Assessment of Mechanical Damage to Odontocete Respiratory Tract Tissues After Controlled Exposure to Blasting

摘要

The odontocete respiratory tract is adapted to withstand the gradual pressure changes associated with diving, yet nothing is known about how it responds to the sudden pressure changes of a blast exposure. Our goal is to characterize respiratory injuries resulting from postmortem blast pressure exposures. Tissues were harvested from 17 freshly dead odontocetes exposed to blast pressures post mortem (supplied by D. Ketten). Blast pressure exposure levels were not revealed to enable unbiased observations. Results indicate that many specimens show dark reddish discoloration of variable intensities that may be evidence of blast-induced trauma. Discoloration was found in the lungs (striped pattern correlating with ribs), larynx (above and below palatopharyngeal sphincter), trachea (uniform throughout lumen), and nasal region (visualized only in unpigmented areas). Kistology revealed abnormal accumulation of gas bubbles in tissue and distended blood vessels. Gas containing tissues may exhibit damage due to dramatic compression/expansion to accommodate changing gas volumes. Abrupt edges to discoloration patches indicate protection, possibly conferred by contact with adjacent tissues. Discoloration patterns are consistent in location but have variable intensity, perhaps reflecting different degrees of exposure. This information may be useful in setting critical exposure limits to prevent harm to odontocetes in the vicinity of a blast event.