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

To examine the adaptations to low O2 and high CO2 among fossorial and nonfossorial rodents, hematological parameters were determined for laboratory rats, the valley pocket gopher (Thomomys bottae) from 250 m, and the mountain pocket gopher (T. umbrinus melanotis) from 3150 m. Hematocrit, hemoglobin concentration, and O2 capacity were higher in pocket gophers than in rats. Blood PO2 at 50% saturation and pH 7.4 was 33 mmHg for both gophers and 39 mmHg for rats. Bohr factors for all three rodents were similar (-0.55 to -0.61) but buffer value, delta log PCO2/delta pH, was -2.54 for T. umbrinus, -1.97 for T. bottae, and -0.98 for Rattus. Concentrations of total acid-soluble phosphates were 50-75% higher in gophers than in rats, while bicarbonate values were within the normal mammalian range. All three rodents had similar myoglobin concentrations in cardiac muscle. Myoglobin concentrations were significantly higher in skeletal muscles (diaphragm, gastrocnemius) of T. umbrinus when compared to T. bottae, and significantly higher in both gophers when compared to rats. These differences may constitute important adaptations to the hypoxia and hypercapnia in burrows; certain of these factors in pocket gophers respond to the additional stress of high altitude hypoxia.
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PMID:Respiratory adaptations in burrowing pocket gophers from sea level and high altitude. 0 20

The oxygen affinity of hemoglobin and the factors determining the position of the oxygen dissociation curve were investigated in twenty-five patients with severe chronic obstructive lung disease. Patients have been separated into three groups: group I showed a normal or mild decrease of PaO2, group II a moderate fall in arterial oxygen pressure, and group III a severe hypoxia with balanced acid-base equilibrium and hypercapnia. Blood hemoglobin exhibited a significant increase in all groups, indicating an improved oxygen transport. In most patients a leftward shifting of the oxygen dissociation curve occurred. It is discussed that the tendency to left shifting is based upon alkalosis inside the red cells, evidently demonstrated in all groups studied. 2,3-diphosphoglycerate showed no close relation to evaluated oxygen affinity of hemoglobin. The evidence for an increased oxygen affinity may reveal a further compensatory mechanism in oxygen transport in patients with pulmonary disorders. Additionally the alkalosis inside the cells may counterbalance too great a right shifting of oxygen dissociation curve in vivo when severe hypoxia and hypercapnia occur.
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PMID:Oxygen affinity of haemoglobin and red cell acid-base status in patients with severe chronic obstructive lung disease. 1 84

The effects on hemoglobin oxygen transport of acute respiratory acidosis have been studied in dogs inhaling a gaseous mixture with 12% CO2 (O2 21%) for two to five hours. In a first series of experiments, it was shown that the shape of the oxyhemoglobin dissociation curve (ODC) was not modified by severe acidosis (pH congruent to 7) lasting for two and a half hours. The Hill number (N equals 2.6) did not change significantly. The aim of the second experimental series was to stuey the Bohr effect and the hemoglobin oxygen affinity (P50). The control value for the respiratory Bohr coefficient (B) was --0.54; neither after two hours (--0.52), nor after five hours of hypercapnia (--0.55) was it significantly modified. The P50 expressed at arterial pH was much increased in acidosis (congruent to 45 torr); when expressed at standard p/ 7.4, it was slightly but significantly decreased (congruent to 1 torr) at the fifth hour. At the same time there was a decrease (p smaller than 0.05) in the erythrocyte 2,3-DPG approaching 15 p. cent; on the other hand the ATP concentration did not change significantly. No significant individual correlation was found between P50(7.4), 2,3-DPG and mean hemoglobin corpuscular concentration. These results suggest that during severe respiratory acidosis neither a change in the shape of ODC, nor a change in Bohr effect do affect the hemoglobin oxygen transport. The main characteristic remains the decrease in oxygen affinity of hemoglobin, due to the erythrocyte [H+] increase induced by hypercapnia ; this phenomenon is observed as long as the 2,3-DPG decrease stays moderate.
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PMID:[Hemoglobin oxygen transport during experimental acute hypercapnia (author's transl)]. 23 80

