What is Shallow Water Blackout (Drowning)?
The phrase “shallow water blackout” is often used to refer to a specific type of drowning, particularly one that follows rapid, deep breathing. This condition is also known by several other names, such as “underwater blackout,” “breath-holding blackout,” and “free-diver blackout.” It refers to a situation where someone becomes unconscious in water that is typically less than 15 feet (5 m) deep due to equipment failure or holding their breath for too long.
However, the term can be confusing, as this kind of drowning can also occur in deeper waters. Consequently, organizations like the American Red Cross, YMCA, and U.S.A. swimming have updated their jargon to describe the situation as a “hypoxic blackout.” This term refers to a situation in which a swimmer or diver, who has been holding their breath underwater after hyperventilating (breathing in and out rapidly), suddenly loses consciousness. It’s important to note that other potential causes of unconsciousness have been ruled out in these cases.
Shallow water blackouts can happen to anyone in the water, even physically fit and experienced swimmers, in any body of water, no matter how deep it is. Some people survive these events thanks to quick and efficient rescue efforts, but others are not as lucky. To prevent tragic losses, it’s essential to increase awareness around hypoxic blackouts and the importance of safety while swimming or diving.
What Causes Shallow Water Blackout (Drowning)?
Hypoxic blackouts, which are fainting episodes caused by a lack of oxygen, usually come from a combination of factors. These may include a lack of awareness of one’s surroundings, not taking the necessary safety precautions, and improper practices. The average person can hold their breath for about 30 to 90 seconds. It’s extremely uncommon for people to hold their breath much longer than this without special training or being well-prepared.
Hypoxic events mainly happen when individuals try to hold their breath for an extended period, going beyond what is safe for them. This is particularly dangerous if they don’t take proper breaks between these extended sessions of breath-holding. Even highly trained individuals who can hold their breath underwater for over 6 minutes are still at risk of drowning. In fact, drowning often happens to healthy and symptom-free swimmers during their breath-holding training, competitive races, and long periods of underwater swimming and diving.
The people most likely to experience hypoxic blackouts are beginner divers going to moderate depths.
Furthermore, hypoxic blackouts are often directly related to behaviors such as hyperventilation, which is taking a series of quick breaths before going underwater. This is the main cause of drowning among expert swimmers. In public swimming areas, if lifeguards aren’t aware of potentially dangerous behaviors such as intentional hyperventilation, it significantly increases the risk of dangerous situations occurring.
Risk Factors and Frequency for Shallow Water Blackout (Drowning)
Each year in the United States, there are approximately 4000 cases of fatal drownings. However, the country has made significant progress in reducing this rate by over 300% in the last forty years. For instance, in 1970, there were 3.87 drowning deaths per 100,000 people, but by 2000, this rate had gone down to 1.24 per 100,000. This reduction can be credited to advances in understanding and treating drowning incidents.
Despite this progress, a number of fatalities still occur that could potentially be prevented with moderate effort. Drowning remains the fifth leading cause of accidental deaths in the United States.
Interestingly, there’s one type of incident that hasn’t seen a decline in fatalities: drownings related to prolonged breath-holding after hyperventilation, also known as shallow water blackouts. These incidents tend to involve males under 40 and have a high rate of fatalities.
- In a case study by the CDC, 13 out of 16 reported dangerous breath-holding incidents in New York involved males.
- Out of the 16 cases, 4 resulted in fatalities, with 3 of those associated with military personnel.
- Between 2008 and 2015, the Marine Corps reported a total of 24 drownings, with 3 happening during duty.
- During the same period, the Navy reported 46 total drownings, with 14 occurring while on duty.
Signs and Symptoms of Shallow Water Blackout (Drowning)
When a person is found unconscious in water, fast action is necessary. The individual needs to be promptly removed from the water and brought to a safe area on land or in a boat. Immediately after the person’s airway can be opened and the rescuer is out of harm’s way, mouth-to-mouth ventilation should start. This is important because starting rescue breathing as quickly as possible greatly improves the chance of the person surviving.
