Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0085383 (hypocapnia)
 1,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carbon dioxide is a waste product of aerobic cellular respiration in all aerobic life forms. PaCO2 represents the balance between the carbon dioxide produced and that eliminated. Hypocapnia remains a common - and generally underappreciated - component of many disease states, including early asthma, high-altitude pulmonary edema, and acute lung injury. Induction of hypocapnia remains a common, if controversial, practice in both adults and children with acute brain injury. In contrast, hypercapnia has traditionally been avoided in order to keep parameters normal. More recently, advances in our understanding of the role of excessive tidal volume has prompted clinicians to use ventilation strategies that result in hypercapnia. Consequently, hypercapnia has become increasingly prevalent in the critically ill patient. Hypercapnia may play a beneficial role in the pathogenesis of inflammation and tissue injury, but may hinder the host response to sepsis and reduce repair. In contrast, hypocapnia may be a pathogenic entity in the setting of critical illness. The present paper reviews the current clinical status of low and high PaCO2 in the critically ill patient, discusses the insights gained to date from studies of carbon dioxide, identifies key concerns regarding hypocapnia and hypercapnia, and considers the potential clinical implications for the management of patients with acute lung injury.
 ...
PMID:Bench-to-bedside review: carbon dioxide. 2049 20

Sustained or spontaneous hyperventilation has been associated with a variety of physical symptoms and has been linked to a number of organic illnesses and mental disorders. Theories of panic disorder hold that hyperventilation either produces feared symptoms of hypocapnia or protects against feared suffocation symptoms of hypercapnia. Although the evidence for both theories is inconclusive, findings from observational, experimental, and therapeutic studies suggest an important role of low carbon dioxide (CO2) levels in this disorder. Similarly, hypocapnia and associated hyperpnia are linked to bronchoconstriction, symptom exacerbation, and lower quality of life in patients with asthma. Raising CO2 levels by means of therapeutic capnometry has proven beneficial effects in both disorders, and the reversing of hyperventilation has emerged as a potent mediator for reductions in panic symptom severity and treatment success.
 ...
PMID:Hyperventilation in panic disorder and asthma: empirical evidence and clinical strategies. 2068 22

Bronchial asthma is a chronic inflammatory disorder of the airways in which many cells play a role, in particular mast cells, eosinophils, neutrophils, T-lymphocytes and epithelial cells. In susceptible individuals this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness and cough, particularly at night and/or in the early morning. These symptoms are usually associated with variable and extensive limitations of airflow in the bronchi reversible spontaneously or by treatment. It has been shown that restrain of the effectors of stress response participate in the pathogenesis of bronchial asthma. Anger that is not expressed and frustrations may activate the limbic stress pathway. Thus, the released neurotransmitters followed by excitation thus causing psychogenic (mental or emotional) stress. It is also known that emotional stress may be responsible for the exacerbation of asthma. Namely, pronounced emotions cause hyperventilation and hypocapnia inducing bronchospasm. Certain psychological personality features are related to adaptive or inadequate body response to numerous life events. Thus, until the beginning of the last century, bronchial asthma was referred to as asthma nervosa, because clinicians clearly observed the psychological profile of patients with predominant fear of asphyxia and recurrent attacks of paroxysmal dyspnoea. Besides, increased sensitivity, repression of aggressive feelings and expressive empathy have been identified as the most frequent psychological characteristics of asthmatic patients. However, scientists are still far from a full understanding of bronchial asthma pathogenesis. The contribution of psychic factors has become meaningful in the understanding of the development of bronchial asthma. Having in mind that in the majority of patients asthma is a lifelong condition, there is a hope that further investigations of bronchial asthma psychogenesis will improve prevention and treatment of this disease.
 ...
PMID:[The role of psychic factors in the pathogenesis of bronchial asthma]. 2162 67

Hypocapnia and hypercapnia constrict and relax airway smooth muscle, respectively, through pH- and calcium (Ca(2+))-mediated mechanisms. In this study we explore a potential role for the airway epithelium in these responses to carbon dioxide (CO(2)). Contractile and relaxant responses of isolated rat bronchial rings were measured under hypocapnic, eucapnic, and hypercapnic conditions. Substance P was added to methacholine precontracted bronchial rings with and without epithelium. The role of Ca(2+) was assessed using Ca(2+)-free solutions and a Ca(2+) channel blocker, nifedipine. The effects of pH were assessed in solutions with HEPES buffer. Hypocapnic challenge increased the organ bath's pH and increased bronchial smooth muscle resting tension. This effect was abolished with HEPES buffer and partially inhibited by nifedipine. Hypocapnic conditions suppressed substance P-induced epithelium-dependent relaxation, whereas hypercapnia augmented the response. The epithelial hypocapnic effect was pH dependent, whereas the hypercapnic effect was pH independent. CO(2) had no effect on the epithelial independent smooth muscle agonists methacholine and isoproterenol. In conclusion our data indicate that, in addition to the effects of pH and Ca(2+), CO(2) affects airway smooth muscle by a pH-independent, epithelium-mediated mechanism. These findings could potentially lead to new treatments for asthma involving CO(2)-sensing receptors in the airways.
 ...
PMID:Carbon dioxide enhances substance P-induced epithelium-dependent bronchial smooth muscle relaxation in Sprague-Dawley rats. 2181 29

