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

We have developed a new O2 applicator to try to overcome the problems of long-term oxygen therapy that ensures a sufficient oxygen supply for both nasal and oral breathing and prevents mucosal irritation. Placed on the upper lip, it is unobtrusive. The principle is as follows: due to an enlarged outlet area, turbulence occurs and the oxygen is reduced. Thus, an oxygen cloud is formed that can be inhaled by both mouth or nose. The efficiency of our O2 applicator was compared with a face mask in six healthy subjects and patients with COPD. A similar increase in PO2 was found up to an oxygen flow of 2 L/min for nasal and oral breathing. Mild hypercapnia resulted in three patients with COPD only when a face mask was used and only when patients breathed through the nose. All patients preferred the new applicator.
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PMID:A new oxygen applicator for simultaneous mouth and nose breathing. 813 57

In acute respiratory failure interstitial oedema, alveolar collapse, and multiple atelectasis are the main mechanisms which lead to increased venous admixture and impaired oxygenation. Thus the lung volume available for pulmonary gas exchange is considerably reduced. Since there is strong evidence that alveolar overdistension causes lung damage ('barotrauma/volutrauma') large tidal volumes and high airway pressures in mechanical ventilation have to be strictly avoided, even allowing hypoventilation ('permissive hypercapnia'). Recruitment of the collapsed alveoli by external or intrinsic PEEP, or by changing body position, is often possible. However, alveolar recruitment takes much longer than previously assumed: instead of occurring within one respiratory cycle ('inflection point'), it seems to take hours. This slow recruitment process can be effectively supported by a deliberate use of intrinsic PEEP as with inverse ratio ventilation, either in volume or pressure controlled mode. Assisted spontaneous breathing makes ventilatory support less invasive and offers considerable advantages for many patients, but there are still some restrictions. Individual adaptation may be difficult in some patients. New principles of assistance control ('proportional assist ventilation') may improve individual adaptation. New concepts for weaning in COPD patients seem to offer better clinical strategies.
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PMID:Artificial ventilation: some unresolved problems. 814 15

The mechanisms of chronic ventilatory failure in chronic obstructive pulmonary disease are complex. This paper analyses the diverse available information: mechanical factors and gas-exchange, fighter vs. non-fighter, the ventilatory pattern theory and the fatigue threshold theory. Finally we comment on the evidence supporting the new concept that hypercapnia may develop to avoid or prevent fatigue. Indeed, it is very likely that chronic CO2 retention in COPD may develop by mechanical disadvantages of the inspiratory muscles rather than impairment of ventilation-perfusion ratios. This opens a fascinating new research line on the neuromechanical control of breathing. When the respiratory effort is approaching the fatigue level, the respiratory muscles may elicit a negative feedback reflex, the muscle activity is depressed and hypercapnia develops. If this is so, chronic hypercapnia may be an index of imminent fatigue if increases in ventilation or work of breathing are required. Under this condition some degree of central diaphragm fatigue may help to protect the muscle from severe or limiting peripheral fatigue or even muscle injury. Finally, we comment on some therapeutic approaches such as ventilatory stimulants, training, rest and, specially, oxygen administration and the mechanisms involved in the PCO2 increases.
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PMID:[Causes of CO2 retention in patients with chronic obstructive lung disease]. 820 18

Six patients with chronic respiratory failure associated with hypercapnia were treated with nasal intermittent positive pressure ventilation (NIPPV) at home. NIPPV was delivered via a custom molded nasal interface described by McDermott. The patients consisted of one patient with kyphoscoliosis, three with Tb-sequela, one with COPD, and one with neuromuscular disease. Each patient had been treated with oxygen therapy until assisted ventilation was initiated because of CO2 retention. NIPPV was administered using a volume cycled flow generator set to deliver a minute volume such that PaCO2 was maintained between 35 and 45 Torr on NIPPV trial performed during wakefulness under the condition of no leakage from the mask. Supplementary oxygen was added so that oxygen saturation was maintained above 90 percent during more than 95% of nighttime NIPPV. Arterial blood gas tensions during daytime spontaneous breathing showed an improvement (PaCO2 68.3 +/- 7.2 Torr, PaO2 70.4 +/- 15.5 Torr, SaO2 91.6 +/- 4.3% before treatment; PaCO2 55.8 +/- 4.7 Torr, PaO2 87.5 +/- 16.5 Torr, SaO2 95.5 +/- 1.7% on treatment, mean +/- SD). The duration of NIPPV at home ranged from 2 to 24 months (11.7 +/- 6.8), and there was no hospitalization due to exacerbation during this period. In conclusion, NIPPV via a custom molded mask is simple, noninvasive, and suitable for the provision of long-term and domiciliary assisted ventilation.
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PMID:[Long-term artificial ventilation by nasal intermittent positive pressure ventilation; 6 cases of domiciliary assisted ventilation]. 827 6

