Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The obesity-hypoventilation syndrome (or alveolar hypoventilation in the obese) is a new name for an old syndrome, Pickwickian syndrome. It is defined as chronic alveolar hypoventilation (PaO(2)<70 mmHg, PaCO(2) > 45 mmHg) in obese patient with a body mass index > 30 kg/m(2) who have no other respiratory disease explaining the gas anomalies. The large majority of obese subjects are not hypercapnic, even in case of severe obesity. There are three principal causes explaining alveolar hypoventilation in obese subjects: high cost of the work of respiration, dysfunction of the respiratory centers, repeated episodes of nocturnal obstructive apnea. The obesity-hypoventilation syndrome is generally found in males aged over 50 years. Exercise-induced breathlessness is a constant finding. Diagnosis is often made after an episode of severe respiratory failure. Associated diseases favored by obesity are frequent: diabetes, high blood pressure, heart disease. By definition, there is a hypoxemia-hypercapnia syndrome persisting after an acute episode. Spirography usually demonstrates moderate volume restriction. Pulmonary hypertension is frequent but not constant. Obesity-hypoventilation syndrome must be distinguished from obstructive sleep apnea, although the two conditions are often associated. Obstructive sleep apnea may be absent in certain patients with obesity-hypoventilation syndrome (we have had several cases) and inversely, obesity is not observed in certain patients with obstructive apnea. It should be recalled that the term Pickwickian syndrome designates obesity-hypoventilation syndrome (with or without obstructive apnea) and not obstructive sleep apnea syndrome.
 ...
PMID:[Alveolar hypoventilation in the obese: the obesity-hypoventilation syndrome]. 1208 46

The effects of hypoxia and hypercapnia on contractile and histological properties of the diaphragm and skeletal muscles of the hind limb were examined. Eight-week-old male Sprague-Dawley rats ( [Formula: see text] ) were kept in hypobaric hypoxic ( [Formula: see text] ) or hypercapnic ( [Formula: see text] ) chambers for 6 weeks, and compared with the control rats (room air, [Formula: see text] ). Contractile properties were evaluated with twitch kinetics, force-frequency curve and fatigue tolerance. After the experiments on contractile activities, muscles were fixed for histological examination with ATPase staining. It was demonstrated that peak twitch tension of diaphragm decreased with no significant histological changes under hypoxic conditions while significant contractile and histological changes were observed under hypercapnic conditions. Skeletal muscles of the hind limbs were affected also under hypoxic and hypercapnic conditions but the profiles of the changes in contraction and histology were different from those of the diaphragm. These results suggest that hypoxia and hypercapnia affect differently on contractile and histological properties of respiratory and hind limb muscles. Furthermore, when we consider the conditions involved in chronic obstructive respiratory disease (COPD; both hypoxia and hypercapnia are deeply involved), our results indicate that COPD should be regarded as a systemic disorder rather than a respiratory disease.
 ...
PMID:Hypoxia and hypercapnia affect contractile and histological properties of rat diaphragm and hind limb muscles. 1517 12

Permanent tracheotomy was the first surgical procedure proposed for the treatment of severe obstructive sleep apnoea syndrome and is still the only surgical option that ensures, even in very severe cases, complete elimination of apnoea and, in turn, clinical remission. Improved knowledge of the causes of obstructive sleep apnoea syndromes and the increasing therapeutic options (instrumental, medical and surgical) have resulted in cases requiring tracheotomy as the only indispensable therapeutic option becoming more rare. At present, the only indications are in very occasional conditions of life-threatening obstructive sleep apnoea syndromes and in patients on whom continuous positive airway pressure is not tolerated or is not effective (severe deoxygenation or hypercapnia, severe respiratory disorder index, severe obstructive sleep apnoea syndrome-related arrhythmias, severe excessive daytime sleepiness, heart diseases or ischaemic encephalopathy exacerbated by obstructive sleep apnoea syndromes, obstructive pneumopathy exacerbated by obstructive sleep apnoea syndromes, severe obstructive sleep apnoea syndromes with few chances of resolution with other surgical procedures or failure of the latter). Moreover, it is the only therapeutic solution in rare nocturnal laryngeal stridor due to multisystemic atrophy (in which obstructive sleep apnoea syndrome is due to nocturnal laryngospasm of neurologic origin). Therapeutic tracheotomy must be permanent (tracheostomy) and, therefore, preferably carried out with a specific technique (skin-lined tracheotomy), able to guarantee greater stability, less risk of granulation tissue, wider opening of the tracheostomy, sufficient reversibility. In our experience, very few patients (10 cases) withsleep disorder breathing have been submitted to skin-lined tracheotomy. Of these, the majority were submitted to surgery for severe apnoea due to nocturnal laryngospasm on account of multisystemic atrophy (n = 7), while only 3 cases of obstructive sleep apnoea syndromes were submitted to skin-lined tracheotomy, i.e., 0.7% of the 424 patients operated on for obstructive sleep apnoea syndrome and 1.7% of the 175 operated on for severe, or very severe, obstructive sleep apnoea syndromes (RDI > 40). Skin-lined tracheotomy was not followed by important complications and expected results were achieved with immediate disappearance of daytime symptoms and considerable improvement in nocturnal apnoea. Besides sleep-related disorders, numerous clinical situations with indications for a permanent tracheotomy may benefit from the skinlined technique, such as severe laryngeal or tracheal stenoses, laryngeal diplegias, miasthenia gravis, lateral amyotrophic sclerosis, intractable aspiration, severe emphysema.
 ...
PMID:Role of skin-lined tracheotomy in obstructive sleep apnoea syndrome: personal experience. 1546 94

