Utilizing inspiratory airflows during standard polysomnography to assess pharyngeal function in children during sleep.

OBJECTIVES: Obstructive sleep apnea (OSA) is the result of pharyngeal obstruction that occurs predominantly during REM in children. Pathophysiologic mechanisms responsible for upper airway obstruction, however, are poorly understood. Thus, we sought to characterize upper airway obstruction in apneic compared to snoring children during sleep. We hypothesized that apneic compared to snoring children would exhibit an increased prevalence and severity of upper airway obstruction, that would be greater in REM compared to non-REM, and would improve following adenotonsillectomy. STUDY DESIGN: Apneic children were assessed with routine polysomnography before and after adenotonsillectomy, and compared to snoring children matched for gender, age, and BMI z-score. In addition to traditional scoring metrics, the following were used to characterize upper airway obstruction: maximal inspiratory airflow (%VI max) and percent of time with inspiratory flow-limited breathing (%IFL). RESULTS: OSA compared to snoring children had similar degrees of upper airway obstruction in non-REM; however, during REM, children with sleep apnea exhibited a higher %IFL (98 ± 2% vs.73 ± 8%, P < 0.01) and lower %VI max (56 ± 6 vs.93 ± 10%, P < 0.01). In children with OSA, CO2 levels were elevated during both wake and sleep. Following adenotonsillectomy, upper airway obstruction improved during REM manifest by decreased %IFL (98 ± 2 to 63 ± 9%, P = 0.04), increased %VI max (56 ± 6 to 95 ± 5%, P = 0.01) and decreased CO2 levels. CONCLUSIONS: Differences in the prevalence and severity upper airway obstruction suggest impaired compensatory responses during REM in children with OSA, which improved following adenotonsillectomy.

Polysomnographic Markers in Children With Cystic Fibrosis Lung Disease.

BACKGROUND AND OBJECTIVES: Children with cystic fibrosis (CF) often report poor sleep, increased daytime sleepiness, and fatigue. The purpose of this study was to identify respiratory patterns over the spectrum of disease severity in children with CF. The overall hypothesis for the current study is that children with CF compared with snoring control subjects demonstrate gas exchange abnormalities and increased respiratory loads during sleep that are not reported or recognized by conventional polysomnography (PSG). METHODS: Analysis of breathing patterns and gas exchange on PSG was performed in children with CF and healthy controls matched by age and BMI. For all CF and control subjects, the indication for PSG was evaluation for obstructive sleep apnea based on a history of snoring. RESULTS: Children with CF, compared with age- and BMI-matched snoring controls, demonstrated lower oxyhemoglobin saturation (95% ± 1.6% vs 98% ± 0.6%, P = .005), higher respiratory rate (19.5 ± 4.9 vs 16.5 ± 1.2 breaths per minute, P = .03), and a higher proportion of inspiratory flow limitation (44.1% ± 24.7% vs 12.1% ± 13.5%, P = .007) during non-rapid eye movement sleep. The respiratory disturbance index did not differ between CF and snoring control groups (1.5 ± 2.7 vs 0.6 ± 0.6 events per hour, P = .11). CONCLUSIONS: Children with CF exhibited abnormalities in gas exchange and increased respiratory load during sleep compared with normal age- and BMI-matched snoring controls. Because these abnormalities were independent of weight and lung function, sleep state may serve as an opportunity for early detection of breathing abnormalities and possibly CF lung disease progression.

Leptin and the control of pharyngeal patency during sleep in severe obesity.

RATIONALE: Obesity imposes mechanical loads on the upper airway, resulting in flow limitation and obstructive sleep apnea (OSA). In previous animal models, leptin has been considered to serve as a stimulant of ventilation and may prevent respiratory depression during sleep. We hypothesized that variations in leptin concentration among similarly obese individuals will predict differences in compensatory responses to upper airway obstruction during sleep. METHODS: An observational study was conducted in 23 obese women [body mass index (BMI): 46 ± 3 kg/m(2), age: 41 ± 12 yr] and 3 obese men (BMI: 46 ± 3 kg/m(2), age: 43 ± 4 yr). Subjects who were candidates for bariatric surgery were recruited to determine upper airway collapsibility under hypotonic conditions [pharyngeal critical pressure (passive PCRIT)], active neuromuscular responses to upper airway obstruction during sleep, and overnight fasting serum leptin levels. Compensatory responses were defined as the differences in peak inspiratory airflow (ΔVImax), inspired minute ventilation (ΔVI), and pharyngeal critical pressure (ΔPCRIT) between the active and passive conditions. RESULTS: Leptin concentration was not associated with sleep disordered breathing severity, passive PCRIT, or baseline ventilation. In the women, increases in serum leptin concentrations were significantly associated with increases in ΔVImax (r(2) = 0.44, P < 0.001), ΔVI (r(2) = 0.40, P < 0.001), and ΔPCRIT (r(2) = 0.19, P < 0.04). These responses were independent of BMI, waist-to-hip ratio, neck circumference, or sagittal girth. CONCLUSION: Leptin may augment neural compensatory mechanisms in response to upper airway obstruction, minimizing upper airway collapse, and/or mitigating potential OSA severity. Variability in leptin concentration among similarly obese individuals may contribute to differences in OSA susceptibility.

