Prone sleeping position and SIDS: evidence from recent case-control and cohort studies in Tasmania

Back to the Breast: An Historical Overview of the Perceived Connections Between Sudden Infant Death Syndrome and Breastfeeding

In the late 19th century, physicians in the United States and Europe grew concerned about an increasingly visible subset of infant mortality: sudden infant death. Over the next 100 years, physicians worked variably to combat the problem, modifying and refining their conceptions of sudden infant mortality many times over the process. Physicians' overlapping revisions of sudden infant mortality ultimately helped to produce the categorization of Sudden Infant Death Syndrome (SIDS), and their ensuing, fluctuating efforts to resolve this problem shed light on social and medical perceptions of the roles that biology, the environment, and infant care practices played in sudden infant death. SIDS's official medical classification was a watershed; not only did the formal medical label establish its "authenticity" as a medical phenomenon, but the label also asserted the inexplicability of (at least some) sudden infant death episodes while simultaneously conveying that affected parents were deserving victims of a tragic loss. In the modern history of sudden infant death in the United States, breastfeeding, in particular, was understood variably as a possible cause for unnecessary infant mortality in the decades surrounding 1900; inconsequential to the occurrence of SIDS in the mid 1900s; and finally as an important and healthful way to reduce the risk for SIDS beginning in the late 1900s.

Who to target in sudden unexpected death in epilepsy prevention and how? Risk factors, biomarkers, and intervention study designs

The risk of dying suddenly and unexpectedly is increased 24- to 28-fold among young people with epilepsy compared to the general population, but the incidence of sudden unexpected death in epilepsy (SUDEP) varies markedly depending on the epilepsy population. This article first reviews risk factors and biomarkers for SUDEP with the overall aim of enabling identification of epilepsy populations with different risk levels as a background for a discussion of possible intervention strategies. The by far most important clinical risk factor is frequency of generalized tonic-clonic seizures (GTCS), but nocturnal seizures, early age at onset, and long duration of epilepsy have been identified as additional risk factors. Lack of antiepileptic drug (AED) treatment or, in the context of clinical trials, adjunctive placebo versus active treatment is associated with increased risks. Despite considerable research, reliable electrophysiologic (electrocardiography [ECG] or electroencephalography [EEG]) biomarkers of SUDEP risk remain to be established. This is an important limitation for prevention strategies and intervention studies. There is a lack of biomarkers for SUDEP, and until validated biomarkers are found, the endpoint of interventions to prevent SUDEP must be SUDEP itself. These interventions, be they pharmacologic, seizure-detection devices, or nocturnal supervision, require large numbers. Possible methods for assessing prevention measures include public health community interventions, self-management, and more traditional (and much more expensive) randomized clinical trials.

Infant Mortality and SIDS Perceptions Among Key Healthcare Professional Informants in Sedgwick County, KS

INTRODUCTION

Sedgwick County, KS, has one of the highest infant mortality rates (IMR) in the USA, of which sudden infant death syndrome (SIDS) is a large component. The purpose of this study was to assess local key informants' awareness of the high IMR overall, their knowledge and beliefs about SIDS risk factors specifically, and their recommendations for ways to increase physician and community awareness of SIDS within Sedgwick County, KS.

METHODS

Structured interviews were conducted with key informants from Sedgwick County, KS.

RESULTS

Four themes emerged from key informant interviews: low level of awareness of infant mortality and SIDS, target population most at risk for SIDS/infant mortality, and barriers to and importance of SIDS education. Key informants were in consensus that there was a lack of general community awareness surrounding the high IMR in Sedgwick County. Strategies were identified to address this issue, including consistent SIDS education of medical providers and parents, social support to moms, use of social media, and involving the faith community in educating target populations about risk factors.

CONCLUSIONS

Health and public health key informants provided an overall view of their perception of the SIDS problem in Sedgwick County, KS. Based on collected interviews, the consensus was there are significant problems within Sedgwick County around the issue of SIDS awareness (severity of the problem), SIDS risk, and barriers to increasing SIDS education among professional and community members. African-Americans were identified as the population with the highest infant mortality and SIDS rates in Sedgwick County by health and public health key informant participants. A concerted, educational approach was recommended as the best way forward to reduce SIDS risk within this community.