Acute ventilatory failure is a challenging yet increasingly common medical emergency reflecting the growing burden of respiratory disease. It is not a diagnosis in itself but the end result of a diversity of disease processes culminating in arterial hypoxaemia and hypercapnia. This review focuses on key management issues including giving appropriate oxygen therapy, treatment of the underlying aetiology as well as any precipitant factors and provision of assisted ventilation if required. Ventilatory assistance can be provided both invasively and non-invasively and the indications for either or both forms of assisted ventilation are discussed. Further emphasis is needed regarding advanced directives of care and clinicians should be aware of ethical issues regarding assisted ventilation.
 ...
PMID:Management of acute ventilatory failure. 1682 20

In the Netherlands, a syndrome affecting several species of older Amazon parrots (Amazona sp.) has been described. This syndrome was characterized as a chronic respiratory disease resulting in exercise intolerance. Pathological examination revealed loss of functional lung tissue, pulmonary interstitial fibrosis, and right heart failure. Haematology revealed an elevated packed cell volume as a result of an increase in erythrocyte size and an increased haemoglobin mass per erythrocyte. In two patients, hypoxia and hypercapnia were demonstrated. The aetiology of this syndrome is currently not known. The microscopic lesions resemble those found in Diffuse Interstitial Fibrosis in humans.
 ...
PMID:Chronic pulmonary interstitial fibrosis in Amazon parrots. 1918 41

Obstructive sleep apnea (OSA) is associated with repetitive nocturnal arterial oxygen desaturation and hypercapnia, large intrathoracic negative pressure swings, and acute increases in pulmonary artery pressure. Rodents when exposed to brief, intermittent hypoxia for several hours per day to mimic OSA developed pulmonary vascular remodeling and sustained pulmonary hypertension and right ventricular hypertrophy within a few weeks. Until recently, however, it was unclear whether episodic nocturnal hypoxemia associated with OSA was sufficient to cause similar changes in humans. This controversy appears to have been resolved by several recent studies that have shown (a) pulmonary hypertension in 20% to 40% of patients with OSA in the absence of other known cardiopulmonary disorders and (b) reductions in pulmonary artery pressure in patients with OSA after nocturnal continuous positive airway pressure (CPAP) treatment. The pulmonary hypertension associated with OSA appears to be mild and may be due to a combination of precapillary and postcapillary factors including pulmonary arteriolar remodeling and hyperreactivity to hypoxia and left ventricular diastolic dysfunction and left atrial enlargement. Although measurable changes in the structure and function of the right ventricle have been reported in association with OSA, the clinical significance of these changes is uncertain. Right ventricular failure in OSA appears to be uncommon and is more likely if there is coexisting left-sided heart disease or chronic hypoxic respiratory disease.
 ...
PMID:Obstructive sleep apnea and pulmonary hypertension. 1924 42

In order to make an adequate assessment of and to maintain respiratory function in patients in the intensive care unit, the nursing responsibilities include: (1) Recognition of physiologic and psychologic changes related to respiratory disease. (2) Appreciation of individual reactions to respiratory stressful situations, particularly during periods of hypoxemia and hypercapnia. (3) Awareness that behavioral changes related to changes in respiratory physiology are reversible with corrective respiratory therapy. (4) Skill in implementing the prescribed medical therapy quickly and efficiently and ability to evaluate the patient's response. (5) Assessment and appropriate involvement of the family as an essential factor in the plan for care.
 ...
PMID:Assessment and maintenance of adequate respiration. 2073 71

