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PRONE, HOT, AND DEAD "Until your baby can turn himself over you have to decide for him whether he sleeps on his side, his back or his front". The author of this advice to mothers, a noted British paediatrician,l continued "Many babies do seem to prefer sleeping on their stomachs with their heads turned to one side". How important is this decision? In particular, does sleeping position have any bearing on sudden infant death syndrome? This is a natural question because such infants are almost always in their cots when they die. In 1969, Froggatt2 reported that significantly fewer infants who died suddenly and unexpectedly slept in a face up position than did control infants. Many researchers3 have confirmed that a face-down or prone sleeping is more common in SIDS infants than in controls. There have been no reports to the contrary, and only one has questioned this observation.4 Now Fleming and colleagues5 also associate a prone sleeping position with an increased risk of SIDS. How might this position contribute to an infant’s death? Fleming et al investigated the suggestion of Nelson and co-workers6 that excess bedding and a prone position might cause some sudden infant deaths through hyperthermia. Accordingly they evaluated the total thermal resistance of clothing and bedding of 64 infants who died suddenly and unexpectedly and of 134 control infants. There was little correlation between the minimum outside temperature and the amount of bed clothes in either group. Infants aged more than 70 days who died had significantly more bedding than did control infants ofa similar age; this difference was not detected in infants aged less than 70 days. Overnight heating was more common for SIDS infants than for controls. The researchers mention physiological studies7,8 which indicated that in the prone position the exposed surface area of the baby that can contribute to radiant heat loss is less than in the
supine position. Hyperpyrexia has been suggested as a possible mode of sudden and unexpected infant death by several workers,(’ 11 and SIDS parents will often recall that, when found in his cot, the infant was "burning hot" or "lying in a pool of perspiration". The mechanism of death in hyperpyrexia is uncertain and the pathological findings are non-specific. Earlier studies by Fleming et al12 showed that raising the environmental temperature of healthy infants increased respiratory movement, a finding that suggests an effect on the respiratory control system. They propose that an additional factor-for example, a viral infection-is the stimulus for a further increase in metabolic rate, with subsequent loss of respiratory control. This view accords with several other observations-that symptoms of illness, especially of respiratory infection, are present in many infants who die from SIDS;13 that at necropsy nasopharyngitis and tracheitis are commonly present; and that some of the viruses isolated are known to produce apnoeic episodes in infants.14 The numerous risk factors for SIDS have been determined by studies in which significant differences were detected between populations of SIDS infants and their families and appropriate controls. Some factors emerge as stronger discriminants than others, and the Sheffield group15 have devised a predictive at-risk score. Fleming et al show that a prone sleeping position and excess bedding are independent risk factors for SIDS and suggest that "Educating parents about sleeping position for, and correct thermal care of their babies may help reduce the incidence of sudden infant death". Such an educational campaign would
be undertaken with sensitivity, so great is the guilt feeling among affected parents. Additional support for such intervention might be obtained by examining the nursing practices in other areas and other populations. In the UK, the incidence of SIDS in infants of Asian-bom mothers is about half that of infants of UK-born mothers.16 What do we know about their sleeping positions and their bed clothes? Similarly, in New Zealand, is there a difference in these factors between the Maori population (SIDS incidence 6.47/1000 live births), Europeans (3-86), and the Pacific Islanders (1-86)?17 We should not be too surprised if our attempts to prevent or eliminate SIDS by diminishing known risk factors do not work as well as we would wish. Young maternal age was the most powerful discriminant for SIDS in both the Sheffield and the Melbourne18 predictive scoring systems. In Victoria, Australia, the percentage of mothers aged less than 25 years at time of delivery fell steadily from 26% to 20% during 1983-87. Despite this diminution in a strong risk factor, the SIDS incidence remained steady at 2-16/1000 live births.’9 An immense amount of money has been spent on research into SIDS with no effect on the incidence of this condition. Might simple procedures such as changing an infant’s sleeping position and removing a few bed clothes cause a decrease in the number of these tragic deaths? have
to
Jolly H. Book of child care. London: Sphere, 1977: 126. Froggatt P. Epidemiological aspects of the Northern Ireland study. In: Bergman AB, Beckwith JB, Ray GC, eds. Sudden infant death syndrome. Seattle: University of Washington Press, 1970: 32-46. 3. Engelberts AC, de Jonge GA. Choice of sleeping position for infants: possible association with cot death. Arch Dis Child 1990; 65: 462-67. 4. Hassall IB, Vandenberg M. Infant sleep position: a New Zealand survey. NZ Med J 1985; 98: 97-99. 5. Fleming PJ, Gilbert R, Azaz Y, Berry PJ, Rudd PT, Stewart A, Hall E. Interaction between bedding and sleep position in the sudden infant death syndrome: a population based-control study. Br Med J 1990; 1. 2.
