Drowning is never dry

The water incident database (WAID) 2012 to 2019: a systematic evaluation of the documenting of UK drownings

Background

Death by drowning is a leading cause of accidental death in the United Kingdom (UK) and worldwide. The World Health Organization (WHO) states that effective documentation of drowning is required to describe drowning frequency and to underpin effective drowning prevention intervention, thus improving the quality of data describing drowning frequency represents a key initiative. The water incident database (WAID) has been used to document UK fatal and non-fatal water-based incidents since 2009. WAID has not undergone a systematic evaluation of its data or data collection procedures to establish if the database meets the WHO requirements. The present study investigated the characteristics of UK fatal drowning incidents and audited current WAID data capture procedures.

Methods

Data for the fatal drowning cases recorded between 2012 and 2019 were reviewed. Descriptive data were generated 1) to describe fatal drownings in the UK’s WAID in this period; 2) a sub-set of drownings were audited i) for completeness of data entry and, based on source documents, ii) for quality of data entry; 3) these processes were used to make recommendations for onward revisions to WAID.

Results

A total of 5051 fatalities were recorded between 2012 and 2019. Drowning was most frequent amongst males aged 35 to 60 years (n = 1346), whilst suspected accidents and suicides accounted for 44 and 35% of fatalities. Suicide by drowning was at a peak in the most recent year of data analysed (i.e., 2019; 279 cases) highlighting an urgent need for targeted intervention. Audit part 2i) indicated that 16% of all fields were incomplete, thus indicating potential redundancy, duplication, or the need for onward review. Audit part 2ii) indicated high levels of agreement (80 ± 12%) between audited cases and the ‘true’ WAID entries.

Conclusions

This study confirms WAID as a rigorous, transparent and effective means of documenting UK drownings thereby meeting WHO requirements for data quality; yet future improvements are recommended. Such findings allow researchers and policy makers to use WAID to further investigate UK drowning with a view to improving public safety measures and drowning prevention interventions. Observations alongside several expert recommendations have informed a revised version of WAID.

Experimental water injection into lungs using an animal model: Verification of the diatom concentration test to diagnose drowning

BACKGROUND

In forensic medicine, the diatom test is used to diagnose drowning. Drowning and postmortem immersion can be distinguished by calculating the ratio of diatom concentration in the lungs and drowning water (L/W ratio). However, this claim was based on the unproven hypothesis that diatoms may be concentrated in the lungs due to respiratory movements. This study was conducted to examine whether the L/W ratio increased with experimental water injection.

METHODS

A total of two experiments was performed using 22 non-drowned cat carcasses found on dry land. First, for the experimental postmortem immersion, we soaked seven whole-body cat carcasses in pond water for an hour. Second, the pond water was experimentally injected one or ten times into each harvested lung from seven and eight cats, respectively. In the diatom test, two diatom species (Aulacoseira ambigua and Discostella asterocostata) that were dominantly observed in pond water as well as other diatom species were counted separately. The L/W ratios of each cat were calculated. Univariate linear regression analysis was performed to demonstrate the association among L/W ratios and the three categories of the experiments. The L/W ratios of the two experiments were compared with those of drowning or postmortem immersion cases of humans or cats.

RESULTS

It was revealed that the clear L/W ratio differences between the three groups (experimental postmortem immersion<0.02, 1-injection < 0.2, 10-injection > 0.9 for all diatom counting) were with statistically significant as proven by the univariate regression analyses. In actual cases of cats and humans, L/W ratios were>0.4 for drowning and<0.04 for postmortem immersion.

CONCLUSION

The L/W ratio increased with multiple experimental water injections into the lungs, thereby verifying the validity of the diatom concentration test to diagnose drowning. The diatom test can be used to distinguish between drowning and postmortem immersion in humans and cats by calculating the L/W ratio.