Near Drowning Flashcards
New Drowning Outcome According to WHO
Death
With Morbidity
With no morbidity
Near Drowning Definition
When a victim survives a liquid submersion, at least temporarily
Dry Drowning Definition
As soon as fluid is inhaled the bronchi constricts in response to a parasympathetic mediated reflex
Due to involuntary laryngospasm liquid does not enter the lungs
10-20% of victims maintain the laryngospasm until cardiac arrest
Have lidocaine ready for the laryngospasm
Lungs of near-dry drowning victims are normal
Wet Drowning Definition
As oxygen levels fall the glottis relaxes and the liquid enters the lungs
When there is fluid in the lungs it will interfere with surfactant ability and look similar to ARDS
Aquatic Distress
The “classic” picture of drowning
Often, but not always, precedes drowning
Visible, active/violent/abrupt movements
This will only last 20-60 seconds
Instictive Drowning Response
- The more typical picture of drowning
- Behaviorsinstinctively taken by someone drowning (or close to drowning)
- Noiseless and subtle behaviorsthat are instinctive
- Will remain in the same position and extend arms out to the sides
- Mouth is sinking below and reappearing above the water
- Most drowning victims cannot yell for help because they are having trouble breathing
- Young children will struggle less than adults and can look like they are doing the dog paddle in the water
Sequence of Drowning
Panic and violent struggle to return to the surface
Period of calmness and apnea
Swallowing of large amounts of fluid, followed by vomiting
Gasping inspirations and aspirations
Convulsion
Coma
Death
SALT WATER VS FRESH WATER
- Pathologic changes in the lungs essentially the same
- Reduction in pulmonary surfactant, alveolar injury, atelectasis, and pulmonary edema
- Salt water near-drowning victims often have more electrolyte disturbances
- Also if you swallow enough fresh water you will have electrolyte imbalance
Cold Vs. Warm Water
> 20 °C is warm; < 20°C cold
Cold water immersion will stimulate the diving reflex in young children (apnea, bradycardia, core-saving vasoconstriction)
Because water is an excellent conductor of body heat (cold water can cool the body 25 times faster than air in the same temperature), because evaporation further reduces an individual’s body heat and produces hypothermia
Clean Vs. Unclean Water
E.g. swamp, pond, sewage, mud, chlorine pool
May have aspirated pathogens and solid material
Risk of developing pneumonia and ARDS is much higher
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Age
The younger the better outcome
Younger people tend to crash hard but easier to bring back
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Submersion Time
The shorter, the better
60 min is the upper limit in cold water submersion
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Water Temperature
The colder the better
Range 27-70oF
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Water Quality
The cleaner the better
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Other Injuries
None Serious
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Amount of Struggle
Less struggle the better
FAVORABLE PROGNOSTIC FACTORS IN COLD WATER NEAR-DROWNING
Suicidal Intent
Lower survival rate among victims who attempted suicide than victims of accidental submersion
Pathophysiology
This is in regards to wet near-drownings, as dry near drownings will have normal lungs
- Laryngospasm
- Noncardiogenic pulmonary edema
- Decreased surfactant
- Alveolar shrinkage and atelectasis
- Due to the pulmonary edema
- Alveolar consolidation
- Bronchospasm
- Pulmonary hypertension
- Secondary hypoxemia or inflammatory mediator release
most important contributory factors to morbidity and mortality from drowning
The most important contributory factors to morbidity and mortality from drowning are hypoxemia and acidosis and the multiorgan effects of these processes.
Central Nervous System Damage
- May be caused by
- A primary injury (prolonged hypoxemia during episode)
- Secondary causes (reperfusion injury, cerebral edema, seizures, arrhythmias)
- May be a concomitant head or spinal cord injury
- CNS injury remains the major determinant of subsequent survival and long-term morbidity in cases of drowning. Two minutes after immersion, a child will lose consciousness. Irreversible brain damage usually occurs after 4-6 minutes.
