Naso-oesophageal probes decrease the frequency of sleep apnoeas in infants.
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The objective of the study was to determine whether a naso-oesophageal probe modifies sleep and cardiorespiratory patterns in infants with repeated obstructive apnoeas. Two polygraphic recording sessions were conducted in random order for 2 nights on 35 infants suspected to have repeated obstructive sleep apnoeas. One sleep study was performed with a pH probe inserted through the nasal passage down to the distal portion of the oesophagus. The other session was conducted without any naso-oesophageal probe (the baseline study). For the 25 infants who presented repeated obstructive apnoeas during baseline studies, the presence of the probe was associated with a small, but significant, decrease in the number of central apnoeas (median frequency of 18.5 apnoeas per hour without a probe; 16.1 per hour with the probe; P=0.040), and obstructive apnoeas (median of 1.9 apnoeas per hour without a probe; 0.6 per hour with the probe; P=0.016). The presence of the probe was also associated with a small increase in percentage non-rapid eye movement (NREM) sleep frequency. The changes were statistically significant only for infants who had no obstructive apnoea during baseline studies (29 vs. 31%). The presence of a naso-oesophageal probe significantly modifies the infants' respiratory characteristics during sleep. These findings should be considered when reporting and interpreting sleep studies in infants. (+info)
Are sleep studies worth doing?
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AIMS: To evaluate a sleep study service for children suspected of having sleep related upper airway obstruction (SRUAO). DESIGN: Prospective survey. SETTING: Paediatric and ear, nose, and throat clinics of the Royal Free Hampstead NHS Trust. SUBJECTS: Consecutively referred children with SRUAO symptoms. MAIN OUTCOME MEASURES: Sleep study data, referring clinician's impression, and completed symptom questionnaires. RESULTS: A total of 120 children (aged 6 months to 15.5 years) were studied. Study scores showed that 24 were classified as normal, 42 as mild, 33 as moderate, and 21 as severe SRUAO. In the 106 cases with matching data between clinician's impression and study score, 71 had good agreement, 18 were underestimated by the clinician, and 17 were over estimated. No cases reported as moderate or severe sleep apnoea by the study were referred by the clinician as normal. There were no important associations between parental symptom scores and sleep study scores. CONCLUSION: In children with suspected SRUAO, sleep studies do contribute to assessing the need for operation, the likelihood of postoperative respiratory failure, or as a baseline or outcome measure in intervention studies. (+info)
Two months auto-adjusting versus conventional nCPAP for obstructive sleep apnoea syndrome.
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Autoadjusting nasal continuous positive airway pressure (CPAP) greatly reduces the apnoea/hypopnoea index (AHI), and affords a significant reduction in median pressure (P50) compared-with manually titrated conventional nasal CPAP. The aim of the present study was to test whether these benefits were maintained in the medium term at home, in a double-blind crossover study. Ten sequential subjects (mean AHI 52.9 x h(-1)) were enrolled. After a manual titration, subjects were randomly allocated to 2 months autoadjusting nasal CPAP (AutoSet), followed by 2 months with the AutoSet device in fixed pressure mode at the manually titrated pressure, or vice versa. The machine-scored AHI, P50, and median leak were recorded on 12 nights in each arm, and averaged. Mean+/-SEM AHI was 4.0+/-0.3 x h(-1) in auto mode, and 3.7+/-0.3 x h(-1) in manual mode (NS). Mean+/-SEM P50 was 7.2+/-0.4 cmH2O auto, 9.4+/-0.6 cmH2O manual, average reduction 23+/-4% (p<0.0001). Auto "recommended" pressure was (mean+/-SEM) 10.1+/-0.5 cmH2O (p=0.04 with respect to manual) and peak pressure typically 1 cmH2O higher. Median (+/-SEM) leak was 0.181+/-0.006 L x s(-1) auto (and uncorrelated with AHI or pressure), 0.20+/-0.006 L x s(-1) manual (p=0.003). Compliance was 6.3+/-0.4 h in auto mode and 6.1+/-0.5 h in fixed mode (NS). Apnoea/hypopnoea index during 2 months of home autoadjusting nasal continuous positive airway pressure is comparable to that during conventionally titrated fixed pressure continuous positive airway pressure, while affording a 23% reduction in median pressure but no increase in compliance. Leak did not importantly affect autoadjustment. (+info)
Obstructive sleep apnoea syndrome is a common but underrecognised disorder with associated substantial morbidity and mortality. Excessive daytime sleepiness caused by the disorder leads to poor work performance and increases the risk of an individual having an automobile accident. The main objective of treatment for sleep apnoea is the relief of disabling daytime sleepiness and the improvement of quality of life. Conservative measures such as weight reduction and the avoidance of alcohol should be initiated when appropriate. Nasal continuous positive airway pressure devices have remained the standard treatment since it was first introduced in 1981. Oral appliances provide an alternative treatment choice in mild-to-moderate cases, whereas surgery is useful in selected cases. (+info)
Increases in leptin levels, sympathetic drive, and weight gain in obstructive sleep apnea.
