Environmental Week
Reef Diving
Diving Emergencies By Cristian Danyow
Destination:Raja Ampat
A gorgeous archipelago located in Indonesia, known for its reef diving. Tourists and locals alike routinely embark on dives ranging from 15-130'. This is the location I will be headed to for my dream vacation, to enjoy some vitamin D, salt water, and mai tais. Click on each picture for a closer look at this tropical paradise.
Environmental Emergencies
Above the surface of the water
As beautiful as this place may be, we always have to be wary of our surroundings above and below the water. Click around and see what kind of environmental factors you may encounter on the surface and potential diving emergencies that even experienced divers may suffer from
Diving emergencies
Drowning
Hypothermia
Signs and symptoms of environmental emergencies on the surface are noted in this section.
Heat related emergencies
Surface Emergency Treatments
Injuries during ascent
Injuries during descent
Signs and symptoms of environmental emergencies that occur during scuba diving are noted in this section.
Injuries at the bottom
Diving Emergency Treatments
Long-Term Care
The bends
Nitrogen narcosis
OVerpressure
Henry's Law
The amount of gas dissolved in a given volume of fluid is proportional to the prssure of gas above it.
How does it work?
Function
Equation
Scientist
+ info
Click for an example of how Henry's law works and why it is important when discussing dive emergencies.
(P_{gas}=kC), where (P) is partial pressure, (C) is gas concentration, and (k) is the constant).
William Henry, an english physician and chemist discovered it in 1803.
Recap!
Body systems
How does Henry's Law interact with the body?
Nervous system
Cardiovascular
Respiratory
We need to interact with each other. We learn collaboratively.
We are able to understand images from millions of years ago, even from other cultures.
We tell thousands and thousands of stories. ⅔ of our conversations are stories.
Could we observe these symptoms on the vacation?
Hyperbaric
The bends
Gas Embolism
Citations
- Rublee, C., Dresser, C., Giudice, C., Lemery, J., & Sorensen, C. (2021, February 26). Evidence-based Heatstroke Management in the emergency department. The western journal of emergency medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC7972371/
- Avishay, D. M. (2023, January 29). Henry’s Law. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK544301/
- Gianfrancesco, H. (2025, September 15). Drowning: Clinical management. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK430833/
- Cooper, J. S. (2023, December 13). Decompression sickness. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK537264/
Thank you!
Nervous system
As we have learned, gases dissolve based on their partial pressures, but how does that affect the nervous system? The exchange of gases is regulated by chemoreceptors in the central and peripheral areas of the body. That means that gases like carbon dioxide are continuously monitored and control our respiratory drive. As the partial pressure of carbon dioxide increases, more carbon dioxide must be expelled and more must dissolve to restore homeostasis.
Respiratory
Henry's Law governs the solubility of gases in a liquid. In the respiratory system, we breathe oxygen into the lungs, and due to the pressure gradient this forces oxygen molecules to dissolve into the plasma, where they attach to hemoglobin sites on RBCs. In reverse, carbon dioxide is removed from the system according to the pressure gradient of the gas.
Cardiovascular
The cardiovascular system is what governs the transport of gases in the body. Without the contractions of the heart, there would be no movement. The partial pressures of the gases and their solubility determine the rate at which they dissolve. In decompression sickness, the pressure has increased so dramatically that the gases cannot be dissolved into the solution and form bubbles. These bubbles in the blood can obstruct blood flow and cannot readily dissolve back into plasma for excretion.
The Surface
Imagine you are in Indonesia, a tropical environment, the sun is beating down on you, and you have forgotten your water bottle. You have a long hike down the beach, and you have been ingesting too much alcohol. You could be susceptible to a heat-related emergency such as heat cramping, heat exhaustion, and heat stroke. Even effects from cold water or prolonged durations in the water. Or so you are getting ready for a dive out in this crystal clear water, you become panicked, fatigued, or lightheaded. Such situations may result in drowning if you are not careful. Accidents on the surface are possible if you have not clearly marked off a diving zone and other boats are driving nearby.
Diving
Even some of the most experienced divers in the world can make mistakes or get complacent. There are a few classifications of diving injuries that would complicate even the best vacation. Injuries that happen during the descent phase of the dive, resulting in barotrauma, where the pressure equilibration causes damage. Injuries while at the bottom result from nitrogen narcosis of the tissue, for those of us who like to take unnecessary risks. Injuries during the ascent phase that involve barotrauma can cause a multitude of potential injuries to the diver.
