Sleep disordered breathing improvement prevents worsening of autonomic dysfunction in children with Down syndrome.

BACKGROUND: Resolution of sleep disordered breathing (SDB) in typically developing children normalises heart rate variability (HRV), a measure of autonomic control, to that of non-snoring controls. Children with Down Syndrome (DS) have dampened heart rate variability (HRV) but the effect of treatment is not known. To assess the effect of improvement of SDB on autonomic control we compared HRV in children with DS whose SDB improved over 2 y, to those whose SDB did not improve. METHODS: 24 children (3-19 y) had a baseline and follow-up polysomnographic study 2 y later. Improved SDB was defined as a reduction in obstructive apnea hypopnea index (OAHI) to ≤ 50% of baseline. Children were grouped into Improved (n = 12) and Unimproved (n = 12). Power spectral analysis of the ECG determined low frequency (LF), high frequency (HF) power and the LF/HF ratio. Seven children in the Improved and 2 in the Unimproved group were treated following the baseline study. RESULTS: In the Unimproved group at follow-up, LF power was lower compared to baseline during N3 and Total Sleep (p < 0.05 for both). HF power was lower during REM (p < 0.05). HRV remained unchanged between studies in the Improved group. CONCLUSION: Autonomic control worsened as indicated by lower LF and HF power in children whose SDB was not improved. In contrast, in those children with improved SDB, autonomic control remained the same, suggesting improvement in SDB severity prevents further worsening of autonomic control in children with DS.

Continuous oximetry recordings on the first post-operative night after pediatric adenotonsillectomy-a case-control study.

BACKGROUND: Children with obstructive sleep apnea (OSA) with recurrent dips in oxygen saturation (SpO2) during sleep are known to be at increased risk of post-operative airway compromise after adenotonsillectomy (AT). We aimed to determine the extent of desaturation on the first post-operative night in children known to have recurrent desaturation pre-operatively and to compare the extent of desaturation in that group with results in children known to have normal oximetry recordings pre-operatively. METHODS: Prospective sequential recruitment of 57 children who had overnight oximetry performed on the first night after adenotonsillectomy was undertaken, including 28 with a McGill Oximetry Score (MOS) of 2-4 pre-operatively (high risk group) and 29 with a normal/inconclusive pre-operative MOS (low risk group). Oximetry parameters (mean SpO2, SpO2 nadir, and rates of SpO2 dips below 90% and dips of ≥4%) were compared to the pre-operative oximetry result. Demographic and clinical factors, and the occurrence of post-operative complications, were derived from the medical record. RESULTS: In the high risk group, the MOS improved in 23/28 children, but remained abnormal in 82%. Conversely, in the low risk group 26/29 (90%) had a normal post-operative oximetry. The remaining 3, all of whom had severe OSA on pre-operative polysomnography, had a lowered baseline SpO2 post-operatively. Mean SpO2 was slightly lower post-operatively in both groups. In the high risk group, all other SpO2 measures improved post-operatively. Respiratory adverse events were more common in the high risk group as expected (39% compared to 3% in the low risk group, p = 0.001). An adverse event requiring clinical intervention was significantly more likely if the post-operative oximetry was abnormal (result unknown to the treating team), occurring in 73% of children with an abnormal compared with 32% of children with a normal post-operative oximetry (p = 0.002). CONCLUSION: Most children with an abnormal oximetry pre-operatively continued to have an abnormal oximetry on the first night after AT, albeit somewhat improved. While adverse events were more frequent in children with an abnormal post-operative oximetry, half (54%) did not suffer a clinical respiratory adverse event despite having repetitive desaturations on downloadable oximetry. These findings support close clinical observation of children at high risk of complications post-operatively, especially those with abnormal oximetry pre-operatively, rather than focusing on recurrent dips in SpO2 on post-operative oximetry downloads in the absence of clinically evident complications.

Role of ventilatory control instability in children with sleep-disordered breathing.

