Baseline chest radiographs, pulse oximetry, and arterial blood gases are typically recommended, although recent evidence suggests they may not be necessary in some asymptomatic cases.⁷

Cranial imaging with computed tomography (CT) can be useful if there is concern for traumatic head injury. The decision to use CT to evaluate for hypoxic injury is less clear-cut. A retrospective study of children who were victims of submersion incidents showed that CT often does not immediately show evidence of brain injury. The most common pattern of injury seen on delayed imaging (at 24 hours) was loss of grey-white matter differentiation consistent with hypoxic ischemic encephalopathy. Bilateral edema and bilateral basal ganglia infarcts were also appreciated. Intra- or extra-axial blood and unilateral abnormalities were not seen.⁸

Patients who have a normal room air oxygen saturation, normal pulmonary examination, and Glasgow Coma Scale score above 13 may be discharged home. All others should be admitted.^7,9

Contaminants

Freshwater lakes contain bacteria and protozoa. Seawater contains bacteria, algae, sand, and other particulates that can have a deleterious effect on the lung tissue, necessitating bronchoscopic lavage. Pool water is relatively devoid of bacteria, but chlorine can be irritating to the tracheobronchial tree, and it is very hypotonic. The major direct pulmonary insult is related to a reduction of surfactant and subsequent high surface tension and reduced compliance and atelectasis.

CRITICAL DECISION

Should prophylactic antibiotics be started in victims of submersion incidents?

Antibiotics should not be started prophylactically in all victims of submersion incidents. In patients who develop secondary lung infections, culture and sensitivity testing is essential to identify the causative agents and guide antimicrobial treatment, because microbes such as Aeromonas hydrophilia, which are not sensitive to common antibiotic regimens, can be present.3,4 If an Aeromonas infection is proved, aminoglycosides and second- or third-generation cephalosporins such as ceftazidime are preferred.

CRITICAL DECISION

What else should be considered when treating victims of submersion incidents?

Keep in mind the possibility that a medical emergency preceded and caused the submersion incident, especially in unusual instances such as an adult submerged in a bathtub.

Depending on the specific case and clinical suspicion, an ECG and cardiac testing, toxicology screening, anticonvulsant medication serum levels, etc., might be warranted.

In children, report any suspicious submersion incident to social services and the necessary authorities.

Case Resolution

Because the 9-year-old who had bumped his head while swimming had faint wheezing and coughing, the emergency physician decided to keep the child for observation for four hours. A chest radiograph was obtained and appeared normal. A few hours into his observation, the patient’s oxygen saturation was noted to be 92% on room air. Arterial blood gasses were obtained and revealed respiratory acidosis and mild hypoxemia, which was corrected with oxygen delivered by nasal cannula.