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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A large randomized, controlled study of NIV plus LTOT versus LTOT in patients with COPD is needed that evaluates morbidity, mortality, quality of life, and health economic impact. It is to be hoped that funding for this type of study will be forthcoming. In the meantime, it reasonably can be concluded from existing evidence that domiciliary NIV is unlikely to be effective in most patients with stable COPD, particularly if they are normocapnic. A subgroup of patients with severe hypercapnia, poor tolerance of LTOT, marked nocturnal hypoventilation, or recurrent infective exacerbations may benefit from domiciliary NIV. Systematic evaluation is required in patients with CF or bronchiectasis.
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PMID:Long-term ventilation in obstructive ventilatory disorders. 1260 13

Non-invasive positive pressure ventilation (NIPPV) has been discussed comprehensively in the last years, but usage of non-invasive ventilation in Intensive Care Units is rare. The reasons may be uncertainty in indications and difficulties in handling the masks and ventilators. In the last years the introduction of full face masks and respiratory helmets has made it possible to ventilate patients with unusual facial forms and to avoid problems of pressure necrosis. Software components designed for NIPPV are available for standard respirators. Indications for NIPPV (neuromuscular diseases, spinal abnormalities, chest wall malformations, COPD, cardiogenic pulmonary edema) have been ensured in clinical trials. No sufficient data are available for the application of NIPPV in weaning and respiratory failure following extubation. Indication for NIPPV becomes apparent when therapy starts in early stage with sufficient ventilation pressure. Compared to standard therapy, no reliable advantage has been seen for NIPPV in hypoxic hypercapnia respiratory failure except for malignant diseases. However, prophylactic use in patients with high risk might be conceivable. For these patients strict criteria of termination are required to avoid missing the time point for intubation. Gas exchange disturbances in advanced lung fibrosis, pneumonia and ARDS are not amenable to NIPPV. Contraindications for NIPPV are non-compliant patients, absence of cough- and pharyngeal reflexes as well as retention of secretions and malignant ventricular arrhythmia. Relative contraindications are catecholamine-dependent circulatory collapse and acute myocardial infarction, since sufficient data for NIPPV are missing.
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PMID:[Noninvasive ventilation in the intensive care unit -- is it still negligible?]. 1267 84

Chronic obstructive lung diseases (COPD) are a complex disease state which not rarely can be associated with significant systemic manifestations. These alterations, though recognized since long time, are currently under extensive research, due to the increasing appreciation of their relevant negative role in the prognosis and health-related quality of life (Hr-QoL) of the COPD patients. The most clinically important are the decrease in body weight with loss of skeletal muscle mass (cachexia), osteoporosis, hypercapnia-induced peripheral edema, neuro-psychiatric disorders, such as oxygen-related cognitive impairment and depression, excessive polycytaemia and sleep disorders. Chronic systemic inflammation, oxidative stress and chronic hypoxia are believed as the main factors involved in the pathogenesis of systemic effects seen in COPD. Their adequate control with nutritional support, change of life-style and targeted pharmacological treatment is able to improve the prognosis and Hr-QoL among these COPD patients.
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PMID:[Chronic obstructive lung disease. Systemic manifestations]. 1272 1

