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PubMed2000

Respiratory disturbance index: an independent predictor of mortality in coronary artery disease.

Cardiovascular mortality was prospectively investigated in consecutive coronary artery disease (CAD) patients with versus without obstructive sleep apnea (OSA) during a follow-up period of 5 yr. An overnight sleep/ventilatory study was performed in patients requiring intensive care (n = 62, mean age 67.6 +/- 10.4 yr, range 44 to 86) during a stable condition (New York Heart Association [NYHA] functional class I-II) 4 to 21 mo after discharge from the hospital. OSA, defined as a respiratory disturbance index (RDI) of 10/h or more was found in 19 patients (mean RDI 17.5 +/- 8.3). Three OSA subjects who were successfully treated with continuous positive airway pressure (CPAP) during the observation period were excluded from the final analysis. There was no statistically significant difference (Fisher two-tailed exact test) between the OSA and non-OSA patient groups in terms of number of elderly subjects (age >/= 65 yr), gender, obesity (body mass index [BMI] >/= 30 kg/m(2)), smoking history, presence of hypertension, diabetes mellitus, hypercholesterolemia, or history of myocardial infarction at the study start. During the follow-up period, cardiovascular death occurred in six of 16 OSA patients (37.5%) compared with 4 (9.3%) in the non-OSA group (p = 0.018). The univariate predictors of cardiovascular mortality were RDI (p = 0.007), OSA (p = 0.014), age at baseline (p = 0.028), hypertension at baseline (p = 0.036), history of never-smoking (p = 0.031), and digoxin treatment during the follow-up period (p = 0.013). In a Cox multiple conditional regression model, RDI remained as an independent predictor of cardiovascular mortality (exp beta = 1.13, 95% confidence interval [CI] 1.05 to 1.21, two-sided p < 0.001). We conclude that untreated OSA is associated with an increased risk of cardiovascular mortality in patients with CAD. Furthermore, it appears appropriate that RDI is taken into consideration when evaluating secondary prevention models in CAD.

Adult↗

PubMed2000

Circulating nitric oxide is suppressed in obstructive sleep apnea and is reversed by nasal continuous positive airway pressure.

Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. The recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases, and we postulate that nitric oxide may be one of the mediators involved. This study investigates the levels of circulating nitric oxide (NO), measured as serum nitrites and nitrates, in the early morning in OSA subjects compared with control subjects, and the effect of overnight nasal continuous positive airway pressure (nCPAP) in OSA subjects. Thirty men with moderate to severe OSA (age = 41.9 +/- 9.0; apnea-hypopnea index, AHI = 48.0 +/- 18.1) were compared with 40 healthy men (age = 40.6 +/- 5.4; AHI = 1.4 +/- 1.2). Serum nitrite/nitrate levels were significantly lower in OSA subjects (OSA = 38.9 +/- 22.9 microM, control subjects = 63.1 +/- 47.5 microM, p = 0.015). There was significant negative correlation between serum nitrites/nitrates and the following parameters: AHI (r = -0.389, p = 0.001), oxygen desaturation time (r = -0.346, p = 0.004), and systolic blood pressure (BP) (r = -0.335, p = 0.005). Stepwise multiple linear regression with systolic or diastolic BP as the dependent variable identified serum nitrites/nitrates as the only significant correlate. Twenty-two OSA subjects had measurements of serum NO at baseline and after an overnight application nCPAP. There was significant increase in serum NO after nCPAP (baseline = 30.5 +/- 14.4 microM, after nCPAP = 81.0 +/- 82.1 microM, p = 0.01). This study demonstrates, for the first time, that circulating NO is suppressed in OSA, and this is promptly reversible with the use of nCPAP. The findings offer support for nitric oxide being one of the mediators involved in the acute hemodynamic regulation and long-term vascular remodeling in OSA.

Adult↗

PubMed1989

Morphology of the uvula in obstructive sleep apnea.

