Differences in volume, density, electrolyte concentration, and total proteins in the fluid of the paranasal sinuses of freshwater and saltwater drowning victims: a systematic review and meta-analysis.

This study summarized the available evidence on the differences in volume, density, electrolyte concentration, and total proteins in paranasal sinus fluid between freshwater and saltwater drowning victims. A systematic search was conducted in electronic databases and gray literature, resulting in the inclusion of five studies with 234 drowning victims (92 saltwater incidents and 142 freshwater incidents). Meta-analyses using the inverse-of-variance method and a random-effects model were performed, reporting effect sizes as standardized mean differences (SMD) with 95% confidence intervals (CI). The findings showed a significantly higher sinus density in saltwater drowning cases compared to freshwater drowning cases (SMD 0.91, 95% CI 0.50 to 1.32). However, no significant differences were observed in sinus fluid volume. Saltwater drowning victims exhibited higher electrolyte concentrations (sodium: SMD 3.77, 95% CI 3.07 to 4.48; potassium: SMD 0.78, 95% CI 0.07 to 1.49; chloride: SMD 3.48, 95% CI 2.65 to 4.31; magnesium: SMD 4.01, 95% CI 3.00 to 5.03) and lower total protein concentrations (SMD - 1.20, 95% CI - 1.82 to - 0.58) in sinus fluid compared to freshwater drowning victims. This meta-analysis highlights the importance of analyzing the characteristics and composition of sinus fluid in forensic investigations of drowning cases. While no differences were found in sinus fluid volume, saltwater drowning victims exhibited higher sinus density, elevated electrolyte concentrations, and lower total protein concentrations compared to freshwater drowning victims.