Submersion injury case file

Submersion injury case file

Eugene C. Toy, MD, Barry C. Simon, MD, Terrence H. Liu, MD, MHP, Katrin Y. Takenaka, MD, Adam J. Rosh, MD, MS

Case 43

A group of teenagers was swimming at the lake, when one of the boys failed to surface after diving off a platform. He was quickly found and rescued by another swimmer from the lake bottom. The patient was noted to be apneic, and cardiopulmonary resuscitation (CPR) was initiated by one of the bystanders. After the paramedics arrived, the patient was noted to have spontaneous shallow respirations, a weak palpable pulse, and Glasgow coma scale (GCS) score of 7 (eyes 1, verbal 2, motor 4). The paramedics intubated the patient and transported him to the emergency department (ED). In the ED, the patient has an initial pulse of 70 beats per minute, blood pressure of 110/70 mm Hg, temperature of 35.6°C (96.1°F), GCS score of 6 (eyes 1, verbal 1, motor 4), and oxygen saturation of 92% on 100% FiO2.

⯈ What are the complications associated with this condition?

⯈ What is the best treatment for this patient?

ANSWER TO CASE: 43

Submersion Injury

Summary: A teenage boy presents with near-drowning following a diving accident at a lake.

• Complications: Submersion injury results in global hypoxia and tissue ischemia primarily affecting the brain, lungs, and heart. Early complications include noncardiogenic pulmonary edema, hypoxic encephalopathy, respiratory and metabolic acidosis, dysrhythmias, and renal impairment. Coagulopathy, electrolyte abnormalities, and hemodilution or hemoconcentration are rare but possible sequela. Pneumonia and acute respiratory distress syndrome can occur later in the patient’s hospital course.
• Best treatment: The most important treatment to optimize outcome is rapid initiation of resuscitation in the prehospital setting (ie, stabilizing the ABCs). To this end, bystander CPR can be vitally important. Victims of submersion injury often require aggressive respiratory support, which may range from administration of supplemental oxygen to intubation. If cervical spine injury is suspected (as in this patient who dove off a platform), cervical spine stabilization should be maintained until spinal trauma is ruled out.

ANALYSIS

Objectives

1. Learn the pathophysiology of submersion injury.
2. Become familiar with the epidemiology and prevention of drowning.
3. Learn the special problems associated with cold-water-submersion injury.

Considerations

The initial management of patients with submersion injury is stabilization of the ABCs and correction of hypoxemia. In the ED, all of these patients require continuous cardiac monitoring and pulse oximetry. Initial diagnostics may include a complete blood count, blood glucose, electrolytes, creatinine, arterial blood gas, and chest x-ray. This patient will need to be admitted to the ICU where continued cardiopulmonary monitoring and mechanical ventilation support can be provided.

When encountering a patient with a submersion injury, the ED physician must always consider whether any precipitants exist that also require treatment. These precipitants may include alcohol or drug intoxication, seizures, hypoglycemia, cardiac arrest, attempted suicide or homicide, and child abuse or neglect. In addition, if the submersion is associated with a history of trauma (eg, diving into water, motor vehicle collision), cervical spine and head injuries are considerations. Hypothermia should also be considered if the patient is submersed in cold water. After the patient is hemodynamically stable, radiographic imaging of the cervical spine (plain x-rays or computed tomography [CT]) and CT of the head may be necessary to rule out concomitant injury.

Approach To:

Submersion Injury

DEFINITIONS

DROWNING: Death following a submersion event.

SUBMERSION VICTIM: Patient with some degree of submersion distress requiring medical evaluation and treatment.

IMMERSION SYNDROME: Syncope or sudden death that occurs after submersion in water that is at least 5°C less than body temperature. Due to dysrhythmias induced by vagal stimulation.

CLINICAL APPROACH

Epidemiology and Prevention

Drowning is the fourth most common cause of accidental death in the United States. In children 1 to 14 years old, it is the second leading cause of death (behind motor vehicle collisions). Risk factors for drowning include age, gender, and race. The incidence of submersion injuries peaks in toddlers and young children, adolescents and young adults, and in the elderly. However, drowning deaths are most common in toddlers and older teenagers. Males account for 80% of drowning victims older than 12 months. Between 15 to 19 years of age, black boys have drowning rates 12 to 15 times higher than those of white boys.

Alcohol use and other medical conditions have also been associated with an increased risk of submersion injuries. Among teenagers and adults, alcohol use may be a contributing factor in 30% to 50% of drownings. Seizures, autism, and other developmental and behavioral disorders also increase the risk of drowning. In patients with prolonged QT syndrome, immersion in cold water may further extend the QT interval.

