Estimating sleep time from non-EEG-based PSG signals in the diagnosis of sleep-disordered breathing.

PURPOSE: The purpose of this study was to use non-EEG PSG signals to estimate TST in order to diagnose SDB with a greater sensitivity than type 3 device methodology that relies on TRT. METHODS: Movement patterns were obtained from the thoracoabdominal signals of adult PSG recordings (n = 60) in the laboratory and the home. Parameters obtained allowed, with 95% certainty, identification of sleep and wake based on the duration of movements and quiescent time (Qd). Snoring, apneas, and hypopneas indicated sleep with 100% certainty. The method was tested in a different set of PSG recordings (n = 80). RESULTS: Subjects lay awake and immobile for longer in the laboratory (QdLAB = 27.4 (12.1, 62.0), QdHOME = 16.0 s (8.0, 36.0); p < 0.0001) but asleep and immobile for longer at home (QdLAB = 65.2 (23.0, 121.4), QdHOME = 95.0 s (44.5, 247.5); 0.005). Only 5% of wake Qd periods were >173 s in the laboratory and >105 s at home. In both locations, 95% of movements during sleep were <10 s. Experimental TST values were 21 min shorter than EEG-defined TST and, combined with fewer scored respiratory events, produced AHI values that were 1.6 events/h lower than the reference. The experimental TST increased the sensitivity of SDB diagnosis from 73 to 97%. CONCLUSIONS: In the sleep laboratory, subjects are immobile for longer periods when awake and for shorter periods when asleep. The experimental TST was similar to EEG-defined TST and could be used to diagnose SDB with a much higher sensitivity than the type 3 method.

Hypertension, snoring, and obstructive sleep apnoea during pregnancy: a cohort study.

OBJECTIVE: To assess the frequency of obstructive sleep apnoea among women with and without hypertensive disorders of pregnancy. DESIGN: Cohort study. SETTING: Obstetric clinics at an academic medical centre. POPULATION: Pregnant women with hypertensive disorders (chronic hypertension, gestational hypertension, or pre-eclampsia) and women who were normotensive. METHODS: Women completed a questionnaire about habitual snoring and underwent overnight ambulatory polysomnography. MAIN OUTCOME MEASURES: The presence and severity of obstructive sleep apnoea. RESULTS: Obstructive sleep apnoea was found among 21 of 51 women with hypertensive disorders (41%), but in only three of 16 women who were normotensive (19%, chi-square test, P=0.005). [Author correction added on 16 June 2014, after first online publication: Results mentioned in the abstract were amended.] Non-snoring women with hypertensive disorders typically had mild obstructive sleep apnoea, but >25% of snoring women with hypertensive disorders had moderate to severe obstructive sleep apnoea. Among women with hypertensive disorders, the mean apnoea/hypopnoea index was substantially higher in snorers than in non-snorers (19.9±34.1 versus 3.4±3.1, P=0.013), and the oxyhaemoglobin saturation nadir was significantly lower (86.4±6.6 versus 90.2±3.5, P=0.021). Among women with hypertensive disorders, after stratification by obesity, the pooled relative risk for obstructive sleep apnoea in snoring women with hypertension compared with non-snoring women with hypertension was 2.0 (95% CI 1.4-2.8). CONCLUSIONS: Pregnant women with hypertension are at high risk for unrecognised obstructive sleep apnoea. Although longitudinal and intervention studies are urgently needed, given the known relationship between obstructive sleep apnoea and hypertension in the general population, it would seem pertinent that hypertensive pregnant women who snore should be tested for obstructive sleep apnoea, a condition believed to cause or promote hypertension.

Increasing hospitalizations for serious skin infections in New Zealand children, 1990-2007.

The incidence of serious skin infections in New Zealand children is significantly higher than in comparative countries. This study aimed to describe the epidemiology of these infections and identify changes in disease distribution over time. Discharge data were analysed for all children admitted to a New Zealand public hospital with a serious skin infection during the period 1990-2007. Patient and admission variables were compared between 1990-1999 and 2000-2007. The incidence of serious skin infections almost doubled from 298·0/100,000 in 1990 to 547·3/100,000 in 2007. The highest rates were observed in boys, preschool-aged children, Maori and Pacific children, those living in deprived neighbourhoods, urban areas and northern regions. Over time there were disproportionate increases in infection rates in Maori and Pacific children and children from highly deprived areas. Serious skin infections are an increasing problem for New Zealand children. Worsening ethnic and socioeconomic health inequalities may be contributing to increasing rates.