Rats were exposed 24 hours a day to carbon dioxide, 8 +/- 1%, during 2 and 4 weeks under normoxic conditions (21% oxygen). On the last day, blood was taken from the abdominal aorta under anesthesia. Leukocyte and erythrocyte counts, hemoglobin concentration, and mean cell volume were electronically measured. Hematocit and Wintrobe indexes were calculated. Leukocyte differential counts and peroxidase activity were determined on blood smears. After 4 weeks of hypercapnia, a slight decrease of neutrophilic granulocytes was observed. In mature polymorphs, peroxidase activity (cytochemically demonstrated) simultaneously decreased. Erythrocyte counts and mean cell volume remained unchanged. The most important hematological disturbance was an hemoglobin concentration drop. Consequently, it was concluded that an hypochromic anemia characterized the permanent normoxic hypercapnia in rats.
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PMID:Blood effects of permanent normoxic hypercapnia in conventional rats. 28 61

Massive pulmonary hemorrhage is a complication which frequently leads to death in newborns with conditions susceptible to surgical treatment. Out of 112 postmortem studies, focal hemorrhage was found in 38 (33.9%) and massive in 34 cases (30.3%). In this series, congenital anomalies were found in digestive tract in 70.5% of the patients. Prematurity andlow weight were not important factors as was hypoxia, which was evident in 70.5% of the cases. Manifestations of respiratory insufficiency, shock, rales in lung fields, bleeding in other places different from the lung, blood leaking through upper respiratory ducts, are all clinical features of diagnostic aid. Disturbances in coagulation tests were detected, the same as drop in figures of hemoglobin, acidosis, hypoxia and hypercapnia. Gram-negative germs, with a predominance of Klebsiella, were isolated in 33 cultures. The radiographic finding with reticulogranular image was unfrequent. Among other precipitating factors of pulmonary hemorrhage, identification was made of the surgical disease by itself, surgical and anesthetic procedures, of ventilatory assistance and therapy with oxygen at high concentration for long periods of time.
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PMID:[Massive pulmonary hemorrhage in surgical pathology of the newborn infant]. 87 35

2,3-DPG and P50 were measured in 23 patients with chronic obstructive lung disease. All patients had a chronic hypercapnia (PaCO2 greater than or equal to 45 Torr). They are shared in 3 groups, according to hemoglobin content [Hb] and hypoxia : group I(PaO2 = 48.0 +/- 2.4 Torr ; [Hb] = 15.9 +/- 0.3 g. 100 ml-1; n = 9), (M +/- 1 SE); group II (PaO2 = 46.4 +/- 5.0 Torr; [Hb] = 11.6 +/- 0.7 g. 100 m[-1; n = 7); group III(PaO2 = 61.4 +/- 2.4 Torr; [Hb] = 13.3 +/- 0.4 g. 100 ml-1; n = 7). 2,3-DPG (group I : 1.05 +/- 0.06 mole.moleHb-1; group II : 1.02 +/- 0.08; group III : 1.11 +/- 0.08) was not significantly different of 2,3-DPG value of 12 control subjects (0.96 +/- 0.04). P50 of group I (26.9 +/- 0.9 Torr) and group III patients (28.1 +/- 1.6 Torr) was not significantly different of control value of P50 (27.4 +/- 0.5 Torr). P50 of group II patients (29.6 +/- 0.8 Torr) was significantly higher than P50 control and group I values (p less than 0.05). All the patients of group II died. These results suggest that in patients with chronic obstructive lung disease : 1) P50 value is different with various clinical conditions; 2) P50 increase is a compensatory mechanism in severe hypoxemia with anemia, but is not sufficient; 3) [Hb] is the best data for clinical prognosis.
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PMID:[Study of P50 and 2,3-diphosphoglycerate in 23 bronchoemphysema patients as a function of hypoxia and hemoglobin concentration]. 89 17