Characterization of obstructive sleep apnea before and after tongue-lip adhesion in children with micrognathia

OBJECTIVES

To characterize airway obstruction before and after tongue-lip adhesion in children with micrognathia using polysomnography.

DESIGN

Retrospective pilot case series.

PARTICIPANTS AND METHODS

Evaluation of all children with micrognathia who underwent tongue-lip adhesion and polysomnography before and after surgery from 2002 to 2007 (N  =  8).

RESULTS

Eight children met inclusion criteria; six were girls. The mean interval between polysomnography and tongue-lip adhesion was 6 days (range, 2 to 13 days) preoperatively and 17 days (range, 5 to 32 days) postoperatively. Severe obstructive sleep apnea was identified in seven of eight (88%) children, with a mean preoperative obstructive apnea hypopnea index of 52.6 events per hour (range, 7.1 to 85.7 events per hour). None had significant central sleep apneas (>5 per hour). Tongue-lip adhesion resulted in a mean decrease of 34.5 events per hour (range, -65.8 to 71.6 events per hour). After tongue-lip adhesion, seven of eight (87.5%) patients had an improved obstructive apnea hypopnea index, with resolution of obstructive sleep apnea in one child and improvement to mild (two) and moderate (two) obstructive sleep apnea in four others. Only one child had an obstructive apnea hypopnea index that increased after tongue-lip adhesion. Peak end-tidal pCO(2) measurements were elevated in all eight children before surgery at a mean of 60 mm Hg (range, 52 to 76 mm Hg) that improved to 51 mm Hg (range, 45 to 59 mm Hg), with normal peak levels in four children. Oxygen saturation nadir improved from 73% (range, 58% to 81%) to 82% (range, 65% to 94%).

CONCLUSIONS

Tongue-lip adhesion may be performed in micrognathic infants to alleviate airway obstruction. Polysomnographic evaluation in this pilot study before and after surgery suggests that tongue-lip adhesion usually improves obstructive sleep apnea, but only 38% had complete resolution. Future studies of tongue-lip adhesion efficacy should include polysomnographic evaluation.

Influence of prior advice and beliefs of mothers on infant sleep position

OBJECTIVES

To determine the relationship between the advice mothers receive about infant sleep position and the actual position they place their infants in to sleep and to understand modifiers of that relationship, especially beliefs about infant comfort and safety.

DESIGN

Cross-sectional, face-to-face interviews.

SETTING

Women, Infants, and Children centers in the United States from 2006 to 2008.

PARTICIPANTS

A total of 2299 predominantly African American mothers of infants younger than 8 months.

MAIN EXPOSURE

Advice received and beliefs about infant sleep position.

OUTCOME MEASURE

Usually supine infant sleep position.

RESULTS

Advice for exclusively supine infant sleep position from family (OR, 1.6; 95% CI, 1.17-2.17), doctors (OR, 2.28; 95% CI, 1.77-2.93), nurses (OR, 1.46; 95% CI, 1.15-1.84), or the media (OR, 1.54; 95% CI, 1.22-1.95) was associated with usually placing an infant supine to sleep. Additional sources of advice for exclusively supine position significantly increase the odds that an infant will be placed supine. Mothers who believe an infant is comfortable supine are more likely to place their infants on their backs to sleep (OR, 4.05; 95% CI, 2.51-6.53). Mothers who believe an infant will choke on its back are less likely to place their infants supine (OR, 0.36; 95% CI, 0.24-0.54).

CONCLUSION

Among predominantly African American mothers, increasing advice for exclusively supine sleep and addressing concerns about infant comfort and choking remain critical to getting more infants on their back to sleep.

Sudden infant death syndrome: changing epidemiologic patterns in California 1989-2004

OBJECTIVE

To evaluate the changes of sudden infant death syndrome (SIDS) epidemiology in California.

STUDY DESIGN

We used 1989 to 2004 California statewide death registry data. SIDS cases were selected by "age of decedent" <1 year and "cause of death" listed as SIDS.

