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PubMedDate not supplied

The behavioral morbidity of obstructive sleep apnea.

The behavioral morbidity associated with obstructive sleep apnea (OSA) includes symptoms of excessive daytime sleepiness (EDS), neurocognitive deficits, psychological problems, and possibly an increased chance of accidents. EDS is among the most frequently reported symptoms in patients diagnosed with OSA. The available data suggest that the primary cause of EDS is sleep fragmentation. The subjective measures of sleepiness include the sleep wake activity inventory and the epworth sleepiness scale. Sleepiness can also be evaluated objectively in the sleep laboratory using the multiple sleep latency test or the maintenance of wakefulness test. The neurocognitive manifestations of OSA include impairments in vigilance, concentration, memory, and executive function. There is no agreed on consensus as to how to best quantify neurocognitive deficits in this population. Symptoms consistent with depression or personality changes have also been described, but are likely to be correlates of EDS and/or the chronicity of the disorder. Manifestations of the behavioral morbidity of OSA are reversible, but dependent on the degree of normalization in sleep-disordered breathing and the individual's sleep habits.

Accidents, Traffic↗
PubMed1984

Upper airway closing pressures in obstructive sleep apnea.

We studied 18 patients with obstructive sleep apnea (OSA). Each subject slept while breathing through the nose with a specially designed valveless breathing circuit. Low levels of continuous positive airway pressure (CPAP) applied through the nose (2.5-15.0 cmH2O) prevented OSA and allowed long periods of stable stage III/IV sleep and rapid-eye-movement (REM) sleep. Externally applied complete nasal occlusion while the upper airway was patent resulted in upper airway closure during inspiration which was identified by a sudden deviation of nasal pressure from tracheal or esophageal pressure. The level of upper airway closing pressure (UACP) did not change throughout the occlusion test, suggesting that upper airway dilator muscles do not respond to asphyxia during sleep. The upper airway was more collapsible during stage I/II non-rapid-eye-movement (NREM) and REM sleep compared with stage III/IV NREM sleep. The pooled mean UACP was 3.1 +/- 0.4 cmH2O in stage I/II NREM, 4.2 +/- 0.2 cmH2O in stage III/IV NREM, and 2.4 +/- 0.2 cmH2O in REM sleep. Nasal occlusion at successively higher levels of CPAP did not alter the level of UACP in stage I/II NREM and REM sleep but resulted in the upper airway becoming more stable in stage III/IV NREM sleep, suggesting a reflex which augments the tone of upper airway dilator muscles.

Adult↗
PubMed1990

Long-term effects of treatment with nasal continuous positive airway pressure on daytime lung function and pulmonary hemodynamics in patients with obstructive sleep apnea.

Fifty-four patients with obstructive sleep apnea (OSA) syndrome received long-term treatment with nasal continuous positive airway pressure (CPAP). The effects on daytime lung function and pulmonary hemodynamics were prospectively evaluated by repeating pulmonary function tests, including right heart catheterization after a follow-up period of at least 1 yr (554 +/- 28 days, mean +/- SEM). PaO2 increased in the patient group as a whole from 69.9 +/- 1.4 to 72.8 +/- 1.4 mm Hg (p less than 0.02). The increase in PaO2 was greater (from 60.4 +/- 1.0 to 66.4 +/- 2.1, p less than 0.01) in those patients who were hypoxemic prior to treatment. PaCO2 decreased significantly only in the subgroup of patients with significant hypercapnia prior to treatment (n = 7), from 48.5 +/- 1.3 to 44.5 +/- 1.5 mm Hg (p less than 0.01). The improvement in daytime blood gases seemed to be related to an increase in the alveolar ventilation, from 5.2 +/- 0.2 to 5.9 +/- 0.3 L/min without a change in the alveolar-arterial PO2 difference, as calculated in 25 patients. Both the red blood cell count and the hematocrit decreased significantly, from 5,347 +/- 90 to 5,024 +/- 61 10(3)/mm3 and from 49.4 +/- 0.9 to 47.1 +/- 0.6%, p less than 0.001 and p less than 0.02, respectively. No change was observed in the resting pulmonary arterial pressure. We conclude that nasal CPAP is effective in improving daytime blood gases in patients with OSA.