Quantitation of actual and expected complete compensation for chronic hypercapnia in man is facilitated by addition of data of Brackett et al. in the form of an arc to the Siggaard-Andersen alignment nomogram. Percentage of compensation is defined as 100 times the ratio of observed to predicted (fully compensated) base excess at the patient's PCO2. Extracellular fluid base excess, defined as BE3, is estimated from a 3-g hemoglobin line added to the nomogram.
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PMID:Acid-base balance nomogram--a Boston-Copenhagen detente. 97 8

The cardiovascular effects of equipotent (minimum alveolar concentration; MAC) doses of halothane versus halothane plus 25% N2O (H25N2O) in spontaneously breathing dogs do not differe except that nitrous oxide increased mean arterial pressure (AP) and decreased arterial oxygen partial pressure (PAO2). When 75% nitrous oxide was added to halothane anesthesia, AP, mean pulmonary artery pressure (PAP), heart rate (HR), cardiac output (CO), stroke volume (SV), total peripheral resistance (TPR), and left ventricular work (LVW) increased and PAO2 and hemoglobin saturation decreased. Arterial oxygen tensions below 80 torr were common at moderate and deep anesthetic levels of halothane plus 75% N2O (H75N2O). The specific contribution of N2O, hypoxemia, hypercapnia, or temporal recovery (or a combination of these) in producing cardiovascular stimulation were not determined.
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PMID:Circulatory effects of halothane and halothane-nitrous oxide anesthesia in the dog: spontaneous ventilation. 111 85

The first case of "idiopathic" persistence of the fetal cardiopulmonary circulatory pathway with survival after a prolonged course is documented by serial cardiac catheterizations. All previously reported infants have either markedly improved within the first week of life or subsequently died. This entity has been described in term infants with prenatal or perinatal distress who present with tachypnea and cyanosis from birth. The chest radiograph is remarkable for the absence of pulmonary parenchymal pathology and the hemoglobin and hematocrit are normal. Blood gas determinations indicate hypoxia and acidosis with or without hypercarbia. Cardiac catheterization and angiography reveal an anatomically normal heart with severe pulmonary hypertension, left ventricular pressure lower than right ventricular pressure, and right-to-left venoarterial shunting through the fetal channels (atrial and or ductal levels). It is postulated that this entity may result from antenatal factors that affect the pulmonary vasculature and its subsequent adjustment to extrauterine life. These factors may include abnormal intrauterine stress resulting in excessive hypertrophy of the pulmonary arteriolar smooth muscle, or abnormal pulmonary vascular responsiveness to the usual vasoactive stimuli before or after birth, or an immature or dysfunctioning enzyme system necessary for the normal decrease in pulmonary artery pressure.
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PMID:Persistence of the fetal cardiopulmonary circulatory pathway: survival of an infant after a prolonged course;. 116 63

Six black infants and young children with high titers of milk precipitins were identified by screening the sera of 160 children with idiopathic chronic lung disease. None of the six had immunoglobulin deficiency, elevation of sweat chlorides, SS hemoglobin, or recurrent aspiration. All six children had typical manifestations of milk-induced pulmonary hemosiderosis: recurrent pulmonary infiltrates (6/6), hemosiderin-laden pulmonary macrophages (5/6), intermittent wheezing (5/6), eosinophilia (4/6), anemia (4/6), iron deficiency (4/4), failure to thrive (4/6), and elevated levels of serum IgE (4/4). Three children also had chronic rhinitis and eventually developed large adenoids, hypercapnia and acidosis during sleep, and right heart failure. Elimination of cow milk from the diet, symptomatic therapy, and adenoidectomy when indicated resulted in improvement of all six patients. Pulmonary hemosiderosis and some cases of upper airway obstruction with pulmonary hypertension appear to be two stages, early and delayed, of the same immunophysiologic process. Early dietary intervention may prevent the cardiovascular complications of this process.
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PMID:Hyperreactivity to cow milk in young children with pulmonary hemosiderosis and cor pulmonale secondary to nasopharyngeal obstruction. 117 19


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