Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344329 (collapse)
 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the changes in the electromagnetically measured left lower lobe blood flow (QLLL) when the left lower lobe (LLL) was exposed to alveolar hypoxia selectively under two different positions (supine and right lateral position in 18 dogs. QLLL/CO, Qs/Qt and other cardiopulmonary parameters were obtained during the following experimental sequence; 1) the whole lung ventilated with 100% O2 (control), 2) LLL collapsed and the remainder ventilated with 100% O2, 3) N2 expansion of LLL (N2 CPAP) and the remainder ventilated with 100% O2, 4) O2 expansion of LLL (O2 CPAP) and the remainder ventilated with 100% O2, and 5) The whole lung ventilated with 100% O2. In the supine position group (n = 9), both selective collapse and N2 CPAP of LLL caused QLLL/CO to decrease significantly (P less than 0.02) from control values (14.9 +/- 1.7%) to 10.6 +/- 0.9% and 11.9 +/- 1.6%, respectively. But there was no difference in QLLL/CO between collapse and N2 CPAP of LLL. In the right lateral position group (n = 9), hypoxic exposure of LLL caused no decrease in QLLL/CO from control values. But QLLL/CO during N2 CPAP (8.5 +/- 1.1%) decreased significantly than that during collapse (10.8 +/- 1.5%) (P less than 0.02). Qs/Qt during N2 CPAP (15.6 +/- 1.4%) also decreased significantly (P less than 0.05) from that during collapse (18.5 +/- 2.2%). We conclude that the difference of the changes in QLLL/CO under hypoxic exposure between supine and right lateral position was caused by hydrostatic pressure which influenced more during lateral position than during supine position.
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PMID:[The influence of lung volume and body position on pulmonary blood flow under hypoxic exposure]. 161 53

Treatment of obstructive sleep apnea with nasal continuous positive airway pressure mandates simultaneous increases of both inspiratory and expiratory positive airway pressures to eliminate apneas as well as nonapneic oxyhemoglobin desaturation events. We hypothesized that the forces acting to collapse the upper airway during inspiration and expiration are of different magnitudes and that obstructive sleep-disordered breathing events (including apneas, hypopneas and nonapneic desaturation events) could be eliminated at lower levels of EPAP than IPAP. To test these hypotheses, a device was built that allows the independent adjustment of EPAP and IPAP (nasal BiPAP). Our data support the hypotheses that expiratory phase events are important in the pathogenesis of OSA and that there are differences in the magnitudes of the forces destabilizing the upper airway during inspiration and expiration. Finally, applying these concepts, we have shown that by using a device that permits independent adjustment of EPAP and IPAP, obstructive sleep-disordered breathing can be eliminated at lower levels of expiratory airway pressure compared with conventional nasal CPAP therapy. This may reduce the adverse effects associated with nasal CPAP therapy and improve long-term therapeutic compliance.
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PMID:Obstructive sleep apnea treated by independently adjusted inspiratory and expiratory positive airway pressures via nasal mask. Physiologic and clinical implications. 186 59

The OSA syndrome, described over 100 years ago, was rediscovered in 1966. It is a common disorder, especially among fat, middle-aged men. Stentorian snoring and diurnal somnolence are the cardinal manifestations and should always lead to an examination during sleep. That examination (polysomnography) can demonstrate the pathognomonic events--repetitive apneas occurring in sleep--which signal the failure of the sleeping brain to maintain the patency of the supraglottic airway. All evidence points to the problem being an abnormal pharyngeal airway, one which has a shape or size or compliance that allows inspiratory collapse as the normal loss of pharyngeal dilator muscle tone occurs with sleep. The apneas are asphyxic events terminated by arousals which fragment sleep continuity and lead to the daytime sleepiness. Because the snoring occurs during sleep, the arousals are unremembered, and the sleepiness can develop so gradually that the patient may forget what normal alertness is like. It is important to interview the patient's spouse or partner. Besides obesity and maleness, other risk factors for OSA are diseases that have an impact on the configuration or effective compliance of the pharyngeal passageway. Recent studies support the clinical intuition that sleep apnea is undesirable. Sleepiness leads to accidents. The hypoxemia occurring during apnea can lead to potentially fatal cardiac dysrhythmias. A number of reports suggest that snoring and sleep apnea are associated with an increased risk of stroke, myocardial ischemia, and infarction. Finally, there are now two papers showing a significantly decreased probability of 5-year survival in patients with symptomatic sleep apnea. The good news is that treatment with tracheostomy or NCPAP improves mortality rates to normal. Approximately 90 per cent of patients can tolerate a night's initial trial with CPAP. Long-term acceptance of CPAP has now been reviewed in a number of studies, and it appears to be about 65 to 70 per cent.
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PMID:Sleep disorders and upper airway obstruction in adults. 219 4

