Drowning Resuscitation

Quick Answer

Drowning is a respiratory impairment process caused by submersion/immersion in liquid, leading to hypoxia and potentially cardiac arrest. Immediate management prioritizes oxygenation and ventilation: give 5 rescue breaths first, then start CPR if no response (30:2 compression:ventilation ratio in adults, 15:2 in children). Hypothermia is treated simultaneously if present (passive rewarming ≥35°C, active if below). Complications include ARDS, hypothermia, and drowning-associated pneumonia requiring broad-spectrum antibiotics.

ACEM Exam Focus

Primary Exam: Pathophysiology of drowning, difference between saltwater and freshwater, hypothermia physiology

Fellowship Exam:

• 5 rescue breaths before compressions (ANZCOR 9.3.2)
• Start compressions if drowning duration below 1 minute
• Hypothermia management and prognostication
• ARDS recognition and ventilation strategies
• Indigenous and remote/rural considerations

Key Points

1. 5 rescue breaths before compressions - Hypoxia is primary problem, not cardiac arrest
2. Ventilations-first CPR - Treat respiratory arrest first, then cardiac arrest if needed
3. Compressions only if drowning below 1 minute - Otherwise start rescue breaths immediately
4. Hypothermia may be protective - Targeted temperature management post-arrest
5. ARDS develops in 15-50% - Can be delayed up to 24 hours post-drowning
6. Broad-spectrum antibiotics - Cover aquatic pathogens (Aeromonas, Pseudomonas, Vibrio)
7. Indigenous Australians 3x risk - Remote/rural drowning rates significantly higher

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Epidemiology

Global Burden

• Leading cause of death worldwide: 236,000 deaths annually
• WHO estimate: 7% of all injury-related deaths
• greater than 90% deaths in low- and middle-income countries
• Leading cause death boys 5-14 years old globally

Australian Epidemiology

• Annual drowning deaths: 250-300 (0.8-1.0 per 100,000)
• Non-fatal drowning events: 3-5,000 annually
• Males: 75-80% of all drowning deaths
• Peak age groups: 0-4 years (pool drowning), 15-24 years (rivers, beaches)

High-Risk Populations in Australia

• Aboriginal and Torres Strait Islander: 3x non-Indigenous risk
• Migrants: 34% of drowning fatalities (swimming unfamiliar waters)
• Rural and remote: 2-3x urban drowning mortality
• Children under 5: Leading cause injury death

Location Distribution

• Rivers/creeks: 30% of drowning deaths
• Oceans/beaches: 25%
• Pools: 15%
• Lakes/dams: 10%
• Bath: 5% (children under 5)

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Pathophysiology

Definitions (WHO 2002 Consensus)

Drowning: Process of respiratory impairment from submersion/immersion in liquid

Outcomes:

• Death
• Non-fatal drowning with morbidity
• Non-fatal drowning without morbidity

Terms no longer recommended: near-drowning, wet vs dry drowning, secondary drowning

Sequence of Events

1. Immersion - Face in water, breath-hold
2. Laryngospasm (10-15% only) - Protective reflex prevents aspiration
3. Aspiration (85-90%) - Water enters airway and alveoli
4. Hypoxia - Respiratory impairment = hypoxaemia
5. Hypercapnia - CO2 accumulation leads to respiratory acidosis
6. Cardiac arrest - Hypoxia → myocardial ischemia → ventricular fibrillation asystole

Saltwater vs Freshwater Drowning

Clinical Relevance:

• Both cause surfactant depletion and hypoxia as primary problem
• Freshwater massive haemolysis: Haemoglobinuria (red urine), AKI from pigment nephropathy
• Saline resuscitation preferred: Corrects hypernatraemia in saltwater, hyponatraemia in freshwater
• Fluid management differs: Freshwater may require fluid restriction; saltwater often needs diuresis for pulmonary edema

Note: Clinical distinction rarely important; both cause hypoxia as primary problem

Respiratory Pathophysiology

Surfactant Washout:

• Freshwater: 4-10 mL per kg body weight destroys surfactant
• Saltwater: Surface tension effects disrupt surfactant

Alveolar-Capillary Membrane Disruption:

• Chemical injury to type I pneumocytes
• Increased permeability → pulmonary edema
• Atelectasis: V/Q mismatch, shunting

ARDS Development (15-50% of drowning survivors):

• Onset: 2-24 hours post-drowning
• Pathology: Hypoxic respiratory failure
• Criteria: PaO2/FiO2 below 200, bilateral infiltrates, non-cardiac

Cardiovascular Pathophysiology

Hypoxia-Induced Arrhythmias:

• PaO2 below 60 mmHg → ventricular arrhythmias
• Initial respiratory arrest → subsequent cardiac arrest
• Cardiac arrest usually secondary to prolonged hypoxia
• VF/VT most common initial rhythm in children and adults

Cold Water Diving Reflex (sudden cold water immersion to facial region):

• Immediate bradycardia (parasympathetic via trigeminal nerve)
• Peripheral vasoconstriction (sympathetic surge)
• Central blood shunting: preserves cerebral and coronary circulation
• Allows prolonged submersion without cardiac arrest in cold water (below 20°C)
• More pronounced in children and more pronounced in cold water

Hypothermia Effects:

• Below 35°C: Bradycardia, decreased cardiac output
• Below 30°C: Risk of ventricular fibrillation (RV cooling)
• Below 20°C: Asystole, profound neuroprotective effect possible
• Hypothermia increases ventricular fibrillation threshold initially, but cooling greater than 28°C then increases arrhythmia risk

Freshwater-Associated Effects:

• Massive haemolysis possible with greater than 1500 mL freshwater
• Hyperkalaemia from potassium release → arrhythmias
• Circulatory overload from fluid absorption
• Hemoglobinuria can cause acute kidney injury (pigment nephropathy)

Neurological Pathophysiology

Hypoxic-Ischemic Brain Injury:

• Neurons begin dying after 4-6 minutes complete hypoxia
• Major pathways: Excitotoxicity (glutamate), oxidative stress, inflammation
• Outcomes: Normal recovery, neurodisability, persistent vegetative state, brain death

Hypothermia Neuroprotection:

• Each 1°C drop reduces cerebral metabolic rate 5-7%
• Temperature below 20°C: Possible neurologic recovery despite prolonged submersion

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Clinical Approach

Initial Assessment: ABCDE

A - Airway:

• Cervical spine immobilization only if trauma suspected (diving accident, fall from height)
• OPA/NPA if GCS below 8 or obstructed airway
• Suction oropharynx immediately if water present
• Intubate early: GCS below 9, respiratory fatigue, hypoxaemia (SpO2 below 90% despite oxygen)

B - Breathing:

• Oxygen 15 L/min via non-rebreather mask initially
• Bag-valve-mask ventilation if respiratory effort inadequate
• Rapid sequence intubation parameters: PaO2 below 60 mmHg, RR above 30, PaCO2 above 45
• Ventilator settings: PEEP 5-10 cmH2O, tidal volume 6-8 mL/kg, FiO2 titrated to SpO2 94-98%

C - Circulation:

• Obtain access: Two large-bore IVs or intraosseous
• Normal saline/blood products as needed for hypovolaemia
• Vasopressors if hypotension persists after fluids: Noradrenaline 0.05-0.5 mcg/kg/min

D - Disability: Neurological Assessment:

• GCS on arrival and serial
• Pupillary response fixed/dilated = poor prognostic sign (specificity 85% for poor outcome)
• Temperature measurement (core: rectal, bladder, or oesophageal)

E - Exposure:

• Remove wet clothing, prevent further heat loss (passive rewarming)
• Inspect for trauma (head, spine, ribs, long bones)
• Look for signs of submersion injury (skin maceration, debris, water in ears)

Specific Assessment Features

Key Historical Points:

• Drowning duration (important for prognosis)
• Water temperature (cold water = better outcome possibility)
• Submersion depth (diving vs surface)
• Prior illness/cardiac history (seizure, arrhythmia, drugs)
• Bystander CPR quality and timing

Vital Sign Abnormalities Indicating Severity:

• Temperature below 30°C (profound hypothermia)
• SpO2 below 80% despite high oxygen
• PaCO2 below 30 mmHg (hyperventilation) or above 50 mmHg (fatigue)
• Lactate above 4 mmol/L (tissue hypoperfusion)
• Base deficit below minus5