After these initial rescue efforts are underway, make sure to call emergency medical services (EMS) straight away. The patient will then need to be taken to the nearest medical facility the moment they stabilize. If there’s other people around, have them look for any available medical equipment. At the same time, if it’s possible, quickly ask any witnesses (like friends, family, lifeguards or swimming instructors) for a brief summary of what happened. Gathering this information while physically assessing the patient can be extremely helpful for making decisions about diagnosis and treatment. More details can be obtained if the patient stabilizes further.
The physical exam will also be quick. After the person is out of the water, start to evaluate their level of consciousness, and check their circulation, airway, and breathing. This is also known as the BLS/ACLS protocol (basic life support/advanced cardiac life support). This should be done while resuscitation efforts are ongoing.
Testing for Shallow Water Blackout (Drowning)
If there’s an emergency related to water, like drowning, there won’t be enough time for detailed checks or tests. Instead, the focus should be immediately on starting life-saving actions.
Treatment Options for Shallow Water Blackout (Drowning)
If someone isn’t responding and appears to be having problems breathing or isn’t breathing at all, the first things to do are to check their responsiveness and start giving ‘rescue breaths’ – this means breathing into their mouth to help them breathe. Then, check if the person has a pulse. If they do, you should adjust their airway using a ‘jaw thrust’ or ’tilt-chin’ maneuver (if they have a head injury). These actions involve moving their jaw or tilting their chin to help clear their airway, making breathing easier. If they’re still not breathing by themselves, you should give them around ten breaths per minute. It’s also important to keep checking their pulse every two minutes.
If the person doesn’t have a pulse, start performing CPR. This involves giving 30 chest compressions, to help circulate blood, followed by two more rescue breaths, and repeating this cycle five times, over approximately two minutes. If possible, try to get advanced life support involved as soon as possible, which could involve using an automated device (an automated external defibrillator or AED) to shock the person’s heart back into a normal rhythm.
Regurgitation, or throwing up, often happens when trying to resuscitate someone who has drowned. Because of the risk of this, avoid doing things like stomach thrusts or tilting their head down to clear water from their airway, as it can delay ventilation – or getting air into their lungs – and increase the risk of death. Anyone who has been rescued from the water and lost consciousness, even briefly, should be checked at a hospital. People who’ve needed resuscitating will probably need to be closely observed in the intensive care unit (ICU) of a hospital and may possibly need a machine to help them breathe.
What else can Shallow Water Blackout (Drowning) be?
When a swimmer suddenly loses consciousness in the water, there could be several reasons for it. It’s important for medical professionals to take into account all possible causes in order to provide the most appropriate help. One of the top causes of accidents in the water is hypoxic blackout, where the person passes out due to lack of oxygen. But other factors could also be at play, including heart diseases like coronary artery disease or cardiomyopathy, irregular heart rhythms, and epilepsy.
All these conditions can become more severe when there is a lack of oxygen, like in a situation where someone is under water. There are other things that could increase the risk of losing consciousness underwater too. For example, if someone has a condition called prolonged QT, which could be caused by certain medicines, metabolic disturbances like low potassium levels (hypokalemia), or even alcohol.
Knowing what to look for can be very helpful in a rescue situation. Here are some things that might be indicators:
- If it’s related to the heart, the swimmer might suddenly stop swimming on the surface and display strange, short-lived behaviors.
- If it’s a hypoxic blackout, the swimmer may be seen breathing heavily before going underwater and then not coming back up.
Being aware of these different signs can improve the success rate of rescue efforts.
What to expect with Shallow Water Blackout (Drowning)
A hypoxic blackout, which is when the brain doesn’t get enough oxygen, can have different outcomes based on several factors. The outcome is mainly affected by how long the patient goes without oxygen – the longer the time, the worse the outcome.
Other important factors that can influence the outcome include the patient’s general health and fitness level before the blackout, as well as the quality and timeliness of the rescue efforts. The last part depends on the abilities of those who are conducting the resuscitation, the type of medical supplies available, and how close a medical facility is for additional treatment after initial resuscitation. Due to these varying factors, it is hard to predict exactly how well someone will recover after a hypoxic blackout.
