Archives of Disease in Childhood 1994; 71: 497-500 497 Potentially dangerous sleeping environments and accidental asphyxia in infancy and early childhood

Roger W Byard, Susan Beal, Anthony J Boume

Abstract situations. For example, two cases in Infants and young children may be which infants asphyxiated in rocking exposed to a variety of dangerous situa- cradles led to the investigation of the tions when left sleeping in cots, chairs, or cradles and to formulation of specific beds. A review of 30 cases of accidental safety recommendations regarding the asphyxia occurring in infants and young angle of tilt. Two infants who died after children who had been left to sleep becoming wedged between the back of a unattended was undertaken from the and a co-sleeping parent in one case necropsy and consultation files of the and in the other, would indicate Adelaide Children's Hospital. Causes of that this also represents a potentially Departments of death included hanging from loose lethal sleeping position. Other dangerous Histopathology and restrainers, clothing, or a curtain cord (12 situations involved infant car seat Ambulatory cases), positional asphyxia/wedging from restraints, seats with loose harnesses, cots Paediatrics, Adelaide Children's Hospital, slipping between a and /cot with movable sides or projecting pieces, Division ofthe sides or wall, or from moving into a thin plastic mattress/ coverings, and Women's and position where the face was covered and beds with spaces between the mattress Children's Hospital the occluded and and Department of upper airway (16 cases), and cot side or wall. Lack ofsupervision at Paediatrics, University suffocation from plastic bed covers (two the time of death was a feature of each ofAdelaide, Adelaide, cases). Cases ofco-sleeping in bed with an case. South Australia, Australia adult and of non-accidental asphyxia (Arch Dis Child 1994; 71: 497-500) R W Byard were not included in this review. As the S Beal pathological findings were on occasion A Bourne J identical to those that are typically Recent research attention has focused on Correspondence to: found in sudden infant death syndrome, the role of the prone sleeping position in the Department ofHistology, adequate death scene examination was aetiology of sudden infant death syndrome Women's and Children's vital in several cases to allow identifica- (SIDS) .1 Also of importance due to the Hospital, 72 King William Road, North Adelaide, 5006, tiontinolehlsoflethal sleepingep gevrnmenvironmentstsadoand to preventable nature of the deaths are situations South Australia, Australia. enable steps to be taken to minimise in which the infant sleeping environment is Accepted 7 September 1994 the risk of future deaths due to similar unsafe. After the recent hanging death of a local infant in a car restraint seat a review was Circumstances ofdeath in 30 cases ofaccidental childhood asphyxia undertaken of the range of situations in which an infant left to sleep may be at risk of sudden Case Monthl Age Time and unexpected death due to accidental No year (months) Sex Circumstances unsupenvised asphyxia. 1 6/66 36 M Cardigan caught on hook outside cot Unknown 2 1/70 18 M Jacket caught on exposed screw on cot Overnight 3 6/70 9 F Chin caught on faulty cot railing 15 Minutes 4 10/74 8 F Slipped in baby car seat Minutes Methods 5 1/76 17 M Jumper caught on cot post 3 Hours 6 2/76 6 M Suspended between foot of adult bed and 3-5 Hours Necropsy records and consultation files at the mattress Adelaide Children's Hospital department of 7 1/78 1 F Sheet ofplastic in pram covered face Unknown 8 5/78 8 F Nightdress caught on cot Unknown histopathology were examined over the past 28 9 1/81 7 M Hanging from cot Unknown years (1966-93). Cases of unexpected deaths 10 10/81 9 M Suspended through bottom of faulty cot Hours 11 12/81 8-5 M Head wedged between mattress and furniture Overnight in infants and young children due to accidental 12 12/82 35 F Hanging from curtain cord 4 Hours asphyxia caused by unsafe sleeping situations 13 5/83 14 M Suspended by chin between adult bed and 1 Hour chest of drawers were reviewed. 14 3/84 15 F Cardigan caught on cot Unknown Deaths were attributed to hanging if there 15 5/84 11 F Cardigan caught on wing nut on cot 45 Minutes 16 10/85 10 M Suspended through bottom of faulty cot Overnight was unequivocal evidence of suspension with 17 6/86 8 M Slipped down in pushchair Overnight ligature marks around the neck, and to 18 7/87 1-5 F Face covered by plastic sheet used to cover Unknown mattress chest/airway compression in cases where the 19 3/88 5 F Head wedged between mattress and bedhead Unknown body was found wedged between the mattress 20 8/89 3 M Face down between and back of couch 2 Hours 21 11/89 4 M Head wedged in cot 1-5 Hours and cot side or wall. In other cases where the 22 11/89 1-5 M Wedged between mother and back of couch 3 Hours mechanism of death was more complicated 23 3/91 11-5 M Head wedged between edge of mattress and Overnight mesh wall of cot involving a combination of hanging, wedging, 24 11/91 14 F Wedged between bed and exposed wall cavity Overnight and airway occlusion, deaths were attributed to 25 1/92 3 F Face down in faulty rocking 3 Hours 26 9/92 2-5 M Face down in rocking cradle - stabilising peg 3 Hours positional asphyxia. out As this review is concentrating on struc- 27 8/93 3 F Slipped down in baby bouncer, hanging from 2 Hours straps turally unsafe sleeping environments, cases 28 11/93 10 F Wedged between adult bed and wall Overnight that were excluded include asphyxial deaths 29 11/93 6 F Head wedged between end of adult bed and Overnight wall due to more generalised unsafe environmental 30 1/94 16 M Slipped down in child restraint seat in car, 20 Minutes conditions such as carbon monoxide poison- hanging from straps ing, deaths due to possible parentally induced 498 Byard, Beal, Bourne

