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Analysis: Hospitalization treatment in drowning cases
After drowning, patients must be moved quickly to ERs, even if asymptomatic. Every case requires thorough assessment, monitoring, and treatment.
Drowning: the asymptomatic and symptomatic patient in hospital
Laboratory and/or imaging tests are not always justified in asymptomatic patients. If required, workup should be directed towards the patient's history and examination (e.g. in the case of persistent hypoxia, a chest X-ray and haemogasanalysis may be justified).
The most common laboratory abnormality found in these patients is metabolic acidosis secondary to lactic acidosis. Electrolyte abnormalities are uncommon in drowning patients without a fatal outcome.
Chest X-ray is not necessary in all drowning patients. Furthermore, the initial chest X-ray has little correlation with the patient's clinical course or outcome. However, it should be performed in case of persistent hypoxia or worsening respiratory symptoms.
In summary, for an optimal hospital assessment of an asymptomatic or symptomatic drowning patient, one or more of these diagnostic investigations is performed, taking into account the history and specific clinical conditions:
- Anamnesis and objective examination.
- Haemogas analysis (probably the most reliable clinical parameter in asymptomatic or mildly symptomatic patients with a history of drowning).
- Blood sampling for rapid determination of glucose levels, obtaining a complete blood count, assessing electrolyte levels, lactate level and coagulation profile, if indicated.
- Urinalysis, to assess alcohol or drug intake.
- Chest X-ray.
The treatment of these patients is symptomatic.
An asymptomatic individual who, after drowning, has never developed symptoms or respiratory distress (e.g. has never had a cough), who remembers all events, and who has normal oxygen saturation and vital signs, can be discharged without prolonged observation. That is, provided that a responsible adult can ensure home monitoring. Patients should be instructed to return to the emergency department immediately if they develop any symptoms.
A patient who, following drowning, has not gone into cardiac arrest but has developed respiratory symptoms (e.g. coughing) requires observation for at least 8 hours. A drowning patient with normal oxygen saturation and a normal chest X-ray can be discharged if all the following criteria are met at the end of observation:
- Unaltered mental state.
- No new or worsening respiratory symptoms.
- If the patient has a cough, it must improve before discharge.
- Any subjective dyspnoea should resolve before discharge.
- Normal, age-adjusted vital parameters.
- The need for supplemental oxygen does not develop.
- Physiological lung auscultation.
The discharged patient must be given clear instructions to return immediately to the emergency department if respiratory symptoms worsen and be accompanied by a responsible adult.
Drowning: hospital treatment of the critical patient
Medical complications due to drowning usually require monitoring and treatment in an intensive care unit.
Respiratory complications
Respiratory compromise is typically manifested by dyspnoea, tachypnoea, coughing, cyanosis and wet crackles on auscultation, as well as foaming at the mouth in severe cases of pulmonary oedema. Nebulised beta-2-agonists may help reduce bronchospasm and dyspnoea. Initially, arterial haemogasanalysis will show hypoxaemia and metabolic acidosis that may progress to mixed acidosis.
Chest X-ray on admission may vary from normal to localised consolidations to diffuse pulmonary oedema.
The clinical picture is very similar to that of acute respiratory distress syndrome (ARDS). ARDS following a drowning event may occur immediately after rescue or within 6-24 hours. If ARDS develops, adequate oxygenation must be provided, with target oxygen saturation above 94% and normocapnia, especially if brain injury is suspected. If the level of consciousness is adequate, administer high-flow oxygen therapy or non-invasive ventilation (e.g. NIV, CPAP, BiPAP) if necessary. When indicated, the patient should be given invasive mechanical ventilation.
The use of ECMO is considered a good treatment option. Despite positive results, the use of ECMO in drowning patients needs to be further investigated.
Initial respiratory deterioration may be aggravated by primary infections caused by a wide variety of microorganisms or associated with ventilation. Empirical antibiotic treatment is not recommended, but may be considered taking into account the circumstances of drowning (e.g. drowning in contaminated water).
Neurological complications
Neurological damage may range from mild temporary cognitive dysfunction to a permanent vegetative state. In comatose patients, the neurological prognosis can only be predicted after at least five days, using a combination of clinical examination (Glasgow Coma Scale), continuous electroencephalogram, neuroimaging and neurophysiological tests, as well as the analysis of biochemical markers such as neuron-specific enolase (NSE).
