In at least 10 states, drowning now surpasses all other causes of death among children under 15 years of age.1 A rapidly growing body of research has enhanced our knowledge of the epidemiology and clinical course of these immersion injuries. With this new knowledge, we should be able to implement programs that will prevent many immersion injuries or minimize their consequences. This article summarizes research published generally within the last 5 years and focuses specifically on residential swimming pool immersion injuries among preschool-aged children. More general discussions are available elsewhere.2,3
Children ages 1 to 3 retain the highest rates for non- boat-re Ia ted drowning in the Uaited States.4 For children under the age of 5, drowning now outranks motor vehicle occupant or pedestrian trauma as the single leading cause of injury death.
Earlier reports of the prominence of swimming pool drownings and near drownings at this age have been confirmed by most of the more recent studies. In Los Angeles County, California, children ages 2 to 3 are at higher risk for drowning than any other age group; in that group, 89% of all drownings occur in residential swimming pools.5 A Northern California study found that 58% of all drownings among children ages O to 4 occurred in residential pools.6 In Maricopa County, Arizona (the Phoenix area), 85% of all drownings and near drownings involving children under 5 years of age occurred in swimming pools.7 In the Seattle area, 52% of drownings and near drownings among children ages 1 to 4 occur in swimming pools - a substantial proportion of which are public or semi-public facilities.8
This pattern may not apply to the most northern areas of the country, where there are fewer in-ground swimming pools. In Minnesota, only 10% of drownings among children under 5 years of age involve pools, and this age group is not at high risk,9
The period immediately after a swimming pool is acquired appears to present special risk. Studies from northern California and Brisbane, Australia show that approximately half of all swimming pool drownings and near drownings occur in the first 6 months after the pool is acquired.10·11
The risk to young children associated with residential pool ownership may best be summarized by further results of the northern California study, which surveyed Households with in-ground pools.10 Ninety-one percent of all immersion events at these households occurred in the swimming pool. For household members under 5 years of age, 80% of all reported immersion events, whether at home or elsewhere, occurred in the family pool.
Approximately half of all swimming pool drownings and near drownings occur in the child's own home pool, and the other half occur at the residence of a friend, relative, or neighbor.6'11·12 Prior to the event, at least 80% of children are known to be on the premises where the pool is located and gain access to the pool directly from the house or yard.6'12
The Consumer Product Safety Commission (CPSC) recently documented the activities of children who suffer swimming pool immersion injuries.12 Hie majority of these children were playing, but only 30% were wearing swimsuits; we can infer that their play was not pool oriented. Two thirds of the children were actively supervised by one or both parents, with a lapse of supervision preceding the immersion event lasting a lew minutes at most.
The previously mentioned Seattle area study reinforces the effect of these momentary lapses: "Although supervisors could be identified for 84% of 1 - to 4-year-old children, only 18% were present to witness the event."8 Similarly, 40% of immersion injuries reviewed in the Maricopa County project were attributed at least in part to a lapse in supervision.7
Because potential rescuers are often nearby, immersion times are usually brief - under 5 minutes in the CPSC study.12 However, bystander cardiopulmonary resuscitation (CPR) is not always available. In Sacramento County, for example, 42% of children who died after an immersion in their own home pool were retrieved from the water by a layperson, often a family member, but resuscitation was delayed until emergency medical technicians arrived.6
Solar pool blankets, also known as soft pool covers, have anecdotally been associated with a growing number of swimming pool immersion injuries13 (CPSC, unpublished data, 1991). These devices are designed only to retain heat in the pool and keep debris out. To young children, the covers may appear to provide a firm surface, and individual case reports suggest that children have frequently climbed onto the covers, slipped beneath them, and become obscured from view.
Other common drowning sites for young children include bathtubs and hot tubs, each of which may account for about 10% of cases in children under the age of 5.14'15 In Chicago, 25% of drownings in this age group occur in 5'gallon buckets.16
The likelihood that a child will survive an immersion event, and the likelihood that he or she will survive with normal neurologic status, are largely determined by events occurring within 10 minutes of the onset of immersion.
Consciousness is usually lost after about 2 minutes of anoxia, and irreversible brain damage begins after an additional 2 to 4 minutes. For a favorable outcome to occur, it has long been understood that a brief immersion must be followed fay prompt and effective resuscitation: "Almost all subjects who ultimately survive are making a spontaneous respiratory effort within 5 minutes after extraction from the water, and most do so within 2 minutes."17
Vital Status on Initial Presentation
A child's vital status on initial presentation in the emergency department is a strong predictor of outcome. The outlook for children who still require CPR in the emergency department is truly dismal. For those who are breathing spontaneously and whose neurological status is already improving, the outlook is quite good. The results of many series are remarkably uniform; a few examples follow.
* In one series of 100 patients from central California, 67 were awake on presentation in the emergency department and did well.18 Twenty-two patients were still receiving CPR; all 22 died or survived with severe brain damage. Of 11 unconscious patients who did not require CPR, two died, one survived with severe brain damage, and eight did well.
