Abstract
To the Editor:
We appreciate the comments of Sempsrott et al 1 regarding the article “Flush Drowning as a Cause of Whitewater Deaths” 2 and find their observations terminologically insightful. We agree that adding qualifiers to the term drowning, such as “dry, secondary, or near” sometimes adds more confusion than clarity. Our use of “flush drowning” deviates from the current definition of “drowning” in several respects; for instance, flush drowning in our definition is always fatal, whereas most uses of the word “drowning” involve variable outcomes. Human death most often is influenced by preexisting comorbidities that may interact with various triggering or enhancing environmental precipitants, any of which may or may not be anticipated or recognized by a medical examiner. Diagnostic uncertainty exists in many deaths, and in the case of lethal drowning, pathologists recognize the inherent risk of missing important confounders, such as seizures, intoxicants, trauma, or hypothermia. 3 –5
Although we agree with most of the statements of Sempsrott et al, we would like to make several other comments regarding the letter. First, our usage of the term “flush drowning” was driven primarily by its long-standing prior establishment and name recognition within the whitewater community, which is our target audience. As for the general suitability of the phrase in the medical literature, not only does use of “drowning” rightly raise questions, but the qualifier “flush” is even more problematic because it implies that flush drownings only occur in “flushing” flows, which is incorrect. In fact, it is our opinion that water temperature has a profound effect on flush drowning.
Second, because drowning definitions variably refer to immersion or submersion in a liquid medium with respiratory impairment as required substrates, most lack further specificity as to the antecedents leading to respiratory compromise. In fatal drownings, many current definitions, taken literally, could suggest any “in water” death is a drowning, considering that all death involves respiratory impairment. Although this may or may not be the intention of the epidemiologists, such an application does little to differentiate the primary or sequential physiologic events leading to respiratory compromise. In regard to cold water immersion, we have suggested lethal arrhythmias may be an important cause of death. As such, if the head is never submersed and there is no head-above-water aspiration, the respiratory compromise could be a secondary effect of immersion-produced arrythmia. Other similar potentially lethal effects of cold-water immersion that do not necessarily require aspiration or head submersion may include hypothermia, hypertension-induced vascular catastrophe, and post-rescue collapse. Although such events may still be considered a drowning in the strictest sense, preventing adverse outcomes may require varied approaches.
Lastly, the suggestion by Sempsrott et al that flush drownings be called “fatal drowning due to X,” where “X” presumably represents the antecedent cause of the drowning, may be attractive in certain applications, but such phrasing would be largely a semantic gesture as applied to flush drowning. Until we can differentiate which deaths in this cohort directly result from cold water immersion versus other causes, X will remain elusive. This confusion is further compounded because secondary submersion or aspiration events can follow any cause of death. These constructs have always presented problems for physicians signing death certificates.3,5 For instance, does the fisherman who is standing in knee-deep water and is fatally struck by lightning represent a fatal drowning secondary to lightning strike? Does this hold true even if the victim’s head never becomes submersed and no aspiration occurs? Likewise, does the deceased jogger found face up in 10 cm (4 in) of water with an intoxicant in the bloodstream represent drowning or something else? With respect to flush drowning, because of the inability to reliably define X, we arrive back at “fatal drowning due to flush drowning,” or whatever phrase one decides to call this amorphous group. Although we agree new terminology is required, until we can reliably differentiate X, this effort may offer little enlightenment, although it may appease the semasiologists.