7. Near Drowning

Quick Recap

Trauma System, Protocol 7/8. Drowning-associated hypothermia management draws on the ATLS 11th Edition tiered hypothermia correction framework and ICU Protocols stepwise hypothermia algorithm (both directly applicable given frequent co-occurrence); the pulmonary injury pattern is managed per the ARDS protocol (Respiratory System), since drowning/near-drowning is an explicitly recognized direct cause of ARDS.

1. Definition and Terminology

Current WHO-endorsed terminology: "drowning" describes the process of experiencing respiratory impairment from submersion/immersion in liquid — outcomes are classified as death, morbidity, or no morbidity, replacing the older, inconsistent terminology ("near-drowning," "dry drowning," "secondary drowning," "wet drowning") that caused confusion in prior literature and clinical teaching. "Dry drowning" (death from pure laryngospasm without aspiration) is now understood to be RARE, accounting for only a small minority of drowning deaths — the vast majority of drowning victims DO aspirate fluid, and management should proceed on this assumption rather than anchoring on the older, largely discredited dry-drowning framework.

2. Pathophysiology

Submersion -> initial breath-holding -> involuntary laryngospasm/aspiration attempts -> hypoxemia -> loss of consciousness -> aspiration of water (in the large majority of cases) -> surfactant washout and dysfunction, alveolar-capillary membrane injury, and a pattern of pulmonary edema/ARDS-like injury — mechanistically similar regardless of fresh vs salt water (the older teaching emphasizing major electrolyte/osmotic differences between fresh and salt water drowning has been substantially de-emphasized; the DOMINANT clinical problem in both is the pulmonary injury/hypoxemia, not electrolyte derangement). Near drowning is an explicitly recognized DIRECT cause of ARDS (see ARDS protocol, Respiratory System, Berlin Definition etiology table) — apply the full ARDS management framework (lung-protective ventilation, proning for P/F <150, conservative fluid strategy) once this pattern develops.

Concurrent hypothermia is extremely common, particularly in cold-water submersion, and carries its own distinct management framework (Section 5) that must run in parallel with respiratory/cardiovascular resuscitation, not as an afterthought.

3. Immediate Stabilization (ABCDE)

Airway/Breathing:

• Standard airway/breathing support per hypoxemic respiratory failure principles; oxygen for all drowning victims regardless of initial presentation, given the potential for delayed pulmonary deterioration
• Do NOT perform abdominal thrusts (Heimlich maneuver) or other water-expulsion techniques as a resuscitation step — these delay effective ventilation/compressions and risk aspiration of gastric contents without proven benefit; focus resuscitation on standard airway management and ventilation
• Intubate per standard hypoxemic respiratory failure/GCS criteria; anticipate potential aspiration pneumonitis and evolving ARDS-pattern lung injury even if the initial presentation appears mild
• A patient who appears initially well after a submersion event can still deteriorate over the following HOURS as aspiration-related pulmonary injury evolves — observation is warranted even in apparently asymptomatic/mildly symptomatic presentations, particularly following any period of witnessed struggle, loss of consciousness, or aspiration

Circulation:

• Standard resuscitation per ACLS principles for cardiac arrest; hypothermia significantly alters resuscitation dynamics and prognosis (Section 5) — "not dead until warm and dead" is the guiding principle for continued resuscitation efforts in hypothermic cardiac arrest specifically, given hypothermia's neuroprotective effect against the ischemic insult
• Treat any concurrent trauma (diving injuries, cervical spine injury from shallow-water impact) per standard trauma principles — maintain cervical spine precautions if the mechanism suggests possible diving/impact injury, though routine C-spine immobilization for all drowning victims without a suggestive mechanism is not universally recommended given low injury incidence in that broader population

Disability/Exposure:

• Assess and document neurologic status; hypoxic-ischemic brain injury is the dominant driver of poor neurologic outcome in drowning survivors, analogous to the post-cardiac-arrest hypoxic-ischemic injury framework (see Post-Cardiac Arrest Syndrome protocol, Neurology System, for the shared neuroprognostication principles once the patient is stabilized and appropriately re-warmed)
• Actively assess core temperature in every drowning patient, especially cold-water submersion — hypothermia is common and changes both resuscitation approach and prognosis (Section 5)

Checklist:

4. Severity Assessment and Disposition

No universally mandated single severity score for drowning analogous to some other trauma entities, but clinical grading systems exist to guide disposition (e.g., grading from asymptomatic/cough-only through to cardiac arrest) — even patients with an apparently mild initial presentation warrant a period of observation (commonly 4-8 hours, individualized per institutional protocol and clinical trajectory) given the risk of delayed pulmonary deterioration described in Section 3. ICU-level care is indicated for: any respiratory distress/hypoxemia, altered mental status, hemodynamic instability, significant hypothermia, or cardiac arrest with return of spontaneous circulation.