Enzymatic methylation of microsomal metabolites of benzo(a)pyrene.

These studies suggest that the microsomal metabolism of benzo(a)pyrene (BP) produces metabolites which can be methylated by the catechol-o-methyltransferase (COMT)/S-adenosylmethionine (SAM) enzyme/donor combination. Induced microsomes converted 12 to 15% of substrate BP to polar products. Approximately 0.06% of substrate BP was recovered as COMT/SAM-reactive substances. In tests for specificity, COMT/SAM was found to react with catechols, but not with dihydrodiols, quinones, a phenol, an epoxide, or 1,4-hydroquinone. Organic extracts of COMT/[14C]SAM incubations with BP were fractionated by high-performance liquid chromatography. The appearance of radiolabeled chromatographic bands required the presence of substrate BP, microsomes, and COMT/[14C]SAM. When the Ames mutagenesis assay was supplemented with COMT/SAM, a 36% reduction was observed in the number of revertant colonies induced by the microsomal oxidation of BP. In contrast, the mutagenic properties of 2-aminofluorene were not affected by COMT/SAM. These observations indicate that COMT/SAM does not generally inhibit mixed-function oxidase activity but rather reacts with substances which are activated by ring oxygenations.

Neuroendocrine dysfunction in sleep apnea: reversal by continuous positive airways pressure therapy.

We studied the effects of sleep apnea on neuroendocrine function in a cross-sectional study of 225 consecutive men undergoing sleep studies and in a longitudinal study of 43 men with severe obstructive sleep apnea before and after 3 months of successful treatment with nasal continuous positive airways pressure to eliminate upper airways obstruction. Blood samples were collected at 0600-0630 h on awakening for measurement of plasma insulin-like growth factor I (IGF-I), total and free testosterone, sex hormone-binding globulin (SHBG), LH, FSH, PRL, T4, T4-binding globulin, and cortisol. The plasma hormone levels were analyzed in relation to the severity of sleep apnea, as indicated by the desaturation index (the hourly rate of episodes of arterial oxygen desaturation greater than 4% of the stable baseline) and the mean minimal oxygen saturation during the desaturation episodes. In the cross-sectional study plasma IGF-I, free and total testosterone, and SHBG levels were significantly lower in relation to the severity of sleep apnea, whereas plasma LH, FSH, PRL, T4, T4-binding globulin, and cortisol were not. The decreases in plasma IGF-I and total and free testosterone were independent of the effects of aging and adiposity by covariance analysis. In the longitudinal study plasma IGF-I, total testosterone, and SHBG, but not free testosterone, significantly increased after 3 months of nasal continuous positive airways pressure treatment. We conclude that sleep apnea causes reversible neuroendocrine dysfunction in men, which is manifested by decreased plasma. IGF-I, testosterone, and SHBG levels. This neuroendocrine dysfunction is related to the severity of the sleep apnea, as indicated by the nadir levels of arterial oxygen desaturation and the rate of desaturation episodes. These hormonal measurements may provide biochemical markers for both the severity of sleep apnea and its response to therapeutic intervention. In addition, sleep apnea may be a previously unrecognized confounder of the neuroendocrine correlates of aging.

Obstructive sleep apnea in obese noninsulin-dependent diabetic patients: effect of continuous positive airway pressure treatment on insulin responsiveness.

