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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CO2 laser pharyngotomy is a newly described technique used in treatment bronchopathy without sleep apnea syndrome. Retrospective results of 70 CO2 laser pharyngotomies and 63 surgical pharyngoplasties are studied and compared. All patients were SAS free snoring patients. The results were rated satisfactory by 54% of the CO2 Laser treated patients against 78% for classical surgery. CO2 laser pharyngotomy is an easy procedure done in the office. The complication rate is very low. The predictive criteria upon which one can select the best procedure for each particular patient remain largely unknown.
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PMID:[Treatment of simple snoring. Surgical pharyngoplasty vs. laser CO2 pharyngotomy]. 129 80

Intracranial pressure changes and poor cerebral perfusion have been reported in sleep apnea syndrome (SAS), but such studies have been limited due to lack of a reliable noninvasive study method. We determined the systolic (VS), diastolic (VD), and mean (VM) cerebral blood flow velocities of the middle cerebral artery in 23 individuals (12 severe SAS patients and 11 control subjects) using transcranial Doppler sonography before sleep, during sleep (NREM and REM) and upon awakening. All three velocities (VS = 87.4 cm/s compared to 104.7 cm/s, VD = 41.6 cm/s compared to 47.7 cm/s, and VM = 57.0 cm/s compared to 67.0 cm/s) were decreased in patients with SAS and VS and VM were significantly lower than in control subjects (p = 0.005 and p = 0.033, respectively). The end-tidal CO2 (PETCO2) in the SAS patients (47.3 mm Hg) compared to the control subjects (41.8 mm Hg) was significantly higher (p = 0.003). When the VM was adjusted to normalized CO2 using the Markwalder's equation, the reduction in velocity in patients with SAS (47.5 cm/s) compared to control subjects (63.0 cm/s) became more significant (p = 0.005). This study shows that cerebral blood flow velocities are lower in patients with SAS compared to control subjects and that transcranial Doppler sonography may be useful in such evaluations.
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PMID:Intracranial hemodynamics in sleep apnea. 142 59

In 32 patients with sleep apnea syndrome (SAS), pulmonary function, blood gases and the ventilatory response to CO2 (CO2 VR) were studied before and 6 months after uvulopalatopharyngoplasty. Nine of the SAS patients had airway obstruction (AO-SAS), defined as FEV1.0 < or = 72% of the predicted value. They had a significantly higher PaCO2, lower PaO2 and a lower CO2 VR than the remaining SAS patients. Preoperatively 4 SAS patients were hypercapnic (PaCO2 > 5.8 kPa) and compared with the normocapnic ones they were more obese; in 3 of them FEV1.0 was < or = 72%. The hypercapnic SAS patients had a significantly lower CO2 VR. The CO2 VR was significantly correlated to AO and the degree of oxygen desaturation during sleep, but not to the number of episodes of apnea and hypopnea nor their length. The VR to CO2 did not predict the postoperative outcome. Postoperatively 2 hypercapnic obese AO-SAS patients showed a large decrease in episodes of apnea and hypopnea and an increase in CO2 VR, and became normocapnic. Other patients showed no consistent changes in CO2 VR postoperatively.
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PMID:Airway obstruction, obesity and CO2 ventilatory responsiveness in the sleep apnea syndrome. 147 13

Infants experiencing apparent life-threatening events (ALTE) have been reported to have elevated frequencies of periodic breathing and obstructive apnea when compared to presumably normal control groups. Whether these characteristics extend to the siblings of ALTE infants remains unknown. This study compared, retrospectively, the apnea indices of 13 first-born infants experiencing an ALTE with their subsequent asymptomatic siblings who had undergone polygraphic sleep apnea evaluations (including electrocardiogram, chest wall movements, expired CO2, and transcutaneous pulse oximetry). Gestation, birthweight, age at study, apnea and periodic breathing indices, and oxygen desaturations were compared. Regression analyses revealed that adjustments for gestational and postnatal age eliminated differences in apnea indices. ALTE infants and their subsequent siblings experienced similar rates of apnea. Neither group had elevated rates of prolonged central apneas (greater than 10 seconds duration) or periodic breathing (greater than 5% sleep time). Neither group had subsequent severe apneas. The use of polygraphic study and cardiac/apnea monitors in subsequent siblings of ALTE are unnecessary and should be considered only when there is parental disagreement.
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PMID:Apnea in subsequent asymptomatic siblings of infants who had an apparent life-threatening event. 152 29

