Sleep-related breathing disorders in infants with spina bifida repaired prenatally and postnatally

STUDY OBJECTIVES

Advances in prenatal repair of myelomeningocele (MMC) have improved outcomes involving different organ systems. There is limited data on respiratory outcomes following prenatal surgical repair. We hypothesize there is no difference in respiratory outcomes between spina bifida (SB) patients who have undergone prenatal versus postnatal repair.

METHODS

We performed a retrospective study of 46 infants <1 year with SB seen at Children's Hospital Los Angeles from 2004-2022. Demographic data, timing of closure, neonatal course, Chiari II malformation (CIIM), ventriculoperitoneal shunt (VPS), polysomnography (PSG) results, and need for supplemental oxygen were collected. Unpaired t-test and Chi-square Test were used to analyze results.

RESULTS

31/46 had prenatal repair of MMC; average age at repair was 27 weeks post-conception (PCA). Average age at postnatal repair was 37 PCA. There was no difference in age at PSG. There was no difference in CIIM presence (p=0.61). 60% of patients with postnatal repair and 23% in the prenatal group underwent VPS placement (p=0.01).

There was no difference in PSG findings between the two groups: CAI (p=0.11), OAHI (p=0.64), average SpO2 baseline (p=0.91), average SpO2 nadir (p=0.17), average PETCO2 baseline (p=0.87), and average PETCO2 maximum (p=0.54). There were no significant differences in the proportion of patients on supplemental O2 (p=0.25), CSA or OSA between groups.

CONCLUSIONS

Patients with SB who've undergone closure of neural tube defect have persistent central apneas, obstructive apneas, and significant hypoxemia. There were no differences in the frequency or severity of sleep-disordered breathing in those with prenatal repair versus postnatal repair.

Obstructive sleep apnea as a presentation of congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome is a rare disorder due to a mutation in the PHOX2B gene, characterized by a failure in autonomic control of breathing with diminished or absent response to hypoxia and hypercapnia, which is most pronounced during sleep. Most patients present from birth with central apneas and hypoventilation, or later in the setting of a physiologic stress. Recent literature in mice with a Phox2b27Ala/+ mutation suggests a predisposition to obstructive apneas likely due to hypoglossal dysgenesis. We report on three patients with obstructive sleep apneas with absent or mild hypoventilation. Our cases propose that obstructive apneas can be the primary presentation in patients who subsequently develop the classic phenotype of congenital central hypoventilation syndrome and emphasize their close monitoring and surveillance.

CITATION

Kagan O, Zhang C, McElyea C, Keens TG, Davidson Ward SL, Perez IA. Obstructive sleep apnea as a presentation of congenital central hypoventilation syndrome. J Clin Sleep Med. 2023;19(9):1697-1700.

Prevalence of pulmonary hypertension on echocardiogram in children with severe obstructive sleep apnea

STUDY OBJECTIVES

Pulmonary hypertension (PH) is a rare yet serious complication of obstructive sleep apnea (OSA). Echocardiographic screening for PH is recommended in children with severe OSA, but the health care burden of universal screening is high. We sought to determine the prevalence of PH on echocardiogram among children with severe OSA and identify variables associated with a positive PH screen.

METHODS

Retrospective study of 318 children with severe OSA (obstructive apnea-hypopnea index ≥ 10 events/h) and echocardiogram within 1 year of polysomnogram. PH-positive echocardiogram was defined by peak tricuspid regurgitation velocity ≥ 2.5 m/s and/or 2 or more right-heart abnormalities suggestive of elevated pulmonary artery pressure. Patient characteristics and polysomnogram data were compared to identify factors associated with PH.

RESULTS

Twenty-six children (8.2%; 95% confidence interval [CI] 5.4-11.8%) had echocardiographic evidence of PH. There was no difference in age, sex, body mass index, obstructive apnea-hypopnea index, or oxygenation indices between patients with and without PH. Sleep-related hypoventilation (end-tidal CO₂ > 50 mmHg for > 25% of total sleep time) was present in 25% of children with PH compared with 6.3% of children without PH (adjusted prevalence ratio = 2.73; 95% CI 1.18-6.35). Forty-six percent of children (12/26) with PH had Down syndrome vs 14% (41/292) without PH (adjusted prevalence ratio = 3.11; 95% CI 1.46-6.65).

CONCLUSIONS

There was a relatively high prevalence of PH on echocardiogram in our cohort of children with severe OSA. The findings of increased PH prevalence among children with sleep-related hypoventilation or Down syndrome may help inform the development of targeted screening recommendations for specific pediatric OSA populations.

CITATION

Maloney MA, Davidson Ward SL, Su JA, et al. Prevalence of pulmonary hypertension on echocardiogram in children with severe obstructive sleep apnea. J Clin Sleep Med. 2022;18(6):1629-1637.

Children with Congenital Central Hypoventilation Syndrome Do Not Wake up to Ventilator Alarms

PURPOSE

Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. Subjects with CCHS are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in patients  with CCHS due to ventilatory support and other treatments at night.

METHODS

An anonymous survey of patients with CCHS, age up to 17 years was conducted through REDCAP. Subjects were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters.

RESULTS

We received 23 responses (35% female, 8.1 years ± 5.6). PHOX2B genotypes were 20/24 PARM (2), 20/25 PARM (4), 20/26 PARM (2), 20/27 PARM (9), ≥ 20/28 PARM (2), and NPARM (2). Two subjects did not indicate the PHOX2B genotype. 13/23 were ventilated by PPV via tracheostomy, 7 by NIPPV, 2 by diaphragm pacing, and 1 did not indicate. Additional treatments received at night included suctioning (9), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO₂ monitor. 17/23 rarely woke up due to ventilator or monitor alarms. 11/23 usually or sometimes woke up at least once a night; only 2/11 woke up due to alarms. 5/17 who rarely woke up to the alarms had night nursing.

CONCLUSION

Most subjects with CCHS did not awaken to ventilator or monitoring alarms and a majority of these patients did not have nighttime nursing. (Mathur et al. in Sleep 43(Supplement_1):A333, 2020).

Retrospective analysis of inpatient polysomnogram characteristics and discharge outcomes in infants with bronchopulmonary dysplasia requiring home oxygen therapy

RATIONALE

Little is known about the polysomnogram (PSG) characteristics in infants with bronchopulmonary dysplasia (BPD), especially severe BPD, who do not need home ventilatory support but are at increased risk for chronic hypoxia and are vulnerable to its effects.

OBJECTIVE

This study aims to assess PSG characteristics and change in discharge outcomes in premature infants with BPD who required oxygen therapy at discharge.

METHODS

This is a retrospective chart review of premature infants with BPD who were admitted to a quaternary newborn and infant intensive care unit from January 1, 2012 to December 31, 2015 and who underwent polysomnography before discharge.

