Ariel Tarasiuk

The effect of adenotonsillectomy on serum insulin-like growth factor-I and growth in children with obstructive sleep apnea syndrome

OBJECTIVE Obstructive sleep apnea syndrome (OSAS) in children is frequently associated with growth interruption. The objective of this study was to evaluate the effect of OSAS and adenotonsillectomy on the insulin-like growth factor-I (IGF-I) axis in children. STUDY DESIGN Thirteen prepubertal children (mean age, 6.0 +/- 2.8 years) were studied before and after adenotonsillectomy (T&A). Weight, height, overnight polysomnography, and IGF-I and IGF-binding protein-3 levels were evaluated before and 3 to 12 months after T&A. The childrens weights and heights were monitored for 18 months. RESULTS The respiratory disturbance index improved from 7.8 +/- 9.1 events/h to 1.0 +/- 2.1 events/h after T&A (P <.02). Slow-wave sleep increased from 29.1% +/- 7.2% to 34.6% +/- 9.8% after T&A (P <.02). The weight standard deviation score increased from 0.86 +/- 1 to 1. 24 +/- 0.9, 18 months after T&A (P <.01). Serum IGF-I levels increased from 146.3 +/- 76.2 ng/mL before T&A to 210.3 +/- 112.5 ng/mL after surgery (P <.01), but IGF-binding protein-3 levels did not change significantly. CONCLUSION The respiratory improvement after T&A in children with OSAS is associated with a significant increase in serum IGF-I levels and weight. We conclude that the IGF-I axis is affected in children with OSAS.

Propofol and Barbiturate Depression of Spinal Nociceptive Neurotransmission

Barbiturates are often described as non-analgesic or even hyperalgesic agents; the newer intravenous anesthetic agent propofol is said to be non-analgesic. Both propofol and barbiturates occupy sites on the GABAA receptor. The present study was designed to compare the effects of propofol and barbiturates on nociceptive-related neurotransmission in neonatal rat spinal cord; to search for actions that might be hyperalgesic; and to determine the extent to which propofol depression of nociceptive neurotransmission is mediated by GABAA receptors. The monosynaptic reflex, a slow ventral root potential (slow VRP) and the dorsal root potential (DRP) were recorded from isolated neonatal (1-5 days old) superfused rat spinal cords in response to electrical stimulation of a lumbar dorsal root. The slow VRP and the DRP are related to nociception. Propofol (0.5-10 microM), pentobarbital (1-10 microM), and thiopental (1-10 microM) reversibly depressed the slow VRP. Dose-response curves were monophasic and linear over this range. The monosynaptic reflex was unaffected. The GABAA agonist muscimol (0.2-1 microM) also depressed the slow VRP. Propofol and barbiturate slow VRP depression was antagonized by the GABAA antagonist bicuculline (1 microM). Propofol depressed the response evoked by direct application of substance P. The DRP is a GABAA-mediated depolarization of primary afferent nerve terminals that diminishes the effectiveness of nociceptive input. Propofol and thiopental increased electrically evoked DRP amplitude and increased the DRP evoked by application of muscimol. Both propofol and barbiturates thus depressed the nociceptive-related slow VRP and enhanced the antinociceptive DRP; their effective concentrations are at or close to the general anesthetic range for these agents. No anti-analgesic or hyperalgesic effect was observed. (ABSTRACT TRUNCATED AT 250 WORDS)

The Effect of Obstructive Sleep Apnea on Morbidity and Health Care Utilization of Middle‐Aged and Older Adults

OBJECTIVES: To determine whether elderly subjects with obstructive sleep apnea (OSA) had different morbidity and health care utilization than elderly subjects without OSA and middle‐aged patients with OSA 2 years before diagnosis.

