The effects of fluid volume in seawater drowning

Wilderness Medical Society Clinical Practice Guidelines for the Treatment and Prevention of Drowning: 2024 Update

The Wilderness Medical Society convened a panel to review available evidence supporting practices for acute management of drowning in out-of-hospital and emergency care settings. Literature about definitions and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking. This is the second update to the original practice guidelines published in 2016 and updated in 2019.

Management for the Drowning Patient

Drowning is "the process of experiencing respiratory impairment from submersion or immersion in liquid." According to the World Health Organization, drowning claims the lives of > 40 people every hour of every day. Drowning involves some physiological principles and medical interventions that are unique. It occurs in a deceptively hostile environment that involves an underestimation of the dangers or an overestimation of water competency. It has been estimated that > 90% of drownings are preventable. When water is aspirated into the airways, coughing is the initial reflex response. The acute lung injury alters the exchange of oxygen in different proportions. The combined effects of fluid in the lungs, loss of surfactant, and increased capillary-alveolar permeability result in decreased lung compliance, increased right-to-left shunting in the lungs, atelectasis, and alveolitis, a noncardiogenic pulmonary edema. Salt and fresh water aspirations cause similar pathology. If the person is not rescued, aspiration continues, and hypoxemia leads to loss of consciousness and apnea in seconds to minutes. As a consequence, hypoxic cardiac arrest occurs. The decision to admit to an ICU should consider the patient's drowning severity and comorbid or premorbid conditions. Ventilation therapy should achieve an intrapulmonary shunt ≤ 20% or Pao₂:Fio₂ ≥ 250. Premature ventilatory weaning may cause the return of pulmonary edema with the need for re-intubation and an anticipation of prolonged hospital stays and further morbidity. This review includes all the essential steps from the first call to action until the best practice at the prehospital, ED, and hospitalization.

Drowning in Children: Retrospective Analysis of Incident Characteristics, Predicting Parameters, and Long-Term Outcome

BACKGROUND

Drowning is the second leading cause of unnatural death in childhood worldwide. More than half of the drowned children, who were in need of cardiopulmonary resuscitation (CPR) at the scene suffered from lifelong neurological sequelae. There are few data about prognostic predictors in the pediatric population of drowning victims. The objective of the study was to assess incident characteristics, prognostic parameters, and long-term outcome of children recovering from a drowning incident.

METHODS

We carried out a retrospective analysis of data of the cohort of pediatric cases (age 0-18) of drowning victims admitted in the years 2000-2015 to the emergency room/intensive care unit/pediatric ward at the University Children's Hospital of Zurich, Switzerland. Outcome was classified by the Pediatric Cerebral Performance Category Scale (PCPCS). New subcategories of severity for known prognostic parameters have been defined. A correlation analysis was performed between the subcategories of the prognostic parameters and the PCPCS.

RESULTS

A total of 80 patients were included in the analysis. Of these, 64% were male, most of the patients were at the age of 0-5 years. More than 80% of the patients were unattended at a public or private pool when the drowning incident happened. In all, 61% (n = 49) needed cardiopulmonary resuscitation (CPR). Of the resuscitated children, 63% showed good to mildly impaired long-term outcome (PCPCS 1-3). Furthermore, 15% (n = 12) were transferred to rehabilitation. Seven children died during the hospital stay and another four died due to complications in the ten years following the incident. The newly defined subcategories of the parameter submersion time, Glasgow Coma Scale (GCS) at time of admission, body temperature at time of admission, blood pH, blood glucose, and blood lactate level correlated significantly with the PCPCS.

CONCLUSIONS

Supervision of children, especially boys of the age 0-5 years, next to public or private pools is most important for prevention of drowning incidents in Switzerland. Cardiopulmonary resuscitation done by trained staff leads to a better long-term outcome. Medical decision making in severe cases of drowning should consider submersion time, GCS at time of admission, body temperature at time of admission, blood pH, blood glucose, and blood lactate levels, as these parameters correlate with long-term outcome.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment and Prevention of Drowning: 2019 Update

The Wilderness Medical Society convened a panel to review available evidence supporting practices for acute management and treatment of drowning in out-of-hospital and emergency medical care settings. Literature about definitions and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded available evidence supporting practices according to the American College of Chest Physicians criteria and then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking. This is the first update to the original practice guidelines published in 2016.

