Salt water aspiration syndrome | |
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Other names | Saltwater aspiration syndrome |
Specialty | Undersea medicine |
Symptoms | Cough, shortness of breath, chest discomfort, fever, malaise, shivering, headache, nausea |
Usual onset | Immediately after an underwater dive |
Duration | ~ 24 hours |
Causes | Lung inflammation caused by inhalation of salt water |
Diagnostic method | Clinical |
Treatment | Supplemental oxygen |
Salt water aspiration syndrome or saltwater aspiration syndrome is a medical condition caused by the inhalation or aspiration of small amounts of salt water, leading to lung irritation and inflammation. Unlike drowning or near-drowning, it does not involve ingestion of large volumes of water. It often results from faulty diving equipment or improper breathing techniques, allowing fine water droplets to reach the lower respiratory tract.
The condition often begins with cough and shortness of breath, followed by shivering, fever, and other systemic symptoms. It can resemble a viral infection but improves within hours, especially with supplemental oxygen. While most cases resolve on their own, severe instances may require critical care. Diagnosis is based on clinical history and symptom progression. Salt water aspiration syndrome was first described in 1970.
Salt water aspiration syndrome occurs when small amounts of salt water is inhaled or aspirated over time. [1] Hypertonic salt water, being more concentrated than human blood, creates an osmotic gradient when it enters the lungs. This gradient draws water out of surrounding lung tissues into the alveoli and bronchioles, leading to irritation and inflammation. Salt water can also cause oxidative stress, dilution of pulmonary surfactant, breakdown of the blood-air barrier, cellular degradation and cell death. [2] Marine microorganisms and particulates can further exacerbate inflammatory processes, which may cause or contribute towards systemic symptoms seen with this condition. [3]
Unlike drowning or near-drowning which involves sudden intake of large quantities of liquid, this condition can develop subtly over a prolonged period. Faulty diving equipment such as diving regulators, improper breathing techniques, or buddy breathing lead to the inhalation of fine salt water droplets. The small size of the droplets allows them to reach the lower respiratory tract without significantly triggering the upper airway's cough reflex, hence getting aspirated without causing immediate symptoms. [1]
Salt water aspiration syndrome often begins with an aspiration event. After completing an underwater dive, the first symptom is usually a cough, sometimes producing sputum that may be excessive or blood-tinged. Within the next two hours, divers may develop bluish skin, shortness of breath, increased respiratory rate, increased heart rate, chest discomfort and pain. [1] In rare but severe cases, low oxygen levels in blood and inflammation of lungs can occur. [4] Lungs auscultation may reveal abnormal breath sounds and chest imaging can show lung consolidations. [3] Blood work usually does not show specific abnormalities, but slightly elevated white blood cell count and lactate dehydrogenase levels may be seen. [1]
Salt water aspiration syndrome generally mimics symptoms of an acute viral infection. Fever, malaise and chills are most commonly reported, and usually the first systemic symptoms to appear. Most individuals experience tremors and shivering [5] [3] – the latter is often worse with reduced oxygen levels in blood. [6] Headaches are reported in about two-thirds of cases, while about one-third experience body aches. Gastrointestinal involvement can result in loss of appetite, nausea and vomiting. Less commonly, affected individuals experience fainting, temporary loss of consciousness and mild confusion. [1]
The diagnosis of salt water aspiration syndrome is based on medical history and physical examination. Its initial symptoms of cough and difficulty breathing are similar to near-drowning, however near-drowning does not cause viral infection-like symptoms. Furthermore it can be difficult to distinguish the condition from an acute viral infection at first; unlike viral illnesses however, salt water aspiration syndrome tends to improve within a few hours. [1]
The condition shares features with decompression sickness; a review of the dive profile and the absence of other symptoms associated with decompression can help distinguish between the two. Significant improvement following supplemental oxygen further supports the diagnosis of salt water aspiration syndrome. [A] Other diving conditions like pulmonary barotrauma, immersion pulmonary edema and low body temperatures can produce similar symptoms or occur alongside this syndrome; these can be distinguished through the clinical course and imaging results. [1]
Treatment involves supportive care with supplemental oxygen, observation and rest. [1] Most cases resolve within the first 24 hours, often spontaneously without treatment. [9] Critical care may be necessary for severe cases or cases complicated with underlying respiratory disorders. [4]
The condition was first described in 1970 by Carl Edmonds, who documented 30 cases at the Royal Australian Navy School of Underwater Medicine. [3] A 1989 study estimated that 37 percent of deaths that occurred during recreational scuba diving in Australia and New Zealand in the 1980s involved salt water aspiration syndrome. The study hypothesized—based on reports of the victims symptoms and an analysis of their equipments—that the syndrome acted as an intermediate factor, exacerbating panic and exhaustion, which subsequently led to loss of consciousness. [10] In 2019, a case study reported severe salt water aspiration syndrome caused by a beluga whale splash in an audience member during a show at Georgia Aquarium which required critical care. [4]
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.
A cough is a sudden expulsion of air through the large breathing passages which can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound.
Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other symptoms may include shortness of breath, cough, fever, or weight loss, depending on the underlying cause.
Pulmonary aspiration is the entry of solid or liquid material such as pharyngeal secretions, food, drink, or stomach contents from the oropharynx or gastrointestinal tract, into the trachea and lungs. When pulmonary aspiration occurs during eating and drinking, the aspirated material is often colloquially referred to as "going down the wrong pipe".
Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures. Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lungs, and eyes. Historically, the central nervous system condition was called the Paul Bert effect, and the pulmonary condition the Lorrain Smith effect, after the researchers who pioneered the discoveries and descriptions in the late 19th century. Oxygen toxicity is a concern for underwater divers, those on high concentrations of supplemental oxygen, and those undergoing hyperbaric oxygen therapy.
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with, the body and the surrounding gas or liquid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by an expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with the normal function of an organ by its presence. The term is usually applied when the gas volume involved already exists prior to decompression. Barotrauma can occur during both compression and decompression events.
In-water recompression (IWR) or underwater oxygen treatment is the emergency treatment of decompression sickness (DCS) by returning the diver underwater to help the gas bubbles in the tissues, which are causing the symptoms, to resolve. It is a procedure that exposes the diver to significant risk which should be compared with the risk associated with the available options and balanced against the probable benefits. Some authorities recommend that it is only to be used when the time to travel to the nearest recompression chamber is too long to save the victim's life; others take a more pragmatic approach and accept that in some circumstances IWR is the best available option. The risks may not be justified for case of mild symptoms likely to resolve spontaneously, or for cases where the diver is likely to be unsafe in the water, but in-water recompression may be justified in cases where severe outcomes are likely if not recompressed, if conducted by a competent and suitably equipped team.
Atelectasis is the partial collapse or closure of a lung resulting in reduced or absent gas exchange. It is usually unilateral, affecting part or all of one lung. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often referred to informally as a collapsed lung, although more accurately it usually involves only a partial collapse, and that ambiguous term is also informally used for a fully collapsed lung caused by a pneumothorax.
Chemical pneumonitis is inflammation of the lung caused by aspirating or inhaling irritants. It is sometimes called a "chemical pneumonia", though it is not infectious. There are two general types of chemical pneumonitis: acute and chronic.
Hyperoxia is the state of being exposed to high levels of oxygen; it may refer to organisms, cells and tissues that are experiencing excessive oxygenation, or to an abnormally high oxygen concentration in an environment.
Diving disorders, or diving related medical conditions, are conditions associated with underwater diving, and include both conditions unique to underwater diving, and those that also occur during other activities. This second group further divides conditions caused by exposure to ambient pressures significantly different from surface atmospheric pressure, and a range of conditions caused by general environment and equipment associated with diving activities.
Viral pneumonia is a pneumonia caused by a virus. Pneumonia is an infection that causes inflammation in one or both of the lungs. The pulmonary alveoli fill with fluid or pus making it difficult to breathe. Pneumonia can be caused by bacteria, viruses, fungi or parasites. Viruses are the most common cause of pneumonia in children, while in adults bacteria are a more common cause.
Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who have recently visited a hospital or who live in long-term care facilities. CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung (alveoli) filling with fluid. This inhibits lung function, causing dyspnea, fever, chest pains and cough.
Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.
Pneumonia is an irritation of the lungs caused by different sources. It is characterized by an inflammation of the deep lung tissues and the bronchi. Pneumonia can be acute or chronic. This life-threatening illness is more common in cats than in dogs and the complication “Kennel Cough” can occur in young pets.
Freediving blackout, breath-hold blackout, or apnea blackout is a class of hypoxic blackout, a loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive, when the swimmer does not necessarily experience an urgent need to breathe and has no other obvious medical condition that might have caused it. It can be provoked by hyperventilating just before a dive, or as a consequence of the pressure reduction on ascent, or a combination of these. Victims are often established practitioners of breath-hold diving, are fit, strong swimmers and have not experienced problems before. Blackout may also be referred to as a syncope or fainting.
Latent hypoxia is a condition where the oxygen content of the lungs and arterial blood is sufficient to maintain consciousness at a raised ambient pressure, but not when the pressure is reduced to normal atmospheric pressure. It usually occurs when a diver at depth has a lung gas and blood oxygen concentration that is sufficient to support consciousness at the pressure at that depth, but would be insufficient at surface pressure. This problem is associated with freediving blackout and the presence of hypoxic breathing gas mixtures in underwater breathing apparatus, particularly in diving rebreathers.
Swimming induced pulmonary edema (SIPE), also known as immersion pulmonary edema, is a life threatening condition that occurs when fluids from the blood leak abnormally from the small vessels of the lung (pulmonary capillaries) into the airspaces (alveoli).
Scuba diving fatalities are deaths occurring while scuba diving or as a consequence of scuba diving. The risks of dying during recreational, scientific or commercial diving are small, and on scuba, deaths are usually associated with poor gas management, poor buoyancy control, equipment misuse, entrapment, rough water conditions and pre-existing health problems. Some fatalities are inevitable and caused by unforeseeable situations escalating out of control, though the majority of diving fatalities can be attributed to human error on the part of the victim.
Human physiology of underwater diving is the physiological influences of the underwater environment on the human diver, and adaptations to operating underwater, both during breath-hold dives and while breathing at ambient pressure from a suitable breathing gas supply. It, therefore, includes the range of physiological effects generally limited to human ambient pressure divers either freediving or using underwater breathing apparatus. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, the effects of breathing gases at raised ambient pressure, effects caused by the use of breathing apparatus, and sensory impairment. All of these may affect diver performance and safety.