Alterations in pharyngeal structure and function are considered fundamental in the pathogenesis of obstructive sleep apnea (OSA). However, little is known about morphologic features of the pharynx in patients with OSA. We therefore studied the tissue composition of the uvula (midsagittal section) in patients with OSA, using a quantitative, morphometric point-counting technique. Uvula tissue was obtained by uvulopalatopharyngoplasty (UPPP) in 33 patients (mean number of apneas per hour of sleep = 32.7 +/- 5.2) and by autopsy in 22 normal subjects not known to have OSA. All statistical comparisons were controlled for differences caused by age and body mass index. Patients with OSA had a significantly greater percentage of muscle in the uvula (18.1 +/- 1.9% versus 9.3 +/- 2.1%, p = 0.02) than did normal subjects. A significant difference in fat content was also found (9.5 +/- 1.4% in patients versus 4.0 +/- 1.0% in normal subjects, p less than 0.02). These differences between patients with OSA and control subjects could not be accounted for by anthropometric or sex differences. The percentage of uvula fat tissue was significantly related to the frequency of apneas and hypopneas in sleep (r = 0.43, p less than 0.01). Uvula morphology in 6 nonapneic snorers undergoing UPPP was similar to that of patients with OSA. We conclude that the uvula in patients with OSA contains more muscle and fat than the uvula in control subjects, possibly contributing to pharyngeal narrowing in OSA.

Female↗

PubMed2006

Predictors of elevated nuclear factor-kappaB-dependent genes in obstructive sleep apnea syndrome.

BACKGROUND: Circulating nuclear factor-kappaB (NF-kappaB)-dependent genes, particularly tumor necrosis factor-alpha (TNF-alpha), are elevated in obstructive sleep apnea syndrome (OSAS) and likely contribute to cardiovascular disease. Furthermore, TNF-alpha is associated with excessive daytime sleepiness. We investigated the predictors of TNF-alpha and related genes in large, well-selected cohorts of subjects with OSAS and control subjects. METHODS: We performed a prospective study of 30 subjects who did not have OSAS (22 nonsleepy normal control subjects and 8 sleepy nonapneic subjects who snored), 36 subjects with mild to moderate OSAS, and 31 subjects with severe OSAS; all subjects were male. Groups were matched for age, body mass index, and other relevant variables. Subjects had no other disease and were not regularly taking medication. All had serum for TNF-alpha and related assays drawn after polysomnography. A total of 49 suitable subjects were treated with continuous positive airway pressure (CPAP); sleep studies together with serum assays were repeated 6 wk later. RESULTS: TNF-alpha levels were higher in subjects with OSAS than in subjects without OSAS (p < 0.001). In multivariate analysis, TNF-alpha was independently associated with the desaturation index (r = 0.399, p < 0.001), Epworth Sleepiness Score (r = 0.243, p = 0.005), and cholesterol (r = 0.216, p = 0.018). Furthermore, TNF-alpha levels were higher in sleepy nonapneic subjects who snored than in normal control subjects (p = 0.002) but lower than in subjects with OSAS (p = 0.03). CPAP therapy lowered TNF-alpha levels (p = 0.004). Another NF-kappaB-dependent cytokine, interleukin-8 (IL-8), showed similar differences between groups and after CPAP therapy, but a range of other mediators of inflammation, including IL-1, IL-6, IL-10, and IL-12, showed no differences. CONCLUSION: Intermittent hypoxia is the strongest predictor of TNF-alpha levels, supporting a role for inflammation in the cardiovascular pathophysiology of OSAS. Furthermore, TNF-alpha levels are independently associated with excessive daytime sleepiness.

Adult↗

PubMed2006

Pediatric sleep apnea: implications of the epidemic of childhood overweight.

Over the last 30 years, the prevalence of overweight across all pediatric age groups and ethnicities has increased substantially, with the current prevalence of overweight among adolescents estimated to be approximately 30%. Current evidence suggests that overweight is modestly associated with obstructive sleep apnea syndrome (OSAS) among young children, but strongly associated with OSAS in older children and adolescents. The rising incidence of pediatric overweight likely will impact the prevalence, presentation, and treatment of childhood OSAS. The subgroup of children who may be especially susceptible include ethnic minorities and those from households with caregivers from low socioeconomic groups. OSAS, by exposing children to recurrent intermittent hypoxemia or oxidative stress, may amplify the adverse effects of adiposity on systemic inflammation and metabolic perturbations associated with vascular disease and diabetes. When these conditions manifest early in life, they have the potential to alter physiology at critical developmental stages, or, if persistent, provide cumulative exposures that may powerfully alter long-term health profiles. An increased prevalence of overweight also may impact the response to adenotonsillectomy as a primary treatment for childhood OSAS. The high and anticipated increased prevalence of pediatric OSAS mandates assessment of optimal approaches for preventing and treating both OSAS and overweight across the pediatric age range. In this Pulmonary Perspective, the interrelationships between pediatric OSAS and overweight are reviewed, and the implications of the overweight epidemic on childhood OSAS are discussed.

