Elisabeth Rebuffat

Ondine-Hirschsprung syndrome (Haddad syndrome). Further delineation in two cases and review of the literature.

Two unrelated children with congenital central hypoventilation syndrome (CCHS-Ondine syndrome) and long segment Hirschsprung disease are reported. Patient 1, a girl, is still alive at 3 years. Patient 2, a boy, died of viral pneumonia at 5.5 years. Continuous mechanical ventilation was necessary for months and those children could never be weaned from the respirator during sleep. Seventeen cases of this complex neurocristopathy are reviewed. Only six children (including our cases) survived beyond 2 years of age. Hypotonia, delay in developmental milestones or epilepsy were frequently observed. Ventilator dependency does not improve with time. Multifocal congenital neuroblastoma occurred in two children. Aetiology is unknown.

Lack of temporal relation between acid reflux in the proximal oesophagus and cardiorespiratory events in sleeping infants

We studied sleeping infants in order to investigate whether a temporal relation exists between acid reflux extending to the proximal portion of the oesophagus and cardiorespiratory events. One hundred infants with occasional regurgitations were studied: 50 infants admitted after an apparently life-threatening event (ALTE) that occurred during sleep and that remained unexplained despite medical investigation, and 50 asymptomatic infants (non-ALTE). The infants had a median age of 8 weeks (range 4–26 weeks); 54 were boys. In each child a pH probe was placed in the proximal portion of the thoracic oesophagus, under radiological control. Polygraphic monitoring of state of alertness, cardiorespiratory activity, and proximal oesophageal pH changes was conducted continuously during 1 night. The data were analysed blind. In 80 infants a total of 186 decreases in oesophageal pH below 4 units were seen; 37% occurred during wakefulness, and 40% during rapid eye movement (REM) sleep. A total of 7029 central and 61 obstructive apnoeas were monitored, mainly during REM sleep. Within 5 min before, and 5 min after the drops in pH, there was no difference in the number, or the duration of bradycardia, central, mixed, or obstructive apnoea. The infants with an ALTE could not be differentiated from the non-ALTE infants for any of the variables studied. It is concluded that spontaneous acid refluxes extending to the proximal portion of the oesophagus during sleep are usually not temporally related with the development of apnoeas or bradycardias.

Mechanisms of obstructive sleep apneas in infants

During sleep, infants with obstructive sleep apneas are characterised by snoring, laborious breathing, and profuse sweating. During wakefulness, they may have breath-holding spells, and during feeding, difficult breathing and swallowing coordination. Abnormal weight, difficult growth, and recurring ear infections may also develop. During sleep apneas, cinefluoroscopy shows approximation of tongue and hypopharyngeal tissues, with an obliteration of the air space. The obstructed breaths occur mainly in REM, and light NREM sleep, associated with total short sleep time, and frequent arousals. Preterm infants, and term neonates are more prone to obstructive apneas than older healthy infants. Apneas are more frequently seen in boys and in case of excess in body weight. Obstructive apneas are frequently associated with upper airway anatomic abnormalities: malformations, soft tissue infiltration, and neurologic lesions impairing muscle contractions. Alterations of the autonomic nervous control may induce airways obstructions. Contributing factors include mucopolysaccharide storage disease, hypothyroidism, or Downs syndrome. Superimposed factors may occur, such as nasal obstruction, secretions in the airways, or tissue edema. Pressure- and chemo-sensitive reflexes may also favor obstruction. Environmental factors also contribute to the development of sleep apneas: body position, neck flexion, sleep deprivation, or the effects of sedative drugs.

Brief airway obstructions during sleep in infants with breath-holding spells.

We investigated the possibility that infants with breath-holding spells have breathing disorders during sleep. Seventy-one breath holders with a median age of 14 weeks were selected from a well babies clinic because of their histories: 34 infants without loss of consciousness, and 37 with loss of consciousness (21 of the latter had had cyanotic spells, 14 pallid spells, and 2 combined cyanotic and pallid spells). For each breath holder, one control infant without a history of breath holding was chosen from the same clinic. All infants were healthy and had no known cause of disrupted breathing during sleep. Their histories indicated that the breath holders were covered with sweat during sleep (p = 0.005) or wakefulness (p = 0.006) significantly more often than were the control infants. The infants were studied during a one-night monitoring session, and the 142 sleep recordings were analyzed without knowledge of the history. The breath holders had significantly less nonrapid eye movement (stage III) sleep, more indeterminate sleep, more arousals, and more sleep-stage changes than the control infants had. Central apneas were evenly distributed in the two groups. Airway obstructions were found in 41 breath holders and six control infants; the obstruction lasted longer in the breath holders. The infants with airway obstruction during sleep snored more often (p = 0.023) and sweated more (p = 0.035) during sleep. The water evaporation rate, measured on the forehead with an evaporation meter, was significantly greater in the breath holders (p = 0.001). Ocular compression induced longer asystoles in the infants with pallid syncopes than in either those with cyanotic syncopes (p = 0.036) or those without loss of consciousness (p = 0.031). We conclude that the obstructed breathing during both wakefulness and sleep could be related to a common immature breathing control.