MEASUREMENTS AND MAIN RESULTS

Data from 127 patients were analyzed. The median gestational age of our patients was 26 weeks and 1 day (interquartile range [IQR]: 24.71, 28.86). The majority of the patients had moderate-to-severe BPD. The median obstructive apnea-hypopnea index was 5.3 events/h (IQR: 2.2, 10.1). The median oxygen desaturation index was 15.7 events/h (IQR: 4.7, 35). Nadir oxygen saturation measured by pulse oximeter was 81% (IQR: 76-86) and the arousal/awakening index was 21.9 (IQR: 13.3-30.9). No statistically significant difference was noted between severe and nonsevere BPD groups for PSG characteristics. However, average end-tidal CO₂ was significantly higher in the severe BPD group (p = .0438). Infants in the severe BPD group were intubated longer than infants with nonsevere BPD (p = .0082). The corrected gestational age (CGA) at the time of discharge (CGA-PSG) and PSG (CGA-DC) was higher in severe BPD patients but not statistically different. The majority of premature infants who underwent a PSG were discharged home with oxygen, and 69% required a titration of their level of support based on results from the PSG.

CONCLUSION

Our results highlight the presence of abnormal PSG characteristics in BPD patients, as early as 43 weeks CGA. These findings have not been previously described in this patient population prior to initial discharge from the hospital. A severe BPD phenotype tends to be associated with higher respiratory morbidity compared with a nonsevere BPD phenotype for the comparable CGA. PSG, when available, may be helpful for individualizing and streamlining treatment in preparation for discharge home and mitigating the effects of intermittent hypoxic episodes.

Comparison of SIMV + PS and AC modes in chronically ventilated children and effects on speech

BACKGROUND

Two modes of ventilation commonly used in children requiring chronic home mechanical ventilation (HMV) via tracheostomy are Assist Control (AC) and Synchronized Intermittent Mandatory Ventilation with Pressure Support (SIMV + PS). There has been no study comparing these two modes of ventilation in children requiring chronic HMV.

METHODS

We studied children requiring HMV capable of completing speech testing. Study participants were blinded to changes and studied on both modes, evaluating their oxygen saturation, end-tidal carbon dioxide (PETCO2), heart rate, respiratory rate, and respiratory pattern. Subjects completed speech testing and answered subjective questions about their level of comfort, ease of breathing, and ease of speech.

RESULTS

Fifteen children aged 12.3 ± 4.8 years were tested. There was no difference in mean oxygen saturation, minimum oxygen saturation, mean PETCO2, maximum PETCO2, mean heart rate, and mean respiratory rate. The maximum heart rate on AC was significantly lower than SIMV + PS, p = .047. Subjects breathed significantly above the set rate on SIMV + PS (p = .029), though not on AC. Subjects found it significantly easier to speak on AC, though there was no statistically significant difference in speech testing. Four subjects had multiple prolonged PS breaths on SIMV + PS. Many subjects exhibited an abnormal cadence to speech, with some speaking during both inhalation and exhalation phases of breathing.

CONCLUSIONS

There were few differences between AC and SIMV + PS, with a few parameters favoring AC that may not be clinically significant. This includes the subjective perception of ease of speech. We also found unnatural patterns of speech in children requiring HMV.

Congenital Heart Disease in Patients With Cleft Lip/Palate and Its Impact on Cleft Management

Objective:

To evaluate characteristics of congenital heart disease (CHD) in patients with cleft lip and/or palate (CL/P) and assess potential associations with cleft outcomes.

Design:

Retrospective review of all patients with CL/P who underwent primary cleft treatment from 2009 to 2015.

Setting:

Children’s Hospital Los Angeles, a tertiary hospital.

Patients:

Exclusion criteria included microform cleft lip diagnosis, international patients, and patients presenting for secondary repair or revision after primary repair at another institution.

Main Outcomes Measured:

Patient demographics, prenatal and birth characteristics, CL/P characteristics, syndromic status, postoperative complications, and other outcomes were analyzed relative to CHD diagnoses and management. Patients with CL/P with (+CHD) were compared to those without (−CHD) CHD using χ2 tests and analysis of variance.

Results:

Among 575 patients with CL/P, 83 (14.4%) had CHD. Congenital heart disease rates were significantly higher in patients with cleft palate (CP) compared to other cleft types (χ2, P = .009). Eighty-one (97.6%) out of 83 +CHD patients were diagnosed prior to initial CL/P surgical assessment. Twenty-three (27.7%) +CHD patients required surgical repair of 10 cardiac anomalies prior to cleft care. Congenital heart disease was associated with delayed CP repair and increased rates of fistula in isolated patients with CP.

Conclusions:

Congenital heart disease is known to be more prevalent in patients with CL/P. These data suggest the condition is particularly increased in patients with CP. Severe forms of CHD are diagnosed and treated prior to cleft care however postoperative fistula may be more common in patients with CHD. Therefore, careful attention is required for patient optimization and palatal flap dissection in patients with coexisting CHD and CL/P.

Rapid Response and Code Events in Hospitalized Children on Home Mechanical Ventilation

BACKGROUND

There is limited knowledge of rapid-response (RR) events and code events for children receiving home mechanical ventilation (HMV) via a tracheostomy in a non-ICU respiratory care unit. The purpose of this study was to describe the demographic and clinical factors leading to deterioration among these children and to identify the incidence and outcomes following rapid-response and code events.

METHODS

A retrospective review was conducted on hospitalized HMV children who had RR/code events in a non-ICU respiratory care unit.

RESULTS

There were a total of 50 RR events, and the primary clinical problem was acute respiratory distress, with 27 subjects (54%) needing ventilator adjustments. Twenty (40%) RR events occurred among children who were awaiting initial home discharge. Of 18 total code events, 7 (39%) children needed a tracheostomy-related intervention. There were 10 (56%) codes among children on mechanical ventilation awaiting initial home discharge. Children on HMV had 8.73 RR events per 1,000 patient days, whereas all other hospitalized children had 4.61 RR events per 1,000 patient days. In addition, children on HMV had 3.14 codes per 1,000 patient days, whereas all other hospitalized children had 0.74 codes per 1,000 patient days. All children were discharged from the hospital, and no deaths were associated with RR/code events for the index hospitalization.

CONCLUSIONS

The overall incidence of RR/code events in children on HMV was higher than among non-HMV hospitalized children. Children on HMV preparing for their initial hospital discharge had the greatest number of RR/code events. The most prevalent interventions among children with RR events were ventilator setting adjustments, and among children with codes the most frequent actions were tracheostomy-related interventions. Developing strategies to predict risk factors for RR/code events may help decrease harm among children on HMV.

Evaluation of Obstructive Sleep Apnea in Prone Versus Nonprone Body Positioning With Polysomnography in Infants With Robin Sequence

Objective:

Management of obstructive sleep apnea in infants with Robin sequence (RS) includes prone positioning during sleep, which conflicts with safe infant sleep data. We examined changes in polysomnography (PSG) parameters for prone versus nonprone body positions in these infants.

