Chapter 14: Drowning and Scuba-Related Emergencies

Drowning

Drowning is a form of suffocation caused by immersion in water or other liquid. Drowning begins as a person gasps for air, either while struggling to stay afloat or underwater once the patient can no longer hold his or her breath.

As some water is inhaled, it can stimulate laryngospasm and the closing of the vocal cords.  This is the body’s natural response to prevent water from entering the lungs, but it also prevents the inspiration of air. As suffocation continues, hypoxia worsens. The patient will become unresponsive and die. Laryngospasm may relax after unresponsiveness, and it will always cease with death (if not before). If the patient is face down, the lungs may remain dry and the patient may float. If the patient is face up, water can passively fill the lungs and the patient will sink.

Assisting a Responsive Drowning Patient

A responsive drowning patient will be struggling in the water. Submersion below the surface will occur repeatedly, and vocalization will be minimal to non-existent. Other signs that indicate a drowning patient include:

  • The patient is not using his or her legs to move forward and tread water.
  • The patient is vertical in the water, usually trying to rise out of the water to breathe rather than trying to swim forward.
  • The patient has limited forward motion, usually struggling for only 20 to 60 seconds before submerging.
  • The patient has an expression of fear.
  • The patient will usually be flailing his or her arms at the sides, alternately moving up and pressing down.

Assisting Responsive Drowning Patients. Water rescues should be performed by individuals who have been specifically trained for such situations. Additionally, all responders in and around water should be wearing life jackets/PFDs if they are available.

A responsive drowning patient is in the rapid transport category. Perform a scene assessment. If the scene is safe to enter, or if you are equipped to safely enter the scene, rescue the patient from land by following this order of steps to ensure your own safety:

  1. Talk Assist: Instruct and encourage the patient to perform a self-rescue.
  2. Throw Assist: Throw a rope or buoyant object, with or without an attached line, to the patient.
  3. Reach Assist: Reach out to the patient with a rigid object (e.g., a ladder, paddle, tree branch, rescue tube, water noodle).

You must always remember not to endanger yourself. Rescues that involve entering the water and swimming to the patient require special training, (e.g., Lifeguard training). Do not enter the water and swim to a drowning patient without this training; you are not likely to save the person, and you will be putting your life danger in addition to the patient’s life. Likewise, leaping into water, even shallow water, to help someone may seem courageous, but choosing a less dramatic method is safer and usually more effective. You can help a person only if you maintain your personal safety and stay in control of the situation. The talking (instructing), throwing, and reaching methods presented here help you do both.

Talk Assist. If the patient has some swimming ability, instruct and encourage the patient to swim for safety if the distance is appropriate for the patient’s swimming skills and energy level, and the conditions of the water.

If the person has limited or no swimming skills, or if he or she is unable to swim normally due to exhaustion, injury, or cold exposure, encourage the patient to tread water or float on his or her back. Treading water to stay at the surface takes more energy than floating (but less energy than swimming).

Motionless floating is useful for conserving energy. This is an effective survival skill in calm, warm water, but may be very difficult in cold water.

Throw Assist. Throw an object that the patient can grab to stay afloat, such as a PFD/lifejacket or ring buoy. If a line is attached, you can pull the patient to safety.

Reach Assist. A reaching assist may be used if a throwing assist is unavailable or the circumstances make throwing an object ineffective. Extend your reach with any object that will reach the patient, such as a pole, oar, tree branch, shirt, belt, towel, or rescue tube. If there are no objects available to extend your reach, try to extend your arm and grasp the patient, or extend your leg so that the patient can grab onto your foot. As always, protecting yourself is your top priority: Always ensure that you are in a stable position and are not at risk of being pulled into the water yourself. If possible, lie down on a pool deck, dock, or pier.

Once the Patient is Rescued

If you suspect that the patient may have a head and/or spinal injury, you must support his or her head and neck, keeping it aligned with the body, before pulling the patient from the water. It may be necessary to turn the patient onto his or her back; if so, the patient’s head, neck, chest, and body must be aligned, supported, and turned as one unit. The patient should be floated, on his or her back, onto a firm support, such as a backboard, before being removed from the water.

Once the patient is out of the water, perform a primary assessment and provide care for any conditions found. The patient should be placed in the rapid transport category. All survivors of drowning incidents must be assessed by a physician immediately, regardless of how rapid the recovery may seem.

You should attempt to resuscitate the patient even if he or she has been submerged for a prolonged period. Patients have been successfully resuscitated even after being submerged in cold water for longer than 30 minutes.

Self-Rescue

If you unexpectedly fall into the water without a PFD/lifejacket, you may need to remove clothing in order to swim or float; however, some clothing, such as a long-sleeved shirt that buttons, will actually help you float and protect you from cold. If your shoes are light enough for you to swim in comfortably, leave them on. If they are too heavy, remove them.

Tread water to stay in an upright position while you signal for help or wait for rescue. To tread water, stay vertical, move your hands back and forth, and use a kick that you can do effectively and comfortably, using the least amount of energy.