If the patient receives rapid and effective resuscitation and prompt medical attention, and the period of oxygen deprivation is short, they generally do well. If a patient arrives at the hospital and can breathe and have a heartbeat on their own, they usually recover successfully. However, if any of these conditions are not met, the outcome can be fatal or result in long-term brain damage.
This is backed by a statistic stating that in 95% of cases where a person nearly drowns but regains consciousness due to successful CPR, they were able to go home without any adverse effects or lasting problems.
Possible Complications When Diagnosed with Shallow Water Blackout (Drowning)
After a near drowning incident, people usually have to be monitored for four main health issues.
Breathing problems are the most common complication after a near drowning event. These patients generally need to be connected to a breathing machine for around two days. This time allows the body to regenerate an important substance called surfactant that keeps the lungs functioning properly. Surfactant can be damaged or washed out by any water that may have entered the lungs. Any attempts to remove the breathing machine earlier than two days might increase the risk of a condition known as pulmonary edema, which requires reinserting the breathing tube.
A lung infection like pneumonia isn’t usually caused by water that’s entered the lungs during a near drowning incident, because the water in swimming pools, rivers, and beaches usually doesn’t contain enough bacteria to cause pneumonia in the first 48 – 72 hours after the incident. Despite the presence of water in the lungs, lung infections aren’t typically seen immediately after a near-drowning. Instead, pneumonia is often associated with stomach contents that have been inhaled during the CPR efforts, and at this point, antibiotics should be started.
A condition where your lungs hold too much fluid, known as pulmonary edema, should improve within 3 – 4 days after a near drowning. If fluid continues to build in the lungs beyond this period, especially if the person also has a fever, it may be a sign of developing pneumonia. If the person was in contaminated water, it’s reasonable to start antibiotics sooner.
Sometimes the heart can also be affected after a near-drowning. There can be a decrease in the heart’s ability to pump blood, which can lead to low blood pressure. If fluids and warming the body don’t stabilize the blood pressure, blood pressure medication may be required and a heart ultrasound can be done to help guide further treatment.
Prolonged lack of oxygen can affect the brain, possibly causing long-lasting damage. It’s crucial to ensure good oxygen supply during and after CPR. Regular checks on a patient’s neurological function are recommended.
Lastly, a condition known as metabolic acidosis occurs in about 70% of the hospital patients after a near-drowning situation. This condition, caused by a lack of oxygen, can lead to acute kidney injury and other organs not working properly. To treat this, appropriate ventilator support is necessary and a substance called bicarbonate can be given if the acid levels become very high.
Common Concerns:
- Breathing problems
- Potential lung infections (Pneumonia)
- Fluid buildup in the lungs (Pulmonary edema)
- Heart complications
- Nervous system damage from loss of oxygen
- Metabolic acidosis
Preventing Shallow Water Blackout (Drowning)
The best way to lower the number of drowning incidents is by preventing them. It’s estimated that 80 to 90% of all drowning cases could have been avoided. One common myth is that hyperventilating before diving can help improve breath-holding abilities, but this is not true. This incorrect information needs to be corrected by diving instructors and doctors to ensure people understand that hyperventilation actually reduces breath-holding capability and safety. The American Red Cross, U.S.A. Swimming and the YMCA have taken important steps to raise awareness of the risks associated with hyperventilating before submerging underwater.
At public swimming pools or other places with lifeguards, it’s essential for the lifeguards to quickly recognize and respond to dangerous situations like hyperventilation. When lifeguards are alert and attentive, they can greatly decrease the risk of drowning. However, simply having a lifeguard present isn’t enough if they’re not actively watching the water. This can give swimmers a false sense of security and lead to tragic accidents. Factors like the clarity of the water, proper pH levels, and reducing hazards are important for maintaining safety in swimming locations.
In public sites, easy access to rescue equipment, continuous surveillance by lifeguards, and having a phone nearby are recommended. The goal is to prevent situations where a rescue might be necessary. If a swimmer does need rescuing, it’s crucial to retrieve them from the water quickly, as this can greatly increase survival chances following resuscitation.
