Acta Pædiatrica ISSN 0803–5253

REGULAR ARTICLE

Indoor versus outdoor childhood submersion injury in a denselypopulated cityKam- Lun Ellis Hon (ehon@cuhk.edu.hk), Ting-Fan Leung, Sze-yan Jennette Chan, Kam-Lau Cheung, Pak-Cheung NgDepartment of Paediatrics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong

KeywordChildhood submersion injury

CorrespondenceKam-Lun Ellis Hon, F.A.A.P., Department ofPaediatrics, The Chinese University of Hong Kong,6/F, Clinical Sciences Building, Prince of WalesHospital, Shatin, Hong Kong.Tel: (852)-2632-2859 |Fax: (852)-2636-0020 |Email: ehon@cuhk.edu.hk

Received7 March 2008; revised 9 April 2008;accepted 17 April 2008.

DOI:10.1111/j.1651-2227.2008.00861.x

AbstractAim: To review the outcome of childhood submersion injury (SI).

Methods: We reviewed discharge data of all children with SI who were hospitalized in a university

teaching hospital between January 2002 and January 2008.

Results: There were 15 admissions (8 males and 7 females). Outdoor SI (n = 10) were more

common than indoor SI (n = 5) and 7 cases occurred in public swimming pools with life guard

service. There were significant differences between the two types of SI. Indoor SI more likely occurred

in the Chinese mainland. The victims were generally younger, more likely to have low Glasgow Coma

Scale (GCS), asystole and intubation at the emergency department (ED). They were more likely to

require intensive care, ventilatory support, neurological imaging and had worse neurological sequlae

of death or hypoxic-ischaemic encephalopathy (HIE).

Conclusion: Indoor SI was associated with worse prognosis. All patients with GCS of 3 at ED and required

intensive care support were either dead or incapacitated. Low GCS, pulselessness and intubation at the ED and

seizures are also associated with adverse outcomes. Describing the mode of paediatric SI in a city where SI rarely

occurs serves to heighten public awareness especially of home safety in the prevention of SI.

INTRODUCTIONSubmersion injury (SI), including drowning or near-drowning, has been an important (1,2) yet avoidable causeof mortality in children in many countries. For every drown-ing death, there are almost four hospital admissions and14 emergency department (ED) visits (3). In Miami, SIaccounted for many paediatric accidental deaths (4). Inmany countries, SI was common but became rare afterlaws on obligatory fencing were introduced (2,3). Domesticswimming pools are uncommon in Hong Kong and near-drowning rarely occurred. Many factors, mostly focused onvital signs and physiological parameters, have been studiedin predicting the outcome of SI (5–12). We reviewed all casesof near-drowning managed at the paediatric department ofa university teaching hospital, and compared the mortalityand morbidity between indoor and outdoor SI.

MATERIALS AND METHODSHong Kong, with a population of 7 million people, has adual public and private system for both primary and sec-ondary health care. Although there are 10 government (Hos-pital Authority [HA]) and 10 private hospitals providinggeneral pediatric inpatient service, the HA system providesthe majority of inpatient care. The Prince of Wales Hospital(PWH) is a university teaching hospital situated in the East-ern part of the New Territories in Hong Kong. From 2002,PWH provides tertiary pediatric intensive care unit (ICU)service to this region with a catchment population of over1.1 million. From January 1997, a HA hospital-wide audit

programme called Clinical Management System (CMS) wasin place. This system captures all admissions by their ICD-9diagnostic and procedure codes as entered by dischargingdoctor and/or attending pediatric specialist, discharge sum-mary and the patient demographic information. This systemis able to identify all discharges that remain uncoded as wellas discharge summaries that are not completed. In this ret-rospective study, all children with SI who were hospitalizedin Prince of Wales Hospital (PWH) between January 2002and January 2008 were recruited. The ICD codes used inour CMS search included 994.1 (submersion), E910.2 (swim-ming accident) and accidental drowning (E910.8). Clinicalparameters between indoor and outdoor SI were analyzed byFisher’s exact test or Mann–Whitney U-test as appropriate.Odds ratios and 95% confidence intervals were complied,and p-values <0.05 were considered significant.

