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

Respiratory failure from causes exclusive of intrinsic lung disease is rare in systemic sclerosis. We report an unusual case of a young woman with diffuse systemic sclerosis who presented with proximal muscle weakness, dyspnea, weight loss, and nasal regurgitation. On physical examination, she had normal breath sounds but severe limitation of chest wall expansion. Pulmonary function tests (PFTs) were consistent with restrictive lung disease. Pulmonary pressures were normal on right heart catheterization and chest radiography and high-resolution computed tomography showed no evidence of intrinsic lung disease. Quadriceps muscle biopsy was consistent with type II atrophy, without any element of inflammatory myositis. After a meal, the patient aspirated, developed severe persistent hypercapnia, and required ventilatory support. Therapy with corticosteroids and intravenous gamma globulin failed to improve her condition, and the patient subsequently expired. Hypercapnic respiratory failure on the basis of chest wall involvement from systemic sclerosis may occur in the absence of intrinsic lung disease, and the prognosis, as in this case, may be grave.
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PMID:Hypercapnic respiratory failure in systemic sclerosis. 1704 22

Amyothrophic lateral sclerosis (ALS) is a progressive, lethal neuromuscular disease that is associated with the degeneration of cortical and spinal motoneurons, leading to atrophy of limb, axial, and respiratory muscles. Patients with ALS invariably develop respiratory muscle weakness and most die from pulmonary complications. Overexpression of superoxide dismutase 1 (SOD1) gene mutations in mice recapitulates several of the clinical and pathological characteristics of ALS and is therefore a valuable tool to study this disease. The present study is intended to evaluate an age-dependent progression of respiratory complications in SOD1(G93A) mutant mice. In each animal, baseline measurements of breathing pattern [i.e., breathing frequency and tidal volume (VT)], minute ventilation (VE), and metabolism (i.e., oxygen consumption and carbon dioxide production) were repeatedly sampled at variable time points between 10 and 20 wk of age with the use of whole-body plethysmographic chambers. To further characterize the neurodegeneration of breathing, VE was also measured during 5-min challenges of hypercapnia (5% CO(2)) and hypoxia (10% O(2)). At baseline, breathing characteristics and metabolism remained relatively unchanged from 10 to 14 wk of age. From 14 to 18 wk of age, there were significant (P < 0.05) increases in baseline VT, VE, and the ventilatory equivalent (VE/oxygen consumption). After 18 wk of age, there was a rapid decline in VE due to significant (P < 0.05) reductions in both breathing frequency and VT. Whereas little change in hypoxic VE responses occurred between 10 and 18 wk, hypercapnic VE responses were significantly (P < 0.05) elevated at 18 wk due to an augmented VT response. Like baseline breathing characteristics, hypercapnic VE responses also declined rapidly after 18 wk of age. The phenotypic profile of SOD1(G93A) mutant mice was apparently unique because similar changes in respiration and metabolism were not observed in SOD1 controls. The present results outline the magnitude and time course of respiratory complications in SOD1(G93A) mutant mice as the progression of disease occurs in this mouse model of ALS.
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PMID:Respiratory impairment in a mouse model of amyotrophic lateral sclerosis. 1711 May 20

Respiratory involvement is an almost constant feature of als, with a usually rapid progression leading to respiratory failure. These characteristics justify a close follow up, usually at three-month intervals. A systematic, careful clinical evaluation is essential to detect the subtle respiratory symptoms and signs related to respiratory muscle failure. Dyspnea and orthopnea are often late findings in patients with a usually severe functional impairment due to peripheral muscle weakness. Nocturnal respiratory events (obstructive sleep apnea syndrome and hypoventilation) are strongly suggested by daytime hypersomnolence and frequent morning headaches. Physical evaluation is essential to detect accessory muscle recruitment, supine abdominal paradox, and encumbrance of upper or lower airways. Vital capacity (VC) is the most classical lung function test. The major limitation of spirometry is its poor sensitivity to detect a moderate inspiratory muscle weakness. Supine VC may improve the detection of diaphragmatic involvement. Peak expiratory flow during cough (cough PEF) gives an overall evaluation of cough efficiency, values below 160 to 270 L/min suggesting poor airway clearance. Arterial blood gases are performed at first evaluation and subsequently in case of clinical signs, significant deterioration of lung function tests, or sleep desaturations. Hypercapnia is weakly related to lung function results in bulbar patients. A specific evaluation of respiratory muscle strength is mandatory, as these tests are both sensitive and highly prognostic. Possible discrepancies (particularly in bulbar patients) between Maximal inspiratory pressure (PImax) and sniff nasal inspiratory pressure (SNIP) justify to perform both measurements and to select the highest pressure. A maximal expiratory pressure (PEmax) below 45 cm H2O may indicate a compromised cough efficiency but the correlation with cough PEF may be poor. Screening nocturnal oxymetry is useful to detect sleep apneas and hypoventilation. Criteria defining significant desaturations remain however controversial. Suspicion of obstructive sleep apnea syndrome on clinical grounds or oxymetry findings should be confirmed by a conventional polysomnography.
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PMID:[Amyotrophic lateral sclerosis (ALS): evaluation of respiratory function]. 1712 9

