Improved detection of obstructive events in childhood sleep apnoea with the use of the nasal cannula and the differentiated sum signal

Nasal cannula use during polysomnography in children aged under three with suspected sleep apnea

OBJECTIVE

Early diagnosis of obstructive sleep apnea (OSA) in children is important. The use of a nasal cannula as an airflow sensor during polysomnography has not been evaluated in younger children. The study aims to evaluate the use of nasal cannula in detecting respiratory events in children under three with suspected OSA during daytime nap studies.

METHODS

A total of 185 patients were prospectively included. Respiratory events were scored using nasal cannula alone, thermistor alone, and both methods simultaneously as the airflow sensor. Agreement and diagnostic accuracy were assessed.

RESULTS

One hundred and seventy-two children were finally analyzed and 110 (64.0%) presented OSA. Total sleep time with an uninterpretable signal was longer with the nasal cannula than with the thermistor (17.8% vs 1.9%; p < 0.001), and was associated with poor sensor tolerance and adenotonsillar hypertrophy. In the estimation of the apnea-hypopnea index, the nasal cannula showed lower agreement than the thermistor with the joint use of the two sensors (intraclass correlation coefficient: 0.79 vs 0.996 with thermistor). Compared with the thermistor, the nasal cannula presented lower sensitivity for detecting OSA (82.7% vs 95.5%) and a lower negative predictive value (76.5% vs 92.4%). Overall, fewer children were diagnosed with severe OSA with the nasal cannula (19.8% vs 30.8% with the thermistor, and 32.6% with both).

CONCLUSIONS

In children under the age of three, the ability of the nasal cannula to detect obstructive events was relatively low. Therefore, other non-invasive measurements for identifying respiratory events during sleep may be of additional value.

Respiratory polygraphy in children with sleep-disordered breathing

At-home respiratory polygraphy has been shown to be a reliable substitute for in-laboratory polysomnography in adults for diagnosing obstructive sleep apnea, but this is less well studied in children. One aim of this study was to examine the quality of at-home respiratory polygraphy in children with sleep-disordered breathing and to evaluate the interrater reliability of the results. Another aim was to study whether calibrated respiratory inductance plethysmography (RIP) flow can be used for the scoring of respiratory events when the airflow measurements are unreliable. Children aged 4-10 years, with sleep-disordered breathing, underwent at-home respiratory polygraphy. Of 113 polygraphies, only 46% were of acceptable quality, with missing nasal airflow being the most common problem (40%). The median recorded time with artifact-free signal present in three traces simultaneously was 228 min (0-610 min). Seventeen polygraphy studies were selected for further study. Each study was scored by two independent scorers, with and without the nasal airflow signal present, the latter relying on RIP flow for the scoring of respiratory events. The apnea-hypopnea index (AHI) from the four different measurements was compared using intraclass correlation coefficients (ICC). Comparison of the two scorers showed moderate agreement, with (ICC = 0.66) and without (ICC = 0.53) nasal airflow. One scorer had good agreement between AHI with and without nasal airflow (ICC = 0.81), whereas the other had poor agreement (ICC = 0.12). In conclusion, the scoring of respiratory events based on RIP flow is scorer dependent even for experienced scorers. The nasal airflow signal is frequently missing in paediatric respiratory polygraphies, which limits the usefulness of the method.

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.

Severity of obstructive sleep apnea in children with sickle cell disease

OBJECTIVE

To characterize polysomnographic (PSG) findings of children with sickle cell disease (SCD) suspected of having sleep disordered breathing (SDB).

METHODS

Families of 100 consecutively referred children with SCD completed the Children's Sleep Habit Questionnaire during a routine visit to identify concerns regarding sleep habits and sleep behavior. Of these, 48 children were identified as displaying behaviors suspicious of SDB. Nineteen agreed to an overnight PSG. The results from the PSGs of the SCD with obstructive sleep apnea syndrome (OSAS) group (SCD-OSAS; group 1) were compared with the results of 10 age, sex, and ethnicity-matched patients identified as OSAS with no medical comorbidities (uncomplicated OSAS; group 2).

RESULTS

SDB was identified in 79% of the SCD group. As compared with the uncomplicated OSAS group, the SCD with OSAS group displayed nocturnal desaturation with lower nadir values, of longer duration, with a 4-fold increased risk for oxygen desaturation below 85%, higher percentage of total sleep time with end-tidal carbon dioxide (ET CO2) values >50 mm Hg, with a 3.7-fold increased risk for spending more than 25% of total sleep time with ET CO2 more than 50 mm Hg and higher peak ET CO2 with a 7-fold increase for peak ET CO2 above 53 mm Hg.

CONCLUSIONS

Children with SCD suspicious of SDB may have not only a higher incidence of OSAS, but also more severe nocturnal desaturation and hypercapnia as compared with children with uncomplicated OSAS.

Diagnosis and Evaluation of Obstructive Sleep Apnoea in Children

Introduction: The aim of this article is to review the medical literature and describe clinical and laboratory findings in children with obstructive sleep apnoea (OSA) to differentiate children with OSA from those with primary snoring or other disorders, with a particular focus on Asian children. Methods: Medline search via Pub Med, search terms sleep apnoea and children; and sleep apnoea and children and Asian. Results and Conclusions: Children with OSA usually present with snoring, daytime sleepiness, and/or difficulties in school or behaviour. The prevalence of OSA in Asian children is less than that of other groups, but the severity of the disorder on presentation may be greater. Overnight polysomnography remains the diagnostic “gold standard”; limited studies, or studies in the home, are not sufficient to exclude OSA in a child with suggestive symptoms, nor can they reliably assess the severity of the disorder which is important in planning treatment. Limited studies may, however, be useful in large-scale research studies. Key words: Asian, Polysomnography, Sleep studies, Snoring