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PubMed1994

Mechanisms of apnea termination in obstructive sleep apnea. Role of chemoreceptor and mechanoreceptor stimuli.

Previous work from our laboratory has indicated that mechanoreceptor feedback from the respiratory muscles may play an important role in arousal and apnea termination in obstructive sleep apnea (OSA). Other studies have pointed to a prominent role for chemoreceptor stimuli. We postulated that mechanoreceptor stimuli from the respiratory system are the primary determinant of apnea termination, and that chemoreceptor stimuli exert their effect indirectly through stimulation of ventilation and thus proprioceptive feedback. To test this, we measured the diaphragmatic tension-time index (TTdi) during obstructive sleep apneas in seven male subjects with severe untreated OSA. We compared the maximal TTdi values at end-apnea during administration of air, O2, and CO2. We reasoned that if mechanoreceptor stimuli mediate apnea termination, changing the degree of chemoreceptor stimulation during apneas should not alter the level of respiratory effort at end-apnea. O2 administration produced a significant increase in end-apneic arterial oxygen saturation (SaO2) and increased apnea duration. CO2 administration led to an increase in pre- and postapneic end-tidal carbon dioxide pressure (PETCO2), and tended to shorten apneas. However, the mean value for maximal end-apneic TTdi was 0.12 +/- 0.01 (SEM) during room air breathing and was unaltered by O2 (0.12 +/- 0.01) or CO2 (0.11 +/- 0.01) administration. The consistency of end-apneic TTdi values despite the varying chemical drive supports the hypothesis that apnea termination in OSA is mediated by mechanoreceptor feedback from the respiratory system, most likely from the respiratory muscles. The influence of chemoreceptor information may be mediated indirectly through an effect on ventilatory effort.

Adult↗

PubMed2002

[Relationship of changes in sleep architecture and cognitive function in patients with obstructive sleep apnea syndrome].

OBJECTIVES: To explore the relationship between sleep architecture changes and cognitive impairment in patients with obstructive sleep apnea syndrome (OSAS). METHODS: Thirty-six patients with OSAS and 18 controls were administered polysomnography and neuropsychological tests of visual regeneration, digital symbol, comprehensive memory and digital span. RESULTS: Performances on the visual regeneration test and digital symbol test in patients with OSAS were impaired significantly compared with the control group (P < 0.01). Patients' performance on the visual regeneration test was significantly associated with slow wave sleep duration (r = 0.423, P < 0.05) and that on the digital symbol test was significantly associated with REM sleep duration (r = 0.378, P < 0.05). CONCLUSIONS: Slow wave sleep and REM sleep derivation may play a role in the cognitive impairment in patients with OSAS.

Adult↗

PubMed2004

Perioperative treatment of patients with obstructive sleep apnea.

PURPOSE OF REVIEW: Obstructive sleep apnea is a common disorder. Despite reports of its role as a risk factor for postoperative morbidity and mortality, only a few investigators have examined the optimal treatment of patients during this vulnerable period. Recognition of obstructive sleep apnea during conscious sedation or in the perioperative period is important to prevent the occurrence of adverse outcomes. This review discusses the influence of sedative, anesthetic, and analgesic agents and other factors during the perioperative period on patients with obstructive sleep apnea. The aim of this article is to emphasize the importance of recognizing and appropriately treating surgical patients with obstructive sleep apnea. RECENT FINDINGS: Sedative, analgesic, and anesthetic agents used perioperatively play a major role in the development of sleep-disordered breathing during the postoperative period. Postoperative apneic episodes frequently occur even after surgery remote from the upper airway. Sleep apnea predisposes patients to a greater than normal risk for postsurgical complications. Adequate screening of patients preoperatively and initiation of continuous positive airway pressure therapy perioperatively could prevent serious complications, including hypoxemia, arrhythmias, myocardial infarction, and respiratory arrest. SUMMARY: Obstructive sleep apnea places a significant proportion of surgical patients at increased risk of perioperative complications. Obstructive sleep apnea can be induced, unmasked, or exacerbated by the effects of sedative, analgesic, and anesthetic agents regardless of the site of surgery. The role of sleep apnea as a risk factor for development of postoperative complications needs greater emphasis. Increased awareness of the risk posed by an obstructed upper airway and appropriate management are important to optimize the perioperative care of patients with obstructive sleep apnea.

