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

Ten survivors of double lung transplantation using a tracheal anastomosis underwent assessment of their ventilatory responses to hypercapnia (HCVR) at least 3 months postsurgery. At the time of HCVR testing, pulmonary functions were normal in four and abnormal in six patients who demonstrated degrees of obstruction, restriction, or mixed defects. Arterial blood gas measurements were normal. Postoperatively, hypercapnic responses were low or low normal. Mean changes in tidal volume and mean change in respiratory frequency in response to hypercapnia postoperatively were not different in patients with normocapnic versus hypercapnic preoperative blood gases. Neither postoperative resting PCO2 nor muscle strength (as measured by MIP) were predictive of the degree or character of the patients' ventilatory responses to hypercapnia. The factors resulting in the observed blunting of the hypercapnic response in this denervated population require further clarification; however, comparison of data between this patient population and recipients of heart-lung transplantation reported elsewhere suggests that alterations in pulmonary function correlate with the observed depression in HCVR.
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PMID:Hypercapnic ventilatory response in recipients of double-lung transplants. 145 85

To ascertain whether and to what extent the reduced ventilatory response to a hypercapnic stimulus in chronic obstructive pulmonary disease (COPD) patients depends on a blunted chemoresponsiveness of central origin or to mechanical impairment, we studied two groups of COPD patients without (group A) and with (group B) chronic hypercapnia, but with similar degrees of airway obstruction and hyperinflation. The study was performed on 17 patients (9 normocapnic and 8 hypercapnic). Six age-matched normal subjects (group C) were also studied as a control. During a CO2 rebreathing test, ventilation (VE), mouth occlusion pressure (P0.1), and the electromyographic activity of diaphragm (Edi) were recorded and then plotted against end-tidal carbon dioxide tension (PCO2). Inspiratory muscle strength was significantly lower in the hypercapnic group (group B) compared to normocapnic group (A), and in these groups compared to the control group (C). Both patient groups exhibited significantly lower delta VE/delta PCO2 than the control group. In hypercapnics, delta P0.1/delta PCO2 was significantly lower than in normocapnics and control group, whilst mouth occlusion pressure as % of maximal inspiratory pressure delta P0.1 (% MIP)/delta PCO2 did not differ significantly among the three groups. delta Edi/delta PCO2 increased from C to A. At a PCO2 of 8.65 kPa, VE was similar in the normocapnic and control group, but lower in hypercapnics; Edi was similar in hypercapnic and control group; but greater in normocapnics. P0.1(% MIP) did not differ significantly among groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia. 774 98

Although ventilatory failure is the most common cause of death in amyotrophic lateral sclerosis (ALS) and measurement of respiratory muscle strength (RMS) has been shown to have prognostic value, no single test of strength can predict the presence of hypercapnia reliably. RMS was measured in 81 ALS patients to evaluate the relationship between tests of RMS and the presence of ventilatory failure, defined as a carbon dioxide tension > or = 6 kPa. We studied the predictive value of vital capacity (VC), static inspiratory and expiratory mouth pressures (MIP, MEP), maximal sniff oesophageal (sniff P(oes)), transdiaphragmatic (sniff P(di)) and nasal (SNP) pressure, cough gastric (cough P(gas)) pressure and transdiaphragmatic pressure after bilateral cervical magnetic phrenic nerve stimulation (CMS P(di)) to identify the risk of ventilatory failure in the whole group and in subgroups of patients with and without significant bulbar involvement. For patients without significant bulbar involvement, sniff P(di) had greatest predictive power [odds ratio (OR) 57] with specificity, sensitivity and positive and negative predictive values (PPV, NPV) of 87, 90, 74 and 95%, respectively Of the less invasive tests, per cent predicted SNP had greater overall predictive power (OR 25, specificity 85%, sensitivity 81%) than per cent predicted VC (9, 89%, 53%) and per cent predicted MIP (6, 83%, 55%). No test had significant predictive power for the presence of hypercapnia when used to measure RMS in a subgroup of patients with significant bulbar weakness. Thirty-five patients underwent polysomnography. CMS P(di), sniff P(di) and per cent predicted SNP were significantly correlated with the apnoea/hypopnoea index (AHI) (P = 0.035, 0.042 and 0.026, respectively). The correlations between AHI and per cent predicted MIP and VC were less strong (both non-significant). In ALS patients without significant bulbar involvement, novel tests of RMS have greater predictive power than conventional tests to predict hypercapnia. In particular, the non-invasive SNP is more sensitive than VC and MIP, suggesting that it could usefully be included in tests of respiratory muscle strength in ALS and will be helpful in assessing the risk of ventilatory failure. In patients with significant bulbar involvement, tests of respiratory muscle strength do not predict hypercapnia. Sleep-disordered breathing is correlated with RMS and the novel tests of RMS having the strongest relationship with the degree of sleep disturbance.
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PMID:Respiratory muscle strength and ventilatory failure in amyotrophic lateral sclerosis. 1157 Dec 18