Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There have been very few studies assessing the long-term physiological effects of nasal continuous positive airway pressure (CPAP) for the obstructive sleep apnoea syndrome. We therefore investigated prospectively the evolution of lung function, arterial blood gases and pulmonary haemodynamics in patients with this syndrome treated with CPAP. Sixty five patients were included. The mean duration of home treatment with nasal CPAP was 64+/-6 months. Most of the patients (77%) were smokers at the baseline assessment. We observed a small, but significant, decrease in forced expiratory volume in one second (FEV1) from 80+/-21% at baseline (t0) to 76+/-21% of the predicted value at the follow-up evaluation (t5) (p<0.01). Arterial oxygen tension (P[a,O2]) for the group as a whole remained stable (9.4+/-1.5 kPa (71+/-11 mmHg) versus 9.4+/-1.2 kPa (71+/-9 mmHg)). However, P(a,O2) increased in the subgroup of patients with hypoxaemia at t0 (n=23), from 7.8+/-0.7 kPa (59+/-5 mmHg) to 8.9+/-1.2 kPa (67+/-9 mmHg). Arterial carbon dioxide tension (P[a,CO2]) for the group as a whole increased slightly, but significantly, from 5.2+/-0.7 kPa (39+/-5 mmHg) to 5.4+/-0.5 kPa (41+/-4 mmHg) (p<0.05). Mean pulmonary artery pressure (Ppa) at rest did not change (16+/-5 mmHg versus 17+/-5 mmHg; NS) nor did exercising Ppa. In the 11 patients with pulmonary hypertension at t0, Ppa was 24+/-5 mmHg at t0 versus 20+/-7 mmHg at t5 (NS). We conclude that the significant decrease of forced expiratory volume in one second after 5 yr follow-up was related to a high percentage of smokers and exsmokers in the study population. Daytime arterial oxygen tension and pulmonary artery pressure remained stable in an unselected series of 65 obstructive sleep apnoea syndrome patients treated for 5 yrs with nasal continuous positive airway pressure, unlike arterial carbon dioxide tension, which increased by a small, but significant, amount.
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PMID:Five-year effects of nasal continuous positive airway pressure in obstructive sleep apnoea syndrome. 942 98

Sleep apnea is associated with episodic increases in systemic blood pressure. We investigated whether transient increases in arterial pressure altered upper airway resistance and/or breathing pattern in nine sleeping humans (snorers and nonsnorers). A pressure-tipped catheter was placed below the base of the tongue, and flow was measured from a nose or face mask. During non-rapid-eye-movement sleep, we injected 40- to 200-microgram i.v. boluses of phenylephrine. Parasympathetic blockade was used if bradycardia was excessive. Mean arterial pressure (MAP) rose by 20 +/- 5 (mean +/- SD) mmHg (range 12-37 mmHg) within 12 s and remained elevated for 105 s. There were no significant changes in inspiratory or expiratory pharyngeal resistance (measured at peak flow, peak pressure, 0.2 l/s or by evaluating the dynamic pressure-flow relationship). At peak MAP, end-tidal CO2 pressure fell by 1.5 Torr and remained low for 20-25 s. At 26 s after peak MAP, tidal volume fell by 19%, consistent with hypocapnic ventilatory inhibition. We conclude that transient increases in MAP of a magnitude commonly observed during non-rapid-eye-movement sleep-disordered breathing do not increase upper airway resistance and, therefore, will not perpetuate subsequent obstructive events.
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PMID:An induced blood pressure rise does not alter upper airway resistance in sleeping humans. 945 46

We postulated that three extremely obese Yucatan miniature pigs would have more sleep apnea than three nonobese Yucatan miniature pigs. Pigs were studied with the use of electroencephalograms, inductance plethysmography, oximetry, expired nasal CO2, or thermistors. All of the obese pigs, but none of the nonobese pigs, had both sleep apnea (8.5, 10.3, and 97.0 in obese pigs vs. O apnea + hypopnea/h in all nonobese pigs; P < 0.05) and oxyhemoglobin desaturation episodes during sleep [9.4 +/- 3.0 vs. 0 + 0.53 (SD) mean desaturation episodes/h in obese pigs vs. nonobese pigs, respectively; P < 0.05]. Two of the extremely obese pigs had obstructive sleep apnea, whereas the third obese pig had central sleep apnea. We conclude that sleep apnea occurs in extremely obese Yucatan minipigs and suggest that this animal can be used as a model for sleep apnea in obesity.
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PMID:Sleep apnea in obese miniature pigs. 947 62

