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)

The alveolar to arterial oxygen pressure difference (AaDO2) and pulmonary venous admixture (Qs/Qt) were measured in 32 patients with chronic obstructive pulmonary disease during right heart catheterization at inspired oxygen concentrations (FIO2) of 21, 24, 28, 35, and 40%. Patients without chronic hypercapnia (PaCO2 is less than 45 torr, group A) had Qs/Qt less than 25% while breathing room air; their AaDO2 rose at a rate of 3 torr for each percent increase in FIO2. In those with chronic hypercapnia (PaCO2 greater than 44 torr., (group B), THE Qs/Qt was always greater than 24% during air breathing and the AaDO2 rose at a rate of 5 torr for each percentage increase in FIO2. These changes should be considered in the interpretation of the AaDO2 in patients with COPD in whom the FIO2 is changed during the course of therapy. The Qs/Qt fell curvilinearly with increasing FIO2 but the rates of fall were quantitatively different in groups A and B. A physiological explanation for the changes in Qs/Qt and ADO2 which result from changes in FIO2 is presented.
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PMID:The AaDO2 and venous admixture at varying inspired oxygen concentrations in chronic obstructive pulmonary disease. 65 13

Digoxin-like immunoreactive factor (DLIF) is an endogenous substance with natriuretic and diuretic activity. Elevated plasma levels of DLIF are found in various clinical states characterized by water and sodium retention. Chronic respiratory failure, particularly of an advanced stage, also is frequently associated with water and sodium retention. In order to determine whether elevated plasma levels of DLIF are present in chronic respiratory failure, we measured plasma DLIF levels in seven patients (four with COPD [two of whom had associated sleep apnea disturbance] and three with kyphoscoliosis) suffering from advanced chronic respiratory failure with severe hypoxemia and hypercapnia. We found that in these patients plasma levels of DLIF were significantly higher than in healthy control subjects. We conclude that patients with advanced chronic respiratory failure respond with increased levels of DLIF. This may represent an attempt at homeostasis of water and sodium metabolism which is frequently deranged in this clinical condition.
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PMID:Endogenous digoxin-like immunoreactive factor is elevated in advanced chronic respiratory failure. 130 96

With the objective to test the effect of intermittent and short term rest in respiratory muscles in patients with COPD and maintained hypercapnia we have studied 34 patients in a stable condition: 23 were part of the study group (Group I) and 11 were the control group (Group II). After a complete functional basal study, patients in Group I were treated with intermittent rest of their respiratory muscles, through a negative pressure external respirator--shield type--during three consecutive days. We got, in this study group, a significative improvement in the maximum inspiratory pressure measured at residual volume (PI max RV), which went from 66.6 +/- 15.9 to 71.2 +/- 15.2 (p < 0.005), as well as a lowering, also significative, of partial pressure of CO2 in arterial blood (PaCO2) and in expired air (EFCO2), which went from 55.2 +/- 7.2 to 52.3 +/- 3 (p < 0.0002) and 3.3 +/- 0.5 to 3.1 +/- 0.5 (p < 0.01), respectively. Maximum inspiratory pressure measured to functional residual capacity (PI max FRC) experienced an increase in the limit of statistical signification. Rest of the parameters did not significantly change. These results back the hypothesis that in stabilized COPD with CO2 retention, a chronic fatigue of respiratory muscles could exist, and that intermittent rest of these muscles could mean an hypercapnia diminution, due to the improvement in the function of respiratory muscles.
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PMID:[Short-term effects of respiration with external negative ventilation --shield-type respirator-- on the pulmonary function in COPD]. 833 62

Failure of weaning from mechanical ventilation in COPD patients is often related to diaphragmatic fatigue. Whether there is a central respiratory drive fatigue and a reserve of excitability is still debated. The purpose of this study was to analyze the following in 13 COPD patients weaned from mechanical ventilation: (1) ventilatory (VE/PETCO2) and neuromuscular (P0.1/PETCO2) response to hypercapnia; (2) the maximum reserve capacity measured through changes in the VE/PETCO2 and P0.1/PETCO2 slopes after doxapram (DXP) infusion, which, given during the test, allows measurement of the maximum response capacity to overstimulation; and (3) analyze the influence of these changes on the outcome of weaning. The results show a variable P0.1/PETCO2 response and a low VE/PETCO2. DXP infusion does not change the slopes of these relations but increases the end-expiratory volume (delta FRCd); (p less than 0.02). Since there was no change in the VE/PETCO2, P0.1/PETCO2, and delta FRC values with or without DXP, there was no excitability reserve in patients who were successfully weaned. When weaning failed, DXP did not change VE/PETCO2 and P0.1/PETCO2 slope, but delta FRCd was greater the delta FRC (p less than 0.001). The excitability reserve in these patients leads to an increase in end-expiratory volume, probably worsening the diaphragm dysfunction.
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PMID:Effects of doxapram on hypercapnic response during weaning from mechanical ventilation in COPD patients. 160 Jul 86