- Three classifications of hyperthermia: Heat (muscle) cramps, Heat exhaustion and Heat stroke.
- Heat cramps: caused by overexertion and dehydration. Excessive diaphoresis causes the loss of sodium and water, which causes muscle cramping. S/S: Cramping in fingers, arms, legs, and ABD. Dizziness and fatigue may be present. Body temperature may be normal or slightly elevated.
- Heat Exhaustion: Mild to moderate heat-related illness that is an acute reaction to heat exposure. Exertion in a high heat environment causes a loss of 1-2 L of water an hour, causing dehydration and electrolyte loss. S/S: Increased body temperature over 100 degrees F or 38.7 °C. Skin is cool/clammy, excessive diaphoresis, and rapid and shallow breathing. Weakness, dizziness, fatigue, and possible loss of consciousness.
- Heat Stroke: Hypothalamic regulation of body temperature control is lost, causing uncompensated hyperthermia. Causes cell death, kidney and liver damage, and possible brain damage . Usually characterized as at least 105°F or 40.6 °C. S/S: Diaphoresis has halted due to CNS disturbance, hot/dry skin, deep/shallow respirations, rapid pulse, hypotension, confusion, disorientation, unconsciousness, headache, paresthesia, agitation, hallucinations, possible seizures, and coma.
Hyperthermia
Hyperthermia is a relevant piece of the equation in any tropical location. High heat, sun penetration, and humidity are all factors in a paradise such as this. Hyperthermia is defined as a state of unusually high core body temperature, either from external factors (environment) or from pyrexia (infection). The body has thermoregulation centers called thermoreceptors in the skin and mucus membranes (peripheral) and deep tissues (central) that detect changes in the body's temperature. However, these receptors are most sensitive to cold temperatures. The way the body tries to cool itself down is through two ways, diaphoresis and vasodilation, which are signs of thermolysis.
Hypothermia
Hypothermia is defined as a low core body temperature below 95°F. Think about being out in the deeper water without the proper equipment to retain any body heat; the body is stripped of its heat due to conduction. When surrounded by a cold fluid, the body's mechanisms of thermogenesis cannot compensate quickly enough. Shivering, piloerection, increased muscle tone, and vasocontriction are all ways of compensating to maintain heat inside the body. As body temperature falls, so does the metabolic rate and cardiac output.
- There are several classifications of hypothermia but we will use a three-tiered system: Mild-core temperature > than 90 F (32C)-95 F (35C). Moderate- core temperature 82F(28C)-90F(32C) And Severe- core temperature <82F(28C)
- Mild Hypothermia S/S: Tachycardia, shivering, vasoconstriction, tachypnea, fatigue, impaired judgement
- Moderate Hypothermia S/S: Cold induced arrhythmias (Bradycardia/Osborne Waves), Hypotension, respiratory depression, AMS, loss of shivering
- Severe Hypothermia S/S: Coma, apnea, ventricular arrhythmias, asystole
Hyperthermia Tx:
Heat Cramps: Remove the patient from the environment (cool and shaded), administer water or electrolyte drink, if the patient is unable to drink, initiate IV fluids, consider antiemetics to assist with PO intake, patient education on potential worse outcomes. Heat Exhaustion: Remove the patient from the environment (cool, shaded, air-conditioned), place the patient in a supine position, check patient temperature, administer PO water/electrolyte drink, if patient is unable to drink, initiate IV fluids, remove patient clothing, fanning, treat for shock if indicated without warming the patient too thoroughly. Heat Stroke: Remove the patient from the environment (cool, shaded, air-conditioned), check patient temperature, initiate rapid active cooling, remove clothing, cover patient in soaked tepid sheet, fanning, avoid overcooling to prevent reflex vasoconstriction/shivering, administer oxygen as needed, IV access, IV fluid resuscitation, ECG to monitor arrhythmias, monitor body temperature throughout transport.
