Drowning Cardiac Arrest

What Is Drowning?

The respiratory impairment experienced as a result of water immersion is called drowning. Though a preventable cause of death, drowning is responsible for more than three lakh deaths worldwide in a year. Non-fatal drowning is more frequent than fatal ones. Drowning results in cardiac and respiratory arrest and may also result in pulmonary, neurological, cardiovascular, and other injuries.

The following are some of the terms associated with drowning:

• Fatal Drowning: Drowning results in death (fatal outcome).

• Non-fatal Drowning: In non-fatal drowning, the affected survives as respiratory impairment is halted before death. Based on the severity, it is further classified as a mild, moderate, or severe impairment.

• Rescue: Rescue is an intervention to stop the progression of drowning but results in respiratory symptoms in no time.

What Are the Risk Factors of Drowning?

The factors which increase the risk of drowning are:

• Inappropriate adult supervision.

• Overestimation of swimming ability.

• Scuba diving.

• Poor judgment.

• Depression.

• Behavioral disorders in children.

• Risk-taking behavior.

• Natural disaster.

• Alcohol.

• Hyperventilation before shallow diving.

• Seizure disorder increases the risk of fatal drowning.

What Is the Pathophysiology?

Drowning starts with a period of panic followed by abnormal breathing patterns, holding of breath, air hunger, and the struggle to breathe. The inspiratory reflex results in water aspiration, coughing, hypoxemia (low blood oxygen level), unconsciousness, and apnea (temporary breathing cessation).

Hypoxemia leads to cardiac arrest and affects other organ systems. Differences in fluid composition may also affect the patient’s course and treatment. The temperature of the water, presence of contaminants, and tonicity affect the clinical sequelae. Cardiac arrest that occurs due to saltwater drowning has a poorer prognosis. The increased amount of pathogens and contaminants in the water increases the risk of infection and can lead to sepsis. Immersion in cold water can lead to ventricular dysrhythmia.

What Are the Organ-Specific Signs and Symptoms?

The organ-specific signs and symptoms that occur due to drowning are:

• Pulmonary Signs and Symptoms:

Fluid aspiration leads to lung injury of varying levels. The water results in disruption of the alveolar-capillary membrane, increasing its permeability. This leads to non-cardiogenic pulmonary edema and ARDS (Acute Respiratory Distress Syndrome). Poor lung compliance leads to hypoxemia and intrapulmonary shunting.

• Neurologic Signs and Symptoms:

Non-fatal drowning victims may suffer neurological symptoms due to hypoxemia and hypoperfusion due to cardiac arrest. The symptoms may be mild or can even result in the comatose stage. The development of cerebral edema worsens the condition.

• Cardiovascular Signs and Symptoms:

Cardiovascular signs and symptoms occur due to hypothermia and hypoxia. Abnormal heart rhythms (dysrhythmias) occur and may present as atrial fibrillation, sinus bradycardia, sinus tachycardia, pulseless electrical activity, and asystole.

• Other symptoms:

Other symptoms include respiratory acidosis, multiorgan dysfunction syndrome in severe cases, renal failure in rare cases, hemolysis, and coagulopathy.

What Are the Bystander Interventions and Hospital Care Done in Drowning Victims With Cardiac Arrest?

Rescue measures and immediate resuscitation done by bystanders or medical personnel improve the prognosis of the victims. Especially in the case of patients with cardiac arrest due to drowning, the outcome gets improved with CPR (Cardio Pulmonary Resuscitation) than in cases of non-CPR. Conventional CPR with rescue breaths is preferred over compression-only CPR.

The following are the steps to be taken:

• Rescue Breathing:

Begin conventional CPR with rescue breaths immediately. Ventilation is the most important treatment for drowning cardiac arrest victims. Rescue breaths are extremely important in such cases; if the rescuer is unwilling to rescue breath, then compression-only CPR should be done.

In hypothermic patients with cardiac arrest, resuscitation is continued until the victim's core temperature reaches 32 to 35 degrees Celsius. Suppose the return of spontaneous circulation (ROSC) does not take place in 30 minutes, even after initiation of advanced life support. In that case, the victim is at high risk for a poor neurologic outcome. Prolonged resuscitations are more effective for drowning that happens in cold water.

• Extracorporeal Cardiopulmonary Resuscitation:

Extracorporeal Cardiopulmonary Resuscitation is done in cases where conventional CPR fails. In victims with mixed hypothermic and hypoxic cardiac arrest and undergoing Extracorporeal Cardiopulmonary Resuscitation, neurologically intact survival is seen in 5 to 20 percent of cases. The outcome is better in patients with normal potassium levels and core temperatures below 26 degrees.

• Pulse Examination:

A pulse examination is usually done before starting rescue breaths.

• Chest Compressions:

Chest compression should be initiated once the victim is out of the water and may even be done on the boat. High-quality chest compressions should be done.

• Automated External Defibrillator (AED) administration:

If defibrillation is needed, shock is delivered with AED. Before administering AED, the victim's wet clothes should be removed, and the chest area should be made dry.

• Cervical Spine Immobilization:

Cervical Spine Immobilization is done only in cases with a history of trauma (example diving in shallow water).

• Tracheal Intubation:

Early tracheal intubation is started. An orogastric tube is used for relieving gastric distension.

• Correction of Altered Mental Status:

Drowning victims who have consistently altered mental status that is comatose patients are managed in the following way:

• The head of the bed is elevated to 30 degrees, except in hypotensive patients.

• A comatose drowning individual should take an electroencephalogram (EEG) to rule out status epilepticus.

• Seizure activity should be controlled, and non-sedating anticonvulsants are preferred.

• Maintain euglycemia.

• Diuretics are used to prevent hypervolemia.

• If delayed cerebral edema develops, then the prognosis gets worsens.

Antibiotics:

Prophylactic antibiotics are given in cases where the drowning water is heavily contaminated.

Keeping Warm:

Steps should be taken to reduce the victim’s core temperature to less than 33 degrees Celsius.

Post-Arrest Management:

Targeted Temperature Management (TTM) is done for all drowning cardiac arrest patients, a core temperature of 33 to 36 degree Celsius should be maintained for a day. Most victims must have acquired this temperature due to environmental exposure and mixing peripheral blood with core blood.

What Are the Initial Testing Procedures?

The following evaluations are done:

• Core temperature measurement.

• Chest radiograph.

• Pulse oximetry saturation.

• Liver function test, blood count, and prothrombin time.

• Electrocardiogram.

• Serum ethanol concentration in case of alcohol use.

• Evaluation of injuries.

• Brain CT (Computed Tomography) in case of altered mental status.

Conclusion

Drowning starts with a panic period followed by abnormal breathing. The inspiratory reflex that follows leads to hypoxemia which may lead to cardiac arrest. In the case of patients with cardiac arrest due to drowning, the outcome gets improved with CPR. Conventional CPR with rescue breaths is preferred over compression-only CPR in case of drowning cardiac arrest victims.