There has been increasing recognition of pre-motor manifestations of Parkinson's disease (PD) resulting from early brainstem involvement. We sought to determine whether ventilatory control is abnormal. Patients with PD without respiratory disease were recruited. Spirometry, lung volumes, diffusing capacity and respiratory muscle strength were assessed. Occlusion pressure and ventilation were measured with increasing CO(2). Arterial blood gases were taken at rest and following 20 min exposure to 15% O(2). A linear correlation assessed associations between respiratory function and indices of PD severity. 19 subjects (17 males) with mild-moderate PD were studied (mean (SD) age 66 (8) years). Respiratory flows and volumes were normal in 16/19. Maximum inspiratory and expiratory pressures were below LLN in 13/19 and 15/19 respectively. 7/15 had a reduced ventilatory response to hypercapnia and 11/15 had an abnormal occlusion pressure. There was no correlation between impairment of ventilatory response and reduction in respiratory muscle strength. Response to mild hypoxia was normal and there were no associations between disease severity and respiratory function. Our findings suggest that patients with mild-moderate PD have abnormal ventilatory control despite normal lung volumes and flows.
 ...
PMID:Abnormal ventilatory control in Parkinson's disease--further evidence for non-motor dysfunction. 2198 17

Obstructive sleep apnoea syndrome (OSAS) is a common respiratory disorder characterized by chronic intermittent hypoxia (CIH). We have shown that CIH causes upper airway muscle dysfunction in the rat due to oxidative stress. Ageing is an independent risk factor for the development of OSAS perhaps due to respiratory muscle remodelling and increased susceptibility to hypoxia. We sought to examine the effects of CIH on breathing and pharyngeal dilator muscle structure and function in aged rats. Aged (18-20 months), male Wistar rats were exposed to alternating cycles of normoxia and hypoxia (90 s each; F(I)O(2)=5% O(2) at nadir) or sham treatment for 8h/day for 9 days. Following CIH exposure, breathing was assessed by whole-body plethysmography. In addition, sternohyoid muscle contractile and endurance properties were examined in vitro. Muscle fibre type and cross-sectional area, and the activity of key oxidative and glycolytic enzymes were determined. CIH had no effect on basal breathing or ventilatory responses to hypoxia or hypercapnia. CIH did not alter succinate dehydrogenase or glycerol phosphate dehydrogenase enzyme activities, myosin heavy chain fibre areal density or cross-sectional area. Sternohyoid muscle force and endurance were unaffected by CIH exposure. Since we have established that this CIH paradigm causes sternohyoid muscle weakness in adult male rats, we conclude that aged rats have decreased susceptibility to CIH-induced stress. We suggest that structural remodelling with improved hypoxic tolerance in upper airway muscles may partly compensate for impaired neural regulation of the upper airway and increased propensity for airway collapse in aged mammals.
 ...
PMID:Respiratory control and sternohyoid muscle structure and function in aged male rats: decreased susceptibility to chronic intermittent hypoxia. 2212 88

Understanding the effects of respiratory load on neural respiratory drive and respiratory pattern are key to understanding the regulation of load compensation in respiratory disease. The aim of the study was to examine and compare the recruitment pattern of the diaphragm and parasternal intercostal muscles when the respiratory system was loaded using two methods. Twelve subjects performed incremental inspiratory threshold loading up to 50% of their maximal inspiratory pressure, and 10 subjects underwent incremental, steady-state hypercapnia to a maximal inspired CO2 of 5%. The diaphragmatic electromyogram (EMGdi) was measured using a multipair oesophageal catheter, and the parasternal intercostal muscle EMG (sEMGpara) was recorded from bipolar surface electrodes positioned in the second intercostal space. The EMGdi and sEMGpara were analysed over the last minute of each increment of both protocols, normalized using the peak EMG recorded during maximal respiratory manoeuvres and expressed as EMG%max. The EMGdi%max and sEMGpara%max increased in parallel during the two loading methods, although EMGdi%max was consistently greater than sEMGpara%max in both conditions, inspiratory threshold loading [bias (SD) 9 (3)%, 95% limits of agreement 4-15%] and hypercapnia [bias (SD) 6 (3)%, 95% limits of agreement -0.05 to 12%]. Inspiratory threshold loading resulted in more pronounced increases in mean (SD) EMGdi%max [10 (7)-45 (28)%] and sEMGpara%max [5.3 (3.1)-40 (28)%] from baseline compared with EMGdi%max [7 (4)-21 (8)%] and sEMGpara%max [4.7 (2.3)-10 (4)%] during hypercapnia, despite comparable levels of ventilation. These data support the use of sEMGpara%max, as a non-invasive alternative to EMGdi%max recorded with an invasive oesophageal electrode catheter, for the quantification of neural respiratory drive. This technique should make evaluation of respiratory muscle function easier to undertake and therefore more readily acceptable in patients with respiratory disease, in whom transduction of neural respiratory drive to pressure generation can be compromised.
...
PMID:Neural respiratory drive measured during inspiratory threshold loading and acute hypercapnia in healthy individuals. 2350 46


<< Previous 1 2 3 4 Next >>