If you are wearing a PFD/lifejacket, you should await rescue and adopt the Heat Escape Lessening Position (HELP) (figure below):

  1. Press your arms against your armpits.
  2. Squeeze your thighs together and adjust the bend of your hips and knees as needed to keep stable in the water.
  3. Place your forearms across your chest or use your hands to pull your knees towards your chest.

Unresponsive Drowning Patient.

Rescuing an unresponsive drowning patient requires specific training and is out of this course’s scope of practice. Australia’s courses for white-water guides are the Swiftwater Rescue Technician (SRT) courses. For Surf Lifesaving, training begins with the Bronze Medallion course.

Cold-Water Immersion and Drowning

Hypothermia caused by cold-water immersion occurs faster than hypothermia caused by cold air exposure; however, diagnosis and treatment remain the same, regardless of the cause.

It is important to understand the four phases of cold-water immersion:

  1. Cold Shock Response: A rapid cooling of the skin, causing the patient to gasp, followed by hyperventilation. This can last for 1 to 2 minutes.
  2. Cold Incapacitation: A further cooling of deeper nerve and muscle fibres, which causes loss of coordination and weakness, leading to incapacitation within approximately 15 minutes.
  3. Hypothermia: Requires 30 minutes or more for an appropriately dressed adult to become mildly hypothermic.
  4. Circum-rescue Collapse: Can occur just prior to, during, or after a rescue. Symptoms range from syncope to cardiac arrest.

Most deaths in cold-water result from the Cold Shock Response (i.e., when the head is underwater) or drowning due to Cold Incapacitation. Normally, a personal flotation device (PFD) must be worn to remain afloat long enough for a person to die from hypothermia.

Cold-Water Rescue

Self-Rescue. Should you find yourself in cold open water and at risk of cold-water immersion, attempt to rescue yourself by climbing out of the water and into a boat, raft, or other mode of marine transportation, if available.

If you have fallen through the ice, place your arms on the surface of the ice and control your breathing by taking some slow deep breaths. Kick your legs until your body is horizontal to the water’s surface, and then kick and pull forward until you are on top of the ice. Roll or crawl a safe distance away from the hole before standing up.

Surviving to Await Rescue. If self-rescue is not possible in cold open water, you may be able to increase your survival time by climbing out of the water as much as possible onto a capsized boat or other floating object. If you are wearing a PFD/lifejacket and there is nothing to climb up on, you may adopt the HELP position.

If several people are together, adopt the Huddle position (figure below):

  1. Face each other.
  2. Have each person squeeze his or her thighs together.
  3. Form a circle and hug each other. Each person should place one arm above and one arm below the arms of those adjacent and pull the sides of their chests together.
  4. Sandwich any children or people without PFDs inside the Huddle.

The Huddle position is most effective for groups of three to five.

If you have fallen through ice and you are unable to climb out of the water on your own, stop struggling. Place your arms onto the ice and allow them to freeze in place; this will prevent drowning if moderate hypothermia causes incapacitation or unresponsiveness.

Cold-Water Drowning

If a patient has drowned in cold water, he or she is in the rapid transport category. If the scene is safe to enter, perform the steps for rescuing an unresponsive drowning patient.

Depending on the situation, there may or may not be a chance of successfully resuscitating the patient. The relevant factors are the temperature of the water and the length of the time the patient was underwater (submersion time), if known. Colder water reduces the rate at which brain cells die when they become hypoxic, so drowning in colder water can increase a patient’s chances of resuscitation.

You should attempt resuscitation in either of the following situations:

  • The water temperature is less than 6°C and the known submersion time is less than 90 minutes.
  • The water temperature is 6 to 10°C and the known submersion time is less than 30 minutes.

Once you begin CPR, you should continue for 25 minutes. If the patient shows no signs of improvement after this period, or if your safety is threatened, you may cease CPR.

Scuba-Related Illness

Physiology

The human body is always under pressure as a result of the weight of the atmosphere pressing  in and down on it. The standard level of pressure at sea level is referred to as one atmosphere (1 ATM). Pressure increases dramatically underwater because of the weight of the water itself. Descending to a depth of just 10 metres  (33 feet) results in pressure two times higher than at sea level (2 ATM). At a depth of 50 metres  (165 feet), the pressure is 6 ATM, or 6 times higher than at the surface.

Divers Alert Network

The Divers Alert Network (DAN) is a network of recreational divers. Membership is required. DAN’s mission is to provide emergency medical assistance to divers and to support diving safety. DAN has a diving medicine physician who is oncall 24/7 to help with diagnosis and treatment of suspected SCUBA-related illnesses. The DAN hotline number is 1-919-684-9111. If you have a membership available, contacting DAN can provide valuable information for assessment and treatment of a patient with a known or suspected diving injury.

Barotrauma of Descent

Normally, gas-filled spaces are in equilibrium with the pressure of the outside environment. For example, air in the middle ear remains equalized in pressure with the atmosphere via the Eustachian tube (which runs from the middle ear to the pharynx). Similarly, equalization occurs in the sinuses through connections to the nasal cavity, and this even occurs in a dive mask.