Respiratory muscle weakness represents the major cause of mortality in patients with amyotrophic lateral sclerosis (ALS). As a result, ventilatory assistance is an important part of disease management. Nowadays, noninvasive ventilation (NIV) has become the first choice modality for most patients and represents an alternative to tracheostomy intermittent positive-pressure ventilation. Although, some consensus guidelines have been proposed to initiate NIV in patients with restrictive chronic respiratory failure, these criteria are discussed regarding ALS. While the current consensus recommends that NIV may be used in symptomatic patients with hypercapnia or forced vital capacity<50p.cent of predicted value, early use of NIV is proposed in the literature and reported in this paper.
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PMID:[Types of ventilatory support and their indications in amyotrophic lateral sclerosis]. 1712 21

Rigid spine syndrome (RSS) is a group of childhood-onset muscle disorders characterized by marked limitation of flexion of the spine. Various cardiac changes have been documented in case reports. This study reports on a cardiac evaluation of nine patients with the "vacuolar variant" of RSS. Noninvasive cardiac evaluation entailed creatine kinase levels, full-inspiration chest roentgenograms, standard 12-lead ECG, and 24-h ambulatory ECG recording, as well as M-mode and two-dimensional echocardiography with Doppler study. Heart auscultation was abnormal in five patients. Creatine kinase MB fraction was normal in all patients. Chest roentgenogram showed scoliosis (five of nine), kyphosis (one of nine), severe anterior-posterior flattening of the chest cavity (two of nine), elevated hemidiaphragm (one of nine), caved-in appearance of upper lobes (two of nine), and symmetry of lung volumes (one of nine). Twelve-lead ECG abnormalities indicated right-sided heart disease (three of nine). Echocardiogram showed mitral valve prolapse (five of nine) with regurgitation (three of five) and evidence of pulmonary hypertension (three of nine). Ambulatory ECG recorded paroxysmal tachyarrhythmias in hypoxic or hypercapnic patients (three of nine). There was no correlation between any cardiac abnormalities and patient weakness. Mitral prolapse/regurgitation may have a developmental association with this congenital myopathy. Findings of cor pulmonale were due to the restrictive chest wall defect and respiratory muscle weakness. Paroxysmal tachyarrhythmias were due to hypoxia or hypercapnia. There was no evidence of a primary cardiomyopathy.
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PMID:Rigid spine syndrome: a noninvasive cardiac evaluation. 1782 62

COPD is a disease that is not confined to the airways and the lungs, but also produces systemic consequences. Muscle weakness is one of these. It is produced by a multitude of factors including deconditioning, systemic inflammation, oxidative stress, nutritional imbalance, reduced anabolic status, systemic corticosteroids, hypoxemia, hypercapnia, electrolyte disturbances, cardiac failure. The most important factors appear to be inactivity and systemic inflammation. Inactivity was shown to be present in patients with COPD from early in the course of the disease on. Systemic inflammation was shown to be predominantly present during COPD exacerbations. IL-6 has the propensity to reduce muscle function in experimental animals. At present there is no evidence of local production of cytokines in the muscle in patients with COPD. Muscle weakness is also important in the clinical course of the disease as it is associated with exercise intolerance, reduced quality of life, enhanced utilization of health care resources and reduced survival. Rehabilitation is the best treatment for muscle weakness and deconditioning in patients with COPD. Indeed, it is the intervention with the largest effect on health status and exercise capacity in these patients. Several factors that may enhance the effects of rehabilitation have been studied. These include: growth hormone/ IGF-I, anabolic steroids, clenbuterol, creatine, anti-cytokine treatment, erythropoietin, oxygen, non-invasive mechanical ventilation and electrical stimulation. Recently, the potential of protease-inhibitors in reversing deconditioning-induced muscle dysfunction was demonstrated. Adjuncts are potentially particularly useful in patients who do not respond to a rehabilitation programme. Analysis of large d-bases demonstrated that about one third of the patients does not respond to rehabilitation. A follow-up study suggests that decline in exercise capacity after a rehabilitation programme is particularly present in these patients and not in the patients with a clear initial response. A better understanding of the factors controlling the response to rehabilitation, may lead to significant advances in this field.
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PMID:Pulmonary rehabilitation 2007: from bench to practice and back. 1898 Jul 25