With regard to treatment, recommendations include optimising oxygenation and maintaining homeostasis, with close monitoring of capnography, blood pressure, volaemia, osmosis and patient temperature.
Cardiovascular problems
Arterial hypotension is common immediately after resuscitation, as a consequence of low cardiac output or vasoplegia. Since most patients are young and healthy, transient hypotension usually corrects itself spontaneously.
Monitoring of diuresis, organ perfusion, haemogas and haemodynamic monitoring are essential to guide fluid management. Pharmacological treatment for haemodynamic stabilisation follows the general guidelines for critically ill patients, cautiously monitoring their use in case of hypothermia.
Rhythm disturbances, particularly supraventricular arrhythmias, are common in drowning patients and usually resolve with correction of hypoxia and acidosis. In addition, usually non-specific and transient electrocardiographic abnormalities may occur in hypothermic subjects.
Disseminated intravascular coagulation
Although this is a common complication in drowning patients, it has not been extensively studied. It is thought to be induced by hypoxia, which promotes the release of tissue plasminogen activator.
This disorder is manifested by high concentrations of D-dimer and anti-plasmin antibodies, low fibrinogen concentrations and prolonged clotting times.
Acute renal failure
Laboratory abnormalities in plasma and urine may be present in the first 72 hours. Acute renal failure is relatively uncommon. Its origin is multifactorial and usually reversible.
Electrolyte disturbances
Electrolyte changes due to intake/ ingestion of both fresh and salt water have been studied in animal models. However, their actual clinical significance is limited, as the redistribution of fluids in the body rapidly restores electrolyte balance.
Hospital management of hypothermia
The management of the patient's temperature is a critical aspect that may determine prognosis. Body temperature should be measured as soon as possible. Spontaneous hypothermia on admission is a strong predictor of poor prognosis.
Warming the drowned patient should be progressive, avoiding aggressive measures. With regard to therapeutic hypothermia, due to the scarce published literature on this procedure in drowning, no specific recommendations can be made.
A practical recommendation is to maintain an internal temperature of 32 to 34 °C and allow the body temperature to stabilise after a period of 12 to 72 hours of intensive care. Warming should be progressive up to a maximum of 0.5 °C/h. Both shivering and hyperthermia should be avoided during therapy.
Prognosis
Only alert or mildly confused patients at initial presentation have a good prognosis. Comatose individuals usually have a poor prognosis. They often develop severe brain injury and hypoxic encephalopathy. Hypothermia can protect the brain in some children.
Drowning prevention
At high risk of death by drowning are
- Children who are immigrants or from poor families.
- Children who have not had swimming lessons and are not supervised when they are near water.
- Males (80% of victims over the age of 1 year are men).
- Individuals who have used alcohol or drugs that disrupt thinking and vigilance.
- Persons with pathological conditions that cause temporary incapacity (e.g. epilepsy, which is associated with a 20-fold higher chance of drowning among children and adolescents.
- Persons with arrhythmogenic heart disorders.
- Persons practising dangerous sports (water apnoea).
All individuals with coronary artery disease, long QT syndrome (LQTS) or other ion channel disorders, autism, convulsive disorders or other medical conditions should be informed of the increased risk of drowning. In addition, they should be taught measures to reduce the risk, such as swimming in pairs and the use of life-saving devices. Given the higher rate of drowning in patients with epilepsy, patients should be warned never to swim without direct supervision.
It is recommended that all children over 1 year of age take swimming lessons. When boating or participating in water sports for which life jackets are recommended, persons should properly wear life jackets that comply with specific local regulations.
The use of alcohol and other psychoactive substances must be avoided before and during water activities.
Fence around a swimming pool (Image credits: steve, Adobestock)
General practitioners, family paediatricians and preventive medicine specialists play a key role in prevention. It is estimated that more than 85% of drowning cases could be prevented with supervision, attendance at swimming lessons, use of technology to increase safety, regulation and public education.
Parents, for example, should never leave children near water unsupervised. Remember that mini and toy pools are enough to drown an infant or small child. Parents should also place gates and fences around pools or other liquid containers (e.g. rainwater collection tanks). Children must always wear life jackets when in the water for sports (canoeing, SUP, ...). Furthermore, it is essential that parents or carers know how to perform cardiopulmonary resuscitation. For older children, the use of alcohol and drugs should be prohibited in swimming pools. Education is essential to prevent drowning.
The first part of this report is about first aid in drowning situations.