The diagnoses of positional asphyxial deaths y )o v 7 due to compression of the chest and airways by v X > \ wedging of the body were less clear cut than %. V6 IL r hanging, often due to a failure to pass on to the 11 -, ')-,

w examining pathologist pertinent information v X Ir v regarding the position of the body at the v 19 I? I-v,-"gf ..A- death scene. For example, fig 2 illustrates a s i consultation case where a diagnosis of SIDS N-11 X Y - had been initially considered until death scene ., A A information became available. The case involved a 14 month old girl who was put to sleep in an older sibling's bed (case 24). She was found dead wedged between the bed and the unlined wall joists, having crawled under the bar at the head ofthe bed. Given that the bed had to be dismantled to release the body, a diagnosis of death due to accidental asphyxia from wedging was considered more appropriate than the original diagnosis of SIDS. Other wedging deaths occurred in situations where the infant's mattress was quite thick and smaller than the cot, thus permitting the infant to slip into the Figure 1 Sketch of a 3 month old gin who wasfound crevice between the mattress and cot sides. dead hangingfrom the loose harness ( facial petechiae were present. One case of positional asphyxia occurred due to the pliability of the woven mesh side of a cot that allowed an infant's head and upper airway obstruction, deaths due to inhaled body to slip into the space at the edge of the foreign bodies, and deaths o:f infants co-sleep- mattress (case 23). The elastic recoil of the ing in bed with adults. mesh then forced the infant's head and face into the side of the mattress resulting in suffocation. Infants sleeping in older sibling's Results or parents' beds are also in danger of slipping Thirty cases were identified, the details of between the mattress side and the wall when a which are summarised in the table. Ages gap of sufficient size exists. ranged from 1 month to 3 years with an Two infants died when they slipped off average age of approximatelly 10 months. The pillows into the crevice at the back of a couch, male to female ratio was 16:14. Causes of formed in one case by an adjacent sleeping death involved hanging (fiig 1) from loose parent (case 22), and in the other by outward restrainers, clothing, or a curtain cord (12 displacement of the bottom cushions of cases), positional asphyxiaJwedging (fig 2) the couch (case 20). Several cases of fatal from slipping between the mattress and cot positional asphyxia occurred in faulty cots sides or wall, or between a slleeping parent/pil- where infants slipped between the side and the low and the back of a couchi, or from moving base of a cot, or through the bottom of the cot, into a position where the face was covered or became caught in faulty railings (cases 3, 10, and the upper airway occluded (16 cases), and and 16). suffocation from plastic 1bed covers (two Although the Adelaide Children's Hospital cases). (The pathological ifeatures of 12 of is the major paediatric treatment centre in these cases have been previously reported.2) South Australia, serving a population which has ranged from 1 094 984 in 1986 to 1 459 000 in 1992,3 the numbers of locally referred paediatric forensic cases and interstate consultation cases contributing to the total number of departmental necropsy cases has varied over the 28 years of the study. While most local paediatric forensic cases would have had a necropsy performed in the department, .Ai&-4 . the variability in referral pattern precludes the drawing of too many formal epidemiological O.e conclusions from the data. The material tA represents one institution's experience of fatal paediatric sleeping environments, accounting L2 7 for less than 1 % of the total number of 4 necropsies overall.

