Drowning

NEAR DROWNING

Jeffrey W.Parker EMT-P Jeremy Beck EMT-P &

INTRODUCTION 

Drowning is an unexpected tragedy where previously healthy persons are exposed to severe hypoxia leading to death, or in the case of near-drowning, at potential for permanent brain injury and/or neurologic dysfunction.

EPIDEMIOLOGY Males>Females  Although exact number is uncertain, many more individuals survive serious near-drowning episodes  Peak Ages  1-2 years old  15-19 years old 

EPIDEMIOLOGY Freshwater drowning is more common than saltwater drowning, even in coastal areas  Places:lakes/rivers/canals/pools  Toddlers:  Any container of water can be responsible: Buckets/fish tanks/washing machine/toilets/bathtub 

EPIDEMIOLOGY Toddlers drown primarily in swimming pools and account for 75%-90% of all drownings.  Child deaths are not generally from gross neglect, but from momentary lapses in adult supervision  Risk climbs again in the elderly from bathtub drowning 

Associated Risk Factors Intoxication with drugs/alcohol  Venomous stings from aquatic animals  Head/spinal injuries (Diving accidents)  Hyperventilation syndrome (Breath Holding) which suppresses the physiologic response to increased CO2  Pre-existing medical conditions: Seizures/DM/ Syncopal episodes 

Associated Risk Factors MI/pre-existing cardiac disease  Hypothermia  Physical exhaustion  Suicide  Non-accidental trauma (NAT) 

EVENTS For many years , drowning was considered a “Fight for Survival”  Typical scenario of a person screaming for help, arms flailing, struggling to remain on the surface of the water.  This scene is rarely reported by persons at the scene of of drownings 

Common Scenarios Last seen in the home or yard around the pool  Playing alone: Parents occupied by chores (answering the telephone most common)  Typically - no splash heard, if barriers where in place they where circumvented  In the northern states - bucket drowning commonly occurs 

Common Scenarios 

Witnesses report individual was:  Floating on the surface and suddenly becomes motionless  Swimming underwater and stopped  Dove into water and never surfaced  Horsing around underwater and then appeared to play “Possum”  Just quietly disappeared in the water

DEFINITIONS 



Drowning = Death within 24 hours after submersion and suffocation in a liquid medium. Cause is asphyxia from airway obstruction, laryngospasm, or aspiration of liquids Near drowning = Submersion episode with temporary suffocation and loss of consciousness that results in survival (full or partial recovery), or temporary survival that ultimately leads to death after a period of at least 24 hours.

DEFINITIONS 

Secondary drowning= Implies that the patient is initially resuscitated, but death occurs minutes to days (generally 24 hours) after the initial resuscitation. Also known as Delayed death to near-drowning or Post immersion syndrome. syndrome Death frequently due to the delayed onset of respiratory insufficiency.

DEFINITIONS 

Immersion syndrome= Drowning that may be caused by a vagally induced arrhythmia secondary to exposure to cold water (68 F) Enhanced predisposition with the use of alcohol/drugs

DEFINITIONS Wet Drowning= Where a certain amount of water has been aspirated into the lungs. (Amount variable)  Dry Drowning= Laryngospasm which occurs after all spontaneous respiratory efforts cease 

MISUNDERSTOOD FACTS Despite “Hype” regarding the differences between salt and fresh water, it is not generally apparent clinically  Severe E’lyte changes are seen in rare setting after ingestion of large amounts of water  Not generally enough fluid aspiration to change the total blood volume or E’lyte concentration (Seen only with aspiration of > 22ml/kg 

MISUNDERSTOOD FACTS On autopsy, lungs of patients who died in water had various quantities of water in their lungs.  Supports premise that Active respiration and not Passive flow of water determines the volume of water aspirated  Hematologic and renal function usually normal and not impaired  Steroids do not alter course 

MISUNDERSTOOD FACTS  The problem is HYPOXEMIA

from pulmonary injury whether from fresh or salt water.

MISUNDERSTOOD FACTS  All

definitions are esoteric, and all patients should be resuscitated unless there is gross injury, or documented submersion times greater than 1 hour!

PATHOPHYSIOLOGY

Pathophysiology Wet drowning - Water aspiration after aborted laryngospasm 85%  Dry drowning - Anoxia due to laryngospasm 15%  Whatever the mechanism, the final common pathway is profound hypoxemia. 

Fresh Water Vs. Salt Water No difference in electrolytes and hematocrit  Average drowning victim aspirates 3-4 ml/kg  No electrolyte or blood volume changes seen until 22 ml/kg and 11ml/kg respectively 

Fresh Water Aspiration Fresh water produces an increase in airway resistance due to reflex mechanisms  Pathway:  Alveoli surfactant is washed out causing atelectasis  V/Q Mismatch  Alveolar membrane breakdown  Onset of pulmonary edema 

Fresh Water Aspiration Acute respiratory failure  This process can be abrupt or can occur over several hours. 

Salt Water Aspiration Salt water has three (3) to four (4) times the tonicity of plasma  Fills alveoli with fluid  Osmolar gradient gives alveoli ability to draw in fluid  Pulls protein-rich fluid into the alveoli 

Salt Water Aspiration Blood volume decreases  Leads to hypovolemic shock  Causes intrapulmonary shunt leading to hypoxia  E’lytes concentrate (Extracellular)  With large volumes of aspirated fluids  Both types of fluid combine within the alveoli:  Results in Acute Pulmonary Edema 

QUESTIONS?