Patients with noninsulin-dependent diabetes mellitus (NIDDM) are often obese and frequently complain of tiredness. These features are also characteristically seen in patients with obstructive sleep apnea (OSA). Therefore, it was the aim of this study to assess the prevalence of OSA among a group of obese NIDDM patients who have some clinical features of OSA. The effect of reversal of OSA by nasal continuous positive airway pressure (CPAP) treatment on insulin responsiveness was also investigated. From a population of 179 NIDDM patients with a body mass index (BMI) greater than 35 kg/m2, we performed ambulatory sleep monitoring on 31 (15 males and 16 females) who admitted to either heavy snoring or excessive sleepiness. Results were reviewed by a sleep physician blinded to the clinical status of the patients, and 22 (70%) were found to have moderate or severe OSA, with mean oxygen desaturation indexes of 10.3 +/- 5.3 and 30.7 +/- 13.2 episodes/h, respectively. A subgroup of 10 patients (seven males and three females) with a mean BMI of 42.7 +/- 4.3 kg/m2 was treated with nightly CPAP for 4 months. These subjects all had significant OSA, with frequent obstructive apneas (mean, 47 +/- 31.6 episodes/h) and oxygen desaturation (mean minimum O2 saturation, 74 +/- 9.5%), as determined by polysomnography. One patient was excluded from analysis because of infrequent use of CPAP. Insulin responsiveness in terms of glucose disposal measured by hyperinsulinemic euglycemic clamps improved from 11.4 +/- 6.2 to 15.1 +/- 4.6 mumol/kg.min (P < 0.05) during CPAP treatment. These results indicate that OSA occurs commonly in obese NIDDM patients with excessive sleepiness or heavy snoring. Treatment of their OSA may improve insulin responsiveness.

Sleep apnea and hypothyroidism: mechanisms and management.

PURPOSE: There is a high incidence of sleep apnea in patients with untreated hypothyroidism. Thyroxine treatment is said to significantly reduce the apnea index and length and sleep apnea symptoms. We undertook a review of 10 consecutive hypothyroid patients with sleep apnea to investigate mechanisms and management of these two disorders. PATIENTS AND METHODS: Polysomnograms were obtained in 10 consecutive hypothyroid patients referred to our sleep disorders unit. All patients were studied while hypothyroid. Eight patients were restudied later when euthyroid. Lung function, blood gas values, and awake supraglottic resistance were also assessed in each patient. RESULTS: All 10 patients had sleep apnea and were treated with thyroxine. In one patient, hypothyroid myopathy involving the upper airway was demonstrated to be a potential mechanism of sleep apnea in hypothyroidism. Nocturnal angina and ventricular arrhythmias developed in two patients, despite the use of low thyroxine doses. Nasal continuous positive airways pressure (CPAP) was begun in eight patients. Initiation of CPAP prevented further angina or arrythmia in the patients with these cardiac complications. Six of the eight patients who were available for follow-up studies had persistent sleep apnea despite an euthyroid status (apnea index before thyroxine, 51 +/- 6; apnea index after thyroxine, 45 +/- 8), and CPAP therapy was continued in these patients. CONCLUSION: Our experience suggests that the apnea index does not decrease significantly in all patients with hypothyroidism and sleep apnea when euthyroidism is achieved. Treatment of hypothyroidism in the presence of sleep apnea is potentially hazardous and may lead to cardiovascular complications. Management by a combination of CPAP and low-dose thyroxine is helpful in this situation.

Sleep-disordered breathing and its effects on sleep in infants.

Sleep apnea has been recorded in many infants, but little data exist concerning the amount and range of apnea in infants. We studied 49 infants referred to the sleep disorders unit. Single polysomnographic studies were performed on each infant. We examined the amount of apnea, presence and amount of upper airway obstruction and the sleeping pattern in each infant. Central apnea was common to all infants and varied in amount. Upper airway obstruction, recorded as mixed apnea, was found in 36 infants. Twenty of these infants had only occasional mixed apnea ( < 2 apneas/hour), whereas 16 infants displayed a higher amount of obstruction. All infants were separated into two groups according to amount of apnea and obstruction. Sixteen infants with obstruction plus 3 infants with a high amount of central apnea represented group I. The remaining 30 infants represented group II. Marked differences in the sleeping pattern were found when the groups of infants were separated. Infants from group I had significantly less rapid eye movement (REM) sleep than infants from group II. We conclude that sleep-disordered breathing in infants is associated with disruptions in sleep.

Treatment of obstructive sleep apnea syndrome in children.