The action mechanism of nCPAP in the treatment of obstructive sleep apnea is not adequately known. We took video endoscopic pictures (chip video camera manufactured by Videotronik) of the pharynx in five patients with SA in the awake state, during apnea during sleep, and under nCPAP treatment during sleep. The patients were all in the supine position. Simultaneously with video-endoscopy, polysomnography was performed. Qualitatively good pictures were obtained in 3 patients. In the awake state, a relatively narrow pharynx was observed which, however, was completely patent during the entire respiratory cycle. During apnea and hypopnoea, a concentric collapse of the oropharynx was observed, with involvement of the lateral and posterior walls of the pharynx and the tongue, together with the soft palate over a length of several centimetres to above the epiglottis. During the hyperventilation phase following apnea, the occlusion opened up again, the diameter of the pharynx then being appreciably greater than that seen in the awake state. Under increasing CPAP pressure, occlusion became progressively less complete; when the effective pressure had been attained, the diameter of the pharynx was roughly comparable to that seen in the hyperventilation phase, that is, appreciably wider than in the awake state. During inspiration, however, even under effective nCPAP pressure, a discrete decrease in pharyngeal diameter occurred. On the basis of the visual impression, we believe that the effect of CPAP is based on a passive "pneumatic splinting" of the pharyngeal musculature.
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PMID:[Video-endoscopic recording of the pharynx before and following nasal continuous positive airway pressure therapy in patients with obstructive sleep apnea]. 269 21

A rare complication after delayed re-expansion of pneumothorax is reported. A polytraumatized patient with stable vital functions was admitted to our ICU immediately after surgery. Later, oxygenation worsened treated by a rise in FiO2. Concomitant tachycardia was thought to be due to increasing body temperature. On day 3 of treatment in the ICU further deterioration in gas exchange (and in hemodynamics, with complete collapse of the left lung) was diagnosed on X-ray examination. Retrospectively, the development of this condition could be traced on the X-ray films taken during the previous 3 days. Thoracic drainage and suction resulted in complete re-expansion of the lung. After re-expansion worsening of gas exchange and unilateral ARDS-like configurations were observed on chest X-ray. Reversal of the I:E ration and a rise in PEEP improved gas exchange and the X-ray appearance immediately. In the next few days the intensity of the respiratory treatment could be reduced, and after a short period of CPAP the patient was discharged from the ICU. Three mechanisms for development of this "unilateral ARDS" are discussed: loss and suppressed regeneration of surfactant in prolonged atelectic alveolar compartments; increased capillary fluid escape due to suction; and increased complement activation and reduced degradation of edematogenic bradykinin in hypoxic alveolar compartments. Possible clinical implications for the treatment of longer duration pneumothorax are: fractionated drainage and respirator settings, reopening collapsed alveoli in an inhomogeneously diseased lung such as IRV.
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PMID:[Treatment of re-expansion edema ('unilateral ARDS") after rapid pneumothorax drainage]. 342 73

Three infants presenting with respiratory distress required early ventilator support. With attempts at extubation recurrent airway obstruction occurred. The clinical course was marked by recurrent episodes of hyperinflation, atelectasis, and pneumonia. Bronchoscopy, bronchography, and chest fluoroscopy revealed extensive collapse of the trachea and main stem bronchi. Two of the infants had gastroesophageal reflux and recurrent aspiration. Treatment of tracheobronchomalacia (TBM) was carried out with a tracheostomy tube attached to a portable CPAP apparatus. Initially CPAP was maintained at 10 cm of water and subsequently weaning was achieved by gradual decreasing of both positive pressure and hours of treatment per day. Total treatment time ranged from 13 to 25 months. Feedings were carried out via gastrostomy. Two infants with severe gastroesophageal reflux underwent fundoplication. Each infant was successfully weaned from distending pressure and decanulated. The treatment of severe TBM with long-term CPAP appears to be a reasonable alternative or adjunct to surgical procedures such as tracheopexy, resection, external splinting and tracheobronchoplasty.
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PMID:Management of tracheobronchomalacia with continuous positive airway pressure. 390 98

We describe five patients with severe nocturnal cough and daytime somnolence in whom the coughing attacks are triggered by assuming the supine body position. Quantity and quality of the nocturnal cough were evaluated in the sleep laboratory with and without nasal continuous positive airway pressure (N-CPAP). Air flow characteristics were assessed using flow volume and airway resistance loops. Airway anatomy was evaluated bronchoscopically. In all five patients, the cough had a barking quality. Flow-volume loops showed an expiratory collapse phenomenon in two of the patients. Endoscopically, all five patients had signs of airway collapse. All patients had difficulty falling asleep because of coughing and were awakened by it frequently. Sleep times ranged from 2.5 to 4.5 h per night. With N-CPAP pressures ranging from 5 to 13 cm H2O, all five patients had clinically significant improvement in their symptoms. Their sleep times increased to a range of 5 to 7.5 h per night and the daytime somnolence markedly improved or resolved. All five patients requested a N-CPAP unit for home use. We conclude that a cough that is predominantly associated with or exacerbated by the supine body position may be treated effectively with N-CPAP.
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PMID:Intractable cough associated with the supine body position. Effective therapy with nasal CPAP. 763 7