Drowning
Drowning can occur in any body of water, especially if you are drinking and are on vacation (about those Mai Tais). An interesting fact about drowning emergencies is that about 85 percent of drowning emergencies are male, precipitated by alcohol use. Drowning is described as respiratory impairment due to submersion or immersion in a liquid. The way a drowning occurs is that the victim's airway is submerged beneath the surface of the water. During the event of the struggle, the victim will involuntarily make a last-ditch effort to inspire oxygen, allowing water to enter the patient’s mouth, working along the posterior oropharynx, and entering the stomach. Whether the patient is conscious or unconscious at this point, the same reflexive action occurs: the mammalian dive reflex shunts blood to the heart and brain. The patient becomes apneic with PaO2 levels falling and PaCO2 levels rising, causing hypercarbia. Hypoxia eventually overrides the system and stimulates the CNS, resulting in the victim gasping for air, introducing more liquid into the oropharynx. This introduction of liquid produces reflexive laryngospasm and bronchospasm, but in turn exacerbates hypoxia, precipitating a coma. During this gasping, water enters the lungs, shunting alveolar capillary gas exchange and washing out surfactant of the lungs, deteriorating the ability of the lungs to exchange gases, causing atelectasis. If the drowning is not interrupted, hypotension, bradycardia, and hypoxia worsen and lead to cardiac arrest and death.
Drowning Tx:
Emergency treatment for drowning is straightforward; first off, remove the patient from the water! As simple as it sounds, this is a crucial step that cannot be taken if untrained personnel are not on scene. If possible, provide rescue ventilation while extricating the patient from the water. Once the patient has been extricated, position them on a flat surface and administer high-flow 100% oxygen. Evaluate ABCs and prepare for suction for possible emesis and water. Spinal motion precautions should be taken if you suspect a head or neck injury. Provide active rewarming for the patient, and establish an IV with isotonic fluids. If the patient is in hypoxic arrest, initiate CPR if the immersion has not been too extensive, and possible ACLS protocols. Do not administer abdominal thrust in your course of treatment.
Hypothermia Tx:
In this specific instance, this would be hypothermia from extended periods in water, causing the body to reduce its thermogenesis mechanisms. Whether this was from inadequate equipment or possible tides that pulled a patient out too far from shore. The management of hypothermia includes removing wet garments to reduce conduction from cold, wet clothing. Next is prevention from further heat loss by using passive or active rewarming measures, such as warm blankets, insulating materials, moisture barriers, and rescue blankets. Maintaining a supine position and avoiding rough handling of the patient to not potentiate possible cardiac arrhythmias. Warmed IV fluids may be indicated depending on the category of hypothermia. Monitoring patients' core temperature for the entirety of contact. Monitor for potential rewarming shock, which is reflex peripheral vasodilation causing a return of cold blood and acid material from extremities to the core.
Injuries on the Bottom
Diving emergencies occurring on the bottom or at the ultimate depth of the diving experience often involve nitrogen narcosis. Nitrogen or other gases build up in the blood and affect cerebral function due to the high concentration. In patients with this affliction, they appear to be intoxicated or have an altered mental status. Most often, these emergencies occur due to a diver staying at depth for too long and using too much air, or a panicked diver who has expended too much energy, increasing their oxygen consumption and their carbon dioxide production.
Injuries during Ascent
The emergencies that occur during the ascension phase of diving are serious and incredibly life-threatening. Barotrauma associated with descension injuries also contributes to ascension injuries due to the same mechanism of equilibration in the inner ear and nasopharyngeal passages. Dives that have taken place at or below 33' require staged ascension to prevent decompression sickness, also known as "the bends." These subjects divers to a rapid decrease in air pressure following exposure to compressed air (air that is used in scuba tanks). This causes a formation of nitrogen bubbles that are able to come out of the blood plasma and tissues, causing increased pressure and obstructions in smaller vessels. The bubbles tend to accumulate in joints, tendons, the spinal cord, skin, the brain, and the inner ear, causing immense pain. Serious barotrauma injuries can cause injury to the lungs from pulmonary overpressure. The sneaky thing about this affliction is that it can occur at depths of 3 feet. This can occur due to rapid ascent while the diver holds their breath, causing air to be trapped inside the lungs. As the air is trapped, the ambient pressure drops, and the trapped air expands. The air expansion causes alveolar structures to rupture and has the potential to perforate the pleura, causing a pneumothorax, subcutaneous emphysema, or pneumomediastinum. Arterial gas embolisms are also possible from pulmonary overpressure incidents.
