SIDS Risk: It's More Than Just the Sleep Environment

The multiagency approach to Sudden Unexpected Infant Deaths (SUID): eleven years' experience in the Tuscany Region

Background

The Sudden Unexpected Infant Death Syndrome (SUID) is one of the leading causes of mortality in the first year of life. The aim of this work was the retrospective evaluation of the incidence of SUID and the effectiveness of the multiagency approach to this phenomenon in the Tuscany Region.

Methods

Data were obtained from the regional registry of SUID cases in the period 2009–2019. The registry contains both sudden unexpected deaths in the first week of life (Sudden Unexpected Early Neonatal Deaths - SUEND), and those occurring after the first week up to 1 year of age (SUID).

Results

In this timeframe a total of 73 sudden unexpected deaths occurred in our region; 32 were Unexplained (i.e. Sudden Infant Death Syndrome - SIDS), 24 Explained, 10 Undetermined, and 7 SUEND. Autopsies were performed in 91% of cases, and in 95% of these by three groups of selected pathologists according to our protocol.

We found a low incidence of SUID (0.21 ‰), and SIDS deaths accounted for 0.1‰ of live births (48% of cases) with a high prevalence of infants of non-Italian ethnicity (38% of cases). Bereaved families were able to receive psychological support from mental health professionals and have contact with the family association, Seeds for SIDS. Audits were organized when post-mortem examinations were not carried out or carried out incorrectly in procedural terms, and when the diagnosis was particularly uncertain.

Conclusions

This paper first provides data on SUID mortality based on complete post-mortems in an Italian region. According to these findings we can state that our approach is effective both in terms of correctly performed autopsies and support for bereaved families. Future efforts are necessary to further reduce the incidence of SUID especially among non- Italian infants. An improvement action is also recommended for ensuring a more accurate and consistent picture of the circumstances of death.

The final approval of the National Protocol for the management of SUID cases is therefore strongly advocated in order to improve surveillance in this specific field and abolish disparities among the Italian regions.

Prematurity and Sudden Unexpected Infant Deaths in the United States

BACKGROUND AND OBJECTIVES

Prematurity, a strong risk factor for sudden unexpected infant death (SUID), was addressed in recommendations by the American Academy of Pediatrics in 2011 for safe sleep education in NICUs. We documented associations between gestational age (GA) and SUID subsequent to these guidelines.

METHODS

Using the 2012-2013 US linked infant birth and death certificate period files, we documented rates per live births of sudden infant death syndrome, ill-defined and unspecified causes, accidental suffocation and strangulation in bed, and overall SUID by GA in postneonatal, out-of-hospital, and autopsied cases; compared survivors and cases; and estimated logistic regression models of associations between GA and SUID.

RESULTS

SUID cases were more likely than survivors to be <37 weeks' GA (22.61% vs 10.79%; P < .0001). SUID rates were 2.68, 1.94, 1.46, 1.16, 0.73, and 0.51 per 1000 live births for 24 to 27, 28 to 31, 32 to 33, 34 to 36, 37 to 38, and 39 to 42 weeks' GA, respectively. Logistic regression models additionally indicated declines in the risk for SUID as GA increased. Prenatal smoking, inadequate prenatal care, and demographics associated with poverty were strongly associated with SUID.

CONCLUSIONS

Despite the 2011 American Academy of Pediatrics recommendations for increased safe sleep education in the NICUs, SUID rates were inversely associated with GA in 2012 to 2013, suggesting that risk of SUID associated with prematurity has multiple etiologies requiring continued investigation, including biological vulnerabilities and the efficacy of NICU education programs, and that strategies to reduce SUID should be multifaceted.

Interactive effects of maternal cigarette smoke, heat stress, hypoxia, and lipopolysaccharide on neonatal cardiorespiratory and cytokine responses

Maternal cigarette smoke (CS) exposure exhibits a strong epidemiological association with Sudden Infant Death Syndrome, but other environmental stressors, including infection, hyperthermia, and hypoxia, have also been postulated as important risk factors. This study examines whether maternal CS exposure causes maladaptations within homeostatic control networks by influencing the response to lipopolysaccharide, heat stress, and/or hypoxia in neonatal rats. Pregnant dams were exposed to CS or parallel sham treatments daily for the length of gestation. Offspring were studied at postnatal days 6-8 at ambient temperatures (T_a) of 33°C or 38°C. Within each group, rats were allocated to control, saline, or LPS (200 µg/kg) treatments. Cardiorespiratory patterns were examined using head-out plethysmography and ECG surface electrodes during normoxia and hypoxia (10% O₂). Serum cytokine concentrations were quantified from samples taken at the end of each experiment. Our results suggest maternal CS exposure does not alter minute ventilation (V̇e) or heart rate (HR) response to infection or high temperature, but independently increases apnea frequency. CS also primes the inflammatory system to elicit a stronger cytokine response to bacterial insult. High T_a independently depresses V̇e but augments the hypoxia-induced increase in V̇e Moreover, higher T_a increases HR during normoxia and hypoxia, and in the presence of an immune challenge, increases HR during normoxia, and reduces the increase normally associated with hypoxia. Thus, while most environmental risk factors increase the burden on the cardiorespiratory system in early life, hyperthermia and infection blunt the normal HR response to hypoxia, and gestational CS independently destabilizes breathing by increasing apneas.