Drowning

1. Drowning NEJM Review NEJM 2012;366:2102-10

2. 0.7% all deaths worldwide • >500,000 deaths/year • Leading cause death boys 5-14yrs • Second leading cause of death due to injuries 1-4yrs • 25% are > 14y/o • Males > Females (4:1) • Alcohol involved • Epilepsy

3. How many people drowned in NZ in 2010? • 87 people died of drowning in New Zealand during 2010. This is the lowest annual toll since 1980. Three regions (Waikato, Tasman and West Coast) had increased drowning tolls from 2009. • 160 people were hospitalised due to immersion incidents in New Zealand during 2010. This is the highest annual toll since 2003. The five year average is 136 hospitalisations per year. Deaths Auckland – 18 NZ - 87 Hospitalisations 49 160

4. Deaths *Watersafety NZ

5. Site of accidentHospitalised cases – does it really matter to us?*Watersafety NZ

6. Definitions • “Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid”WHO 2002 • Respiratory impairment as airway goes below the surface (submersion) or water splashes over the face (immersion) • Rescue at any time, process of drowning interrupted  nonfatal drowning • Death as a result of drowning fatal drowning • Water rescue: Any submersion or immersion incident w/o evidence of resp impairment

7. Terms to avoid • Near drowning • Dry or wet drowning • Secondary drowning • Active and passive drowning • Delayed onset of respiratory distress

8. From Auerbach: Wilderness Medicine, 5th ed. ( Submersion or near-drowning) Fig 68.4.

9. Cold Water Drowning • Immersion syndrome (water temp >5o less than body temp) • Death shortly after cold water immersion 2o vagally induced VF arrest (?diving reflex) • Cold Water shock • On exposure to cold water, uncontrollable gasping for approx 1 min that will result in aspiration if head submerged • Catecholamine surge that may precipitate arrythmia • Cooling peripheries decrease nerve conduction and impair muscle co-ordination and impair self rescue • Immersion hypothermia

10. RESPIRATORY EFFECTS

11. Which of the following factors is most relevant in history? Fresh Water/Salt Water/Polluted water How many mls/kg does the average submersion injury aspirate ? How many mls/kg aspirate of salt water causes alteration of blood volume? electrolytes? Orlowski et al instilled differing NaCl conc into dog ETT tubes

12. Pulmonary Injury Effects of alveolar fluid Effects of alveolar membrane damage Effects of vascular endothelial damage Inflammatory response

13. Nasty Water • Pollutants • Hydrocarbons (Low viscosity /High Volatility) • Heavy Metals • Particulates • Microorganisms • Gram Negative • Pseudomonas, Aeromonas, Burkholderia, Legionella • Gram Positive • Streptococci and Staphylococci (from mouth) • Fungi • Pseudoallallescheriaboydii • Prophylactic treatment not indicated (maybe if raw sewage)

14. Pulmonary • Aspiration (1-3mL/kg) can reduce gas exchange • Bronchospasm  • Chemical pneumonitis • Pulmonary vasoconstriction/hypertension (vagally mediated) • Surfactant destruction •  alveolar instability, atelectasis, and decreased compliance, with marked ventilation/perfusion (V/Q) mismatching • Acute respiratory distress syndrome (ARDS)  • Pneumonia  • Aeromonas, Burkholderia, and Pseudallescheria • Fibrosis, restrictive lung disease, and decreased diffusion capacity

15. Cardiovascular Effects • Hypotension • Shock, acidosis, hypovolemia (natriuresis), autonomic instability • Arrhythmias • Asystole (55%), • Ventricular tachycardia/fibrillation (29%) • Bradycardia (16%) • Brugada • Long-QT syndromes

16. Other systems • Neurological • Neurologic asphyxia • Seizure, coma, death • Encephalopathy • Cardiocerebral protection? • (Remember head trauma/ • c-spine) • Renal • Natriuresis • Acute renal failure • Rhabdomyolysis • Electrolytes/Hem • Normal aspiration of 3-4ml/kg • Changes in blood volume at 11ml/kg • Haemolysis at 22ml/kg (1.5L)

18. Rescue and in-water resuscitation Areas with lifeguards: • <6% require medical attention • 0.5% require CPR • Untrained resuers need to avoid drowning themselves • Conscious: Take to land and initiate BLS • Unconscious: Ventilation alone. • C-spine injuries <0.5%

19. Initial Resuscitation on land • Rescue ventilation essential • Cardiac arrest due primarily to lack of oxygenation so CPR should follow ABC approach • 5 initial rescue breaths • 30:2 • Most frequent complication is regurgitation of stomach contents. 65% rescue breathing alone and 85% who require CPR • Avoid abdominal thrusts or placement head down