Effects of body movement restraint on cardiac response to auditory stimulation in sleeping infants

When exposed to an unfamiliar and sudden noise, infant rodents may show an abrupt bradycardia, as part of a “fear‐paralysis response”. The response is enhanced by body movements restraint. To investigate if this reaction is seen in humans, 15 normal infants with a median age of 12 weeks were studied polygraphically. They were exposed to a 100‐dB (A) white noise, while sleeping in REM sleep. Each infant was studied in both “unrestrained” and “restrained’ conditions. Restraint of body movement was obtained by means of sand bags and tightly‐binding bed sheets. During movement restraint, the infants had a significantly greater and earlier decrease in heart rate compared with during the unrestrained condition. No infant had a minimal heart rate less than 95 beats/min. The present observation raises questions about the possible unfavorable effects of tightly wrapped bed sheets around sleeping infants.

Problems in management of infants with an apparent life-threatening event.

The following notes discuss some aspects of the management of infants with an apparent life-threatening event. These are based on articles and some reviews published in the recent literat~rel-~ as well as on local experience. These notes are therefore liable to be both interpretative and not exhaustive. It is hoped that they can nevertheless contribute to the information of those interested in the management of infants thought to have survived a possible life-threatening event.

Home monitors for infants: use, misuse, and “over-the-counter” use

The prevalence of “over-the-counter” monitors, was surveyed in infants referred to five Belgian paediatric centres between September 1987 and March 1988 for evaluation of their risk for sudden infant death (SID). Questionnaires were collected from 1625 families. Of the infants, 8.9% were already being monitored at home. For 78.1% of the infants no medical advice had been solicited, and for 21.9%, a paediatrician or a general practitioner had advised home monitoring without previous evaluation. Forty of 824 infants referred with no history of SID, and no history of apparent life-threatening event (ALTE), were monitored (4.8%). Monitoring was started for 3.8% (5 out of 130) of the infants who had lost a cousin or an uncle to SID, and for 22.2% (69 of 310) of the younger siblings of a SID victim. Of the 341 infants who had presented with an ALTE, monitoring was started in 32 (9.4%). The infants were monitored with respiratory monitors only, and in 86% of the monitors, the alarm delay had been regulated unnecessarily low.

Recent advances in sudden infant death syndrome: Possible autonomic dysfunction of the airways in infants at risk

Epidemiological studies of sudden infant death syndrome (SIDS) reveal a progressive increase in the incidence of cases, suggesting that the in utero environment and postneonatal care were less than optimal. Subtle differences in symptoms could indicate that, since birth, the SIDS infants are different from control infants, some having an autonomic dysfunction of the airway controls. These observations could contribute to a better understanding of some of the causes of sudden death in infants and could eventually lead to new therapeutic approaches.

Continuous transepidermal water loss measurement in sleeping infants.

ABSTRACT. Transepidermal water evaporation rate was measured continuously in 8 infants with the use of an evaporimeter during one night of polygraphic sleep recording. Evaporation rates were significantly lower during REM than during NREM sleep. In both sleep stages it decreased during the night with the lowest values between 02.00 and 04.00 h. Evaporation values showed cyclic changes which were studied by measuring minute‐by‐minute differences between the maximum and the minimum values (the “amplitude variability”) and the number of evaporation peaks per minute (the “peak density”). Both the “amplitude variability” and the “peak density” were smaller in REM than in NREM sleep. The “amplitude variability” decreased during the night with lowest values seen between 02.00 and 04.00 h. These changes in evaporation rates could reflect autonomic nervous system activity as well as basal metabolic activity and should be taken into account whenever such measurements are performed in sleeping infants.

Decreased growth hormone response to glucagon in infants after an apnea of infancy.

We studied glucagon-induced growth hormone secretion in 9 patients with apnea of infancy and in 55 siblings of children who had died of sudden infant death syndrome, who were included as a comparison group. We observed a 33% decrease in growth hormone secretion in patients with apnea of infancy. However, linear growth remained normal. This finding could be related to either repeated episodes of hypoxia or to abnormal maturation of the autonomous nervous system.