Saltwater Drowning Research Articles

Distinction between saltwater drowning and freshwater drowning by assessment of sinus fluid on post-mortem computed tomography.

To evaluate the difference in sinus fluid volume and density between saltwater and freshwater drowning and diagnose saltwater drowning in distinction from freshwater drowning. Ninety-three drowning cases (22 saltwater and 71 freshwater) were retrospectively investigated; all had undergone post-mortem CT and forensic autopsy. Sinus fluid volume and density were calculated using a 3D-DICOM workstation, and differences were evaluated. Diagnostic performance of these indicators for saltwater drowning was evaluated using a cut-off value calculated by receiver operating characteristic (ROC) analysis. The median sinus fluid volume was 5.68 mL in cases of saltwater drowning (range 0.08 to 37.55) and 5.46 mL in cases of freshwater drowning (0.02 to 27.68), and the average densities were 47.28 (14.26 to 75.98) HU and 32.56 (-14.38 to 77.43) HU, respectively. While sinus volume did not differ significantly (p = 0.6000), sinus density was significantly higher in saltwater than freshwater drowning cases (p = 0.0002). ROC analysis for diagnosis of saltwater drowning determined the cut-off value as 37.77 HU, with a sensitivity of 77 %, specificity of 72 %, PPV of 46 % and NPV of 91 %. The average density of sinus fluid in cases of saltwater drowning was significantly higher than in freshwater drowning cases; there was no significant difference in the sinus fluid volume. • Sinus fluid density of saltwater drowning is significantly higher than freshwater drowning. • Cut-off value was 37.77 HU based on the ROC analysis. • The cut-off value translated to 91 % NPV for diagnosis of saltwater drowning.

Forensic application of microRNA-706 as a biomarker for drowning pattern identification

Forensic research using microRNA has been used so far only for the identification of body fluids, but its use in understanding biological processes in post-mortem pathology has not been studied before. Therefore, we performed experiments in mice to compare between freshwater and saltwater drowning models, and miRNA expression was analyzed in the brain through a forward bioinformatics screening approach. In this study, we identified eight specific microRNAs whose expression increased in freshwater and decreased in saltwater. Among them, miR-706 – targeting HCN1 – was identified as a potent biomarker for the drowning pattern identification. A higher expression of miR-706 was detected in the freshwater drowning compared to the control and saltwater drowning group (p<0.05, and p<0.01, respectively). HCN1 mRNA expression, a suggested candidate target for miR-706, was lower in the freshwater (p<0.01) than in the saltwater drowning group, and showed statistical difference between freshwater and saltwater drowning (p<0.01). miR-706 was specifically expressed in the hippocampal neurons as detected by in situ hybridization. Our data suggest that a specific microRNA may provide clues to understanding some crime scene investigations and pathobiological processes in the dead body.

Iatrogenic salt water drowning and the hazards of a high central venous pressure.

Current teaching and guidelines suggest that aggressive fluid resuscitation is the best initial approach to the patient with hemodynamic instability. The source of this wisdom is difficult to discern, however, Early Goal Directed therapy (EGDT) as championed by Rivers et al. and the Surviving Sepsis Campaign Guidelines appears to have established this as the irrefutable truth. However, over the last decade it has become clear that aggressive fluid resuscitation leading to fluid overload is associated with increased morbidity and mortality across a diverse group of patients, including patients with severe sepsis as well as elective surgical and trauma patients and those with pancreatitis. Excessive fluid administration results in increased interstitial fluid in vital organs leading to impaired renal, hepatic and cardiac function. Increased extra-vascular lung water (EVLW) is particularly lethal, leading to iatrogenic salt water drowning. EGDT and the Surviving Sepsis Campaign Guidelines recommend targeting a central venous pressure (CVP) > 8 mmHg. A CVP > 8 mmHg has been demonstrated to decrease microcirculatory flow, as well as renal blood flow and is associated with an increased risk of renal failure and death. Normal saline (0.9% salt solution) as compared to balanced electrolyte solutions is associated with a greater risk of acute kidney injury and death. This paper reviews the adverse effects of large volume resuscitation, a high CVP and the excessive use of normal saline.

