A review of the anatomy of the upper airway in early infancy and its possible relevance to SIDS
Section snippets
Shape of the upper airway in infancy
The upper airway, between the external nares and the trachea, is obviously crucial to the delivery of air to the lungs, and thus of oxygen to the whole body. The shape of the upper airway and the forces acting upon it in infancy are not the same as in adult life. At birth the head is approximately one quarter of the total length of the infant. The brain is nearing adult size, as are the eyes, whilst the face, the maxilla and especially the mandible are small and undeveloped (Fig. 1a). The
General principles
The epidemiological identification of a number of risk factors for sudden infant death syndrome (SIDS) such as prone sleeping, and their subsequent reduction in the general population has been associated with a dramatic fall in the incidence of SIDS [9], [10]. Nevertheless, unexpected infant deaths still occur that are not associated with these known epidemiological risk factors. Obstruction or restriction of the upper airway is one likely cause of such cases. In practice virtually all
Examination and investigation for possible upper airway inadequacy
The most obvious facial clue to an upper airway problem is often that the infant has a very small jaw (is micrognathic) [11], [49]. Babies with inadequate upper airways often have an anxious expression and have a ‘fat chops’ look, because the posteriorly positioned tongue bulges the infant's submental region as there is no sufficient room for it between the mandible and the soft palate. These facial characteristics have been noted in families who have experienced SIDS or ALTEs in subsequent
Summary
In conclusion, unexpected infant deaths and ALTEs continue to occur. Although many other potential causes will contribute to these problems, there is increasing evidence that a significant proportion may be related to obstruction or restriction of the upper airway during sleep. This review has highlighted features of the development and anatomy of the young infant that predispose to functional/positional and structural restriction or obstruction of the upper airway. These data help guide the
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Cited by (28)
How might non nutritional sucking protect from sudden infant death syndrome
2020, Medical HypothesesCitation Excerpt :As mentioned in the “Pacifier protective effect” section, the exogenous stressor (as per the “triple risk model”) for between 60 and 90% of SIDS cases who potentially benefit from pacifier use would necessarily be classified as anoxic if our hypothesis is correct. There exist evidence that sleep disordered breathing, leading to anoxia, could play a significant role in the pathophysiology of SIDS .[13,22–26] Oropharynx collapsibility during REM sleep,[24] airway compliance,[27] and soft palate size,[24] among other risk factors, have been identified in support of upper airway collapse, as seen in OSA, as a primary respiratory control derangement in SIDS.
Gut microbiome in sudden infant death syndrome (SIDS) differs from that in healthy comparison babies and offers an explanation for the risk factor of prone position
2014, International Journal of Medical MicrobiologyCitation Excerpt :This has seemingly been overlooked by mainstream SIDS researchers investigating a relationship between SIDS and respiratory or brainstem physiology. However those researchers continuing to investigate the microbiology of SIDS (Goldwater, 2011; Goldwater and Bettelheim, 2013; Lindsay et al., 1993; Murrell et al., 1993) have provided evidence to supplant the old theories of respiratory compromise, etc. (Krous, 1984; Tonkin et al., 2002) with a congruent patho-mechanism of SIDS. Given that evidence favours the infection model of SIDS and the recent findings of differences in gut microflora between SIDS and healthy babies especially in regard to Staphylococcus aureus enterotoxins (Highet et al., 2009) and toxigenic E. coli (Bettelheim et al., 1990; Bettiol et al., 1994) but also Cl.
The evolution and development of human swallowing: The most important function we least appreciate
2013, Otolaryngologic Clinics of North AmericaCitation Excerpt :The combination of subsequent, postnatal CNS maturation and developmental changes in respiratory patterns may predispose the infant to several developmentally related problems. The sudden infant death syndrome (SIDS), for example, may be related to the fragility of these first postnatal upper respiratory changes, reflecting prenatal insults to the brainstem nuclei involved in aerodigestive neuromuscular control.25,27 The precise time of the shifts that occur in breathing patterns, their relationship to laryngeal changes, and the neurophysiologic mechanisms that accompany them are obviously crucial questions that are still poorly understood and require more specific and detailed study.
Otolaryngological aspects of sudden infant death syndrome
2012, International Journal of Pediatric OtorhinolaryngologyCitation Excerpt :The age of 4–6 months is considered a cardinal transitional period from obligate nasal breathing to oral respiration. The posterior aspect of the tongue gradually slides down and forms the new anterior border of the oropharynx, due to its relative large size within the oral cavity [10]. The larynx and epiglottis descend away from the soft palate down in the neck to create a common passage for air, food, and liquid (Fig. 1).
Smaller mandibular size in infants with a history of an apparent life-threatening event
2006, Journal of PediatricsCitation Excerpt :In addition, a large tongue can partially occlude the airway.11,14 Tonkin et al noted that an infant’s airway is vulnerable to unbalanced external forces that tend to narrow the airway.11 For example, Stark and Thach showed that mandibular pressure from a face mask can cause backward displacement of the jaw leading to airway obstruction.15
Physiology of Breathing and Related Pathological Processes in Infants
2003, Seminars in Pediatric Neurology