Noninvasive positive-pressure ventilation (NPPV) should be considered a standard of care to treat COPD exacerbations in selected patients, because NPPV markedly reduces the need for intubation and improves outcomes, including lowering complication and mortality rates and shortening hospital stay. Weaker evidence indicates that NPPV is beneficial for COPD patients suffering respiratory failure precipitated by superimposed pneumonia or postoperative complications, to allow earlier extubation, to avoid re-intubation in patients who fail extubation, or to assist do-not-intubate patients. NPPV patient-selection guidelines help to identify patients who need ventilatory assistance and exclude patients who are too ill to safely use NPPV. Predictors of success with NPPV for COPD exacerbations have been identified and include patient cooperativeness, ability to protect the airway, acuteness of illness not too severe, and a good initial response (within first 1-2 h of NPPV). In applying NPPV, the clinician must pay attention to patient comfort, mask fit and air leak, patient-ventilator synchrony, sternocleidomastoid muscle activity, vital signs, hours of NPPV use, problems with patient adaptation to NPPV (eg, nasal congestion, dryness, gastric insufflation, conjunctival irritation, inability to sleep), symptoms (eg, dyspnea, fatigue, morning headache, hypersomnolence), and gas exchange while awake and asleep. For severe stable COPD, preliminary evidence suggests that NPPV might improve daytime and nocturnal gas exchange, increase sleep duration, improve quality of life, and possibly reduce the need for hospitalization, but further study is needed. There is consensus, but without strong supportive evidence, that COPD patients who have substantial daytime hypercapnia and superimposed nocturnal hypoventilation are the most likely to benefit from NPPV. Adherence to NPPV is problematic among patients with severe stable COPD.
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PMID:Noninvasive ventilation for chronic obstructive pulmonary disease. 1473 24

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.
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PMID:Hypoxia and hypercapnia affect contractile and histological properties of rat diaphragm and hind limb muscles. 1517 12

Noninvasive positive pressure ventilation in patients with stable chronic obstructive pulmonary disease. The role of non-invasive positive pressure ventilation (NIPPV) is well documented in patients with restrictive thoracic diseases like kyphoscoliosis, tuberculosis sequelae or neuromuscular disease. There is also a good evidence for the use of NIPPV in acute respiratory failure in patients with an exacerbation of COPD. The application of NIPPV in patients with chronic respiratory failure is growing, but there is less evidence than in restrictive disorders. NIPPV can unload the respiratory muscles in patients with chronic hypercapnic COPD and so alleviates fatigue of the respiratory pump, but improvement in the maximal inspiratory pressure (Pi (max)) is small or even absent. An improvement of sleep quality has also postulated, there was an increase in total sleep time and sleep effectiveness when using higher inspiratory pressure. An increase of the walking distance was shown in short term studies, only. In most studies, there was an increase in quality of life as a main topic. Mortality was unchanged in the two long-term randomised controlled studies. Current data suggest a possible role of NIPPV in patients with severe hypercapnia. A high effective inspiratory pressure and a ventilator mode with a significant reduction in the work of breathing should be choosen. NIPPV should be started in hospital, a close reassessment must be performed. Patients who accepted NIPPV in the first weeks had a good compliance for long-term use.
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PMID:[Noninvasive mechanical ventilation in patients with stable severe COPD]. 1521 36

We studied the clinical features and efficacy of home noninvasive positive pressure ventilation (NPPV) therapy in 80 patients to ascertain its indications and problems. The causes of chronic respiratory failure were restrictive thoracic diseases of post-tuberculosis sequelae (40 cases) and kyphoscoliosis (9 cases), COPD (8 cases), bronchiectasis (7 cases), and interstitial pneumonia (4 cases). One year survival rate of the patients with post-tuberculosis sequelae was 76% and most of the patients who started NPPV at their acute exacerbation died within several months. About half of the patients of COPD improved their quality of life (QOL) through NPPV. However, their survival rate 3 months later was only 69%. More than half of the patients with bronchiectasis felt that their QOL was improved by NPPV. Most of the patients with interstitial pneumonia died within 3 months indicating that NPPV is less useful for improving QOL of interstitial pneumonia PaCO2, after home NPPV, decreased significantly in the responder group (70.0 +/- 15.4 vs. 57.6 +/- 10.7[SD]Torr, p < 0.05), while PaCO2 in the non-responder group was unchanged (65.4 +/- 12.1 vs. 64.2 - 10.4 [SD] Torr). Body Mass Index (BMI) in the responder group tended to be higher than in the non-responder group. In conclusion, the restrictive thoracic diseases with post-tuberculosis sequelae and kyphoscoliosis are a good indication for NPPV and the therapy is also useful for patients with bronchiectasis who can dispose of their sputum by themselves. Home NPPV is suitable for patients whose PaCO2 decreases through NPPV and whose BMI is relatively high. QOL of interstitial pneumonia barely improves through NPPV, because interstitial pneumonia with hypercapnia is at the terminal stage.
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PMID:[Eighty cases of chronic respiratory failure treated with home noninvasive positive pressure ventilation]. 1570 46