301: 85-89. 6. Nelson EAS, Taylor BJ, Weatherall IL. Sleeping position and infant bedding may predispose to hyperthermia and the sudden infant death syndrome. Lancet 1989; i: 199-201. 7. Stothers JK, Warner RM. Thermal balance and sleep state in the newborn. Early Hum Dev 1984; 9: 313-22. 8. Wheldon RE. Energy balance in the newborn baby: use of a mannikin to estimate radiant and connective heat loss. Phys Med Biol 1982; 27: 285-96. 9. Bacon CJ. Overheating in infancy. Arch Dis Child 1983; 58: 673-74. 10. Stanton AN, Scott DJ, Downham MAPS. Is overheating a factor in some unexpected infant deaths? Lancet 1980; i: 1054-57. 11. Denborough MA. Hyperthermia and sudden infant death. Lancet 1989; i: 612. 12. Levine MR, Fleming PJ, Levine MR, McCabe R. The relationship between environmental temperature, metabolic rate and sleep state in infants from birth to two months. Early Hum Dev 1989; 18: 293 (abstr). 13. Stanton AN, Downham MAPS, Oakley JR, Emery JL, Knowelden J. Terminal symptoms in children dying suddenly and unexpectedly at home: preliminary report of the DHSS multicentre study of post neonatal mortality. Br Med J 1978; ii: 1249-51. 14. Williams AL. Sudden infant death syndrome: occasional review. Aust NZ J Obstet Gynaecol 1990; 30: 98-107. 15. Carpenter RG, Emery JL. Identification and follow-up of infants at risk of sudden death in infancy. Nature 1974; 250: 729. 16. Balarajan R, Raleigh VS, Bolting B. Sudden infant death syndrome and post neonatal mortality in immigrants in England and Wales. Br Med J 1989; 298: 716-20. 17. Borman B, Fraser J, deBoer G. A national study of sudden infant death syndrome in New Zealand. NZ Med J 1988; 101: 413-15. 18. Cameron MH, Williams AL. Development and testing of scoring systems for predicting infants with high-risk of sudden infant death syndrome in Melbourne. Aust Paediatr J 1986; (suppl): 37-45. 19. Consultative Council on Obstetric and Paediatric Mortality and Morbidity. Annual reports for the years 1983-87. Jean Gordon Government Printer, Melbourne.
PRONE, HOT, AND DEAD "Until your baby can turn himself over you have to decide for him whether he sleeps on his side, his back or his front". The author of this advice to mothers, a noted British paediatrician,l continued "Many babies do seem to prefer sleeping on their stomachs with their heads turned to one side". How important is this decision? In particular, does sleeping position have any bearing on sudden infant death syndrome? This is a natural question because such infants are almost always in their cots when they die. In 1969, Froggatt2 reported that significantly fewer infants who died suddenly and unexpectedly slept in a face up position than did control infants. Many researchers3 have confirmed that a face-down or prone sleeping is more common in SIDS infants than in controls. There have been no reports to the contrary, and only one has questioned this observation.4 Now Fleming and colleagues5 also associate a prone sleeping position with an increased risk of SIDS. How might this position contribute to an infant’s death? Fleming et al investigated the suggestion of Nelson and co-workers6 that excess bedding and a prone position might cause some sudden infant deaths through hyperthermia. Accordingly they evaluated the total thermal resistance of clothing and bedding of 64 infants who died suddenly and unexpectedly and of 134 control infants. There was little correlation between the minimum outside temperature and the amount of bed clothes in either group. Infants aged more than 70 days who died had significantly more bedding than did control infants ofa similar age; this difference was not detected in infants aged less than 70 days. Overnight heating was more common for SIDS infants than for controls. The researchers mention physiological studies7,8 which indicated that in the prone position the exposed surface area of the baby that can contribute to radiant heat loss is less than in the
supine position. Hyperpyrexia has been suggested as a possible mode of sudden and unexpected infant death by several workers,(’ 11 and SIDS parents will often recall that, when found in his cot, the infant was "burning hot" or "lying in a pool of perspiration". The mechanism of death in hyperpyrexia is uncertain and the pathological findings are non-specific. Earlier studies by Fleming et al12 showed that raising the environmental temperature of healthy infants increased respiratory movement, a finding that suggests an effect on the respiratory control system. They propose that an additional factor-for example, a viral infection-is the stimulus for a further increase in metabolic rate, with subsequent loss of respiratory control. This view accords with several other observations-that symptoms of illness, especially of respiratory infection, are present in many infants who die from SIDS;13 that at necropsy nasopharyngitis