Elevated Postmortem Vitreous Sodium and Chloride Levels Distinguish Saltwater Drowning (SWD) Deaths From Immersion Deaths Not Related to Drowning But Recovered From Saltwater (DNRD)

A 5-year prospective study of saltwater-related deaths was undertaken in 2 medico-legal centers in Australia. This demonstrated a statistically significant elevation (P<0.01) in postmortem vitreous sodium and chloride (PMVSC) levels and sum of sodium and chloride levels in 15 cases of deaths due to saltwater drowning (SWD) in comparison with 7 immersion deaths not related to drowning but recovered from saltwater (DNRD), and with 50 case controls. From our data, PMVSC was superior to using sodium or chloride levels alone in discriminating SWD from DNRD and controls. It is proposed that in cases where bodies are retrieved from a saltwater environment and SWD is suspected, a PMVSC of 284 mmol/L or higher is consistent with SWD. Conversely, a PMVSC level of less than 258 mmol/L is inconsistent with SWD. A PMVSC between 258 and 284 mmol/L is inconclusive or noninformative, and circumstantial evidence and autopsy findings are needed to determine the cause of death. It is suggested that PMVSC measurement is a worthwhile test in determining the cause of death in cases where bodies are recovered from saltwater, especially in cases where an internal examination of the body may not be authorized or where objections to autopsy are upheld.

Diagnostic Value of Cardiac Troponin I in Postmortem Diagnosis of Myocardial Infarction

Troponin I (cTnI) is a very sensitive biochemical marker for the diagnosis of myocardial infarction (MI). Cardiac troponin (cTnI or cTnT) has nearly absolute myocardial tissue specificity, thereby reflecting even microscopic zones of myocardial necrosis. The aim of this study is to evaluate the pericardial fluid levels of cTnI in medicolegal autopsy cases where patients died of MI and compare them with cases where patients died of other causes. This study included 89 cases selected during a 1-year period from medicolegal autopsies. These were classified into 4 groups: (A) myocardial infarction (n = 28), (B) salt water drowning (n = 20), (C) death resulting from injury in the respiratory system (n = 16), and (D) other causes of death (n = 25), excluding MI. The mean concentrations of cTnI were 1067.03 mg/dL for group A, 546.98 mg/dL for group B, 398.75 mg/dL for group C, and 577.47 mg/dL for group D. In cases with MI (group A), there was a significant difference in the levels of cTnI compared with the other cases. More research needs to be done in order for a cutoff level to be determined.

Drowning related out-of-hospital cardiac arrests: Characteristics and outcomes

AimThere are few studies on drowning-related out-of-hospital cardiac arrest (OHCA) in which patients are followed from the scene through to hospital discharge. This study aims to describe this population and their outcomes in the state of Victoria (Australia). MethodsThe Victorian Ambulance Cardiac Arrest Registry was searched for all cases of OHCA with a precipitating event of drowning attended by emergency medical services (EMS) between October 1999 and December 2011. ResultsEMS attended 336 drowning-related OHCA during the study period. Cases frequently occurred in summer (45%) and the majority of patients were male (70%) and adult (77%). EMS resuscitation was attempted on 154 (46%) patients. Of these patients, 41 (27%) survived to hospital arrival and 12 (8%) survived to hospital discharge (5 adults [6%] and 7 [12%] children). Few patients were found in a shockable rhythm (6%), with the majority presenting in asystole (79%) or pulse-less electrical activity (13%). An initial shockable rhythm was found to positively predict survival (AOR 48.70, 95% CI: 3.80–624.86) while increased EMS response time (AOR 0.73, 95% CI: 0.54–0.98) and salt water drowning (AOR 0.69, 95% CI: 0.01–0.84) were found to negatively predict survival. ConclusionsRates of survival in OHCA caused by drowning are comparable to other OHCA causes. Patients were more likely to survive if they did not drown in salt water, had a quick EMS response and they were found in a shockable rhythm. Prevention efforts and reducing EMS response time are likely to improve survival of drowning patients.

Lethal fish hook attachment – An unusual occurrence

A 39-year-old fisherman is reported who was dragged into the water from a boat after he became entangled in fishing line. His death was attributed to salt water drowning. At autopsy the cause of death was confirmed and the mechanism of the lethal event elucidated. Specifically, a large fish hook attached to line was embedded in his right wrist. The hook had passed beneath flexor tendons and had firmly attached him to fishing line that was being dropped from the vessel. There were no other significant injuries or underlying diseases present. This case demonstrates another rare situation in the commercial fishing industry that may result in a victim being dragged from a boat and drowned.