RESULTS

We identified 6303 cases (61% males) of SIDS. SIDS incidence rate decreased by 77%, from 1.38 per 1000 births in 1989 to 0.31 per 1000 births in 2004. No further decrease in SIDS incidence was noted from 2002 to 2004. The incidence rate was highest among blacks (2.02 per 1000 births) and lowest in Asian/Pacific Islanders (0.46 per 1000 births). The overall median age at death was 82 days, with no significant change over time. However, the peak age at death shifted from 2 months of age in 1989 to 2001 to 3 months of age in 2002 to 2004. Seasonal variation in the incidence of SIDS was attenuated. The difference in incidence rates between weekdays and weekends increased over the study period.

CONCLUSIONS

The incidence rate of SIDS declined in California from 1989 to 2001, with no further decline after 2002. Several epidemiologic changes were noted: The peak age of SIDS death shifted from 2 months to 3 months of age; seasonal variation diminished; and weekday to weekend difference became more pronounced.

Factors associated with bed sharing and sleep position in Thai neonates

BACKGROUND

Sleep in a supine position and in a bed separate from but proximate to adults is recommended, in several Western countries, to prevent Sudden Infant Death Syndrome (SIDS). Cultural differences and a lower rate of SIDS in Asian populations may affect concern with this problem and thus infant sleeping arrangements. Objective To study bed sharing and sleep position in Thai neonates and the relationship to infant and maternal characteristics.

METHODS

A cross-sectional survey based on interviews with parents of infants aged 21 days old, was conducted under the Prospective Cohort Study of Thai Children.

RESULTS

Of the total sample, 2236/3692 (60.6%) infants shared a bed with their parents. Sixty per cent of the parents placed their infants to sleep in a supine position, 32.2% on their side and 4.9% in a prone position. Bed sharing was associated with older maternal age, higher education, Muslim mother, and with work status of professional career or unemployed. Placing the infants to sleep in a prone position was associated with infant birth weight of greater than 2500 g, older maternal age, higher education, Buddhist mother, mother with professional career and middle-class household economic status.

CONCLUSIONS

Infant bed sharing is a common practice in the Thai culture, as in other Asian countries. The prone sleep position is less common than in Western populations. The main factor associated with both bed sharing and putting infants to sleep in the prone position was a higher maternal socioeconomic status (SES), in contrast to previous studies in some Western countries in which both practices were associated with low maternal SES. Cultural differences may play an important role in these different findings.

Impact of asthma on self-reported health status and quality of life: a population based study of Australians aged 18-64

BACKGROUND

The impact of asthma has traditionally been measured in terms of the prevalence of the disease, mortality rates, and levels of healthcare utilisation, particularly hospital admissions. However, the impact of asthma extends beyond these outcomes to include effects on lifestyle, well being, and perceived health status.

METHODS

Information on self-reported current asthma status, arthritis and diabetes as well as measures of life satisfaction, self-assessed health status, psychological distress, and interference with usual activities was obtained for 14 641 respondents aged 18-64 years in the 2001 National Health Survey of the general population in all states and territories in Australia. Log linear models were fitted separately for each of the dichotomised quality of life measures as dependent variables. The estimates of the adjusted rate ratio obtained from each model were used to compute the population attributable fraction (PAF) of self-reported asthma, arthritis, and diabetes for each of the health status and quality of life measures.

RESULTS

The presence of asthma accounted for 3.18% (95% CI 2.13 to 4.23) of people reporting poor life satisfaction, 8.12% (95% CI 6.57 to 9.67) of people reporting poor health status, 5.90% (95% CI 4.19 to 7.61) of people reporting high psychological distress, and 3.58% (95% CI 2.16 to 5.01) of people reporting any reduced activity days. The proportions of people with these adverse health states attributable to asthma were higher than the proportions attributable to diabetes but lower than the proportions attributable to arthritis.

CONCLUSION

Asthma is an important contributor to the burden of ill health and impaired quality of life in the community. A strategic approach is needed to develop and implement strategies to address the impact of asthma on quality of life.

Infant sleeping position and the sudden infant death syndrome: systematic review of observational studies and historical review of recommendations from 1940 to 2002

BACKGROUND

Before the early 1990s, parents were advised to place infants to sleep on their front contrary to evidence from clinical research.