Noninvasive positive pressure ventilation (NPPV) can improve ventilation in obese subjects during the postoperative period after abdominal surgery. Compared to nasal continuous positive airway pressure (nCPAP), NPPV was superior in correcting blood gas abnormalities both during the night-time and during the daytime in a subgroup of patients with the obesity hypoventilation syndrome (OHS). However, as it is unknown, if and to what extent NPPV can unload the respiratory muscles in the face of the increased impedance of the respiratory system in obesity, this is what was investigated. Eighteen obese subjects with a body mass index > or = 40 kg x m(-2) were investigated during the daytime, which included five healthy controls (simple obesity (SO)), seven patients with obstructive sleep apnoea (OSA) and six patients with the obesity hypoventilation syndrome (OHS). Assisted PPV was performed with bi-level positive airway pressure (BiPAP), applied via a face mask. Inspiratory positive airway pressure (IPAP) was set to 1.2 or 1.6 kPa and expiratory positive airway pressure (EPAP) was set to 0.5 kPa. Inspiratory muscle activity was measured as diaphragmatic pressure time product (PTPdi). Comparison of spontaneous breathing with BiPAP ventilation showed no significant difference in breathing pattern, although there was a tendency towards an increase in tidal volume (VT) in all three groups and a decrease in respiratory frequency (fR) in patients with OSA and OHS. End-tidal carbon dioxide (PET,CO2) with BiPAP was unchanged in SO and OSA, but was decreased in OHS. In contrast, inspiratory muscle activity was reduced by at least 40% in each group. This was indicated by a decrease in PTPdi with BiPAP 1.2/0.5 kPa from mean+/-SD 39+/-5 to 20+/-9 kPa x s (p<0.05) in SO, from 42+/-7 to 21+/-8 kPa x s (p<0.05) in OSA, and from 64+/-20 to 38+/-17 kPa x s (p<0.05) in OHS. With BiPAP 1.6/0.5 kPa, PTPdi was further reduced to 17+/-6 kPa x s in SO, and to 17+/-6 kPa x s in OSA, but not in OHS (40+/-22 kPa x s). We conclude that noninvasive assisted ventilation unloads the inspiratory muscles in patients with gross obesity.
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PMID:Influence of noninvasive positive pressure ventilation on inspiratory muscle activity in obese subjects. 949 72

Sleep apnoea is common in patients with heart failure. While most patients have central sleep apnoea (CSA), a minority have obstructive sleep apnoea (OSA). The pathophysiology of CSA is not well understood. We hypothesized that central chemosensitivity would be an important pathophysiological factor in patients with CSA, and not in OSA. The aim of this study was to compare ventilatory responses between patients with CSA and those with OSA. Acute ventilatory responses to eucapnic hypoxia and hyperoxic hypercapnia were measured during wakefulness in 34 patients (33 males and one female, aged 59+/-8 yrs (mean+/-SD)), with stable medically-treated left ventricular dysfunction (LVD) and sleep apnoea (18 OSA and 16 CSA). Patients with CSA had a decreased awake end-tidal carbon dioxide tension (4.1+/-0.5 kPa), increased ventilatory response to carbon dioxide (0.65+/-0.43 L.min.(-1).kPa PCO2(-1)), and eucapnic hypoxic responses in the normal range (0.6+/-0.4 L.min(-1)/% fall in arterial oxygen saturation (Sa,O2)). In contrast, patients with OSA had normal end-tidal carbon dioxide tension (4.9+/-0.5 kPa), and normal ventilatory responses to hypercapnia (0.29+/-0.16 L.min(-1).kPa PCO2(-1)) and hypoxia (0.5+/-0.5 L-min(-1)/% fall in Sa,O2). These findings suggest that augmented chemosensitivity to hypercapnia may be an important factor in the pathophysiology of central sleep apnoea in patients with heart failure.
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PMID:Ventilatory control in patients with sleep apnoea and left ventricular dysfunction: comparison of obstructive and central sleep apnoea. 954 61

We evaluated the effect of non-invasive nocturnal ventilation with the bi-level positive airway pressure (BiPAP) ventilator in 12 overweight patients with verified obstructive sleep apnoea syndrome (OSAS) and nocturnal hypercapnia. All patients exhibited subsequently less overnight CO2 accumulation (p < 0.0001), the desaturation event frequency was reduced (p < 0.002), daytime O2 tension rose (p < 0.001), daytime CO2 tension was reduced (p < 0.01), and apnoeas were eliminated. All symptoms characterising the syndrome, when present at the beginning of the therapy, were eliminated during the treatment. Patient compliance was high. This study showed that OSAS patients with hypercapnia can be effectively treated by BiPAP ventilation during sleep.
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PMID:Bi-level positive airway pressure treatment of obstructive sleep apnoea syndrome. 958 Sep 22

