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Query: UMLS:C0001127 (respiratory acidosis)
 1,501 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of the present study was to examine the influence of a respiratory acidosis on the blood lactate (La) threshold and specific blood La concentrations measured during a progressive incremental exercise test. Seven males performed three step-incremental exercise tests (20 W.min-1) breathing the following gas mixtures; 21% O2 balance-nitrogen, and 21% O2, 4% CO2 balance-nitrogen or balance-helium. The log-log transformation of La oxygen consumption (VO2) relationship and a 1 mmol.l-1 increase above resting values were used to determine a La threshold. Also, the VO2 corresponding to a La value of 2 (La2) and 4 (La4) mmol.l-1 was determined. Breathing the hypercapnic gas mixtures significantly increased the resting partial pressure of carbon dioxide (PCO2) from 5.6 kPa (42 mm Hg) to 6.1 kPa (46 mm Hg) and decreased pH from 7.395 to 7.366. During the incremental exercise test, PCO2 increased significantly to 7.2 kPa (54 mm Hg) and 6.8 kPa (51 mm Hg) for the hypercapnic gas mixtures with nitrogen and helium, respectively, and pH decreased to 7.194 and 7.208. In contrast, blood PCO2 decreased to 4.9 kPa (37 mm Hg) at the end of the normocapnic exercise test and pH decreased to 7.291. A blood La threshold determined from a log-log transformation [1.20 (0.28) l.min-1] or as an increase of 1 mmol.l-1 [1.84 (0.46) l.min-1] was unaffected by the acid-base alterations. Similarly, the VO2 corresponding to La2 and La4 was not affected by breathing the hypercapnic gas mixtures [2.12 (0.46) l.min-1 and 2.81 (0.52) l.min-1, respectively].(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of a respiratory acidosis on the exercise blood lactate response. 191 34

The study was aimed at informing about the results of metabolic trials in large cattle stocks for the period from 1977 to 1980, particularly in view of the dynamics of changes in different metabolic parameters in each year season. The histogram method of statistical evaluation was used. Attention is drawn to the prevailing risk factors in each season and it is possible to investigate the general trend of the rise of new metabolic disorders, or suppression of older ones, in large cattle stocks. The risk metabolic factors of each season can be derived from the results. The summer season is characterized by the tendency to metabolic and respiratory acidosis, by the highest elimination of calcium combined with potassium stress, and by a lack of sodium ions. In the autumn the animals show a more pronounced form of metabolic and respiratory acidosis, not always sufficiently compensated; the liver is overloaded, there is a tendency to hypocalcaemia, and ketosis occurs more frequently, often very pronounced. In winter the acid-base balance of blood improved, acidosis is compensated more intensively by the renal route, calcium is increasingly eliminated in the urine, the overload on liver function is at its maximum, and ketosis occurs most frequently. The spring findings included increased elimination of calcium with the urine, the lowest Ca X P product over the whole year (this is in a high correlation with the higher activities of the ALP enzyme). the highest load of nitrogen compounds and worsened haemogenesis. It can be stated that the mentioned results represent some improvement in the metabolic profile as compared with earlier studies. The situation in enzyme activities can be regarded as a factor of deterioration: high activities of alkaline phosphatase documenting a tension in the metabolism of calcium and phosphorus, and increasing occurrence of chronical overloading of liver function, particularly in winter.
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PMID:[Changes in metabolic indicators in cattle by season of the year]. 681 64