METHODS

We systematically reviewed associations between infant sleeping positions and sudden infant death syndrome (SIDS), explored sources of heterogeneity, and compared findings with published recommendations.

RESULTS

By 1970, there was a statistically significantly increased risk of SIDS for front sleeping compared with back (pooled odds ratio (OR) 2.93; 95% confidence interval (CI) 1.15, 7.47), and by 1986, for front compared with other positions (five studies, pooled OR 3.00; 1.69-5.31). The OR for front vs the back position was reduced as the prevalence of the front position in controls increased. The pooled OR for studies conducted before advice changed to avoid front sleeping was 2.95 (95% CI 1.69-5.15), and after was 6.91 (4.63-10.32). Sleeping on the front was recommended in books between 1943 and 1988 based on extrapolation from untested theory.

CONCLUSIONS

Advice to put infants to sleep on the front for nearly a half century was contrary to evidence available from 1970 that this was likely to be harmful. Systematic review of preventable risk factors for SIDS from 1970 would have led to earlier recognition of the risks of sleeping on the front and might have prevented over 10 000 infant deaths in the UK and at least 50 000 in Europe, the USA, and Australasia. Attenuation of the observed harm with increased adoption of the front position probably reflects a "healthy adopter" phenomenon in that families at low risk of SIDS were more likely to adhere to prevailing health advice. This phenomenon is likely to be a general problem in the use of observational studies for assessing the safety of health promotion.

Effect of religious observance on infants' sleep position in the Jewish population

OBJECTIVES

To describe the effect of the level of religiousness on infants' sleep position in the Jewish population.

METHODS

A longitudinal telephone survey of randomly selected 608 2-month-old Jewish infants repeated at 4 and 6 months. Results were analyzed versus the four levels of Jewish religion observance.

RESULTS

A significant correlation was found between the level of religious practice and sleep position (P < or = 0.002). 56.8% (50/88) of ultra-orthodox parents put their babies to sleep in the non-prone position, compared with 79% (411/520) in the other three groups (P < 0.001). Non-prone sleeping decreased when infants grew. Higher parity correlated with the level of religiousness and with prone sleeping in religious families (OR = 1.15, 95% CI 1.00-1.33, P < 0.001).

CONCLUSIONS

Jews and especially the ultra-orthodox families comply significantly less with recommendations to avoid prone sleeping. Specific measures may be required in this population that rely more on personal experience and belief than on health care provider advice.

Sleep and breathing disturbances in infancy and early childhood

The nature of sleep-related breathing problems varies with age. Ventilatory function may be compromised at the level of the brainstem, the autonomic nerves, or the upper airway musculature. These disorders are state-dependent, being impacted by both rapid eye movement and non-rapid eye movement sleep, and also by the degree of maturation of the nervous system. Many are treatable. An understanding of the molecular basis of these disorders is just now becoming apparent.

Quality of diet, body position, and time after feeding influence behavioral states in low birth weight infants

The effects of variations in carbohydrate and fat intake and body position on behavioral activity states were evaluated in 64 healthy, growing low birth weight infants (birth weight, 750-1600 g). The infants, enrolled in a prospective, randomized, double-blind, controlled study of effects of quality of dietary energy, were fed one of the five formulas. These formulas contained fixed intakes of protein (4 g/kg per day) but different intakes of carbohydrate (9.1 to 20.4 g/kg per day) and fat (4.3 to 9.5 g/kg per day). Six-hour daytime sleep studies were performed at 2-wk intervals from time of full enteral intake until discharge (mean postconceptional age at first study, 33.2 +/- 1.8 wk). Infants were randomly assigned to the prone or supine position for the first 3-h postprandial period; the position was reversed during the second 3 h. Behavioral activity state, i.e. quiet sleep (QS), active sleep, indeterminate sleep, awake, or crying was coded each minute throughout the postprandial period. The overall incidence of QS was almost double in the prone position versus the supine (p < 0.0001). In contrast, the probability of being in either of the two wakeful states (awake and crying) was increased when infants were placed in supine position (p < 0.0001). Increased likelihood of being in QS while prone was found only during the 30 min after and before feeding in a 150-min prandial cycle. In contrast, increased amounts of awake and crying in supine position were observed throughout the feeding interval. As carbohydrate intake increased, time spent in QS in supine position increased (from 8.6% to 12.5%, p < 0.02), and a trend in the same direction was noted for the prone position (p = 0.06). However, during postprandial minutes 10-100, when QS is likely to be entrained by the nutrient intake, enhancement of QS was found in the prone position only (p < 0.02). Carbohydrate intake influences the total time spent and the distribution of behavioral activity states within the postprandial period in low birth weight infants. The effect of nutrient intake on sleep profile is dependent on body position and time after feed. Mechanistic hypotheses relating sudden infant death syndrome to sleeping position may need to take these observations into account.