We describe the clinical, radiologic, functional, and pulmonary hemodynamic characteristics of a group of 30 nonsmoking patients with a lung disease that may be related to intense, long-standing indoor wood-smoke exposure. The endoscopic and some of the pathologic findings are also presented. Intense and prolonged wood-smoke inhalation may produce a chronic pulmonary disease that is similar in many aspects to other forms of inorganic dust-exposure interstitial lung disease. It affects mostly country women in their 60s, and severe dyspnea and cough are the outstanding complaints. The chest roentgenograms show a diffuse, bilateral, reticulonodular pattern, combined with normalized or hyperinflated lungs, as well as indirect signs of pulmonary arterial hypertension (PAH). On the pulmonary function test the patients show a mixed restrictive-obstructive pattern with severe hypoxemia and variable degrees of hypercapnia. Endoscopic findings are those of acute and chronic bronchitis and intense anthracotic staining of the airways appears to be quite characteristic. Fibrous and inflammatory focal thickening of the alveolar septa as well as diffuse parenchymal anthracotic deposits are the most prominent pathologic findings, although inflammatory changes of the bronchial epithelium are also present. The patients had severe PAH in which, as in other chronic lung diseases, chronic alveolar hypoxia may play the main pathogenetic role. However, PAH in wood-smoke inhalation-associated lung disease (WSIALD) appears to be more severe than in other forms of interstitial lung disease and tobacco-related COPD. The patients we studied are a selected group and they may represent one end of the spectrum of the WSIALD.
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PMID:Pulmonary arterial hypertension and cor pulmonale associated with chronic domestic woodsmoke inhalation. 841 64

The most frequent form of lung emphysema leading to respiratory failure is the tobacco bronchitis-induced type of emphysema the so called chronic obstructive pulmonary (lung) disease (COPD). Histologically the centrilobular or centriacinar emphysema is believed to develop due to elastase and oxidant overload with concomitant antiprotease deficiency. The alpha1-antitrypsin deficiency is a rare genetic defect leading also in non-smoking patients to early death due to panlobular or panacinar emphysema. The functional pattern of both emphysema types shows irreversible lung overinflation with severe mainly expiratory bronchial obstruction with various degrees of pulmonary hypertension alpha1-proteinaseNinhibitor deficiency emphysema is prophylactically treated with prolastine and if hypoxia (PaO2 > 55 mm/Hg) is present with long term oxygen therapy. If hypercapnia develops O2 Therapy is combined with non invasive pressure supported ventilation. Volume reducing surgery may precede. In nonsmoking emphysema patients long term oxygen therapy and later unilateral lung transplantation improves quality of life as well as life expectancy.
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PMID:[Pulmonary emphysema--lung transplantation]. 857 95

Our study suggests that the administration of bronchodilator drug via nebulizer powered by flow rate 6 L/min is more suitable in COPD patients. The oxygen flow rates should not be given more than 6 L/min. In this study, we recruited COPD patients in a stable stage, in whom the risk of hyperoxic induced hypercarbia is less than in the acute exacerbation stage. Thus, in acute exacerbation stage of the COPD patients, the rise of carbondioxide should be higher. We recommend that the COPD patients should receive bronchodilator drug via the nebulizer, especially in acute exacerbation stage, with oxygen flow rate not more than 6 L/min. The medical personnel must closely observe the clinical signs of the patients to prevent the hazard of carbondioxide retention.
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PMID:Is driving oxygen flow rate clinically important for nebulizer therapy in patients with COPD? 886 11