BACKGROUND AND OBJECTIVE: The contribution of non-anatomical factors, such as ventilatory control instability (i.e. LG), to the pathogenesis of obstructive SDB in children is unclear. Therefore, we aimed to identify the relationship between LG and severity of SDB, demographic, anthropometric and anatomical characteristics in a clinically representative cohort of children. METHODS: Children (aged 3-18 years) with various severities of SDB (n = 110) and non-snoring controls (n = 36) were studied. Children were grouped according to their OAHI. Anthropometric and upper airway anatomical characteristics were measured. Spontaneous sighs were identified on polysomnography and LG, a measure of the sensitivity of the negative feedback loop that controls ventilation, was estimated by fitting a mathematical model of ventilatory control to the post-sigh ventilatory pattern. RESULTS: There was no difference in LG between controls and any of the SDB severity groups. However, LG was significantly lower in children with larger tonsils (tonsil grade 4) compared with children with smaller tonsils (tonsil grade 1) (median LG (range): 0.25 (0.20-0.42) vs 0.32 (0.25-0.44); P = 0.009) and in children with a modified Mallampati score of class III/IV compared with class I (0.28 (0.24-0.33) vs 0.37 (0.27-0.44); P = 0.009). CONCLUSION: A direct relationship was not found between the severity of paediatric SDB and LG. However, an altered ventilatory control sensitivity may contribute to SDB in a subgroup of children depending on their degree of anatomical compromise of the airway.

The impact of sleep disordered breathing on cardiovascular health in overweight children.

BACKGROUND: Up to 50% of overweight/obese children have obstructive sleep apnea (OSA) compared to up to 6% of normal weight children. We compared cardiovascular variables between normal weight and overweight/obese children with and without OSA, and controls. METHODS: Seventy-four referred children and 24 normal weight non-snoring controls (8-18 years) were recruited. Referred children were grouped according to their obstructive apnea hypopnea index (OAHI): OSA (>1 event/h) or primary snoring (PS ≤ 1 event/h) and whether they were normal weight (BMI z-score <1.04) or overweight/obese (BMI z-score ≥ 1.04). Wake blood pressure (BP), heart rate (HR), and pulse transit time (PTT, an inverse continuous surrogate measure of blood pressure) during sleep were recorded. RESULTS: Wake BP was higher in the overweight/obese OSA group than in the control, normal weight PS, and overweight/obese PS groups (p < 0.05 for all). During sleep, BP, and HR were elevated in the overweight/obese OSA group compared to those in non-snoring controls (p < 0.05). More children who were overweight/obese had reduced BP and HR dipping from wake to sleep than normal weight children. The BMI z-score predicted HR and PTT when asleep and both age and BMI z-score predicted BP when awake. CONCLUSION: This study showed that BMI has both combined and independent effects on BP and HR in children with OSA. We have previously shown that treatment of OSA reduces BP and suggest that treatment of OSA in the growing number of overweight/obese children may improve cardiovascular outcomes.

Risk factors for obstructive sleep apnoea in Australian children.

AIM: This study aims to determine whether demographic or clinical factors predict obstructive sleep apnoea (OSA) severity in Australian children. METHODS: Demographic details and medical histories of 301 Australian children (3-17 years old) referred for assessment of OSA were examined retrospectively. Children underwent overnight polysomnography and were classified as having primary snoring (PS) (obstructive apnoea hypopnoea index (OAHI) ≤ 1 event per hour; n = 150), mild OSA (>1 OAHI ≤ 5 events per hour; n = 76) or moderate/severe (MS) OSA (OAHI > 5 events per hour; n = 75). Information obtained from parent-report questionnaire determined the predictive value of the following factors for determining OSA severity: gender, ethnicity, body mass index, asthma and/or allergic rhinitis, socio-economic status and parental smoking status (mother/father/both). Chi-squared analyses were used to compare the distribution of the demographic and clinical factors across the three groups. Statistically significant risk factors were subsequently entered into logistic regression analysis. RESULTS: Ethnicity and parental smoking were significant risk factors for MS OSA. Children with non-Caucasian ethnicity were 36% more likely than Caucasian children to be diagnosed with MS OSA than PS (P = 0.002). Children with fathers who smoked were 53% more likely to have MS OSA than PS compared with those with fathers who did not smoke (P = 0.008). Obesity was associated with OSA severity in primary school-aged children only. Gender, socio-economic status and history of asthma and/or allergic rhinitis were not risk factors. CONCLUSIONS: Non-Caucasian ethnicity, paternal smoking and obesity in older children were associated with an increased risk of polysomnography-confirmed MS OSA in Australian children.