Obstructive sleep apnoea syndrome (OSAS) is associated with systemic arterial hypertension and cardiac arrhythmias and may lead to cardiovascular complications. Dysfunction of the autonomic nervous system (ANS) may play a role in the development of cardiovascular complications. The aim of this work was to study the ANS by spectral analysis of the heart rate variability (HRV) at rest and after stress (head-up tilt test) in a group of normotensive awake OSAS subjects. We studied 22 males with OSAS, aged 47.6 +/- 13.1 yrs, with a body mass index (BMI) 35.6 +/- 7.7 kg.m-2 and blood systolic and diastolic pressure (BSP and BDP, respectively) of 128 +/- 16 and 80 +/- 9 mmHg. Nineteen healthy males were studied as controls. Autonomic investigations were performed using the computerized power spectral analysis of HRV with autoregressive modelling which identifies low frequency (LF), as a marker of sympathetic activity and high frequency (HF), as a marker of vagal activity. OSAS patients showed greater sympathetic activity (LF) at rest than normal subjects, and an abnormal response to the head-up tilt test compared to control subjects. Five OSAS patients behaved like control subjects. Comparison of the functional parameters between these five OSAS patients and the other 17 OSAS patients showed a statistically significant difference for only basal arterial carbon dioxide tension (Pa,CO2) and minimal nocturnal oxyhaemoglobin (HbO2) saturation (NADIR). Our study shows autonomic nervous system dysfunction in patients with obstructive sleep apnoea syndrome, which may have facilitated a pathophysiological link with the cardiovascular complications observed in these patients.
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PMID:Autonomic dysfunction in normotensive awake subjects with obstructive sleep apnoea syndrome. 963 3

One month administration of acetazolamide (ACET) (at sea level) improves periodic breathing and decreases the number of central apneas (CA) (De Backer et al., 1995 Am. J. Respir. Crit. Care Med. 151, 87-91) in nonhypercapnic central apnea syndrome. It remains unclear whether cessation of therapy would provoke recurrence of symptoms. In the present study we evaluated the number of CA after 1 and 6 months interruption of ACET therapy. Eight patients with central sleep apnea were included [central apnea index (CAI) > 5 or apnea and hypopnea index (AHI) > 10 and obstructive apnea index (OAI) < 5]. Polysomnography was repeated once after 1 month treatment (N2), after 1 month off treatment (N3) and after 6 months off treatment. CAI (25 +/- 10 at N1) decreased during N2 (4 +/- 2) and N3 (5 +/- 3) and remained low after N4 (3 +/- 1). However an increase in the number of obstructive apneas and central hypopneas could be observed together with a shift from central apnea to hypopnea after N4. Maybe ACET induces a long lasting resetting of the CO2 threshold which is still present after interruption of the therapy.
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PMID:Central sleep apnea after interrupting longterm acetazolamide therapy. 969 83

The operation of Laser Assisted Uvulopalatoplasty (LAUP) as described by Kamami is now becoming more commonly used in the treatment of snoring and obstructive sleep apnoea. The authors have treated 95 snoring patients, varying the lengths of the soft palate incisions and percentage of uvula excised. All operations were carried out under general anaesthesia using a CO2 laser. Pilot studies showed incisions that are 25% of the distance between the free edge of the soft palate to the hard palate junction and excision of 50% of the uvula give good results with minimal complications. A further study using these parameters was conducted and postoperative evaluation including polysomnography confirmed this procedure to be effective in reducing snoring levels both subjectively and objectively.
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PMID:Laser Assisted Uvulopalatoplasty: an objective evaluation of the technique and results. 976

The paper concerns surgical treatment of rhonchus. 41 patients with rhonchus and sleep apnea were examined and treated. The patients were characterized by obesity, short fat neck, diseases of the upper respiratory tracts (chronic tonsillitis, adenoids, distortion of the nasal septum, deformity of the external nose, weakness of the palatine curtain). After cleansing of the upper respiratory tracts and recovery of nasal breathing all the patients underwent CO2 laser surgery on the soft palate with good effect.
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PMID:[On aspects of surgical treatment of pathological snoring]. 979 29


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