* Peterson reported a series of 72 survivors of near drowning in San Diego.19 All children who required CPR in the emergency department were discharged with severe anoxic encephalopathy; all these children also had estimated immersion times of more than 5 minutes.
* Allman and colleagues reported a referral series of 66 children admitted to Children's Hospital of Los Angeles after requiring full CPR at an outside hospital.20 Each patient had a Glasgow Coma Score (GCS) of 3 on presentation to the referring hospital. On admission to the Children's Hospital intensive care unit, 37 patients still had a GCS of 3; 26 died and 1 1 sustained severe brain damage.
* Jacobsen and colleagues described 26 children hospitalized after CPR commencing at the immersion site and continuing in the emergency department.21 Spontaneous cardiac activity was obtained after no more than 15 minutes of total CPR. Of 13 children who recovered spontaneous respiration in the emergency department, eight returned to normal and five suffered impairment but were "able to function." Of the 13 children who did not return to spontaneous respiration, nine died and four survived with "incapacitating brain damage."
This pattern - intact or nearly intact survival after prompt resuscitation, death or severe disability if resuscitation is prolonged - has been verified by a recent series from the Seattle area.22 All children who required CPR for greater than 25 minutes (20/20), all those who were in the water for more than 25 minutes (4/4), and all those who did not regain a pulse in the field or emergency department (5/5) died or suffered severe neurologic impairment. Nearly 90% (21/24) of children who had immersions of 10 to 25 minutes or who did not regain spontaneous respirations in the emergency department (18/21) died or were severely impaired.
Unfortunately, trials of specific hospital-based therapies, such as enhanced efforts to control intracranial pressure, have been disappointing.3 Most recently, barbiturate coma has been demonstrated not to be of significant benefit.23
Ice Water Immersion
The special case of ice water immersion deserves mention. Survival with "good neurologic recovery" after at least 66 minutes of immersion was recently reported in a 2-year-old girl.24 Such reports are heartening but uncommon. The effectiveness of prolonged resuscitative efforts including such advanced techniques as extracorporeal rewarming cannot be adequately assessed until treatment failures are reported along with successes. More importantly, survivals after prolonged immersion occur much less frequently than survivals following brief immersion.
On balance, the major issue confronting clinicians currently is not what to do, but when to stop (Table 1). Clinicians should consider terminating resuscitation efforts after no more than 25 minutes total and perhaps earlier, except under extraordinary circumstances. Data from several of the studies mentioned above support the conclusion drawn by Nichter and colleagues that it may be appropriate to discontinue resuscitation efforts in the emergency department if there is no cardiac activity on presentation.25
Factors Associated With a Very High Likelihood of Death or Severe Neurologic Impairment
AN AGENDA FOR PREVENTION
Both the epidemiologie and clinical studies strongly suggest that our efforts to lessen the toll of immersion injury should be directed at preventing unintended immersions from occurring. These same studies provide specific direction for such an effort, which in many locations is already under way.
Enhanced supervision of children by their caretakers is frequently mentioned as the cornerstone of any drowning prevention effort. While no environmental approach can completely replace adequate supervision, it is no less true that a long history of failed attempts to prevent injury by this means mandates that we look elsewhere. Supervising a child is a complex activity that must be performed over long periods of time. It is simply unrealistic to expect sustained improvements in such an activity across an entire population at risk.
Complete pool fencing has emerged as the most promising prevention strategy. This means installing a fence that surrounds the pool itselC separating this hazard from the house and yard where it is located. Earlier studies led to the prediction that the adoption of a universal complete pool fencing requirement might reduce pool drownings and near drownings among young children by 50% to 80%.2
This prediction has been substantiated by more recent work. The CPSC found that in-ground pools without complete fencing were approximately 60% more likely to be involved in immersion events than were fenced pools.26 A recent Australian study estimated that the relative risk for drowning or near drowning in an unfenced pool was 3.76 (95% confidence interval 2.14, 6.62).11 The Maricopa County project estimated that 51% of child swimming pool immersion injuries could have been prevented by adequately maintained complete pool fencing.7 And in New Zealand, where a national pool fencing law was enacted in 1987, it was estimated that 80% of the childhood drownings that occurred in the 5 years prior to enactment could have been prevented by complete pool fencing.27
Recommended Actions for Drowning Prevention
Such pool fencing systems will need to incorporate self-closing, self-latching gates and will need to be maintained properly in order to effectively prevent injuries. In the Arizona study, approximately one third of all cases considered preventable by complete pool fencing were attributed to "an inadequate or unclosed gate or latch."7 A recent report from New South Wales, Australia, where many local governments have passed pool fencing ordinances, found that nearly 35% (10/29) of childhood drownings occurred in improperly fenced pools.28 In all cases, the gate had been propped open, was not properly locked, had been broken or removed, or the fence itself was broken. Three additional drownings occurred despite adequate pool isolation fencing.
The state of Arizona and communities across the United States have recently instituted pool fencing requirements of various degrees of stringency. A model code for such statutes has been developed by the CPSC and will be revised as necessary.