Body Mass Index↗

PubMed2007

Effects of continuous positive airway pressure on cerebral vascular response to hypoxia in patients with obstructive sleep apnea.

RATIONALE: The mechanism leading to increased risk of stroke in patients with obstructive sleep apnea (OSA) is unknown. It may occur through alteration in the regulation of cerebral blood flow, reflected in part by the response of the cerebral vasculature to hypoxia. We hypothesized that the cerebrovascular response to hypoxia is reduced in patients with OSA. OBJECTIVE: To determine the cerebral blood flow response to hypoxia in patients with OSA. METHODS: The cerebral blood flow response to 20 minutes of isocapnic hypoxia was measured in eight male patients with OSA before and after 4 to 6 weeks of continuous positive airway pressure (CPAP) therapy and in 10 matched healthy control subjects. MEASUREMENTS AND MAIN RESULTS: The cerebral blood flow response to hypoxia was significantly lower in patients with OSA compared with control subjects (0.56 +/- 0.10 vs. 0.97 +/- 0.09% [mean +/- SE] change in blood flow velocity per % desaturation; p=0.007). After CPAP therapy, the cerebral blood flow response to hypoxia was similar between patients with OSA and control subjects (1.08 +/- 0.15 vs. 0.92 +/- 0.13% change in blood flow velocity per % desaturation; p=0.4). Moderately strong correlations were found between the cerebral blood flow response to hypoxia and the apnea-hypopnea index (r=-0.57; p=0.04) and nocturnal oxyhemoglobin saturation (r=0.48; p=0.01). CONCLUSIONS: The cerebral blood flow response to hypoxia is significantly reduced in patients with OSA. Treatment of OSA with CPAP increases the cerebral blood flow response to hypoxia to normal levels. An attenuated cerebrovascular response to hypoxia in patients with OSA may contribute to their elevated risk of stroke.

Adult↗

PubMed2006

Association between lipid peroxidation and inflammation in obstructive sleep apnoea.

In the present study, the authors examined the relationship between lipid peroxidation and inflammation in patients with obstructive sleep apnoea (OSA). A total of 40 obese patients with OSA were studied, along with 18 obese and 12 lean subjects without OSA. Overnight excretion of 8-isoprostane in urine and serum levels of high-sensitivity C-reactive protein (hsCRP) were measured. In addition, the effects of 3 months' treatment with nasal continuous positive airway pressure (nCPAP) were studied in 20 obese patients with moderate-to-severe OSA. Overnight urinary excretion of 8-isoprostane and serum levels of hsCRP were significantly higher in patients with moderate-to-severe OSA compared with patients with mild OSA and obese or lean subjects without OSA. Overnight urinary excretion of 8-isoprostane significantly correlated with apnoea-hypopnoea index, duration of hypoxia during sleep, body mass index, and serum levels of hsCRP in patients with OSA. The severity of OSA was an independent factor predicting the urinary excretion of 8-isoprostane. nCPAP significantly decreased urinary excretion of 8-isoprostane and serum levels of hsCRP. In conclusion, these results suggest that both obstructive sleep apnoea severity and obesity can independently contribute to elevations in urinary excretion of 8-isoprostane. Therefore, obstructive sleep apnoea may increase the risks of cardiovascular morbidity in obese patients.

C-Reactive Protein↗

PubMed1994

The cardiovascular effects of obstructive sleep apnoeas: analysis of pathogenic mechanisms.