The Heart and Near Drowning
Can result in myocardial dysfunction
Blood Volume Changes and Near Drowning
If more than 11 mL/kg of water is aspirated
Hypovolemia can result due to the fluid losses from increased capillary permeability
Electroylte Changes and Near Drowning
If more than 22 mL/kg of water is aspirated
CLINICAL MANIFESTATIONS
Apnea or tachypnea
Increased HR and BP
Cyanosis
Cough with frothy, white or pink sputum
Crackles on auscultation
Restrictive lung pathophysiology
ABG
Resp acidosis with hypoxemia
Metabolic acidosis if lactic acid present
Lactic Acid may be present if there is a lot of struggling and they used a lot of energy
CXR
Initial CXR may be normal; may deteriorate within the first 48-72 h
Pulmonary edema and atelectasis
Fluffy infiltrates; air bronchograms
Oxygenation Indices
Qs/Qt
Increased
Because the alveoli are filled with fluid
Oxygenation Indices
DO2
Decreased
Oxygenation Indices
VO2
Normal
Oxygenation Indices
C(a-v)O2
Normal
Oxygenation Indices
O2ER
Increased
Oxygenation Indices
SvO2
Decreased
PRE-HOSPITAL MANAGEMENT
Conserve heat/maintain body temperature
Remove wet clothes, cover
All drowning victims should get 100% O2
If in cardiac arrest: CPR; establish an airway
HOSPITAL MANAGEMENT For the Spontaneously Breathing Patient
Intubation and ventilation if PaO2 < 60 mmHg on FiO2 of 0.50 or higher, or if respiratory acidosis present (<7.25)
NIPPV can be considered prior to intubation if patient is awake and alert
Hospital Management
Mechanical Ventilaition
ARDS/lung protective strategy with permissive hypercapnia as necessary
Hospital Management
Bronchodilators (If bronchospasm is present)
Manage Electroyle imbalance
Surfactant Therapy
Permissive Hypothermia
Hospital Management
Warming of the Patient
Nearly all drowning victims are hypothermic to some degree
Warm IV solutions, heated lavage, Active humidity on the ventilator
Heating blankets (Bear hugger)
(Rare) Cardiopulmonary bypass and blood warming
**Rewarming may be balanced by a goal of permissive hypothermia for neuroprotection…more research needed (Especially in victims that required CPR)
Resuscitation should not end even if patient does not respond until a close approximation of normal body temperature is reached
Hospital Management
Treatment for Fluid Depletion
Fluids, possibly inotropes
Hospital Management
Bronchoscopy
To remove foreign material if present (debris, vomit)
Noncardiogenic Pulmonary Edema
Due to increased permeability of the membrane fluid from the pulmonary capillaries will move into the perivascular spaces, peribronchial space, alveoli, bronchioles, and bronchi (Interstitial edema)
As a consequence of fluid movement, the alveolar wall and interstitial space swell, pulmonary surfactant concentration will decrease, and surface tension will increase
Excessive fluid in the interstitial space causes lympathetic vessels to dilate and lymph flow to increase
Tachypnea in Near Drowning
Stimulation of peripheral chemoreceptors (hypoxemia)
Decreased lung compliance- Increased ventilatory rate relationship
Stimulation of J receptors
Anxiety (conscious patient)
Cough with frothy, white or pink sputum in Near Drowning
the fluid that accumulates in the tracheobronchial tree is churned into a frothy white (sometimes blood tinged) sputum as a result of air moving into and out of the lungs (generally by means of mechanical ventilation)
What Happends to Virutally Every Near Drowning Patient
Virtually every near drowning victim suffers from hypoxemia, hypercapnia, and acidosis (acute ventilatory failure)
Hypoxemia will generally persists after aspiration of fluids in the airway (wet drowning) because alveolar capillary damage and continued intrapulmonary shunting
The degree of hypoxemia is directly related to the amount of alveolar capillary damage
