Barotrauma
Encyclopedia
Barotrauma is physical damage to body tissues caused by a difference in pressure
between an air space inside or beside the body and the surrounding fluid
. In addition to humans, and in contrast with Avian lungs, bats suffer fatal barotrauma around wind farms.
Barotrauma typically occurs to air spaces within a body when that body moves to or from a higher pressure environment, such as when a SCUBA diver
, a free-diving
diver or an airplane passenger ascends or descends, or during uncontrolled decompression of a pressure vessel
. Boyle's law
defines the relationship between the volume
of the air space and the ambient pressure
.
Damage occurs in the tissues around the body's air spaces because gases are compressible and the tissues are not. During increases in ambient pressure, the internal air space provides the surrounding tissues with little support to resist the higher external pressure. During decreases in ambient pressure, the higher pressure of the gas inside the air spaces causes damage to the surrounding tissues if that gas becomes trapped.
. External ear barotrauma may occur on ascent if high pressure air is trapped in the external auditory canal either by tight fitting SCUBA equipment or ear wax. Inner ear barotrauma (IEBT) though much less common than MEBT shares a similar mechanism. Mechanical trauma to the inner ear can lead to varying degrees of conductive
and sensorineural hearing loss
as well as vertigo
.
s.
of a pressurised aircraft.
differences needed to cause the barotrauma come from two sources:
Following barotrauma of the ears or lungs from diving the diver should not dive again until thoroughly cleared by a doctor, which can take many months. Life effects of Barotrauma at the American Hearing Research Foundation
Use of a hyperbaric chamber. Patients undergoing hyperbaric oxygen therapy
must learn to equalize in order to avoid barotrauma. Some patients may be at greater risk of otic barotrauma than others.
and explosive decompression create a pressure wave that can induce barotrauma. The difference in pressure between internal organs and the outer surface of the body causes injuries to internal organs that contain gas, such as the lung
s, gastrointestinal tract
, and ear
.
Lung injuries can also occur during rapid decompression, although the risk of injury is lower than with explosive decompression.
can lead to barotrauma of the lungs. This can be due to either:
The resultant alveolar rupture can lead to pneumothorax
, pulmonary interstitial emphysema (PIE) and pneumomediastinum
.
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
between an air space inside or beside the body and the surrounding fluid
Fluid
In physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
. In addition to humans, and in contrast with Avian lungs, bats suffer fatal barotrauma around wind farms.
Barotrauma typically occurs to air spaces within a body when that body moves to or from a higher pressure environment, such as when a SCUBA diver
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
, a free-diving
Free-diving
Freediving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spear fishing, freedive photography, apnea competitions and, to a degree, snorkeling...
diver or an airplane passenger ascends or descends, or during uncontrolled decompression of a pressure vessel
Pressure vessel
A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...
. Boyle's law
Boyle's law
Boyle's law is one of many gas laws and a special case of the ideal gas law. Boyle's law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system...
defines the relationship between the volume
Volume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
of the air space and the ambient pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
.
Damage occurs in the tissues around the body's air spaces because gases are compressible and the tissues are not. During increases in ambient pressure, the internal air space provides the surrounding tissues with little support to resist the higher external pressure. During decreases in ambient pressure, the higher pressure of the gas inside the air spaces causes damage to the surrounding tissues if that gas becomes trapped.
Types of injury
Examples of organs or tissues easily damaged by barotrauma are:- middle earMiddle earThe middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...
(barotitis or aerotitis) - paranasal sinusParanasal sinusParanasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
es (causing AerosinusitisAerosinusitisAerosinusitis, also called barosinusitis, sinus squeeze or sinus barotrauma is a painful inflammation and sometimes bleeding of the membrane of the paranasal sinus cavities, normally the frontal sinus...
) - lungsHuman lungThe human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately of airways and 300 to 500 million alveoli, having a total surface area of about in...
- eyes (the unsupportive air space is inside the diving maskDiving maskA diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. When the human eye is in direct contact with water as opposed to air, its normal environment, light entering the eye is refracted by a different angle and the eye is unable...
) - skinSkin-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
(when wearing a diving suitDiving suitA diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit typically also incorporates an air-supply .-History:...
which creates an air space) - boneBoneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
(bone necrosis and temporal lobe injury) - Teeth (causing BarodontalgiaBarodontalgiaBarodontalgia, commonly known as tooth squeeze and previously known as aerodontalgia, is a pain in tooth caused by a change in atmospheric pressure...
, i.e. barometric pressure related dental painToothacheA toothache, also known as odontalgia or, less frequently, as odontalgy, is an aching pain in or around a tooth.-Causes:* Dental etiology, In most cases toothaches are caused by problems in the tooth or jaw, such as** Dental caries...