Design:

Pre–post interventional, nonblinded study.

Participants:

Infants with RS referred for PSG were recruited from craniofacial clinic and inpatient units at Children’s Hospital Los Angeles, a tertiary pediatric center. Fourteen infants were recruited, and 12 studies were completed on both body positions; 11 studies were used in the analysis.

Interventions:

The PSG was divided into nonprone and prone sleep, moving from their usual sleep position to the other position midway in the study.

Main Outcome Measures:

Data was collected in each position for obstructive apnea–hypopnea index (oAHI), central apnea index (CAI), sleep efficiency (SE), and arousal index (AI). Signed rank test was used to evaluate the change in body position.

Results:

All infants were term except 1, age 7 to 218 days (mean: 55 days; standard deviation: 58 days), and 8 (57%) of 14 were female. From nonprone to prone sleep position, the median oAHI (16.0-14.0), CAI (2.9-1.0), and AI (28.0-19.9) decreased ( P = .065); SE increased (67.4-85.2; P = .227).

Conclusions:

Prone positioning may benefit some infants with RS. However, even those with significant improvement in obstructive sleep apnea did not completely resolve their obstruction. The decision to use prone positioning as a therapy should be objectively evaluated in individual infants.

Association between REM sleep and obstructive sleep apnea in obese and overweight adolescents

PURPOSE

Overweight and obese children have demonstrated reduced rapid eye movement (REM) sleep, affecting energy balance regulation and predisposition to weight gain. Obstructive sleep apnea (OSA) is a known cause of decreased REM sleep. The purpose of this study is to examine the association between the percentage of REM sleep, BMI z-score, and OSA severity in overweight and obese adolescents.

METHODS

We performed a cross-sectional study of 92 (43% female) overweight and obese adolescents (13-17 years old) who underwent overnight polysomnography (PSG) at Children's Hospital Los Angeles between 2010 and 2017.

RESULTS

The average Body Mass Index (BMI) z-score was 2.27 ± 0.47, with 71% having BMI z-score ≥ 2. REM% during PSG was 15.6 ± 6.8, and obstructive apnea-hypopnea index was 17.1 ± 24.3. The distribution across categories of OSA severity was 27% none (≤ 1.5 events/h), 24% mild (> 1.5-5 events/h), 8% moderate (> 5-10 events/h), and 41% severe (> 10 events/h). REM% was not associated with BMI z-score, either on univariate or multivariate regression with adjustment for age, gender, and apnea-hypopnea index (AHI). When subdivided into OSA categories, a 1-unit increase in BMI z-score was associated with a 5.96 (p = 0.03) increase in REM% in mild OSA and an 8.86 (p = 0.02) decrease in REM% in severe OSA. There was no association between BMI z-score and REM% in none and moderate OSA.

CONCLUSION

Among overweight and obese adolescents, BMI z-score was associated with decreased REM% in severe OSA and unexpectedly increased REM% in mild OSA, but there was no association in none or moderate OSA.

Case Report of Pediatric Channelopathies With UNC80 and KCNJ11 Mutations Having Abnormal Respiratory Control Treated With Positive Airway Pressure Therapy

ABSTRACT

There have been no published reports of central respiratory control abnormalities in pediatric patients with UNC80 or KCNJ11 mutations which cause neurologic channelopathies. We describe an 8-year-old male with a pathogenic UNC80 mutation, intellectual disability, hypotonia and epilepsy with severe central sleep apnea (213.5 events/h) on polysomnography (PSG). We also describe a 20-month-old female with a KCNJ11 mutation, neonatal diabetes and developmental delay who had severe central sleep apnea (131.1 events/h). Both patients had irregular respiratory patterns during sleep and wakefulness and were placed on empiric bilevel positive airway pressure therapy, which was well tolerated with resolution of abnormal respiratory control and hypercapnia. Patients with UNC80 and KCNJ11 gene mutations may have abnormal respiratory rhythm during sleep and wakefulness, mirroring animal models. We recommend routine PSG tests and further investigation into the respiratory control of patients with pediatric channelopathies involved in chemoreceptor function or central integration of respiratory control.

Obstructive Sleep Apnea in Patients With Congenital Central Hypoventilation Syndrome Ventilated by Diaphragm Pacing Without Tracheostomy

STUDY OBJECTIVES

To determine presence of obstructive sleep apnea (OSA) in patients with congenital central hypoventilation syndrome (CCHS) ventilated by diaphragm pacing (DP) without tracheostomy, and to determine if OSA can be improved by DP setting changes.

METHODS

We reviewed polysomnography (PSG) results of 15 patients with CCHS from October 2001 to April 2014, age 15.4 ± 7.8 years, body mass index 22.0 ± 6.0 kg/m², and 60% female.

RESULTS

Of the 22 PSG results obtained for the 15 patients with CCHS, 9 were performed with tracheostomy capped, and 13 were performed after patients underwent decannulation. OSA was present on 6 of 9 tests in patients with tracheostomy capped, including 3 patients with immediate, severe OSA necessitating that the studies be completed with tracheostomy uncapped. OSA was present on 2 of 13 tests in patients in whom decannulation had been performed. Hypoventilation was seen on only one test without OSA. On 2 of 5 tests showing OSA, OSA improved by decreasing DP amplitude settings; apnea-hypopnea index decreased from 11.1 ± 2.5 to 1.8 ± 2.5 events/h; PETCO₂ decreased from 57.5 ± 3.5 to 38.5 ± 0.7 torr; SpO₂ increased from 76.5 ± 0.7% to 93.0 ± 7.1%. OSA improved in one patient with slight increase in respiratory rate. Settings were manipulated in 4 tests showing OSA; no changes were attempted in the remaining study. One patient was placed on bilevel positive airway pressure with temporary suspension of DP. Age (P < .119), previous adenotonsillectomy (P < .211), and body mass index (P < .112) did not significantly contribute to OSA.

CONCLUSIONS

OSA occurs in patients with CCHS ventilated by DP. However, decreasing DP amplitude settings can lessen upper airway obstruction without compromising gas exchange.

Pharyngeal Flap and Sphincterplasty for Velopharyngeal Insufficiency Have Equal Outcome at 1 Year Postoperatively: Results of a Randomized Trial

Objective

The aim of this trial was to compare the relative effectiveness (efficacy and morbidity) of two surgical procedures for correcting velopharyngeal insufficiency (VPI).

Design

This was an international multicenter randomized trial to study the outcome of two surgical procedures (flap and sphincter pharyngoplasty) for speech, incidence of sleep apnea, and surgical complications.

Method

Ninety-seven patients 3 to 25 years old with repaired cleft palate and previously identified VPI were enrolled from five centers in the United States, Norway, and the U.K. Data were collected at presurgery, 3 months postsurgery, and 12 months postsurgery for subsequent analysis blind to the procedure. Main outcome measures included perceptual speech parameters, sleep apnea, nasalance measures, endoscopic features, and surgical complications.