The physiological pattern of regional pulmonary blood flow is mainly determined by the relationship of pulmonary arterial, venous, and alveolar pressures. Changes in alveolar pressure and pulmonary geometry may therefore be expected to influence regional perfusion, which is a key determinant of pulmonary gas exchange. Unilateral thoracotomy is usually performed with the patient in the lateral decubitus position. The present study examined the influence of mechanical factors on regional pulmonary blood flow distribution in rabbits in the lateral decubitus position during normoxia and unilateral hypoxia. METHODS. Anaesthetised white New Zealand rabbits (n = 8) weighing 2200-3900 g (mean = 2860 g) received central venous injections of radioactive microspheres while in the left lateral decubitus position during spontaneous breathing (SB) and during mechanical ventilation (two-lung ventilation, 2LV), under closed (2LVC) and open chest (2LVT) conditions, as well as during unilateral hypoxia of the nondependent lung induced by nitrogen inflation (1LVN) or atelectasis (1LVA). The method used for one-lung ventilation (1LV) has been previously described in detail. Arterial, central venous, and pulmonary arterial pressures were recorded continuously. Lungs were excised, dried in the inflated state, and cut into 16 sagittal slices, which were further divided into lobar components, the lower lobes into center and periphery. The radioactivity of each specimen was measured in a gamma-counter; perfusion of the individual tissue specimens was quantified using the software program MIC III. The Friedman test followed by paired comparisons according to Conover was used for statistical analysis of differences between the experimental phases. Perfusion of central and peripheral parts of isogravitational slices was compared by use of the Wilcoxon matched pairs test. Values are given as means +/- SE; the level of significance was P < 0.05 unless otherwise indicated. RESULTS AND DISCUSSION. Haemodynamic parameters did not differ significantly between the experimental phases (Table 1). Compared to 2LV, a significant increase in venous admixture (P < 0.05) and a corresponding decrease in PaO2 (P < 0.01) were observed during 1LV. This effect was significantly more pronounced during 1LVA as compared to 1LVN (P < 0.01). Since inspiratory pressure was kept constant throughout the experiments, moderate respiratory acidosis developed during both phases of 1LV. Regional perfusion (Qr) of the nondependent lung was slightly reduced during 2LVC compared to SB and 2LVT. One-lung ventilation induced a significant decrease in perfusion of the hypoxic lung (P < 0.001 1LVN, 1LVA vs. SB,2LVC,2LVT). In accordance with the data obtained from blood gas analysis and oximetry, this effect was more pronounced during N2 insufflation than during atelectasis (P < 0.01 1LVN vs. 1LVA). Among the factors that may account for this effect, PaCO2 did not differ significantly between both phases of 1LV. During N2 insufflation PO2 at the hypoxia-sensitive site is lower than during atelectasis, where it equals mixed-versus PO2 (PvO2). The difference in local PO2 is unlikely, however, to have caused the changes in regional perfusion between 1LVN and 1LVA, since PvO2 was as low as 40 mmHg during 1LVA and the pulmonary vascular response to hypoxia has been found to reach its maximum in this PO2 range [2, 11]. Enhanced redistribution of regional perfusion during 1LVN as compared to 1LVA is therefore most likely attributed to differences in alveolar pressure and pulmonary geometry. Apart from a radial perfusion gradient in the right lower lobe during 2LVC and 2LVT, no isogravitational Qr gradients were observed. CONCLUSION. We conclude that controlled mechanical ventilation in the lateral decubitus position causes only minor changes in vertical blood flow distribution.
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PMID:[The effect of mechanical ventilation, thoracotomy, and one-lung respiration on intrapulmonary perfusion distribution. An animal experimental study]. 761 78

Carbon dioxide is the most commonly used gas for abdominal insufflation in laparoscopy today. Due to the solubility of carbon dioxide large volumes are absorbed into the circulation causing a high PCO2 and a low pH (respiratory acidosis). Carbon dioxide is also stored in several sites in the body and is released at the conclusion of the procedure prolonging the respiratory acidosis when the patient is least able to cope with this additional burden. Cardiac effects of CO2 consist of a lowering of the arrhythmia threshold, increased blood pressure, pulse and cardiac output. At a sustained high level this can lead to cardiac depression and death. These effects are particularly prone to occur in cardiac and respiratory cripples. Other gases that have been used include air, oxygen, nitrous oxide and nitrogen. Their use has been discontinued because of the danger of embolism. Air, oxygen and nitrous oxide are also not safe to use in the presence of electrosurgical instruments thereby limiting their usefulness even further. Helium has been proposed as a very promising alternative to CO2. In the laboratory and in a clinical trial, helium has not produced the respiratory acidosis associated with CO2 insufflation. This is further evidence that the acidosis is not primarily due to elevation of the diaphragm and consequent increased dead space, but to the large amount of CO2 that is absorbed directly from the peritoneal cavity. Helium would seem to be the gas of choice at this time as it comes close to fitting the criteria for an ideal insufflating gas. Helium is clear and colorless, allowing unimpeded vision to the operator. It is non toxic, not flammable or explosive and can be safely used with electrocautery and laser. Helium is easy to handle and not very soluble which decreases the amount absorbed from the peritoneal cavity and consequently the amount used. That which is absorbed is quickly cleared by the lungs. Helium is metabolically inactive (in contrast to CO2) and does not interfere with normal metabolic processes. In view of this promising initial work, further studies are indicated.
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PMID:Helium insufflation in laparoscopic surgery. 884 34

Nutritional and management strategies for dairy cattle are designed to prepare the cow for lactation and to minimize the incidence of metabolic diseases around calving. However, strategies initiated during the dry period should also consider the potential effects on the calf prior to and after calving. Fetal requirements for energy and protein are significant, particularly during the last trimester of gestation. Energy requirements increase to 1.3 to 1.5 times maintenance in late pregnancy; therefore, the formulation of rations for dry cows must contain sufficient energy to support fetal growth plus maintenance. Protein requirements during pregnancy increase, particularly during the last 2 mo. Colostrum is a source of immune components and nutrients to the neonate and contains more protein, immunoglobulins (Ig), nonprotein nitrogen, fat, ash, vitamins, and minerals than does milk. Because some vitamins do not cross the placental barrier, colostrum is the primary source of these nutrients for the calf after birth. Colostrum from cows that are not supplemented with vitamin E during the dry period may provide inadequate vitamin E to calves after birth. The Ig concentration in colostrum is not markedly affected by prepartum protein nutrition; diets containing high crude protein (CP) generally increase the nonprotein fraction of colostrum, but low CP diets do not affect the CP or Ig concentration of colostrum. However, data from beef calves suggest that absorption of IgG may be impaired when low protein diets are fed during the dry period. Diets for dry cows may be balanced to reduce the cation to anion ratio, which may reduce the incidence of parturient paresis. Recent research also suggests that these diets might increase the incidence of calves born in respiratory acidosis, which may impair the acquisition of passive immunity.
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PMID:Nutrient and immunity transfer from cow to calf pre- and postcalving. 981 84