Obstructive sleep apnea (OSA) has been identified and recorded in paediatric patients, the potential mechanisms for OSA include anatomical abnormalities that lead to a narrowed airway space, reduced muscle tone and abnormal central ventilatory control. Several treatments have been developed and are routinely used to treat OSA in infants and children. Nasal mask continuous positive airway pressure (CPAP) is an effective non-invasive treatment that prevents the majority of obstructive events, reverses sleep disturbances, improves daytime performance and is associated with increased growth in patients with failure to thrive. Surgery to correct underlying anatomical abnormalities is frequently used and usually results in an improvement in symptoms and in some cases, it is curative. Other forms of treatment include pharmacological interventions, positioning and nasopharyngeal intubation.

Nasal continuous positive airway pressure treatment: current realities and future.

Nasal continuous positive airway pressure (CPAP) is a highly effective treatment for obstructive sleep apnea syndrome. The apnea/hypopnea index (AHI) is reduced 10-fold, but the patient dropout rate is up to 30%, and usage is typically < 5 hours per night. Titration, designed to make the best trade-off between effectiveness and side effects, is expensive. Autotitrating devices make this trade-off on a minute-by-minute basis, potentially reducing mean pressure delivery, reducing side effects, and increasing compliance. The aim of this study was to test the effectiveness of the AutoSet self-adjusting nasal CPAP system (ResMed, Sydney, Australia) in eliminating obstructive events and normalizing the arousal index. Forty-five subjects (41 males and 4 females with AHI) values of > 20/hour were recruited, with written informed consent. Subjects slept for a diagnostic night, followed by a treatment night, in the laboratory, using the AutoSet system with full polysomnographic monitoring of respiratory and sleep variables. Arousals were scored using ASDA criteria. Hypopneas were scored when there was a 50% reduction in ventilation for > 10 seconds, associated with a 4% drop in oxygen saturation. For comparison, the ASDA arousal index in 16 normal subjects (without nasal CPAP) is provided. Results are given as mean +/- standard error of the mean. AHI was reduced from 55 +/- 3 to 1.5 +/- 0.35 events/hour (p < 0.0001). The arousal index was reduced from 65 +/- 3 to 18 +/- 2 events/hour (p < 0.0001), identical to the value in the 16 healthy normal subjects. There was a 158% +/- 21% increase in slow-wave sleep (p = 0.01) and a 186% +/- 27% increase in rapid eye movement sleep (p = 0.013). The AutoSet self-adjusting nasal CPAP system adequately treats obstructive sleep apnea syndrome on the first night under laboratory conditions.

Acute withdrawal of nasal CPAP in obstructive sleep apnea does not cause a rise in stress hormones.

We hypothesized that withdrawal of nasal continuous positive airway pressure (CPAP) in patients with sleep apnea would produce a measurable stress response. To test this hypothesis, we ceased CPAP in eight patients regularly using nasal CPAP long term and measured the effect on sleep apnea as well as plasma and urinary levels of the stress hormones, noradrenaline, cortisol and adrenocorticotropic hormone (ACTH). CPAP withdrawal led to an immediate recurrence of sleep apnea with increases in apnea index, arousal index and oxygen desaturation (all p < .0001) but no change in levels of noradrenaline, cortisol or ACTH. We conclude that acute withdrawal of CPAP in patients with sleep apnea does not lead to a classic stress response.

Pre-eclampsia is associated with marked alterations in sleep architecture.

STUDY OBJECTIVES: Pre-eclampsia is currently the predominant cause of maternal and fetal morbidity and mortality. Diurnal blood pressure variation is flattened or reversed in pre-eclampsia; however, sleep has not been extensively investigated in this disease. Our objective was therefore to study sleep architecture in this group of patients. STUDY DESIGN: Full polysomnography using the Compumedics Sleepwatch System or Compumedics p-series. SETTING: NA. PATIENTS: 25 pre-eclamptic patients and 17 primigravidas with normal pregnancies and no history of cardiovascular disease or sleep disorder. With the exception of one subject, all pre-eclamptics were taking clonidine (a known suppressant of rapid eye movement-REM-sleep) for control of their hypertension. INTERVENTIONS: NA. RESULTS: Pre-eclamptic subjects had markedly altered sleep architecture, with a markedly increased percentage of time spent in slow-wave sleep (SWS) (21 * 2% versus 43 * 3%, p<0.001). There was a longer latency to rapid eye movement (REM) sleep (92 * 11 mins vs. 205 * 23 mins in control and pre-eclamptic subjects, respectively, p<0.001) and reduced time spent in REM (18 * 1% and 10 * 2% in control and pre-eclamptic subjects, respectively, p<0.001). CONCLUSIONS: While the increased REM latency and decreased REM time are most likely due to clonidine, this is unlikely to also account for the increased SWS. Two possible explanations for this include cerebral edema and release of cytokines, which are known to alter sleep structure.