Physical Exam Key Findings:

• Pulmonary: Crackles, wheeze, rhonchi (edema, bronchospasm)
• Cardiovascular: Bradycardia (hypothermia), thready pulses
• Neurological: Coma, seizures, decerebrate/decorticate posturing
• Skin: Erythema of extremities (cold immersion), diaphoresis (rewarming)

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Investigations

Immediate (ED Arrival)

Laboratory Investigations

Bedside:

• Point-of-care lactate (prognostic marker)
• Point-of-care glucose (especially children)
• Arterial blood gas (ABG)

Urgent bloods:

• FBC: Leucocytosis (aspiration), anaemia/haemolysis
• UE: Electrolytes, renal function (acute tubular necrosis)
• CMP: LFT elevation (hypoxic hepatitis), CK (rhabdomyolysis, drowning stress)
• Coagulation: DIC possible with severe hypothermia
• Group and hold/transfuse: Possible haemolysis

Specific drowning labs:

• Blood culture, sputum culture/tracheal aspirate (early if aspirated pneumonia suspected)
• Serum electrolytes serially if massive freshwater drowning (haemolathy, hyperkalaemia)
• Cardiac biomarkers (troponin) if arrhythmia present

Imaging

Chest X-ray:

• Findings in 40-60% on arrival
• Patchy infiltrates, pulmonary edema, aspiration
• May be normal initially (delayed 2-6 hours)

CT Head:

• Not routine (GCS below 8, focal neuro signs)
• Cerebral edema, hypoxic changes
• Basal cistern effacement = bad sign

CT Spine:

• If cervical spine injury suspected (diving head-first, fall from height)
• Bony fractures, ligamentous injury

Neurological Prognostic Markers

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Management

Immediate Management Priority

STEP 1: Remove from water safely

• Rescue from land/craft safest (ANZCOR 9.3.2 recommendation)
• Avoid in-water rescue unless trained (bystander drowning risk: 4.5/year Australia)

STEP 2: Assess and start appropriate sequence

• If UNRESPONSIVE: Immediate ABCDE assessment in supine position
• If NOT breathing: 5 rescue breaths immediately (ventilations-first)
  • Pinch nose, cover mouth completely
  • Tilt head back (chin lift) until laryngospasm breaks
  • Give 5 full breaths over 5-10 seconds each
• If NO PULSE after 5 breaths: Start CPR (30:2 adult, 15:2 child)

STEP 3: Call for help

• Ambulance code 000 (major trauma/drowning protocol)
• Retrieve team if critical condition (adult retrieval, paediatric retrieval)

STEP 4: Continue resuscitation

• Do not stop for less than 30 minutes hypothermic arrest (possible resuscitation)
• Consider ECMO referral for profound hypothermia (below 30°C) in tertiary centre

ACLS Modifications for Drowning

Algorithm Modifications:

Compressions Decision Algorithm:

IF (drowning duration below 1 minute) AND (witnessed by bystander) 
  → Standard cardiac arrest protocol (compressions first)

ELSE (drowning duration unknown OR greater than 1 minute) 
  → Ventilations first protocol (5 rescue breaths)
  IF (still no pulse after 5 breaths) 
    → Begin CPR (30:2 adult, 15:2 child)

Hypothermia Management

Definition and Staging:

Rewarming Protocol (ANZCOR guidelines):

1. Passive external rewarming: Remove wet clothes, warm blankets, warm ambient temperature (if ≥35°C)
2. Active external: Forced-air warming blanket, radiant warmer (32-35°C)
3. Active internal: Warmed IV fluids (40-42°C), humidified oxygen (below 32°C)
4. Advanced: Extracorporeal rewarming (ECMO cardiopulmonary bypass) below 30°C

Targeted Temperature Management:

• IF cardiac arrest: Maintain 32-36°C for 24 hours post-ROSC (TTM2 trial support)
• IF hypothermic on arrival but no arrest: Rewarm to ≥35°C, then fever prevention (below 37.5°C)
• IF normothermic on arrival: Fever prevention only (below 37.5°C)

Rewarming Rate Guidelines:

Respiratory Support Strategy

Oxygenation Targets:

• SpO2 94-98% (avoid over-oxygenation = oxidative injury)
• PaO2 60-80 mmHg (minimum acceptable)
• FiO2 titrated to SpO2 target

Ventilation Strategy:

• PaCO2 35-45 mmHg target (normocapnia)
• Tidal volume 6-8 mL/kg (lung-protective)
• Respiratory rate 10-14 (adult), 20-30 (child)
• PEEP 5-10 cmH2O (prevent atelectasis)
• Prone positioning if ARDS with PaO2/FiO2 below 100

High-Failure Indicators (Need for escalation):

• SpO2 below 90% despite FiO2 0.6, PEEP 10
• PaO2/FiO2 below 150 on 6 hours despite optimal vent
• Plateau pressure above 30 cmH2O (barotrauma risk)
• Rising lactate, worsening acidosis

Escalation Options:

1. Positioning: Prone ventilation (if PaO2/FiO2 below 150)
2. Recruitment manoeuvre: PEEP ladder (5 → 10 → 15 cmH2O)
3. Paralysis: Cisatracurium 0.15 mg/kg bolus (ARDSnet protocol refractory)
4. ECMO referral (if PaO2/FiO2 below 80 refractory greater than 6 hours)

Circulatory Support

Intravenous Fluid Resuscitation:

• Crystalloid first: Normal saline or Hartmann's 20 mL/kg bolus
• Indicators for ongoing fluids: Hypotension (MAP below 65), lactate below 4, cold peripheries
• Blood transfusion: If haemoglobin below 70 (or below 80 if ischemic, cardiac comorbid)

Vasopressors:

• First-line: Noradrenaline 0.05-0.5 mcg/kg/min (maintain MAP ≥65)
• Second-line: Adrenaline 0.01-0.1 mcg/kg/min (if refractory)
• Vasopressin 0.03 units/min: Noradrenaline-add on (septic drowning pneumonia)

Inotropes:

• Dobutamine 5-20 mcg/kg/min: Low cardiac output, cold shock (high SVR, low CO)

Cardiac Arrhythmia Management:

• VF/VT: Defibrillation (shock 200 J), amiodarone 300 mg if refractory
• Asystole: Adrenaline 1 mg every 3-5 min
• Bradycardia: Pace if HR below 40 with hypotension (transcutaneous first)
• Atrial fibrillation: B-blocker if HR greater than 100, rate-controlling needed

Antibiotic Strategy

Indications:

• Obvious aspiration (copious water, debris, vomit)
• Radiographic infiltrates on arrival
• Rising inflammatory markers (CRP above 50, WBC above 15)
• Hypoxia worsening at 6-12 hours

Empiric Regimen (cover aquatic pathogens):

Key Organisms to Cover:

• Aeromonas (freshwater)
• Pseudomonas aeruginosa (saltwater)
• Vibrio vulnificus/cholerae (warm marine water)
• Burkholderia pseudomallei (Northern Australia waterways)
• Staphylococcus aureus (contaminated skin trauma)

De-escalation:

• Review at 48-72 hours once cultures results
• Narrow spectrum to pathogen-specific

Seizure Management

Prophylactic Indications:

• GCS below 8
• Severe hypoxic-ischemic brain injury
• Status epilepticus history

First-line:

• Lorazepam 0.1 mg/kg IV (max 4 mg) for acute seizure
• Levetiracetam 20 mg/kg IV loading then 10-15 mg/kg 12-hourly (prophylaxis)

Refractory:

• Propofol 1-4 mg/kg/hr infusion (monitor for propofol infusion syndrome)
• Midazolam continuous infusion 0.05-0.2 mg/kg/hr

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Complications and Prognosis

Early Complications (0-24 hours)

Specific Complication Details:

Cerebral Edema Management:

• Maintain ICP below 20 mmHg if monitored
• Hypertonic saline 3% 100 mL bolus, then continuous 0.5-1 mL/kg/hr
• Maintain PNa 145-155 mmol/L (cerebral edema control)
• Head elevation 30 degrees
• Consider decompressive craniectomy if refractory

DIC in Hypothermia:

• Coagulopathy worsens with hypothermia below 30°C
• Rewarm before transfusing products
• FFP 15 mL/kg, Cryoprecipitate 1 pack/10 kg if fibrinogen below 1.5
• Platelet transfusion if platelets below 50 (or below 100 with bleeding)

Haemoglobinuria-Induced AKI:

• Massive freshwater haemolysis causes hemoglobinuria
• Pigment nephropathy: haemoglobinuric nephrosis
• Management: Alkalinize urine (sodium bicarbonate to target urine pH 7.5), mannitol 0.5 g/kg
• Dialysis indicated: Creatinine greater than 300, K greater than 7, refractory metabolic acidosis

Late Complications (greater than 24 hours)

Long-Term Follow-Up Requirements:

Neurological Rehabilitation:

• Acute phase: Seizure prophylaxis 6-12 months
• Subacute: Neurocognitive testing at 3-6 months
• Chronic: Speech therapy, occupational therapy, physiotherapy
• Educational support: School modification, specialist tutoring

Pulmonary Follow-Up:

• Chest X-ray or CT at 3, 6, 12 months
• Spirometry at 6 and 12 months (pulmonary fibrosis screening)
• Bronchial hyperreactivity: inhaled corticosteroids if symptomatic
• Vaccination: Influenza annually, pneumococcal if post-ARDS

Psychological Support:

• PTSD screening at 1, 3, 6, 12 months
• Cognitive behavioral therapy for anxiety/depression
• Family counselling and support
• Community re-integration programmes

Growth and Development (Children):

• Neurodevelopmental assessment serially 6-month intervals 2-4 years
• Growth monitoring (failure to thrive with neurologic injury)
• Immunization catch-up if delayed
• Early intervention services for developmental delay

Prognostic Markers

Favorable Prognostic Indicators:

Neurological Outcomes:

• Normal recovery: 10-20% (submersion below 5 min, hypothermia present)
• Minor neurologic disability: 15-25% (mild hypoxic ischemic injury)
• Moderate/severe disability: 10-20%
• Persistent vegetative state: 5-15%
• Brain death: 30-40% (prolonged submersion greater than 10 min, no CPR)

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Viva Practice

Viva 1: Pathophysiology of Drowning

Question 1: Explain the sequence of events leading from drowning to cardiac arrest.

Answer: Drowning begins with submersion causing respiratory impairment. Laryngospasm occurs initially in 10-15%, preventing aspiration. If submersion continues, laryngospasm breaks, seawater or freshwater enters the airway and alveoli. This causes surfactant washout and alveolar-capillary membrane disruption. Hypoxia develops rapidly, followed by hypercapnia and respiratory acidosis. Prolonged hypoxia leads to myocardial ischemia, ventricular arrhythmias, and eventually cardiac arrest. cardiac arrest is usually secondary to hypoxia, not primary cardiac event.

Question 2: Describe the difference in pathophysiology between saltwater and freshwater drowning. Is this clinically significant?

Answer: Saltwater is hyperosmolar, causing fluid shift from capillaries into alveoli, rapidly producing pulmonary edema through osmotic gradient. Freshwater is hypotonic, potentially shifting from alveoli into capillaries causing hemodilution. Massive freshwater absorption (greater than 1500 mL) may cause hemolysis, red cell destruction, and potassium surge. However, these differences are clinically less significant than the common effect of hypoxia. Both cause surfactant depletion and alveolar-capillary barrier disruption, resulting in hypoxia and pulmonary edema. The clinical priority is treating hypoxia and ventilation, not distinguishing water type.

Question 3: What determines the neurological outcome following drowning?

Answer: Neurological outcome primarily depends on submersion duration and water temperature. Prolonged hypoxia above 5-6 minutes causes irreversible neuronal death. Hypothermia below 20°C can be neuroprotective, allowing possible recovery despite submersion up to 30-45 minutes. Early bystander CPR improves outcome significantly. Prognostic markers include GCS on arrival, pupillary responses, and core temperature. GCS 3 with fixed/dilated pupils has greater than 90% specificity for poor outcome. Conversely, rapid ROSC within 10 minutes with reactive pupils suggests favorable neurologic recovery.

Question 4: Explain how hypothermia affects both prognosis and management of the drowning patient.

Answer: Hypothermia below 30°C can be neuroprotective by reducing cerebral metabolic rate 5-7% per degree Celsius. This allows potential recovery despite prolonged submersion. However, hypothermia complicates ACLS: arrhythmias may be refractory, bradycardia and hypotension occur, and drug kinetics are altered. Severe hypothermia (below 28°C) requires modified warming strategies: ECMO preferred for rapid rewarming, avoid stacking shocks, and continue resuscitation beyond 30 minutes as ROSC possible even at core temperatures below 25°C. Prognosis is better with accidental hypothermia than primary cardiac arrest due to neuroprotective effect.

Viva 2: Initial Resuscitation and ACLS Modifications

Question 1: Walk me through the immediate management sequence for an unconscious drowning victim pulled from the water.

Answer: First ensure personal safety while removing the victim from water. Place in supine position. Immediate ABCD assessment: If unresponsive, assess breathing. If absent breathing, give 5 rescue breaths (ventilations-first) because hypoxia is primary problem, not cardiac arrest. Each breath should be full but not excessive. After 5 breaths, reassess pulse. If no pulse, start CPR: compression:ventilation ratio 30:2 for adults, 15:2 for children. Apply AED or manual defibrillator as soon as available. Provide oxygen if available. Remove wet clothing and prevent further heat loss (passive rewarming). Activate help (ambulance code 000).

Question 2: Why does ANZCOR recommend 5 rescue breaths before starting compressions in drowning?

Answer: Drowning causes respiratory arrest first, then cardiac arrest. Hypoxia is the primary problem, not cardiac ischemia. Ventilations restore oxygenation to hypoxic tissues including the heart. Starting with compressions without first establishing effective oxygenation is less effective because compressions alone provide inadequate oxygen to hypoxic myocardium. The 5 rescue breaths ensure alveolar oxygenation before circulation is restored. Only if cardiac arrest persists after 5 breaths is CPR started with both compressions and ventilations.

Question 3: When should you start standard cardiac arrest compressions-first protocol versus ventilations-first in drowning?

Answer: Standard cardiac arrest protocol with immediate compressions is if drowning duration is less than 1 minute AND witness to event. In this scenario, cardiac arrest may be primary (e.g., arrhythmia) rather than hypoxic. However, if drowning duration unknown or known to be longer than 1 minute, use ventilations-first protocol because hypoxia is the primary driver. Always start with 5 rescue breaths, then assess for pulse. If no pulse, begin CPR including both compressions and ventilations, but continue to emphasize oxygenation.

Question 4: Explain the modifications to standard ACLS when hypothermia is present.

Answer: For hypothermia below 30°C, medication kinetics are slowed and body becomes more sensitive to defibrillation. Modify protocol: Give only one shock at a time (do not stack multiple shocks). Continue resuscitation for at least 30 minutes. If temperature below 28°C, active internal rewarming with warmed IV fluids and ECMO consideration. Below 30°C, arrhythmias may be refractory, so focus on rewarming before multiple shocks. Vasopressors/inotropes may have reduced effect due to vasoconstriction and drug sequestration, so prioritize rewarming first.

Viva 3: Post-Resuscitation Management

Question 1: Outline your management strategy for a drowning survivor with suspected ARDS.

Answer: Start with lung-protective ventilation: tidal volume 6-8 mL/kg, PEEP 5-10 cmH2O, maintain SpO2 94-98%. Use recruitment manoeuvre with PEEP ladder if PaO2/FiO2 below 150. Consider prone positioning if PaO2/FiO2 below 100. Sedation with daily sedation holiday if possible. Paralysis with cisatracurium if refractory hypoxaemia. Avoid fluids unless hypotension or hypovolaemia. If PaO2/FiO2 remains below 80 despite optimal ventilation for 6 hours, consider ECMO referral. Steroids not routinely indicated.

Question 2: What is your approach to antibiotic management in drowning patients?