Obstructive sleep apnoeas (OSA) exert immediate marked cardiovascular effects, and may favour the development of systemic and pulmonary hypertension in the long-term. As for the pathogenesis of the acute cardiovascular changes, the first studies high-lighted the role of OSA-induced hypoxia and mechanical changes. However, more recent work pointed to the role played by the arousal reaction terminating OSA, and to the activity of the autonomic nervous system during apnoea and inter-apnoeic phase. As for the pathogenesis of chronic cardiovascular changes, recent findings suggest that the link between OSA and systemic hypertension may be through an abnormal function of the carotid body and underline the importance of chronic intermittent hypoxia versus continuous hypoxia in the development of stable systemic hypertension. On the other hand, OSA do not appear to enhance strongly the development of stable pulmonary hypertension. In this review, we analyze OSA-induced cardiovascular changes with particular emphasis on to the interplay of the possible pathogenic mechanisms involved. Acute OSA-induced cardiovascular alterations during the apnoeic phase appear to result mainly from the mechanical effects of OSA, while during the interapnoeic phase they seem mostly determined by chemical factors (hypoxia, hypercapnia) and by the arousal reaction. In addition, the role of reflex changes elicited by resumption of ventilation should be reconsidered, since lung inflation seems to exert a positive effect on the cardiovascular changes occurring at the end of OSA. This would be in contrast with the inhibitory effects described as "lung inflation reflex", and deserves further study.

Blood Pressure↗

PubMed2002

Concomitant impairment of growth hormone secretion and peripheral sensitivity in obese patients with obstructive sleep apnea syndrome.

To clarify the impairment of the GH/IGF-I axis in obstructive sleep apnea syndrome (OSAS), in 13 adult male patients with OSAS (OSA) as well as 15 weight-matched patients with simple obesity (OB) and 10 normal lean male subjects (NS), we studied: 1) the GH response to GHRH (1 micro g/kg iv) plus arginine (30 g iv); and 2) the IGF-I and IGF binding protein-3 responses to a very low dose recombinant human (rh)GH treatment (5.0 microg/kg sc per day for 4 d). The GH response to arginine plus GHRH in OSA was lower than in OB (P < 0.05), which in turn was lower than in NS (P < 0.001). Basal IGF-I levels in OSA were lower than in OB (P < 0.05), which in turn were lower than in NS (P < 0.03). As opposed to OB and NS, in OSA a very low rhGH dose did not affect IGF-I. Adjusting for age and basal values, rhGH-induced IGF-I rise in OSA was lower than in OB (P < 0.01). IGF binding protein-3, glucose, and insulin levels in the three groups were not modified by rhGH. OSA show a more marked impairment of the maximal secretory capacity of somatotroph cells together with reduced IGF-I sensitivity to rhGH stimulation. These findings suggest that OSAS is connoted by a concomitant impairment of GH secretion and sensitivity.

Adult↗

PubMed2005

Relationships between sleep disordered breathing and glucose metabolism in polycystic ovary syndrome.

CONTEXT: Women with polycystic ovary syndrome (PCOS) are insulin resistant and are at increased risk for sleep apnea, which, in turn, may contribute to insulin resistance. OBJECTIVE: The objective of this study was to determine relationships between risk and severity of obstructive sleep apnea (OSA) and glucose metabolism in PCOS. DESIGN AND SETTING: This study included two cohorts of women with PCOS in a tertiary care hospital. PATIENTS AND MAIN OUTCOME MEASURES: Cohort 1 included 40 nondiabetics who completed the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality, and the Berlin Questionnaire to assess risk of OSA; 32 of the 40 women had an oral glucose tolerance test. Cohort 2 included eight women who had a sleep study, glycosylated hemoglobin level, and an oral glucose tolerance test. RESULTS: In cohort 1, 62.5% of the women had poor sleep quality by Pittsburgh Sleep Quality Index, and 18 (45%) had chronic daytime sleepiness by Epworth Sleepiness Scale. Thirty of the 40 women had a high risk of OSA by Berlin Questionnaire. Women with high OSA risk had higher fasting insulin levels and homeostasis model assessment index compared with those with low OSA risk (168.2 +/- 17.3 vs. 97.2 +/- 6.4 pmol/liter, P = 0.011; 6.3 +/- 0.7 vs. 3.6 +/- 0.3 mg/dl x microU/ml, P = 0.014, respectively). Among women with normal glucose tolerance, insulin levels were significantly higher in those at high vs. low OSA risk, independently of body mass index. Women in cohort 2 had rapid eye movement (REM)-predominant OSA with lower sleep efficiency, longer sleep latency, and less REM sleep than controls. Glycosylated hemoglobin levels and the area under the glucose curve positively correlated with the apnea-hypopnea index (rP = 0.82, P = 0.013; rP = 0.96, P = 0.0008, respectively) and the number of oxygen desaturations in REM sleep (rP = 0.97, P = 0.0009; rP = 0.97, P = 0.005, respectively). CONCLUSION: PCOS is associated with poor sleep quality, daytime sleepiness, and increased risk for OSA. Insulin levels and measures of glucose tolerance in PCOS are strongly correlated with the risk and severity of OSA.