Effect of nasal continuous positive airway pressure during sleep on 24-hour blood pressure in obstructive sleep apnea.

Ambulatory blood pressure (BP) was measured noninvasively (Oxford Medilog ABP) at 15-minute intervals for 24 hours before and after 8 weeks of treatment with nasal continuous positive airway pressure (nCPAP) in 19 men with obstructive sleep apnea (OSA). We included both normotensive and hypertensive patients, but hypertensives were studied after withdrawal of antihypertensive drugs. Ambulatory BP before and after treatment was compared using patients as their own controls. Treatment with nCPAP was successfully established in 14 of the 19 patients (74%). Blood pressure fell significantly in patients who were successfully treated: 24-hour mean BP (systolic/diastolic) decreased from 141 +/- 18/89 +/- 11 mm Hg to 134 +/- 19/85 +/- 13 mm Hg (p < 0.05). The reduction in 24-hour mean systolic BP occurred during both day and night, but a significant fall in mean diastolic BP was only observed during the day. The mean blood pressure fell in both normotensive and hypertensive patients. Patients who were inadequately treated with nCPAP had no reduction in mean 24-hour BP. Effective treatment of sleep apnea with nCPAP was associated with a significant fall in both systolic and diastolic BP independent of changes in body weight or alcohol consumption, suggesting that sleep apnea was an independent factor contributing to elevated nighttime and daytime BP in these patients.

Treatment of obstructive sleep apnea in achondroplasia: evaluation of sleep, breathing, and somatosensory-evoked potentials.

The occurrence of obstructive sleep apnea (OSA) is achondroplasia has been linked to brain stem compression. Overnight sleep studies (11 subjects) and somatosensory-evoked potentials (SEP's, 10 subjects) were recorded before and after conventional treatment of OSA in achondroplasia. The two groups were derived from 30 subjects who underwent diagnostic sleep studies and SEPs, including 15 females and 15 males with a median age 6.6 years (range 1.0-47.6) at the time of the first study. In 30 initial studies there was no correlation between severity of OSA and abnormalities on SEP evaluation. Treatment of 17 subjects included adenotonsillectomy (n = 3), weight loss (n = 1), and nasal-mask continuous positive airway pressure (CPAP) (n = 13). Sleep studies in 11 subjects after a delay of 8.8 +/- 2.8 months showed a reduction in respiratory disturbance index (RDI) from 38.4 +/- 6.9 to 6.5 +/- 1.8 events hr(-1) (p < 0.001) and movements/arousals fell from 10.4 +/- 2.2 to 4.8 +/- 0.2 hr(-1) (p < 0.04). Obstructive events were reduced from 33.7 +/- 6.9 to 2.4 +/- 1.0 hr(-1) (p < 0.001). Improvement of respiratory indices was associated with an increased proportion of slow-wave sleep from 25.2 +/- 4.0% to 32.3 +/- 2.4% (p = 0.01), and decrease in stage 1-2 sleep from 59.3 +/- 5.8% to 46.6 +/- 1.9% (p = 0.03). There was no increase in the percentage of REM sleep (15.2 to 21.2%). Repeat SEP studies in 10 subjects, after clinically effective treatment of OSA, showed improvement of SEP score of at least 1 grade, in 5 of 7 (71%) with initially abnormal values. We conclude that treatment of relieve upper airway obstruction improves OSA in achondroplasia, accompanied by changes in sleep structure and, in some cases, improved studies of neurological function.