20. ADVANCED PREHOSPITAL CARE

23. Obvious death • Submerged for >1 hour • Normothermia (>30°C) with asystole with CPR >30min • Rigor mortis • Dependent lividity • No apparent CNS function

24. CARE IN THE ED

25. Scoring Systems on Hospital Arrival The simple approach Modell & Conn 1984 – in ED within 1 hr of rescue (paeds) • Asymptomatic • Symptomatic • Critical • Obviously dead

26. Asymptomatic patient No comorbidities If at 4 - 6 hours: CXR, ABG normal Normal vitals on air Remain ASx = discharge with advice If aspirated potential for delayed deterioration

27. Symptomatic Patient • Consider foreign material in airway (approx. 50% of surf submersions) • Salbutamol / Ipratoprium nebs for bronchospasm • NG placement on free drainage may improve ventilatory distress • High risk for vomiting and gastric content aspiration • Suction +++ • Most will require fluid resuscitation secondary to diuresis • Beware hypothermia and trauma

28. Hypothermia • Common following drowning • Arrhythmias more common, can be refractory at temps < 30°C – limit defibrillation shocks to 3 • Dose interval of resuscitation drugs is doubles at temps between 30 and 35°C • Continue resuscitation until core temp at least 32°C • Generally allow temp to rise by 0.25-0.5°C /hr to reduce haemodynamic instability • Vasodilation during rewarming  BP, large volumes of warmed IVF • Therapeutic hypothermia

29. Treatment in the ICU Indications for Intubation: • Decreased GCS for airway protection • Unable to maintain PaO2 > 90 on high flow, non-rebreather mask • Unable to maintain PaCO2 < 45

30. Respiratory: • Tend to recover much faster than pts with ARDS • Late pulmonary sequelae uncommon • Wean ventilation after 24hrs

31. Ventilation • Most text books will support a trial of NIV if blood pressure and GCS appropriate, however there are no literature to support its use • Start low and titrate up • volume support • Vt low – 6mls/kg • PEEP 5-10 cm H20 only if PaO2 < 60 on FiO2 <0.6 • Ventilate for 24 hours to allow regeneration of surfactant

32. Pneumonia • No prophylactic antibiotics • No prophylactic steroids • If starting Abx, start broad

33. Circulatory: • Oxygenation • Rapid crystalloid infusion • Normalisation of body temp • Early cardiac dysfunction in Grade 4-6 • No evidence for specific fluid therapy, diuretics or water restriction

34. Neurologic: • Aim for normal Glc, paO2, pCO2 • Induced hypothermia – core temp 32-34°C may be neuroprotective • Recent reports on drowning documented good outcomes with the use of therapeutic induction of hypothermia after resuscitation, despite a predicted poor outcome Vanden et al. Part 12: cardiac arrest in special situations: drowning:2010 American Heart AssociationGuidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122:Suppl 3:S847-8 Guenether U et al.Extended theraeutic hypothermia for several days during extra-corporeal membrane-oxygenation after drowning and cardiac arrest: two cases of survival with no neurological sequelae. Resuscitation 2009;80:379-81

35. Unusual Complications • SIRS after resuscitation has been reported • Should not be misinterpreted as infection • Sepsis and DIC in first 72hrs • Renal insufficiency or failure rare

37. Prognostic factors, patients <20 years Quan L, Kinder D. Pediatric submersions: prehospital predictors of outcome [see comments]. Pediatrics 1992;90:909±913. & Cummings P, Quan L. Trends in unintentional drowning: the role of alcohol and medical care. JAMA 1999;281:2198±2202. 100% mortality • Submersion duration > 25 min • Resuscitation duration >25 min • Pulseless cardiac arrest on arrival to ED Other • VT/VF on initial ECG (93%) • Fixed pupils in ED (89%) • Severe acidosis (89%) • Respiratory arrest in ED (87%) • Unresponsive in ED

38. Who Lives or Dies • Good Prognostic Indicators • Short submersion • BLS/ALS on scene • Good response to initial resuscitation • Alert on admission • Older child or adult • Water temp < 5-10°C • Bad Prognostic Indicators • Submersion > 25 minutes • Cardiac arrest requiring > 25 minutes of ALS • Ongoing CPR in ED • Fixed, dilated pupils in ED • pH < 7.1 • Age < 3 y/o • GCS < 5 in ED

39. Other Ineffective Treatments • No head down positioning • No Heimlich maneuver • No diuretics  • No prophylactic antibiotics • No steroids

40. 1-10-1

41. Beware of Diving