Vitreous Humor Sodium Levels in Immersion Deaths

To determine whether vitreous humor sodium levels might be of use in evaluating deaths associated with immersion, samples of vitreous humor were prospectively evaluated at autopsy over a 4-year period from 2006 to 2009. There were 19 cases of saltwater immersion (age range 9-76 years; mean age 44 years; M:F, 2.8:1) and 16 freshwater immersions (age range 2-81 years; mean age 27 years; M:F, 2.2:1). In the group of saltwater drownings, vitreous humor sodium levels were elevated, ranging from 145 to 184 mM (mean = 160.2 ± 9.9 mM), and in the cases of freshwater drowning, the levels were reduced, ranging from 73 to 148 mM (mean = 129.8 ± 17 mM; p < 0.0001). Alterations in electrolyte levels may have been because of hemoconcentration or dilution from electrolyte fluxes in the lungs, or from passive diffusion during immersion. This study has demonstrated that vitreous sodium level is an easily performed test that may be a useful adjunct to the investigation of possible immersion deaths.

Post-mortem vitreous sodium and chloride levels – a biochemical test for salt water drowning?

Deaths due to drowning, in both salt and fresh water, are quite frequently encountered in forensic pathology practise. A diagnosis of drowning may be made when other causes of death from trauma, drugs, natural disease, etc, have been excluded after a body is retrieved from water and examined. These types of cases can be difficult for the pathologist, especially when factors such as absence of witnesses to the event, prolonged immersion time, and/or decomposition occur. Post-mortem changes may significantly alter the integrity of the body and affect opinions relating to the cause and time of death. Eleven cases of salt water drowning are presented, where vitreous sodium and chloride levels have been tested for post-mortem. In 10 out of 11 cases, there was a statistically significant elevation of the sodium and chloride levels, in comparison with 35 case controls. It is proposed that post-mortem vitreous sodium and chloride testing could be used as an adjunct to the autopsy in the investigation of death from presumed salt water drowning. If the post-mortem vitreous sodium + chloride levels exceed 280–290 mmol/L, a cause of death from salt water drowning would appear quite likely, if circumstances surrounding the death and autopsy findings also suggest drowning as a likely cause of death.

Immunohistochemical examination of intracerebral aquaporin-4 expression and its application for differential diagnosis between freshwater and saltwater drowning

Human brain samples were collected from 70 autopsy cases including 22 freshwater drowning (FWD), 26 saltwater drowning (SWD), and 22 non-drowning cases as controls. Then, immunohistochemical study combined with morphometry was carried out in order to examine the differential expression of AQP1 and AQP4 in the brain samples. Immunohistochemically, star-shaped cells bearing highly branched processes, often surrounding blood vessels, showed positive reactions for AQP1 and AQP4 in FWD, SWD, as well as control groups. Additionally, with double-color immunofluorescence analysis, AQP1- or AQP4-positive cells could be identified as GFAP-positive astrocytes. Moreover, AQP1-positive reaction was also observed in blood vessels. Morphometrically, there were no significant differences in AQP1 expression in astrocytes or in blood vessels among the three groups. In contrast, the average value of AQP4-positive astrocytes was significantly higher in FWD cases than in SWD and control groups. Moreover, AQP4 expression was significantly lower in SWD than in the control group (p < 0.05). Moreover, there was no significant correlation between post-submerged interval and AQP expression in drowning cases. Therefore, immunohistochemical analysis of intracerebral AQP4 expression would be forensically useful for differentiation between FWD and SWD.