Adult↗

PubMed2006

Perioperative complications of adenotonsillectomy in children with obstructive sleep apnea syndrome.

We evaluated the rate of complications experienced by children who undergo adenotonsillectomy for obstructive sleep apnea syndrome (OSAS), the safety of a standard anesthetic protocol for these children, and preoperative predictors of complications. Sixty-one children with OSAS, confirmed by polysomnography, and 21 children with recurrent tonsillitis were anesthetized using a standard protocol before adenotonsillectomy (ages 2-16 yr, ASA 1-3). The number of complications and medical interventions in the perioperative period were recorded and correlated with the presence and severity of OSAS. Children with OSAS had more respiratory complications per operation than non-OSAS children (5.7 vs 2.9, P < 0.0001). Supraglottic obstruction, breath holding, and desaturation on anesthetic induction and emergence were the most common complications. Increased severity of OSAS, low weight, and young age are correlated with an increased rate of complications. Medical intervention was necessary in more children with OSAS during recovery and emergence than in the non-OSAS group (17/61 vs 1/21, P < 0.05). Both groups of children had similar opioid requirements and time to discharge from the recovery room. These findings suggest that children with OSAS are at risk for respiratory complications after adenotonsillectomy, but that these complications do not prolong the time to discharge.

Adenoidectomy↗

PubMed2006

Concurrent presence of metabolic syndrome in obstructive sleep apnea syndrome exacerbates the cardiovascular risk: a sleep clinic cohort study.

This cross-sectional study was conducted to examine whether the obstructive sleep apnea syndrome (OSAS) is associated with elevation of the pulse wave velocity (PWV) and increase in the plasma levels of C-reactive protein (CRP), both of which are known markers of cardiovascular risk, and also to determine if the concurrent presence of the metabolic syndrome might exacerbate this elevation in the levels of these cardiovascular risk markers in subjects with OSAS. With these objectives, the PWV and serum CRP were measured in 184 subjects attending a sleep clinic. It was found that the PWV and CRP were higher in the subjects with OSAS (n=94) than in those without OSAS (n=90). Furthermore, among the subjects with OSAS, the PWV and CRP were higher in those with the concurrent presence of the metabolic syndrome (n= 41; PWV=1,562+/-19 cm/s; CRP=1.8+/-0.2 mg/l) than in those without metabolic syndrome (n=53; PWV=1,432+/-21 cm/s; CRP=1.2+/-0.1 mg/l) (p<0.05). A general linear model analysis demonstrated that OSAS and metabolic syndrome were independently associated with elevated PWV and increase of the plasma levels of CRP. OSAS appears to be associated with increased cardiovascular risk, as reflected by both elevated PWV and increase of the plasma CRP. The concurrent presence of metabolic syndrome may exacerbate this increase in cardiovascular risk in subjects with OSAS. Therefore, the concurrent presence of metabolic syndrome may constitute an additive cardiovascular risk factor in subjects with OSAS.

Adult↗

PubMed1993

24-hour ambulatory blood pressure variability in obstructive sleep apnea syndrome.

