Non-invasive ventilation usage and adherence in children and adults with Duchenne muscular dystrophy: A multicenter analysis.

INTRODUCTION/AIMS: Non-invasive ventilation (NIV) is routinely prescribed to support the respiratory system in Duchenne muscular dystrophy (DMD) patients; however, factors improving NIV usage are unclear. We aimed to identify predictors of NIV adherence in DMD patients. METHODS: This was a multicenter retrospective analysis of DMD patients prescribed NIV and followed at (1) The Hospital for Sick Children, Canada; (2) Rady Children's Hospital San Diego, USA; and (3) University of California San Diego Health, USA, between February 2016 and October 2020. The primary and secondary outcomes were 90-day period NIV adherence and clinical and socioeconomic predictors of NIV adherence. RESULTS: We identified 59 DMD patients prescribed NIV (mean ± SD age = 20.1 ± 6.7 y). Overall, percentage of nights used, and average nightly usage, were 79.9 ± 31.1% and 7.23 ± 4.12 h, respectively. Compared with children, adults had higher percentage of nights used (92.9 ± 16.9% vs. 70.4 ± 36.9%; P < .05), and average nightly usage (9.5 ± 4.7 h vs. 5.3 ± 3.7 h; P < .05). Non-English language (P = .01), and absence of deflazacort prescription (P = .02) were significantly associated with higher percentage of nights used while Hispanic ethnicity (P = .01), low household income (P = .02), and absence of deflazacort prescription (P = .02) were significantly associated with higher nightly usage. Based on univariable analysis, older age and declining forced vital capacity were associated with increased percentage of nights used and increased average nightly usage. DISCUSSION: Certain clinical and socioeconomic determinants had a significant impact on NIV adherence in DMD patients, providing insight into those at risk for high versus low compliance with respiratory therapy.

Reducing Mask-Related Pressure Injuries in Pediatric Patients During Noninvasive Ventilation by Targeting Patient Mask Leak: A Quality Improvement Initiative.

PURPOSE: To compare outcomes following implementation of patient mask leak range of 25 to 55 liters per minute (lpm) to guide strap tension of sleep masks during noninvasive ventilation against baseline data with no patient mask leak range on number of noninvasive mask-related pressure injuries (PIs). PARTICIPANTS AND SETTING: All noninvasively ventilated pediatric acute care patients admitted to general wards and intensive care units between February 1, 2018, and February 1, 2019, in a quaternary hospital in the southwest United States. APPROACH: Using the Plan Do Study Act model, we employed an intervention to examine the rate of PIs per noninvasive positive pressure ventilation (NIPPV) days and patient-days before and after implementation of patient mask leak parameters between 25 and 55 lpm to guide mask strap tension. Since patients are at an increased risk of sleep mask-related PIs only when on NIPPV, we sought to describe that as number or PIs per number of days at risk, described as NIPPV days, and patient days which is the traditional denominator for wounds and hospital-acquired conditions. OUTCOMES: Preintervention, 6 out of 115 subjects (5.2 %) incurred PI at a rate of 0.51 per 100 NIPPV days or 0.26 per 1000 patient-days. Of the 1932 NIPPV days since education was completed, only 1 subject out of 87 (1.1%) incurred a high-stage PI (0.05/100 NIPPV days-a 96.79% reduction or 0.05/1000 patient-days-a 92.86% reduction). Upon reaching more than 90% compliance with patient mask leak range in December 2018, 1221 NIPPV days resulted in 0 noninvasive mask-related PIs. Greater than 90% compliance with a patient mask leak of 25 to 55 lpm allowed us to successfully achieve our hospital's operating plan goal of 0.15 of 1000 patient-days within this group. IMPLICATIONS FOR PRACTICE: Maintaining a patient mask leak range between 25 and 55 lpm should be considered as part of proper fit for pediatric patients using NIPPV with a mask. Additional work is needed to assess this leak range in more children and in studies conducted at multiple sites.

