Near Drowning

Naeem Ali, MD

Fellow, Division of Pulmonary and Critical Care Medicine

Myth #1 there are always three surfacings before a serious drowning event occurs

Myth #2 near drowning victims always aspirate large quantites of water

Myth #3 all near drowning victims should receive the Heimlich maneuver prior to resuscitation attempts

Water related injuries:

Definitions

Drowning: death from asphyxia within 24 hours of a submersion event

Near Drowning: a submersion episode of enough severity to warrant medical attention

-or-

any submersion accident with survival

Secondary drowning: death from complications of a submersion event greater than 24 hours after

the event

Immersion syndrome: sudden death due to cardiac arrest after sudden immersion in cold water

(vagal)

Submersion injury: any of the above events

 

Depth injury: usually scuba related and can include decompression sickness and barotrauma

 

Epidemiology and Prevalence

Impact

In 1990 over 4700 fatal cases of drowning in the US

Majority occur in children 50% occur in the less than 4 year old age group

2nd most common cause of accidental death in children

Heavy loss in terms of years of productivity goes without saying

Hospitalizations

Pediatric ER study showed average of 31,000 visits for near drowning

Admission rate was 25%

Prevalence/Incidence

Heavy weighting towards children and young adults

Annual estimates:

6000-8000 drownings per year in the US

over 140,000 cases worldwide

Near drowning has been estimated anywhere from 2-20 times the rate of drownings

Difficult to estimate because of lack of reporting

Annual estimates:

15,000-70,000 near-drownings per year in the US

 

Early first peak at 2-4 years old ( 8 deaths per 100,000 population per year)

Second peak at 15-25 years old (11 deaths per 100,000 population per year)

 

Male: Female = 3.3:1

Black: White = 2:1

 

Adult near drownings remain relatively constant after age 40

Varies by region (coastal, non-coastal and prevalence of certain occupations)

Highest rates of near drownings occur in the state of Alaska

Circumstances

50% of all drownings occur in pools

98% of all drownings occur in freshwater

 

Adult drowning and near drowning have an increased association with boating and alcohol use.

 

Pathophysiology

Events in Drowning

Based on animal "models"

Struggle with breath-holding

Ceased movement and exhalation

Reflexive inspiration with or without seizure activity

Death

 

Pulmonary Manifestations

Aspiration into lower respiratory tree

Occurs in a majority of victims (80-5%)

10-15% aspirate no water at all (intense laryngospasm)

amount is often small often <10 ml/kg and almost always <22 ml/kg (autopsy studies)

 

Fresh Water

Fluid in the alveolus is quickly absorbed into the systemic circulation

Surfactant dysfunction

Residual dilution of normal surfactant

Hypotonicity leads to alterations of the proteins themselves

Resultant atalectasis and intrapulmonary shunting

 

Salt Water

Hypertonic solution in the alveoli

Resultant pulmonary edema

Experimental instillation of 22 ml/kg of salt water into the airway resulted in the drainage of 33 ml/kg after 5 mins

 

Despite theoretical differences there are no clinical differences in management

 

Extra-pulmonary Manifestations

Most profound alteration is neurologic

CNS injury accounts for >90% of sequelae greater than 30 days out

Mechanism is hypoxia (ischemia-reperfusion), but consider venous gas embolism

Renal

ATN secondary to hypoxia (or hypotension if shock develops)

Cardiovascular

Arrhythmias and hypoxic cardiomyopathy

Hematologic

Hemoconcentration in saltwater

Hemolysis in freshwater

DIC in hypoxia, hypotension or hypothermia

Electrolytes

Usually no significant abnormalities except in,

Industrial accidents

Saltwater events with large volume ingestion (GI absorption)

Dead Sea near drownings have higher case fatality rates

 

 

Special Situations

Hypothermia

Anecdotal reports relate better prognosis after hypothermic near drowning

Many in children, but some in adults

alt Lake City, 2 yo with complete recovery after 66 min submersion in 5 C water

Mild hypothermia (32-35C) induces sympathetic response and increased O2 demand

Moderate hypothermia (<32C) decreases O2 use and cerebral perfusion

Increases risk of asystole or fibrillation

1. more rapid cooling in children (increased BSA: weight ratio)

2. rapid cooling may induce paralysis and inhibit reflexive aspiration

Rewarming

<29.5C active, rapid

29.5-32C active

>32C usually hemodynamically stable

 

Near Drowning at Depth

Shallow water blackout hypoxic encephalopathy related to pre-dive hyperventilation

(snorkelers)

Mostly recreational scuba divers

Usually problems with the ascent

Pressure changes are rapid (33feet= 1 ATM)

Either event at depth requiring emergency ascent or panic during routine ascent

Higher fatality rate, see below

 

Rapid ascent injury

Decompression sickness

Caused by rapid accumulation of inert gases from depressurization

Starts in soft tissues and moves into venous circulation

DCS I (mild) "the bends"

DCS II (serious)

Venous Gas Embolization (VGE)

Can lead symptoms if:

1. arterialized from a PFO or pulmonary shunt

2. obstructive shock

3. inflammatory mediator stimulation (non-cardiogenic edema, bronchospasm)

Arterial Gas Embolization (AGE)