The 24-h ambulatory blood pressure (24h-ABP) was examined in 21 men, aged 38 to 65 years (mean 50.6), with obstructive sleep apnea syndrome (OSAS) and in 123 normal male control subjects, aged 40 to 60 years (mean 48.1) who did not have OSAS, obesity, autonomic nervous system abnormality, cardiac disease, or respiratory disease (group C), to assess the role of apneas in the circadian variation of blood pressure (BP). The 24h-ABP patterns in OSAS patients were classified into three types as follow: normotensive OSAS patients with normal BP throughout the 24-h period with nocturnal BP fall (type 1); hypertensive OSAS patients with progressive BP elevation from onset of sleep to early morning (type 2); and hypertensive OSAS patients with elevated BP (systolic BP > or = 140 mm Hg or diastolic BP > or = 90 mm Hg) at any time during a 24-h period (type 3). It was concluded that the circadian BP variation in type 1 was almost identical to the level and pattern of group C; the circadian variations in types 2 and 3 were significantly different from that of group C; and the patients with types 2 and 3 BP patterns had more severe OSAS than type 1 patients. The severity of OSAS was an important factor in nocturnal elevation of BP, hence affecting the circadian variation of BP. Noninvasive 24h-ABP monitoring is a useful procedure for understanding the clinical features of OSAS patients with or without hypertension.

Adult↗

PubMed1995

Spontaneous platelet activation and aggregation during obstructive sleep apnea and its response to therapy with nasal continuous positive airway pressure. A preliminary investigation.

STUDY OBJECTIVE: To determine whether alterations of platelet reactivity occur during obstructive sleep apnea (OSA) and, if so, whether therapy with nasal-continuous positive airway pressure (N-CPAP) alters this reactivity. DESIGN: Patients with suspected moderate to severe OSA had blood drawn for spontaneous platelet aggregation (sAGG) and activation (sACT) measurements at hourly intervals during diagnostic polysomnography (PSG) and, in those with confirmed OSA, on a separate night during which N-CPAP was applied. SETTING: Tertiary care center sleep laboratory. PATIENTS: Six patients with OSA had matched blood samples drawn on both diagnostic and N-CPAP treatment nights. Five patients without confirmed OSA served as controls. INTERVENTIONS: N-CPAP was applied to those patients with OSA and pressures adjusted with goals of eliminating apneas; N-CPAP was then maintained through the night. MEASUREMENTS AND RESULTS: sACT and sAGG were measured using flow cytometric determination of P-selectin expression using a monoclonal antibody. Platelet aggregation was assessed by measuring the proportion of platelets larger than resting platelets by light scatter techniques. Mean values for sACT and sAGG were higher on the diagnostic night compared with treatment night (p = 0.001 and p = 0.003, analysis of variance, respectively). The mean baseline supine sACT compared with completion supine sACT for both diagnostic and N-CPAP nights also revealed significant differences (mean = 16.6 +/- 3.5% vs 36.9 +/- 7.5%, p = 0.04; and 11.9 +/- 3% vs 39.5 +/- 9.1%, p = 0.04). Platelet activation during sleep in five subjects without OSA resembles that found in patients with OSA during N-CPAP. CONCLUSIONS: Increased platelet sACT and sAGG occur during sleep in patients with OSA. This effect is greatly reduced by N-CPAP.

Adult↗

PubMed1999

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.

Female↗

PubMed2000

Nasal continuous positive airway pressure use in children with obstructive sleep apnea younger than 2 years of age.

STUDY OBJECTIVES: To assess the efficacy of continuous positive airway pressure (CPAP) in obstructive sleep apnea (OSA) patients who are < 2 years of age. DESIGN: A retrospective chart review of 18 patients from 1992 to 1999 who had OSA confirmed by polysomnography. All patients in this study also completed a separate night of CPAP polysomnography to determine the effectiveness of CPAP in the correction of OSA. Nasal CPAP compliance data were gathered via clinical follow-up examination, telephone interview, or mailed questionnaire. SETTING: All patients were studied in the Sleep Disorders Center at Loma Linda University Children's Hospital in Loma Linda, CA. PATIENTS: All patients were < 2 years old. INTERVENTION: After OSA was confirmed by the results of technician-attended nocturnal polysomnography, separate technician-attended nocturnal CPAP polysomnography was completed. On CPAP nights, CPAP pressure was titrated to ameliorate OSA and snoring. CPAP pressure was increased by 2-cm H(2)O or 1-cm H(2)O increments. RESULTS: Data were analyzed by dependent groups t test at p < 0.05 level of significance. CPAP statistically improved respiratory parameters significantly when compared to baseline polysomnography. The following four patient subgroups emerged from the analysis: group 1 consisted of six patients who had tracheostomies prior to the CPAP trial, with two patients using CPAP as an alternative to tracheostomy; group 2 consisted of two patients who had previous unsuccessful adenostonsillectomies and who used CPAP successfully, with both having OSA resolution over time; group 3 consisted of four patients who did not tolerate CPAP on the study night; and group 4 consisted of six patients who used CPAP nightly, had OSA resolution over time, and therefore, no longer needed CPAP therapy. Thus, 10 of 18 patients used CPAP either on an interim basis for corrective therapy or as a primary treatment modality for OSA. CONCLUSIONS: These data show that children < 2 years of age can tolerate and use CPAP effectively. In several cases, CPAP treatment could be discontinued as OSA resolved over time. The reasons for this are discussed in the text.