Analgesics↗

PubMed2005

Cluster headache with obstructive sleep apnea and periodic limb movements during sleep: a case report.

We report the case of a man with episodic cluster headache who suffered from severe obstructive sleep apnea (OSA) as well as periodic limb movements during sleep (PLMS). His attacks of headache occurred primarily during sleep being timely to REM sleep as 90 to 120 minutes interval. OSAs were more frequent and prolonged during REM sleep and oxygen saturation decreased to 81% during this sleep period. Periodic limb movements were also observed in our patient that were more frequent during the first half of the polysomnographic recordings. This case is one of the few reporting cases with CH who had both OSA and PLMS.

Adult↗

PubMed2006

Increased myocardial vulnerability and autonomic nervous system imbalance in obstructive sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is characterized by the repeated episodes of upper airway obstruction during sleep, leading to significant hypoxia. Noninvasive evaluation of autonomic nervous system (ANS) and myocardial vulnerability may help determination of OSAS patients who are under high risk of malignant cardiac arrhythmias. The aim of this study was to show the effects of OSAS on predictors of arrhythmias by the evaluation of heart rate turbulence (HRT), heart rate variability (HRV) and QT dynamicity reflecting the ANS balance and myocardial vulnerability. METHODS: After polysomnographic study, 80 patients with OSAS and 55 age matched OSAS (-) subjects were included in the study. Twenty-four-hour Holter monitoring was performed in all subjects. HRT, HRV and QT dynamicity parameters were calculated. RESULTS: Turbulence slope was significantly decreased in OSAS patients whereas turbulence onset was increased (P<0.001). QT/RR slopes were significantly increased for QT end and QT apex (P<0.001). In HRV analysis, autonomic balance changed in favor of sympathetic system at night in OSAS patients. Furthermore, HRT and QT dynamicity parameters are found to be correlated with Apnea-Hypopnea Index (AHI). CONCLUSION: OSAS is associated with a significant worsening in HRV, HRT, and QT dynamicity parameters. Our results may indicate that HRV and QT dynamicity parameters can be useful noninvasive methods that may detect autonomic nervous system activity and ventricular vulnerability in OSAS.

Aged↗

PubMed2002

A randomized controlled trial of continuous positive airway pressure in mild obstructive sleep apnea.

A common clinical dilemma faced by sleep physicians is in deciding the level of severity at which patients with obstructive sleep apnea (OSA) should be treated. There is particular uncertainty about the need for, and the effectiveness of, treatment in mild cases. To help define the role of nasal continuous positive airway pressure (CPAP) treatment in mild OSA we undertook a randomized controlled cross-over trial of CPAP in patients with an apnea- hypopnea index (AHI) of 5 - 30 (mean, 12.9 +/- 6.3 SD). Twenty-four-hour blood pressure and neurobehavioral function were measured at baseline, after 8 wk of treatment with CPAP, and after 8 wk of treatment with an oral placebo tablet. Twenty-eight of 42 patients enrolled in the study completed both treatment arms. Baseline characteristics were not different between those who completed the study and those who did not complete the study. Patients used CPAP for a mean (SD) of 3.53 (2.13) h per night and the mean AHI on the night of CPAP implementation was 4.24 (2.9). Nasal CPAP improved self-reported symptoms of OSA, including snoring, restless sleep, daytime sleepiness, and irritability (in-house questionnaire), more than did placebo, but did not improve objective (Multiple Sleep Latency Test) or subjective (Epworth Sleepiness Scale) measures of daytime sleepiness. We found no benefit of CPAP over placebo in any tests of neurobehavioral function, generic SF-36 (36-item Short Form Medical Outcomes Survey) or sleep-specific (Functional Outcomes of Sleep Questionnaire) quality of life questionnaires, mood score (Profile of Moods States and Beck Depression Index), or 24-h blood pressure. However, the placebo tablet resulted in a significant improvement in a wide range of functional variables compared with baseline. This placebo effect may account for some of the treatment responses to CPAP observed previously in patients with mild OSA.