All-night polysomnographic studies were performed on ten patients (all female) with rheumatoid arthritis complicated with temporomandibular joint destruction and cervical lesions. The mean age of these subjects was 67.5 yrs, ranging from 48-81 yr. They all had some morphologic abnormalities of cervical spines and/or temporomandibular joints. Sleep study revealed that all of them had sleep apnea; five of them were of obstructive type (obstructive group) while the remaining showed central type of sleep apnea (central group) predominantly. There were no statistically significant differences of the levels of apnea index, mean-nadir SO2 and the lowest SO2 between the obstructive group and the central group. No detectable differences of cephalographic measurements and MRI findings existed between the two groups either. In one patient, nasal-CPAP converted central apnea to normal breathing dramatically. Our observations indicate that the cause of central apnea in RA patients with temporomandibular lesions is collapse of upper airway, inducing inhibitory inputs from the mechanoreceptors in that region.
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PMID:[Sleep apnea syndrome in rheumatoid arthritis (RA) patients complicated with cervical and temporomandibular lesions]. 773 87

Obstructive sleep apnea results from a pharyngeal collapse. Upper airway can be investigated using either static or dynamic methods during wakefulness or when the patient is sleeping. Somnofluoroscopy is one of the dynamic methods allowing a visualization of the upper airway during sleep. A lateral projection of the pharynx is obtained during fluoroscopic examination which allows visualization of the upper airway dimensions and the bone structures (hyoid bone, cervical spine, mandible). Standard polygraphic parameters (EEG, EOG, flow rate, thoracic and abdominal movements) and fluoroscopic image are simultaneously acquired on the same videotape. Using this technique, we have described the typical pattern of events occurring during an episode of apnea: 1-beginning of airway occlusion in the oropharynx with anterior or posterior hooking of the soft palate, 2-suction on the uvula downwards and complete occlusion of the oropharynx with further extension to the hypopharynx, 3-active movements of the cervical spine and hyoid bone as if the patient is choking, 4-overcoming of the occlusion usually accompanied by opening of the jaw and occurring either as a sudden event throughout the length of the pharyngeal airway or as a progressive reopening from the hypopharynx. In a recent study, we have investigated upper airway dynamics when a continuous positive pressure with one level (CPAP) or two levels of pressure (BiPAP) was applied. When using CPAP with pressure below the optimal pressure, uvula movements were the first changes we observed, preceding the pharyngeal collapse. Lowering the expiratory pressure alone lead to a significant reduction in pharyngeal dimensions starting at expiration and extending also to inspiration when the expiratory pressure is further reduced. Using BiPAP may lead to upper airway instability. The frequency and the variability of this phenomenon need further studies to be established.
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PMID:[The dynamics of pharyngeal structures in obstructive sleep apnea (during spontaneous, continuous positive pressure and BiPAP ventilation)]. 809 Jan 56

Treatment of obstructive sleep apnea (OSA) has developed over the last 25 years from tracheostomy to a variety of options, including weight loss, nasal continuous positive airway pressure (N-CPAP), pharyngeal surgery, and medications. None of these options is definitive or curative, except possibly weight loss. The most widely prescribed treatment is N-CPAP, but recently published studies using objective measurement of patient compliance show less than ideal compliance. Attempts have been made to design pharyngeal surgery according to the site of upper airway collapse or narrowing, as identified by various techniques in wakefulness. How representative these studies are of upper airway physiology in sleep is questionable. Recent studies have shown improved surgical success in correcting OSA. However, disturbing data are available in a limited number of patients that demonstrate worsening of the OSA months after a favorable response to surgery. More studies assessing the long-term outcome of pharyngeal surgery are needed. Several pharmacologic agents have been used to treat OSA. Results with any particular agent are not better than with N-CPAP or surgery. However, studies of subgroups of patients with OSA in which a particular pharmacologic agent may be specifically indicated, such as thyroxine in hypothyroidism, have not been conducted (to our knowledge). An algorithm for the approach to treatment recommendations is presented. Basic to this algorithm is an objective presentation of therapeutic options to the patient with OSA and a respect for the patient's preferences.
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PMID:Treatment of obstructive sleep apnea. A review. 904 18


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