5. Hypothermia Management — Full Staged Framework

Drowning-associated hypothermia should be managed using the same staged approach applied to any accidental hypothermia:

Key technique principles:

• Rewarm the TRUNK BEFORE the extremities — active external warming of extremities first can cause peripheral vasodilation that shunts cold, acidotic peripheral blood back to the core, causing a PARADOXICAL FURTHER DROP in core temperature (the "after-drop" phenomenon) — apply rewarming devices to the trunk only to minimize this risk
• Rewarming rate target: 1-2.5C/h
• Active internal warming methods: warm IV fluids, warm/humidified oxygen, peritoneal lavage, gastric/esophageal lavage, bladder/rectal lavage, pleural lavage, intermittent hemodialysis
• ECMO/cardiopulmonary bypass is the rewarming method of choice for cardiac arrest with severe hypothermia (core temp <30C) and/or hyperkalemia — provides circulation, oxygenation, and ventilation simultaneously while core temperature rises; if unavailable, combine invasive rewarming methods
• Withhold cardioactive drugs and further defibrillation attempts until core temperature reaches 30C (hypothermic myocardium is often refractory to both) — continue basic life support until this threshold
• Atrial arrhythmias: monitor WITHOUT intervention — ventricular response is typically slow, and most convert spontaneously during rewarming
• Preexisting ventricular ectopy may be SUPPRESSED by hypothermia and can REAPPEAR during rewarming — anticipate this, do not be falsely reassured by an initially quiet rhythm
• If core temperature fails to respond to warming efforts, consider underlying infection or endocrine derangement (myxedema, adrenal insufficiency) as a contributing/alternative cause — empiric broad-spectrum antibiotics and glucocorticoids may be reasonable while this is worked up; actively screen for and treat hypoglycemia
• Hypothermia at any stage causes coagulation dysfunction and decreased platelet aggregation, which can complicate management of any concurrent hemorrhage (relevant if drowning co-occurs with trauma) — same "lethal triad" principle as in the Hypovolemic Shock protocol

6. Post-Resuscitation Complication Surveillance

After initial stabilization/rewarming, actively monitor for: hypotension during active rewarming (vasodilation effect), arrhythmias, rhabdomyolysis (see dedicated Rhabdomyolysis protocol, Renal System, if suspected — relevant given prolonged struggling/hypoxia), bleeding diathesis (hypothermia-related coagulopathy), hypokalemia, hypoglycemia, bladder atony, and infection (aspiration pneumonia, particularly with contaminated/non-sterile water sources).

7. Investigations

Core temperature (continuous monitoring), ABG (hypoxemia/acid-base status), CXR (aspiration pneumonitis/evolving ARDS pattern — may lag behind clinical severity), electrolytes, renal function, CK (rhabdomyolysis screening), coagulation panel (hypothermia-associated dysfunction), ECG (Osborn/J waves classically associated with hypothermia, arrhythmia screening), blood cultures/respiratory cultures if infection suspected (contaminated water source raises atypical/resistant organism consideration), toxicology screen if intentional drowning/substance use is a possible contributing factor.

8. Organ Support

Lung-protective ventilation and full ARDS management per the dedicated protocol if that pattern develops; staged hypothermia rewarming per Section 5; ECMO for combined refractory hypoxemia AND/OR severe hypothermic cardiac arrest; standard post-cardiac-arrest care (see Post-Cardiac Arrest Syndrome protocol, Neurology System) if ROSC achieved, INCLUDING appropriately delayed/modified neuroprognostication timing given hypothermia's confounding effect on neurologic exam reliability; standard ICU supportive care.