Adult↗

PubMed1998

[Breathing control of patients with obstructive sleep apnea syndrome (OSAS) during sleep].

OBJECTIVE: It is assumed that reduced ventilatory control function during sleep may be one of the mechanisms resulting in obstructive sleep apnea syndrome (OSAS), but the breathing drive has never been measured in patients with OSAS during sleep. METHOD: P0.1, delta P0.1/delta SaO2, delta VE/delta SaO2, delta P0.1/delta PaCO2 and delta VE/delta PaCO2 in sixteen patients with severe OSAS were measured via nasopharyngeal tubes connected with nasal mask to maintain upper airway patent, during wake and NREM I + II, NREM III + IV, REM sleep stages, and the same parameters in eleven normal subjects, non-snorers were also measured, by nasal mask as control. RESULT: (1) During wake: P0.1 in all the OSAS patients was remarkably higher than that of the normal subjects (P < 0.05), but there was no difference in delta VE/delta SaO2, delta P0.1/delta SaO2, delta VE/delta PaCO2 and delta P0.1/delta PaCO2 between the two groups (P > 0.05). (2) The above parameters measured during sleep compared with that measured during wake: In NREM I + II and NREM III + IV, normal subjects showed no significant decrease in P0.1, delta P0.1/delta SaO2, delta P0.1/delta PaCO2 (P > 0.05), but delta VE/delta SaO2 and delta VE/delta PaCO2 decreased significantly (P < 0.05). In REM1 P0.1 maintained the same level as that during wake, but both hypoxic and hypercapnic responses decreased remarkably (P < 0.05). In the OSAS patients, P0.1 decreased during NREM I + II and REM sleep (P < 0.5), but not during NREM III + IV (P > 0.05). delta VE/delta SaO2, delta P0.1/delta SaO2, delta P0.1/delta PaCO2 and delta VE/delta PaCO2 decreased markedly during all sleep stages (P < 0.01). (3) From wake to sleep, delta VE/delta SaO2 decreased by 51.6 +/- 30.4% (Mean +/- SD) in the OSAS patients vs 33.6 +/- 26.0% decreased in the normal subjects; delta VE/delta PaCO2 decreased by 56.9 +/- 25.5% in OSAS vs 40.8 +/- 17.5% in the normal subjects; The hypoxic and hypercapnic responses in OSAS patients decreased much more than those in the normal subjects during sleep (P < 0.05). CONCLUSION: This is the first study to measure the hypoxic and hypercapnic responses successfully in OSAS patients during sleep. It was found that the breathing drive was significantly reduced in sleeping OSAS patients, which may play an important role in the development of OSAS, possibly through the reduced action upon the dilators causing the upper airway in predilection for collapse.

Adult↗

PubMed2006

Left ventricular structural adaptations to obstructive sleep apnea in dilated cardiomyopathy.

RATIONALE AND OBJECTIVES: Obstructive sleep apnea is common among patients with heart failure and exposes the left ventricle to trophic mechanical and adrenergic stimuli. We hypothesized that in heart failure patients with nonischemic dilated cardiomyopathy (a condition characterized by eccentric hypertrophy), those with obstructive sleep apnea would have a higher prevalence of left ventricular hypertrophy by wall thickness criteria (> or = 12 mm), and greater septal thickness than those without obstructive sleep apnea. METHODS AND RESULTS: We performed echocardiography and polysomnography in 47 patients with nonischemic dilated cardiomyopathy. Obstructive sleep apnea was present in 45% of these patients. The prevalence of left ventricular hypertrophy was greater in those with than in those without obstructive sleep apnea (47.6 vs. 15.4%, p = 0.016). Interventricular septal thickness (p < 0.001) and relative wall thickness (p = 0.011) were significantly greater in those with than in those without obstructive sleep apnea. However, there was no significant difference in posterior wall thickness between the groups. The frequency of obstructive apneas and hypopneas during sleep was the only significant independent correlate of septal thickness (p = 0.001). CONCLUSIONS: In patients with nonischemic dilated cardiomyopathy, the presence of obstructive sleep apnea is associated with an increased prevalence of left ventricular hypertrophy. The higher relative wall thickness and interventricular septal thickness in patients with obstructive sleep apnea indicate that the left ventricle is relatively less eccentric than in patients without obstructive sleep apnea, and that such remodeling affects mainly the septum. These structural adaptations may reflect unique nocturnal mechanical and adrenergic stimuli associated with obstructive sleep apnea.