Periodic increases in blood pressure (BP) can occur in the sleep apnea syndrome (SAS) during recurrent apneas. To investigate the mechanisms causing this periodic hypertension, we simulated SAS by imposing a matching breathing pattern on seven healthy awake male volunteers. Continuous finger arterial BP, electrocardiogram, arterial O2 saturation (SaO2), end-tidal CO2, and tidal volume were measured. The role of hypoxia was studied by comparing apneas during depletion of O2 in the spirometer with those during 100% O2 breathing. In all subjects, BP periodically reached values greater than 150/95 mmHg in the hypoxic series. During the hyperoxic apnea series, however, BP remained stable. End-apneic mean BP was shown to be inversely correlated to SaO2 in six subjects in the SaO2 range from 60 to 100%. Although the hypoxic BP pattern closely mimicked that in SAS, the heart rate pattern in four of our subjects remained distinct from that in patients. Atropine could not prevent large BP swings in the hypoxic series. We conclude that SaO2 is a major determinant of periodic hypertension in recurrent apneas. Its effect probably results from chemoreflex modulation of peripheral resistance.
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PMID:Repetitive apneas induce periodic hypertension in normal subjects through hypoxia. 156 78

Sleep disorders, including a high incidence of sleep apnea, have been recognized as a significant problem in chronic renal failure (CRF) patients. In a preliminary study, we examined CRF patients on maintenance hemodialysis for three nights; one control night, and thereafter randomized to infusion of saline (placebo) for one night and 4% branch-chain amino acid (BCAA) solution for one night. Polysomnographic and respiratory data [respiratory rate, oxygen saturation and end-tidal CO2 (ETCO2)] was recorded continuously throughout the nights and data from each hour compared with baseline (awake) values. The patients studied were characterized by reduced sleep quality and decreased amount of rapid eye movement (REM) sleep. The BCAA infusion was associated with a return of REM sleep to normal and a significant decrease in ETCO2 during both REM and non-REM sleep (P less than 0.05). Our findings demonstrate respiratory stimulation during sleep with infusion of BCAA; this stimulatory effect on respiration (in contrast to many respiratory stimulants) is associated with an increased amount of REM sleep.
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PMID:Branched-chain amino acid in chronic renal failure patients: respiratory and sleep effects. 178 51

The enlarged adenoid is a common disorder in children resulting in nasopharyngeal obstruction. Many authors suggest that increased nasal resistance to respiration may cause disturbances in the pulmonary ventilation and carry the risk of obstructive sleep apnoea and/or cardiopulmonary syndrome. This study comprised 30 children complaining of long-standing nasal obstruction due to enlarged adenoids. Adenoidectomy was performed and the arterial blood gases were measured before and one month after surgery. Twelve normal children were also included as controls. Statistical evaluation of the results showed that O2 saturation and arterial O2 tension (PaO2) were significantly low before the operation, and increased significantly after surgery. Arterial CO2 tension (PaCO2) was insignificantly low before operation, but decreased significantly after adenoidectomy. It was concluded that enlarged adenoid may be associated with ventilatory impairment which is reversible after adenoidectomy.
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PMID:Effect of enlarged adenoids on arterial blood gases in children. 190 19