Forensic application of intrarenal aquaporin-2 expression for differential diagnosis between freshwater and saltwater drowning

Aquaporins (AQPs) are a family of homologous water channel proteins. In this study, the expressions of AQP1, 2, and 4 were immunohistochemically examined in kidney samples to evaluate their forensic applicability to differentiate between freshwater drowning (FWD) and saltwater drowning (SWD). Kidney samples were obtained from 51 drowning cases (23 FWD and 28 SWD) and 19 non-drowning cases. AQP1 was expressed in the proximal tubules and glomeruli, and AQP4 was localized in the collecting ducts. However, there were no significant differences in AQP1 and AQP4 expressions among FWD, SWD, and control groups. Immunohistochemically, AQP2 was predominantly expressed in the apical plasma membrane of the collecting duct principal cells in all kidney samples of FWD and SWD. Morphometrically, AQP2 expression at the apical plasma membrane of collecting ducts was significantly enhanced in SWD group, compared with FWD and control groups. On the other hand, AQP-2 expression was significantly lower in FWD group than in control group. Moreover, in drowning cases, there was no correlation between post-submersion intervals and AQP expression. From a forensic aspect, immunohistochemical detection of AQP2 in the kidney can be considered a valuable marker to differentiate between FWD and SWD.

Evaluation of pulmonary GLUT1 and VEGF mRNA levels in relation to lung weight in medicolegal autopsy cases

The present study focuses attention upon the relationship among postmortem mRNA levels of pulmonary glucose transporter (GLUT1) and vascular endothelial growth factor (VEGF) to lung weight to investigate pulmonary pathophysiology in the death process. Autopsy cases ( n = 173, within 48 h postmortem) of blunt injury, including head injury (brain contusions and acute subdural hemotoma) and non-head injury, sharp instrument injury, mechanical asphyxiation, drowning, acute myocardial infarction/ischemia (AMI) and idiopathic cerebral hemorrhage (ICH) were examined. GLUT1 and VEGF mRNAs were quantified by TaqMan real-time RT-PCR for the upper lobes of the bilateral lungs. Combined lung weight was normalized against height for statistical analyses. GLUT1 mRNA showed a higher level for ICH. GLUT1 and VEGF mRNA levels were higher for brain contusions than for acute subdural hematoma, which showed a significantly lower VEGF mRNA level. Lung weight showed a larger value for saltwater drowning and ICH, and was larger for acute subdural hematoma than for brain contusions. GLUT1 mRNA level was correlated with lung weight in cases of ICH and brain contusions (survival time <24 h), and VEGF mRNA showed a similar tendency. Such findings were not detected for other groups. These findings indicate parallel increases in hypoxia-induced responses and lung weight in ICH and brain contusions, suggesting different pulmonary hemodynamics with milder alveolar damage compared with other groups, including AMI and acute subdural hematoma. Different mechanisms might be involved in non-cardiogenic or neurogenic pulmonary congestion and edema for ICH/brain contusions and subdural hematoma.

Analysis of postmortem biochemical findings with regard to the lung weight in drowning

To clarify drowning death, positive evidence for aspiration of the immersion medium and the subsequent fatal mechanism is necessary. This study investigated biochemical findings with regard to lung weight in drowning cases of adults ( n = 56, >18 years of age, <48 h postmortem: salt water, n = 19; fresh water, n = 21; brackish water, n = 16), using acute cardiac death cases ( n = 240) as controls. The biochemical markers used in this study were urea nitrogen (UN), sodium (Na), chloride (Cl), calcium (Ca) and magnesium (Mg) in the blood and pericardial fluid (PCF). The left-to-right ratio of cardiac blood UN levels was lower for drowning, showing an inverse correlation to the total lung weight. There was a mild postmortem decrease in serum and PCF Na and Cl levels; however, left cardiac serum and PCF Na, Cl, Ca and Mg levels were higher for saltwater drowning, and left cardiac serum Na and Cl levels were lower for fresh water drowning. Correlation of the left cardiac serum level with lung weight was positive for Na, Cl and Mg in saltwater and brackish water drowning, and was also positive for Ca in saltwater drowning. There was an inverse correlation with lung weight for PCF Na and Cl levels in freshwater drowning. These findings suggest that analyses of serum and pericardial markers in relation to lung weight are useful for evaluating the composition and amount of aspirated medium when investigating drowning death.