Blood Pressure↗
PubMed1992

The effects of transcutaneous electrical stimulation during wakefulness and sleep in patients with obstructive sleep apnea.

Upper airway (UA) collapse in obstructive sleep apnea (OSA) is considered in part to result from the decrease in UA dilator muscle tone that occurs during sleep. We hypothesized that augmentation of UA muscle function by transcutaneous electrical stimulation (TES) might function to enlarge UA size during wakefulness and/or prevent UA collapse during sleep in patients with OSA. Eight male patients with OSA were studied both awake and asleep, with TES administered to the submental region in two patients and to both the submental and subhyoid regions in six patients. Fast-CT scans obtained at FRC and end-inspiration (VTei) demonstrated increased UA size with tidal breathing, p less than or equal to 0.05. The active generation of -10 cm H2O pressure at FRC substantially decreased UA size, p less than or equal to 0.001. However, no changes in UA size were detected at either FRC or VTei with TES applied at 50 and 100% of the maximal tolerated intensity. The collapsibility of the UA in response to the generation of -10 cm H2O pressure was also unchanged by TES. In contrast to the lack of effect of TES on UA size, voluntary protrusion of the tongue increased cross-sectional area (CSA) of the orohypopharyngeal (OHP) segment of the UA, p less than 0.05, and to a lesser extent the CSA of the distal velopharyngeal segment, p = 0.06. When applied during sleep, TES failed to prevent or improve either sleep-disordered breathing or sleep architecture.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1984

Upper airway morphology in patients with idiopathic obstructive sleep apnea.

Fundamental to the pathogenesis of obstructive sleep apnea (OSA) is the interaction of physiologic and anatomic alterations of the upper airway. However, many patients with OSA have no identifiable abnormality of the upper airway, and they have been termed idiopathic. In an attempt to find a structural deviation in upper airway anatomy, we performed acoustic echography and cephalometric roentgenograms in 9 male patients with OSA and no clinical evidence of upper airway abnormality. Mean cross-sectional area of the pharynx by acoustic reflection was less in these patients (3.7 +/- 0.8 cm2) than in subjects in a control group (5.3 +/- 0.6 cm2) (p less than 0.001). Mean glottic cross-sectional area was less in the patient group (1.5 +/- 0.5 cm2) than in the control group (2.7 +/- 0.5) (p less than 0.001). There was a significant correlation between the number of apneas per sleep hour and pharyngeal cross-sectional area (r = 0.87, p less than 0.01). Cephalometric analysis indicated that the patients had smaller mandibles by a mean of 5.4 +/- 6.6 mm (p less than 0.05). The overall posterior displacement of the mandibular symphysis, which is representative of the skeletal support of the anterior pharyngeal wall and is dependent on both mandibular size and position, was highly significant (6.4 +/- 4.7 mm) (p less than 0.01). Furthermore, there was a significant correlation between the number of apnea episodes per sleep hour and the total posterior displacement (r = 0.67, p less than 0.05). This study indicates that patients with so-called idiopathic OSA may have an anatomic predisposition to the development of upper airway occlusion that may not be detectable on clinical examination.

Adult↗
PubMed1986

Diaphragmatic responses to body position changes in obese patients with obstructive sleep apnea.