Clinical outcomes in a high nursing ratio ward setting for children with obstructive sleep apnea at high risk after adenotonsillectomy.

BACKGROUND: In 2012 clinical management of children having adenotonsillectomy (AT) for suspected obstructive sleep apnea (OSA) at our tertiary centre changed based on previous research: children with severe obstructive sleep apnea (OSA) at increased risk of post-operative respiratory adverse events (AE) identified using home overnight oximetry or polysomnography (PSG) were managed post-operatively in a high nurse/patient ratio unit in the ward (high acuity unit, HAU) rather than in the intensive care unit (ICU) as previously. OBJECTIVES: To examine the post-operative respiratory AE post AT in HAU. METHODS: A retrospective audit was performed of children having AT on the HAU list from Oct 2012-Sept 2014, identifying clinical information, pre-operative testing for OSA and post-operative course. RESULTS: 343 children underwent elective adenotonsillectomy at our tertiary centre in the study period, of whom 79 had surgery on the HAU list (16F; median age 4.2year (range 1.2-14.7); median weight-for-age centile 77.9% (IQR 44-98.7%)). 75 had moderate/severe OSA by oximetry (n=44) or PSG (n=31) criteria. 77 of 79 children had oxygen therapy in the recovery room (median 20min, IQR 15-40min). 18 (23%) had at least one AE outside the recovery room, which were observed (n=2) or treated with oxygen therapy (n=14) or repositioning (n=2). Obesity increased the risk of an AE (10/25 obese vs 8/54 non obese, p=0.01), as did the presence of a major comorbidity (5/9 with comorbidity vs 13/70 without, p=0.03). There were no admissions from the HAU to ICU. 63 patients (83%) stayed only one night in hospital (median 1d, range 1-5d). CONCLUSIONS: In a cohort of children with known moderate-severe OSA, post-operative AE after AT were all managed in the HAU. Post-operative care in HAU provides safe and effective care for high-risk children post-AT, minimizing admissions to ICU.

Long-Term Improvements in Sleep and Respiratory Parameters in Preschool Children Following Treatment of Sleep Disordered Breathing.

STUDY OBJECTIVE: Sleep disordered breathing (SDB) in preschool-aged children is common, but long-term outcomes have not been investigated. We aimed to compare sleep and respiratory parameters in preschool children to examine the effects of treatment or non-treatment after 3 years. METHODS: Children (3-5 years) diagnosed with SDB (n = 45) and non-snoring controls (n = 30) returned for repeat overnight polysomnography (39% of original cohort), 3 years following baseline polysomnography. Children with SDB were grouped according to whether they had received treatment or not. SDB resolution was defined as an obstructive apnea hypopnea index (OAHI) ≤ 1 event/h, no snoring detected on polysomnography and habitual snoring not indicated by parents on questionnaire. RESULTS: Fifty-one percent (n = 23) of the children with SDB were treated. Overall, SDB resolved in 49% (n = 22), either spontaneously (n = 8) or with treatment (n = 14). SDB remained unresolved in 39% (n = 9) of those treated and 64% (n = 14) of the children who were untreated. Two of the non-snoring controls developed SDB at follow-up. The treated group had significantly lower OAHI (p < 0.01), respiratory disturbance index (p < 0.001), total arousal and respiratory arousal indices (p < 0.01 for both) at follow-up compared with baseline. There were no differences between studies for the untreated group. CONCLUSIONS: Although treatment resulted in an improvement in indices related to SDB severity, 39% had SDB 3 years following diagnosis. These findings highlight that parents should be made aware of the possibility that SDB may persist or recur several years after treatment. This is relevant regardless of the severity of SDB at baseline and the treatment given.

Sleep and fatigue in pediatric oncology: A review of the literature.

Cancer in children has detrimental effects on sleep patterns and sleep quality, which in turn impacts on the perception of, and the ability to cope with, the emotional and physical challenges associated with both the disease and its treatment. This places an added burden on their quality of life that can last many years beyond diagnosis and treatment. In addition to the effect of the cancer itself, surgery, chemotherapy and radiotherapy can all contribute both short and long term to sleep disruption. Sleep disorders have also been associated with pain, fatigue, medication and hospitalisation in children suffering from cancer. This review will explore the relationship between childhood cancer and associated sleep disorders, in the acute stage of diagnosis, during treatment and in the years following. We will discuss the possible causes and the current treatment modalities used to treat sleep disorders in children with cancer, and in childhood cancer survivors. It has been estimated that the recent advances in treatment have improved the overall five year survival rate for all childhood cancers to over 80%, with some cancers achieving a near 100% cure rate such as early stage Wilms' tumour. Thus, recognition and appropriate treatment of associated sleep disorders is essential to optimise long term quality of life.