Sports related to drowning

Aquatic sports are included in the top list of risky practices as the environment per se carries a possibility of death by drowning if not rescued in time. Not only are aquatic sports related to a high risk of death, but also all sports practiced on the water, over the water and on ice. Whatever the reason a person is in the water, drowning carries a higher possibility of death if the individual is unable to cope with the water situation, which may simply be caused by an inability to stay afloat and get out of the water or by an injury or disease that may lead to physical inability or unconsciousness. The competitive nature of sports is a common pathway that leads the sports person to exceed their ability to cope with the environment or simply misjudge their physical capability. Drowning involves some principles and medical interventions that are rarely found in other medical situations as it occurs in a deceptively hostile environment that may not seem dangerous. Therefore, it is essential that health professionals are aware of the complete sequence of action in drowning. This article focuses on the pulmonary injury in sports and recreational activities where drowning plays the major role.

Current Concepts in the Pathophysiology and Management of Near-Drowning

Approximately 6,500 people drown in the United States each year. Nearly 50,000 of the estimated 500,000 annual near-drowning victims seek medical attention. Near-drowning is most common among children, young adults, blacks, males, and in the southern states. Risk factors for near-drowning include ethanol use, drugs, seizures, boating accidents, water sports, inadequate supervision of children, and voluntary hyperventilation. Alcohol use alone is associated with 37 to 47% of these cases. Although anoxia and hypothermia produce the major pathological changes associated with the morbidity of near-drowning, hypothermia may paradoxically exert a protective effect in some cases and is associated with most of the spectacular long term survivals. There is almost no difference in the clinical presentation of freshwater and saltwater near-drowning. Both situations often involve hypothermia, anoxic injury due to cardiac arrest, and the frequent progression to the adult respiratory distress syndrome. Basic principles of management include the immediate institution of cardiopulmonary resuscitation; aggressive rewarming, preferably with cardiopulmonary bypass; continuation of cardiopulmonary resuscitation at least until the patient has been effectively rewarmed; and appropriate supportive care if the patient develops the adult respiratory distress syndrome. Cerebral salvage techniques have not been proved to be beneficial in these patients.

Veterinary Forensic Pathology

Determining the cause of death in animals recovered from bodies of water, swimming pools, or other water-containing vessels is challenging. Animals recovered from water may or may not have drowned. The diagnosis of drowning is usually one of exclusion, requiring information from the crime scene, recovery scene, the medical history or reliable witness accounts. While there are characteristic macroscopic and microscopic lesions of drowning, none are specific and are dependent on the volume and tonicity of the drowning medium. Beyond interpreting the postmortem findings, the court may ask pathologists to comment on the behavioral and welfare implications of drowning. This requires an understanding of the drowning process, which is a complex series of sequential, concurrent, and overlapping cardiorespiratory reflexes, electrolyte and blood gas abnormalities, aspiration, physical exhaustion, and breathlessness eventually culminating in death. This review addresses the mechanisms, lesions, and diagnostic issues associated with drowning in nonaquatic companion animals.

Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Drowning

The Wilderness Medical Society convened a panel to review available evidence supporting practices for the prevention and acute management of drowning in out-of-hospital and emergency medical care settings. Literature about definition and terminology, epidemiology, rescue, resuscitation, acute clinical management, disposition, and drowning prevention was reviewed. The panel graded evidence supporting practices according to the American College of Chest Physicians criteria, then made recommendations based on that evidence. Recommendations were based on the panel's collective clinical experience and judgment when published evidence was lacking.

Diagnosis and management of environmental thoracic emergencies

Physiologic sequelae from increasing ambient pressure in underwater activities, decreasing ambient pressure while at altitude, or the consequences of drowning present a unique set of challenges to emergency physicians. In addition, several environmental toxins cause significant respiratory morbidity, whether they be pulmonary irritants, simple asphyxiants, or systemic toxins. It is important for emergency physicians to understand the pathophysiology of these illnesses as well as to apply this knowledge to the clinical arena either in the prehospital setting or in the emergency department. Current treatment paradigms and controversies within these regimens are discussed.