Patients with severe obesity and obstructive sleep apnea (OSA) have been shown to have abnormalities in respiratory muscle function and respiratory control. The present study was done to evaluate diaphragmatic function and the diaphragm fiber-length-compensating reflex in morbidly obese patients with OSA (1). Twelve normal subjects and 13 morbidly obese patients with OSA were studied in recumbent and upright positions. In the normal subjects, the diaphragm fiber-length-compensating reflex operated normally causing the diaphragm's inspiratory EMG to increase when the diaphragm's fibers shortened with assumption of the upright position. However, 8 of the 13 obese patients with OSA showed a decrease rather than an increase in the inspiratory diaphragmatic EMG on assuming the upright posture. Further data indicate greater diaphragmatic efficiency in the upright than in the supine position in a majority of the obese patients, a reversal of the normal response. Two possible explanations of these observations are: an abnormality of central respiratory control in obese patients with OSA and overstretching of the diaphragm in the recumbent obese patient. The observation of reduced maximal transdiaphragmatic pressures in the recumbent position in some of the obese patients with OSA supports the second explanation. Diaphragmatic overstretching may be an important mechanism in the development of hypoventilation in the morbidly obese.

Adult↗
PubMed1986

Maxillary, mandibular, and hyoid advancement: an alternative to tracheostomy in obstructive sleep apnea syndrome.

Nine patients with severe obstructive sleep apnea syndrome (OSAS)--for whom several therapeutic approaches, including palatopharyngoplasty, had failed--were treated with a combined maxillary, mandibular, and hyoid advancement. Objective evaluation--performed before and 4 to 18 months after surgery, using nocturnal polysomography--indicated that the OSAS had improved or had disappeared. This surgical approach is beneficial for specific cases of OSAS, which can be identified by mandatory presurgical tests.

Female↗
PubMed1999

Technologic advances in the treatment of obstructive sleep apnea syndrome.

Among adult patients with obstructive sleep apnea syndrome (OSAS), adherence to continuous positive airway pressure (CPAP) treatment is approximately 40%, according to recent well-designed studies that evaluated outcomes other than adherence as a primary end point. This finding suggests the need for the improvement of the adult OSAS treatment approach, either by improving adherence to CPAP treatment or by developing effective alternatives to CPAP. Technologic advances have allowed for the development of new treatments for OSAS that include automatic CPAP and innovative airway procedures. Studies evaluating the application of these new technologies are reviewed. These technologic advances can be viewed as possible improvements over the existing treatment approach only if the risks and benefits of each new treatment are well understood by OSAS patients and their physicians.

Adult↗
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↗
PubMed1999

Treatment of obstructive sleep apnea.

Options for the treatment of obstructive sleep apnea are varied and ever-expanding. This article reviews the currently available treatment modalities in an evidence-based format. Focus is placed on the efficacy and limitations of each particular therapy.

Humans↗
PubMed1991

[Obstructive sleep apnea syndrome: the orthodontist's viewpoint].

Obstructive sleep apnea syndrome (OSAS), previously called Pickwickian syndrome is usually associated with obesity, excessive daytime sleepiness and ventilation troubles. These patients are heavy snorers and present a typical craniofacial morphology. Among several characteristics is retrognathic lower maxillary. Functional orthodontic appliances are proposed to help these patients, in order to open the superior airway and allow a better ventilation.

Facial Bones↗
PubMed1996

[Sex-specific sleep anamnesis in obstructive sleep apnea syndrome?].

Although the prevalence of obstructive sleep apnea syndrome (OSAS) is about 4% in men and 2% in women, women are underrepresented in clinical routine. The aim of this study was to determine whether differences in clinical features of OSAS may in part explain the bias observed. 224 men and 24 women with polysomnographically confirmed OSAS filled in a symptom-focussed multiple-choice questionnaire. Polysomnographical results were comparable in both groups. With regard to snoring, daytime sleepiness and tendency of falling asleep there were no differences between both groups. Women more frequently complained about difficulties of initiating and maintaining sleep and about apneas. Further investigations have to concentrate on the pathomechanisms of OSAS in women which may in part explain the gender differences in sleep apnea associated symptoms.

Adult↗
PubMedDate not supplied

["Tailored" polysomnography: an alternative method in the assessment of obstructive sleep apnea syndrome].