Infanticide: is its incidence among postneonatal infant deaths increasing?: an 18-year population-based analysis in California

The decline in the incidence of sudden infant death syndrome (SIDS) and recent recommendations regarding the differentiation of SIDS and child abuse has generated speculation that some cases of infanticide were misdiagnosed as SIDS. The aims of this study were to determine the change in incidences and proportions of postneonatal deaths from all causes, SIDS, and infanticide in California over an 18-year interval encompassing years before and after the Back to Sleep campaign. Selected postneonatal mortality data from 1981 through 1998 obtained from the California Department of Health Services were analyzed and graphically displayed. The total postneonatal mortality and incidence of SIDS deaths per 100,000 live births decreased 45% and 66%, respectively, during the study interval; the incidence of infanticide remained low. The ratio of infanticide to SIDS increased from 4.3 per 100 in 1981 to 10.2 per 100 in 1998. Infanticide deaths, as a percentage of the total number of postneonatal deaths, increased slightly from the first to the second half of the study interval but never rose above 3.2%. It is concluded that this increased percentage is due to a decrease in SIDS deaths and not to an actual increase in infanticide deaths.

Intrathoracic petechiae in sudden infant death syndrome: relationship to face position when found

Previous studies have not addressed the relationship of intrathoracic petechiae (IP) to the position of the face when a caretaker finds a victim of sudden infant death syndrome (SIDS). The aims of this retrospective study were to determine (1) the rate of the facedown position in SIDS (not to be confused with the prone body position), (2) if the facedown position occurred more frequently among SIDS victims with intrathoracic petechiae than those without petechiae, and (3) if the facedown position occurred more frequently among cases with more severe petechial hemorrhage of the thymus. We selected 199 SIDS cases from the San Diego SIDS Research Project database and grouped them as IP-present and IP-absent. Each case was analyzed with regard to the face position when found unresponsive or dead. Among these 199 cases, 37% were found face-down, which represents 51% of the 142 cases found prone. The two groups were similar with respect to age, sex, and rate of premature birth. Thirty-nine percent (39%) of the IP-present group and 9% of the IP-absent group were found in the facedown position (P = 0.057; 95% confidence interval for the difference = 0.3%, 40%). Cases were also grouped by severity of thymic petechiae and analyzed regarding face position. Neither age nor the facedown position was associated with greater severity of thymic petechiae. The wide confidence interval yielded by our analysis of IP limits our ability to clarify the precise pathophysiologic role of external oronasal obstruction in SIDS. While it remains possible that a subset of SIDS cases occur as a result of external obstruction, we are unable to generalize its importance. Internal airway obstruction and rebreathing with terminal gasping, both of which have been documented in sudden infant death, remain other possible scenarios leading to the production of IP.

Infant care practices in a metropolitan aboriginal population Bibbulung Gnarneep Team

OBJECTIVE

To describe sleeping position, room and bed-sharing, tobacco smoke exposure and infant feeding for a sample of Australian Aboriginal infants from a metropolitan area.

METHODS

Interviews with Aboriginal mothers who resided in the Perth metropolitan area and had given birth during a continuous 15-month study period. The interviews took place when the infants were approximately 6-12 weeks old and efforts were made to contact all eligible mothers. Results are presented as proportions with 95% confidence intervals.