Forensic Lung Pathology

Sudden and unexpected natural deaths and nonnatural deaths may result from various pulmonary conditions. Additionally, several nonpulmonary conditions of forensic significance may be complicated by the development of respiratory lesions. Certain situations with pulmonary pathology are particularly likely to be critically scrutinized and may form the basis of allegations of medical negligence, other personal injury liability, or wrongful death.1

Drowning--post-mortem imaging findings by computed tomography

The aim of this study was to identify the classic autopsy signs of drowning in post-mortem multislice computed tomography (MSCT). Therefore, the post-mortem pre-autopsy MSCT- findings of ten drowning cases were correlated with autopsy and statistically compared with the post-mortem MSCT of 20 non-drowning cases. Fluid in the airways was present in all drowning cases. Central aspiration in either the trachea or the main bronchi was usually observed. Consecutive bronchospasm caused emphysema aquosum. Sixty percent of drowning cases showed a mosaic pattern of the lung parenchyma due to regions of hypo- and hyperperfused lung areas of aspiration. The resorption of fresh water in the lung resulted in hypodensity of the blood representing haemodilution and possible heart failure. Swallowed water distended the stomach and duodenum; and inflow of water filled the paranasal sinuses (100%). All the typical findings of drowning, except Paltau's spots, were detected using post-mortem MSCT, and a good correlation of MSCT and autopsy was found. The advantage of MSCT was the direct detection of bronchospasm, haemodilution and water in the paranasal sinus, which is rather complicated or impossible at the classical autopsy.

Virtual Autopsy: Two- and Three-dimensional Multidetector CT Findings in Drowning with Autopsy Comparison1

PURPOSE

To retrospectively determine the multidetector computed tomographic (CT) virtual autopsy findings of death by drowning in comparison with autopsy findings.

MATERIALS AND METHODS

The institutional review board of the Armed Forces Institute of Pathology approved this HIPAA-compliant study and did not require informed consent by the next of kin. Total-body multidetector CT was performed, immediately prior to routine autopsy, in 28 consecutive male subjects (mean age, 24.2 years) who died of drowning and a control group of 12 consecutive male subjects (mean age, 50.8 years) who died of sudden death from atherosclerotic coronary artery disease. Images were evaluated for the presence of fluid and sediment in the paranasal sinuses and airways, mastoid air cell fluid, frothy fluid in the airways, pulmonary opacity (ground-glass opacity or airspace consolidation), interlobular septal thickening, and gastric distention and contents (fluid or sediment). Image findings were compared with findings from autopsy reports and photographs.

RESULTS

All drowning subjects had fluid in the paranasal sinuses and mastoid air cells and had ground-glass opacity within the lungs. Twenty-six subjects (93%) had fluid in the subglottic trachea and main bronchi. Fourteen subjects (50%) had high-attenuation sediment in the subglottic airways. Frothy fluid in the airways was present in six subjects (21%). Twenty-five (89%) of the drowning subjects had pulmonary ground-glass opacity with septal lines, which was mild with apical and perihilar distribution in 12 subjects, severe and diffuse in nine, posterior and basilar in three, and limited to the apices in one (not assessed in three of 28 subjects because of decomposition). Control subjects showed mastoid cell fluid (25%), sinus fluid (83%), subglottic airway fluid (92%), and pulmonary ground-glass opacity (100%) but did not have evidence of frothy airway fluid or high-attenuation sediment in the airways.

CONCLUSION

The multidetector CT finding of frothy airway fluid or high-attenuation airway sediment is highly suggestive of drowning; multidetector CT findings of pan sinus fluid, mastoid cell fluid, subglottic tracheal and bronchial fluid, and ground-glass opacity within the lung at multidetector CT are supportive of drowning in the appropriate scenario.

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.

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.

Near drowning: thin-section CT findings in six patients

PURPOSE

The purpose of this study was to assess the thin-section CT findings of near drowning in six patients.

METHOD

Thin-section (1 mm collimation) CT scans of six patients who experienced near drowning were retrospectively analyzed. The CT scans were performed 0-5 days (median 1 day) after near drowning.

RESULTS

Thin-section CT findings included bilateral patchy or diffuse areas of ground-glass attenuation (n = 6) with geographic pattern (n = 3) and fine intralobular reticular opacities ("crazy-paving" appearance) (n = 3), ill-defined centrilobular nodules (n = 4), and air-space consolidation (n = 1). Distribution of ground-glass attenuation was predominantly central (n = 4) or diffuse (n = 2). Interstitial pulmonary emphysema and pneumomediastinum were present in two patients.

CONCLUSION

The thin-section CT findings of near drowning consist of ground-glass opacities with or without associated reticular opacities and centrilobular nodules.