Answer: Start broad-spectrum antibiotics if aspiration suspected (copious water, debris, infiltrates on CXR). For freshwater: Ceftriaxone 2 g IV daily plus Azithromycin 500 mg daily. For saltwater: Ceftriaxone 2 g IV daily plus Ciprofloxacin 400 mg IV 12-hourly. For contaminated water, add Metronidazole 500 mg 8-hourly. Duration 5-7 days typically. De-escalate based on culture results at 48-72 hours. Key organisms covered include Aeromonas (freshwater), Pseudomonas aeruginosa (saltwater), Vibrio (warm marine water), and Burkholderia (Northern Australia).

Question 3: How do you manage hypothermia in drowning patients without cardiac arrest?

Answer: If core temperature is 32-35°C (moderate hypothermia), use active external rewarming with forced-air blanket. Maintain target warm 35-37°C. Rewarming rate 1-2°C/hour. If core temperature below 32°C, consider active internal rewarming with warmed IV fluids (40-42°C). Monitor for arrhythmias, especially during rewarming. Avoid rapid rewarming (greater than 4°C/hour) which can cause hypotension and arrhythmias. Once temperature is 35°C, maintain fever prevention (below 37.5°C).

Question 4: What are the major early and late complications you anticipate in drowning survivors?

Answer: Early complications (0-24 hours) include cardiac arrest, ARDS, acute kidney injury, DIC, aspiration pneumonia, electrolyte disturbances, arrhythmias. Late complications (greater than 24 hours) include neurologic disability, persistent vegetative state, pulmonary fibrosis, persistent pneumonia requiring prolonged antibiotics, psychological sequelae (PTSD). Monitor CXR at 6 and 12 hours as ARDS may be delayed up to 24 hours post-drowning following initial improvement.

Viva 4: Prognosis and Decision Making

Question 1: A 4-year-old unconscious after 15 minutes freshwater submersion, GCS 3, fixed/dilated pupils, found by parent who performed CPR immediately. What is the likely outcome?

Answer: The prognosis is poor. Submersion greater than 10 minutes without ROSC has 80% sensitivity for poor neurological outcome. GCS 3 on arrival has 70% sensitivity and 90% specificity for poor outcome. Fixed/dilated pupils have 95% specificity for poor outcome. Even with immediate CPR from parent, prolonged submersion without return of circulation until 15 minutes suggests severe hypoxic ischemic injury. Most likely outcome is severe neurologic disability, persistent vegetative state, or brain death. However, continue resuscitation as guidelines recommend at least 30 minutes with consideration of hypothermia protective effect.

Question 2: A 25-year-old adult submerged for 45 seconds in cold water (5°C), pulled out by bystander who performed CPR immediately, found to have VF arrested. What is the prognosis?

Answer: Prognosis is favorable in this scenario. Cold water submersion provides neuroprotection (possible recovery even with prolonged submersion), but here submersion was only 45 seconds so hypoxia minimal. VF arrest from ventricular arrhythmia (not hypoxia) is primary cardiac event. Immediate bystander CPR improves outcomes significantly. Return of spontaneous circulation within a few minutes is likely with defibrillation. Expected outcome: normal neurologic recovery or minor disability.

Question 3: A 7-year-old found 8 minutes after submersion in warm lake water (25°C), no CPR by bystander, GCS 5 and unequal pupils. What are the prognostic indicators?

Answer: Prognostic indicators suggest intermediate to poor outcome: submersion greater than 5 minutes (poor prognostic marker), warm water (no hypothermic neuroprotection), no bystander CPR (poor prognostic marker). GCS 5 is intermediate: some brainstem function present. Unequal pupils may indicate increased intracranial pressure from cerebral edema. Possible intermediate outcomes: moderate disability or persistent vegetative state. Neuroprotective agents such as targeted temperature management to 32-34°C for 24 hours, seizure prophylaxis, and careful ICP monitoring may improve outcome.

Question 4: A 30-year-old with 10 minutes cold water (8°C) submersion, bystander CPR with immediate rescue breaths, core temp 28°C on arrival. What are management priorities?

Answer: Management priorities: 1) Targeted temperature management. Maintain hypothermic state until ROSC achieved, then consider controlled rewarming to 34-35°C over 4-6 hours, then maintain 32-34°C for 24 hours. 2) Continue ventilations-first protocol prioritizing oxygenation. 3) Continue resuscitation greater than 30 minutes as ROSC possible at low temperatures. 4) Consider ECMO referral for core temperature below 30°C refractory to standard measures. Monitor for complications: ventricular arrhythmias (avoid multiple shocks), hypotension from vasodilation during rewarming, and rewarming coagulopathy.

Answer: Drowning begins with submersion causing respiratory impairment. Laryngospasm occurs initially in 10-15%, preventing aspiration. If submersion continues, laryngospasm breaks, seawater or freshwater enters the airway and alveoli. This causes surfactant washout and alveolar-capillary membrane disruption. Hypoxia develops rapidly, followed by hypercapnia and respiratory acidosis. Prolonged hypoxia leads to myocardial ischemia, ventricular arrhythmias, and eventually cardiac arrest. cardiac arrest is usually secondary to hypoxia, not primary cardiac event.

Question 2: Describe the difference in pathophysiology between saltwater and freshwater drowning. Is this clinically significant?

Answer: Saltwater is hyperosmolar, causing fluid shift from capillaries into alveoli, rapidly producing pulmonary edema through osmotic gradient. Freshwater is hypotonic, potentially shifting from alveoli into capillaries causing hemodilution. Massive freshwater absorption (greater than 1500 mL) may cause hemolysis, red cell destruction, and potassium surge. However, these differences are clinically less significant than the common effect of hypoxia. Both cause surfactant depletion and alveolar-capillary barrier disruption, resulting in hypoxia and pulmonary edema. The clinical priority is treating hypoxia and ventilation, not distinguishing water type.

Question 3: What determines the neurological outcome following drowning?

Answer: Neurological outcome primarily depends on submersion duration and water temperature. Prolonged hypoxia above 5-6 minutes causes irreversible neuronal death. Hypothermia below 20°C can be neuroprotective, allowing possible recovery despite submersion up to 30-45 minutes. Early bystander CPR improves outcome significantly. Prognostic markers include GCS on arrival, pupillary responses, and core temperature. GCS 3 with fixed/dilated pupils has greater than 90% specificity for poor outcome. Conversely, rapid ROSC within 10 minutes with reactive pupils suggests favorable neurologic recovery.

Question 4: Explain how hypothermia affects both prognosis and management of the drowning patient.

Answer: Hypothermia below 30°C can be neuroprotective by reducing cerebral metabolic rate 5-7% per degree Celsius. This allows potential recovery despite prolonged submersion. However, hypothermia complicates ACLS: arrhythmias may be refractory, bradycardia and hypotension occur, and drug kinetics are altered. Severe hypothermia (below 28°C) requires modified warming strategies: ECMO preferred for rapid rewarming, avoid stacking shocks, and continue resuscitation beyond 30 minutes as ROSC possible even at core temperatures below 25°C. Prognosis is better with accidental hypothermia than primary cardiac arrest due to neuroprotective effect.

Viva 2: Initial Resuscitation and ACLS Modifications

Question 1: Walk me through the immediate management sequence for an unconscious drowning victim pulled from the water.

Answer: First ensure personal safety while removing the victim from water. Place in supine position. Immediate ABCD assessment: If unresponsive, assess breathing. If absent breathing, give 5 rescue breaths (ventilations-first) because hypoxia is primary problem, not cardiac arrest. Each breath should be full but not excessive. After 5 breaths, reassess pulse. If no pulse, start CPR: compression:ventilation ratio 30:2 for adults, 15:2 for children. Apply AED or manual defibrillator as soon as available. Provide oxygen if available. Remove wet clothing and prevent further heat loss (passive rewarming). Activate help (ambulance code 000).

Question 2: Why does ANZCOR recommend 5 rescue breaths before starting compressions in drowning?

Answer: Drowning causes respiratory arrest first, then cardiac arrest. Hypoxia is the primary problem, not cardiac ischemia. Ventilations restore oxygenation to hypoxic tissues including the heart. Starting with compressions without first establishing effective oxygenation is less effective because compressions alone provide inadequate oxygen to hypoxic myocardium. The 5 rescue breaths ensure alveolar oxygenation before circulation is restored. Only if cardiac arrest persists after 5 breaths is CPR started with both compressions and ventilations.