Screening for obstructive sleep apnea in children with Down syndrome.

OBJECTIVE: To compare symptoms of obstructive sleep apnea (OSA) and polysomnography (PSG) results in children with Down syndrome and typically developing children. STUDY DESIGN: A total of 49 children with Down syndrome referred for PSG between 2008 and 2012 were matched with typically developing children of the same sex, age, and OSA severity who had undergone PSG in the same year. A parent completed a sleep symptom questionnaire for each child. Sleep quality and measures of gas exchange were compared between the matched groups. RESULTS: The 98 children (46 females, 52 males) had mean age of 6.2 years (range, 0.3-16.9 years). Fourteen children had primary snoring, and 34 had OSA (9 mild, 7 moderate, and 19 severe). Children with Down syndrome had more severe OSA compared with 278 typically developing children referred in 2012. Symptom scores were not different between the matched groups. Those with Down syndrome had a higher average pCO2 during sleep (P = .03) and worse McGill oximetry scores. CONCLUSION: Compared with closely matched typically developing children with OSA of comparable severity, children with Down syndrome had a similar symptom profile and slightly worse gas exchange. Referred children with Down syndrome had more severe OSA than referred typically developing children, suggesting a relative reluctance by parents or doctors to investigate symptoms of OSA in children with Down syndrome. These findings highlight the need for formal screening tools for OSA in children with Down syndrome to improve detection of the condition in this high-risk group.

Routine post-operative intensive care is not necessary for children with obstructive sleep apnea at high risk after adenotonsillectomy.

OBJECTIVES: Post-operative respiratory adverse events (AE) are frequent in children having adenotonsillectomy (AT) for obstructive sleep apnea (OSA). Many hospitals have a policy of routine admission to the intensive care unit (ICU) after surgery for children at highest risk. We aimed to determine the frequency and severity of post-operative AE in children admitted to ICU, to assess the appropriateness of this care plan. METHODS: A retrospective chart review was carried out all children admitted to the pediatric intensive care unit after AT for OSA from January 2007 to December 2009. AE were classified as mild, including requirement for supplemental O2 or repositioning to improve airway or severe, including bag and mask ventilation, CPAP, re-intubation, placement of oropharyngeal airway or unplanned ICU admission for airway compromise. RESULTS: 72 children were identified (21 female, median age 2.8 years). There were 29 AE in 26 patients (36%), including 23 (31.9%) who suffered a mild AE and 6 (8.3%) who had a severe AE. Age, sex, the presence of co-morbidity or the presence of severe OSA did not predict severe AE in this group. Median time to first AE was 165min. Four of the six severe AE occurred in the post-anesthetic care unit (PACU). There were 60 children who did not have an AE in PACU, of whom 59 did not have a severe AE in the post-operative period, giving a negative predictive value for no worse than a mild AE following an uncomplicated course in PACU of 98.3%. CONCLUSIONS: Our data confirm high rates of AE after AT for high risk patients, however, only 8% suffered a severe AE truly necessitating care in ICU. This outcome was very unlikely if an AE did not occur in PACU. We therefore conclude that routine post-operative ICU care for high risk children may be avoided if prolonged monitoring in the PACU is possible, with admission to ICU reserved for high-risk children with an early AE.

Long-term changes in neurocognition and behavior following treatment of sleep disordered breathing in school-aged children.