INjuries on Descent
Most often, injuries that occur during descent in diving involve barotrauma. This is due to the increase in pressure as the diver descends into the water column. Often called "the squeeze", this is due to the equilibration between the nasopharynx and the middle ear through the eustachian tube. Divers tend to develop inner ear pain, ringing in the ears, or possible eardrum rupture due to the excessive buildup of pressure. Being able to "pop" your ears as the pressure starts to increase relieves the sensation. Divers who descend too quickly are at risk do to the reduced time of acclimation to the increasing pressure.
Injuries during Ascent cont.
Decompression sickness S/S: Classified as Type I or Type II. Type I: Joint pain, myalgias, rash, swollen/painful lymph nodes. Type II: Numbness, paresthesias, AMS, tinnitus, hearing loss, vertigo, dizziness, ataxia, nausea/vomiting, chest pain, cough, dyspnea, tachypnea, pulmonary congestion, circulatory collapse. Pulmonary Overpressure S/S: Substernal chest pain, respiratory distress, diminished breath sounds.Arterial Gas Embolism S/S: Occur within 2-10 min post ascension, rapid-sharp-tearing pain, confusion, vertigo, visual disturbances, loss of consciousness, hemiplegia, cardiac and pulmonary compromise/collapse. Pneumomediastinum S/S: Substernal chest pain, subcutaneous emphysema, irregular pulse, abnormal heart sounds, reduced blood pressure, narrow pulse pressure, alteration of voice, possible cyanosis.
Assessment of diving Emergencies
Having a thorough set of examination criteria will aid in the size-up of all diving emergencies to help differentiate between each specific problem. Gathering history is paramount to patient care.
- Time at which S/S occured
- Type of breathing apparatus
- Type of hypothermia protective garment used
- Parameters of the dive: depth, number, duration
- Aircraft travel post dive
- Rate of ascent
- Associated panic during ascent
- Diver experience
- Properly functioning equipment
- Primary medical history
- Previous dive injuries
- Medication use
- Alcohol use
The bends
Due to the possible CNS disturbance and nitrogen bubble accumulation (obstructing blood flow), the diver may need to be recompressed in a hyperbaric chamber. Check for potential pneumothorax, administer high-flow 100% oxygen, consider CPAP if no suspected pneumothorax, or intubation for an unconscious diver. Keep the patient in a supine position, and administer IV fluids. Consider possible medication administration of dexamethasone, heparin, and diazepam if there is evidence of CNS involvement. If the patient is air-lifted, fly at the lowest possible altitudes.
Nitrogen Narcosis
Nitrogen narcosis typically occurs during deep dives and extended stays at the bottom. Patients' partial pressure of nitrogen dissolves into the blood, and in extremely high concentrations, it crosses the BBB, causing altered levels of consciousness and effects similar to alcohol and narcotic use. During the dive is when this emergency can occur, altering judgment and potentiating errors. To treat this, divers are required to return to a shallow depth. To prevent this, divers must use compressed air mixed with helium to negate the effects of nitrogen.
Overpressure
- Arterial Gas Embolism: Administer high-flow 100% oxygen, consider CPAP if no suspected pneumothorax, place in supine position, IV access, consider use of corticosteroid, transport expeditiously to nearest decompression chamber.
- Pneumomediastinum: Administer high-flow 100% oxygen, evaluate for pneumothorax, IV access, and rapid transport.
- Pulmonary Overpressure: Administer high-flow 100% oxygen, decompress chest in pneumothorax, IV access, rapid transport.
Long-Term care
Hyperbaric chambers are used after emergent initial stabilization. The usage of hyperbaric chambers may be required in moderate diving emergencies and is essential in severe cases. They are used to pressurize the diver back to the original depth to allow accumulated gases to dissolve and remove them from the body's tissues (such as the bends). Once the diver is recompressed, they are gradually brought back to atmospheric pressure, allowing them to safely remove the gas naturally from the body. In cases such as AGE, this allows the bubbles to dissolve, allowing blood flow to return to the brain and or heart.
