Near drowning and aspiration injury

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Submersion prevents effective gas exchange. Hypoxaemia leads to loss of consciousness, bradycardia and cardiac arrest; aspiration can wash out surfactant, injure the alveolar-capillary membrane and create ventilation-perfusion mismatch. Pulmonary oedema can evolve after circulation and spontaneous breathing return.

The central decisions are whether immediate ventilation and CPR are required, whether hypothermia or trauma modifies resuscitation, and whether a survivor is developing respiratory failure that needs escalating support. Water type and the amount reportedly swallowed are far less useful than physiology.

Aspiration pneumonitis is initially sterile inflammatory injury. Bacterial pneumonia may develop later, particularly after grossly contaminated water or prolonged ventilation, but early fever or infiltrates do not automatically prove infection. Serial clinical assessment is therefore more informative than reflex antimicrobial treatment.

Key points

Use the terms fatal or non-fatal drowning; the older phrase near drowning does not describe severity or outcome reliably.
Rescuers must not become additional casualties. Reach, throw or use a flotation device, and activate the ambulance service or Coastguard before a trained in-water rescue when possible.
Drowning arrest is primarily hypoxic, so rescue breaths matter: current RCUK guidance gives five initial breaths before standard CPR on land or a rescue boat.
Trained rescuers may give five in-water rescue breaths only when it is feasible and safe with effective flotation; retrieval must otherwise take priority.
Do not use abdominal thrusts or prolonged positioning to expel water. These delay ventilation and increase regurgitation and aspiration.
Suspect cervical injury only when the mechanism supports trauma, such as diving into shallow water, collision or a fall; routine immobilisation can obstruct airway care.
Fresh water and salt water do not require different initial resuscitation. Hypoxaemia, ventilation, temperature, trauma and complications drive treatment.
Cough, tachypnoea, crackles, hypoxaemia or reduced consciousness after rescue may progress to non-cardiogenic pulmonary oedema and acute respiratory distress over hours.
Prophylactic antibiotics and corticosteroids are not routine after water aspiration; treat established infection or exceptional gross contamination with microbiology advice.
Any persistent respiratory, neurological or temperature abnormality warrants monitored hospital care and serial reassessment, even after apparent early improvement.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Unintentional immersion

Falls, swimming difficulty, flooding and water recreation cause most events, with risk increased by absent supervision or flotation.

Impaired consciousness

Alcohol, drugs, seizure, arrhythmia, hypoglycaemia and neurological disease can precipitate submersion and may remain the underlying emergency.

Trauma and environment

Diving injury, cold water, currents and entrapment complicate rescue and add cervical, head or hypothermic injury.

Medical vulnerability

Young children, older adults and people with cardiac or respiratory disease have less reserve and may deteriorate after a brief aspiration event.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Submersion hypoxia
Breath holding progresses to involuntary inspiration, aspiration or laryngospasm, rapidly depleting oxygen and causing loss of consciousness.
2
Surfactant disruption
Aspirated water washes out or inactivates surfactant, injures epithelium and promotes patchy alveolar collapse, which helps produce the characteristic physiological impairment.
3
Permeability oedema
Alveolar-capillary injury permits protein-rich fluid to enter air spaces, creating shunt and evolving hypoxaemic respiratory failure.
4
Whole-body reperfusion injury
After hypoxic arrest, reperfusion and inflammation can injure brain, heart, kidneys and other organs even when ventilation is restored.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Respiratory arrestRed flag

Unresponsiveness with absent or abnormal breathing after submersion indicates cardiac arrest or imminent arrest. Agonal gasps are not normal breathing; begin ventilations and compressions without waiting for a pulse oximeter.

Aspiration lung injuryRed flag

Persistent cough, tachypnoea, increased effort, crackles, frothy sputum, cyanosis or an oxygen requirement after rescue suggests alveolar injury. Deterioration may occur despite an initially clear radiograph.

Neurological injuryRed flag

Confusion, agitation, seizure, coma or focal signs may reflect hypoxia, head or cervical trauma, hypoglycaemia, intoxication or stroke. Do not ascribe altered consciousness solely to cold exposure.

Clinically important hypothermiaRed flag

Cold skin, shivering followed by reduced shivering, bradycardia, confusion, impaired consciousness or rigidity suggests falling core temperature. In an unconscious hypothermic person, RCUK advises checking vital signs for up to one minute.

Associated traumaRed flag

Scalp injury, neck pain, neurological deficit, chest-wall injury or a diving, boating or high-energy mechanism warrants trauma assessment alongside resuscitation. Airway and ventilation still take priority.