Sleep disordered breathing in children with trisomy 13 and trisomy 18.

PURPOSE: While the prevalence of obstructive sleep apnea (OSA) is well documented in trisomy 21, there has been little published about the incidence in trisomy 13 (T13) and trisomy 18 (T18). Trisomies 13, 18, and 21 have overlapping clinical features that make patients prone to OSA. Because the literature regarding OSA in T13 and T18 children is limited, we performed a retrospective chart review to investigate the characteristics of these patients. METHODS: We reviewed the medical records of children with T13 or T18 seen at seen at a single urban tertiary children's hospital for sleep disordered breathing from 1/1/10 to 5/1/18. Candidates were selected based on ICD-9 diagnosis and procedural codes. RESULTS: We identified 21 T18 patients that had documented symptoms of SDB, of which 3 were diagnosed with OSA, 11 had clinical SDB, and 7 had snoring. Of the T13 patients, 10 had documented symptoms of SDB, of which 1 patient was diagnosed with OSA, 7 with clinical SDB, and 2 with snoring. In both T13 and T18 patients, anatomical features included micrognathia/mandibular hypoplasia, small mouth/small airway, midface hypoplasia, abnormal/difficult airway, glossoptosis, hypotonia, and GERD. Endoscopic findings included laryngomalacia and/or tracheomalacia, adenoid and lingual tonsil hypertrophy, and inferior turbinate hypertrophy. Surgical interventions performed in T13 and T18 patients included adenoidectomy, lingual tonsillectomy, and tracheostomy. Of the 32 T13 and T18 patients, 15 had to be intubated for respiratory insufficiency. CONCLUSION: The results of our study suggest that T13 and T18 patients are at increased risk for OSA due to common features found in this population. These findings indicate a need for otolaryngologist intervention to increase both survival and quality of life in this population.

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

STUDY OBJECTIVES: Current evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects. METHODS: Twenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures. RESULTS: Baseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose. CONCLUSIONS: These findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present.

Effectiveness of long-term noninvasive ventilation measured by remote monitoring in neuromuscular disease.

Background and objective: Patients with neuromuscular disease are often treated with home noninvasive ventilation (NIV) with devices capable of remote patient monitoring. We sought to determine whether long-term NIV data could provide insight into the effectiveness of ventilation over time. Methods: We abstracted available longitudinal data for adults with neuromuscular disease in monthly increments from first available to most recent. Generalised linear mixed-effects modelling with subject-level random effects was used to evaluate trajectories over time. Results: 1799 months of data across 85 individuals (median age 61, interquartile range (IQR) 46-71 years; 44% female; 49% amyotrophic lateral sclerosis (ALS)) were analysed, with a median (IQR) of 17 (8-35) months per individual. Over time, tidal volume increased and respiratory rate decreased. Dynamic respiratory system compliance decreased, accompanied by increased pressure support. Compared to volume-assured mode, fixed-pressure modes were associated with lower initial tidal volume, higher respiratory rate and lower pressures, which did not fully equalise with volume-assured mode over time. Compared with non-ALS patients, those with ALS had lower initial pressure support, but faster increases in pressure support over time, and ALS was associated wtih a more robust increase in respiratory rate in response to low tidal volume. Nonsurvivors did not differ from survivors in ventilatory trajectories over time, but did exhibit decreasing NIV use prior to death, in contrast with stable use in survivors. Conclusion: NIV keeps breathing patterns stable over time, but support needs are dynamic and influenced by diagnosis and ventilation mode. Mortality is preceded by decreased NIV use rather than inadequate support during use.

Leveraging Electronic Health Records for Guideline-Based Asthma Documentation.