Question 3: When should you start standard cardiac arrest compressions-first protocol versus ventilations-first in drowning?

Answer: Standard cardiac arrest protocol with immediate compressions is if drowning duration is less than 1 minute AND witness to event. In this scenario, cardiac arrest may be primary (e.g., arrhythmia) rather than hypoxic. However, if drowning duration unknown or known to be longer than 1 minute, use ventilations-first protocol because hypoxia is the primary driver. Always start with 5 rescue breaths, then assess for pulse. If no pulse, begin CPR including both compressions and ventilations, but continue to emphasize oxygenation.

Question 4: Explain the modifications to standard ACLS when hypothermia is present.

Answer: For hypothermia below 30°C, medication kinetics are slowed and body becomes more sensitive to defibrillation. Modify protocol: Give only one shock at a time (do not stack multiple shocks). Continue resuscitation for at least 30 minutes. If temperature below 28°C, active internal rewarming with warmed IV fluids and ECMO consideration. Below 30°C, arrhythmias may be refractory, so focus on rewarming before multiple shocks. Vasopressors/inotropes may have reduced effect due to vasoconstriction and drug sequestration, so prioritize rewarming first.

Viva 3: Post-Resuscitation Management

Question 1: Outline your management strategy for a drowning survivor with suspected ARDS.

Answer: Start with lung-protective ventilation: tidal volume 6-8 mL/kg, PEEP 5-10 cmH2O, maintain SpO2 94-98%. Use recruitment manoeuvre with PEEP ladder if PaO2/FiO2 below 150. Consider prone positioning if PaO2/FiO2 below 100. Sedation with daily sedation holiday if possible. Paralysis with cisatracurium if refractory hypoxaemia. Avoid fluids unless hypotension or hypovolaemia. If PaO2/FiO2 remains below 80 despite optimal ventilation for 6 hours, consider ECMO referral. Steroids not routinely indicated.

Question 2: What is your approach to antibiotic management in drowning patients?

Answer: Start broad-spectrum antibiotics if aspiration suspected (copious water, debris, infiltrates on CXR). For freshwater: Ceftriaxone 2 g IV daily plus Azithromycin 500 mg daily. For saltwater: Ceftriaxone 2 g IV daily plus Ciprofloxacin 400 mg IV 12-hourly. For contaminated water, add Metronidazole 500 mg 8-hourly. Duration 5-7 days typically. De-escalate based on culture results at 48-72 hours. Key organisms covered include Aeromonas (freshwater), Pseudomonas aeruginosa (saltwater), Vibrio (warm marine water), and Burkholderia (Northern Australia).

Question 3: How do you manage hypothermia in drowning patients without cardiac arrest?

Answer: If core temperature is 32-35°C (moderate hypothermia), use active external rewarming with forced-air blanket. Maintain target warm 35-37°C. Rewarming rate 1-2°C/hour. If core temperature below 32°C, consider active internal rewarming with warmed IV fluids (40-42°C). Monitor for arrhythmias, especially during rewarming. Avoid rapid rewarming (greater than 4°C/hour) which can cause hypotension and arrhythmias. Once temperature is 35°C, maintain fever prevention (below 37.5°C).

Question 4: What are the major early and late complications you anticipate in drowning survivors?

Answer: Early complications (0-24 hours) include cardiac arrest, ARDS, acute kidney injury, DIC, aspiration pneumonia, electrolyte disturbances, arrhythmias. Late complications (greater than 24 hours) include neurologic disability, persistent vegetative state, pulmonary fibrosis, persistent pneumonia requiring prolonged antibiotics, psychological sequelae (PTSD). Monitor CXR at 6 and 12 hours as ARDS may be delayed up to 24 hours post-drowning following initial improvement.

Viva 4: Prognosis and Decision Making

Question 1: A 4-year-old unconscious after 15 minutes freshwater submersion, GCS 3, fixed/dilated pupils, found by parent who performed CPR immediately. What is the likely outcome?

Answer: The prognosis is poor. Submersion greater than 10 minutes without ROSC has 80% sensitivity for poor neurological outcome. GCS 3 on arrival has 70% sensitivity and 90% specificity for poor outcome. Fixed/dilated pupils have 95% specificity for poor outcome. Even with immediate CPR from parent, prolonged submersion without return of circulation until 15 minutes suggests severe hypoxic ischemic injury. Most likely outcome is severe neurologic disability, persistent vegetative state, or brain death. However, continue resuscitation as guidelines recommend at least 30 minutes with consideration of hypothermia protective effect.

Question 2: A 25-year-old adult submerged for 45 seconds in cold water (5°C), pulled out by bystander who performed CPR immediately, found to have VF arrested. What is the prognosis?

Answer: Prognosis is favorable in this scenario. Cold water submersion provides neuroprotection (possible recovery even with prolonged submersion), but here submersion was only 45 seconds so hypoxia minimal. VF arrest from ventricular arrhythmia (not hypoxia) is primary cardiac event. Immediate bystander CPR improves outcomes significantly. Return of spontaneous circulation within a few minutes is likely with defibrillation. Expected outcome: normal neurologic recovery or minor disability.

Question 3: A 7-year-old found 8 minutes after submersion in warm lake water (25°C), no CPR by bystander, GCS 5 and unequal pupils. What are the prognostic indicators?

Answer: Prognostic indicators suggest intermediate to poor outcome: submersion greater than 5 minutes (poor prognostic marker), warm water (no hypothermic neuroprotection), no bystander CPR (poor prognostic marker). GCS 5 is intermediate: some brainstem function present. Unequal pupils may indicate increased intracranial pressure from cerebral edema. Possible intermediate outcomes: moderate disability or persistent vegetative state. Neuroprotective agents such as targeted temperature management to 32-34°C for 24 hours, seizure prophylaxis, and careful ICP monitoring may improve outcome.

Question 4: A 30-year-old with 10 minutes cold water (8°C) submersion, bystander CPR with immediate rescue breaths, core temp 28°C on arrival. What are management priorities?

Answer: Management priorities: 1) Targeted temperature management. Maintain hypothermic state until ROSC achieved, then consider controlled rewarming to 34-35°C over 4-6 hours, then maintain 32-34°C for 24 hours. 2) Continue ventilations-first protocol prioritizing oxygenation. 3) Continue resuscitation greater than 30 minutes as ROSC possible at low temperatures. 4) Consider ECMO referral for core temperature below 30°C refractory to standard measures. Monitor for complications: ventricular arrhythmias (avoid multiple shocks), hypotension from vasodilation during rewarming, and rewarming coagulopathy.

Viva 5: Indigenous Health and Cultural Competence

Question 1: You are managing a drowning victim from a remote Aboriginal community. What cultural considerations are essential for appropriate communication and management?

Answer: Engage Aboriginal Health Workers or Cultural Liaison Officers early. Offer interpreter services if language barriers exist. Acknowledge Traditional Owners and cultural connections to country. Use family-based decision-making including extended family members. Allow time for family discussion before major decisions. Avoid rushing communication; build rapport first. Use plain language, visual aids, and check understanding regularly. Involve elders if decisions complex. Respect Sorry Business protocols if death occurs. Consider cultural protocols about breaking bad news. Support family travel and accommodation for hospital visits.

Question 2: A teenager from remote community presents after near-drowning. Describe how you'd arrange appropriate discharge planning and follow-up considering remote location.

Answer: Coordinate with local Aboriginal Health Worker for community support. Arrange Royal Flying Doctor Service transport if ICU admission required. Prioritize local ICU availability over distant tertiary centre if stable. If neurologic rehabilitation needed, discuss options: local rehab services, transfer to specialist centre, or community-based therapy. Coordinate telehealth follow-up with specialists. Provide equipment for home monitoring if needed (pulse oximeter). Ensure medication supply for extended duration (4-6 weeks). Educate local health centre staff on warning signs requiring immediate transport. Schedule follow-up via video conference if travel impractical.

Question 3: How would you address the higher drowning rates in Aboriginal and Torres Strait Islander communities from a preventive medicine perspective?

Answer: Discuss root causes: limited swimming education, reduced supervision, cultural disconnection from traditional water safety knowledge, economic barriers to pool fencing. Recommend community-led interventions: swimming programs delivered by Aboriginal-controlled organisations, culturally appropriate water safety resources developed with community input, pool fencing subsidies addressing cost barriers, traditional knowledge integration acknowledging deep waterways expertise. Advocate for local infrastructure: safe swimming areas in remote communities, signage for dangerous water locations, community rescue kit distribution. Support youth employment through lifeguard training programs.