Acute dyspnea represents a diagnostic challenge even for the experienced physician. There are no prospectively evaluated diagnostic algorithms dealing with this frequent clinical problem. First of all, the emergency has to be assessed and life supporting measures have to be considered. In addition to a thorough medical history and clinical examination, chest X-ray, spirometry, ECG, hemoglobin measurement, BNP and D-dimer testing represent valuable diagnostic tools and are available to GP's. Most commonly, acute dyspnoea is pulmonary or cardiac in origin. Up to one third of all cases will have several causes. Functional dyspnea is difficult to diagnose but should be taken into consideration after excluding any somatic cause. Hyperventilation is found in both, organic and non organic diseases, and is therefore an inappropriate criterion to differentiate between the two. The mainstay in the management of any symptom is to primarily treat the underlying disease. A significant hypoxemia (SO2 < 90%, pO2 < 60 mmHg) ought to be corrected by supplemental oxygen. It is inappropriate to withhold oxygen from patients with COPD and severe hypoxemia just to avoid hypercapnia. Besides oxygen, opiates efficiently relief dyspnoea but harbour the risk of respiratory depression, altered mental status or aspiration.
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PMID:[Acute dyspnea--what should I not forget?]. 1599 36

Understanding the respiratory control system and the ventilatory pattern under hypercapnic stimulus is important to interpret the acute exacerbation of COPD and the condition of patients connected to mechanical ventilation. The purpose of this study is the analysis of respiratory and muscle parameters in order to obtain the most sensitive and characteristic of different levels of hypercapnic stimulus. Parameters defined and calculated from pressure signals show the highest variations with the increment of stimulus. Other ones like exhaled ventilation or ratios between respiratory parameters are more influenced by hypercapnia than tidal volume, respiratory frequency or even end tidal CO2. Muscle parameters from electromyographic signals of three respiratory muscles are calculated in time and frequency domain. In spite of greater variability between subjects, the most interesting muscles because of their activation with higher stimulus are in the following order: diaphragm, sternomastoid and genioglossus. Moreover, a model of respiratory control system is evaluated in order to predict and simulate appropriately this ventilatory stimulus. In spite of scattered real data, they are compared with simulation results obtained by the model and predicted by means of a specific respiratory optimization.
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PMID:Modeling and evaluation of respiratory and muscle pattern during hypercapnic stimulus. 1727 Nov 52

This short review summarizes a series of studies on the effects of expiratory flow limitation (EFL) at approximately 1 L/s during incremental exercise to maximal workload (Wmax) in normal subjects on exercise performance, respiratory muscle dynamics and control, and CO(2) elimination. Each subject served as his or her own control by performing the same protocol without EFL. Additionally, an index of cardiac output was measured before and after imposing EFL while the subjects exercised at Wmax, Wmax was reduced to 65% of control by severe dyspnoea. EFL forced a decrease in the shortening velocity of expiratory muscles, resulting in increased expiratory pressures which accounted for 66% of the variance in Borg scale ratings of dyspnoea. In spite of an increase in the shortening velocity of inspiratory muscles, inspiratory pressures and power increased, because EFL exercise induced hypercapnia, which increased the chemical drive to breathe. This was in part due to an increased alveolar dead space presumably resulting from a reduction in pulmonary capillary blood volume secondary to the high expiratory pressures. A vicious circle was established in which expiratory muscle pressures induced hypercapnia, which resulted in an even stronger expiratory muscle contraction. The imposition of EFL reduced cardiac output by 10% and decreased arterial O(2) saturation, reducing energy supplies to working locomotor and respiratory muscles. This model reproduces the most important clinical features of COPD, and these arise from ventilatory pump dysfunction rather than from the lung. It also leads to hypotheses that can be tested in patients with COPD.
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PMID:A human model of the pathophysiology of chronic obstructive pulmonary disease. 1758 12


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