Developing infection

New or persistent fever, purulent secretions, rising inflammatory markers and worsening focal or diffuse infiltrates after the initial inflammatory phase raise pneumonia; gross sewage or unusual water exposure changes likely organisms.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
ABCDE assessment and serial pulse oximetryFirst step
Why
Identify respiratory failure, shock, neurological impairment and trauma.
Interpretation and limitations
Record oxygen delivery and work of breathing. Normal saturation after oxygen does not prove mild injury; falling requirement and stable effort over observation are more reassuring.
02
Core temperature
Why
Diagnose hypothermia and guide modified resuscitation and rewarming.
Interpretation and limitations
Use a low-reading core thermometer where available. Peripheral readings are unreliable in severe cold exposure; clinical staging can guide care when core measurement is not possible.
03
Arterial or venous blood gas
Why
Assess ventilation, acidosis, lactate and response to resuscitation.
Interpretation and limitations
Severe acidosis and lactate reflect hypoxia, arrest, shock or seizures and should be trended. ABG is needed when precise oxygenation will change respiratory support.
04
Chest radiograph
Why
Assess aspiration change, pulmonary oedema and traumatic complications.
Interpretation and limitations
Early imaging may be normal and radiographic severity can lag physiology. Bilateral opacities are compatible with lung injury but also require assessment for cardiogenic oedema and infection.
05
ECG and metabolic panel
Why
Detect arrhythmia, electrolyte disturbance, glucose abnormality and organ injury.
Interpretation and limitations
Bradyarrhythmias may accompany hypothermia; glucose abnormalities, sodium disturbance and renal injury need correction. Routine freshwater-versus-seawater electrolyte assumptions are clinically unreliable.
06
Trauma and toxicology-directed imaging
Why
Investigate injuries or an underlying cause of submersion.
Interpretation and limitations
CT head, cervical spine or body imaging is driven by mechanism, examination and consciousness. Consider alcohol, drugs, seizure, arrhythmia and deliberate self-harm without delaying resuscitation.
07
Microbiology sampling
Why
Guide antibiotics when pneumonia or gross contamination is credible.
Interpretation and limitations
Obtain respiratory and blood cultures in severe infection where feasible. Alert microbiology to freshwater, seawater, sewage or soil exposure because unusual Gram-negative, fungal or other organisms may matter.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Primary cardiac event

Arrhythmia or myocardial ischaemia may have caused the immersion; electrocardiographic and clinical assessment should not assume water was the sole problem.

Seizure or neurological event

Witnessed movements, focal deficits or prior epilepsy suggests a neurological precipitant, while hypoxia itself can also cause seizure.

Diving barotrauma

Neurological deficits or chest symptoms immediately after compressed-gas ascent may indicate arterial gas embolism or pleural air rather than water aspiration alone.

Immersion pulmonary oedema

Acute dyspnoea during surface swimming with frothy sputum but no submersion may reflect hydrostatic immersion-related oedema.

Cervical or head trauma

Diving, boating and falls can cause occult injury that alters airway management and neurological interpretation, and the distinction changes the subsequent clinical pathway.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01RescueVentilate a drowning casualty promptlyFirst stepA person is unresponsive and not breathing normally after submersion.

1Call 999 or the Coastguard, use safe rescue equipment and retrieve the person to land or a boat; trained rescuers may give five in-water breaths only with secure flotation.
2Once on a firm surface, open the airway, give five rescue breaths and then begin standard CPR with an AED as soon as available.
3Do not spend time expelling water or performing abdominal thrusts; clear visible vomit, use suction when available and resume effective ventilation promptly.
4Continue advanced resuscitation, treat hypothermia and reversible causes, and transfer to an appropriate emergency department even when circulation returns.

02Respiratory supportEscalate aspiration-related lung injuryEscalationOngoing hypoxaemia, increasing work of breathing, fatigue or bilateral pulmonary opacities.

1Give titrated oxygen and monitor closely, obtaining a blood gas and early critical-care review when requirement or effort is increasing.
2Use non-invasive support only in a cooperative patient who can protect the airway and is closely observed; intubate for exhaustion, impaired consciousness or refractory gas-exchange failure.
3Apply lung-protective ventilation and appropriate PEEP for acute respiratory distress, with prone positioning or ECMO considered under current critical-care pathways when severe.
4Use conservative, haemodynamically appropriate fluid management after perfusion is restored and reassess for pneumothorax, aspiration pneumonia or cardiac dysfunction.

03HypothermiaRewarm without harming resuscitationMeasured or clinically suspected significant hypothermia after immersion.

1Remove wet clothing, insulate, handle gently, measure core temperature and prevent further heat loss while continuing oxygenation and circulation support.
2Use active external or internal rewarming matched to severity and haemodynamic stability, involving critical care and a specialist centre for unstable or profound hypothermia.
3Follow the current RCUK hypothermic-arrest modifications for drug and shock timing; do not invent local thresholds from memory during resuscitation.
4Continue post-resuscitation temperature management and monitor for afterdrop, arrhythmia, electrolyte shifts, coagulopathy and associated cold injury.

04SurvivorObserve and discharge by physiologySpontaneous circulation and breathing have returned after a non-fatal drowning event.