How it works
Think of a sealed soda bottle, inside there’s carbon dioxide gas (CO₂) above the liquid, under high pressure. Because of that high pressure, a lot of CO₂ dissolves in the liquid. When you open the bottle, the pressure above the liquid drops suddenly. With lower pressure, less CO₂ can stay dissolved, so it escapes as bubbles. This is applicable in decompression sickness in diving emergencies. As the diver ascends, the ambient atmospheric pressure increases, causing the dissolved gases (nitrogen) to become less soluble. During a rapid ascent, the gas can form bubbles faster than the lungs are able to expel it.
Arterial Gas Embolism
S/S: Occur within 2-10 min post ascension, rapid-sharp-tearing pain, confusion, vertigo, visual disturbances, loss of consciousness, hemiplegia, cardiac and pulmonary compromise/collapse.
Hyperbaric
At high pressure, more oxygen dissolves into plasma. In a hyperbaric chamber, this can be beneficial for decompression sickness if monitored thoroughly. But let's say I was the one operating it and I was not properly trained. Extended or high-pressure use can cause possible oxygen toxicity, causing muscle twitching, visual disturbances, seizures, nausea, vomiting, cough, chest pain, pulmonary edema, and possible barotrauma of the middle ear.
The bends
Due to the possible CNS disturbance and nitrogen bubble accumulation (obstructing blood flow), the diver may need to be recompressed in a hyperbaric chamber. Check for potential pneumothorax, administer high-flow 100% oxygen, consider CPAP if no suspected pneumothorax, or intubation for an unconscious diver. Keep the patient in a supine position, and administer IV fluids. Consider possible medication administration of dexamethasone, heparin, and diazepam if there is evidence of CNS involvement. If the patient is air-lifted, fly at the lowest possible altitudes.
Reef Diving
Cristian Danyow
Created on October 17, 2025
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Transcript
Environmental Week
Reef Diving
Diving Emergencies By Cristian Danyow
Destination:Raja Ampat
A gorgeous archipelago located in Indonesia, known for its reef diving. Tourists and locals alike routinely embark on dives ranging from 15-130'. This is the location I will be headed to for my dream vacation, to enjoy some vitamin D, salt water, and mai tais. Click on each picture for a closer look at this tropical paradise.
Environmental Emergencies
Above the surface of the water
As beautiful as this place may be, we always have to be wary of our surroundings above and below the water. Click around and see what kind of environmental factors you may encounter on the surface and potential diving emergencies that even experienced divers may suffer from
Diving emergencies
Drowning
Hypothermia
Signs and symptoms of environmental emergencies on the surface are noted in this section.
Heat related emergencies
Surface Emergency Treatments
Injuries during ascent
Injuries during descent
Signs and symptoms of environmental emergencies that occur during scuba diving are noted in this section.
Injuries at the bottom
Diving Emergency Treatments
Long-Term Care
The bends
Nitrogen narcosis
OVerpressure
Henry's Law
The amount of gas dissolved in a given volume of fluid is proportional to the prssure of gas above it.
How does it work?
Function
Equation
Scientist
+ info
Click for an example of how Henry's law works and why it is important when discussing dive emergencies.
(P_{gas}=kC), where (P) is partial pressure, (C) is gas concentration, and (k) is the constant).
William Henry, an english physician and chemist discovered it in 1803.
Recap!
Body systems
How does Henry's Law interact with the body?
Nervous system
Cardiovascular
Respiratory
We need to interact with each other. We learn collaboratively.
We are able to understand images from millions of years ago, even from other cultures.
We tell thousands and thousands of stories. ⅔ of our conversations are stories.
Could we observe these symptoms on the vacation?
Hyperbaric
The bends
Gas Embolism
Citations
Thank you!
Nervous system
As we have learned, gases dissolve based on their partial pressures, but how does that affect the nervous system? The exchange of gases is regulated by chemoreceptors in the central and peripheral areas of the body. That means that gases like carbon dioxide are continuously monitored and control our respiratory drive. As the partial pressure of carbon dioxide increases, more carbon dioxide must be expelled and more must dissolve to restore homeostasis.
Respiratory
Henry's Law governs the solubility of gases in a liquid. In the respiratory system, we breathe oxygen into the lungs, and due to the pressure gradient this forces oxygen molecules to dissolve into the plasma, where they attach to hemoglobin sites on RBCs. In reverse, carbon dioxide is removed from the system according to the pressure gradient of the gas.