Results

Groups for both surgical procedures achieved a high level of clinical improvement. At 3 months postsurgery, elimination of hypernasal resonance was achieved in twice as many patients after the flap procedure. This reached significance. However, at 12 months postsurgery, no statistically significant difference in outcomes remained between the two procedures for resonance, nasalance, endoscopic outcomes, or surgical complications. Flap and sphincter pharyngoplasty rarely resulted in clinically significant sleep apnea, and no difference was detected between the two procedures in the long-term incidence of sleep apnea.

Conclusions

Despite strongly held views in the literature concerning the relative effectiveness and safety of flap and sphincter pharyngoplasty, no significant differences were detected 1 year postoperatively.

Real-time multislice MRI during continuous positive airway pressure reveals upper airway response to pressure change

PURPOSE

To determine if a real-time magnetic resonance imaging (RT-MRI) method during continuous positive airway pressure (CPAP) can be used to measure neuromuscular reflex and/or passive collapsibility of the upper airway in individual obstructive sleep apnea (OSA) subjects.

MATERIALS AND METHODS

We conducted experiments on four adolescents with OSA and three healthy controls, during natural sleep and during wakefulness. Data were acquired on a clinical 3T scanner using simultaneous multislice (SMS) RT-MRI during CPAP. CPAP pressure level was alternated between therapeutic and subtherapeutic levels. Segmented airway area changes in response to rapid CPAP pressure drop and restoration were used to estimate 1) upper airway loop gain (UALG), and 2) anatomical risk factors, including fluctuation of airway area (FAA).

RESULTS

FAA significantly differed between OSA patients (2-4× larger) and healthy controls (Student's t-test, P < 0.05). UALG and FAA measurements indicate that neuromuscular reflex and passive collapsibility varied among the OSA patients, suggesting the presence of different OSA phenotypes. Measurements had high intrasubject reproducibility (intraclass correlation coefficient r > 0.7).

CONCLUSION

SMS RT-MRI during CPAP can reproducibly identify physiological traits and anatomical risk factors that are valuable in the assessment of OSA. This technique can potentially locate the most collapsible airway sites. Both UALG and FAA possess large variation among OSA patients.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1400-1408.

Evaluation of upper airway collapsibility using real-time MRI

PURPOSE

To develop and demonstrate a real-time MRI method for assessing upper airway collapsibility in sleep apnea.

MATERIALS AND METHODS

Data were acquired on a clinical 3 Tesla scanner using a radial CAIPIRIHNA sequence with modified golden angle view ordering and reconstructed using parallel imaging and compressed sensing with temporal finite difference sparsity constraint. Segmented airway areas together with synchronized facemask pressure were used to calculate airway compliance and projected closing pressure, Pclose , at four axial locations along the upper airway. This technique was demonstrated in five adolescent obstructive sleep apnea (OSA) patients, three adult OSA patients and four healthy volunteers. Heart rate, oxygen saturation, facemask pressure, and abdominal/chest movements were monitored in real-time during the experiments to determine sleep/wakefulness.

RESULTS

Student's t-tests showed that both compliance and Pclose were significantly different between healthy controls and OSA patients (P < 0.001). The results also suggested that a narrower airway site does not always correspond to higher collapsibility.

CONCLUSION

With the proposed methods, both compliance and Pclose can be calculated and used to quantify airway collapsibility in OSA with an awake scan of 30 min total scan room time. J. Magn. Reson. Imaging 2016;44:158-167.

Body Fat Composition: A Predictive Factor for Sleep Related Breathing Disorder in Obese Children

INTRODUCTION

The association between body fat composition as measured by dual energy x-ray absorptiometry (DEXA) scanning and pediatric sleep related breathing disorder (SRBD) is not well established. We investigated the relationship between body mass index (BMI) and DEXA parameters and their association with SRBD in obese children.

PATIENTS AND METHODS

Overnight polysomnography was performed on obese/overweight children (10-17 years) with habitual snoring. Total body fat mass (g), trunk fat mass (g), total body % fat, and trunk % fat were determined by DEXA.

RESULTS

Forty-one subjects were studied. Logarithm (Log) total arousal index correlated with BMI (p < 0.01, r = 0.473), total body fat mass (p < 0.05, r = 0.331), and trunk fat mass (p < 0.05, r = 0.319). Log desaturation index correlated with BMI (p < 0.05, r = 0.313), total body fat mass (p < 0.05, r = 0.375), and trunk fat mass (p < 0.05, r = 0.391), whereas obstructive apnea hypopnea index (OAHI) did not. In males 10-12 years, there was a significant correlation between Log total arousal index and obesity parameters, but not for males aged 13-17 years. BMI correlated with DEXA parameters in all subjects: total body fat mass (p < 0.001, r = 0.850); total body % fat (p < 0.01, r = 0.425); trunk fat mass (p < 0.001, r = 0.792) and trunk % fat (p < 0.05, r = 0.318) and in 10-12 year old males. This relationship was not significant in males aged 13-17 years.

CONCLUSIONS

Total body fat mass and trunk fat mass as well as BMI correlated with total arousal index and desaturation index. BMI correlated with DEXA parameters in 10-12 year old males but not in 13-17 year old males. The value of using DEXA scanning to study the relationship between obesity and SRBD may depend on age and pubertal stage.

Dynamic 3-D MR Visualization and Detection of Upper Airway Obstruction During Sleep Using Region-Growing Segmentation

GOAL

We demonstrate a novel and robust approach for visualization of upper airway dynamics and detection of obstructive events from dynamic 3-D magnetic resonance imaging (MRI) scans of the pharyngeal airway.

METHODS

This approach uses 3-D region growing, where the operator selects a region of interest that includes the pharyngeal airway, places two seeds in the patent airway, and determines a threshold for the first frame.

RESULTS

This approach required 5 s/frame of CPU time compared to 10 min/frame of operator time for manual segmentation. It compared well with manual segmentation, resulting in Dice Coefficients of 0.84 to 0.94, whereas the Dice Coefficients for two manual segmentations by the same observer were 0.89 to 0.97. It was also able to automatically detect 83% of collapse events.

CONCLUSION

Use of this simple semiautomated segmentation approach improves the workflow of novel dynamic MRI studies of the pharyngeal airway and enables visualization and detection of obstructive events.

SIGNIFICANCE

Obstructive sleep apnea (OSA) is a significant public health issue affecting 4-9% of adults and 2% of children. Recently, 3-D dynamic MRI of the upper airway has been demonstrated during natural sleep, with sufficient spatiotemporal resolution to noninvasively study patterns of airway obstruction in young adults with OSA. This study makes it practical to analyze these long scans and visualize important factors in an MRI sleep study, such as the time, site, and extent of airway collapse.