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Patients with obstructive sleep apnea (OSA) are frequently obese and are predisposed to weight gain. They also have heightened sympathetic drive. We reasoned that noradrenergic activation of beta(3)-receptors on adipocytes would inhibit leptin production, predisposing to obesity in sleep apnea. We therefore tested the hypothesis that obesity and predisposition to weight gain in OSA are associated with low levels of plasma leptin. We prospectively studied 32 male patients (43 +/- 2 yr) with OSA who were newly diagnosed and never treated and who were free of any other diseases. Control measurements were obtained from 32 similarly obese closely matched male subjects (38 +/- 2 yr). Leptin levels were 13.7 +/- 1.3 and 9.2 +/- 1.2 ng/ml in patients with OSA and controls, respectively (P = 0.02). Weight gain over the year before diagnosis was 5.2 +/- 1.7 and 0.5 +/- 0.9 kg in sleep apnea patients and similarly obese control subjects, respectively (P = 0.04). Muscle sympathetic activity was 46 +/- 4 and 30 +/- 4 bursts/min in patients with OSA (n = 16) and control subjects (n = 18), respectively (P = 0.01). Plasma leptin levels are elevated in newly diagnosed otherwise healthy patients with untreated sleep apnea beyond the levels seen in similarly obese control subjects without sleep apnea. Higher leptin levels in OSA, independent of body fat content, suggest that OSA is associated with resistance to the weight-reducing effects of leptin. (+info)
Sleep-disordered breathing and occupational accidents.
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OBJECTIVES: The relationship between a common type of sleep disturbance, sleep-disordered breathing, and the risk of becoming involved in an occupational accident was studied. METHODS: A 10-year retrospective comparison was made of occupational injuries reported to the Occupational Injury Statistics Division of the Swedish National Board of Occupational Safety and Health. The injury rates for 704 consecutive patients suffering from sleep-disordered breathing were compared with the rates for an employed, age-matched random sample of 580 subjects, drawn from the general population. RESULTS: The risk of being involved in an occupational accident was about 2-fold among male heavy snorers and increased by 50% among men suffering from obstructive sleep apnea syndrome (OSAS). For females the risk increased by at least 3-fold among heavy snorers and OSAS patients. Reduced vigilance and attention due to sleep-disordered breathing are the proposed mechanisms behind the results. CONCLUSION: The early identification and treatment of persons suffering from sleep-disordered breathing would not only have positive impact on individual health and well-being but also on occupational safety. (+info)
Sustained isocapnic hypoxia suppresses the perception of the magnitude of inspiratory resistive loads.
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The sensation of increased respiratory resistance or effort is likely to be important for the initiation of alerting or arousal responses, particularly in sleep. Hypoxia, through its central nervous system-depressant effects, may decrease the perceived magnitude of respiratory loads. To examine this, we measured the effect of isocapnic hypoxia on the ability of 10 normal, awake males (mean age = 24.0 +/- 1.8 yr) to magnitude-scale five externally applied inspiratory resistive loads (mean values from 7.5 to 54.4 cmH(2)O. l(-1). s). Each subject scaled the loads during 37 min of isocapnic hypoxia (inspired O(2) fraction = 0.09, arterial O(2) saturation of approximately 80%) and during 37 min of normoxia, using the method of open magnitude numerical scaling. Results were normalized by modulus equalization to allow between-subject comparisons. With the use of peak inspiratory pressure (PIP) as the measure of load stimulus magnitude, the perception of load magnitude (Psi) increased linearly with load and, averaged for all loaded breaths, was significantly lower during hypoxia than during normoxia (20.1 +/- 0.9 and 23.9 +/- 1.3 arbitrary units, respectively; P = 0. 048). Psi declined with time during hypoxia (P = 0.007) but not during normoxia (P = 0.361). Our result is remarkable because PIP was higher at all times during hypoxia than during normoxia, and previous studies have shown that an elevation in PIP results in increased Psi. We conclude that sustained isocapnic hypoxia causes a progressive suppression of the perception of the magnitude of inspiratory resistive loads in normal subjects and could, therefore, impair alerting or arousal responses to respiratory loading. (+info)
Characterization of pharyngeal resistance during sleep in a spectrum of sleep-disordered breathing.
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Aims of the study were 1) to compare Hudgel's hyperbolic with Rohrer's polynomial model in describing the pressure-flow relationship, 2) to use this pressure-flow relationship to describe these resistances and to evaluate the effects of sleep stages on pharyngeal resistances, and 3) to compare these resistances to the pressure-to-flow ratio (DeltaP/V). We studied 12 patients: three with upper airway resistance syndrome (UARS), four with obstructive sleep hypopnea syndrome (OSHS), three with obstructive sleep apnea syndrome (OSAS), and two with simple snoring (SS). Transpharyngeal pressures were calculated between choanae and epiglottis. Flow was measured by use of a pneumotachometer. The pressure-flow relationship was established by using nonlinear regression and was appreciated by the Pearson's square (r(2)). Mean resistance at peak pressure (Rmax) was calculated according to the hyperbolic model during stable respiration. In 78% of the cases, the value of r(2) was greater when the hyperbolic model was used. We demonstrated that Rmax was in excellent agreement with P/V. UARS patients exhibited higher awake mean Rmax than normal subjects and other subgroups and a larger increase from wakefulness to slow-wave sleep than subjects with OSAS, OSHS, and SS. Analysis of breath-by-breath changes in Rmax was also a sensitive method to detect episodes of high resistance during sleep. (+info)