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NEAR DROWNING. Pediatric Critical Care Medicine Emory University Children’s Healthcare of Atlanta. Objectives. Definition Incidence, epidemiology, causes Prognosis Interventions/managements Opportunities that impact outcome. Definition.
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NEAR DROWNING Pediatric Critical Care Medicine Emory University Children’s Healthcare of Atlanta
Objectives • Definition • Incidence, epidemiology, causes • Prognosis • Interventions/managements • Opportunities that impact outcome
Definition • Drowning: die within 24 hours of a submersion incident • Near Drowning: survive at least 24 hrsafter a submersion incident • 2002 World Congress: all victims to be labeled as drowning
Incidence/Epidemiology • CDC 2012 for 2005-2009 for US • ~3,880 fatal drowning, 2X treated in ER for non-fatal drowning • Leading cause of injury death among children 1-4 yrs, highest rate • 2nd leading cause of all accidental deaths <14 yr (MVC 1st) • Fatality: male>female (42.07:0.54/100,000 • African-American • 1.3X higher than Caucasian • 3.4X higher in 5-14 yo age group
Incidence • For every 1 death • 4 others hospitalized a • 14 seen in the ER • incidence: holidays, weekends and warm weather • Children <5 pools; older kids and adults in open water • Fatality: 35%; 33% with neurological impairment; 11% severe neurologic sequelae
Causes • Toddlers: • Lapse of supervision • Afternoon/early evening-meal time • 84% with responsible supervising adults • Only 18% of cases actually witnessed
Causes • Recreational boating • 90% of deaths due to drowning • Vast majority are not wearing life jackets • 1,200/yr • Small, open boats • 20% of deaths • Too few or no floatation devices! • Diving • 700-800/yr • 1st drive in unfamiliar water • 40-50% alcohol related
Causes • Spas, hot tubs • Entrapment in drains, covers • Buckets drowning • males/>females • African-Americans>caucasians • Warm months>cold
Causes • Epilepsy: • 1.5-4.6 % had pre-existing seizure disorder • >5 yr, drown in bathtub, not be supervised • Long QT syndrome: • Swimming may be a trigger for LQTS • Near drowning may be first presentation • Specific gene KVLQT1 mutation associated w/swimming trigger & submersion
aspiration of water (90%) Laryngospasm aborted Aspiration & Laryngospasm Swallows water Unexpected Submersion anoxia, seizures and death without aspiration (10%) Laryngospasm recurs Stage I (0-2 minutes) Stage II (1-2 minutes) Stage III
Pathophysiology • Part I • Voluntary breath-holding • Aspiration of small amounts into larynx • Involuntary laryngospasm • Swallow large amounts • Laryngospasm abates (due to hypoxia) • Aspiration into lungs
Pathophysiology • Part II • Decrease in sats • Decrease in cardiac output • Intense peripheral vasoconstriction • Hypothermia • Bradycardia • Circulatory arrest, while VF rare • Extravascular fluid shifts, diuresis
Pathophysiology • Diving reflex • Bradycardia, apnea, vasoconstriction • Relatively quite weak in humans • better in kids • Occurs when the face is submerged in very cold water (<20°C) • Extent of neurologic protection in humans due to diving reflex is likely very minimal
Pathophysiology • Asphyxia, hypoxemia, hypercarbia, & metabolic acidosis • Fresh water vs salt water - little difference (except for drowning in water with very high mineral content, like the Dead Sea) • Hypoxemia • Occlusion of airways with water & particulate debris • Changes in surfactant activity • Bronchospasm • Right-to-left shunting increased • Physiologic dead space increased
Pathophysiology • Cardiac arrhythmias • Hypoxic encephalopathy • Renal insufficiency • Pulmonary injury • Global brain anoxia & potential diffuse cerebral edema
Pathophysiology – Cerebral edema • Initial hypoxia • Post resuscitation cerebral hypoperfusion • Increased ICP • Cytoxic cerebral edema: • BBB remains intact: derangement in cellular metabolism resulting in inadequate functioning of the Na & K pump • Excessive accumulation of cytosolic calcium causing cerebral arterial spasm • Lance-Adams syndrome – with sign hypoxia • Post hypoxic (action) myoclonus, often mistaken for sz • Happens more often with coming out of sedation • Must be differentiated from myoclonic status (poor prognosis)