Pediatric sleep-related breathing disorders: advances in imaging and computational modeling

We understand now that sleep of sufficient length and quality is required for good health. This is particularly true for infants and children, who have the added physiologic task of growth and development, as compared to their adult counterparts. Sleep-related breathing disorders (SRBDs) are common in childhood and if unrecognized and not treated can result in significant morbidity. For example, children with obstructive sleep apnea (OSA) can exhibit behavioral, mood, and learning difficulties. If left untreated, alterations in the function of the autonomic nervous system and a chronic inflammatory state result, contributing to the risk of heart disease, stroke, glucose intolerance, and hypertension in adulthood.

Syncope at altitude: an enigmatic case

We report a case of a young boy with recurrent episodes of syncope at elevated altitude. While not conforming to common presentations of altitude sickness, the differential diagnoses and possible etiologies are discussed.

Vallecular cyst as a cause of obstructive sleep apnea in an infant

A 3-month-old baby was diagnosed with obstructive sleep apnea (OSA) on polysomnography (PSG) with a high apnea hypopnea index (AHI). On further investigations he was found to have a vallecular cyst that was successfully treated. We discuss the clinical presentation of vallecular cysts and the importance of polysomnography in identifying this rare condition.

Real-time 3D magnetic resonance imaging of the pharyngeal airway in sleep apnea

PURPOSE

To investigate the feasibility of real-time 3D magnetic resonance imaging (MRI) with simultaneous recording of physiological signals for identifying sites of airway obstruction during natural sleep in pediatric patients with sleep-disordered breathing.

METHODS

Experiments were performed using a three-dimensional Fourier transformation (3DFT) gradient echo sequence with prospective undersampling based on golden-angle radial spokes, and L1-norm regularized iterative self-consistent parallel imaging (L1-SPIRiT) reconstruction. This technique was demonstrated in three healthy adult volunteers and five pediatric patients with sleep-disordered breathing. External airway occlusion was used to induce partial collapse of the upper airway on inspiration and test the effectiveness of the proposed imaging method. Apneic events were identified using information available from synchronized recording of mask pressure and respiratory effort.

RESULTS

Acceptable image quality was obtained in seven of eight subjects. Temporary airway collapse induced via inspiratory loading was successfully imaged in all three volunteers, with average airway volume reductions of 63.3%, 52.5%, and 33.7%. Central apneic events and associated airway narrowing/closure were identified in two pediatric patients. During central apneic events, airway obstruction was observed in the retropalatal region in one pediatric patient.

CONCLUSION

Real-time 3D MRI of the pharyngeal airway with synchronized recording of physiological signals is feasible and may provide valuable information about the sites and nature of airway narrowing/collapse during natural sleep.

Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine

The American Academy of Sleep Medicine (AASM) Sleep Apnea Definitions Task Force reviewed the current rules for scoring respiratory events in the 2007 AASM Manual for the Scoring and Sleep and Associated Events to determine if revision was indicated. The goals of the task force were (1) to clarify and simplify the current scoring rules, (2) to review evidence for new monitoring technologies relevant to the scoring rules, and (3) to strive for greater concordance between adult and pediatric rules. The task force reviewed the evidence cited by the AASM systematic review of the reliability and validity of scoring respiratory events published in 2007 and relevant studies that have appeared in the literature since that publication. Given the limitations of the published evidence, a consensus process was used to formulate the majority of the task force recommendations concerning revisions.The task force made recommendations concerning recommended and alternative sensors for the detection of apnea and hypopnea to be used during diagnostic and positive airway pressure (PAP) titration polysomnography. An alternative sensor is used if the recommended sensor fails or the signal is inaccurate. The PAP device flow signal is the recommended sensor for the detection of apnea, hypopnea, and respiratory effort related arousals (RERAs) during PAP titration studies. Appropriate filter settings for recording (display) of the nasal pressure signal to facilitate visualization of inspiratory flattening are also specified. The respiratory inductance plethysmography (RIP) signals to be used as alternative sensors for apnea and hypopnea detection are specified. The task force reached consensus on use of the same sensors for adult and pediatric patients except for the following: (1) the end-tidal PCO(2) signal can be used as an alternative sensor for apnea detection in children only, and (2) polyvinylidene fluoride (PVDF) belts can be used to monitor respiratory effort (thoracoabdominal belts) and as an alternative sensor for detection of apnea and hypopnea (PVDFsum) only in adults.The task force recommends the following changes to the 2007 respiratory scoring rules. Apnea in adults is scored when there is a drop in the peak signal excursion by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative apnea sensor, for ≥ 10 seconds. Hypopnea in adults is scored when the peak signal excursions drop by ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ 10 seconds in association with either ≥ 3% arterial oxygen desaturation or an arousal. Scoring a hypopnea as either obstructive or central is now listed as optional, and the recommended scoring rules are presented. In children an apnea is scored when peak signal excursions drop by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative sensor; and the event meets duration and respiratory effort criteria for an obstructive, mixed, or central apnea. A central apnea is scored in children when the event meets criteria for an apnea, there is an absence of inspiratory effort throughout the event, and at least one of the following is met: (1) the event is ≥ 20 seconds in duration, (2) the event is associated with an arousal or ≥ 3% oxygen desaturation, (3) (infants under 1 year of age only) the event is associated with a decrease in heart rate to less than 50 beats per minute for at least 5 seconds or less than 60 beats per minute for 15 seconds. A hypopnea is scored in children when the peak signal excursions drop is ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ the duration of 2 breaths in association with either ≥ 3% oxygen desaturation or an arousal. In children and adults, surrogates of the arterial PCO(2) are the end-tidal PCO(2) or transcutaneous PCO(2) (diagnostic study) or transcutaneous PCO(2) (titration study). For adults, sleep hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 55 mm Hg for ≥ 10 minutes or there is an increase in the arterial PCO(2) (or surrogate) ≥ 10 mm Hg (in comparison to an awake supine value) to a value exceeding 50 mm Hg for ≥ 10 minutes. For pediatric patients hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 50 mm Hg for > 25% of total sleep time. In adults Cheyne-Stokes breathing is scored when both of the following are met: (1) there are episodes of ≥ 3 consecutive central apneas and/or central hypopneas separated by a crescendo and decrescendo change in breathing amplitude with a cycle length of at least 40 seconds (typically 45 to 90 seconds), and (2) there are five or more central apneas and/or central hypopneas per hour associated with the crescendo/decrescendo breathing pattern recorded over a minimum of 2 hours of monitoring.

Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine

The American Academy of Sleep Medicine (AASM) Sleep Apnea Definitions Task Force reviewed the current rules for scoring respiratory events in the 2007 AASM Manual for the Scoring and Sleep and Associated Events to determine if revision was indicated. The goals of the task force were (1) to clarify and simplify the current scoring rules, (2) to review evidence for new monitoring technologies relevant to the scoring rules, and (3) to strive for greater concordance between adult and pediatric rules. The task force reviewed the evidence cited by the AASM systematic review of the reliability and validity of scoring respiratory events published in 2007 and relevant studies that have appeared in the literature since that publication. Given the limitations of the published evidence, a consensus process was used to formulate the majority of the task force recommendations concerning revisions.The task force made recommendations concerning recommended and alternative sensors for the detection of apnea and hypopnea to be used during diagnostic and positive airway pressure (PAP) titration polysomnography. An alternative sensor is used if the recommended sensor fails or the signal is inaccurate. The PAP device flow signal is the recommended sensor for the detection of apnea, hypopnea, and respiratory effort related arousals (RERAs) during PAP titration studies. Appropriate filter settings for recording (display) of the nasal pressure signal to facilitate visualization of inspiratory flattening are also specified. The respiratory inductance plethysmography (RIP) signals to be used as alternative sensors for apnea and hypopnea detection are specified. The task force reached consensus on use of the same sensors for adult and pediatric patients except for the following: (1) the end-tidal PCO(2) signal can be used as an alternative sensor for apnea detection in children only, and (2) polyvinylidene fluoride (PVDF) belts can be used to monitor respiratory effort (thoracoabdominal belts) and as an alternative sensor for detection of apnea and hypopnea (PVDFsum) only in adults.The task force recommends the following changes to the 2007 respiratory scoring rules. Apnea in adults is scored when there is a drop in the peak signal excursion by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative apnea sensor, for ≥ 10 seconds. Hypopnea in adults is scored when the peak signal excursions drop by ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ 10 seconds in association with either ≥ 3% arterial oxygen desaturation or an arousal. Scoring a hypopnea as either obstructive or central is now listed as optional, and the recommended scoring rules are presented. In children an apnea is scored when peak signal excursions drop by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative sensor; and the event meets duration and respiratory effort criteria for an obstructive, mixed, or central apnea. A central apnea is scored in children when the event meets criteria for an apnea, there is an absence of inspiratory effort throughout the event, and at least one of the following is met: (1) the event is ≥ 20 seconds in duration, (2) the event is associated with an arousal or ≥ 3% oxygen desaturation, (3) (infants under 1 year of age only) the event is associated with a decrease in heart rate to less than 50 beats per minute for at least 5 seconds or less than 60 beats per minute for 15 seconds. A hypopnea is scored in children when the peak signal excursions drop is ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ the duration of 2 breaths in association with either ≥ 3% oxygen desaturation or an arousal. In children and adults, surrogates of the arterial PCO(2) are the end-tidal PCO(2) or transcutaneous PCO(2) (diagnostic study) or transcutaneous PCO(2) (titration study). For adults, sleep hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 55 mm Hg for ≥ 10 minutes or there is an increase in the arterial PCO(2) (or surrogate) ≥ 10 mm Hg (in comparison to an awake supine value) to a value exceeding 50 mm Hg for ≥ 10 minutes. For pediatric patients hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 50 mm Hg for > 25% of total sleep time. In adults Cheyne-Stokes breathing is scored when both of the following are met: (1) there are episodes of ≥ 3 consecutive central apneas and/or central hypopneas separated by a crescendo and decrescendo change in breathing amplitude with a cycle length of at least 40 seconds (typically 45 to 90 seconds), and (2) there are five or more central apneas and/or central hypopneas per hour associated with the crescendo/decrescendo breathing pattern recorded over a minimum of 2 hours of monitoring.

Sleep fragmentation and intermittent hypoxemia are associated with decreased insulin sensitivity in obese adolescent Latino males

BACKGROUND

Although sleep-related breathing disorder (SRBD) has been linked to insulin resistance in adults, this has not been as well established in children. We hypothesized that the severity of SRBD in adolescents was associated with metabolic impairment.

METHODS

Polysomnography was performed on obese, Latino males referred for snoring. The frequently sampled intravenous glucose tolerance test was used to assess glucose homeostasis. Total-body dual-energy X-ray absorptiometry was used to quantify adiposity.

RESULTS

A total of 22 males (mean age ± SD: 13.4 ± 2.1 y, BMI z-score 2.4 ± 0.3, obstructive apnea hypopnea index 4.1 ± 3.2) were studied. After correcting for age and adiposity in multiple-regression models, Log frequency of desaturation (defined as ≥3% drop in oxygen saturation from baseline) negatively correlated with insulin sensitivity. Sleep efficiency was positively correlated with glucose effectiveness (S(G), the capacity of glucose to mediate its own disposal). The Log total arousal index was positively correlated with Log homeostasis model assessment-estimated insulin resistance.

CONCLUSION

Sleep fragmentation and intermittent hypoxemia are associated with metabolic impairment in obese adolescent Latino males independent of age and adiposity. We speculate that SRBD potentiates the risk for development of metabolic syndrome and type 2 diabetes in the obese adolescent population.

Effect of residential proximity to major roadways on cystic fibrosis exacerbations

Ambient air pollution has been attributed with an increase in exacerbation frequencies among the cystic fibrosis (CF) population. This study correlates exacerbation frequency with proximity to roadways and two criteria air pollutants. Clinical data was extracted from the Cystic Fibrosis Foundation National Patient Registry and Electronic Medical Records at Children's Hospital Los Angeles (CHLA). Average annual air pollutant levels were obtained from selected US Environmental Protection Agency's monitoring stations. Geographic proximity to monitoring stations and roadways were analyzed using spatial mapping software. A total of 145 patients from the CHLA's CF center were characterized by a dichotomous exacerbation category. No significant association was determined between the frequency of exacerbations and exposure to fine particulate matter and ozone levels. Residential proximity to US-designated highways and freeways also did not achieve significance (p = 0.3777) but was noted to be correlated with major arterial roadways (p = 0.0420). Associations of environmental exposures may have important implications for future predictive models of CF clinical outcomes.

Development and growth of a large multispecialty certification examination: sleep medicine certification--results of the first three examinations

This paper summarizes the results of the first three examinations (2007, 2009, and 2011) of the Sleep Medicine Certification Examination, administered by its six sponsoring American Board of Medical Specialty Boards. There were 2,913 candidates who took the 2011 examination through one of three pathways-self-attested practice experience, previous certification by the American Board of Sleep Medicine, or formal Sleep Medicine fellowship training. The 2011 exam was the last administration in which candidates who had not previously been admitted could take it without completion of formal Sleep Medicine fellowship training. As expected, the number of candidates admitted to the 2011 examination through the practice experience pathway increased, and the overall scores of these candidates were on average lower than the other candidates. Consequently, the pass rate for all first takers of the 2011 examination (65%) was lower than that observed from the 2009 examination (78%) and the 2007 examination (73%). For each administration, candidates admitted through the fellowship training pathway scored the highest; over 90% of them passed the 2011 and 2009 examinations.

Hospital readmissions for newly discharged pediatric home mechanical ventilation patients

BACKGROUND

Ventilator-dependent children have complex chronic conditions that put them at risk for acute illness and repeated hospitalizations.