Barotrauma of descent results when something blocks the opening between the internal space and the environment, trapping gas within the space. As the diver descends and the external pressure increases, there is a relative decrease, or negative, pressure within the blocked space, causing pain and other symptoms, such as tympanic membrane rupture (middle ear); congestion, edema and hematoma (sinuses); and capillary rupture and edema in and  around the eyes (mask).

Barotrauma of Ascent

As the pressure decreases during a diver’s ascent, gas in body spaces will expand. Normally this gas will escape, maintaining equilibrium with the external environment. However, if this venting is prevented due to obstruction, the expanding gases will distort the tissues within the body space and cause tissue damage and bleeding. This typically occurs in teeth and also in the gut (in those who swallow air or chew gum while diving). These patients typically present with local pain on ascent.

Some patients experience a more severe disorder called pulmonary barotrauma. This occurs when a diver ascends while holding his or her breath (breath holding). As external pressure decreases during ascent, the trapped air in the lungs expands against the closed glottis, causing the alveoli to rupture. Signs and symptoms include local capillary bleeding, pneumomediastinum, arterial gas embolism (AGE), chest pain, cough, and even froth in the mouth.

Arterial Gas Embolism (AGE). As depth increases, air is compressed, but this process will reverse on ascent. If the compressed air in a diver’s lungs cannot freely escape during an ascent (particularly a rapid one), then rapid gas expansion within the lung may rupture lung tissue. Air entering the arterial blood through ruptured pulmonary vessels can distribute bubbles into body tissues (including the heart and brain), where they disrupt circulation. This is referred to as an arterial gas embolism (AGE). An AGE may cause minimal neurologic symptoms, dramatic symptoms requiring medical attention, or death.

Common signs and symptoms of AGE include:

  • Headaches.
  • Seizures.
  • Unresponsiveness.
  • Confusion.
  • Visual disturbances.
  • Bloody froth from the airway (rare).
  • Paralysis or weakness.

Treatment of AGE includes the following: provide supplemental high-concentration oxygen and ensure rapid transportation to a medical facility (preferably one capable of dealing with diving injuries). The patient should remain in a supine position. If air transportation is used, the pilot should fly at an altitude of 305 metres (1,000 feet) or less, or use an aircraft that can be pressurized  to 1 ATM.

The best prevention for AGE is avoiding ascent with a closed glottis and remembering to exhale bubbles. In general, it should be assumed that a diver has suffered from AGE when he or she is unresponsive upon surfacing or loses responsiveness within 10 minutes after surfacing.

Decompression Sickness (DCS). Breathing air under pressure causes excess inert gas (nitrogen) to dissolve in the blood and body tissues. The amount dissolved is proportional to, and increases with, depth and time. As the diver ascends to the surface, the excess dissolved nitrogen comes out of solution. If the return to the surface is slow and controlled, the nitrogen is released from the blood through the alveoli and exhaled. If the ascent is too rapid, some of the gas can supersaturate within the tissues, coming out of solution to form bubbles in the surrounding tissues. This condition is known as decompression sickness. It is sometimes referred to as the bends. Symptoms of DCS typically occur 15 minutes to 24 hours after ascent.

Signs and symptoms can include any of the following, depending on where in the body nitrogen bubbles appear:

  • Itchiness, swelling
  • Blotchy, mottled, or marbled skin rash
  • Severe joint pain
  • Fatigue or dizziness
  • Personality changes
  • Chest pain, cough, shortness of breath
  • Numbness or tingling
  • Weakness or paralysis
  • Loss of bowel or bladder function
  • Shock
  • Unresponsiveness

Treatment of DCS mirrors the treatment for AGE and involves providing supplemental high concentration oxygen and rapid transportation to a medical facility (preferably one capable of dealing with diving injuries). The patient should remain in a supine position. If air transportation is used, the pilot should fly at an altitude less than 305 metres (1,000 feet) or use an aircraft that can be pressurized to 1 ATM.

Nitrogen Narcosis. Nitrogen narcosis is caused when the dissolved nitrogen in the body increases to the point that it begins to impair the nervous system. This can alter a diver’s thought processes and decrease his or her ability to make judgments and calculations. It can also decrease motor skills, worsening performance in tasks requiring manual dexterity. Pressure increases with depth, and so does the severity of the narcosis. The effects vary widely from individual to individual, and even from day to day for the same diver.

Nitrogen narcosis can have any of the following signs or symptoms:

  • Euphoria
  • Lightheadedness
  • Impaired judgment
  • Confusion
  • Hallucinations
  • Delayed response to signals, instructions,  and other stimuli
  • Hysteria

Because of the perception-altering effects of narcosis, a diver may not be aware of the changes in his or her mental state. The best prevention for nitrogen narcosis is vigilant monitoring of diving partners and helping a diver ascend safely if he or she shows any of the signs or symptoms. Some symptoms may become resolved with ascent to shallower depths (usually less than 20 metres or  65 feet).