The question has been raised whether to allow partial or complete reliance on the other barriers that have been proposed as alternatives to fences. Pool alarm systems were evaluated several years ago by the CPSC. At that time no satisfactory system existed, but new developments may some day make these a viable option.
More recently, pool safety covers have been proposed. These are rigid covers that must be placed over the pool, either manually or by a motorized drive, whenever the pool is not in use. Such covers suffer an important disadvantage in comparison with fences, in that they must be repeatedly applied and removed to be effective. Again, decades of work have established that such complicated systems are less likely than more "passive" approaches to be effective. Motorized pool covers, which would be easier to operate, cost approximately $6000 in 1992 - substantially more than an adequate pool fence (CPSC, unpublished data, 1991).
Few pool safety covers are in use in the United States, and there are no systematic data on their effectiveness as an injury prevention measure. At present it would be highly irresponsible to advocate, as at least one author has done,29 that such covers would themselves form an adequate barrier.
It is worth asking whether any pool barrier strategy should be made a statutory requirement or whether voluntary installation can be relied on instead. Only 15% of in-ground pools in the United States have a complete pool fence at present.12 This becomes in essence an examination of the attitude-practice gap; will persons favorably disposed to a health-protective behavior engage in that behavior without compulsion? In Sacramento County, California, only 35% of pool owners who support a barrier requirement for all residential pools had a complete fence around their own home pool.30 In New Zealand, where years of public information campaigns had resulted in an 80% vote of support for pool fencing by pool owners, only half that proportion had installed fencing voluntarily.31
Based on the repeated observation that prompt resuscitation is important, mandatory CPR certification for adults and older children in households with pools is worth considering. This provision has not yet been adopted by any jurisdiction. The question again arises as to whether this might be accomplished on a voluntary basis. In the Sacramento study mentioned previously, only half of pool owners who favored such a requirement represented a household with any members holding a current CPR certification.30
What is the role of public information campaigns in drowning prevention efforts? It may be an important initial step to state the objective of such campaigns to be altering beliefs and attitudes toward mandatory behavior change, rather than changing behavior on a voluntary basis. This may be particularly true for childhood drowning prevention, where "the educational process is complicated by the fact that the group of people who constitute the parents of children under 5 years of age changes every few years."32
Many recent injury prevention successes have combined legislative efforts with public information campaigns. Car seats, seat belts, and bicycle helmets are all products that have been brought into widespread use through such combined efforts.33 Drowning now outranks motor vehicle occupant deaths among young children precisely because of the success of such activities. There is every reason to expect that efforts to prevent swimming pool drownings will be similarly successful. Again, pediatricians will play major roles, as counselors to the parents of individual patients and as citizen advocates (Table 2).
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3. Oriowski JR Drowning, near-dnwning and ice-water submersions. Peaiatr Clin NurfA Am. 1987;34:75-92.
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11. Pitt WR, Balanda KR Childhood downing and near-drowning in Brisbane; the contribution of domestic pools. Mf d J Ausi. 1991;1 54:66! -665.
12. Presen! P. CJiiíd Droumíng Study: A Repon on the Epidemiology of Droumings in Residential Puoli tu CMaVen Under Age 5. Washington, DC: Consumer Produci Safety Commission; 1987.
13. Sulkcs SB, van der Jagt EW. Solar pool blankets: another water hazard. Pediatrics. 1990:85:1114-1117.
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19. Peterson B. Morbidity of chiyhood near-drowning, inamena. 1977:59:364-370.
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22. Quan L, Wentz KR, Gore EJ, Copass MK. Outcome and predictors of outcome in pediatrie submersion victims receiving prehospital care in King County, Washington. PAnics. 1990:86:586-593.
23. Nussbaum E. Maggi ]C. Pentobarbital therapy does not improve outcome in nearly dnwied, flaccid- comatose children. Pediatrics. 1988;? 1:630-634.
24. Boite RG, Black PG, Bowers RS, Thome JK, Cornell HM. The use of extracorporea I rcwarming in a child submerged for 66 minutes. JAMA. 1988;260:377-379.
25. Nichter MA, Eve ten PB. Childhood near-drowning: is cardiopulmonary resuscitation always indicated! Crit Ca« Med, 1989:17:993-995.
26. Rodgers OB. Faeton contributing to child drowninga and near-drownings in residential swimming pools. Hum facían. 1989;3hl23-132.
27. Hassall IB. Thirty-six consecutive under 5-year-old domestic swimming pool drownings. Aiut Poedioir J. 1989:25:143-146.
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29. Griffin OC. Don't let anyone die in your pool. Physician and Sportsmediane. 1991:19:157-158, 160.
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31. Langley ]. Fencing of private swimming pools in New Zealand. Community HeolA Stud. 1983:7:285-289.
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33. Wldome MD. Economy, convenience, and safety: can we have it all! Pedtntricj. i990;86:785-787.
Factors Associated With a Very High Likelihood of Death or Severe Neurologic Impairment
Recommended Actions for Drowning Prevention