Sleep apnea in Marfan's syndrome. Increased upper airway collapsibility during sleep.

Marfan's syndrome is a hereditary disorder characterized by a defect in connective tissue, resulting in tissue laxity. It is associated with a high prevalence of obstructive sleep apnea (OSA). The aim of this study was to determine whether excessive upper airway collapsibility during sleep is an important pathophysiologic factor predisposing these individuals to OSA. We measured upper airway closing pressures (UACP) during sleep in 12 patients with Marfan's syndrome and 6 age-, and height-, and weight-matched control subjects. Ten of the patients had OSA, defined as an apnea/hypopnea index > 5. All patients with Marfan's syndrome, including the two patients without OSA, demonstrated increased upper airway collapsibility during sleep, with a mean UACP of -2.5 +/- 0.5 cm H2O during slow-wave sleep (SWS). In contrast, only two control subjects demonstrated upper airway closure. However, this was at significantly higher suction pressures, with a mean UACP of -5.6 +/- 0.4 cm H2O during SWS (p < 0.005). These data suggest that patients with Marfan's syndrome have abnormally increased upper airway collapsibility during sleep. It is possible that this is related to the characteristic connective tissue defect of this disorder.

Effects of short-term NIPPV in the treatment of patients with severe obstructive sleep apnea and hypercapnia.

Although nasal continuous positive airway pressure (CPAP) is effective in the treatment of most patients with obstructive sleep apnea (OSA), there is a small group of such patients in whom rapid eye movement (REM) hypoventilation and CO2 retention persist despite the use of CPAP and supplemental oxygen. In this report we describe our experience with nocturnal nasal ventilation (nocturnal nasal positive pressure ventilation [NIPPV] in such patients and its effectiveness in reversing daytime hypercapnia. Thirteen patients, aged 28 to 69 years, with severe OSA confirmed on polysomnography, failed to respond to initial CPAP therapy. All were grossly obese (body mass index [BMI] > 35 kg.ml-1) and hypercapnic (mean PaCO2, 62 mm Hg). Nocturnal nasal ventilation was commenced using a volume-cycled ventilator, which was well tolerated in all patients. After 7 to 18 days of NIPPV, significant improvements in daytime arterial blood gas values were achieved, with a rise in arterial oxygen tension from 50 +/- 2.6 (SEM) to 66 +/- 3 mm Hg (p < 0.001) and a fall in CO2 from 62 +/- 2.5 to 46 +/- 1 mm Hg (p < 0.0001). Nine of the 13 patients were able to be established on a regimen of nasal CPAP after this period, while 3 patients required a longer period (up to 3 months) before adequate nocturnal ventilation could be maintained. In one patient, the improvements in ventilatory drive achieved with NIPPV could not be maintained on CPAP, and she was transferred on to NIPPV long term. These results indicate that effective nasal ventilation leads to an overall improvement in spontaneous ventilation and blood gas values both awake and asleep. We believe this improvement is the result of improved central ventilatory drive. Short-term NIPPV provides lasting benefits allowing the majority of such patients to resume CPAP therapy. Short-term intervention with this therapy should be considered as an interim measure in patients with severe hypercapnic OSA who fail to respond to initial CPAP therapy.

Reversal of central sleep apnea using nasal CPAP.

Based on the theory that obstructive (OSA) and central (CSA) sleep apneas share common pathophysiologic mechanisms, we attempted to treat eight patients with predominantly CSA by continuous positive airway pressure (CPAP). All patients exhibited repetitive episodes of CSA and mixed sleep apneas (MSA) in the supine position with a mean duration of 23.7 +/- 0.7 s and 34.5 +/- 1.3 s, respectively. The pattern of apnea changed when the subject lay in the lateral position. Five patients were observed to develop OSA in the lateral position with a mean duration of 27.2 +/- 1.5 s, while the other three patients snored continuously. High levels of CPAP (range 9.0 to 16.5 cm H2O) prevented all CSA and MSA and resulted in quiet breathing in all eight patients. Intermediate levels of CPAP produced firstly MSA, then purely OSA and/or continuous snoring. Low levels of nasal CPAP also prevented OSA and snoring occurring in the lateral posture in all subjects (range 2.0 to 8.3 cm H2O). Three patients are currently on home CPAP therapy for a range of four to 36 months. We conclude that upper airway collapse in the supine posture has a key role in the induction of CSA. We suggest that a reflex inhibition of respiration through activation of supraglottic mucosal receptors during passive oropharyngeal airway closure caused CSA in these patients.