BACKGROUND: Asthma is the most common pediatric chronic disease; thus, clinical guidelines have been developed for its assessment and management, which rely on systematic symptom documentation. Electronic health records (EHR) have the potential to record clinical data systematically; however, variability in documentation persists. OBJECTIVE: To identify if the use of a structured asthma template is associated with increased guideline-based asthma documentation and clinical outcomes when compared with the use of nonstructured ones. METHODS: We performed a retrospective case-control study comparing the use of nonstructured templates (NSTs) and asthma-structured templates (ASTs) in new patient and first follow-up encounters, evaluated by pediatric pulmonologists between March 2016 and December 2021. Asthma history items were selected following clinical guidelines, summarized in 29 items for new and 22 items for follow-up encounters. Associations with demographic, spirometry, and health care utilization were explored. RESULTS: A total of 546 initial encounters were included; 450 used structured templates. The use of an AST was associated with higher documentation of asthma items in initial and follow-up encounters. Linear regression analysis showed that the use of ASTs was associated with a 28.2% and 39.65% increase in asthma history completeness (in initial and follow-up encounters, respectively), compared with the use of NSTs. AST use was associated with higher rates of systemic steroid prescriptions within 12 months. No other differences were observed after adjusting for asthma severity. CONCLUSIONS: Using asthma-specific structured templates was associated with increased guideline-based asthma documentation. Leveraging the EHR as a clinical and research tool has the potential to improve clinical practice.

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.

Management and outcome of extreme pediatric obstructive sleep apnea.

OBJECTIVES: Classify post-adenotonsillectomy (AT) respiratory support, identify variables that predict these interventions, and evaluate outcomes in children with extreme obstructive sleep apnea (OSA). METHODS: Retrospective chart analysis was performed on patients found to have apnea/hypopnea index (AHI) > 100 events/h. Patients with chronic diseases other than obesity were excluded. RESULTS: Forty-one subjects were studied, average age of 11.4 ± 4.3 years, majority (73.1%) were Hispanic, with a mean total AHI (TAHI) of 128.1 ± 22.9/h. Twenty-eight (68.3%) patients underwent AT. Lower age (P < 0.001), lower BMI Z-score (P < 0.01), higher OAHI (P < 0.05) were associated with having surgery. Eleven out of 28 (39.3%) surgical patients required respiratory support (oxygen or positive airway pressure) postoperatively. Longer % total sleep time SpO2 <90% during PSG (P < 0.05) and lower SpO2 nadir (P < 0.05) were associated with requiring airway support. No patients experienced mortality, reintubation, or hospital readmission following AT, with majority (71.4%) discharged 1 day post-operatively. Eleven (57.9%) of the 19 patients who had a postoperative PSG had residual OSA, defined as AHI >5 events/h, but there was a significant improvement in TAHI (P < 0.01). CONCLUSION: Our findings confirm the need for postoperative observation in a controlled setting for patients with extreme OSA undergoing AT. Although at higher risk of needing respiratory support, those patients undergoing AT for extreme OSA did not require re-intubation post-operatively or suffer serious harm. Barring contraindications to AT, surgery may still be a first-line therapy for some children with extreme OSA.

Clinical implications of pulmonary nodules detected in children.

INTRODUCTION: The management of children found to have pulmonary nodules is not well established. We determined how often diagnostic testing was pursued, the outcome of diagnostic testing, and how often pulmonary nodules were given a definitive diagnosis. METHOD: A retrospective review of patients found to have pulmonary nodules. Patients with oncologic diagnoses were excluded. Data collected included number of nodules, presence of pre-existing systemic disease, laboratory testing, presence of respiratory symptoms, repeat imaging, biopsy result, and final diagnosis. RESULTS: We identified 88 patients, of which 56 (64%) had a single nodule, 21 (24%) had a pre-existing nononcologic systemic disease, and four patients (5%) had a new systemic disease identified at the same time the nodule(s) was found. In otherwise healthy patients presenting with a solitary nodule, 94% did not have a definitive diagnosis and none went on to be diagnosed with systemic disease. Serum infectious work-up result for tuberculosis, coccidioidomycosis, histoplasmosis, or aspergillosis was not significantly different between single and multiple nodule/systemic illness groups. No previously healthy patients presenting with a solitary nodule were later diagnosed with malignancy. CONCLUSION: Diagnostic workup for a solitary pulmonary nodule was often inconclusive, especially if the patient did not have symptoms at presentation. Pulmonary nodules were not the sole presenting sign of systemic disease for any subjects. We suggest that in an otherwise healthy pediatric patient found to have an asymptomatic single pulmonary nodule, observation without laboratory work-up or repeat imaging is a reasonable option.