The purpose of the lung is intrapulmonary gas exchange. The circulatory system delivers the respiratory gases to the tissue. The ventilatory pump however is responsible for the circulation of air between the lungs and the ambient atmosphere. Due to better diffusing capabilities, hypercapnia always is a result of pump failure and little dependent on the lung. Ventilatory failure, either compensated with an increased demand on the muscles or decompensated with an additional increase in pCO2, should be separated from lung failure where primarily oxygen exchange is involved. Decompensated hypercapnic ventilatory failure is then the indication for intermittent mechanical ventilation. The pCO2, either arterial or transcutaneously registered together with the noninvasive evaluation of the mouth occlusion pressures during tidal breathing and during a maximal inspiratory effort, define well the severity of ventilatory failure. In acute on chronic ventilatory failure, noninvasive mechanical ventilation in three randomised and controlled studies resulted in a better survival compared to intubation. To fulfil certain weaning criteria is no longer required in difficult to wean patients, as a transfer from invasive to noninvasive mechanical ventilation can be performed if only cooperativity is preserved together with a minimal capacity of spontaneous breathing. Weaning will thereafter occur by progressive relief from intermittent noninvasive ventilation. 2300 difficult to wean patients in Germany should profit from this approach. Chronic ventilatory failure as a result of neuromuscular disease or scoliosis of the thoracic spine are the classical indications. COPD and myasthenia gravis are under discussion as indications for intermittent mechanical ventilation with an increasing tendency to ventilate. Epidemiological data however can only be roughly estimated due to the heterogeneity of indication and selection of the patients.
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PMID:[Epidemiology and diagnosis of intermittent self-ventilation]. 923 70

We sought to determine if predicted post-operative maximal oxygen uptake (VO2max/kg-PPO) was associated to the occurrence of respiratory or cardiac failure within the 60 days following lung surgery and to evaluate its validity as operability criterion. We studied 47 patients with chronic air-flow limitation (COPD) with FEV1 > 0.8 1 and without hypercapnia, that underwent lung surgery. Age was 56 (SD 11) years, FEV1 = 1.8 (SD 0.5) 1 (61% predicted (SD 13%) and FEV1/FVC = 55 (SD 7.5). Ten patients presented serious cardiac or respiratory complications (3 died). Significant correlation with complications was found for RV, TL-COsb-PPO, VO2max/kg, resection size and VO2max/kg-PPO. VO2max/kg-PPO correlation (-0.73) was significantly higher (p = 0.0016) than all the pulmonary function test (PFT) correlation and than VO2max/kg correlation (p = 0.049) as well. Cut-off points, positive and negative predictive values were respectively: 12.6 ml/min/kg, 0.75 y 0.90% for VO2max/kg-PPO; 17 ml/min/kg 0.83 and 0.87 for VO2max/kg and 148%, 0.67 and 0.82 for RV (the best of the pulmonary function tests). Multivariable models did not improve discriminant power. We conclude that, out of the studied variables, VO2max/kg-PPO showed higher correlation with the complications sought than PFT or VO2max/kg. As criterion to predict cardiac or respiratory failure, with the observed prevalence, its negative predictive values is good, but its positive predictive value is relatively low. None parameter was able to predict all the complications.
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PMID:[Role of postoperative estimate of maximum oxygen uptake in predicting cardiorespiratory insufficiency in the immediate postoperative period in thoracic surgery]. 961 37

COPD is an extremely common, chronic disorder characterized by a reduction in airflow after the administration of an inhaled bronchodilator as measured by the FEV1. The diagnosis is suspected in patients with a history of several decades of cigarette smoking who present with nonspecific respiratory symptoms. The diagnosis is established by simple forced expiratory spirometry. Baseline evaluation usually includes a chest radiograph and some assessment of functional capacity, either by history or with some form of exercise testing. In patients whose initial FEV1 is more severely reduced or who have significant dyspnea, an arterial blood gas is indicated at baseline. Dyspnea, hypoxemia, or hypercarbia that is out of proportion to the measured FEV1, at either presentation or follow-up, should prompt a thorough evaluation for complicating conditions. There are important roles in health care delivery and chronic disease management strategies for RCPs, primary care providers, and specialty trained pulmonary physicians. The need for repeated, extensive, or expensive testing will be largely driven by patients symptoms but disease monitoring with periodic assessments of dyspnea, functional capacity, and spirometry can be performed without great expense.
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PMID:Diagnosing and monitoring the clinical course of chronic obstructive pulmonary disease. 977 Feb 58


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