A theoretical analysis of the CO2 control of the respiratory system is presented using both analytic and simulation techniques. A stability index (SI) is obtained by linearizing a dynamic first-order model with a time delay. Analytically, SI values greater than unity predict an unstable response to a disturbance. Because the first-order model is reduced from a higher-order physiological model, SI can be algebraically related to physiological parameters. This relationship shows that SI increases with a decrease in system tissue volume, metabolic rate, or inspired CO2 partial pressure; SI decreases with a decrease in time delay, cardiac output, controller gain, or controller intercept. Analytically, SI distinguishes stable from unstable domains. By simulations of the nonlinear first-order model, three domains are obtained: an unstable domain (sustained oscillations, SI greater than 1.1), an underdamped stable domain (transient oscillations, 0.3 less than SI less than 1.1), and an overdamped stable domain (no oscillations, 0 less than SI less than 0.3). With this classification, disturbances such as change of state (e.g., from awake to asleep) or sigh may produce transient oscillations if the system becomes underdamped even though stable. Potential applications of this work include quantitative distinction of the physiological factors in control disorders associated with short-term periodicities (e.g., Cheyne-Stokes breathing, sleep apnea, breathing at altitude).
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PMID:Stability analysis of CO2 control of ventilation. 212 1

The distribution of symptoms, physiologic responses, and upper airway structure in members of one family with three generations of subjects with sleep apnea (SA) is reported. Questionnaire data were obtained from ten family members (ages 7 to 66 years), overnight sleep studies were performed in nine subjects, and ventilatory responses to hyperoxic hypercapnia and to eucapnic hypoxia and cephalometry were obtained in five subjects. All ten family members reported habitual snoring or nighttime snorting/gasping; five of ten family members also reported excessive daytime sleepiness. All studied subjects except for a pregnant woman had greater than ten apneas/hypopneas per hour. Ventilatory responses to hypoxia were markedly reduced in all five subjects studied (less than or equal to 0.51 L/min/SaO2); hypercapnic responses were reduced in three of five subjects (less than or equal to 0.61 L/min/mm Hg CO2). No subject was morbidly obese (body mass index less than 29 kg/m2) or demonstrated retrognathia. The posterior airway space was reduced in three subjects, and the mandibular to hyoid distance was increased in four subjects. The two subjects with the longest soft palates and the most inferiorly displaced hyoids had the most severe sleep disorder. Sleep apnea was present, albeit less profound, in the one subject with normal anatomy who had an abnormal hypoxic ventilatory response. The distribution of these physiologic and anatomic measurements in this family provides further support for a genetic basis for SA, and suggests that the disorder may occur as a result of interactions between ventilatory control abnormalities and anatomic risk factors.
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PMID:A family study of sleep apnea. Anatomic and physiologic interactions. 239 35

We investigated the mechanisms of the beneficial effect derived from progesterone therapy for sleep apnea syndrome (SAS). Nine patients with SAS were treated for 7 days with chlormadinone acetate (CMA), a respiratory stimulant known to increase not only CO2 and hypoxic chemosensitivity but also respiratory drive response for ventilatory loading. They were examined as to sleep events and ventilatory control during wakefulness before and during CMA treatment. Apnea-hypopnea index was significantly reduced from 51.1 +/- 5.7 to 43.6 +/- 8.1 episodes/h (p less than 0.05). The ratio of desaturation time with more than 4% SaO2 fall to total sleep time was diminished in seven of nine patients, and its mean value decreased from 44.9 +/- 8.6 to 28.7 +/- 8.1% (p less than 0.05). Both hypercapnic ventilatory response (HCVR) and load response during wakefulness were significantly increased, although isocapnic hypoxic ventilatory response (HVR) was not significantly enhanced by CMA. The degree of augmentation in awake load response as well as in HCVR was positively correlated with that of improvement in sleep-disordered breathing. Moreover, patients who did not show amelioration in oxygen desaturation were found to be incapable of increasing load response despite increased HCVR. We conclude that CMA therapy for sleep apnea syndrome is effective in the patients whose load response as well as respiratory control activity are augmented during wakefulness.
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PMID:Progesterone therapy for sleep apnea syndrome evaluated by occlusion pressure responses to exogenous loading. 246 68


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