Hyperventilation-induced hypocapnia is common among asthma patients. This case study illustrates both methodology and results from a patient undergoing training in capnometry-assisted respiratory training (CART). CART is a 4-week training aimed at normalizing basal and acute levels of end-tidal carbon dioxide (PCO(2)) using a portable capnometer. In the presented case, basal levels of PCO(2) increased from hypocapnic to normocapnic range over the course of treatment. Improvements were accompanied by improvements in lung function and reductions in diurnal lung function variability. Improvements remained stable throughout follow-up.
 ...
PMID:Hypoventilation training for asthma: a case illustration. 2221 May 21

We present a woman with heterozygous carnitine palmitoyl transferase 2 (CPT-2) deficiency who in the last 6 months suffered from episodic dyspnea and choking. Symptoms could not be attributed to her muscular energy defect, since heterozygous CPT-2 deficiency is usually asymptomatic or causes only mild muscle fatigability. Myopathy is usually triggered by concurrent factors, either genetic (additional muscle enzymes defects) or acquired (metabolic stress). The patient was referred to our respiratory clinic for suspect bronchial asthma. Spirometry showed mild decrease in inspiratory flows. Methacholine challenge was negative. Dyspnea was triggered by hyperventilation-induced hypocapnia, which produced marked decrease in airflow rates, particularly in inspiratory flows, consistent with laryngospasm. Nutritional assessment of the patient showed low serum level of calcium and vitamin D, attributable to avoidance of milk and dairy products for lactose intolerance and to insufficient sunlight exposure. After calcium and vitamin D supplementation episodic laryngospasm disappeared and hypocapnic hyperventilation test induced very mild change in airflow rates. Calcium and vitamin D deficiency may favour laryngeal spasm mimicking asthma, particularly in subjects with underlying myopathy.
Allergy Asthma Immunol Res 2014 May
PMID:Laryngeal spasm mimicking asthma and vitamin d deficiency. 2484 4

Paroxysmal Vocal Cords Dysfunction(PVCD), also known as paradoxical vocal cord motion, is abnormal adduction of the vocal cords during inspiration. Like asthma, PCVD can be triggered by breathing in lung irritants, upper respiratory infection or exercise. However, unlike asthma, PCVD is not an immune system reaction and does not involve the lower airways. Treatment for the two conditions differs. Plasma lactate levels are usually associated with acidosis and an increased risk of poor outcome and are described in a number of disease states of circulatory and/or respiratory failure. In patients with psychogenic hyperventilation, high lactates are associated with hypocapnia and alkalosis and should not necessarily be considered as an adverse sign. We describe a case of a young patient with PCVD mimicking asthma with high plasma lactate and discuss the mechanisms involved.
 ...
PMID:Hyperventilation-related hyperlactataemia in a case of paroxysmal vocal cord dysfunction. 2897 1

Asthma is a common illness throughout the world that affects the respiratory system function, i.e., a system whose operational adequacy determines the respiratory gases exchange. It is therefore expected that acute severe asthma will be associated with respiratory acid-base disorders. In addition, the resulting hypoxemia along with the circulatory compromise due to heart-lung interactions can reduce tissue oxygenation, with a particular impact on respiratory muscles that have increased energy needs due to the increased workload. Thus, anaerobic metabolism may ensue, leading to lactic acidosis. Additionally, chronic hypocapnia in asthma can cause a compensatory drop in plasma bicarbonate concentration, resulting in non-anion gap acidosis. Indeed, studies have shown that in acute severe asthma, metabolic acid-base disorders may occur, i.e., high anion gap or non-anion gap metabolic acidosis. This review briefly presents studies that have investigated acid-base disorders in asthma, with comments on their underlying pathophysiology.
 ...
PMID:Acid-Base Disturbances in Patients with Asthma: A Literature Review and Comments on Their Pathophysiology. 3102 65


<< Previous 1 2 3