Adaptation, Physiological↗

PubMed2003

Haptoglobin polymorphism is a risk factor for cardiovascular disease in patients with obstructive sleep apnea syndrome.

STUDY OBJECTIVES: Obstructive sleep apnea syndrome is associated with a marked increase in the risk for cardiovascular disease. Increased oxidative stress and leukocyte adhesiveness have been implicated as fundamental pathophysiologic mechanisms underlying the increased susceptibility in these patients. Haptoglobin is an antioxidant and immunomodulatory protein encoded by 2 alleles with profoundly different biophysical and biochemical properties. We therefore sought to determine if the haptoglobin phenotype was a determinant of cardiovascular disease in patients with obstructive sleep apnea syndrome. DESIGN: Haptoglobin phenotype was determined by gel electrophoresis in 465 patients with and 757 individuals without obstructive sleep apnea syndrome. SETTING: Eight-bed Technion Sleep Medicine Center in Haifa, serving the northern part of Israel. PARTICIPANTS: Patients referred for sleep recordings because of suspected breathing disorders in sleep and healthy industry workers. MEASUREMENTS AND RESULTS: Patients with obstructive sleep apnea syndrome and cardiovascular disease had a significantly different distribution of the 3 haptoglobin phenotypes as compared to patients with obstructive sleep apnea syndrome but without cardiovascular disease. No difference in the haptoglobin phenotype frequency was found between controls with and without cardiovascular disease. Log linear analysis revealed a significant interaction effect of haptoglobin phenotype and the presence of sleep apnea on the presence of cardiovascular disease. Logistic regression analysis revealed that the risk of cardiovascular disease in sleep apnea patients younger than 55 years with haptoglobin 2-2 was 2.32-fold higher than in their counterparts with haptoglobin 2-1. CONCLUSIONS: These results suggest that haptoglobin phenotype is an important risk factor in determining susceptibility to cardiovascular disease in obstructive sleep apnea syndrome, which may be mediated by the decreased antioxidant and antiinflammatory actions of the haptoglobin 2 allelic protein product.

Alleles↗

PubMed2000

[Epworth drowsiness scale value in obstructive sleep apnea syndrome].

Hypersomnia is one of the most consulted symptoms among patients evaluated at sleep disorder centers and it is frequently related to obstructive sleep apnea syndrome (OSAS). Our hypothesis is that Epworth sleepiness scale (ESS) is the parameter with the greatest predictive value in the OSAS diagnosis. We compared patients with OSAS diagnosis to a control group. In both groups we compared ESS with body mass index (BMI), neck circumference (NC), waist perimeter (WP). Anthropometric index (BMI, NC and WC), were similar in both groups (p < 0.10). When we analyzed ESS, a score greater than 10 was observed in the OSAS group, with a significant difference between groups (p < 0.001). Epworth sleepiness scale yielded 60% of sensibility, 82% of specificity and a positive predictive value of 85%. The negative predictive value was 52%. Confidence index was 70%. The relationship between OSAS and ESS scale was significant (Pearson Chi-Square value 7.5). Odds Ratio for apneas was 15 and its confidence interval was lower than 1.5 and upper than 141. We conclude that with ESS score exceeding 10 points OSAS should be suspected.

Adult↗

PubMed2002

Assessment of closed-loop ventilatory stability in obstructive sleep apnea.