Near drowning

Submersion accidents continue to be a significant cause of morbidity and mortality in children and adults. The key to successful management is prevention of these accidents. Proactive efforts to minimize submersion accidents in the community should be made by medical and legislative groups. Anticipatory guidance by primary care physicians, particularly for families and individuals at increased risk, should be performed. Outcomes of individuals who have become victims of submersion accidents can be optimized by the development of a rapid response system, because successful initial resuscitation efforts clearly improve outcomes. For individuals who have nearly drowned and who have arrived in the emergency department, a systematic and aggressive approach needs to be followed with particular emphasis on cardiorespiratory support to optimize neurologic outcome. Despite many studies aimed at developing predictors of outcomes, there is limited information that can be used in a prospective manner to guide the emergency-room physician in limiting the level of interventions. Thus, all aggressive supportive care and resuscitation should be performed at this stage, except in clearly futile situations. Once patients arrive in the ICU, meticulous care, including monitoring of cardiorespiratory and neurologic status and attention to electrolytes and acid-base status, needs to be continued. Besides providing basic supportive measures, the ICU physician should investigate for other associated trauma and medical conditions that may need to be addressed once the patient is stabilized. Patients who have nearly drowned are likely to have long ICU stays, predisposing them to nosocomial infections. Despite efforts at minimizing barotrauma and volutrauma, many patients who have nearly drowned and who need ventilatory support may develop ARDS. The management of these patients is similar to other patients who have ARDS. However, strategies like permissive hypercapnia that are used commonly in patients who have ARDS may not be suitable in patients who have CNS injury. Despite aggressive care, neurologic injury with long-term sequelae secondary to hypoxic ischemic injury remains a major problem in the management of victims of submersion accidents. It is important for the clinician to keep the pathophysiologic and cellular mechanisms of CNS injury in mind, because future interventions are likely to be based on these pathways. Besides providing care for the patient, it is important for the ICU physician to be sensitive to the needs of the family and to support them through this catastrophe that is likely to place a tremendous financial and emotional burden on most of them.

Near-drowning: epidemiology, pathophysiology, and initial treatment

Drowning is a major cause of accidental deaths, especially in children. The most serious pathophysiologic consequence of near-drowning is hypoxemia, which usually is due to aspiration-induced noncardiogenic edema. Therefore, initial resuscitative efforts need to be directed at establishing adequate oxygenation and ventilation, followed by rewarming and fluid administration. Although completely asymptomatic patients with normal vital signs, oxygenation and chest radiographs require only 4 to 6 hours of observation, many near-drowning victims will require at least 24 hours of observation. Despite these measures, approximately 25% of victims presenting to the Emergency Department will die and another 6% will develop neurological sequelae. Therefore, it is vital that better efforts be made by the community in promoting and instituting water safety programs.

The etiology of pulmonary edema in fresh water near-drowning

Drowning is a significant cause of death in children and young adults. It is thought to result from the inhalation of either fresh or sea water resulting in lung damage and ventilation-perfusion mismatching. The clinical course, chest roentgenographs, serum electrolytes, alveolar-arterial oxygen gradient, and complete blood count of 10 fresh water drowning victims with pulmonary edema were recorded. Six responded dramatically clinically and radiographically within 24 hours, and most did not have significant alterations of their serum electrolyte levels, especially serum chloride. On the basis of the rapid clearing of the pulmonary edema and the lack of evidence of significant fluid aspiration, neurogenic pulmonary edema is postulated to have played a role in the development of the pulmonary edema in these patients.

Arterial gas embolism and hemoconcentration

The charts of all patients with diving-related accidents presenting between 1983 and 1991 were reviewed. Individuals who sustained a neurologic deficit attributable to occlusion of part of the cerebral circulation within 10 minutes of surfacing from a dive and who had a depth time profile less than 80% of the U.S. Navy "no-stop" limits were considered to have had an arterial gas embolism. Their records were reviewed to determine the hematocrit upon first presentation and the final hematocrit prior to discharge or death. Twenty-three patients had hematocrit determinations on more than one occasion. There was a significant decrease from initial to final hematocrit for these patients. No source of significant blood loss was identified in any patient. A significant correlation was found between the magnitude of the fall in hematocrit and the eventual neurologic outcome. We conclude that gas embolism diagnosed using the above criteria produces hemoconcentration, and the degree of hemoconcentration correlates with the severity of the gas embolism. These observations suggest that the pathophysiology of gas embolism is more complex than previously thought and must include diffuse endothelial injury resulting in leak of fluid from the intravascular space.