Determinants of usage and nonadherence to noninvasive ventilation in children and adults with Duchenne muscular dystrophy.

STUDY OBJECTIVES: Duchenne muscular dystrophy (DMD) is a neuromuscular disorder that leads to chronic respiratory insufficiency and failure. Use of home noninvasive ventilation (NIV) has been linked to improved outcomes including reduced mortality. Despite the importance of NIV, factors promoting optimal NIV usage and determinants of nonadherence have not been rigorously examined. Moreover, given that respiratory issues in DMD span between childhood and adulthood, examination across a broad age group is needed. The objectives of this study were to (1) evaluate NIV usage across a broad spectrum of patients with DMD, including both children and adults, and (2) identify biological and socioeconomic determinants of NIV usage and NIV nonadherence. METHODS: We performed a retrospective review of all patients with DMD from February 2016 to February 2020 who underwent evaluation at associated pediatric and adult neuromuscular disease clinics. NIV use was determined objectively from device downloads. A priori, we defined nonadherence as < 4 hours use per night, quantified as the percentage of nights below this threshold across a 30-day period within 6 months of a clinic visit. We also assessed the average hours of NIV usage over this time period. Predictors examined included demographics, social determinants, and pulmonary function. RESULTS: 33 patients with DMD were identified, 29 (87%) of whom were using NIV (13 age < 21 years). Mean age was 22.9 ± 6.6 years (range 13-39 years), body mass index was 23.4 ± 10.4 kg/m2, and seated forced vital capacity was 23% ± 18% predicted. Mean nightly NIV usage was 7.4 ± 3.8 hours and mean percentage of nonadherent nights was 13% ± 30%. In univariable analysis, age did not predict use. Those with lower forced vital capacity had higher NIV usage hours (P = .01) and a trend toward less nonadherence (P = .06). Higher estimated household income demonstrated a trend toward increased usage hours and less nonadherence (both P = .08). Multivariable analysis found increased usage hours were predicted best by higher income, higher inspiratory positive airway pressure, and higher bicarbonate. Nonadherence was higher in those with lower income or higher forced vital capacity. CONCLUSIONS: In this cohort of adult and pediatric patients with DMD, most individuals were using NIV. While usage hours were higher with lower lung function, substantial variability remains unexplained by examined factors. Nonadherence was observed in some individuals, including those with advanced disease. Further investigations should focus on evaluating patient-oriented outcomes to define optimal NIV usage across the spectrum of disease and determine strategies to counteract issues with nonadherence. CITATION: Hurvitz MS, Bhattacharjee R, Lesser DJ, Skalsky AJ, Orr JE. Determinants of usage and nonadherence to noninvasive ventilation in children and adults with Duchenne muscular dystrophy. J Clin Sleep Med. 2021;17(10):1973-1980.

Findings of routine nocturnal polysomnography in children with Down syndrome: a retrospective cohort study.