The conventional study of obstructive sleep apnea syndrome (OSAS) requires two polysomnographic recordings on two different nights, one for diagnosis and the other for determining an effective level of continuous positive airway pressure (CPAP). In this study we examined an alternative method requiring a single night of polysomnographic recording encompassing both diagnostic and treatment functions. In order to obtain recordings of all phases of sleep, as well as recordings taken in supine decubitus position, the duration of polysomnographic readings was individualized ("made to order" polysomnograms). A single-night session was sufficient for diagnosis and for adjusting treatment in most cases. In some cases the night was extended well into the morning hours in an effort to obtain all the necessary data. "Made-to-order" polysomnograms were compared to traditional ones by contrasting breathing parameters (the U of Mann Whitney) and sleep architecture findings for two groups of men diagnosed consecutively of OSAS. Thirty-four patients were studied over two nights (mean age: 50 years; BMI 37 Kg/m2). Forty-six patients (mean age: 49 years; BMI: 38 Kg/m2) were studied in single-night sessions. The differences between the two groups were not significant. For most patients studied in "made to order" sessions, all sleep stages were recorded and readings were taken in supine position. REM sleep was not recorded, however, for 26% of the patients in this group. No significant differences between the double- and single-session groups were found for apnea (51 versus 62), maximum oxygen desaturation (72% versus 75%) and effective CPAP level (9 versus 10 cm H2O). These data suggest that both study methods are equally useful for evaluating OSAS severity and for prescribing effective CPAP treatment. We discuss, however, the need to arrange for two-night studies in the minority of patients for whom no REM sleep recordings become available during a single session.

Humans↗
PubMed1991

"Near miss" death in obstructive sleep apnea: a critical care syndrome.

OBJECTIVE: The objective of this study was to alert critical care physicians to the syndrome of obstructive sleep apnea with respiratory failure ("near miss" death) and to elucidate characteristics that might allow earlier recognition and treatment of such patients. DESIGN: We examined clinical and laboratory characteristics of eight patients with obstructive sleep apnea presenting to the ICU with respiratory failure. These characteristics were compared with those of eight stable apnea patients of similar severity but without a history of presentation with respiratory failure. SETTING: Medical ICU and pulmonary outpatient clinic at the Houston Veterans Administration Medical Center, a teaching hospital affiliated with Baylor College of Medicine. PATIENTS: Eight patients with obstructive sleep apnea who presented in, or developed, acute respiratory failure requiring tracheal intubation and mechanical ventilation were matched to eight stable obstructive sleep apnea outpatients from the chest clinic. MEASUREMENTS AND MAIN RESULTS: The records of these 16 patients were reviewed and multiple characteristics that might predict these obstructive sleep apnea patients prone to respiratory failure and death (called the "near miss" death group; n = 8) were examined. The mean age of the near miss group was 57 yrs. All eight patients presented with respiratory acidosis (mean pH 7.22), hypercarbia (mean PaCO2 82 torr [10.9 kPa]), and hypoxemia (mean PaO2 45 torr [6.0 kPa]). Six of the eight patients had concomitant chronic obstructive pulmonary disease as determined by clinical characteristics and spirometry. Predisposing factors included facial trauma, lower respiratory tract infections or bronchospasm, and use of pain medication. All but one of the near miss subjects had awake hypercarbia (mean PaCO2 49 torr [6.5 kPa]) and hypoxemia (mean PaO2 58 torr [7.7 kPa]) during periods of clinical stability while only two controls had concomitant chronic obstructive pulmonary disease and none had hypercarbia. The prevalence of a history of wheezing and prior hospitalization for "respiratory problems" were greater in the near miss group. Once cured of apnea, no patient presented with recurrence of respiratory failure in follow-up ranging from 6 to 80 months, and cor pulmonale recurred in only one patient during subsequent onset of central apneas. CONCLUSION: Patients with obstructive sleep apnea who have concomitant chronic obstructive pulmonary disease or hypercarbia and hypoxemia are more prone to develop severe respiratory failure and probable death than those patients with apnea alone. The current study shows that recurrent respiratory failure and presumably mortality from this acute complication can be reversed with effective treatment of the obstructive apnea.