Potential use of warm butyl alcohol vapor as adjunct agent in the emergency treatment of sea water wet near-drowning

The short-term course of sea water wet near-drowning was studied in anesthetized rabbits breathing spontaneously. Therapeutic trials were incorporated using warm n-butyl alcohol vapor both in inspired air and in inspired oxygen. The purpose was to determine if butyl alcohol vapor might alleviate the hypoxemia of sea water aspiration, possibly by a defoaming action on the fine foam bubbles of alveolar origin in the lung edema even without tracheal foam being present. The findings from 20 rabbits without overt tracheal foam, that had aspirated 2.05 mL/kg of sea water and were placed 10-minutes postaspirationally into four different inhalational treatment groups, showed remarkable differences. Warm butyl alcohol vapor made by humidification of 7.5% solution at 31 degrees C alleviated the hypoxemia. With vapor treatment for 15 minutes, mean arterial oxygen tension (PaO2) was not significantly changed in the water vapor-air group, but increased significantly to 50.5 +/- 4.6, 70.0 +/- 8.9, and 146.7 +/- 40.7 mm Hg in the butanol/water vapor-air, water vapor-oxygen, and butanol/water vapor-oxygen groups, respectively. With treatment for 30 minutes, mean PaO2 increased to 248.3 +/- 38.0 mm Hg with butanol/water vapor-oxygen inhalations, but only to 91.2 +/- 9.8 mm Hg with 100% water vapor-oxygen inhalations. Thus, the inspired vapor of butanol was much more effective in elevation of arterial blood oxygen pressures when combined with oxygen therapy over the values found when 100% water vapor-oxygen treatments were given. Respiratory and cardiac depressant effects from inspired butanol were not evident.(ABSTRACT TRUNCATED AT 250 WORDS)

The hemodynamic and cardiovascular effects of near-drowning in hypotonic, isotonic, or hypertonic solutions

It has been postulated that near-drowning in fresh water may cause hemodilution and hypervolemia due to the hypotonicity of the aspirated water. In contrast, near-drowning in seawater, because of its hypertonicity, may lead to hypovolemic shock. We evaluated the hemodynamic effects of the instillation of 20 mL/kg of solutions of various tonicities (sterile water, 0.225% sodium chloride, 0.45% sodium chloride, normal saline, 2% sodium chloride, and 3% sodium chloride) into the lungs of anesthetized dogs and compared the results with those for control animals who were made anoxic for five minutes. There was no difference in the hemodynamic effects of hypotonic, isotonic, or hypertonic solutions when compared with anoxic controls. There was an immediate fall in cardiac output and increase in pulmonary capillary wedge pressure, central venous pressure, and pulmonary vascular resistance, regardless of the solution, which was statistically the same as the changes in the anoxic controls (P greater than .02). Likewise, the effective dynamic compliance of the lungs decreased precipitously, was indistinguishable between solutions, and was not statistically different from the anoxic controls (P greater than .10). The pulmonary capillary wedge pressure and central venous pressure peaked at ten minutes and then declined gradually over four hours independent of the tonicity of the aspirated fluid. The cardiac output and effective dynamic compliance of the lung dropped rapidly and remained depressed throughout the experiment, and the pulmonary vascular resistance gradually worsened throughout the four hours of study. Similar results occurred with the anoxic controls. The cardiovascular changes that occur with near-drowning and aspiration of water are not dependent on the tonicity of the aspirated fluid but are the direct result of anoxia.

Submersion cases in The Netherlands

Epidemiologic analysis of submersion cases admitted to the intensive and respiratory care unit showed that several interrelated factors preceded submersion. Accidental submersion and traffic accidents represented one third of the causes of submersion. Other relevant causes were illness (29.9%), psychosocial causes (20.1%), alcohol (18.1%), and suicide (9.1%). Age distribution, gender, and mortality rate were different in each group. Young age, submersion during recreational activities, summer months, and normothermia were epidemiologic factors with a favorable prognosis. Our data were compared with national data. WHO-ICD code 994.1 (drowning and nonfatal submersion) is the best entrance for epidemiologic analysis. Five hundred twenty deaths and 690 hospital admissions due to submersion occur in The Netherlands each year. About 460 victims die before they reach a hospital.