Previous studies on ventilatory control in obstructive sleep apnea (OSA) have generally indicated depressed chemosensitivity, implying greater stability of the chemical control of breathing in these subjects. However, these results were based on tests involving steady-state or quasi-steady measurements obtained in wakefulness. We have developed a method for assessing the dynamic stability characteristics of chemoreflex control in OSA patients during sleep. While continuous positive airway pressure was applied to stabilize the upper airways, acoustically stimulated arousals were used to perturb the respiratory system during sleep. The fluctuations in esophageal pressure that ensued were analyzed, using a closed-loop minimal model, to estimate the chemoreflex loop impulse response (CLIR). Tests using simulated data confirmed the validity of our estimation algorithm. Application of the method to arousal responses measured in six OSA and five normal subjects revealed no statistically significant differences in gain margins and loop gain magnitudes between the two groups. However, the CLIR in the OSA subjects exhibited faster and more oscillatory dynamics. This result implies that, in addition to unstable upper airway mechanics, an underdamped chemoreflex control system may be another important factor that promotes the occurrence of periodic obstructive apneas during sleep.

Arousal↗

PubMed1995

[Effects of nasal continuous positive airway pressure on lung function in patients with sleep obstructive apnea syndrome].

Sixty-one patients with obstructive sleep apnea syndrome (OSAS), 26 of whom also had chronic obstructive pulmonary disease (COPD), received treatment by nasal continuous positive airways pressure (nCPAP). To evaluate the effects of this device on daytime lung function, we analyzed pulmonary function tests before treatment with nCPAP and after a mean follow-up period of 12 months (range: 2-22 months). In patients with both OSAS and COPD, we observed a significant decrease in PaCO2 (p < 0.007), in airways resistance (p < 0.002) and in residual volume (p < 0.01); for these same patients we recorded increases in forced vital capacity (p < 0.04) and maximum inspiratory pressure (p < 0.02). We saw no change in lung function in patients with OSAS only. PaO2 increased after treatment in the 15 patients who were initially hypoxemic (p < 0.001). We conclude that after treatment with nCPAP, the greatest changes in respiratory function occur in patients with both OSAS and COPD, who also experience slight decrease in body weight. These changes may be explained by a decrease in auto-PEEP and weight loss.

Adult↗

PubMed2006

Twenty-four-hour ambulatory BP in snoring children with obstructive sleep apnea syndrome.

INTRODUCTION: Obstructive sleep apnea syndrome (OSAS) is a known risk factor for hypertension in adults. This relationship is less clear in childhood OSAS. OBJECTIVE: This study examined the relationship between OSAS and 24-h ambulatory BP (ABP), a more accurate assessment than casual BP, in children with snoring. METHODS: Snoring children aged 6 to 15 years who underwent polysomnography in the sleep laboratory were recruited. MEASUREMENT: Twenty-four-hour ABP monitoring was initiated a few hours before polysomnography. The children were classified into two groups: a high apnea-hypopnea index (AHI) group (obstructive AHI > 5/h), and a low-AHI group (AHI < or = 5/h). Mean sleep, wake, and 24-h systolic BP (SBP) and diastolic BP (DBP) were recorded. A child was considered a "nondipper" if his or her mean SBP and DBP did not decrease by >/= 10% during sleep. RESULTS: Ninety-six children (mean age +/- SD, 9.4 +/- 2.8 years) were recruited. Forty-one children were obese. When awake, the high-AHI group children had a significantly higher SBP. When asleep, both SBP and DBP were higher in the high-AHI group. Age, body mass index (BMI) z score, and desaturation index (DI) were significant predictors for elevated sleep DBP. BMI z score was the only significant predictor for wake and sleep SBP. Sixteen children (17%) had hypertension, and all were nondippers. Obese children in the high-AHI group had a significantly higher prevalence of hypertension than obese children in the low-AHI group. This relationship was not found in nonobese children. CONCLUSION: The current study shows that increased DI contributed to the elevation of sleep DBP elevation.