RESULTS

Of all the eligible mothers (n = 515), 87% were contacted and 53% (n = 273) completed the interview. Of all the infants, 11% slept prone, 96% shared a room and 68% shared a bed; 65% of mothers smoked during pregnancy and 65% were smokers at the time of interview; 66% of the partners were smokers and 80% of the infants were regularly exposed to tobacco smoke; 89% of mothers initiated breast-feeding and 70% were breast-feeding at time of interview.

CONCLUSION

Prevalences of non-prone sleeping and breast-feeding are similar to the overall Western Australian population, whilst tobacco smoke exposure of the infants is markedly higher. Programs of community and family education and support are required urgently to decrease this exposure.

Body position, sleep states, and cardiorespiratory activity in developing low birth weight infants

The objective of this study was to determine the effects of body position (supine vs prone) on cardiorespiratory activity during quiet and active sleep in growing low birth weight (LBW) infants. The effect of postconceptional age on cardiorespiratory activity in the two positions was also evaluated. Fifty-one healthy, growing, appropriate for gestational age LBW infants (795-1600 g), ranging from 26-37 weeks in gestational age, were evaluated. All subjects were enrolled in an ongoing study of the effects of quality of dietary energy on the rate and composition of weight gain. Infants were randomly assigned to the supine or prone position for the first 3 h of the 6-h studies; the position was reversed for the second 3 h. Continuous recordings of cardiorespiratory activity were performed along with simultaneous minute by minute assignment of behavioral sleep state. Measurements of heart rate (HR), heart period variability (RR-SD), respiratory rate (f), and respiratory variability (fSD) were made each minute. Low birth weight infants had higher HR and f and lower RR-SD and fSD in the prone position compared to the supine position, during both quiet and active sleep. With increasing postconceptional age, positional differences in HR increased during quiet sleep and differences in RR-SD increased during both sleep states. These data demonstrate systematic differences in cardiorespiratory control related to body position during sleep. We speculate that such positional differences are due to variations in autonomic control, and may, in turn, contribute to variations in susceptibility to sudden infant death syndrome.

Maternal proximity and infant CO2 environment during bedsharing and possible implications for SIDS research

Sudden infant death syndrome (SIDS) is the leading cause of human infant mortality after the neonatal period in Western countries. Recently, child care practices have been shown to be important in determining infant vulnerability to SIDS. However, very little is known about the impact of parent-infant cosleeping on infant sleep physiology and behavior and SIDS risk. This reflects the failure of Western societal research paradigms to appreciate the human infant's evolutionary history of cosleeping, the recency of the emergence of solitary infant sleeping as a practice and the fact that parent-infant cosleeping is still the preferred sleeping arrangement for the majority of contemporary societies. Incorporating current hypotheses on the mechanisms of SIDS, we have hypothesized that the comparatively sensory-rich cosleeping environment might be protective against SIDS in some contexts. As a first step to characterize cosleeping environments, this investigation is aimed at assessing, in routinely bedsharing mothers and infants, their relative sleeping positions and the potential for sleeping in close face-to face proximity and for infant exposure to increased environmental CO2 produced by maternal respiration. The latter is important in that breathing elevated levels of CO2 can have diverse effects, ranging from respiratory stimulation at low levels to suffocation at very high levels. Two related laboratory studies were performed. In the first, all-night videotapes of 12 healthy, routinely bedsharing mother-infant pairs were analyzed for sleeping positions and time spent in face-to-face orientation and distances separating their faces. Infants were 11-15 wk old. Mothers predominantly positioned themselves on their sides facing their infants, with the infants placed either supine or on their sides. Mothers and infants slept oriented face-to-face for 64 +/- 27% (S.D.) of non-movement time, with distance less than 20 cm commonly separating their faces. In the second study, concentrations of CO2 in air were measured in six young women at distances of up to 21 cm from their nares. Peak expiratory CO2 concentrations remained above 1.0% at distances up to 9 cm and above 0.5% at 18 cm. Both baseline and peak CO2 levels were further increased at all distances when measured within a partial air pocket created to simulate a bedding environment sometimes seen during bedsharing. We conclude that during bedsharing there is potential for 1) a high degree of face-to-face orientation and close proximity and consequently 2) increased environmental CO2, as a result of maternal respiration, to non-lethal levels that might stimulate infant respiration. The close proximity would also maximize the sensory impact of the mother on the infant through other modalities. We also suggest that bedsharing may minimize prone infant positioning, a known risk factor for SIDS.