Pathophysiology – Pulmonary Injury • Aspiration as little as 1-3 cc/kg can cause significant effect on gas exchange • Increased permeability • Exudation of proteinaceous material in alveoli • Pulmonary edema • decreased compliance
Pathophysiology – fresh vs. salt • Both forms wash out surfactant • Damaged alveolar basement membrane pulmonary edema, ARDS • Theoretical changes not supported clinically • Salt water: hypertonic pulmonary edema • Fresh water: plasma hypervolemia, hyponatremia • Unless in Dead Sea • Humans (most aspirate 3-4cc/kg) • Aspirate > 20cc/ kg before significant electrolyte changes • Aspirate > 11cc/kg before fluid changes
Pathophysiology • Findings at autopsy • Wet, heavy lungs • Varying amounts of hemorrhage and edema • Disruption of alveolar walls • ~70% of victims had aspirated vomitus, sand, mud, and aquatic vegetation • Cerebral edema and diffuse neuronal injury • Acute tubular necrosis
Pathophysiology – Pulmonary edema • Findings at autopsy • Wet, heavy lungs • Varying amounts of hemorrhage and edema • Disruption of alveolar walls • ~70% of victims had aspirated vomitus, sand, mud, and aquatic vegetation • Cerebral edema and diffuse neuronal injury • Acute tubular necrosis
Signs & Symptoms • 70% develops sxs within 7 hrs • Alertness agitation coma • Cyanosis, coughing & pink frothy sputum (pulm edema) • Tachypnea, tachycardia • Low grade fever • Rales, rhonchi & less often wheezes • Signs of associated trauma to the head & neck should be sought
Prognosis • Better outcomes associated with early CPR (bystander) • C-spine protection: • Transport • Continue effective CPR • Establish airway • Remove wet clothes • Hospital evaluation
Labs & Tests • Min electrolyte changes • Increase WBC • Hct & HgB normal initially • Fresh water: Hct falls due to hemolysis • Inc. in free HgB w/o a change in Hct • DIC occasionally • ABG – metabolic acidosis & hypoxemia • EKG • Sinus tach, non spec ST-segment & T-wave changes • Resolved within hrs • Ominous- vent arrhythmias, complete heart block • CXR • May be nl initially • Patchy infiltrate • Pulm edema
Treatment • ED eval • Admit if: CNS or respiratory symptoms • Observe for 4-6 hours if • Submersion >1min • Cyanosis on extraction • CPR required
Treatment: ED discharge • ED eval • Admit if: CNS or respiratory symptoms • Observe for 4-6 hours if • Submersion >1min • Cyanosis on extraction • CPR required
Predicting Ability for ED Discharge • Several studies support selected ED discharge • Child can safely be discharged home if at 6 hours after ED presentation: • GCS > 13 • Normal physical exam/respiratory effort • Room air pulse oximetry oxygen saturation > 95% -Causey et al., Am J Emerg Med, 2000
ICU treatment: Respiratory • PPV • Treatment of bronchospasm • Steroids: no benefits • Bronchoscopy • Prophylactic abx: no benefits • Surfactant: no beneficial -
ICU treatment: Cardiovascular • Re-warming • CBF decrease 6-7% / ºC drop • LOC 34ºC • Pupil dilate at 30ºC • V-fib 28ºC • EEG isoelectris 20ºC -
ICU treatment: CNS • ICP monitoring - not indicated, typically irreversible hypoxic cellular injury • Brain CT – not indicated, unless TBI suspected • Mild hyperventilation? • Osmotherapy – not indicated • Corticosteroids (dexamethasone) - no proven benefit • Seizures - treat aggressively • Shivering or random, purposeless movements can increase ICP • Hypothermia and barbiturate coma - highly controversial & unlikely to benefit the patient (31 comatose kids, J Modell, NEJM 1993) -
ICU treatment: Others • Antibiotics: no benefit or prophylaxis, may increase superinfection • Fulminant strep pneumo sepsis has been described after severe submersion • Steroids – no demonstrated benefit -
Prognosis predictors • Poor outcomes • Age < 3yrs • Submersion time: >10 min • Time to BLS >10 min • Serum pH: <7.0 • CPR >25 min • Initial core temp <33ºC • GCS <5 -
Prognosis predictors • Prolonged resuscitation may increase the success of resuscitation w/o normal neurologic recovery After 25 min of full but unsuccessful resuscitation, thin “PROGNOSIS” -
Effects of near drowning • Divorce • Sibling psychosocial maladjustment • 100,000 yrs of productive life lost • $4.4 million/yr in direct health care costs • $350-450 million/yr in direct costs • $100,000/yr to care for the neurologically impaired survivor of a near drowing -