Evaluation of postmortem calcium and magnesium levels in the pericardial fluid with regard to the cause of death in medicolegal autopsy

Previous studies have suggested the usefulness of postmortem serum calcium (Ca) and magnesium (Mg) for investigating cause of death. The present study investigated their levels in the pericardial fluid of serial autopsy cases of adults within 48 h postmortem ( n = 385), including fatalities from blunt injury ( n = 57), sharp instrument injury ( n = 9), mechanical asphyxiation ( n = 28), salt- and freshwater drowning ( n = 14 and n = 61, respectively), fire fatality ( n = 35), intoxication ( n = 23), hypothermia (cold exposure, n = 12), hyperthermia (heat stroke, n = 7), acute cardiac death (ACD, n = 86), pneumonia ( n = 9) and spontaneous cerebral hemorrhage ( n = 11). The pericardial Ca level was independent of the postmortem interval, showing a value similar to that of the clinical reference range in cases other than saltwater drowning, while the Mg level was higher than the clinical reference range and showed a mild postmortem time-dependent increase. Pericardial Ca was significantly higher for saltwater drowning than other groups, and a lower level was seen for hyperthermia, and some cases of blunt injury and intoxication. The Mg level was also significantly higher for saltwater drowning than the other groups, and showed a higher level for sharp instrument injury, but a lower level for hypothermia. The Mg/Ca ratio was higher for sharp instrument injury and saltwater drowning, but was lower for hypothermia. These findings suggest that postmortem pericardial Ca and Mg can be used to investigate the cause of death, especially for saltwater drowning, hypothermia and hyperthermia.

Differential diagnosis between freshwater drowning and saltwater drowning based on intrapulmonary aquaporin-5 expression

The intrapulmonary expression of aquaporin-5 (AQP5) was examined in an experimental drowning model and forensic autopsy cases to discuss the possibility for differentiation between freshwater drowning (FWD) and saltwater drowning (SWD). In animal experiments, mice were classified into four groups: (group I: FWD; group II: SWD; group III: postmortem immersion (PI); and group IV: cervical dislocation as controls. In group I, intrapulmonary AQP5 expression was significantly suppressed at both gene and protein levels, compared with the other three groups, and there was no significant difference in AQP5 expression among groups II to IV. In the next series, we examined AQP5 gene expression in human lung samples obtained from forensic autopsies at less than 48 h postmortem (nine FWD cases, five SWD cases, and 14 other cases). Although AQP5 mRNA could be detected in all lung samples under the employed experimental conditions, the intrapulmonary gene expression of AQP5 in FWD was significantly attenuated compared with the other groups. These observations imply that AQP5 expression in type I alveolar epithelial cells was suppressed by hypotonic water to prevent hemodilution from the physiological aspect. Moreover, the analysis of intrapulmonary AQP5 expression would be forensically useful for differentiation between FWD and SWD, or between FWD and PI.

Haemolytic staining of the intima of the aortic root – A useful pathological marker of freshwater drowning?

The significance of haemolytic staining of the aorta is unclear. While it has been associated with freshwater drowning, data are lacking. To study this phenomenon further a prospective study looking at the colour of the intima of the pulmonary trunk and aortic root was undertaken in 47 randomly selected coronial control cases and in 13 consecutive fresh drowning deaths. There were 16 putrefied control cases each of which showed haemolytic staining of both great vessels. Of the other 44 non-putrefied cases (31 controls, 9 saltwater drownings, and 4 freshwater drownings), only one (a freshwater drowning) showed marked staining of the aortic root with no staining of the intima of the pulmonary trunk. Conclusion: This study has demonstrated that haemolytic staining of the aorta at autopsy, in the absence of significant staining of the pulmonary trunk and putrefaction, may be a pathological feature that is supportive of freshwater drowning. It is not, however, present in all cases. Given the relatively small numbers in this study further work is required to clarify this issue.

Drowning, haemodilution, haemolysis and staining of the intima of the aortic root – preliminary observations

In order to demonstrate that hyponatraemia due to haemodilution occurs within the left ventricle following freshwater drowning, and to determine whether lysed blood resulting from left ventricular haemodilution may cause staining of the aortic intima, the following studies were undertaken. Measurements of left ventricular sodium levels were performed in 74 consecutive coronial cases where death was attributed to drowning, consisting of 44 and 30 deceased who were believed to be victims of freshwater and saltwater drowning, respectively. Left ventricular sodium levels differed significantly between the two groups ( p < 0.001), with a range of 93–147 mmol/L in freshwater drowning (mean = 117 ± 14.2 mmol/L) and 123–183 in saltwater drowning (mean = 153 ± 14.4 mmol/L). In addition, the mean sodium level of 117 mmol/L in freshwater drowning was significantly lower than the standard range of 137–145 mmol/L. In a second study, portions of aorta and pulmonary trunk from a euthanised pig were soaked in lysed blood resulting in marked haemolytic staining of the intima of both vessels after 20 min. Water and a mixture of blood and water were then injected into the left ventricles in two further pig carcasses, respectively, resulting in haemolytic staining of the intima of the aortic roots, with no staining of the pulmonary trunks. These studies have confirmed that significant hyponatraemia secondary to haemodilution may occur within the left ventricle in freshwater drowning, and that haemolysed blood is capable of causing staining of the aortic root in an animal model. These results provide further data to support haemolytic staining of the aortic root intima as a possible manifestation of freshwater drowning.