RESULTSThere were 15 admissions (8 males: 7 females), and theirclinical features are summarized in Table 1. Outdoor SI (n =10) were more common than indoor SI (n = 5) and sevencases occurred in public swimming pools with life guard ser-vice. The other outdoor SI involved pond (n = 1), well (n =1) and shore (n = 1). There were significant differences be-tween the two types of SI. In indoor SI, the accidents morelikely occurred in the Chinese mainland, and patients trans-ferred to Hong Kong for further care. The victims were gen-erally younger, more likely to have Glasgow Coma Scale(GCS) ≤5, asystole and intubation at the ED. There was atrend that fixed and dilated pupils were documented at ED

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Table 1 Indoor versus outdoor submersion injury in 15 children

Indoor (n = 5) Outdoor (n = 10) p

Age in years (median and IQR) 1.5 (0.6–2.3) 6.5 (3.8–9.0) 0.003Males (%) 2 (40%) 6 (60%) 0.608Swimming pool (%) 0 (0) 7 (70%) 0.026Accident in Mainland China 3 (60%) 0 (0%) 0.022Initial GCS ≤ 5 at ED 4 (80%) 1 (10%) 0.017Fixed and dilated pupils at ED 3 (60%) 1 (10%) 0.077Intubation at ED 4 (80%) 1 (10%) 0.017Asystole at ED 4 (80%) 1 (10%) 0.017

ManagementMechanical ventilation 4 (80%) 1 (10%) 0.017Inotropes 2 (40%) 1 (10%) 0.242Anticonvulsants 3 (60%) 1 (10%) 0.077CT ± MRI imaging 4 (80%) 1 (10%) 0.017ICU support 5 (100%) 3 (30%) 0.026

Outcome 0.013Death 1 (20%) 1 (10%)Neurologic sequelae 3 (60%) 0 (0)Intact neurology 1 (20%) 9 (90%)

ED = emergency department; GCS = Glasgow Coma Scale.∗Analyzed by Fisher’s exact test except age, which was analyzed by Mann–Whitney U-test.

among children with indoor SI (p = 0.077). This group waslikely to require intensive care, ventilatory support and neu-rological imaging, and had poorer neurological sequlae ofdeath or hypoxic-ischaemic encephalopathy (HIE). Therewas a trend that anticonvulsants were used at ED or subse-quently in intensive care unit (ICU) in indoor SI (p = 0.077).All but two cases were previously healthy children withoutpertinent history to the injury. One girl was born prema-turely at 31-week gestation and another girl was a concealedpregnancy born into the toilet bowl at the home of a youngmother.

Eight victims required ICU support (Table S1); two ofthem died and three had severe HIE. These five caseswere briefly described as follows. A 17-month-old girl(case 1) was left unattended for 15 min while her motherwas playing mahjong (a Chinese game) with other relatives.She was found unconscious with her head submerged ina bucket half-filled with unclean water after laundry. Car-diopulmonary resuscitation (CPR) was commenced in theambulance. At the ED of a local hospital, the child remainedin cardiopulmonary arrest. She was resuscitated and trans-ferred to the paediatric ICU of PWH. In ICU, she remainedcritically ill and deeply comatose and succumbed 4 dayslater. A previously healthy 2-year-old boy (case 2) was foundby his grandfather to be lying in a fish pond. CPR was com-menced immediately and he was taken by ambulance to theED of a nearby hospital, where he was resuscitated and thentransferred to the paediatric ICU of PWH. He developedrecalcitrant seizures, generalized cerebral oedema, multior-gan system dysfunction and brain death was subsequentlypronounced.