Polysomnography in preterm infants and children with chronic lung disease.

OBJECTIVE: To determine the utility of overnight polysomnography (PSG) in assessing pulmonary reserve in stable preterm children with chronic lung disease (CLD). STUDY DESIGN: A retrospective review and descriptive study of overnight PSGs and clinic visits of preterm infants/children less than 3 years of age who were diagnosed with bronchopulmonary dysplasia at discharge from the hospital and enrolled in the Johns Hopkins CLD patient registry between 2008 and 2010. RESULTS: Sixty-two clinically stable patients underwent at least one overnight polysomnogram for clinical indications. The majority of patients were referred for oxygen titration (71%). PSGs from first studies revealed a mean respiratory disturbance index (RDI) of 8.2 ± 10.1 events/hr and a mean O(2) saturation (SaO(2) ) nadir of 86.2 ± 5.7%. In patients who underwent more than one PSG (n = 23), a significant decrease in RDI (P < 0.001) was found between the first study (mean age: 8.0 ± 3.3 months) and second study (mean age: 13.4 ± 5.2 months). Outpatient clinical measures of mean room air SaO(2) and respiratory rate were not predictive of PSG measures of RDI and SaO(2) nadir. CONCLUSION: Mean RDI was higher in stable preterm infants/children with CLD compared to previously published controls. RDI decreased with age in stable preterm infants/children with CLD suggesting improved pulmonary reserve with age. Outpatient clinical measures (respiratory rate and room air SaO(2) ) did not correlate with RDI and SaO(2) nadir indicating that overnight PSG is more sensitive in assessing pulmonary reserve than outpatient clinical measures.

Characterization of obstructive sleep apnea before and after tongue-lip adhesion in children with micrognathia.

OBJECTIVES: To characterize airway obstruction before and after tongue-lip adhesion in children with micrognathia using polysomnography. DESIGN: Retrospective pilot case series. PARTICIPANTS AND METHODS: Evaluation of all children with micrognathia who underwent tongue-lip adhesion and polysomnography before and after surgery from 2002 to 2007 (N  =  8). RESULTS: Eight children met inclusion criteria; six were girls. The mean interval between polysomnography and tongue-lip adhesion was 6 days (range, 2 to 13 days) preoperatively and 17 days (range, 5 to 32 days) postoperatively. Severe obstructive sleep apnea was identified in seven of eight (88%) children, with a mean preoperative obstructive apnea hypopnea index of 52.6 events per hour (range, 7.1 to 85.7 events per hour). None had significant central sleep apneas (>5 per hour). Tongue-lip adhesion resulted in a mean decrease of 34.5 events per hour (range, -65.8 to 71.6 events per hour). After tongue-lip adhesion, seven of eight (87.5%) patients had an improved obstructive apnea hypopnea index, with resolution of obstructive sleep apnea in one child and improvement to mild (two) and moderate (two) obstructive sleep apnea in four others. Only one child had an obstructive apnea hypopnea index that increased after tongue-lip adhesion. Peak end-tidal pCO(2) measurements were elevated in all eight children before surgery at a mean of 60 mm Hg (range, 52 to 76 mm Hg) that improved to 51 mm Hg (range, 45 to 59 mm Hg), with normal peak levels in four children. Oxygen saturation nadir improved from 73% (range, 58% to 81%) to 82% (range, 65% to 94%). CONCLUSIONS: Tongue-lip adhesion may be performed in micrognathic infants to alleviate airway obstruction. Polysomnographic evaluation in this pilot study before and after surgery suggests that tongue-lip adhesion usually improves obstructive sleep apnea, but only 38% had complete resolution. Future studies of tongue-lip adhesion efficacy should include polysomnographic evaluation.

Day care increases the risk of respiratory morbidity in chronic lung disease of prematurity.

OBJECTIVES: Infants and children with chronic lung disease of prematurity (CLDP) are at increased risk for morbidity and mortality from respiratory viral infections. Exposure to respiratory viruses may be increased in the day care environment. The risk of respiratory morbidity from day care attendance in the CLDP population is unknown. We therefore sought to determine if day care attendance is a significant risk factor for increased respiratory morbidity and symptoms in infants and children with CLDP. METHODS: Between January 2008 and October 2009, parents of infants and children with CLDP were surveyed. Information on perinatal history, sociodemographic information, day care attendance, and indicators of respiratory morbidity, including emergency department (ED) visits, hospitalizations, systemic corticosteroid use, antibiotic use, and respiratory symptoms, was collected on children<3 years of age. Logistic regression models were constructed to examine associations between exposure to day care and respiratory morbidities. RESULTS: Data were collected from 111 patients with CLDP. The average gestational age was 26.2±2.0 weeks. Day care attendance was associated with significantly higher adjusted odds for ED visits (odds ratio [OR]: 3.74 [95% confidence interval (CI): 1.41-9.91]; P<.008), systemic corticosteroid use (OR: 2.22 [CI: 1.10-4.49]; P<.026), antibiotic use (OR: 2.40 [CI: 1.08-5.30]; P<.031), and days with trouble breathing (OR: 2.72 [CI: 1.30-5.69]; P<.008). Although there was an increased OR for hospitalization (OR: 3.22 [CI: 0.97-10.72]; P<.057), this did not reach statistical significance. CONCLUSIONS: We found that day care attendance is associated with increased respiratory morbidities in young children with CLDP. Physicians should consider screening for and educating caregivers about the risks of day care attendance by young children with CLDP.