and tracheitis are commonly present; and that some of the viruses isolated are known to produce apnoeic episodes in infants.14 The numerous risk factors for SIDS have been determined by studies in which significant differences were detected between populations of SIDS infants and their families and appropriate controls. Some factors emerge as stronger discriminants than others, and the Sheffield group15 have devised a predictive at-risk score. Fleming et al show that a prone sleeping position and excess bedding are independent risk factors for SIDS and suggest that "Educating parents about sleeping position for, and correct thermal care of their babies may help reduce the incidence of sudden infant death". Such an educational campaign would
be undertaken with sensitivity, so great is the guilt feeling among affected parents. Additional support for such intervention might be obtained by examining the nursing practices in other areas and other populations. In the UK, the incidence of SIDS in infants of Asian-bom mothers is about half that of infants of UK-born mothers.16 What do we know about their sleeping positions and their bed clothes? Similarly, in New Zealand, is there a difference in these factors between the Maori population (SIDS incidence 6.47/1000 live births), Europeans (3-86), and the Pacific Islanders (1-86)?17 We should not be too surprised if our attempts to prevent or eliminate SIDS by diminishing known risk factors do not work as well as we would wish. Young maternal age was the most powerful discriminant for SIDS in both the Sheffield and the Melbourne18 predictive scoring systems. In Victoria, Australia, the percentage of mothers aged less than 25 years at time of delivery fell steadily from 26% to 20% during 1983-87. Despite this diminution in a strong risk factor, the SIDS incidence remained steady at 2-16/1000 live births.’9 An immense amount of money has been spent on research into SIDS with no effect on the incidence of this condition. Might simple procedures such as changing an infant’s sleeping position and removing a few bed clothes cause a decrease in the number of these tragic deaths? have
to
Jolly H. Book of child care. London: Sphere, 1977: 126. Froggatt P. Epidemiological aspects of the Northern Ireland study. In: Bergman AB, Beckwith JB, Ray GC, eds. Sudden infant death syndrome. Seattle: University of Washington Press, 1970: 32-46. 3. Engelberts AC, de Jonge GA. Choice of sleeping position for infants: possible association with cot death. Arch Dis Child 1990; 65: 462-67. 4. Hassall IB, Vandenberg M. Infant sleep position: a New Zealand survey. NZ Med J 1985; 98: 97-99. 5. Fleming PJ, Gilbert R, Azaz Y, Berry PJ, Rudd PT, Stewart A, Hall E. Interaction between bedding and sleep position in the sudden infant death syndrome: a population based-control study. Br Med J 1990; 1. 2.
301: 85-89. 6. Nelson EAS, Taylor BJ, Weatherall IL. Sleeping position and infant bedding may predispose to hyperthermia and the sudden infant death syndrome. Lancet 1989; i: 199-201. 7. Stothers JK, Warner RM. Thermal balance and sleep state in the newborn. Early Hum Dev 1984; 9: 313-22. 8. Wheldon RE. Energy balance in the newborn baby: use of a mannikin to estimate radiant and connective heat loss. Phys Med Biol 1982; 27: 285-96. 9. Bacon CJ. Overheating in infancy. Arch Dis Child 1983; 58: 673-74. 10. Stanton AN, Scott DJ, Downham MAPS. Is overheating a factor in some unexpected infant deaths? Lancet 1980; i: 1054-57. 11. Denborough MA. Hyperthermia and sudden infant death. Lancet 1989; i: 612. 12. Levine MR, Fleming PJ, Levine MR, McCabe R. The relationship between environmental temperature, metabolic rate and sleep state in infants from birth to two months. Early Hum Dev 1989; 18: 293 (abstr). 13. Stanton AN, Downham MAPS, Oakley JR, Emery JL, Knowelden J. Terminal symptoms in children dying suddenly and unexpectedly at home: preliminary report of the DHSS multicentre study of post neonatal mortality. Br Med J 1978; ii: 1249-51. 14. Williams AL. Sudden infant death syndrome: occasional review. Aust NZ J Obstet Gynaecol 1990; 30: 98-107. 15. Carpenter RG, Emery JL. Identification and follow-up of infants at risk of sudden death in infancy. Nature 1974; 250: 729. 16. Balarajan R, Raleigh VS, Bolting B. Sudden infant death syndrome and post neonatal mortality in immigrants in England and Wales. Br Med J 1989; 298: 716-20. 17. Borman B, Fraser J, deBoer G. A national study of sudden infant death syndrome in New Zealand. NZ Med J 1988; 101: 413-15. 18. Cameron MH, Williams AL. Development and testing of scoring systems for predicting infants with high-risk of sudden infant death syndrome in Melbourne. Aust Paediatr J 1986; (suppl): 37-45. 19. Consultative Council on Obstetric and Paediatric Mortality and Morbidity. Annual reports for the years 1983-87. Jean Gordon Government Printer, Melbourne.
