Near-drowning and clinical laboratory changes.

Area of Science:

• Forensic Medicine
• Pathophysiology
• Toxicology

Background:

• Clinical laboratory findings in human drowning contrast with animal experimental models.
• Animal drowning studies often show erythrocytic lysis and hyperkalemia, unlike observed human cases.
• Recent discussions necessitate a re-evaluation of the drowning pathophysiological process in humans.

Purpose of the Study:

• To analyze clinical laboratory data from near-drowning cases in humans.
• To investigate the pathophysiological differences between human and animal drowning models.
• To determine the primary cause of death in human drowning incidents.

Main Methods:

• Retrospective analysis of clinical laboratory data from 31 near-drowning cases.
• Inclusion of data on pH, potassium, sodium, chloride, hemoglobin, and total protein.
• Categorization of cases into fresh water (23) and brackish water (8) near-drowning incidents.

Main Results:

• Nearly all cases (96%) showed reduced pH due to hypoxic acidosis.
• Hyperkalemia was rare (6.5%), and hemoglobin levels were mostly normal (83%).
• Intravascular red cell lysis and significant electrolyte disturbances were not observed in human cases.

Conclusions:

• Human drowning is primarily characterized by hypoxic cerebral injury, not red blood cell lysis or electrolyte imbalance.
• Animal drowning models are not directly comparable to human near-drowning due to differences in aspirated fluid volume and resulting pathophysiology.
• The findings underscore the critical role of cerebral hypoxia in human drowning fatalities.