Submersion injuries can occur in natural bodies of water (freshwater and saltwater) as well as in domestic settings (such as bathtubs and swimming pools). Infants may even drown in toilets or buckets of water. However, if the infant is less than 6 months old or has an atypical presentation, healthcare providers should maintain a high suspicion for abuse. Efforts to decrease the incidence of submersion injuries and drowning deaths have focused on educating the public and increasing awareness of preventive measures. Preventive measures include adequate fencing around pools, decreasing the use of alcohol when engaged in water sports, increasing the supervision of children playing in or near water, and increasing the number of citizens trained in CPR. Water safety education for children, teenagers, and parents that encourages wearing flotation devices and never swimming alone should be reinforced in the school, community, and physician’s office.

Pathophysiology of Submersion Injuries

Victims of submersion injuries initially hold their breaths. As hypoxia and air hungerdevelop, they eventually involuntarily swallow and aspirate water. After aspiration of 1 to 3 mL/kg of water, dilution and washout of surfactant occurs, resulting in atelectasis, decreased gas exchange across the alveoli, non-cardiogenic pulmonary edema, and ventilation-perfusion mismatch. This leads to worsening hypoxia and respiratory and metabolic acidosis. If this process continues, neuronal death and cardiovascular collapse ensue.

“Dry drowning” is a term that was traditionally used to refer to drowning deaths that occurred without aspiration of a significant amount of water (perhaps due to severe laryngospasm, hypoxia, and loss of consciousness). However, the medical literature does not support this mechanism of injury. Dry drownings are probably due to causes besides simple submersion.

Management

Patients with submersion injuries may present with signs of pulmonary and central nervous system dysfunction or dysrhythmias. The patient may arrive in extremis with hypoxia, cyanosis, severe respiratory distress, or respiratory arrest. Other pulmonary findings may include tachypnea, wheezes, rales, or rhonchi. Neurologically, patient presentations may range from a mild alteration of consciousness to coma. Neurological deficits at the time of initial evaluation do not necessarily portend a poor patient outcome. Dysrhythmias are mainly the result of hypoxemia and acidosis and may include ventricular fibrillation, ventricular tachycardia, and bradycardia asystole. Patients with severe submersion injury may develop acute respiratory distress syndrome, hypoxic encephalopathy, or cardiac arrest.

All patients should be placed on continuous cardiac monitoring and pulse oximetry in the ED. An ECG is useful to rule out QT prolongation and dysrhythmias. A chest x-ray should also be performed to identify any infiltrates or pulmonary edema with the caveat that initial x-ray findings may progress over time. Although they are often normal at first, a baseline complete blood count, electrolytes, creatinine, and glucose should be obtained. Arterial blood gases may be helpful in monitoring for acidosis, hypercarbia, and hypoxemia. If a concern for rhabdomyolysis exists, serum creatinine kinase and urine myoglobin levels may be useful.

One of the most critical elements in the successful management of submersion victims is prompt and effective basic life support delivery in the prehospital setting. The Heimlich maneuver is no longer recommended to expel fluid from the lungs because of the high rate of aspiration induced by this maneuver and because of the delay it causes in initiation of ventilation. An awake patient with mild respiratory symptoms may benefit from noninvasive positive pressure ventilation (NIPPV) although a risk of gastric distention and vomiting does exist with the use of NIPPV. Indications for intubation include a lack of protective airway reflexes, respiratory distress, hypercarbia, hypoxia (despite noninvasive oxygen delivery), and apnea.

Intravenous fluids consisting of lactated Ringer solution or normal saline should be initiated in most victims. Glucose containing solutions are generally contraindicated except in hypoglycemic patients. Scientific investigations indicate that glucose solutions may worsen the neurological outcome in animals that have incomplete cerebral ischemia. In general, empiric antibiotics are not indicated for patients with submersion injuries. Antibiotics may benefit patients who were submerged in grossly contaminated water or manifest signs of infection.

Patients who are asymptomatic may be observed in the ED for 4 to 6 hours. If they maintain normal oxygen saturations on room air and have normal pulmonary examinations and chest x-rays, they may be discharged home. Admission is required for patients who are symptomatic, have been unconscious or hypoxic or apneic, have an abnormal chest x-ray, or have evidence of dysrhythmia.