Sudden infant death syndrome: a hypothesis

A study of the strikingly low incidence of sudden infant death syndrome in Eastern countries revealed significant differences in infant handling thought to have an etiological bearing; therefore this writer suggested that adoption of certain Eastern methods of nursing may reduce the incidence of sudden infant death syndrome. A dramatic fall in incidence has resulted from implementing one of the suggestions made by the writer in 1983, namely the abandonment of the prone position, after initial opposition. The present hypothesis sets out to give a scientific explanation for this fall, and is a unified hypothesis explaining certain puzzling and disparate features of sudden infant death syndrome such as the remarkable winter incidence, age incidence, and the occurrence of sudden infant death syndrome during sleep, and is based on a postulated disturbance in thermoregulatory function (a unique hypothermia). Recommendations are made for evolving a test for sudden infant death syndrome-proneness and a possible method of treatment of a fatality within a short time frame.

Infant sleep position and the sudden infant death syndrome. A survey of pediatric recommendations

A questionnaire survey was conducted to assess the impact of the April 1992 American Academy of Pediatrics Task Force Statement, "Infant Positioning and SIDS," on the routine advice provided by pediatricians in Minnesota to families with newborn infants regarding sleep practices, including sleep position. There was a trend toward more discussion between all pediatric practice groups and families regarding infant sleep practices following the AAP Sleep Position Statement (P < 0.001-0.003). Prone sleep recommendations ranged from 9.2% for newborn infants to 21.4% for infants 6 months of age. Recommendations for the supine or lateral sleep positions predominated at all infant ages. Pediatricians in private practice were more likely to identify the AAP Statement as establishing a medicolegal standard (P < 0.05). We conclude that the 1992 AAP Statement has had a significant impact on the routine advice provided to families regarding infant sleep practices, including infant sleep position.

Has changing diagnostic preference been responsible for the recent fall in incidence of sudden infant death syndrome in South Australia?

OBJECTIVE

An apparent decrease in deaths attributed to sudden infant death syndrome (SIDS) has been noted in a number of diverse geographical areas during the past several years. At the same time the definition of SIDS has been in a state of flux and some observers have raised the possibility that the fall in SIDS deaths is due to diagnostic transfer rather than to a genuine decrease in numbers. The present study was undertaken to investigate this possibility.

METHODOLOGY

All sudden and unexpected deaths in infants under 1 year of age in South Australia during a 10 year period from 1984 to 1993 were reviewed.

RESULTS

The number of deaths due to SIDS fell from 40 in 1984 to 17 in 1993, with a maximum of 52 cases per year in 1987. In contrast, the number of cases of sudden death not due to SIDS remained under 10 per year. The overall infant death rate also fell, while the total number of births per year remained relatively unchanged.

CONCLUSIONS

The lack of major change in sudden infant death rates from other causes, combined with the fall in SIDS deaths, is not supportive of diagnostic transfer being a major determinant of the declining SIDS death rate. Therefore, other factors are likely to be responsible for the falling SIDS rate in this population.

Carbon dioxide concentrations in the environment of sleeping infants

In 22 infants continuous measurements were made of the concentration of carbon dioxide (CO2) in inspired air during sleep. Evidence was found of CO2 enrichment of inspired air in certain environmental conditions. The levels achieved were not sufficiently high to acutely endanger an infant. Carbon dioxide concentrations as high as 2-3% were observed in the prone position when the infant's head was under a blanket and when the lower face was obscured by bedding. Sleeping prone on a sheepskin also resulted in an increased concentration of CO2 but to a lesser extent than being under a blanket. In awake infants the presence of a pacifier also promoted an excess of CO2 in the inspired air, both in the prone and supine positions. The physiological and clinical implications of these findings, in relation to the Sudden Infant Death Syndrome (SIDS), are unknown and warrant investigation.