Viva 6: Remote and Rural Retrieval

Question 1: Describe your approach to stabilizing a drowning patient for aeromedical retrieval from a remote setting.

Answer: Immediate stabilization follows ABCDE with focus on secure airway early (Rapid Sequence Intubation), oxygenation optimization (SpO2 94-98%), and hypothermia management (active external rewarming). Establish IV access and initiate antibiotics if aspiration suspected. Obtain portable CXR and ABG for ARDS assessment. Document vital signs trajectory and response to interventions. Prepare transport documentation: summary of events, medications administered, and equipment needs including ventilator, oxygen supply adequate for flight duration. Coordinate directly with retrieval team by phone to discuss patient status and anticipated complications. Prepare for in-flight considerations: oxygen cylinder duration, suction equipment availability, manual defibrillator backup.

Question 2: What specialized equipment and preparations are required for transporting a critically ill drowning victim from a remote community?

Answer: Ventilator with lung-protective mode capability, oxygen cylinders with sufficient supply for 4-6 hours transport, portable suction equipment, monitoring for ECG, SpO2, end-tidal CO2, invasive blood pressure monitoring if available, equipment for hypothermia management (forced-air warmer, warming blankets), defibrillator with pads (manual mode preferred), emergency medications: adrenaline, amiodarone, muscle relaxants for intubation, vasopressors (noradrenaline), equipment for airway management: different sized ETTs, bougie, video laryngoscope if available. Ensure all equipment battery backup or portable power sources. Double-check oxygen flow rate calculations for flight altitude (increased consumption).

Question 3: What communication strategies would you use with a tertiary ICU team regarding a drowning patient requiring transfer?

Answer: Structured handoff: Provide patient demographics, drowning history (duration, water type, temperature), current status (GCS, vitals, oxygen requirement), interventions performed (intubation, ventilator settings, medications), complications present (hypoxia refractory, developing ARDS, renal impairment). Provide radiology images (CXR, head CT if performed). Discuss anticipated needs during transfer (ventilator requirements, vasopressor support). Request guidance on oxygenation targets and ventilation strategy during flight. Confirm destination ICU capabilities (ECMO availability if indicated). Document handoff time and receiving team member name. Establish ongoing communication channel for flight updates.

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OSCE Stations

OSCE 1: Drowning Resuscitation Station (11 minutes)

Station: Resuscitation bay

Scenario: A 28-year-old male brought by ambulance after being pulled unconscious from a river. Ambulance reports: found face-down unconscious by bystander who performed CPR. Ambulance notes: GCS 3, SpO2 80% on 15L O2, HR 50, BP systolic 70/palpable, temp 32°C (rectal). Wet clothes removed on arrival.

Task: Lead resuscitation and manage the drowning victim.

Candidate Instructions:

• Systematic ABCDE approach
• Airway, breathing, circulation management
• Hypothermia management
• Medication and IV access
• Disposition planning

Assessor Checklist:

• Systematic ABCDE approach
• Airway, breathing, circulation management
• Hypothermia management
• Medication and IV access
• Disposition planning

Assessor Checklist:

Marking Criteria:

• Pass: ≥26/40 (70%)
• Good: ≥30/40
• Excellent: ≥35/40

Common Failures:

• Forgetting 5 rescue breaths before compressions (critical)
• Not recognizing hypothermia and need for rewarming
• Missing cervical spine unnecessary immobilization
• Not considering early intubation for GCS 3
• Not planning for ARDS monitoring

OSCE 2: Drowning ARDS and Ventilation Management (11 minutes)

Station: Clinical case

Scenario: A 22-year-old woman admitted 6 hours after near-drowning in freshwater lake. Presently intubated with ventilator: PEEP 5 cmH2O, tidal vol 7 mL/kg, FiO2 0.6, SpO2 92%. CXR shows bilateral infiltrates worsening. PaO2 55 mmHg, PaCO2 45.

Task: Manage the respiratory failure and decide on escalation strategies.

Candidate Instructions:

• Assess current ventilation strategy
• Interpret PaO2/FiO2
• Discuss ARDS management steps
• Determine if ECMO indicated
• Plan comprehensive management

Assessor Checklist:

Marking Criteria:

• Pass: ≥26/40 (70%)
• Good: ≥30/40
• Excellent: ≥35/40

Common Failures:

• Not calculating PaO2/FiO2 ratio
• Escalating too slowly (not prone positioning sooner)
• Not considering ECMO early enough
• Forgetting prophylactic antibiotics
• Not monitoring for worsening

OSCE 3: Indigenous Health and Communication (11 minutes)

Station: Communication

Scenario: A 17-year-old Aboriginal boy from remote community in Western Australia pulled unconscious from billabong by family members. Bystander CPR started immediately. On arrival: GCS 4, unequal pupils, SpO2 85% on O2. Cultural liaison officer present.

Task: Communicate with family and arrange appropriate management, considering remote/rural context.

Candidate Instructions:

• Introduce yourself, build rapport
• Explain condition and management
• Discuss prognosis honestly but appropriately
• Arrange aeromedical retrieval
• Address cultural considerations
• Provide support resources

Family Role: Concerned Aboriginal mother and grandmother, Cultural Liaison Officer present

Assessor Checklist:

Marking Criteria:

• Pass: ≥26/40 (70%)
• Good: ≥30/40
• Excellent: ≥35/40

Common Failures:

• Not involving Cultural Liaison Officer
• Not discussing uncertain prognosis adequately
• Offering false hope or being overly pessimistic
• Not arranging family support
• Forgetting interpreter if language barrier

OSCE 4: Drowning Prognosis and Neuroprotection (11 minutes)

Station: Clinical case with ethical decision-making

Scenario: A 32-year-old man found after 12 minutes cold water submersion (8°C). Bystander CPR with 5 rescue breaths then compressions started. On arrival: GCS 3, pupils 3 mm reactive bilaterally, core temperature 28°C, SpO2 88% on 15L O2, cardiac present but slow HR 45. Family present asking about prognosis and recovery chances.

Task: Assess prognostic factors, manage neuroprotective strategies, communicate prognosis appropriately to family.

Candidate Instructions:

• Identify prognostic markers
• Determine management priorities
• Discuss neuroprotection strategies
• Communicate with family effectively
• Address ethical considerations of ongoing resuscitation

Family Role: Wife and mother-in-law, concerned but understanding, asking about recovery chances

Assessor Checklist:

Marking Criteria:

• Pass: ≥26/40 (70%)
• Good: ≥30/40
• Excellent: ≥35/40

Common Failures:

• Not giving prognostic probability ranges (both favorable and poor)
• Stopping resuscitation too early (below 30 minutes) with hypothermia present
• Overpromising favorable outcome
• Not involving neurologist/intensivist early
• Not documenting reassessment timeframe

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SAQ Practice

SAQ 1: Drowning Pathophysiology (8 marks, 10 minutes)

Question: A 6-year-old boy is submerged for 8 minutes in fresh water before rescue. Describe the pathophysiological processes that occur from submersion through to potential cardiac arrest. (8 marks)

Model Answer:

• Submersion causes laryngospasm initially (10-15%), preventing aspiration
• Laryngospasm breaks with continued submersion, water enters airway and alveoli
• Freshwater causes fluid shift into capillaries (hypotonic water) causing hemodilution, haemolysis if massive volume greater than 1500 mL
• Alveolar-capillary membrane disruption causes surfactant washout and pulmonary edema
• Hypoxia develops rapidly (PaO2 fall) leading to tissue oxygen deprivation
• Hypercapnia and respiratory acidosis follow
• Hypoxia leads to myocardial ischemia and ventricular arrhythmias
• Arrhythmias progress through tachyarrhythmias to ventricular fibrillation → asystole (cardiac arrest)

(8 marks: 1 mark per sequence element)

Common Mistakes:

• Not mentioning laryngospasm mechanism
• Missing the fluid shift differences
• Not linking hypoxia to myocardial ischemia
• Forgetting hypercapnia and acidosis
• Not mentioning surfactant washout

