Effect of intravenous vs. aspirated distilled water on serum electrolytes and blood gas tensions

The Forensic Pathology of Drowning and Pulmonary Overexpansion Injury

Drowning deaths are commonly seen in most forensic pathology practices. Experienced forensic pathologists perform autopsies and assign a cause and manner of death in such cases as a matter of routine. Deaths due to pulmonary overexpansion injury and subsequent air embolism are far less common and typically involve individuals who have been breathing compressed gas at depth, generally SCUBA (self-contained underwater breathing apparatus) divers. This review outlines the pathophysiological basis of these two forensic pulmonary issues and recommends an approach to performing and interpreting the results of a forensic autopsy when faced with such cases.

Drowning

PURPOSE OF REVIEW

To summarize current knowledge on pathophysiology and treatment of drowning accidents. Studies and case reports were searched using the keywords drowning, near-drowning, asphyxia, hypoxia and hypothermia in conjunction with organ systems and specific treatment options.

RECENT FINDINGS

Drowning is defined as death by suffocation in a liquid. In contrast, near-drowning is defined as survival beyond 24 h after a drowning accident. Drowning is a frequent preventable accident with a significant morbidity and mortality in a mostly healthy population. In the majority of patients the primary injury is pulmonary, resulting in severe arterial hypoxemia and secondary damage to other organs. Damage to the central nervous system is most critical in terms of patient survival and subsequent quality of life. Therefore, prompt resuscitation and aggressive respiratory and cardiovascular treatment are crucial for optimal survival. Immediate interruption of hypoxia, aggressive treatment of hypothermia and cardiovascular failure are the cornerstones of correct medical treatment. Unfortunately, accurate neurologic prognosis cannot be predicted from initial clinical presentation, laboratory, radiological or electrophysiological examinations.

SUMMARY

Several case studies have convincingly demonstrated that drowning victims may survive neurologically intact even after prolonged submersion times, in particular in cold water. Therefore, aggressive initial therapeutic efforts are indicated in most near-drowning victims.

Electrolyte analysis in pleural effusion as an indicator of the drowning medium

In medico-legal autopsies for drowned bodies, the location of drowning needs to be determined. To investigate the usefulness of electrolyte analysis in pleural effusion as an indicator of the location where the deceased has drowned, we determined the concentrations of electrolytes in the pleural effusion of rats drowned in four kinds of water. The concentrations of sodium and chloride ions in the pleural effusion of rats that drowned in seawater were significantly greater than those of rats that drowned in freshwater at both 1 day and 3 days after drowning. The concentration of potassium ions in pleural effusion 1 day after drowning showed no difference between each group, although it then increased from 1 to 3 days after seawater drowning, whereas it decreased from 1 to 3 days after freshwater drowning. The concentration of total protein in pleural effusion increased from 1 to 3 days after drowning, however, there was no significant difference in the concentration of total protein in pleural effusion between each group at either 1 day or 3 days after drowning. These results suggest that analysis of electrolytes in pleural effusion may be useful for determining whether drowning has occurred in seawater or in freshwater.

What Is the Incidence and Significance of “Dry-Lungs” in Bodies Found in Water?

BACKGROUND

Drowning without aspiration of liquid, generally attributed to death from asphyxia while submerged and in laryngospasm, has been reported to occur in approximately 10% to 15% of drowning victims.

OBJECTIVES

The occurrence of "dry-drowning" recently has been questioned and the hypothesis developed that "dry-lungs" in bodies found dead in the water could conceal more natural deaths than previously recognized.

METHODS

Based on 578 selected adult victims who presumably drowned, we analyzed the correlation between the cases with a low combined lung/pleura liquid weight (< 1000 g and < 750 g) and a wide set of individual, circumstantial, and postmortem (PM) variables, using multivariate logistic regression analysis. Victims with lung weight < 1000 g were screened for long-QT syndrome (LQTS) founder mutations in KCNQ1 and KCNH2 genes.

RESULTS

Of the 578 victims, 120 (20.7%) had a lung weight of < 1000 g, and 22 of these (3.8%) of < 750 g. Multivariate analysis showed a significant correlation for women (P < 0.001), for women aged 65 years or older (P < 0.001), and for men with prolonged PM submersion time (P < 0.001). "Normal" lungs were found in only 8 (1.4%) victims. Low-weight (< 1000 g), overdistended lungs with no sign of liquid penetration were seen in 11 (1.9%). No LQTS founder mutations were detected.

CONCLUSIONS

The actual incidence of death of persons found in water who have normal lungs or do not have penetration of liquid into their airways, based on our study, is much lower (below 2%) than currently assumed.