Cardiovascular
The cardiovascular system is what governs the transport of gases in the body. Without the contractions of the heart, there would be no movement. The partial pressures of the gases and their solubility determine the rate at which they dissolve. In decompression sickness, the pressure has increased so dramatically that the gases cannot be dissolved into the solution and form bubbles. These bubbles in the blood can obstruct blood flow and cannot readily dissolve back into plasma for excretion.
The Surface
Imagine you are in Indonesia, a tropical environment, the sun is beating down on you, and you have forgotten your water bottle. You have a long hike down the beach, and you have been ingesting too much alcohol. You could be susceptible to a heat-related emergency such as heat cramping, heat exhaustion, and heat stroke. Even effects from cold water or prolonged durations in the water. Or so you are getting ready for a dive out in this crystal clear water, you become panicked, fatigued, or lightheaded. Such situations may result in drowning if you are not careful. Accidents on the surface are possible if you have not clearly marked off a diving zone and other boats are driving nearby.
Diving
Even some of the most experienced divers in the world can make mistakes or get complacent. There are a few classifications of diving injuries that would complicate even the best vacation. Injuries that happen during the descent phase of the dive, resulting in barotrauma, where the pressure equilibration causes damage. Injuries while at the bottom result from nitrogen narcosis of the tissue, for those of us who like to take unnecessary risks. Injuries during the ascent phase that involve barotrauma can cause a multitude of potential injuries to the diver.
Hyperthermia
Hyperthermia is a relevant piece of the equation in any tropical location. High heat, sun penetration, and humidity are all factors in a paradise such as this. Hyperthermia is defined as a state of unusually high core body temperature, either from external factors (environment) or from pyrexia (infection). The body has thermoregulation centers called thermoreceptors in the skin and mucus membranes (peripheral) and deep tissues (central) that detect changes in the body's temperature. However, these receptors are most sensitive to cold temperatures. The way the body tries to cool itself down is through two ways, diaphoresis and vasodilation, which are signs of thermolysis.
Hypothermia
Hypothermia is defined as a low core body temperature below 95°F. Think about being out in the deeper water without the proper equipment to retain any body heat; the body is stripped of its heat due to conduction. When surrounded by a cold fluid, the body's mechanisms of thermogenesis cannot compensate quickly enough. Shivering, piloerection, increased muscle tone, and vasocontriction are all ways of compensating to maintain heat inside the body. As body temperature falls, so does the metabolic rate and cardiac output.
Hyperthermia Tx:
Heat Cramps: Remove the patient from the environment (cool and shaded), administer water or electrolyte drink, if the patient is unable to drink, initiate IV fluids, consider antiemetics to assist with PO intake, patient education on potential worse outcomes. Heat Exhaustion: Remove the patient from the environment (cool, shaded, air-conditioned), place the patient in a supine position, check patient temperature, administer PO water/electrolyte drink, if patient is unable to drink, initiate IV fluids, remove patient clothing, fanning, treat for shock if indicated without warming the patient too thoroughly. Heat Stroke: Remove the patient from the environment (cool, shaded, air-conditioned), check patient temperature, initiate rapid active cooling, remove clothing, cover patient in soaked tepid sheet, fanning, avoid overcooling to prevent reflex vasoconstriction/shivering, administer oxygen as needed, IV access, IV fluid resuscitation, ECG to monitor arrhythmias, monitor body temperature throughout transport.
Drowning
Drowning can occur in any body of water, especially if you are drinking and are on vacation (about those Mai Tais). An interesting fact about drowning emergencies is that about 85 percent of drowning emergencies are male, precipitated by alcohol use. Drowning is described as respiratory impairment due to submersion or immersion in a liquid. The way a drowning occurs is that the victim's airway is submerged beneath the surface of the water. During the event of the struggle, the victim will involuntarily make a last-ditch effort to inspire oxygen, allowing water to enter the patient’s mouth, working along the posterior oropharynx, and entering the stomach. Whether the patient is conscious or unconscious at this point, the same reflexive action occurs: the mammalian dive reflex shunts blood to the heart and brain. The patient becomes apneic with PaO2 levels falling and PaCO2 levels rising, causing hypercarbia. Hypoxia eventually overrides the system and stimulates the CNS, resulting in the victim gasping for air, introducing more liquid into the oropharynx. This introduction of liquid produces reflexive laryngospasm and bronchospasm, but in turn exacerbates hypoxia, precipitating a coma. During this gasping, water enters the lungs, shunting alveolar capillary gas exchange and washing out surfactant of the lungs, deteriorating the ability of the lungs to exchange gases, causing atelectasis. If the drowning is not interrupted, hypotension, bradycardia, and hypoxia worsen and lead to cardiac arrest and death.