, or dental fractures)
Ear barotrauma
Barotrauma can affect the external, middle, or inner ear. Middle ear barotrauma (MEBT) is the most common being experienced by between 10% and 30% of divers and is due to insufficient equilibration of the middle earEar clearing
Ear clearing or clearing the ears is any of various maneuvers to equalize the pressure in the middle ear with the outside pressure, by letting air enter along the Eustachian tubes, as this does not always happen automatically when the pressure in the middle ear is lower than the outside pressure...
. External ear barotrauma may occur on ascent if high pressure air is trapped in the external auditory canal either by tight fitting SCUBA equipment or ear wax. Inner ear barotrauma (IEBT) though much less common than MEBT shares a similar mechanism. Mechanical trauma to the inner ear can lead to varying degrees of conductive
Conductive hearing loss
Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane , or middle ear ....
and sensorineural hearing loss
Sensorineural hearing loss
Sensorineural hearing loss is a type of hearing loss in which the root cause lies in the vestibulocochlear nerve , the inner ear, or central processing centers of the brain....
as well as vertigo
Vertigo (medical)
Vertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...
.
Barosinusitis
The sinuses similar to other air filled cavities are susceptible to barotrauma if their openings become obstructed. This can result in pain as well as epistaxis.Mask squeeze
If a diver's mask is not equalized during descent the relative negative pressure can produce petechial hemorrhages in the area covered by the mask along with subconjunctival hemorrhageSubconjunctival hemorrhage
thumb|right|250px| A stress induced subconjunctival hemorrhage in the left eye one week after hemorrhaging. Same hemorrhage four weeks after hemorrhaging. Some of the blood in the [[sclera]] has turned yellow, like a bruise....
s.
Pulmonary barotrauma
Pulmonary (lung) pressure damage in scuba divers is usually caused by breath-holding on ascent. The compressed gas in the lungs expands as the ambient pressure decreases causing the lungs to over expand and rupture unless the diver breathes out. The lungs do not sense pain when over-expanded giving the diver little warning to prevent the injury. This does not affect breath-hold skin divers as they bring a lungfull of air with them from the surface, which merely re-expands safely to near its original volume on ascent. The problem only arises if a breath of compressed gas is taken at depth, which will then expand on ascent to more than the lung volume. Pulmonary barotrauma may also be caused by explosive decompressionExplosive decompression
Uncontrolled decompression refers to an unplanned drop in the pressure of a sealed system, such as an aircraft cabin and typically results from human error, material fatigue, engineering failure or impact causing a pressure vessel to vent into its lower-pressure surroundings or fail to pressurize...
of a pressurised aircraft.
Causes
When diving, the pressurePressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
differences needed to cause the barotrauma come from two sources:
- descending and ascending in water. There are two components to the surrounding pressure acting on the diver: the atmospheric pressureAtmospheric pressureAtmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
and the water pressure. A descent of 10 metres (33 feet) in water increases the ambient pressure by approximately the pressure of the atmosphere at sea level. So, a descent from the surface to 10 metres (33 feet) underwater results in a doubling of the pressure on the diver. - breathing gas at depth from SCUBA equipmentScuba setA scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
results in the lungs containing gas at a higher pressure than atmospheric pressure. So a free-divingFree-divingFreediving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spear fishing, freedive photography, apnea competitions and, to a degree, snorkeling...
diver can dive to 10 metres (33 feet) and safely ascend without exhaling, because the gas in the lungs had been inhaled at atmospheric pressure, whereas a SCUBA diverScuba divingScuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
who breathes at 10 metres and ascends without exhaling has lungs containing gas at twice atmospheric pressure and is very likely to suffer life-threatening lung damage.
Avoidance and treatment
Diving barotrauma can be avoided by eliminating any pressure differences acting on the tissue or organ by equalizing the pressure. There are a variety of techniques:- The air spaces in the earEarThe ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
s, and the sinusesParanasal sinusParanasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity , above and between the eyes , and behind the ethmoids...
. The risk is burst eardrumEardrumThe eardrum, or tympanic membrane, is a thin membrane that separates the external ear from the middle ear in humans and other tetrapods. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles...
. Here, the diver can use a variety of methodsEar clearingEar clearing or clearing the ears is any of various maneuvers to equalize the pressure in the middle ear with the outside pressure, by letting air enter along the Eustachian tubes, as this does not always happen automatically when the pressure in the middle ear is lower than the outside pressure...
, to let air into the middle earMiddle earThe middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...
s via the Eustachian tubeEustachian tubeThe Eustachian tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi...
s. Sometimes swallowing will open the Eustachian tubes and equalise the ears. - The lungHuman lungThe human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately of airways and 300 to 500 million alveoli, having a total surface area of about in...
s. The risk includes pneumothoraxPneumothoraxPneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...