Survival after prolonged submersion in freshwater in Florida

A 2-year-old boy was submerged for at least 20 min in a freshwater creek in Union County, FL. Cardiopulmonary resuscitation (CPR) was administered for approximately 1 h at the scene and during transport to the hospital. On arrival, his Glasgow coma scale score was 3 and rectal temperature was < or = 26.7 degrees C. He demonstrated respiratory failure, intense vasoconstriction, hemoglobinuria, anemia, hypercoagulability, thrombocytosis, leukopenia, and persistent coma. With intensive care, he began emerging from the coma after 72 h and progressively improved. Testing at the Developmental Evaluation Center and clinical observations showed him to be completely normal by 6 months after drowning. Thus, severe, rapid hypothermia can occur during drowning in cold water in any geographic location and at temperatures above those necessary for ice formation. Hypothermia provides cerebral protection from hypoxia, permitting total recovery with appropriate CPR and intensive care.

Drowning and near-drowning

Water immersion is a frequent cause of accidental death and hospital admission. This article outlines the pathogenesis and principles of treatment. Drowning is defined as death by asphyxia due to submersion in a liquid medium. Near-drowning is defined as immediate survival after asphyxia due to submersion.

A canine study of cold water drowning in fresh versus salt water

OBJECTIVE

To compare the pathophysiologic changes occurring during drowning in cold fresh water and cold salt water with reference to viability.

DESIGN

Randomized, prospective, controlled submersion experiments in two contrasting cold liquids.

SETTING

A laboratory at a large university-affiliated medical institution.

SUBJECTS

Thirteen healthy, anesthetized mongrel dogs. Three dogs served as controls and were immersed but not submerged. The remainder were submerged in cold fresh water or cold salt water (4 degrees C).

INTERVENTIONS

Catheters were placed in the femoral artery, right carotid artery and right internal jugular vein. Electrocardiogram, pneumogram, and rectal temperatures were measured continuously during submersion/immersion.

MEASUREMENTS AND MAIN RESULTS

Cold water submersion with drowning produced a large initial decrease in carotid artery temperature (approximately 7.5 degrees C in the first 2 mins) compared with a minor decrease (approximately 0.8 degrees C with immersion). No significant differences were noted in the rate of decrease of temperature between drowning in fresh water and salt water. During cold fresh water drowning, aspiration produced gross hemodilution with an average increase in body weight of 16.5%. Hematocrit values, serum sodium concentrations, and osmolality decreased while serum potassium concentrations, catecholamines, and free hemoglobin increased. All measured biochemical data (except PaO2) remained at viable levels. By contrast, during cold salt water drowning, average body weight increased by only 6%, with hemoconcentration and a shrinkage of vascular volume. Hematocrit and hemoglobin values increased by 30%, but initial plasma free hemoglobin values remained unchanged. Serum sodium concentrations, osmolality, and potassium concentrations increased rapidly to critical levels.

CONCLUSIONS

On submersion in cold water, all of the experimental animals developed tachypnea immediately, followed by aspiration with predictable effects. The biochemical and pathophysiologic changes in cold water drowning approximated those changes reported for warm water drowning for both fresh and salt water with one exception and continued aspiration of cold water produced extremely rapid core cooling as long as the circulation remained intact. This process of acute submersion hypothermia may protect the brain temporarily from lethal damage, as reported in cases of cold fresh water drowning. Concentrations of circulating catecholamines increased exponentially in both groups of test animals. Clinically, their acute effects on the circulation, compounded by significant hypothermia and extreme anoxia, must hamper the detection of residual circulation at rescue and may play a role in sudden death from cold water in the absence of drowning.

Clinical course of 91 consecutive near-drowning victims

Hospital records of 91 consecutive near-drowning victims were studied retrospectively. Eight-one (89 percent) of these patients survived. Patients who were alert on arrival at the emergency room survived, but those who were comatose and had fixed dilated pupils died. Other states of consciousness were unreliable predictors of survival. All patients with a normal chest roentgenogram on admission survived; however, values for arterial oxygen tension (PaO2) did not necessarily correlate with the chest roentgenograms. Values for arterial blood gas tensions and pH varied widely, as follows; PaO2, 25 to 465 mm Hg; arterial carbon dioxide tension (PaCO2), 17 to 100 mm Hg; pH, 6.77 to 7.50; and arterial bicarbonate level, 6.6 to 29.7 mEq/L. The ratio of PaO2 to the fractional concentration of oxygen in the inspired gas (FIo2), which was calculated to standardize PaO2 data for varying concentrations of inspired oxygen, ranged from 30 to 585 mm Hg. Only one patient with a ratio of PaO2/FIo2 greater than 150 mm Hg on admission subsequently died; this was a neurologic rather than a pulmonary death. Serum electrolytic concentrations and values for hemoglobin level and hematocrit reading neither predicted survival nor indicated that a threat to life existed. Steroid and prophylactic antibiotic therapy did not appear to increase the chance of survival. Observations on these patients are discussed in light of previous experiments in animals, and an approach to therapy is suggested.