Sleep quality predicts quality of life in chronic obstructive pulmonary disease

Purpose Chronic obstructive pulmonary disease (COPD) patients may suffer from poor sleep and health-related quality of life. We hypothesized that disturbed sleep in COPD is correlated with quality of life. Methods In 180 patients with COPD (forced expired volume in 1 second [FEV1] 47.6 ± 15.2% predicted, 77.8% male, aged 65.9 ± 11.7 years), we administered general (Health Utilities Index 3) and disease-specific (St George’s Respiratory) questionnaires and an index of disturbed sleep (Pittsburgh Sleep Quality Index). Results Overall scores indicated poor general (Health Utilities Index 3: 0.52 ± 0.38), disease- specific (St George’s: 57.0 ± 21.3) quality of life and poor sleep quality (Pittsburgh 11.0 ± 5.4). Sleep time correlated with the number of respiratory and anxiety symptoms reported at night. Seventy-seven percent of the patients had Pittsburg scores >5, and the median Pittsburgh score was 12. On multivariate regression, the Pittsburgh Sleep Quality Index was an independent predictor of both the Health Utilities Index 3 and the St George’s scores, accounting for 3% and 5%, respectively, of the scores. Only approximately 25% of the patients demonstrated excessive sleepiness (Epworth Sleepiness Scale >9). Conclusions Most patients with COPD suffer disturbed sleep. Sleep quality was correlated with general and disease-specific quality of life. Only a minority of COPD patients complain of being sleepy.

The economic impact of obstructive sleep apnea.

Purpose of review Obstructive sleep apnea (OSA) has a substantial economic impact on healthcare systems. We reviewed parameters affecting healthcare costs (race, low education, and socioeconomic status) on OSA comorbidity, and costs and the effect of OSA treatment on medical costs. Recent findings OSA is associated with increased cardiovascular disease (CVD) morbidity and substantially increased medical costs. Risk for OSA and resulting CVD are associated with obesity, tobacco smoking, black race, and low socioeconomic status; all these are associated with poor continuous positive airway pressure (CPAP) adherence. Healthcare costs are not normally distributed, that is, the costliest and the sickest upper third of patients consume 65–82% of all medical costs. Only a limited number of studies have explored the effect of CPAP on medical costs. Summary Costs of untreated OSA may double the medical expenses mainly because of CVD. Identifying the costliest, sickest upper third of OSA patients will reduce expenses to healthcare systems. Studies exploring the effect of CPAP on medical costs are essential. In addition, tailoring intervention programs to reduce barriers to adherence have the potential to improve CPAP treatment, specially in at-risk populations that are sicker and consume more healthcare costs.

A Cost-Effectiveness Analysis of Alternative At-Home or In-Laboratory Technologies for the Diagnosis of Obstructive Sleep Apnea Syndrome

Background . Obstructive sleep apnea syndrome (OSAS) is a common disorder that affects 2% to 9% of the population. Health care policy makers have noted increased referrals for sleep studies. Objective . In this article, the authors conduct a cost-effectiveness analysis to determine the optimal technology for the diagnosis of OSAS using polysomnography (PSG) or partial sleep monitoring (PSM). Design . The target population was a hypothetical cohort of patients suspected of having OSAS. A 2-level decision tree was formulated that reflects all possible steps of OSAS diagnosis and therapy. The method represents a comprehensive strategy to determine which of the 2 systems—PSG or PSM—has cost advantages. The financial and operational aspects of OSAS diagnosis and therapy were analyzed. A sensitivity analysis was performed over all uncertain parameters (i.e., diagnostic agreement, data loss, and referral to therapy). Results . Unattended at-home sleep monitoring was the most expensive method. The combination of 1:2 PSG and attended PSM strategy was the optimal strategy with respect to financing and operations. Compared to the PSG-only strategy, this combination may lead to a 10% reduction of the annual expenditure. Conclusion . This study provides proof of concept (under a wide range of sensitivity assumptions) that the cost of sleep study techniques can be modeled. It rejects the assumption that at-home portable sleep monitoring is cost advantageous. The combination of PSG and attended PSM OSAS is the most cost-effective approach to sleep evaluation.