A female in her late 60s with chronic kidney disease was admitted to the emergency department with complaints of dizziness four days prior to hospitalization. Cibenzoline (300 mg/day) was administered for atrial fibrillation, which was detected in an electrocardiogram. After three days, she experienced blepharoptosis and was admitted for suspected myasthenia gravis. However, the anti-acetylcholine receptor antibody and edrophonium tests were negative. On day four after hospitalization, she suffered from pneumonia with pleural effusion and she was put on a respirator for four days. From day 16 after hospitalization, she had diarrhea and her renal function worsened. At the same time, a gradual aggravation of right blepharoptosis, dull headache, weakness and difficulty in chewing were noted. She experienced dyspnea on day 31 after hospitalization. Chest X-ray film did not show a pneumonia shadow or pleural effusion, and arterial blood gases revealed hypercapnia; she was diagnosed as having CO2 narcosis due to respiratory muscle fatigue and was put on a respirator again. Myasthenia-like syndrome was suspected because of a probable overdose of cibenzoline and administration of cibenzoline was withdrawn. Her condition improved and she was taken off the respirator on day 35 after hospitalization. Repetitive stimulation of 5 Hz was applied to her right facial nerve along with evoked electromyogram(EMG) on days 2 and 11 after discontinuing cibenzoline. On day 2, the EMG showed a waning phenomenon, whereas no such phenomenon was seen on day 11. The blood concentration of cibenzoline immediately after withdrawal was extremely high (2448 ng/mL). When this drug is administered to a patient with chronic kidney disease, attention must be paid to the indication, dose, and manifestation of the possible side effects.
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PMID:[Myasthenia-like syndrome induced by cibenzoline overdose in a patient with chronic kidney disease]. 1906 53

Subjects with progressive neuromuscular diseases undergo a typical sequence of respiratory compromise, leading from normal unassisted gas exchange to nocturnal hypoventilation with normal daytime gas exchange, and eventually to respiratory failure requiring continuous ventilatory support. Several different abnormalities in respiratory pump function have been described to explain the development of respiratory failure in subjects with neuromuscular weakness. Early in the progression of respiratory failure, the use of nocturnal assisted ventilation can reverse both night- and day-time hypercapnia. Eventually, however, diurnal hypercapnia will persist despite correction of nocturnal hypoventilation. The likely beneficial effects of mechanical ventilatory support include resting fatigue-prone respiratory muscles and resetting of the central chemoreceptors to PaCO(2). Recent experience shows that select patients who require daytime ventilation can be supported with non-invasive ventilation continuously to correct gas exchange abnormalities while avoiding detrimental aspects of tracheostomy placement.
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PMID:Diurnal hypercapnia in patients with neuromuscular disease. 2011 85

A wide variety of mechanisms can lead to the hypoventilation associated with various medical disorders, including derangements in central ventilatory control, mechanical impediments to breathing, and abnormalities in gas exchange leading to increased dead space ventilation. The pathogenesis of hypercapnia in obesity hypoventilation syndrome remains somewhat obscure, although in many patients comorbid obstructive sleep apnea appears to play an important role. Hypoventilation in neurologic or neuromuscular disorders is primarily explained by weakness of respiratory muscles, although some central nervous system diseases may affect control of breathing. In other chest wall disorders, obstructive airways disease, and cystic fibrosis, much of the pathogenesis is explained by mechanical impediments to breathing, but an element of increased dead space ventilation also often occurs. Central alveolar hypoventilation syndrome involves a genetically determined defect in central respiratory control. Treatment in all of these disorders involves coordinated management of the primary disorder (when possible) and, increasingly, the use of noninvasive positive pressure ventilation.
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PMID:Hypoventilation syndromes. 2048 85

Sleep hypoventilation is seen in patients with neuromuscular disease, as well as in those with obesity hypoventilation syndrome (OHS), which is defined as the combination of obesity, chronic hypercapnia, and hypoxemia during wakefulness that is aggravated during sleep. In 90% of cases, OHS is accompanied by obstructive sleep apnea. The diagnosis of OHS is based on hypoventilation and pulmonary hypertension that cannot be explained by alterations in pulmonary function. The mortality of patients with OHS is greater than is that of obese patients without hypoventilation. The principal neuromuscular diseases associated with OHS are the muscular dystrophies. The progression to chronic respiratory failure results from respiratory muscle weakness and impaired airway secretion clearance, causing atelectasis and pneumonia. With a decrease of greater than 50% in respiratory muscle strength, there is a reduction in VC. Cough peak flow < 160 L/min is associated with impaired airway secretion clearance, and values near 270 L/min indicate the need for assisted cough techniques. Obstructive sleep apnea usually worsens sleep hypoventilation. Noninvasive ventilation during sleep can improve survival, symptoms, and hypoventilation during wakefulness, as well as being able to improve pulmonary function in patients with neuromuscular disease. Patients with OHS can require oxygen therapy.
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PMID:[Sleep hypoventilation]. 2094 82


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