Female↗

PubMed2001

Plasma homocysteine levels in obstructive sleep apnea: association with cardiovascular morbidity.

OBJECTIVES: Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity and mortality. Plasma levels of homocysteine are also associated with cardiovascular morbidity and mortality. We therefore investigated homocysteine and conventional cardiovascular risk factors in OSA patients with and without cardiovascular morbidity in comparison with normal control subjects and ischemic heart disease (IHD) patients without OSA. SETTING: Technion Sleep Medicine Center, Haifa, Israel. METHODS AND PARTICIPANTS: Levels of homocysteine, cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, creatinine, vitamins B(12) and B(6), and folic acid were determined in 345 participants after overnight fasting. These included OSA patients with IHD (n = 49), with hypertension (n = 61), or without any cardiovascular disease (n = 127). Two control groups were employed: IHD patients without or with low likelihood for sleep apnea (n = 35), and healthy control subjects (n = 73). RESULTS: After adjustment for age, body mass index, creatinine, and existence of diabetes mellitus, OSA patients with IHD had significantly higher homocysteine levels (14.6 +/- 6.77 micromol/L) than all other groups including the IHD-only patients. Hypertensive OSA patients had comparable homocysteine levels to IHD patients (11.80 +/- 5.28 micromol/L and 11.92 +/- 5.7 micromol/L, respectively), while patients with OSA only had comparable levels to normal control subjects (9.85 +/- 2.99 micromol/L and 9.78 +/- 3.49 micromol/L, respectively). No differences in conventional cardiovascular risk factors or in vitamin levels were found between groups. CONCLUSIONS: Patients with the combination of IHD and OSA have elevated homocysteine levels. We hypothesize that these results may be explained by endothelial dysfunction combined with excess free-radical formation in OSA patients.

Adult↗

PubMed2003

Hemostatic alterations in patients with obstructive sleep apnea and the implications for cardiovascular disease.

STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) are at increased risk for coronary artery and cerebrovascular diseases. Numerous studies suggest that a hypercoagulable state is prospectively related to atherothrombotic events. This review explores whether changes in hemostasis may constitute one biological link between OSA and vascular disease. DESIGN: Ten studies on hemostatic variables in OSA were located by electronic library search and descriptively reviewed. Work on hemostatic function with physiologic conditions similar to those found in OSA (hypoxemia and hyperactivity of the sympathetic nervous system) was considered to discuss potential molecular mechanisms of procoagulant disturbances in OSA. MEASUREMENTS AND RESULTS: The reviewed data suggest that, as compared to non-OSA control subjects, patients with OSA have elevated plasma fibrinogen levels, exaggerated platelet activity, and reduced fibrinolytic capacity. Although not consistently shown, severity of OSA (ie, apnea-hypopnea index) and plasma epinephrine were independent predictors of platelet activity, and average minimal oxygen saturation was an independent predictor of fibrinogen. In some studies, treatment with continuous positive airway pressure decreased platelet activity, plasma fibrinogen levels, and activity of clotting factor VII. CONCLUSIONS: There is some evidence for a hypercoagulable state in OSA, which might help explain the increased prevalence of vascular diseases in this population. To further confirm such a notion, future studies need to be performed on sufficiently large samples to be able to control for confounders of hemostatic activity. Prospective studies are needed to examine the association between hemostasis molecules and strong vascular end points.

Blood Platelets↗