9. Consultation Matrix

10. Monitoring Framework

Continuous core temperature during active rewarming, continuous cardiac monitoring (arrhythmia surveillance through rewarming), serial ABG/oxygenation trend, serial CXR if pulmonary injury evolving, serial CK/renal function if rhabdomyolysis a concern, extended observation period for apparently mild presentations given delayed deterioration risk.

11. Complications

ARDS/evolving pulmonary injury (can lag the initial presentation by hours), hypoxic-ischemic brain injury, hypothermia-associated arrhythmia and coagulopathy, after-drop phenomenon from incorrect rewarming technique sequencing, rhabdomyolysis, aspiration pneumonia (potentially with atypical/water-source-specific organisms), rewarming-associated hypotension. Prevention: extended observation for apparently mild presentations, trunk-first rewarming technique, appropriate ECMO/extracorporeal rewarming threshold for severe hypothermic arrest, standard ARDS-protective ventilation once that pattern is recognized. Rescue: standard ARDS rescue therapies (proning, ECMO), extracorporeal rewarming for refractory hypothermic arrest, standard arrhythmia/coagulopathy management during rewarming.

12. Escalation & De-escalation

Escalate: evolving respiratory failure/ARDS pattern -> full ARDS protocol management; hypothermic cardiac arrest -> continue resuscitation per the "not dead until warm and dead" principle, escalate to ECMO/extracorporeal rewarming if core temp <30C or hyperkalemic.

De-escalate: observation period completed without deterioration (mild presentations), core temperature normalized without arrhythmia, oxygenation stable -> transition to standard ward-level monitoring or discharge per institutional protocol.

13. ICU Discharge Criteria

Respiratory status stable (past the delayed-deterioration risk window), core temperature normalized and stable without arrhythmia, no evidence of ongoing aspiration pneumonia requiring ICU-level care, neurologic status stable or appropriately assessed once re-warmed, psychiatric evaluation completed if intentional submersion suspected.

14. Documentation & Medicolegal Checklist

15. Key Guidelines

World Health Organization consensus definition and classification of drowning (van Beeck et al., Bull World Health Organ, 2005). American College of Surgeons. Advanced Trauma Life Support, 11th Edition Course Manual, 2023 (Chapter 8: Exposure and Environmental Threats — hypothermia staging framework applied here).

16. Controversies

The optimal observation duration for apparently mild/asymptomatic drowning presentations before safe discharge is not rigidly standardized across institutions, reflecting genuine practice variation in balancing resource use against the real but variably-quantified delayed-deterioration risk. The precise core temperature threshold and duration for terminating resuscitation efforts in hypothermic cardiac arrest ("not dead until warm and dead") lacks a single universally agreed cutoff, and extracorporeal rewarming availability significantly influences this threshold in practice. The historical fresh-water vs salt-water electrolyte-differences teaching, while now de-emphasized clinically, still appears in some older references and can create confusion if not explicitly addressed.

17. References

1. van Beeck EF, Branche CM, Szpilman D, Modell JH, Bierens JJ. A new definition of drowning: towards documentation and prevention of a global public health problem. Bull World Health Organ. 2005;83(11):853-856.
2. Dureja J, et al. Heat Stroke and Hypothermia. ICU Protocols: A Step-wise Approach, 2nd ed. Springer; 2020 (Ch. 17).
3. American College of Surgeons. Advanced Trauma Life Support, 11th Edition Course Manual, 2023 (Chapter 8: Exposure and Environmental Threats in the Primary Survey).
4. Grotberg JC, Kraft BD. Acute Respiratory Distress Syndrome (near drowning as a direct ARDS cause). Washington Manual of Critical Care, 4th ed, 2025 (Ch. 11).
5. Brown DJ, Brugger H, Boyd J, Paal P. Accidental hypothermia. N Engl J Med. 2012;367(20):1930-1938.
6. Szpilman D, Bierens JJ, Handley AJ, Orlowski JP. Drowning. N Engl J Med. 2012;366(22):2102-2110.

See also: ARDS (Respiratory System) for the full lung-protective ventilation and rescue therapy detail for the drowning-associated pulmonary injury pattern; Post-Cardiac Arrest Syndrome (Neurology System) for neuroprognostication principles once appropriately re-warmed; Rhabdomyolysis (Renal System) for the related complication management framework.