Always symptomatic

Usually secondary to pulmonary barotrauma and entrance through pulmonary veins

Barotrauma

Second most common cause of death from Scuba diving after aspiration

Ascent with closed glottis leads to rapidly expanding gas in the lungs

Can lead to pneumothorax and pneumomediastinum (and AGE)

 

Co-morbid Illness

As age increases the association co-morbid illness rises

Seizure disorder is a lifetime association

Absent seizures polysubstance abuse is highest

Rarely cardiac disease and or syncopal illness

Association with several congenital long QTc syndromes

 

Management

Resuscitation

In Water:

1. awareness of need for c-spine precautions

2. rescue breathing ASAP

Do not attempt compressions

On Land:

1. activate EMS

2. basic CPR (ABC's)

Do not attempt the Heimlich maneuver unless "high suspicion for foreign body" obstruction of the airway

 

Stabilization

Most near drowning victims do not require prolonged observation if stable over two hours and normal CXR

Subset who need mandatory 24 hr observation

1. >1min submersion time

2. Cyanosis on resuscitation

3. Required rescue breathing or mouth to mouth

Late sequelae occur

Pulmonary and cerebral edema can occur upto 24 hrs later

 

Otherwise initial management the same as other causes of respiratory failure

Non-invasive ventilation has been used successfully

PEEP as in other causes of non-cardiogenic pulmonary edema

 

Neurologic injury is very common

Special attention to signs of increased ICP

In general would like to maintain normal pCO2, SBP, volume status, glucose and recognize all seizure activity early

 

HYPER therapy

Disproven in randomized pediatric studies

Therapy consisted of:

1. diuretics

2. hyperventilation

3. hypothermia

4. barbituates

5. paralytics

6. +/- steroids

7. ICP monitors

 

SUPPORTIVE therapy is most efficacious

Neurologic recovery clearly is worse if:

Glucose containing solutions are given

PCO2 is elevated

ICP raised after 72 hours

Special Situations

Drowning at Depth

In situations of DCS I and DCS II as well as AGE and VGE

Hyperbaric oxygen therapy is required

Prior to this Oxygen therapy should be applied

 

Pneumonia Associated with Near Drowning

Retrospective reviews show no benefit to "prophyllactic antibiotics"

Incidence of pneumonia ranges from 25-60% of near drownings

Seems more likely to occur in male teens (EtOH?)

Otherwise healthy, but has a 60% case fatality rate

Odd organisms more common

Aeromonas, Burkholderia, Pseudoallescheria

Risk increases with:

1. warm water

2. stagnant water

3. fresh water

4. length of hospitalization (nosocomial)

5. induced hypothermia

Diagnosis

Recommend extreme vigilance and at outset of fever or new infiltrates initiatecultures and possible bronchoalveolar lavage.

Obtain environmental cultures

 

Bronchoscopy is only definitely proven to be of help in near drowning with obvious volume loss on CXR for removal of aspirated particulate matter

 

Outcomes and Prognostic Categories

Mortality/Resuscitation Rates

Overall 25% mortality

Initial resuscitation rates higher, but variable

Resuscitation rates are better when:

1. revival at the scene

2. child victim (>3yo)

3. cold water submersion

4. shorter submersion times

 

Morbidity and Risk Stratification

6% of all near drowning victims have neurologic sequelae (10% of all survivors)

 

No ED admission clinical variables have provided good clinical prognostic data

GCS alone at admission of 3 (lowest) 15-29% survival (2-12% without neuro deficit)

 

Retrospective review of consecutive near drowning pts showed that the need for CPR in the ED had a 100% rate of poor outcome (mortality+permanent encephalopathy)

 

Proposed schemes

GCS of less than 5 + unresponsive pupils + no clinical improvement in 12 hours = POOR

Outcome

Orlowski score

1. Age 3 or older

2. Submersion time >5 min

3. No resuscitative efforts for greater than 10 mins after rescue

4. Comatose on admit to the ER

5. Arterial pH <7.10

Two or less variables has a greater than 90% good outcome rate

Three or more associated with less than 5% chance of normal recovery

 

Prevention

Adequate pool enclosures could reduce drowning and near drowning morbidity and mortality by 45%

 

 

References:

 

Sachdeva, RC, "Near Drowning" Critical Care Clinics, 15 (2), April 1999, 281-96.

Ender, PT, et al, "Pneumonia Associated with Near Drowning", CID, 25, 1997, 896-907.

Brown, SD, et al, "Diving Medicine and Near Drowning," Critical Care by Hall, Schmidt and Wood.

Varon, J, "Cardiopulmonary Resuscitation: Lessons from the past," The Journal of Emergency Medicine, 9, 1991, 503-7.

Ellis, RJ, "Severe hypernatremia from seawater ingestion…" WJM, 167 (6), 1997.

Harris, JB, "Scuba diving accident with near drowning and decompression sickness," AJR, 164, 1995, 592.

Joseph, MM, "Epidemiology of hospitalization for near drowning", Southern Medical Journal, 91 (3), March 1998, 253-5.

Ackerman, MJ, "Swimming, a gene-specific arrhythmogenic trigger for the long QT syndrome, " Mayo Clinic Proceedings,

74, 1999, 1088-94.

"Near drowning and Drowning", in Critical Care, by Civetta, Kirby and Taylor.

Weinstein, MD, "Near-drowning: Epidemiology, pathophysiology and treatment", The Journal of Emergency Medicine, 14

(4), 1996, 461-7.

 

Updated 3/17/00

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