Discussion 4' Hanging deaths due to ligature suspension in Figure 2 The body of a 14 month old girl was extricated infants are among the most readily diagnosable from the space between the head of the bed and the adjacent death due to the unlined wall. The arrow indicates the gap through which causes of accidental asphyxial she crawled. .;W position of the body at the death scene and to Potentially dangerous sleeping environments and accidental asphyxia in infancy and early childhood 499

the pathological findings elicited at necropsy. Unfortunately, necropsy findings in cases of In the Adelaide Children's Hospital series a upper airway occlusion are also relatively variety of risk factors were identified. For non-specific. Thus, cases in which an infant example, several infants had been sleeping in has been found with the plastic covering of a seats with loose restraining harnesses such mattress or pillow around the face are usually as car seats, pushchairs (strollers), or baby indistinguishable pathologically from SIDS. bouncers (bouncinettes). These infants had Attention has also been drawn to the dangers slipped out of the restraints which had then to infants sleeping on as an infant caught around their necks resulting in hanging. may suffocate in the deep hollow caused by the This situation is illustrated in fig 1 by a 3 month weight of the body and the head on the bed.7 old infant who was found hanging in her baby Infant deaths on waterbeds were rare in the bouncer, having partially slipped out of the har- Adelaide Children's Hospital necropsy files ness after being left unattended. Older children and when such deaths did occur, the beds were may also be at risk such as the 16 month old boy not thought to be causally related as they were who was left alone for some time in a car seat either rightly filled and not indentable, or else restrainer (case 30). Older children who were non-asphyxial causes of death were identified. able to stand in their cots had also asphyxiated Recent evidence has also demonstrated that from hanging either as a result of putting their rebreathing of carbon dioxide may play a part heads through a nearby curtain cord in one case in the deaths of infants sleeping on polystyrene or from catching clothing on projections on bags8 and possibly on natural fibre .9 the sides of their cots. Hazardous sleeping The contribution of rebreathing to the lethal environments were found to be particularly event in SIDS and some cases of positional dangerous for infants and younger children, asphyxia awaits further clarification. with no children older than 3 years being The prevention of accidental deaths such as detected in this series. Lack ofsupervision at the those described in this series is obviously a time of fatal asphyxiation was a feature of all of priority. Continued parental and community the cases where a history was available. education on potential dangers for sleeping The space between the mattress of an adult infants is needed and pamphlets detailing or older sibling bed and the wall represents a particular problems could be made available potentially dangerous environment for infants at child care centres and outpatient facilities. and positional asphyxia associated with Specific dangers to be mentioned would wedging in such situations had been reported include poorly fitting mattresses with gaps in other series.4 Airway occlusion may also along the sides, plastic bags including filmy occur in cots with slats that were widely plastic mattresses and pillow covers, the use separated or broken allowing trapping of the of adult or older sibling beds for infants head.5 Although legislation with well defined (including water beds), sleeping on , safety specifications now covers the manu- secondhand and broken cots, cots with elastic facture of most cot types in Australia, it is mesh sides, rocking cradles with excessive almost impossible to apply these rules to angles of tilt and faulty locking devices, cots secondhand or broken cots. Unfortunately with projecting hooks or catches, any bed legislation also does not yet cover rocking within reach of curtain cords, seats with cradles in which the cot is pivoted from an loose harnesses or restraining belts, and overhead frame, thus allowing tilting to occur. unsupervised car restraint seats, pushchairs, Deaths of two young infants who were left and baby bouncers. While signs warning of untended in rocking cradles with marked the dangers of lack of supervision should angles of tilt and faulty locking devices be displayed prominently on seats with prompted a recent investigation by one of the restraints, these may still be ignored by authors (SB). The infants had asphyxiated parents with dire consequences, as occurred when they were unable to extricate their heads in case 30 where a label warning against from the angle between the side and the floor leaving a child unsupervised in the harness of the cot.6 A recommendation of a maximum was clearly visible. Legislation should also be angle of tilt of 50 has been made after an enacted to ensure that cots and infant/child examination of infant responses to different seats meet minimum safety standards before angles of tilt under a variety of experimental sale. conditions. As necropsy markers of asphyxia in infants Necropsy findings in cases of asphyxia due may be absent or very subtle there exists a to wedging may be quite non-specific and may potential for the misdiagnosis of SIDS in be identical to those found in cases of SIDS.4 cases of accidental asphyxia. Although the Thus without a careful death scene examina- usefulness and practicality of death scene tion and report to the pathologist, there investigation has been recently questioned,'0 11 is the possibility that such cases may be we consider that careful death scene investiga- misdiagnosed. Occasionally, however, unusual tion in all cases of sudden infant death is vital patterns of lividity or bruising around the face so that the causes of accidental death can or back and side of the head may provide be accurately determined and potentially morphological evidence of wedging of the dangerous sleeping environments identified. body. For example, linear facial marking with Publicising hazardous sleeping arrangements unilateral congestion was demonstrated in a may make parents and infant minders aware of 10 month old girl who slipped between the potentially dangerous situations, and reporting mattress and the wall while sleeping in an adult of unsafe cots or beds may result in their bed (case 28). modification or withdrawal from sale. 500 Byard, Beal, Bourne

