Proposal for mechanisms of protection of supine sleep against sudden infant death syndrome: an integrated mechanism review

Abstract

Supine sleep decreases sudden infant death syndrome (SIDS) incidence, however the mechanisms for this are unclear. The triple risk model for SIDS requires that one or more underlying abnormalities of breathing or autonomic control are present; these are rare, but brainstem defects are found in most SIDS cases. Supine sleep increases sympathetic nervous system tone, and level of state organization, and may therefore act as a stressor. This is evidenced by physiological arousal, and by delayed neurodevelopment in supine compared to prone sleepers. It is argued here that prone sleep position is the biological normative standard in healthy infants, supporting autonomic regulation. During rapid eye movement (REM) sleep (and other circumstances), a parasympathetic-mediated adverse autonomic event (AAE) may be spontaneously triggered. In healthy infants, gasping initiates autoresuscitation and recovery. Hypothesis: the underlying vulnerability to SIDS is specific to autoresuscitation from an AAE, the initial serotonin-dependent gasp is commonly compromised. Serotonin metabolism defects also influence sleep architecture, increasing the likelihood of AAE. The mechanism whereby supine sleep decreases SIDS may therefore be a stressor effect, disturbing sleep architecture to decrease REM and AAEs, and increasing sympathetic tone, which may prevent and counteract the purely parasympathetic-mediated AAE, thereby decreasing the risk of SIDS.

Effect of sleeping position on arousals from sleep in preterm infants

“…Our results showed that, of the four sleeping positions, the preterm infants remained in the supine position for a longer mean time, which was also the most frequent position. These findings were consistent with criteria in the international literature for preventing SIDS (Bergman, ; Horne, Bandopadhayay, et al., ). Global awareness campaigns have advocated the supine or side position as being the safest option, which has already contributed to a 50% reduction in mortality, as well as in the incidence of SIDS (Bergman, ; Horne, Bandopadhayay, et al., ; Sahni et al., ).…”

Microbiome–Gut–Brain Axis: A Pathway for Improving Brainstem Serotonin Homeostasis and Successful Autoresuscitation in SIDS—A Novel Hypothesis

“…Sudden infant death syndrome is associated with multiple serotonergic defects including serotonin deficiency and DMV abnormalities (15–18, 62). We briefly review the vagal afferents, brainstem respiratory neurons, and the medullary serotonergic system.…”

“…The initial self-initiated gasp during such an event is dependent of optimal serotonin homeostasis in the brain, which is undermined in SIDS. Imbalance in serotonin homeostasis alters sleep rhythm, thus increasing the chances of AAE (15). …”

Colecho en el hogar, lactancia materna y muerte súbita del lactante. Recomendaciones para los profesionales de la salud. Texto completo

“…47 Sin embargo, hay otros niños que pueden ser vulnerables -por alteraciones genéticas en los neurotransmisores-, a los que no podemos identificar en la actualidad. 48 Cuando el recién nacido está en contacto piel a piel con su madre, puede estar en posición prona sobre el torso materno. En estas circunstancias, se debe cuidar que la cabeza del bebé esté girada hacia un lado con la nariz y la boca desobstruidas y con el cuello no flexionado.…”