1Take a full event history, examine repeatedly and monitor oxygenation, respiratory effort, consciousness and temperature for the period specified by the local emergency pathway.
2Admit anyone with symptoms, abnormal examination, oxygen need, radiographic change, hypothermia, significant comorbidity, trauma, intoxication or an unsafe psychosocial context.
3Do not give routine antibiotics or steroids; treat bronchospasm, infection, seizures or other complications only when clinically established.
4Discharge only when observation remains normal, with responsible supervision, written return advice and follow-up for the precipitating medical, safeguarding or mental-health issue.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Correct hypoxaemia while ventilation and aspiration-related lung injury are assessed.

Supplemental oxygen

Use high concentration during resuscitation, then titrate to 94-98% saturation or an individual 88-92% target when hypercapnic risk exists.

A normal reading on oxygen does not establish recovery. Escalate support for work of breathing or fatigue, and use blood gases when ventilatory failure is possible.

Treat bacterial infection after contaminated aspiration or a developing pneumonia.

Antibiotic therapy

Do not prescribe prophylactically; when pneumonia is established, follow local severe-pneumonia guidance modified by exposure history and microbiology advice.

Initial chemical pneumonitis can cause fever and infiltrates without infection. Gross sewage, freshwater or seawater exposure may require unusual coverage; obtain expert advice rather than guessing.

Relieve an associated bronchospastic component after aspiration or cold exposure.

Inhaled bronchodilator

Give salbutamol according to the current acute bronchospasm protocol when wheeze and reversible airflow obstruction are clinically present.

Bronchodilator does not treat alveolar oedema or remove aspirate. Tachycardia and lactate elevation can complicate reassessment, so judge response clinically.

Support circulation in persistent post-arrest or hypothermic shock.

Vasoactive support

Use a critical-care infusion protocol titrated to perfusion after appropriate volume assessment and correction of hypoxia and temperature.

Drug responsiveness and arrhythmia risk change with profound hypothermia. Follow RCUK modifications and specialist rewarming advice rather than routine normothermic escalation.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Hypoxic brain injury

Duration and severity of oxygen deprivation drive coma, cognitive impairment, seizures and death after resuscitation, and increasing the burden of otherwise local respiratory disease.

Acute respiratory distress syndrome

Aspiration-related permeability injury may worsen over hours, producing severe shunt and need for prolonged ventilation, creating an additional need for recognition and targeted treatment.

Cardiac dysfunction and arrhythmia

Hypoxia, acidosis, cold and catecholamine stress can cause myocardial stunning, rhythm disturbance and recurrent arrest, and increasing the burden of otherwise local respiratory disease.

Hypothermia

Cold immersion slows metabolism but also impairs coagulation and circulation and complicates reliable neurological assessment, with severity determined by its extent and the patient's underlying reserve.

Secondary infection

Contaminated water and prolonged ventilation can lead to pneumonia, but infection is assessed clinically rather than assumed after every aspiration.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Trend respiratory rate, work of breathing, SpO2, oxygen delivery and auscultation because lung injury can evolve after an apparently successful rescue.
Repeat blood gas and chest imaging when oxygen need or effort changes; do not schedule tests solely by time if the patient is deteriorating sooner.
Record Glasgow Coma Scale, pupils, glucose and seizures, reassessing neurological recovery after oxygenation, perfusion and temperature are corrected.
Monitor core temperature, rhythm, blood pressure, electrolytes, glucose, urine output and coagulation during moderate or severe hypothermia and rewarming.
Watch for infection over the subsequent clinical course rather than treating the initial aspiration event automatically; culture before antibiotics when this is safe.
After discharge, make return precautions explicit for breathlessness, persistent cough, fever, chest pain, confusion, fainting or reduced exercise tolerance.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Ventilation changes the trajectory

Drowning arrest begins with hypoxia, so five initial rescue breaths are a deliberate departure from compression-first messaging used for many sudden adult cardiac arrests.

Water does not need draining

Most aspirated liquid cannot be removed by positioning or thrusts. Attempts delay oxygenation and increase vomiting; airway opening, ventilation and suction of visible material are useful.

Salt does not choose the algorithm

Historically described electrolyte differences rarely drive early care. Both freshwater and seawater drowning are treated according to gas exchange, circulation, temperature and complications.

Radiographs can lag physiology

A clear first film does not guarantee a harmless event. Respiratory effort and oxygen requirement across a suitable observation period are the safety signal.

Submersion may be the consequence

Seizure, arrhythmia, hypoglycaemia, intoxication, trauma or self-harm may have caused entry into the water. Identifying the precipitant prevents a second event.

11Common pitfallsFrequent interpretation and management errors.

01
Entering the water without training or flotation and creating another casualty.
02
Starting chest compressions but omitting the five initial rescue breaths in drowning arrest.
03
Using abdominal thrusts or head-down drainage to remove water before ventilating.
04
Immobilising every rescued person and allowing a collar or board to delay airway care without a traumatic mechanism.
05
Reassuring from one normal chest radiograph or saturation measured on supplemental oxygen.
06
Giving prophylactic antibiotics or corticosteroids after uncomplicated aspiration.
07
Using the freshwater or saltwater label to distract from hypoxia, hypothermia, trauma and evolving lung injury.
08
Missing the medical, safeguarding or mental-health cause that preceded submersion.