Obstructive sleep apnea in infants and its management with nasal continuous positive airway pressure.

STUDY OBJECTIVES: Nasal continuous positive airway pressure (nCPAP) is the most common treatment for obstructive sleep apnea (OSA) in adults, and it has been effective in the treatment of OSA in children. We wanted to determine the effectiveness of long-term nCPAP therapy for OSA in infants. PATIENTS: Twenty-four infants who had OSA were treated with nCPAP via nose mask. These infants had clinical histories that included a family history of sudden infant death syndrome, an apparent life-threatening event, or facial and upper airway anatomic abnormalities. INTERVENTIONS: Overnight polysomnographic studies were performed to assess the severity of OSA in each infant and to determine the appropriate level of continuous positive airway pressure (CPAP). Studies were repeated to determine the progress of OSA and the continuing need for CPAP in each infant. RESULTS: nCPAP pressures between 4 and 6 cm H2O prevented obstruction and reversed sleep disturbances that were associated with OSA. Eighteen of the infants continued treatment at home from 1 month to > 4 years. CPAP therapy was discontinued in 13 infants after their OSA resolved. Five infants who have upper airway anatomic abnormalities remain on CPAP, and the pressure level required to prevent obstructive events during sleep has needed to be increased to as high as 10 cm H2O. CONCLUSIONS: nCPAP is an effective therapy for the management of OSA in infants, and it can be used effectively in the home environment. Regular follow-up is necessary, because the requirements for CPAP and pressure levels change with the infant's growth and development.

Relationship between craniofacial abnormalities and sleep-disordered breathing in Marfan's syndrome.

OBJECTIVES: To examine the prevalence and nature of craniofacial abnormalities in patients with Marfan's syndrome and to investigate the relationship between craniofacial abnormalities and obstructive sleep apnea (OSA) severity in these patients. DESIGN: Cross-sectional. SETTING: Marfan's syndrome clinic in a tertiary teaching hospital. PATIENTS: Fifteen consecutive adult patients (7 men and 8 women; mean [+/- SD] age, 34.8 +/- 13.2 years) who had Marfan's syndrome. MEASUREMENTS AND RESULTS: Apneic status was determined from standard overnight polysomnography testing. Measurements from standardized lateral cephalometric radiographs were compared to normative data. Thirteen patients had OSA, which was defined as an apnea/hypopnea index (AHI) of > 5 episodes per hour (mean AHI, 22 +/- 15 episodes per hour). A high prevalence of craniofacial abnormalities was found with significant gender differences for some of the variables. Significant abnormalities for the entire group were bimaxillary retrusion, a reduced maxillary length, an increased total anterior face height, a long lower anterior face height, an obtuse gonial angle, a steep mandibular plane, a reduced posterior nasal airway height, a reduced posterior airway space, and an increased distance from the mandibular plane to the hyoid bone. Univariate analysis revealed significant correlations among the total anterior face height, the upper anterior and posterior face heights, the mandibular length, and AHI. There was a significant correlation between the rank of the number of cephalometric abnormalities per patient and AHI in those patients with OSA. CONCLUSIONS: Craniofacial abnormalities are common in patients with Marfan's syndrome. The relationship between some cephalometric parameters and apnea severity suggests a potential role of craniofacial structure in the pathogenesis of OSA in these patients.

Aortic root dilatation in Marfan's syndrome: a contribution from obstructive sleep apnea?

We report two cases of Marfan's syndrome with coexistent obstructive sleep apnea (OSA) in which treatment with nasal continuous positive airway pressure was associated with attenuation of aortic root dilatation, a serious complication of the syndrome. We speculate that coexistent OSA promotes progressive aortic dilatation in some patients with Marfan's syndrome.