Acute Disease↗
PubMed1986

Reversible obstructive sleep apnea caused by occupational exposure to guar gum dust.

This report describes a case of reversible obstructive sleep apnea caused by occupational exposure to an inhaled allergen, guar gum powder. The patient, a pet food plant employee, also experienced severe cough, rhinitis, and conjunctivitis. Skin tests confirmed the specific guar allergy. Pharyngeal cross-sectional area was smaller than normal. Pulmonary function studies, histamine challenge tests, nasal air-flow resistance measurements, and nocturnal polysomnography were performed on 3 separate occasions: while the patient was working at his usual occupation, at the end of a 3-wk holiday, and after a guar dust challenge in an inhalation chamber. Pulmonary function and histamine challenge tests were consistently normal. At the time of the initial tests, nasal resistance was elevated, and nocturnal polysomnography revealed obstructive sleep apnea. After absence from work, obstructive sleep apnea resolved, and the nasal resistance returned to normal. After challenge with guar gum dust, the patient developed increased resistance to nasal air flow, and obstructive sleep apnea reappeared. This case demonstrates that allergy can cause reversible obstructive sleep apnea and that occupational exposure should be considered in the assessment of patients with this disease.

Adult↗
PubMed1999

Effects of obstructive sleep apnea on endothelin-1 and blood pressure.

OBJECTIVE: To evaluate blood pressure and humoral vasoconstrictor responses to recurrent episodes of obstructive sleep apnea and the effects of therapy by means of continuous positive airway pressure. PATIENTS AND METHODS: We prospectively evaluated overnight changes in hemodynamics, oxygen saturation, the apnea-hypopnea index, circulating endothelin-1, norepinephrine and plasma renin activity in 22 patients with severe obstructive sleep apnea before and after successful therapy using continuous positive airway pressure therapy (three measurements). Measurements of endothelin-1 and blood pressure were also obtained on three occasions, at similar times, in 12 healthy control subjects without sleep disturbances. RESULTS: Mean arterial pressure and endothelin-1 concentrations increased significantly after 4 h of untreated obstructive sleep apnea, and decreased after 5 h of continuous positive airway pressure. Changes in endothelin-1 levels were correlated with changes in mean arterial pressure (r = 0.44, P < 0.02) and with changes in oxygen saturation (r = 0.37, P < 0.05). Norepinephrine levels and plasma renin activity did not change significantly in patients with obstructive sleep apnea, and were not correlated with changes in blood pressure or oxygen saturation. In controls, blood pressure measurements at similar times during the night showed changes directionally opposite to that seen in obstructive sleep apnea, while endothelin-1 levels remained unchanged. CONCLUSIONS: Sleep apnea elicits increases in blood pressure and endothelin-1, with reductions in both after treatment. Vasoconstrictor and mitogenic effects of endothelin-1 may be implicated in increased cardiovascular risk in patients with obstructive sleep apnea.

Angiotensin I↗
PubMed1986

[Therapy of obstructive sleep apnea syndrome].

Symptomatology and sequelae, as well as diagnosis and therapy of the obstructive sleep apnea syndrome are discussed. The Esmarch prosthesis, which we developed for the prosthetic treatment of obstructive sleep apnea syndrome, was tested in 7 patients. Patients were polysomnographically recorded during two sequential nights with and without Esmarch prosthesis. All apnea parameters improved significantly (apnea time by 78%, apnea index by 67% of baseline values). The mean duration of the remaining apnea phases diminished by 31%. Improvement of O2 saturation of haemoglobin and O2 partial pressure in the tissue paralleled that of the apnea parameters. The severely disturbed sleep profile of the patients showed a clear tendency towards normalization. The Esmarch prosthesis is an efficient method for the treatment of the obstructive sleep apnea syndrome.

Adult↗