Gastric volume and pH in children for emergency surgery

The volume and pH of gastric contents aspirated prior to anaesthesia were measured in 101 children admitted for emergency surgery. The children were aged between 3 months and 15 years. If we define potential patients at risk by means of the volume and pH of the gastric contents, then 50.0% of the children were at risk of aspiration into the lungs. The number of patients at risk was higher in children aged between 6 and 10 years. There was almost the same risk in the groups with abdominal-, urogenital-, and orthopaedic diseases, while the number of patients at risk was less in the group with superficial lesions. The length of fasting time in the child considerably influenced the volume of gastric contents in emergency surgical cases. It is concluded that in children admitted for emergency surgery there is a risk of aspiration of gastric contents into the lungs. The risk is reduced by preanaesthetic fasting. All children admitted for emergency surgery must be carefully evaluated prior to anaesthesia with special reference to gastric aspiration.

Near-drowning

Near-drowning is defined as survival for at least some period of time after suffocation from submersion in a liquid. This article is a comprehensive review of the demography, pathophysiology, treatment, and prevention of near-drowning, an accident that affects approximately 6,000 to 7,000 Americans per year. Forty percent of these victims are children younger than 5 years. Alcohol plays a role in approximately one-half of near-drownings of older victims. Major factors prolonging survival are an age of less than 2 years and immersion in cold water (less than 20 degrees C). Hypoxia and acidosis are the primary physiological derangements, and treatment must be directed toward their correction. The hypothermic patient requires special considerations. The role of aggressive cerebral resuscitation has not been elucidated. Prevention of the circumstances that lead to near-drowning must be stressed as a public service.

Cimetidine in anesthesia: does it minimize the complications of acid aspiration?

The use of cimetidine, an H2-receptor antagonist, to minimize the complications of acid aspiration pneumonia is reviewed. Since Mendelson's early description of acid aspiration in 66 obstetrical patients, attempts have been made to decrease gastric acidity by administering perioperative antacids and/or antihistamine drugs such as atropine and glycopyrrolate. In this review of the literature, strict attention is given to study design and subject selection, methods of collecting gastric samples and reporting both pH and volume measurements, and medications taken on admission, given preoperatively, and as anesthetics. Clinical trials evaluating cimetidine alone and compared with other prophylactic regimens were reviewed, detailing the timing, route, and frequency of drug administration. Cimetidine appears to be effective in minimizing complications of acid aspiration since gastric acidity (pH less than 2.5) is a contributing factor in both the morbidity and mortality of this disease state. In general terms, cimetidine 300 mg po 1.5-2.0 h prior to intubation or 45-60 minutes iv before surgery will decrease gastric acidity below the critical level. This effect may be maintained for up to three hours. Perioperative cimetidine administration, to minimize the complications of acid aspiration, appears to be safe in terms of drug-drug interactions and effects on labor, the fetus, and the newborn child.

Neardrowning and cold water immersion

Though usually preventable, drowning remains a major cause of accidental death in our society. The lethal common denominator in drowning and neardrowning deaths is hypoxia. Aggressive treatment both at the scene and in the hospital is recommended even in those who initially appear lifeless. Hypothermia and the diving reflex probably explain the incredible survival stories in neardrowning. Remember the maxim in cold water immersion: "One is not dead until warm and dead!"

Endotracheal epinephrine in cardiorespiratory collapse

The endotracheal route for the administration of epinephrine has been studied extensively in dogs. There has been little in the medical literature to document the successful use of this technique in humans. The successful use of endotracheally administered epinephrine in two patients with cardiorespiratory collapse is reported. Specific points concerning endotracheal drugs are discussed and a set of guidelines for clinical use is offered.

Saltwater drowning and near-drowning accidents involving children. A five-year total population study in south-east Queensland

A large total population study of childhood saltwater immersion accidents is reported. A total of 49 cases (16 fatalities, 33 survivors) occurred in the five year period from 1971 to 1975 in southeastern Queensland. As a group, more children survive a potentially fatal saltwater immersion (67%) than do those who lose consciousness in freshwater (50%). The serious saltwater accident rate (loss of consciousness or death) in childhood (from 0 to 15 years inclusive, is 3.37/100,000 children per year at risk (fatality rate 1.12). This is low; comparison with freshwater data shows that although the surf presents special hazards to children, it is very much safer than other types of water. Age-specific and site-specific accident and survival rates for saltwater immersions are presented for the first time. Toddlers are disproportionately represented (33% of all children) and their survival rates are lowest. Boating and the use of surfboards, in current practice, are negligible threats to children. The saltwater immersion rate is increasing (although the absolute risk is small) and reasons for this are discussed. Childhood saltwater immersions were unaffected by tidal state. All but one case of immersion occurred during daylight hours, and in younger children immersion occurred often on weekends.

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.