An 18-year-old unmarried woman (case 3) with concealedpregnancy and no antenatal care gave birth to a 3.06 kg baby

Figure 1 (A) and (B). The top-loading washing machine and the culprit plasticstools on which the victim stood on and plunged into the washing machine.

girl at term in her bathroom toilet bowl. The grandmotherheard the unusual noise and discovered the incident. Whenambulance arrived 30 min later, the baby was found to beapnoeic and pulseless, and CPR was commenced. The new-born was immediately brought to the ED of a nearby hospitalwhere she remained in cardiac arrest. She was resuscitatedand transferred to our neonatal ICU. The infant developedrecalcitrant seizures and HIE. She remained vegetative upto the time of this review (at 22 months).

A 2-year-old boy (case 4) plunged into the hub of a wash-ing machine while left playing unsupervised for 15 min on aplastic stool next to the washing machine (Fig. 1). The par-ents rushed him to a local hospital in Shenzhen in MainlandChina. He was apnoeic and pulseless when assessed at thehospital 15 min following the incident. He was intubated andresuscitated. This child remained comatose on the fourthday, and his parents took him back to Hong Kong for fur-ther management. While arrived at our paediatric ICU, thisboy was found to have multiorgan system dysfunction, cere-bral oedema and seizure. The child remained comatose, andhad spontaneous respiration but no cough or gag reflexes.The parents refused tracheostomy to protect the airway ofthe child and he remained intubated in our paediatric ICUat 3 years of age.

While travelling in Mainland China with his family, a pre-viously healthy 2-year-old boy (case 7) was found submergedin a bucket of water in cardiopulmonary arrest. He was re-suscitated at a local hospital. The child required ventilatorysupport, tube feeding and urinary bladder catheterization.Subsequently, he required tracheostomy for airway protec-tion. He also had repeated convulsions. After 50 days, theparents took this child to Hong Kong against medical advice.He was admitted under the general paediatric team of PWH.Cranial computerized tomography at PWH showed post-hypoxic damage, and his electroencephalogram showedepileptiform discharges. The child could breathe sponta-neously but remained aphasic and spastic. His parents sub-sequently requested him to be transferred to another hospitalfor long-term care.

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Hon et al. Indoor versus outdoor childhood submersion injury

DISCUSSIONSubmersion injuries have been an important yet avoidablecause of mortality and morbidity in children (1,12–14) butthis problem seems to be uncommon in the cosmopolitancity of Hong Kong. Elsewhere in Asia, poor prognosis hasalso been reported. The incidence appears to be quite high inThailand (15,16). In a large Japanese study, poor prognosiswas associated with duration of submersion and necessityof emergency CPR on arrival at the hospital (17). In Singa-pore, drowning is highlighted as an area of concern in child-hood injuries (18). Near-drowning connotes an immersionepisode of sufficient severity to warrant medical attentionthat may lead to morbidity and death. Unlike many cities(1), domestic swimming pools are uncommon in Hong Kongand near-drowning or drowning rarely occurs. Over the past6 years, we had only managed the 15 cases of children withSI. We report the presentation and complications of thesechildren with near-drowning, explore the circumstancesleading to their occurrence, and discuss home safety mea-sures for public education and prevention.

Although outdoor SI was more common, indoor factorsappear to be important in determining its prognosis. Fiveout of the eight ICU cases occurred indoor. The amounts ofwater involved were often small as in cases 1, 3, 4, 6 and7 (Table S1). Severe sequelae may occur despite this smallamount of water and within a short duration of lapse of su-pervision. The first girl was left unattended for a short periodwhen the accident occurred despite the presence of manyadults around. Top-loading washing machine, accompaniedby a convenient stool, was an unusual scenario of submer-sion that resulted in a disastrous consequence (case 4).Supervised environment such as public swimming poolsrarely results in tragic sequelae in our series. The outcomeof one case among the nine SI that happened in swimmingpools and required ICU support was favourable. The out-comes of submersion victims treated with rapid and aggres-sive pre-hospital care show that this setting, but not ED orICU, is the window of opportunity for any medical interven-tion for these submersion victims. The submersion victimsshould be provided advanced cardiac life support, includingintubation as needed, as soon as possible (10). This factormay account for the more favourable outcome of some casesof our outdoor SI, such as those in public swimming poolswhere life-guards were present.