STUDY OBJECTIVE: Children with Down syndrome (DS) are at risk for sleep disorders including; obstructive sleep apnea (OSA). Although OSA is diagnosed by polysomnography (PSG), the practicality of PSG in DS is questionable. Further, OSA treatment efficacy in DS is largely unknown given the challenges of PSG. Our aims were to review (i) the feasibility of PSG, and (ii) the efficacy (improvement in obstructive apnea hypopnea index (OAHI)) of OSA treatment using follow-up PSG in DS. METHODS: Retrospective review of patients aged <21 years with DS who underwent PSG from October 2016 to June 2019. Successful PSG was determined using total sleep time (TST). PSG following treatment with adenotonsillectomy (AT) or positive airway pressure (PAP) was evaluated and compared to pre-treatment. RESULTS: Among 248 patients with DS, only 11(4.4%) had unsuccessful PSG (TST<1h). Of the 237 successful studies (age: 7.9 ± 0.3y), average TST and sleep efficiency was 5.6 ± 0.1h and 79.5 ± 1.3%. 41 had post-AT PSG and 11(27%) achieved OSA cure (OAHI<2) with all demonstrating improved SE (p = 0.01) and OAHI (p = 0.0003). Multivariate analysis revealed only age was predictive (p = 0.003) of residual OSA post-AT. Of 24 children who underwent PAP titration, 20(83%) tolerated titration with improved OAHI (p = 0.01), however, no significant improvements in SE were observed. CONCLUSIONS: In a large cohort of DS children, PSG was well tolerated. Following AT or PAP therapy, post treatment PSG confirmed efficacy, although residual OSA was identified. PSG is thus both feasible and useful in identifying OSA, OSA treatment response and should guide in decision making in children with DS.

Multidisciplinary clinic for care of children with complex obstructive sleep apnea.

OBJECTIVE: While adenotonsillectomy (AT) remains first line therapy for pediatric obstructive sleep apnea (OSA), management of children who are not candidates for AT or who have residual OSA post AT varies and spans across multiple specialties. We aim to report our experience in managing this population through a multidisciplinary sleep clinic composed of specialists in pediatric dentistry, otolaryngology, plastic surgery, and pulmonary/sleep medicine. STUDY DESIGN: Retrospective chart review. METHOD: The medical records of children attending our complex sleep apnea clinic were reviewed. Data pertaining to demographics, underlying diagnoses, prior evaluation and treatment, recommendations, and initial therapy were collected. RESULT: Two-hundred and thirty patients (mean age 10.7 ± 5.1 years, 62.2% male) were assessed. Underlying conditions included Trisomy 21 (n = 65, 28.2%), other genetic syndromes (n = 37, 16.1%), obesity in an otherwise typically developing child (n = 36, 15.2%), cerebral palsy (n = 27, 11.7%), and craniofacial syndromes (n = 7, 3.0%). Mean obstructive apnea hypopnea index (OAHI) was 14.2 events/hour at first clinic visit, and the majority of children had previously undergone at least one upper airway surgery (n = 168, 73.0%), primarily adenotonsillectomy. Recommended initial treatment plans included positive airway pressure (PAP) therapy (n = 108, 47.0%), surgery (n = 75, 32.6%), allergy management (n = 52, 22.6%), and/or weight loss (n = 34, 14.8%). Patients prescribed PAP therapy with follow up data were found to be adherent 43.9% of the time. Surgical patients with post-operative polysomnography had pre-operative OAHI 15.6 ± SD13.4 decrease to 10.7 ± 14.2 events/hour (p = 0.61). CONCLUSION: Genetic conditions and obesity were the most common underlying diagnoses cared for in the complex sleep apnea clinic. Patients presented with severe OSA, most having already had upper airway surgery. Management plans were frequently adjusted, and we observed improvement in SDB in a sub-segment of patients, suggesting benefit to a coordinated, multi-disciplinary approach.

Congenital hypoventilation syndromes.

Although rare, congenital hypoventilation syndromes profoundly impact affected patients and families. In some diseases, such as congenital central hypoventilation syndrome (CCHS), hypoventilation is a key presenting feature. Ventilatory abnormalities may not be immediately evident in other disease states. The clinical aspects of several pediatric hypoventilation syndromes, including CCHS, Chiari type II malformation, Prader-Willi syndrome, familial dysautonomia, and rapid onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation are presented.

Diffuse panbronchiolitis: A progressive fatal lung disease that is curable with azithromycin, but only if diagnosed!