STUDY OBJECTIVES: Sleep disordered breathing (SDB) in children is associated with detrimental neurocognitive and behavioral consequences. The long term impact of treatment on these outcomes is unknown. This study examined the long-term effect of treatment of SDB on neurocognition, academic ability, and behavior in a cohort of school-aged children. DESIGN: Four-year longitudinal study. Children originally diagnosed with SDB and healthy non-snoring controls underwent repeat polysomnography and age-standardized neurocognitive and behavioral assessment 4y following initial testing. SETTING: Melbourne Children's Sleep Centre, Melbourne, Australia. PARTICIPANTS: Children 12-16 years of age, originally assessed at 7-12 years, were categorized into Treated (N = 12), Untreated (N = 26), and Control (N = 18) groups. INTERVENTIONS: Adenotonsillectomy, Tonsillectomy, Nasal Steroids. Decision to treat was independent of this study. MEASUREMENTS AND RESULTS: Changes in sleep and respiratory parameters over time were assessed. A decrease in obstructive apnea hypopnea index (OAHI) from Time 1 to Time 2 was seen in 63% and 100% of the Untreated and Treated groups, respectively. The predictive relationship between change in OAHI and standardized neurocognitive, academic, and behavioral scores over time was examined. Improvements in OAHI were predictive of improvements in Performance IQ, but not Verbal IQ or academic measures. Initial group differences in behavioral assessment on the Child Behavior Checklist did not change over time. Children with SDB at baseline continued to exhibit significantly poorer behavior than Controls at follow-up, irrespective of treatment. CONCLUSIONS: After four years, improvements in SDB are concomitant with improvements in some areas of neurocognition, but not academic ability or behavior in school-aged children.

Pediatric Sleep Survey Instrument--a screening tool for sleep disordered breathing.

PURPOSE: The aim of this study was to assess the construct validity and clinical application of the Pediatric Sleep Survey Instrument (PSSI) as a tool to screen for sleep disordered breathing (SDB) in children. METHODS: Polysomnography (PSG) outcomes and PSSI subscale scores were compared between a clinical cohort (N = 87, 5-10 years, 62 M/25 F) and a nonsnoring community sample (N = 55, 5-10 years, 28 M/27 F). Group comparisons assessed the ability of the PSSI subscales to discriminate between the clinical and community cohorts. Receiver operating characteristic (ROC) curves assessed construct validity, with the Apnea/Hypopnea Index (AHI) >5 events/h, OSA-18 score >60, and Pediatric Daytime Sleepiness Scale (PDSS) above the 70th percentile as the target references. RESULTS: The clinical group had more respiratory events, respiratory-related arousals, fragmented sleep, and lower oxygen saturation nadir than the community group (p < 0.001 for all). PSSI subscale scores of Morning Tiredness, Night Arousals, SDB, and Restless Sleep were higher (p < 0.001 for all) in the clinical cohort, confirming the tool's ability to identify clinically relevant sleep problems. ROC curves confirmed the diagnostic accuracy of the SDB subscale against an AHI > 5 events/h (area under the curve (AUC) = 0.7), an OSA-18 score >60 (AUC = 0.7), and a PDSS score in the 70th percentile (AUC = 0.8). The Morning Tiredness subscale accurately predicted a PDSS score in the 70th percentile (AUC = 0.8). A cutoff score of 5 on the SDB subscale showed a sensitivity of 0.94 and a specificity of 0.76, correctly identifying 77 and 100 % of the clinical and community cohorts, respectively. CONCLUSION: The PSSI Sleep Disordered Breathing subscale is a valid tool for screening SDB and daytime sleepiness in children aged 5-10 years.

Seasonal variability in paediatric obstructive sleep apnoea.

BACKGROUND: Allergy and respiratory viral infection may contribute to the pathogenesis of sleep disordered breathing (SDB) through promoting adenotonsillar growth. We investigated the seasonal variation of SDB in children by analysing the change in the obstructive apnoea hypopnoea index (OAHI) throughout the year. PARTICIPANTS: 257 3-12-year-old children referred for assessment of SDB underwent overnight polysomnography (PSG). RESULTS: Mean seasonal OAHI was significantly higher in winter (5.1±0.8 events/h) and spring (4.6±0.9 events/h) compared with autumn (2.4±0.8 events/h; p<0.01 and p<0.05, respectively) and summer (2.0±0.5 events/h; p<0.05 for both). There were no differences in OAHI between summer and the other seasons or between winter and spring. CONCLUSIONS: We identified more severe obstructive sleep apnoea in clinically referred children during winter and spring and suggest that inflammation from respiratory viruses may contribute to adenotonsillar hypertrophy, worsening airway obstruction. Clinicians should take season into account when interpreting PSG results.