Blood Pressure↗

PubMed2000

Diagnosing and comanaging patients with obstructive sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea syndrome, or OSAS, is a common, but underdiagnosed, disorder that potentially is fatal. It is characterized by repetitive episodes of complete or partial upper airway obstruction leading to absent or diminished airflow into the lungs. These episodes usually last 10 to 30 seconds and result in loud snoring, a decrease in oxygen saturation, and chronic daytime sleepiness and fatigue. The obstruction is caused by the soft palate, base of the tongue or both collapsing against the pharyngeal walls because of decreased muscle tone during sleep. Potentially fatal systemic illnesses frequently associated with this disorder include hypertension, pulmonary hypertension, heart failure, nocturnal cardiac dysrhythmias, myocardial infarction and ischemic stroke. CLINICAL IMPLICATIONS: The classic signs and symptoms of OSAS may be recognizable by dental practitioners. Common findings in the medical history include daytime sleepiness, snoring, hypertension and type 2 diabetes mellitus. Common clinical findings include obesity; a thick neck; excessive fat deposition in the palate, tongue (enlarged) and pharynx; a long soft palate; a retrognathic mandible; and calcified carotid artery atheromas on panoramic and lateral cephalometric radiographs. CONCLUSIONS: Dentists cognizant of these signs and symptoms have an opportunity to diagnose patients with occult OSAS. After confirmation of the diagnosis by a physician, dentists can participate in management of the disorder by fabricating mandibular advancement appliances and performing surgical procedures that prevent recurrent airway obstruction.

Humans↗

PubMed2004

Neurobehavioral functioning in obstructive sleep apnea: differential effects of sleep quality, hypoxemia and subjective sleepiness.

This study evaluated the relationship between neuropsychological and affective functioning, subjective sleepiness and sleep-disordered breathing in 100 patients with obstructive sleep apnea (OSA). Using principal components analysis, three indices of sleep-disordered breathing were identified from polysomnography: sleep disturbance, extent of nocturnal hypoxemia, and sleep quality. Poorer sleep quality was related to slower processing speed, somatic symptomatology and tension-anxiety levels. Nocturnal hypoxemia was related to visuconstructional abilities, processing speed and mental flexibility. Patients who had high levels of subjective sleepiness had poorer performances on a complex task of executive functioning and higher levels of tension-anxiety. These results imply a differential effect of sleep-disordered breathing on domains of neuropsychological functioning. Additionally, they suggest that a patient's subjective level of sleepiness is a good predictor of certain aspects of neurobehavioral functioning.

Adult↗

PubMed2004

Obstructive sleep apnea and cardiovascular disease.

Obstructive sleep apnea (OSA) is a common medical condition that occurs in approximately 5% to 15% of the population. The pathophysiology of OSA is characterized by repetitive occlusions of the posterior pharynx during sleep that obstruct the airway, followed by oxyhemoglobin desaturation, persistent inspiratory efforts against the occluded airway, and termination by arousal from sleep. Obstructive sleep apnea is associated with daytime sleepiness and fatigue, likely due to fragmented sleep from recurrent arousals. Substantial evidence shows that patients with OSA have an increased incidence of hypertension compared with individuals without OSA and that OSA is a risk factor for the development of hypertension. Recent studies show that OSA may be implicated in stroke and transient ischemic attacks. Obstructive sleep apnea appears to be associated with coronary heart disease, heart failure, and cardiac arrhythmias. Pulmonary hypertension may be associated with OSA, especially in patients with preexisting pulmonary disease. Although the exact cause that links OSA with cardiovascular disease is unknown, there is evidence that OSA is associated with a group of proinflammatory and prothrombotic factors that have been identified to be important in the development of atherosclerosis. Obstructive sleep apnea is associated with increased daytime and nocturnal sympathetic activity. Autonomic abnormalities seen in patients with OSA include increased resting heart rate, decreased R-R interval variability, and increased blood pressure variability. Both atherosclerosis and OSA are associated with endothelial dysfunction, increased C-reactive protein, interleukin 6, fibrinogen, and plasminogen activator inhibitor, and reduced fibrinolytic activity. Obstructive sleep apnea has been associated with enhanced platelet activity and aggregation. Leukocyte adhesion and accumulation on endothelial cells are common in both OSA and atherosclerosis. Clinicians should be aware that OSA may be a risk factor for the development of cardiovascular disease.