OBJECTIVES

To determine the 12-month incidence of and risk factors for non-elective readmission in children with chronic respiratory failure (CRF) after initiation on home mechanical ventilation (HMV) via tracheostomy.

METHODS

A retrospective cohort study of 109 HMV patients initiated and followed at an university-affiliated children's hospital between 2003 and 2009. Patient characteristics are presented using descriptive statistics; generalized estimated equations are used to estimate adjusted odds ratios of select predictor variables for readmission.

RESULTS

The 12-month incidence of non-elective readmission was 40%. Close to half of these readmissions occurred within the first 3 months post-index discharge. Pneumonia and tracheitis were the most common reasons for readmission; 64% were pulmonary- or tracheostomy-related. Most demographic and clinical patient characteristics were not statistically associated with non-elective readmissions. Although, a change in the child's management within 7 days before discharge was associated readmissions shortly after index discharge.

CONCLUSION

Non-elective readmissions of newly initiated pediatric HMV patients were common and likely multifactorial. Many of these readmissions were airway-related, and some may have been potentially preventable.

Neonatal and Infant Mandibular Distraction as an Alternative to Tracheostomy in Severe Obstructive Sleep Apnea

Context

Surgical management for severe obstructive sleep apnea has been tracheostomy, which has significant morbidity.

Objective

To determine the efficacy of internal mandibular distraction in treating severe obstructive sleep apnea in infants and neonates.

Design

Retrospective review of medical records of 29 patients who underwent internal mandibular distraction for obstructive sleep apnea secondary to micrognathia.

Setting

Nonprofit, academic, pediatric medical center.

Patients

A total of 29 infants with obstructive sleep apnea were studied. Nine were included in the respiratory failure group requiring intubation prior to distraction surgery. The other 20 were included in the respiratory distress group and underwent preoperative polysomnography that assessed the severity of obstructive sleep apnea as measured by the apnea-hypopnea index. One patient expired following surgery; the remaining 28 underwent postoperative polysomnography determining their postoperative apnea-hypopnea index.

Interventions

Bilateral mandibular distraction with internal microdistractors.

Main Outcome Measure

Improvement in the apnea-hypopnea index or extubation.

Results

The nine respiratory failure patients avoided tracheostomy and were successfully extubated postdistraction. Eight in this group had postoperative polysomnographies showing a mean apnea-hypopnea index of 3.13 (range, 0 to 13.9). All 20 patients in the respiratory distress group underwent polysomnography and showed improved apnea-hypopnea indices ( p < .001). The mean pre-op apnea-hypopnea index was 39.7 (range, 4.5 to 177), and the mean post-op apnea-hypopnea index was 5.8 (range, 0 to 34). Average improvement in the apnea-hypopnea index was 33.9. The mean follow-up period was 18.7 months (1.6 to 45.2 months).

Conclusions

Infants with micrognathia and obstructive sleep apnea may avoid tracheostomy and its inherent risks and complications by undergoing internal mandibular distraction, which is a viable alternative to tracheostomy.

Longitudinal assessment of hemoglobin oxygen saturation in preterm and term infants in the first six months of life

OBJECTIVE

To report longitudinal home recordings of hemoglobin O(2) saturation by pulse oximetry (Spo(2)) during unperturbed sleep in preterm and term infants.

STUDY DESIGN

We recorded continuous pulse oximetry during the first 3 minutes of each hour of monitor use (nonevent epochs) for 103 preterm infants born at <1750 g and ≤ 34 weeks postmenstrual age (PMA), and 99 healthy term infants.

RESULTS

Median baseline Spo(2) was approximately 98% for both the preterm and term groups. Episodes of intermittent hypoxemia occurred in 74% of preterm and 62% of term infants. Among infants with intermittent hypoxemia, the number of seconds/hour of monitoring <90% Spo(2) was initially significantly greater in the preterm than the term group and declined with age at a similar rate in both groups. The 75(th) to 95(th) percentiles for seconds/hour of Spo(2) <90% in preterm infants were highest at 36 weeks PMA and progressively decreased until 44 weeks PMA, after which time they did not differ from term infants.

CONCLUSIONS

Clinically inapparent intermittent hypoxemia occurs in epochs unperturbed by and temporally unrelated to apnea or bradycardia events, especially in preterm infants at 36 to 44 weeks PMA.

Development and results of the first ABMS subspecialty Certification Examination in Sleep Medicine

In November 2007, the first Certification Examination in Sleep Medicine was administered to 1,882 candidates under the cosponsorship of five member boards of the American Board of Medical Specialties (ABMS)--the American Board of Internal Medicine, the American Board of Family Medicine, the American Board of Otolaryngology, the American Board of Pediatrics, and the American Board of Psychiatry and Neurology. The pass rate was 73%. This paper chronicles the history of a certification examination in Sleep Medicine and the development of this new ABMS examination.

The snoring child

Snoring is a common manifestation of obstructive sleep apnea and represents one end of the spectrum of sleep-related breathing disorders. Children with primary snoring initially may develop OSAS later, so inquiring about symptoms of OSAS should be part of each visit. Obstructive sleep apnea can result in serious cardiovascular and metabolic consequences and neurocognitive deficits. Adenotonsillar hypertrophy remains the most common cause of OSA although the rising prevalence of obesity is of increasing importance. Polysomnography remains the gold standard in the diagnoses of OSAS and in assessing the risks associated with surgery. Most children with OSAS can be treated with adenotonsillectomy in the ambulatory surgery center. However, there are children at risk for severe OSAS and for postoperative complications, who will need PICU care. In addition to adenotonsillectomy, OSAS can be treated successfully in referral centers with other surgical approaches and by the use of positive airway pressure. Children with obesity-related OSAS often require CPAP or BPAP for control of OSAS.

Precursors of cardiorespiratory events in infants detected by home memory monitor

In 1,079 infants monitored for >700,000 hr at home for apnea or bradycardia, we found an association between infants having multiple events exceeding conventional or a priori defined more extreme thresholds and less favorable developmental outcome at 1 year of age than infants with few or no events. If it is necessary to prevent such events to minimize risk for developmental morbidity, there is reason to determine whether there are disturbances in advance of the apnea or bradycardia that herald their onset. In the 85 infants with at least 1 extreme event and 1 conventional event, we hypothesized that apnea and bradycardia do not occur de novo but rather are preceded by cardiorespiratory and hemoglobin O2 saturation changes. We compared recorded time intervals preceding these events, and we analyzed three preceding time intervals for each conventional and extreme event, and each non-event recording: Time-2 hr: up to 2 hr before; Time-1 hr: up to 1 hr before; and Time-75 sec: the 75 sec immediately preceding each event. O2 saturation progressively decreased preceding both conventional and extreme events, and progressive increases occurred in heart and breathing rate variability. Duration of respiratory pauses and of periodic breathing progressively increased preceding conventional events, respiratory rate variability increased immediately preceding conventional events and at 1 hr preceding extreme events, and O2 saturation decreased immediately preceding both conventional and extreme events. Thus, conventional and extreme events do not occur de novo but rather are preceded by autonomic instability of the cardiorespiratory system.