Diffuse panbronchiolitis (DPB) is a rare progressive and eventually fatal pulmonary disease first identified in Japan and initially seen predominantly in Southeast Asia. Macrolide antibiotics rapidly reverse symptoms and pathology, and their use increased the 5 and 10-year survival from 50 and 30 percent, respectively, to over 90%. Review of 181 case reports from previous publications found patients with DPB commonly had their pulmonary symptoms preceded by rhinosinusitis, frequently by many years. Long delays in diagnosis for many years were common. The review further identified DPB in all ethnic groups and multiple areas outside of Southeast Asia. Although diagnosis was most commonly made in adults, 13% of the diagnoses were made in children and nine of the adult cases described onset in childhood. Few cases of relapse were reported, but extended periods of monitoring after treatment were not generally present.

Noninvasive Ventilation Device-Related Pressure Injury in a Children's Hospital.

BACKGROUND: Noninvasive ventilation (NIV) contributes to the development of pressure injury in a significant number of hospitalized patients. Pressure injuries contribute to increased length of hospital stay, pain, infection, and disfigurement. This study examined the relationship between NIV use and pressure injuries in hospitalized subjects. METHODS: We retrospectively reviewed all patients on NIV at a tertiary-care children's hospital over a 2-y period. We studied the relationship between the characteristics of NIV use and measures of pressure injury severity. RESULTS: A total of 255 subjects, mean ± SD age 11.3 ± 5.8 y with 343 episodes of NIV use were evaluated, 7.2% (25/343) of which were associated with pressure injury. In univariate analysis, the presence of pressure injury was associated with older age (P = .01), maximum leak (P = .01), 95th percentile leak (P = .01), the log duration of time on NIV until pressure injury formation (P = .01), and maximum inspiratory positive airway pressure level (P = .01). Maximum leak remained statistically significant after multivariable analysis. CONCLUSIONS: After multivariate analysis, only high mask leak was significantly associated with developing a pressure injury. Identifying risk factors that correlate with NIV device-related hospital acquired pressure injuries in children can direct procedures to prevent pressure injury in hospitalized children at high risk.

Pneumothoraces in collagen VI-related dystrophy: a case series and recommendations for management.

Collagen VI-related dystrophy (collagen VI-RD) is a rare neuromuscular condition caused by mutations in the COL6A1, COL6A2 or COL6A3 genes. The phenotypic spectrum includes early-onset Ullrich congenital muscular dystrophy, adult-onset Bethlem myopathy and an intermediate phenotype. The disorder is characterised by distal hyperlaxity and progressive muscle weakness, joint contractures and respiratory insufficiency. Respiratory insufficiency is attributed to chest wall contractures, scoliosis, impaired diaphragmatic function and intercostal muscle weakness. To date, intrinsic parenchymal lung disease has not been implicated in the inevitable respiratory decline of these patients. This series focuses on pneumothorax, an important but previously under-recognised disease manifestation of collagen VI-RD. We describe two distinct clinical presentations within collagen VI-RD patients with pneumothorax. The first cohort consists of neonates and children with a single pneumothorax in the setting of large intrathoracic pressure changes. The second group is made up of adult patients with recurrent pneumothoraces, associated with chest computed tomography scan evidence of parenchymal lung disease. We describe treatment challenges in this unique population with respect to expectant observation, tube thoracostomy and open pleurodesis. Based on this experience, we offer recommendations for early identification of lung disease in collagen VI-RD and definitive intervention.

Evaluation of phrenic nerve and diaphragm function with peripheral nerve stimulation and M-mode ultrasonography in potential pediatric phrenic nerve or diaphragm pacing candidates.

Assessing phrenic nerve function in the setting of diaphragmatic paralysis in diaphragm pacing candidates can be challenging. Traditional imaging modalities and electrodiagnostic evaluations are technically difficult. Either modality alone is not a direct measure of the function of the phrenic nerve and diaphragm unit. In this article, the authors present their method for evaluating phrenic nerve function and the resulting diaphragm function. Stimulating the phrenic nerve with transcutaneous stimulation and directly observing the resulting movement of the hemidiaphragm with M-mode ultrasonography provides quantitative data for predicting the success of advancing technologies such as phrenic nerve pacing and diaphragm pacing.