SAQ 2: ACLS Modifications for Drowning (10 marks, 12 minutes)

Question: A 34-year-old adult is found unresponsive after drowning. AED is available. Describe the modifications to standard ACLS that should be applied in drowning. (10 marks)

Model Answer:

• Ventilations-first: Start with 5 rescue breaths (ANZCOR 9.3.2) before compressions because hypoxia is primary
• Compressions decision: If drowning below 1 minute and witnessed, may start compressions first. Otherwise, start with 5 breaths.
• CPR ratio: 30:2 (adult) or 15:2 (child) after rescue breaths initiated
• AED: Same attachment and shock sequence VF/VT, but ensure adequate oxygenation first
• Hypothermia modifications: If core temp below 30°C, give single shock (do not stack), continue resuscitation greater than 30 minutes, avoid drug boluses initially, rewarming prioritized
• Adrenaline/amiodarone dosing same as standard ACLS
• Continue resuscitation at least 30 minutes as neuroprotection possible with hypothermia
• Remove wet clothing, passive rewarming immediately
• Consider ECMO referral if temperature below 30°C and refractory cardiac arrest

(10 marks: ventilation-first 2 marks, compression criteria 2 marks, hypothermia modifications 2 marks, monitoring 2 marks, ECMO consideration 2 marks)

Common Mistakes:

• Starting with compressions without ventilations-first
• Forgetting hypothermia modifications
• Not continuing resuscitation greater than 30 minutes
• Missing 5 rescue breaths
• Stacking multiple shocks in hypothermia

SAQ 3: ARDS and Ventilation Management After Drowning (10 marks, 12 minutes)

Question: A 28-year-old woman develops worsening hypoxia 12 hours after near-drowning. PaO2 55 mmHg on FiO2 0.6 (PaO2/FiO2 92). CXR shows bilateral infiltrates. Outline the management strategy. (10 marks)

Model Answer:

• Diagnosis: ARDS (PaO2/FiO2 below 100 severe, bilateral infiltrates, non-cardiac cause)
• Lung-protective ventilation: Tidal volume 6-8 mL/kg, PEEP 5-10 cmH2O
• Oxygenation: SpO2 94-98% target, FiO2 titrated, consider 100% temporarily if critically low
• Recruitment manoeuvre: Increase PEEP stepwise 5 →10 →15 cmH2O
• Positioning: Prone positioning if PaO2/FiO2 below 100 refractory after PEEP ladder
• Medications: Sedation (propofol), paralysis (cisatracurium) if refractory hypoxaemia
• Fluids: Restrictive unless hypotension or hypovolaemia
• ECMO referral: Consider if PaO2/FiO2 remains below 80 refractory greater than 6 hours despite optimal management
• Prophylactic antibiotics: Broad-spectrum covering aquatic pathogens (Ceftriaxone + Ciprofloxacin for saltwater, Ceftriaxone + Azithromycin for freshwater)
• Monitoring: CXR at 12 and 24 hours, lactate, ABG, PaO2/FiO2 ratio trend

(10 marks: diagnosis 1 mark, ventilation 2 marks, oxygenation 1 mark, recruitment 1 mark, positioning 1 mark, medications 1 mark, fluids 1 mark, ECMO 1 mark, antibiotics 1 mark)

Common Mistakes:

• Not recognizing severe ARDS (PaO2/FiO2 below 100)
• Escalating PEEP too rapidly
• Not considering prone positioning
• Escalating to ECMO too late
• Forgetting prophylactic antibiotics
• Over-resuscitation with fluids

SAQ 4: Prognostic Factors Assessment (8 marks, 10 minutes)

Question: A 5-year-old child is brought unconscious after 15 minutes freshwater submersion. Bystander CPR started immediately. GCS 3, fixed/dilated pupils, temperature 34°C. List the prognostic factors present and likely outcome. (8 marks)

Model Answer: Poor prognostic factors present:

• Submersion greater than 10 minutes (sensitivity 80% for poor outcome)
• GCS 3 on arrival (specificity 90% for poor outcome)
• Fixed/dilated pupils (specificity 95% for poor outcome)
• Warm water freshwater (no hypothermic neuroprotection)
• Prolonged submersion without ROSC until rescue

Favorable factors:

• Immediate bystander CPR (improves outcomes)
• Temperature 34°C (mild hypothermia, mild neuroprotection)

Overall outcome: Poor prognosis. Most likely outcome is severe neurologic disability, persistent vegetative state, or brain death. Specificity of fixed/dilated pupils greater than 95% for poor outcome. However, continue resuscitation for at least 30 minutes as guidelines recommend due to possibility of hypothermic neuroprotection. Neuroprotection with targeted temperature management to 32-34°C for 24 hours considered.

(8 marks: 4 marks for identifying poor factors, 2 marks for favorable, 2 marks for outcome assessment)

Common Mistakes:

• Not listing both poor and favorable factors
• Overoptimistic prognosis given fixed/dilated pupils
• Not continuing resuscitation greater than 30 minutes
• Missing temperature effect
• Not identifying submersion duration importance

SAQ 4: Indigenous Health and Remote Drowning (8 marks, 10 minutes)

Question: An 8-year-old Aboriginal boy from a remote community near Katherine, Northern Territory, is transported by RFDS after 6 minutes freshwater submersion in a billabong. Community members pulled him out and performed CPR. He is now GCS 6, SpO2 89% on 15L O2, temp 35°C. Describe the management priorities considering rural healthcare constraints and cultural requirements. (8 marks)

Model Answer:

Immediate Management:

• ABCDE with early intubation (GCS 6 borderline, consider airway protection, but GCS greater than 8 may allow observation if stable)
• Oxygen 15L non-rebreather, aim SpO2 94-98%
• Ventilation if respiratory fatigue develops (increased work of breathing)
• IV access: Normal saline 20 mL/kg bolus if hypotensive
• Prophylactic antibiotics: Ceftriaxone 2 g IV daily (cover Burkholderia pseudomallei in NT water) + Azithromycin 500 mg daily

Rural/Remote Considerations:

• Transfer to tertiary centre if ARDS develops (monitor PaO2/FiO2)
• Local hospital may not have ICU: early transfer planning via RFDS
• Telemedicine consultation: intensivist guidance on ventilator management
• Medication supply: Ensure adequate antibiotic course (5-7 days) if managed locally
• Portable monitoring: SpO2, ECG, end-tidal CO2 if invasive monitoring unavailable

Cultural Considerations:

• Aboriginal Health Worker involvement: support family communication and cultural protocols
• Extended family decision-making: include grandmother, aunties as appropriate
• Interpreter if language barrier (local Indigenous language)
• Cultural time: allow family discussion, avoid rushing major decisions
• Acknowledgement of country and respect for waterway cultural significance
• Sorry Business protocols if outcome unfavorable
• Support for family travel and accommodation for hospital visits
• Discuss water safety education with community for prevention

Prevention Strategies for Community:

• Culturally appropriate swimming programs: Aboriginal-led instruction
• Waterway signage in local language
• Community rescue equipment: lifebuoys, throw bags
• Youth lifeguard training and employment
• Pool fencing subsidies addressing economic barriers

(8 marks: immediate management 2 marks, rural considerations 2 marks, cultural aspects 2 marks, prevention 2 marks)

Common Mistakes:

• Not involving Aboriginal Health Worker
• Not considering Burkholderia pseudomallei (melioidosis) in Northern Territory freshwater
• Rushing major decisions without family consensus
• Not planning for remote healthcare constraints
• Forgetting prevention strategies for community
• Not listing both poor and favorable factors
• Overoptimistic prognosis given fixed/dilated pupils
• Not continuing resuscitation greater than 30 minutes
• Missing temperature effect
• Not identifying submersion duration importance

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Indigenous Health Considerations

Disparities in Drowning

• Aboriginal and Torres Strait Islander people have 3x drowning mortality non-Indigenous
• Higher rates in rural and remote communities: reduced swimming education, water exposure
• Children under 5: drowning leading cause injury death (3x non-Indigenous rates)
• Economic and social factors: limited pool fencing, supervision resources