We assessed ventricular performance during exercise in 16 COPD patients and 8 normal control subjects by means of radionuclide equilibrium angiography using technetium-99m as a tracer. Supine exercise on a bicycle ergometer was performed until symptom-limited exhaustion. Data were accumulated for 300 heart beats at rest and 150 heart beats during exercise. We used the standard voxel count method to calculate the ventricular volumes. Age, FEV1.0%, %VC, PaO2 and PaCO2 of the COPD patients were 63 +/- 8 yr, 46 +/- 11%, 69 +/- 18%, 68 +/- 11 Torr and 44 +/- 7 Torr (mean +/- SD), respectively. Systolic dysfunction of both the left and right ventricles was well confirmed in the present study. In 12 patients who also underwent hemodynamic studies, resting total pulmonary vascular resistance index (TPVRI) and mean pulmonary artery pressure (Ppa) significantly correlated with right ventricular end-systolic volume index (RVESVI) obtained by RI angiography; gamma = 0.769 (p less than 0.01) and gamma = 0.631 (p less than 0.05), respectively. A significant relationship was also observed between left ventricular dysfunction and the degree of hypercapnia. In response to exercise testing, 10 of 16 patients exhibited insufficient augmentation of stroke volume, and both left and right end-diastolic volumes decreased in half of 10 patients. It is suggested that cardiac function may be disturbed by mechanical factors such as pulmonary hyperinflation in COPD patients.
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PMID:[Ventricular performance during exercise in patients with chronic obstructive pulmonary disease (COPD)]. 162 97

We evaluated the physiologic effects of pressure support ventilation by nasal route (NPSV) in eight patients with severe stable COPD and chronic hypercapnia who were randomly submitted to 2-h sessions of NPSV both with a portable ventilator (Respironics BIPAP device) and with a standard ventilator (Bird 6400ST device) at an inspiratory airway pressure of 22 cm H2O. Two sessions with each ventilator were performed using an FIO2 of 0.21 in each patient on two consecutive days. One patient did not tolerate either form of ventilation. Comparison of spontaneous with BIPAP ventilation showed a significant improvement in pH, PaCO2, and PaO2. Ventilatory pattern assessed by a respiratory inductive plethysmograph showed a significant increase in minute ventilation (VE), VT, and Ttot. Integrated surface diaphragmatic EMG activity measured only during BIPAP device ventilation decreased from that measured during spontaneous breathing. Similar changes in blood gases and ventilatory pattern were observed during ventilation by the Bird 6400ST except for VT/Ti ratio, which significantly increased. Comparison of baseline with measurements performed 12 h after the whole cycle of treatment showed a significant increase in pH and VE and a decrease in PaCO2. We conclude that short-term NPSV may be useful in improving respiratory pattern and blood gases in stable COPD patients with chronic hypercapnia.
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PMID:Physiologic evaluation of pressure support ventilation by nasal mask in patients with stable COPD. 173 60

Twenty eight COPD patients with respiratory insufficiency were studied. These included: 12 hypoxemic and normocapnic patients, 16 hypoxemic and hypercapnic patients, and 22 healthy volunteers. During at rest respiration both COPD groups differed from the control group--demonstrating a higher respiratory incidence, VT/Ti and PO2 values. During hypercapnic stimulation using the rebreathing method the ventilatory response to CO2 in the COPD patients was lowered in comparison with the control. Increase of occlusion pressure as a response to the increasing hypercapnia was lowered in both groups, significantly in patients with hypercapnia.
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PMID:[Control of respiration in patients with respiratory insufficiency in chronic obstructive lung disease]. 184 96

We report a patient with COPD and bullous emphysema treated with narcotic antagonists (naloxone and naltrexone) for severe respiratory failure, with hypoxemia and hypercapnia, non responding to traditional medical therapy. According to previous reports, this treatment was started while waiting for lung transplantation, and it improved clinical pattern and arterial blood gas levels. Though the patient died for left ventricular failure fifteen days after the beginning of therapy, we think that narcotic antagonists can be successfully administered in some patients with advanced stage COPD.
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PMID:[Naloxone and naltrexone in the therapy of advanced COPD]. 185 43

Intermittent mechanical ventilation via nasal CPAP mask was provided to 13 patients admitted to this institution for exacerbation of chronic respiratory failure. Ten suffered from COPD, two suffered from obesity hypoventilation syndrome (OHS), and one from severe hypothyroidism. All except one presented with dyspnea and hypercapnia due solely to progression of their underlying disease processes. Six of the patients with COPD and the patient with hypothyroidism responded to positive pressure ventilation by mask with improvements in blood gas values and clinical status. The remaining two patients with COPD and the two patients with OHS were unable to use the system. Four of the patients with COPD and chronic respiratory failure have been subsequently maintained on daily volume ventilation via nasal mask for about 20 months with persistent clinical and physiologic improvements. Application of volume ventilation through the nasal CPAP mask is a feasible strategy for providing long-term mechanical ventilation to selected patients with COPD and respiratory failure.
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PMID:Intermittent volume cycled mechanical ventilation via nasal mask in patients with respiratory failure due to COPD. 155 51

Arterial oxyhemoglobin saturation (SaO2) falls to a variable extent during sleep in patients with COPD. These nocturnal falls in SaO2 may contribute to the development of pulmonary hypertension, nocturnal cardiac arrhythmias, and death during sleep. In order to determine which physiologic factors measured during wakefulness might contribute to the development of nocturnal hypoxemia, we performed multiple stepwise linear regression analyses in 48 patients with stable COPD with mean and lowest nocturnal SaO2 as dependent variables. It was concluded that the two chief variables, measured while awake, which are associated with alterations in nocturnal oxygenation in patients with COPD are baseline awake SaO2 and PaCO2. Hypercapnia appears to be a risk factor for the development of nocturnal hypoxemia in patients who are normoxic while awake.
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PMID:Daytime hypercapnia in the development of nocturnal hypoxemia in COPD. 229 55


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