There is no SI in domestic or private swimming pool inthis series. Fencing in domestic swimming pools has been animportant preventive measure overseas, but this is not rele-vant in our local setting (2). It is not sure if fencing aroundponds, lakes or wells might prevent SI. The variety of sitesin which children drown, even within specific age groups,emphasizes the need for a multifaceted approach to SIprevention.

Three cases took place in Mainland China, and their par-ents took them across the border back to Hong Kong forfurther care after these children were initially stabilized atlocal hospitals. The parents of case 4 subsequently refusedall conventional treatments such as tracheostomy. Conse-quently, he remained intubated in our paediatric ICU up tonow.

A bimodal distribution of deaths is observed among ourpatients, with an initial peak in the toddler age group anda second peak in adolescent to young adult males (3,13).Among the toddlers, most incidents occurred in bathtubsand swimming pools. In the latter age group, most inci-dents happened in natural bodies of water. In our case se-ries, the median age for patients with indoor SI was signif-icantly lower than that of outdoor SI (1.5 vs. 6.5 years, p =0.003). The age discrepancy remained significant even whenthe cases that occurred in the Mainland were excluded. Itappears that young children are curious yet unaware of po-tential dangers in their home environment. They may also beunable to retrieve themselves from the small amount of waterwhen they are submerged. In previous studies, males werereported to be more prone to SI. The relatively high rates ofdrowning among black adolescent males may be reduced byimplementing targeted interventions to prevent swimmingpool drowning (1). However, male pre-dominance of SI wasnot observed in our study.

Sadly, SI often occurs in children who are otherwisehealthy. In a previous study, epilepsy was found to be a riskfactor in SI (19). In our series, one child had history of pre-maturity and another had a young unmarried mother withconcealed pregnancy who delivered her baby in a toilet bowl.None of our victims had epilepsy or neurodevelopmentalproblem prior to the accidents.

Many factors have been studied in predicting the outcomeof SI. Most of these studies focused on vital signs and phys-iological parameters, but they did not compare indoor withoutdoor perspectives (5–12). In our series, indoor SI vic-tims were generally younger, more likely to have GCS of 3,asystole and intubation at the ED. They were more likelyto require intensive care, ventilatory support and neurologi-cal imaging, and had more guarded neurological sequelae ofdeath or HIE. All patients with GCS of 3 at ED and subse-quently admitted to our paediatric ICU were either dead orincapacitated. Conversely, the two patients who had GCS >

10 at ED had favourable outcomes. There was a trend (p =0.077) that ‘fixed and dilated pupils’ at ED were more likelyfound in patients with indoor SI. Persistent fixed and dilatedpupils have been reported to be associated with worse prog-nosis (11,12). At the paediatric ICU, there was also a trend(p = 0.077) that presence of seizures was associated withunfavourable outcomes. The small number in our series didnot permit us to work out the factors that predict favourablesurvival. We cannot identify any combination of variablesthat accurately discriminates all intact survivors from thosewith poor outcomes (13). We emphasize the need for initialfull resuscitation in the ED but cast doubt on the utility ofvarious aggressive forms of cerebral monitoring and resusci-tation (11).

In conclusion, low GCS, pulselessness and intubation atthe ED, and mechanical ventilation and ICU support ap-pear to be associated with adverse outcomes. Describingthe mode of paediatric SI in a city where SI rarely occursserves to heighten the public awareness of home and en-vironmental safety issues in preventing SI. Any short ab-sence of supervision on the children is sufficient to result in

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irreversibly grave consequences for SI. Children may diewhen submersed in buckets containing even a small amountof water. Caregivers should be encouraged to empty anybucket, basin or vessel if toddlers are around. Top-loadingwashing machine should not be filled with water when it isnot in operation. In the outdoor, wells should be coveredwith lids and ponds and pools fenced.

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Supplementary materialThe following supplementary material is available for thisarticle:

Table S1 Clinical features and outcomes of the eight patientswho have required ICU support

This material is available as part of the online article from:http://www.blackwell-synergy.com/doi/abs/10.1111/j.1651-2227.2008.00861.x(This link will take you to the article abstract).

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