Primary snoring and growth failure in a patient with cystic fibrosis.

An 8-year-old female with pancreatic-insufficiency cystic fibrosis presented with recurrent pharyngitis, and reduction in body mass index and height velocity during the previous 2 years. Her symptoms (eg, snoring and restless sleep) suggested obstructive sleep apnea, and physical examination revealed tonsillar hypertrophy. While her respiratory disturbance index on nocturnal polysomnography was normal, there was evidence of prolonged periods of snoring, associated with hypercapnia. Adenotonsillectomy decreased the snoring, improved her sleep, and in the 18-month follow-up period she had substantial weight-gain and growth improvement. This case demonstrates that adenotonsillar hypertrophy associated with recurrent pharyngitis and primary snoring might hinder growth in a patient with cystic fibrosis.

Treatment alternatives for sleep-disordered breathing in the pediatric population.

UNLABELLED: PURPOSE FOR REVIEW: Childhood sleep-disordered breathing (SDB) is associated with a myriad of health problems that underscore the need for early diagnosis and treatment. Children with SDB present with behavior problems, deficits of general intelligence, learning and memory deficits, evidence of brain neuronal injury, increased cardiovascular risk, and poor quality of life. Children are in a rapid state of cognitive development; therefore, alterations of health and brain function associated with SDB could permanently alter a child's social and economic potential, especially if the disorder is not recognized early in life or is treated inadequately. RECENT FINDINGS: There is evidence that the majority of the problems associated with SDB improve with treatment. Treatment strategies are now being aimed at mechanisms underlying the disorder. There are multiple treatment options available to children; some are novel, with pending treatments on the horizon that may replace age-old therapies such as adenotonsillectomy or nasal positive pressure. SUMMARY: It is imperative that healthcare workers actively seek out signs and symptoms of SDB in patients to improve early detection and treatment for prevention of long-term morbidity.

Periodic limb movements in sleep and iron status in children.

STUDY OBJECTIVES: To assess potential relationships between serum iron and ferritin levels and the severity of periodic limb movement in sleep (PLMS) in a pediatric population, and to evaluate the response to supplemental iron therapy. DESIGN: A prospective study of all consecutively diagnosed children with PLMS (periodic limb movement index [periodic limb movements per hour of total sleep time, [PLMI] > 5) who underwent overnight polysomnographic evaluation. In all patients, complete blood count and serum iron and ferritin levels were obtained. Patients with serum ferritin concentrations less than 50 microg/L were prescribed iron sulfate at 3 mg/kg of elemental iron per day for 3 months. At the end of treatment, serum iron and ferritin levels and sleep studies were repeated. SETTING: Comprehensive Sleep Medicine Center, Tulane University Health Sciences Center, and Kosair Children's Hospital Sleep Medicine and Apnea Center. PATIENTS: Twenty boys and 19 girls with PLMS with a mean age of 7.5 +/- 3.1 years. INTERVENTION: Iron therapy. RESULTS: Twenty-eight (71.8%) patients had ferritin levels less than 50 microg/L. There was no significant correlation between serum ferritin concentration and PLMS severity as indicated by the PLMI (r = -0.19). The PLMI in patients with serum ferritin levels less than 50 microg/L (29.9 +/- 15.5 PLM/h) was higher than in patients with serum ferritin levels greater than 50 microg/L (21.9 +/- 11.8 PLM/h); however, the difference did not achieve statistical significance (P = 0.09). In contrast, serum iron was significantly correlated with PLMI (r = -0.43, P < 0.01). Indeed, patients with serum iron concentrations less than 50 microg/dL had a higher PLMI compared to patients with serum iron concentrations greater than 50 microg/dL (42.8 +/- 18.3 PLM/h and 23.1 +/- 10.1 PLM/h, respectively; P = 0.02). Twenty-five out of the 28 PLMS patients with serum ferritin levels less than 50 microg/L received treatment with iron sulfate, and 19 (76%) responded favorably. Among the responders to iron therapy, PLMI decreased from 27.6 +/- 14.9 PLM per hour to 12.6 +/- 5.3 PLM per hour after 3 months of iron supplements (P < 0.001) and coincided with increases in serum ferritin levels (pre: 40.8 +/- 27.4 microg/L vs post: 74.1 +/- 13.0 microg/L; P < 0.001). CONCLUSIONS: In children, the presence of PLMS is frequently associated with low serum iron and a tendency toward low serum ferritin levels. In addition, iron therapy is associated with clinical improvement in most of these patients.