Noninvasive assessment of cardiovascular autonomic control in congenital central hypoventilation syndrome

The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular and respiratory response abnormalities, in patients with congenital central hypoventilation syndrome (CCHS). During wakefulness, we continuously measured the ECG, arterial blood pressure (ABP), airflow, end-tidal CO2 partial pressure (PETCO2), and arterial oxygen saturation (SatO2) in each subject. These measurements were made during spontaneous breathing in supine, sitting and standing postures, and also when each subject tracked his/her prior spontaneous breathing pattern while supine. We also performed the cold face test, hyperoxic hypercapnic rebreathing and the isocapnic hypoxic rebreathing challenges. Using spectral analysis and modeling techniques, we sought to computationally delineate the physiological mechanisms that mediate these abnormalities, as well as to determine the extent to which these abnormalities are related to peripheral or central chemoreflex dysfunction. Our preliminary results support the notion that sympathetic tone is markedly elevated in CCHS, and that differences in autonomic control from normal controls can be delineated by observing the responses to different stressors.

Adherence to and effectiveness of positive airway pressure therapy in children with obstructive sleep apnea

OBJECTIVES

Positive airway pressure therapy (PAP) is frequently used to treat children who have obstructive sleep apnea syndrome and do not respond to adenotonsillectomy. However, no studies have evaluated objectively adherence to PAP in children, and few studies have evaluated objectively the effectiveness of PAP. The objective of this study was to determine adherence and effectiveness of PAP (both continuous [CPAP] and bilevel [BPAP] pressure) in children with obstructive apnea.

METHODS

A prospective, multicenter study was performed of children who were randomly assigned in a double-blind manner to 6 months of CPAP versus BPAP. Adherence was measured objectively using the equipment's computerized output. Effectiveness was evaluated using polysomnography.

RESULTS

Twenty-nine children were studied. Approximately one third of children dropped out before 6 months. Of the 21 children for whom 6-month adherence data could be downloaded, the mean nightly use was 5.3 +/- 2.5 (SD) hours. Parental assessment of PAP use considerably overestimated actual use. PAP was highly effective, with a reduction in the apnea hypopnea index from 27 +/- 32 to 3 +/- 5/hour, and an improvement in arterial oxygen saturation nadir from 77 +/- 17% to 89 +/- 6%. Results were similar for children who received CPAP versus BPAP. Children also had a subjective improvement in daytime sleepiness.

CONCLUSIONS

Both CPAP and BPAP are highly efficacious in pediatric obstructive apnea. However, treatment with PAP is associated with a high dropout rate, and even in the adherent children, nightly use is suboptimal considering the long sleep hours in children.

Preoperative polysomnograms and infant pulmonary function tests do not predict prolonged postoperative mechanical ventilation in children following scoliosis repair

Our objective was the identification of children with scoliosis at higher risk of prolonged postoperative mechanical ventilation (MV) permits improved pre- and perioperative respiratory care to reduce postoperative complications. Pulmonary function testing (PFT) predicts prolonged postoperative MV in children who can reliably perform PFT, but some children cannot perform PFT. The objective of this study was to determine if polysomnography (PSG) or infant pulmonary function testing (IPFT) could predict prolonged postoperative MV (defined as MV >3 days) in children undergoing scoliosis surgery who could not reliably perform PFT. We studied 110 patients (age range, 10.8 +/- 4.9 [SD] years) who had preoperative PSG, and 18 patients (age range, 4.0 +/- 2.9 [SD] years) who had preoperative IPFT prior to undergoing any type of scoliosis repair by the Children's Hospital of Los Angeles Division of Orthopedic Surgery from January 1990- July 2001. The following information was reviewed and correlated: preoperative PSG parameters (baseline and nadir S(aO(2) ), baseline and peak P(ETCO(2) ), and apnea hypopnea index [AHI]), preoperative IPFT parameters (respiratory system compliance [C(rs)], respiratory system resistance [R(rs)], tidal volume [V(T)], and FRC), and length of postoperative MV. Twenty-seven patients (25%) who had PSG and 5 patients (28%) who had IPFT required postoperative MV >3 days. There was no association between baseline and nadir S(aO(2) ) <or= 92%, baseline and peak P(ETCO(2) ), or AHI, and length of postoperative MV. There was no association between IPFT (C(rs), R(rs), V(T), and FRC) and length of postoperative MV. We conclude that neither PSG nor IPFT can predict the need for prolonged postoperative MV following scoliosis surgery in children who could not reliably perform PFT.

Initiation of home mechanical ventilation in children with neuromuscular diseases

OBJECTIVE

To determine how often home mechanical ventilation (HMV) is instituted electively in children with respiratory failure from neuromuscular diseases and whether there were opportunities to discuss therapeutic options with patients/families before respiratory failure.

METHODS

Patients with neuromuscular disease (n = 73) requiring HMV (age, 2 months to 24 years) were studied. Whether HMV was initiated nonelectively because of acute respiratory failure or electively before acute respiratory failure, and opportunities for health care providers to discuss therapeutic options with patients/families before acute respiratory failure (hospitalization with pneumonia, clinic visits for preoperative evaluation, pulmonary function testing [PFT] and/or polysomnography [PSG]) were recorded.

RESULTS

HMV was initiated electively in 21% of patients with neuromuscular disease; 69% of the nonelective HMV group had HMV initiated after respiratory failure caused by pneumonia. In the nonelective group, opportunities for discussion of therapeutic options with the patients and families could have occurred before respiratory failure during 111 hospitalizations for pneumonia, 13 preoperative evaluations, 43 abnormal PFTs, and 24 abnormal PSGs.

CONCLUSIONS

Most patients with neuromuscular disease had HMV initiated nonelectively after acute respiratory failure caused by pneumonia. Opportunities for discussing the therapeutic options with patients and families before respiratory failure were missed or ineffective.

Cor triatriatum: a cause of hemoptysis

Hemoptysis can be caused by either pulmonary or extrapulmonary causes. Congenital heart disease should be considered as a possible cause in patients who have no obvious evidence of pulmonary disease. We report on an 8-year-old girl who presented with recurrent hemoptysis without other cardiopulmonary signs, except for mild tachypnea and a prominent pulmonic component of the second heart sound, suggesting pulmonary hypertension. A chest X-ray revealed pulmonary venous congestion without other parenchymal disease. An echocardiogram revealed classical cor triatriatum, with a 6-mm orifice in the anomalous septum. Cardiac evaluation should be considered in patients with hemoptysis unexplained by pulmonary causes, even in the absence of overt cardiac symptoms.