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.

The utility of a portable recording device for screening of obstructive sleep apnea in obese adolescents.

STUDY OBJECTIVES: The ApneaLink Plus is a portable recording device that measures air flow, respiratory effort, heart rate, and pulse oximetry. In the current study, we asked whether this device could be used to screen for obstructive sleep apnea in the pediatric population. METHODS: Sleep-laboratory polysomnography (PSG) was performed simultaneously with measurements using the portable device on obese pediatric patients referred for snoring. The obstructive apnea hypopnea index (OAHI) was calculated automatically by the device (autoscore) and manually by the investigators. Sensitivity, specificity, correlation, and receiver operating curves (ROC) were used to compare the portable device to PSG. RESULTS: Twenty-five subjects (60% male, mean age 13.6 ± 3.0 years, OAHI on PSG 11.8 ± 27.1) were studied. We identified a significant correlation between the OAHI of the ApneaLink autoscore and PSG (Spearman Rho = 0.886 [p < 0.001]). Using the PSG results as standard, ROC curves comparing the ApneaLink OAHI with the PSG OAHI demonstrated high congruence. The autoscore agreement was very good at PSG OAHI > 1.5 (area under the receiver operating curve [AUC] 0.965, OAHI > 5 [AUC 0.937], and OAHI > 10 [AUC 1.00]). The agreement of the manual score and autoscore were essentially equivalent. The device's autoscore demonstrated high sensitivity at all cutoffs examined (100% at OAHI > 1.5, 85.7% at OAHI > 5, and 100% at OAHI > 10). The specificity increased with increasing cutoffs (46.2% at OAHI > 1.5, 83.3% at OAHI > 5, and 90.0% at OAHI > 10). CONCLUSION: he ApneaLink Plus is a sensitive screening tool for evaluation of suspected OSAS in obese pediatric patients aged 9-18 years. The specificity improves with increasing OAHI cutoffs. The device detects OSAS when tested in a sleep laboratory on obese adolescents referred for symptoms of sleep related breathing disorder.

Does the 6-min walk test correlate with the exercise stress test in children?

Is there a correlation between the 6-min walk and aerobic fitness in children? We studied healthy and cystic fibrosis (CF) subjects age 8-20 years using the 6-min walk test, treadmill graded exercise stress test, and spirometry. Six-minute walk distance (6MWD) and the product of 6MWD and body weight (6MWORK) were related to aerobic capacity. Data were analyzed using Student's t-test and Pearson correlation. 13 healthy subjects [9 females, mean age 15.8 +/- 3.6 years, % predicted forced expiratory volume in one second (FEV(1)) 105 +/- 12%, 6MWD 557 +/- 73 m, peak oxygen uptake (V' O2 max) 41.4 +/- 7.2 ml/kg/min, and heart rate (HR) at V' O2 max 180 +/- 10] and 11 CF subjects (3 females, mean age 14.3 +/- 3.8 years, FEV(1) 67 +/- 25.9%, 6MWD 468 +/- 68 m, V' O2 max 27.0 +/- 8.1 ml/kg, and HR at V' O2 max 163 +/- 22] were studied. 6MWD correlates with V' O2 max in normal subjects (r = 0.59, P < 0.05) but not in CF subjects (r = 0.09, NS). 6MWORK correlates with V' O2 max in CF subjects (r = 0.65, P < 0.05) but not in normal subjects (r = 0.278, NS). We conclude that the 6MWD corresponds with aerobic fitness in normal pediatric subjects and 6MWORK corresponds with aerobic fitness in CF subjects. We speculate that 6MWORK is superior to 6MWD for assessment of aerobic fitness in children with CF.