Arousal↗

PubMed2002

Sleep structure correlates of continuous positive airway pressure variations during application of an autotitrating continuous positive airway pressure machine in patients with obstructive sleep apnea syndrome.

STUDY OBJECTIVES: To evaluate the relationship between sleep structure and continuous positive airway pressure (CPAP) delivered by an automatic CPAP (auto-CPAP) machine in patients with obstructive sleep apnea syndrome (OSAS). DESIGN: Nocturnal polysomnography was performed during CPAP administration by an auto-CPAP machine (Autoset Clinical 1; ResMed; Sydney, Australia). SETTING: Sleep-disorders center in a research institute. PATIENTS: Fifteen subjects with newly diagnosed OSAS deserving home CPAP treatment. MEASUREMENTS AND RESULTS: During the night, in most cases, the lowest CPAP level was recorded during a prolonged nonrapid eye movement (NREM) sleep period uninterrupted by arousals, whereas the highest level during wake-sleep transitions or NREM sleep fragmented by arousals. In four subjects, rapid eye movement sleep was always associated with increasing CPAP. Sleep efficiency was negatively correlated with CPAP variability, evaluated as the SD of the mean nocturnal CPAP level averaged epoch by epoch (r = 0.63, p < 0.02). Eighty-eight percent of rapid CPAP augmentations (increases by at least 2 cm H(2)O in less-than-or-equal 2 min) were observed during sleep-wake transitions or after arousals/awakenings (Ar/Aw); 63% of such Ar/Aw were not preceded by any detectable respiratory abnormality. CONCLUSIONS: CPAP levels and variations during auto-CPAP application may be mainly related to sleep continuity and efficiency. The recording of a highly variable pressure during auto-CPAP administration in an unattended environment must raise the question whether the patient's sleep quality was acceptable. A poor sleep quality during an autotitration night could lead to an undesirable overestimation of the CPAP level needed for use with fixed-level CPAP machines.

Adult↗

PubMed1999

[Effects of sleep stage on blood pressure and heart rate in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To determine the effects of sleep stage on blood pressure(BP) and heart rate(HR) and to explore the relationship between BP and HR in patients with obstructive sleep apnea syndrome (OSAS). METHODS: Manometric tube was retained in the radial artery, and whole-night polysomnography (PSG) was done synchronously in 13 patients with OSAS. RESULTS: (1) The increase in BP during apnea was higher in REM sleep than in NREM sleep, but the difference was not significant (P > 0.05). When BP in awake state was regared as baseline, the increases in SBP pre-apnea and post-apnea and the increases in DBP post-apnea were significantly higher in REM sleep(-1.9 +/- 11.9 mm Hg, 32.6 +/- 20.6 mm Hg, 18.2 +/- 11.6 mm Hg, respectively) than in NREM sleep (-8.4 +/- 8.0 mm Hg, 20.4 +/- 6.9 mm Hg, 13.2 +/- 5.8 mm Hg, P < 0.05, respectively). (2) In different sleep stages, HR was markedly higher at the end of apnea than before apnea(NREM: 76 +/- 8 bpm vs 70 +/- 8 bpm, P < 0.05; REM: 85 +/- 11 bpm vs 71 +/- 8 bpm, P < 0.01). HR in post-apnea (P < 0.01) and the increase in HR during apnea (NREM: 6.9 +/- 2.2 bpm, REM: 14.1 +/- 10.1 bpm, P < 0.05) were remarkably higher in REM sleep than in NREM sleep, but not for pre-apneic HR. (3) In NREM sleep, HR in pre-apnea was significantly correlated with the increase in SBP and DBP during apnea(r = -0.699, P < 0.01; r = -0.602, P < 0.05, respectively); The increase in SBP during apnea in NREM sleep was also correlated with post-apnea HR (r = -0.669, P < 0.01). CONCLUSION: Sleep stage has effects on BP and HR and the changes in BP are correlated with the changes in HR during apnea in patients with OSAS.

Adult↗