. This has the potential to
cause unnecessary worry or overreaction. Panic attacks while diving can be
hazardous, as they can interfere with a diver's ability to make rational
decisions and follow emergency procedures. Panic can lead to rapid ascent or
other unsafe behaviors that increase the risk of DCS.
����������� People with anxiety or panic
disorders who wish to dive should consult a mental health professional and dive
medicine professional. They may benefit from strategies for managing anxiety
before and during diving, such as relaxation techniques or cognitive behavioral
therapy. Medications used to treat anxiety may also be considered. However,
their effects on dive safety should be thoroughly discussed with a healthcare
provider.
7) Poor
Cardiorespiratory Fitness
����������� Poor cardiorespiratory fitness
refers to a physical condition in which a person has low cardiorespiratory
capacity. This includes the capacity of the lungs to transport oxygen, the
capacity of the heart to pump blood, and the body's ability to use oxygen
efficiently. When a person is not in good fitness, his body may not be able to
cope well with the pressure changes that occur during diving. This is because
changes in underwater pressure can affect blood circulation, tissue
oxygenation, and nitrogen release from tissues. In poor fitness conditions, the
body may be more susceptible to nitrogen accumulation in tissues, increasing
the risk of DCS.
8) Old
age
����������� As a person ages, several
physiological changes occur in his body. One is a decrease in the elasticity of
tissues, including lungs and blood vessels. This can affect,t the body's
ability to adjust to pressure changes that occur during diving. In addition,
old age is often a risk factor for specific medical conditions, such as
atherosclerosis, which can impede blood flow and affect gas exchange in the
body. All of these can contribute to an increased risk of DCS in older divers.
9) Disorders
or comorbidities that affect the efficiency of the lungs and blood vessels
����������� Disorders or diseases that affect
the efficiency of the lungs and blood vessels can be a significant risk factor.
For example, Chronic Obstructive Pulmonary Disease (COPD) or asthma can
interfere with airflow and gas exchange in the lungs. The presence of foramen
ovale is a risk factor for developing DCS in divers because it allows entry of
venous embolism into the systemic circulation. The fetus may be at risk for DCS
in pregnant divers. Pulmonary filters do not work in the fetus. Bubbles
produced by fetal tissue or placenta will pass through the foramen ovale into
the fetal arterial circulation, where they can cause embolism of the brain,
spinal cord, and other organs.
10) Previous
Musculoskeletal injuries
����������� Previous musculoskeletal injuries,
especially those involving joints or bones, can increase the risk of DCS. The
injury may cause the presence of areas that are prone to the development of gas
bubbles. When the pressure changes during the dive, this area can become a
potential source for gas bubbles to form. In addition, musculoskeletal injuries
can also affect blood circulation around the injury area, which can worsen the
risk of DCS. The study, conducted by Gottschalk and colleagues, states that
experimental rats that experience musculoskeletal injury have a significantly
increased risk of developing DCS compared to controls. Human studies have yet
to come up with conclusive conclusions, which could be due to a lack of
historical examination of previous injuries.
11) High-fat
diet
����������� Kaczerska and colleagues, in their
study on the effect of postprandial hypertriglyceridemia on the risk of
decompression stress after exposure to hyperbaric air, reported that after each
hyperbaric exposure, decompression stress was found in 30 of the 55 subjects.
Postprandial hypertriglyceridemia and hypercholesterolemia increase the risk of
stress decompression after exposure to hyperbaric air.
����������� A diet high in fat, mainly if it
contains saturated fat and high cholesterol, can affect the nature of the
blood. High levels of fats in the blood can affect blood viscosity, which means
the blood becomes thicker. Thicker blood can impede blood flow to tissues and
organs, affecting the body's ability to cope with pressure changes during a
dive. In addition, thicker blood can also increase the risk of blood clot
formation, clogging tiny blood vessels and triggering circulation problems. All
of these can affect the body's response to DCS.
Environmental
Factors
1) Cold
Exposure After Diving/Diver Cold during Recompression
����������� After diving, the body generally
becomes cooler because water has a high heat conductivity. When a person does
not wear appropriate clothing or does not maintain their body temperature, the
risk of hypothermia increases. Hypothermia can affect blood flow and metabolism
and the body's ability to remove dissolved gases, such as nitrogen, during
decompression.
2) Cold
water (vasoconstriction lowers nitrogen removal)
����������� Cold water can have a significant
impact on a diver's body. When exposed to low water temperatures, blood vessels
in the skin will narrow (vasoconstriction) in response to maintaining body
heat. This vasoconstriction aims to reduce blood flow to the skin and
prioritize blood flow to essential core organs, such as the heart and brain.
During the dive, nitrogen from the air inhaled by the diver will dissolve in
the body tissues. As divers rise to the surface, environmental pressure
decreases, allowing this dissolved nitrogen to escape the tissue as bubbles. If
the body experiences significant vasoconstriction due to cold water, blood flow
to peripheral tissues (such as the skin) may be reduced more. This means that
peripheral areas may experience a more significant decrease in blood flow,
making the release of nitrogen from tissues slower. As a result, more nitrogen
bubbles may form and risk causing DCS.
3) Poor
sea conditions, heavy currents
����������� Poor ocean conditions with heavy
currents can provide additional challenges for divers. Strong ocean currents
can force divers to make extra efforts to stay in the desired position,
allowing the body to expend energy and produce more nitrogen in the tissues. In
addition, poor ocean conditions often mean divers will spend more time
underwater, which can increase pressure on body tissues and affect
decompression.
4) Heated
wetsuit (causes dehydration and increases nitrogen upload)
����������� A heated wetsuit is a device to
maintain a diver's body temperature underwater, especially in cold water.
However, using heated wetsuits also has side effects to be aware of. One effect
is the potential for dehydration. While in a wetsuit, divers may feel more
comfortable and less aware that they are still losing body fluids through sweat
and breathing. Dehydration can cause blood to become thicker, affecting blood
circulation and releasing nitrogen from tissues as it rises to the surface. In
addition, when a person feels comfortable in a heated wetsuit, they tend to
spend more time underwater, which allows for more excellent nitrogen absorption
in tissues.
5) Depth
and Duration of Dive
����������� The depth and duration of the dive
play an essential role in DCS risk assessment, as more profound and longer
dives increase the likelihood of this condition occurring. The speed at which
divers rise from the depths is equally important, with rapid surfaces
increasing susceptibility to DCS due to pressure fluctuations.
1. Decompression
sickness (DCS) occurs when dissolved gases (usually nitrogen or helium,
used in mixed gas diving) escape from the solution and form bubbles in the body
when the pressure drops. DCS can occur during underwater dives (at the time of
elevation), while working in kaisons, flying in unpressurized aircraft, and
doing activities outside the spacecraft.
2. Experts
categorize DCS into Type I, with symptoms involving the skin, musculoskeletal
system, or lymphatic system only, and Type II, with symptoms involving the
central nervous system.
3. Risk
factors for DCS events can be classified into individual and environmental
factors. Individual factors include obesity, smoking, alcohol consumption
before diving, poor cardiorespiratory fitness, patency of the foramen ovale,
high-fat diet and dyslipidemia, old age, disorders or diseases affecting lung
and blood vessel efficiency, previous musculoskeletal injuries, and
anxiety/panic disorders. Environmental factors include cold water temperature,
exposure to cold/cold during recompression, heavy ocean currents, heated
wetsuits, and depth and duration of diving.
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