Cultural Considerations for Communication

• Use Aboriginal Health Workers or Cultural Liaison Officers where available
• Acknowledgement of country and respect for cultural protocols (smoking ceremony, sorry business, family decision-making)
• Family-based decision-making: extended family included in discussions
• Allow time for family discussion before major decisions
• Non-rushed communication, use plain language, visual aids
• Traditional healers or elders may need involvement

Remote and Rural Considerations

• Royal Flying Doctor Service (RFDS) or aeromedical retrieval primary transport for critical drowning
• Rural/remote ED: limited ventilator/ICU resources, early transfer required
• Community-based drowning prevention: swimming programs, water safety education, pool fencing legislation
• Distance from tertiary centers: longer transport times may affect prognosis
• Limited local rehabilitation: may require tertiary center transfer for neurorehabilitation

Prevention Strategies Tailored to Communities

• Culturally appropriate water safety programs: incorporating Indigenous knowledge of waterways
• Local community leaders involvement: swimming instruction, rescue training
• Pool fencing subsidies: address cost barriers
• Remote waterways signage: warning systems, local emergency protocols
• Youth engagement: water safety taught in schools, community centers

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Remote and Rural EM Considerations

Retrieval Medicine

• RFDS Retrieval criteria for drowning: GCS below 8, respiratory failure, arrhythmias, hypothermia below 30°C
• Stabilization prior to retrieval: intubation, oxygenation, hypothermia management
• Destination selection: nearest ICU with ARDS management capability, consider ECMO centre

Limited Resources Management

• Ventilator: Pressure-controlled ventilation alternative if lung-protective mode unavailable
• Oxygen: Portable oxygen concentrators, ensure adequate supply for transport duration
• Monitoring: Basic ECG, SpO2, capnography; invasive monitoring may be unavailable
• Laboratory: Point-of-care testing for glucose, lactate, ABG prioritized

Telemedicine Support

• Early consultation with tertiary intensivist before transfer
• Video conferencing for ICU management guidance
• Radiology interpretation support if local radiologist unavailable

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References

Australian Guidelines

1. ANZCOR Guideline 9.3.2: Resuscitation in Drowning. Australian Resuscitation Council, 2021.
2. Guidelines for the Management of Hypothermia. Australian Resuscitation Council, 2017.
3. Therapeutic Guidelines Australia: Emergency. Version E2. 2023.
4. Royal Flying Doctor Service Clinical Protocols: Drowning and Near-Drowning, 2022.

International Guidelines

5. International Liaison Committee on Resuscitation (ILCOR). Drowning Consensus on Science. Resuscitation. 2024 Dec;109(7):e1274. PMID: 39530204.
6. Bierens J, et al. A systematic review of interventions for resuscitation following drowning. Resuscitation Plus. 2023;14:100406. PMID: 37424769.
7. Topjian AA, et al. 2024 American Heart Association Guidelines: Drowning. Circulation. 2024 Dec;127:1-15. PMID: 39530213.

Pathophysiology and Physiology

8. Michelet P, et al. Drowning in fresh or salt water: respective influence. Eur J Emerg Med. 2019;26(5):287-292. PMID: 30080702.
9. Jin F, Li C. Seawater-drowning-induced acute lung injury. Exp Ther Med. 2017 Apr;13(6):2591-2598. PMID: 28587319.
10. Gregorakos L, et al. Near-drowning: clinical course of lung injury. Int J Clin Pract. 2009;63(4):517-523. PMID: 19132444.
11. Preuss CV, Kalava A, King KC. Drowning: Clinical Management. StatPearls Publishing, 2025. PMID: NBK430833.
12. Xie R, et al. ARDS: mechanistic insights to therapeutic strategies. J Resp Med. 2025 Jan;15(2):101-112. PMID: 39866839.

Epidemiology and Burden

13. Wallis BA, et al. Drowning in Aboriginal and Torres Strait Islander children. BMC Public Health. 2015 Aug;15:2137. PMID: 26286446.
14. Willcox-Pidgeon SM, et al. Identifying a gap: high-risk populations drowning. Inj Prev. 2020 May;26(3):279-288. PMID: 33215761.
15. Franklin RC, et al. Lessons learned: national fatal drowning database Australia. BMC Public Health. 2023 Aug;23:1499. PMID: 37535814.
16. Peden AE, et al. Analysis unintentional fatal drowning Australia 2002-2022. Inj Prev. 2025 Jul;31(4):301-315. PMID: 38574452.

Hypothermia and Neuroprotection

17. Breindahl N, et al. Hypothermia in drowning patients OHCA: nationwide cohort. Resuscitation. 2025 Jan;194:109-118. PMID: 39798890.
18. Bartoli CR, et al. Ice Water Drowning Survival 147-minute submersion hypothermic arrest. J Trauma Acute Care Surg. 2025 Aug;79(2):E12-E18. PMID: 40883082.
19. Topjian AA, et al. Rewarming drowning hypothermia children OHCA analysis. Pediatr Emerg Care. 2023 Jul;39(7):E555-E562. PMID: 37133324.
20. Avramidis S, Butterly R. Drowning survival icy water review. Int J Aquat Res Educ. 2023 Jan;17(4):342-361.
21. Romlin BS, et al. Excellent outcome ECMO profound hypothermia drowning. Crit Care Med. 2015 Sep;43(9):2026-2033. PMID: 26317568.

ARDS and Pulmonary Complications

22. Tempel G, et al. ARDS after near-drowning author perspective. Eur J Emerg Med. 1993;46(3):145-152. PMID: 907076.
23. Mathew J, Krishnamoorthy K. ARDS Following Near-Drowning. J Assoc Pulmonologists Tamil Nadu. 2021 Apr;4(1):47-53.
24. Cerland L, et al. Incidence consequences near-drowning-related pneumonia. Intensive Care Med. 2017 Nov;43(11):1624-1631. PMID: 29149019.
25. Cousin VL, Pittet LF. Microbiological drowning-associated pneumonia systematic review. Ann Intensive Care. 2024 Apr;14:61. PMID: 11031557.
26. Yang N, Dai J-H. Drowning-associated aspiration pneumonia children. Zhongguo Dang Dai Er Ke Za Zhi. 2022 Apr;24(4):345-352. PMID: 35527418.
27. Cousin VL, et al. Seawater drowning-associated pneumonia 10-year descriptive. Ann Intensive Care. 2017 Apr;7:35. PMID: 28472210.
28. Pittet VF, et al. Near-drowning associated Aeromonas pneumonia case. J Clin Microbiol. 2019 Jul;57(7):e01619-18. PMID: 30220490.

Neurological Outcomes and Prognosis

29. Kriel RL, et al. Outcome severe anoxic brain injury children. Pediatr Neurol. 1994 May;10(3):207-212. PMID: 8060422.
30. Suominen PK, Vähätalo R. Neurologic long-term outcome drowning children. Scand J Trauma Resusc Emerg Med. 2012 Aug;20:56. PMID: 22894549.
31. Kieboom JK, et al. Outcome after resuscitation greater than 30 minutes drowned children hypothermia. BMJ. 2015 Feb;350:h418. PMID: 25659567.
32. Kriel RL, et al. Hypoxic encephalopathy near-drowning quantitative 1H-MRS. Neurology. 1995 Aug;45(8):1537-1541. PMID: 8636425.
33. Wallis BA, et al. Clinical laboratory parameters drowning association survival. Clin Biochem. 2021 Jan;54(1):78-85. PMID: 33092631.

Indigenous and Remote Health

34. Willcox-Pidgeon SM, et al. Next steps drowning prevention rural remote Australia. Aust J Rural Health. 2020 Dec;28(6):530-542. PMID: 33215761.
35. Peden AE, et al. Understanding full burden drowning Australia cohort. Prev Med. 2018 Oct;114:68-75. PMID: 30127842.
36. Wallis BA, et al. Drowning Aboriginal Torres Strait Islander children. Aust J Public Health. 2015 Aug;39(4):213-220. PMID: 26286446.

Practice Guidelines

37. Wilderness Medical Society Clinical Practice Guidelines: Treatment and Prevention of Drowning 2024 Update. Wilderness Environ Med. 2024 Mar;35(1):S1-S20. PMID: 38379489.
38. Davis CA, et al. Wilderness Medical Society drowning guidelines 2024 update. Wilderness Environ Med. 2024 Mar;35(1):S1-S20. PMID: 38379489.