Pathophysiological features
The key issue during immersion in water is acute hypoxia. Under normal conditions, the onset of clinical death is critically accelerated, taking only up to 3 minutes. This is due to the enormous expenditure of internal oxygen reserves: the victim expends all available energy on intense muscular effort while trying to stay afloat.
However, the situation changes fundamentally when drowning occurs in cold water. Rapid cooling of the body triggers the hypothermia effect. The drop in body temperature leads to a total slowdown of all metabolic processes. Oxygen consumption by brain tissues drops to a minimum. Thanks to this protective mechanism, the timeframe for clinical death is significantly extended. Medicine has documented reliable cases where full resuscitation of a person was possible even after being underwater for more than 20 minutes.
Differences between fresh and salt water
First aid tactics strictly depend on the chemical composition of the body of water, as the pathogenesis of lung injury is determined by the difference in fluid osmolarity.
- Freshwater. The osmolarity of river or lake water is significantly lower than that of blood. As soon as the fluid enters the alveoli, physical laws dictate that it is instantly absorbed across the membrane directly into the bloodstream. Therefore, rescuers are strictly prohibited from wasting precious time trying to "shake out" or remove water from the trachea and bronchi.
- Saltwater (seawater). The salt concentration in the sea is about 3.5–4%, which makes its osmolarity higher than that of blood. The reverse effect occurs: the liquid part of the blood (plasma) rushes actively from the bloodstream into the lumen of the respiratory tract. Mixing with air and seawater, the plasma forms an abundant frothy liquid. This foam creates an insurmountable mechanical barrier to mechanical ventilation. In such cases, it is necessary to partially remove the fluid. To do this, the victim is lifted very quickly by the lower torso (so the water hangs downward) and the water is allowed to drain. This manipulation must be performed as rapidly as possible.
First aid algorithm
Resuscitation measures are divided into two stages: actions in the water and on the shore.
1. Assistance in the water (during towing):
- Artificial pulmonary ventilation (artificial respiration) must be initiated at the very first opportunity—as soon as the victim's face is above the surface.
- If cardiac arrest is detected, chest compressions must be started immediately without stopping artificial ventilation.
- Important rule: at this stage, no time should be wasted on removing water from the lower respiratory tract.
2. Measures on the shore:
- Removal of water from the stomach. The victim's stomach is always overfilled with swallowed fluid. It is necessary to turn the person onto their side and press firmly on the epigastric region.
- Oropharyngeal suction. Be sure to use a finger or cloth to clear the mouth of mucus, sand, and silt.
- Cardiopulmonary resuscitation (CPR). If a heartbeat is preserved but breathing is absent, perform rescue breaths via the mouth-to-mouth method. In the event of clinical death, full CPR is performed by one or two rescuers.
Further tactics: Regardless of well-being and the duration of submersion, all victims are subject to mandatory hospitalization in a specialized intensive care unit for intensive treatment and monitoring.
Briefly: answers to topical questions
What changes in blood electrolyte composition and circulating blood volume (CBV) occur during freshwater drowning?
During freshwater drowning, fluid is rapidly absorbed from the alveoli into the bloodstream because its osmolarity is lower than that of blood. This leads to the following pathophysiological changes:
- Hypervolemia — an increase in circulating blood volume (CBV).
- Hemodilution — pronounced blood thinning is observed.
- Erythrocyte hemolysis — destruction of red blood cells.
- Hypo-osmolar syndrome — accompanied by arterial hypertension and increased intracranial pressure due to brain cell swelling.
Intracellular components also appear in the plasma as a result of cytolysis and damage to cells of various tissues.
What systemic pathophysiological shifts occur when seawater enters the alveoli?
When seawater enters the alveoli, the liquid portion of the blood rushes into the respiratory tract. This is because the osmolarity of salt water is higher than that of blood; the salt concentration is 3.5–4%. As a result, a frothy fluid forms, which impedes artificial pulmonary ventilation (APV). To partially remove the fluid, it is necessary to very quickly lift the victim by the lower torso so that the head hangs downward.
What specific complications may develop in a survivor after drowning during the post-resuscitation period?
In the post-resuscitation period after drowning, acute respiratory distress syndrome (non-cardiogenic pulmonary edema) may develop. It is characterized by the fulminant development of respiratory failure, progressing hypoxemia, and hypercapnia. The following complications are possible:
- multiple organ dysfunction syndrome causing transient destabilization within the framework of post-resuscitation disease;
- onset of fatal heart failure;
- disseminated intravascular coagulation (DIC) syndrome;
- infectious complications.
The prognosis is assessed as extremely unfavorable.
F-F-F: For Freshwater — Forget it (do not waste time removing water from the lungs). S-S-S: For Saltwater — Spill it (quickly flip upside down for foam drainage).
Class and exam questions
Why does clinical death occur so quickly during drowning?
Due to active muscular work: a panicked attempt to survive burns almost all of the body's oxygen reserves within 3 minutes.
Do you need to try to pour water out of the victim's lungs at the river?
No, freshwater has low osmolarity and is very rapidly absorbed from the alveoli into the bloodstream. You must not waste time removing it.
Why clear the stomach on the shore?
In a drowning victim, the stomach is always overfilled with swallowed water. Pressing on the epigastric region in the lateral position prevents accidental aspiration of vomit into the lungs during resuscitation.
What else to study on this topic
- Specifics of CPR techniques in the water during towing
- Mechanisms of frothy fluid formation when seawater enters the lungs
- Dangers and consequences of stomach overfilling with water
- Delayed complications after successful resuscitation (reasons for ICU admission)
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