Quantitative analysis of ubiquitin-immunoreactivity in the midbrain periaqueductal gray matter with regard to the causes of death in forensic autopsy

The aim of the present study was to examine Ub-immunoreactivity in the midbrain periaqueductal gray matter (PGM), which is involved in pain processing and modulation, in forensic autopsy cases ( n=273) in relation to the causes of death: acute deaths from blunt injuries ( n=75), sharp weapon injuries ( n=36), fatal asphyxiation ( n=22), drownings ( n=16: freshwater, n=9; saltwater, n=7), fire fatalities ( n=64), poisoning ( n=12), hyperthermia ( n=5), hypothermia ( n=5), delayed deaths from blunt head injury ( n=8), acute cardiac deaths ( n=24), and acute cerebrovascular strokes ( n=6). The Ub-immunoreactivity was clearly observed in the nuclei of the PGM neurons, showing no postmortem interference or age-dependency. A higher value was observed in blunt injuries, fire fatalities and also in saltwater drowning, hyperthermia and delayed head injury deaths. These findings suggest a complicated mechanism for the ubiquitination of PGM neurons, to which multiple factors including the intensity and duration of pains possibly under alert consciousness, traumatic and metabolic neurodegeneration may contribute.

Pleural effusion in bodies recovered from water

Both in saltwater and freshwater drowning cases, a common autopsy sign is pleural effusion. However, the factors that determine the amount of pleural effusion have not been well established. An attempt was therefore made to correlate the amount of pleural fluid in bodies recovered from water with several parameters registered on the judicial files as well as autopsy findings from the years 1994–1998. The number of cases with pleural fluid increase was found to be very high in saltwater drowning ( P<0.001). But, when the freshwater and saltwater drowning cases with pleural fluid increase were compared according to pleural fluid amount, no significant difference was detected (521±340 and 768±536 ml, respectively). Although there was a positive correlation between the decomposition degree and the fluid in the pleural cavity, a relative decrease was detected in the amount of effusion contrary to the expectations in cases of extreme decomposition. Pleural fluid amount provides significant data about the type of water and the cause of death in early postmortem interval. And there is a link between the time spent in water and the amount of pleural effusion. With the advance of the postmortem interval, decomposition level and the duration of immersion should be taken into account in differential diagnosis.

Postmortem lung weight in drownings: a comparison with acute asphyxiation and cardiac death

There are several controversial findings and arguments about the lung weight as a marker of drowning. The aim of the present study was to examine the difference in the lung weight and the amount of pleural effusion between freshwater and saltwater drownings ( n=70 and n=75, respectively), in comparison with asphyxiation ( n=85) and acute cardiac death ( n=82), for the diagnosis of drowning. In drowning cases, a gradual postmortem time-dependent decrease in the lung weight and a reciprocal increase in the pleural effusion suggested postmortem transudation from the lungs. The decrease in the total value of the combined lung weight and the amount of pleural effusion was marked in saltwater immersion after 3 days postmortem, suggesting a leakage of the effusion out of the thoracic cavity under an osmotic effect of the immersion medium. In cases within 3 days postmortem, when the combined lung weight and amount of pleural effusion were added to estimate possible combined lung weight at the time of death, there was a gross difference among the causes of death: the value was the largest in saltwater drowning, followed by freshwater drowning, acute cardiac death and asphyxiation. However, the value depended on the gender and age of the subjects, suggesting a relation to the individual physical constitution and survival time or vital activity. These factors should be taken into consideration in evaluation of the lung weight in the diagnosis of drownings.