Drowning Tx:
Emergency treatment for drowning is straightforward; first off, remove the patient from the water! As simple as it sounds, this is a crucial step that cannot be taken if untrained personnel are not on scene. If possible, provide rescue ventilation while extricating the patient from the water. Once the patient has been extricated, position them on a flat surface and administer high-flow 100% oxygen. Evaluate ABCs and prepare for suction for possible emesis and water. Spinal motion precautions should be taken if you suspect a head or neck injury. Provide active rewarming for the patient, and establish an IV with isotonic fluids. If the patient is in hypoxic arrest, initiate CPR if the immersion has not been too extensive, and possible ACLS protocols. Do not administer abdominal thrust in your course of treatment.
Hypothermia Tx:
In this specific instance, this would be hypothermia from extended periods in water, causing the body to reduce its thermogenesis mechanisms. Whether this was from inadequate equipment or possible tides that pulled a patient out too far from shore. The management of hypothermia includes removing wet garments to reduce conduction from cold, wet clothing. Next is prevention from further heat loss by using passive or active rewarming measures, such as warm blankets, insulating materials, moisture barriers, and rescue blankets. Maintaining a supine position and avoiding rough handling of the patient to not potentiate possible cardiac arrhythmias. Warmed IV fluids may be indicated depending on the category of hypothermia. Monitoring patients' core temperature for the entirety of contact. Monitor for potential rewarming shock, which is reflex peripheral vasodilation causing a return of cold blood and acid material from extremities to the core.
Injuries on the Bottom
Diving emergencies occurring on the bottom or at the ultimate depth of the diving experience often involve nitrogen narcosis. Nitrogen or other gases build up in the blood and affect cerebral function due to the high concentration. In patients with this affliction, they appear to be intoxicated or have an altered mental status. Most often, these emergencies occur due to a diver staying at depth for too long and using too much air, or a panicked diver who has expended too much energy, increasing their oxygen consumption and their carbon dioxide production.
Injuries during Ascent
The emergencies that occur during the ascension phase of diving are serious and incredibly life-threatening. Barotrauma associated with descension injuries also contributes to ascension injuries due to the same mechanism of equilibration in the inner ear and nasopharyngeal passages. Dives that have taken place at or below 33' require staged ascension to prevent decompression sickness, also known as "the bends." These subjects divers to a rapid decrease in air pressure following exposure to compressed air (air that is used in scuba tanks). This causes a formation of nitrogen bubbles that are able to come out of the blood plasma and tissues, causing increased pressure and obstructions in smaller vessels. The bubbles tend to accumulate in joints, tendons, the spinal cord, skin, the brain, and the inner ear, causing immense pain. Serious barotrauma injuries can cause injury to the lungs from pulmonary overpressure. The sneaky thing about this affliction is that it can occur at depths of 3 feet. This can occur due to rapid ascent while the diver holds their breath, causing air to be trapped inside the lungs. As the air is trapped, the ambient pressure drops, and the trapped air expands. The air expansion causes alveolar structures to rupture and has the potential to perforate the pleura, causing a pneumothorax, subcutaneous emphysema, or pneumomediastinum. Arterial gas embolisms are also possible from pulmonary overpressure incidents.
INjuries on Descent
Most often, injuries that occur during descent in diving involve barotrauma. This is due to the increase in pressure as the diver descends into the water column. Often called "the squeeze", this is due to the equilibration between the nasopharynx and the middle ear through the eustachian tube. Divers tend to develop inner ear pain, ringing in the ears, or possible eardrum rupture due to the excessive buildup of pressure. Being able to "pop" your ears as the pressure starts to increase relieves the sensation. Divers who descend too quickly are at risk do to the reduced time of acclimation to the increasing pressure.
Injuries during Ascent cont.