Obstructive Apnea Hypopnea Index Estimation by Analysis of Nocturnal Snoring Signals in Adults

STUDY OBJECTIVE To develop a whole-night snore sounds analysis algorithm enabling estimation of obstructive apnea hypopnea index (AHI(EST)) among adult subjects. DESIGN Snore sounds were recorded using a directional condenser microphone placed 1 m above the bed. Acoustic features exploring intra-(mel- cepstability, pitch density) and inter-(running variance, apnea phase ratio, inter-event silence) snore properties were extracted and integrated to assess AHI(EST). SETTING University-affiliated sleep-wake disorder center and biomedical signal processing laboratory. PATIENTS Ninety subjects (age 53 ± 13 years, BMI 31 ± 5 kg/m(2)) referred for polysomnography (PSG) diagnosis of OSA were prospectively and consecutively recruited. The system was trained and tested on 60 subjects. Validation was blindly performed on the additional 30 consecutive subjects. MEASUREMENTS AND RESULTS AHI(EST) correlated with AHI (AHI(PSG); r(2) = 0.81, P < 0.001). Area under the receiver operating characteristic curve of 85% and 92% for thresholds of 10 and 20 events/h, respectively, were obtained for OSA detection. Both Altman-Bland analysis and diagnostic agreement criteria revealed 80% and 83% agreements of AHI(EST) with AHI(PSG), respectively. CONCLUSIONS Acoustic analysis based on intra- and inter-snore properties can differentiate subjects according to AHI. An acoustic-based screening system may address the growing needs for reliable OSA screening tool. Further studies are needed to support these findings.

Impaired behavioral and neurocognitive function in preschool children with obstructive sleep apnea.

We aimed to examine the hypothesis that behavioral and neurocognitive functions of preschool children with Obstructive Sleep Apnea Syndrome (OSAS) are impaired compared to healthy children, and improve after adenotonsillectomy (TA).

Automatic detection of whole night snoring events using non-contact microphone.

Objective Although awareness of sleep disorders is increasing, limited information is available on whole night detection of snoring. Our study aimed to develop and validate a robust, high performance, and sensitive whole-night snore detector based on non-contact technology. Design Sounds during polysomnography (PSG) were recorded using a directional condenser microphone placed 1 m above the bed. An AdaBoost classifier was trained and validated on manually labeled snoring and non-snoring acoustic events. Patients Sixty-seven subjects (age 52.5±13.5 years, BMI 30.8±4.7 kg/m2, m/f 40/27) referred for PSG for obstructive sleep apnea diagnoses were prospectively and consecutively recruited. Twenty-five subjects were used for the design study; the validation study was blindly performed on the remaining forty-two subjects. Measurements and Results To train the proposed sound detector, >76,600 acoustic episodes collected in the design study were manually classified by three scorers into snore and non-snore episodes (e.g., bedding noise, coughing, environmental). A feature selection process was applied to select the most discriminative features extracted from time and spectral domains. The average snore/non-snore detection rate (accuracy) for the design group was 98.4% based on a ten-fold cross-validation technique. When tested on the validation group, the average detection rate was 98.2% with sensitivity of 98.0% (snore as a snore) and specificity of 98.3% (noise as noise). Conclusions Audio-based features extracted from time and spectral domains can accurately discriminate between snore and non-snore acoustic events. This audio analysis approach enables detection and analysis of snoring sounds from a full night in order to produce quantified measures for objective follow-up of patients.

Extracellular ATP induces hyperpolarization and motility stimulation of ciliary cells

Cellular membrane potential and ciliary motility were examined in tissues cultures prepared from frog palate and esophagus epithelia. Addition of micromolar concentrations of extracellular ATP caused membrane hyperpolarization and enhanced the beat frequency. These two effects of ATP were 1) dose dependent, reaching a maximum at 10 microM ATP; 2) dependent on the presence of extracellular Ca2+ or Mg2+; 3) insensitive to inhibitors of voltage-gated calcium channels; 4) abolished after depleting the intracellular Ca2+ stores with thapsigargin; 5) attenuated by quinidine (1 mM), Cs+ (5-20 mM), and replacement of extracellular Na+ by K+; 6) insensitive to charybdotoxin (5-20 nM), TEA (1-20 microM), and apamin (0.1-1 microM); 7) independent of initial membrane potential; and 8) unaffected by amiloride. In addition, extracellular ATP induced an appreciable rise in intracellular Ca2+. Addition of thapsigargin caused an initial enhancement of the ciliary beat frequency and membrane hyperpolarization. These results strongly suggest the involvement of calcium-dependent potassium channels in the response to ATP. The results show that moderate hyperpolarization is closely associated with a sustained enhancement of ciliary beating by extracellular ATP.