We would like to thank Mr Wayne Chivell, coroner, Adelaide, Unexpected infant death in association with suspended for permission to use fig 1 and Mr Frank Potts, coroner, rocking cradles. Am Jf Forensic Med Pathol (in press). Hobart, for permission to use fig 2. 7 Gilbert-Barness E, Hegstrand L, Chandra S, et al. Hazards of mattresses, beds and in deaths of infants. Am 1 Stanley FJ, Byard RW. The association between prone Forensic Med Pathol 1991; 12: 27-32. sleeping position and SIDS: an editorial overview. 8 Kemp JS, Thach BT. Sudden death in infant sleeping on J7 Paediatr Child Health 199 1; 27: 325-8. polystyrene-filled cushions. N Engl Jf Med 1991; 324: 2 Moore L, Byard RW. Pathological findings in hanging and 1858-64. wedging deaths in infants and young children. Am Jf 9 Ponsonby AL, Dwyer T, Gibbons LE, Cochrane JA, Wang Forensic Med Pathol 1993; 14: 296-302. Y-G. Factors potentiating the risk of sudden infant death 3 Gardner PM. Population. South Australian year book. No 28: syndrome associated with the prone position. N Engl 1994. South Australia: Australian Bureau of Statistics, Med 1993; 329: 377-82. Government Printer, 1994: 49-55. 10 Sankaran K. Sudden infant death syndrome: an interactive 4 Cohle SD. Accidental death. In: Byard RW, Cohle SD, hypothesis and a personal perspective for prevention. eds. Sudden death in infancy, childhood and adolescence. Annals of the Royal College of Physicians and Surgeons of Cambridge: Cambridge University Press, 1994: 6-46. Canada 1993; 26: 277-80. 5 Variend S, Usher A. Broken cots and infant fatality. Med Sci 11 Guntheroth WG, Spiers PS, Naeye RL. Redefinition of the Law 1984; 24: 111-2. sudden infant death syndrome: the disadvantages. Pediatr 6 Moore L, Bourne AJ, Beal S, Collett M, Byard RW. Pathol 1994; 14: 127-32.