Cold Water Submersion Injury

Submersion in cold water may be more advantageous than submersion in warm water due to induction of the diving reflex and hypothermia. In the diving reflex, blood is shunted away from the victim’s peripheral tissues to the heart and brain, decreasing metabolism and reducing anoxic injury. This reflex is strongest in children less than 6 months old and decreases with age. The protective effects of this reflex may partially account for reports of complete neurological recovery in children after prolonged submersion. Hypothermia has been theorized to be neuroprotective because of the induction of global hypometabolic state, leading to the conservation of oxygen and glucose for brain metabolism. Cold water also has potentially deleterious effects, most significantly cardiac irritability (leading to dysrhythmias), exhaustion, and altered mental status. Although some case reports have described patients who survived prolonged submersion in cold water, hypothermia is usually a poor prognostic indicator.

COMPREHENSION QUESTIONS

43.1 Each of the following patients is being treated for a submersion experience. Which one of the following is most appropriate for discharge from the ED after several hours of observation? A. A 3-year-old boy found face-down in the swimming pool, requiring 4 minutes of CPR, has a return of normal vital signs, with GCS score of 15, and mild respiratory distress.

B. A 12-year-old boy found unconscious and submerged in a swimming pool after striking his head on the bottom. His chest x-ray (CXR) and head CT are normal. His GCS score is 14. He is complaining of headache and no respiratory symptoms.

C. A 6-year-old boy who was washed into the ocean by a large wave and was rescued by a bystander. No CPR was required, and the boy had an initial GCS score of 14 and normal vital signs. CXR and physical examination are normal. Room air O2 saturation is 95%.

D. A 3-month-old infant who was brought to the ED after accidental submersion in the bathtub. The physical examination is unremarkable except for bruising over both arms and ankles. His CXR is normal and his room air O2 saturation is 98%.

43.2 Which of the following is a correct statement regarding submersion injuries?

A. Antibiotics may benefit patients who were submersed in grossly contaminated water.

B. The diving reflex is neuroprotective for adults who are submersed in cold water.

C. Neurological deficits on initial evaluation portend a poor prognosis.

D. A normal initial chest x-ray rules out pulmonary injury.

ANSWERS

43.1 C. Although the boy described in choice A is stable, his initial requirement for 4 minutes of CPR places him at a great risk for pulmonary and neurological sequelae. The patient described in B has mild respiratory symptoms, but his mechanism of injury and neurological findings are concerning for a closed head injury that requires further observation. The patient described in D is stable from the standpoint of a submersion injury, but the physical findings suggest possible intentional injury that may need further investigation.

43.2 A. Antibiotics may benefit patients who were submersed in grossly contaminated water or who have signs of infection on examination. The diving reflex is strongest in infants and children. Neurological deficits at the time of initial evaluation do not rule out the possibility of neurological recovery. Initial chest x-ray findings may progress over time.

CLINICAL PEARLS

⯈ Precipitants (such as alcohol use, seizures, and hypoglycemia) and associated cervical spine and head injuries must be considered in any submersion victim.

⯈ The most common complications involve pulmonary or central nervous system dysfunction or dysrhythmias.

⯈ The most important treatment to optimize outcome is rapid initiation of resuscitation in the prehospital arena . Victims of submersion injury often require aggressive respiratory support.

References

Bowers RC, Anderson TK. Chapter 44. Disorders due to physical and environmental agents. Stone CK, Humphries RL. eds. Current Diagnosis and Treatment: Emergency Medicine. 6th ed. Available at: http:// www.accessmedicine.com/content.aspx?aID=3113673. 

Causey AL, Nichter MA. Chapter 209. Drowning. In: Tintinalli JE, Stapczynski JS, Cline DM, Ma OJ, eds. Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, NY: McGraw-Hill; 2011. Available at: http://www.accessmedicine.com/content.aspx?aID=6379687. 

Causey AL, Tilelli JA, Swanson ME. Predicting discharge in uncomplicated near-drowning. Am J Emerg Med. 2000;18:9-11. 

Kuo DC, Jerrard DA. Environmental insults: smoke inhalation, submersion, diving, and high altitude. Emerg Med Clin N Am. 2003;21:475-497. 

Richards DB, Knaut AL. Drowning. In: Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Mosby Elsevier; 2011: Chapter 143. 

Volturo GA. Submersion injuries. In: Aaron CK, Abujamra L, eds. Harwood Nuss’ Clinical Practice of Emergency Medicine. 4th ed. Lippincott Williams & Wilkins; 2005: Chapter 356. 

Weinstein MD, Kriegr BP. Near-drowning: epidemiology, pathophysiology, and initial treatment. J Emerg Med. 1996;14:461-467.

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