, arterial gas embolism, and mediastinal and subcutanous emphysemasSubcutaneous emphysemaSubcutaneous emphysema, sometimes abbreviated SCE or SE and also called tissue emphysema, or Sub Q air, occurs when gas or air is present in the subcutaneous layer of the skin. Subcutaneous refers to the tissue beneath the cutis of the skin, and emphysema refers to trapped air...
. which are commonly called burst lung or lung overpressure injury by divers. To equalise, all that is necessary is not to hold the breath during ascent. This risk does not arise when snorkel diving from the surface, unless the snorkeller breathes from a high pressure gas source underwater, or from submerged air pockets. Some people have pathologies of the lung which prevent rapid flow of excess air though the passages, which can lead to lung barotrauma even if the breath is not held during rapid depressurisation. These people should not dive as the risk is unacceptably high. Most commercial or military diving medical examinations will look specifically for signs of this pathology. - The air inside the usual eyes-and-nose diving maskDiving maskA diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. When the human eye is in direct contact with water as opposed to air, its normal environment, light entering the eye is refracted by a different angle and the eye is unable...
(also known as a half mask). The main risk is bleeding around the eyes from the negative pressure or orbital emphysema from higher pressures. Here, let air into the mask through the nose. Do not dive in eyes-only gogglesGogglesGoggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well,...
as sometimes seen on land with industrial breathing sets. - Air spaces inside a dry suitDiving suitA diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit typically also incorporates an air-supply .-History:...
. The main risk is folds of skin getting pinched inside folds of the drysuit. Most modern drysuits have a tube connection to feed air in from the cylinder. Air must be injected on the descent and vented on the ascent.
Following barotrauma of the ears or lungs from diving the diver should not dive again until thoroughly cleared by a doctor, which can take many months. Life effects of Barotrauma at the American Hearing Research Foundation
Use of a hyperbaric chamber. Patients undergoing hyperbaric oxygen therapy
Hyperbaric oxygen therapy
Hyperbaric medicine, also known as hyperbaric oxygen therapy , is the medical use of oxygen at a level higher than atmospheric pressure. The equipment required consists of a pressure chamber, which may be of rigid or flexible construction, and a means of delivering 100% oxygen...
must learn to equalize in order to avoid barotrauma. Some patients may be at greater risk of otic barotrauma than others.
Blast induced barotrauma
An explosive blastExplosion
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
and explosive decompression create a pressure wave that can induce barotrauma. The difference in pressure between internal organs and the outer surface of the body causes injuries to internal organs that contain gas, such as the lung
Human lung
The human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately of airways and 300 to 500 million alveoli, having a total surface area of about in...
s, gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
, and ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
.
Lung injuries can also occur during rapid decompression, although the risk of injury is lower than with explosive decompression.
Ventilator induced barotrauma
Mechanical ventilationMechanical ventilation
In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...
can lead to barotrauma of the lungs. This can be due to either:
- absolute pressures used in order to ventilate non-compliant lungs.
- shearing forces, particularly associated with rapid changes in gas velocityVelocityIn physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
.
The resultant alveolar rupture can lead to pneumothorax
Pneumothorax
Pneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...
, pulmonary interstitial emphysema (PIE) and pneumomediastinum
Pneumomediastinum
Pneumomediastinum is a condition in which air is present in the mediastinum...
.
See also
- Alternobaric vertigoAlternobaric vertigoIn aviation and underwater diving, alternobaric vertigo is dizziness resulting from unequal pressures being exerted between the ears due to one Eustachian tube being less patent than the other.- Causes :...
- BarodontalgiaBarodontalgiaBarodontalgia, commonly known as tooth squeeze and previously known as aerodontalgia, is a pain in tooth caused by a change in atmospheric pressure...
- Bell's PalsyBell's palsyBell's palsy is a form of facial paralysis resulting from a dysfunction of the cranial nerve VII that results in the inability to control facial muscles on the affected side. Several conditions can cause facial paralysis, e.g., brain tumor, stroke, and Lyme disease. However, if no specific cause...
- Dental barotraumaDental barotraumaDental barotrauma is a condition in which barometric pressure changes in the external environment cause damage to the dentition. The problem can occur owing to a miniature void within a filled tooth. It is technically difficult to completely prevent void spaces occurring when placing a filling and...
- Diving hazards and precautionsDiving hazards and precautionsDivers face specific physical and health risks when they go underwater or use high pressure breathing gases. Some of these conditions also affect people who work in raised pressure environments out of water, e.g...
- DysbarismDysbarismDysbarism refers to medical conditions resulting from changes in ambient pressure. Various activities are associated with pressure changes. Scuba diving is the most frequently cited example, but pressure changes also affect people who work in other pressurized environments , and people who move...
- Jet ventilation
- MeteoropathyMeteoropathyMeteoropathy is a disorder, or physical condition, or symptom due to climate or conditions of weather such as humidity, temperature or pressure...
- Uncontrolled decompression
- Exothalima