Decompression sickness S/S: Classified as Type I or Type II. Type I: Joint pain, myalgias, rash, swollen/painful lymph nodes. Type II: Numbness, paresthesias, AMS, tinnitus, hearing loss, vertigo, dizziness, ataxia, nausea/vomiting, chest pain, cough, dyspnea, tachypnea, pulmonary congestion, circulatory collapse. Pulmonary Overpressure S/S: Substernal chest pain, respiratory distress, diminished breath sounds.Arterial Gas Embolism S/S: Occur within 2-10 min post ascension, rapid-sharp-tearing pain, confusion, vertigo, visual disturbances, loss of consciousness, hemiplegia, cardiac and pulmonary compromise/collapse. Pneumomediastinum S/S: Substernal chest pain, subcutaneous emphysema, irregular pulse, abnormal heart sounds, reduced blood pressure, narrow pulse pressure, alteration of voice, possible cyanosis.
Assessment of diving Emergencies
Having a thorough set of examination criteria will aid in the size-up of all diving emergencies to help differentiate between each specific problem. Gathering history is paramount to patient care.
The bends
Due to the possible CNS disturbance and nitrogen bubble accumulation (obstructing blood flow), the diver may need to be recompressed in a hyperbaric chamber. Check for potential pneumothorax, administer high-flow 100% oxygen, consider CPAP if no suspected pneumothorax, or intubation for an unconscious diver. Keep the patient in a supine position, and administer IV fluids. Consider possible medication administration of dexamethasone, heparin, and diazepam if there is evidence of CNS involvement. If the patient is air-lifted, fly at the lowest possible altitudes.
Nitrogen Narcosis
Nitrogen narcosis typically occurs during deep dives and extended stays at the bottom. Patients' partial pressure of nitrogen dissolves into the blood, and in extremely high concentrations, it crosses the BBB, causing altered levels of consciousness and effects similar to alcohol and narcotic use. During the dive is when this emergency can occur, altering judgment and potentiating errors. To treat this, divers are required to return to a shallow depth. To prevent this, divers must use compressed air mixed with helium to negate the effects of nitrogen.
Overpressure
Long-Term care
Hyperbaric chambers are used after emergent initial stabilization. The usage of hyperbaric chambers may be required in moderate diving emergencies and is essential in severe cases. They are used to pressurize the diver back to the original depth to allow accumulated gases to dissolve and remove them from the body's tissues (such as the bends). Once the diver is recompressed, they are gradually brought back to atmospheric pressure, allowing them to safely remove the gas naturally from the body. In cases such as AGE, this allows the bubbles to dissolve, allowing blood flow to return to the brain and or heart.
How it works
Think of a sealed soda bottle, inside there’s carbon dioxide gas (CO₂) above the liquid, under high pressure. Because of that high pressure, a lot of CO₂ dissolves in the liquid. When you open the bottle, the pressure above the liquid drops suddenly. With lower pressure, less CO₂ can stay dissolved, so it escapes as bubbles. This is applicable in decompression sickness in diving emergencies. As the diver ascends, the ambient atmospheric pressure increases, causing the dissolved gases (nitrogen) to become less soluble. During a rapid ascent, the gas can form bubbles faster than the lungs are able to expel it.
Arterial Gas Embolism
S/S: Occur within 2-10 min post ascension, rapid-sharp-tearing pain, confusion, vertigo, visual disturbances, loss of consciousness, hemiplegia, cardiac and pulmonary compromise/collapse.
Hyperbaric
At high pressure, more oxygen dissolves into plasma. In a hyperbaric chamber, this can be beneficial for decompression sickness if monitored thoroughly. But let's say I was the one operating it and I was not properly trained. Extended or high-pressure use can cause possible oxygen toxicity, causing muscle twitching, visual disturbances, seizures, nausea, vomiting, cough, chest pain, pulmonary edema, and possible barotrauma of the middle ear.
The bends
Due to the possible CNS disturbance and nitrogen bubble accumulation (obstructing blood flow), the diver may need to be recompressed in a hyperbaric chamber. Check for potential pneumothorax, administer high-flow 100% oxygen, consider CPAP if no suspected pneumothorax, or intubation for an unconscious diver. Keep the patient in a supine position, and administer IV fluids. Consider possible medication administration of dexamethasone, heparin, and diazepam if there is evidence of CNS involvement. If the patient is air-lifted, fly at the lowest possible altitudes.