Carfentanil citrate was given orally to five adult brown bears (Ursus arctos) on 14 separate occasions during the winter and summer to determine effective anesthetic dosages and how season may alter these dosages. Lower blood urea nitrogen:creatinine ratios, depressed appetite, and decreased activity levels in the winter versus summer were reflective of different metabolic states, even though bears were not hibernating in the winter. Doses of carfentanil citrate between 6.0 and 15.2 microg/kg were mixed with 5-10 ml of honey, which the bears licked voluntarily from a spoon. During each anesthetization, respiratory and heart rates, hemoglobin saturation, temperature, electrocardiogram, blood gas values, and level of consciousness were monitored and utilized to determine effective dosages. Mean (+/- SE) dose requirements in the winter were 7.6 +/- 0.4 microg/kg, whereas a greater mean dose of 12.7 +/- 0.5 microg/kg was required in the summer (P < 0.05). After ingestion began, sternal recumbency occurred in an average of 7.5 min (range: 4-11 min), and full restraint and safe handling was achieved in 21 min (range: 8-40 min). At the end of each procedure, naltrexone was given as the reversal agent at a ratio of 100 mg naltrexone per 1 mg carfentanil, with 25% of the dose given i.v. or i.m. and 75% given s.c. Mean reversal time was 6 min after injection of naltrexone (range: 4-9 min). Rapid induction and recovery times and ease of oral administration make carfentanil citrate an effective anesthetic agent for use in brown bears. However, hypoventilation and respiratory acidosis were noted in all bears, and oxygen insufflation is recommended.
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PMID:Carfentanil citrate used as an oral anesthetic agent for brown bears (Ursus arctos). 1279 Apr 24

OBJECTIVE: To describe improved ventilation during high-frequency oscillatory ventilation when a nitrogen-oxygen gas mixture is replaced by a helium-oxygen gas mixture. DESIGN: Case series. SETTING: A tertiary pediatric intensive care unit. PATIENTS: Five patients with hypoxemic respiratory failure who developed persistent respiratory acidosis during treatment with high-frequency oscillatory ventilation. INTERVENTIONS: Introduction of helium-oxygen into a conventional high-frequency oscillatory ventilation circuit. MEASUREMENTS AND MAIN RESULTS: Blood gas values (pH, Pco2, and Po2) were compared in these patients during treatment with high-frequency oscillatory ventilation with nitrogen-oxygen gas flow and then for several hours after a change in treatment to helium-oxygen gas flow. An initial 24% decrease in Pco2 was documented, and an ultimate 43% decrease in Pco2 was observed. The mechanism for this improved ventilation may be related to improved gas flow properties as well as increased CO2 diffusion resulting from helium's low-mass density. Oxygenation was not adversely affected in any way. CONCLUSION: In patients with hypoxemic respiratory failure and in whom respiratory acidosis develops during high-frequency oscillatory ventilation, the use of helium-oxygen rather than nitrogen-oxygen may improve ventilation and decrease ventilator-related trauma. Further investigation is needed to validate these findings and to elucidate the mechanisms of improved ventilation.
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PMID:Heliox improves ventilation during high-frequency oscillatory ventilation in pediatric patients. 1281 83

Deliberate induction of prophylactic hypercapnic acidosis protects against lung injury after in vivo ischemia-reperfusion and ventilation-induced lung injury. However, the efficacy of hypercapnic acidosis in sepsis, the commonest cause of clinical acute respiratory distress syndrome, is not known. We investigated whether hypercapnic acidosis--induced by adding CO2 to inspired gas--would be protective against endotoxin-induced lung injury in an in vivo rat model. Prophylactic institution of hypercapnic acidosis (i.e., induction before endotoxin instillation) attenuated the decrement in arterial oxygenation, improved lung compliance, and attenuated alveolar neutrophil infiltration compared with control conditions. Therapeutic institution of hypercapnic acidosis, that is, induction after endotoxin instillation, attenuated the decrement in oxygenation, improved lung compliance, and reduced alveolar neutrophil infiltration and histologic indices of lung injury. Therapeutic hypercapnic acidosis attenuated the endotoxin-induced increase in the higher oxides of nitrogen and nitrosothiols in the lung tissue and epithelial lining fluid. Lung epithelial lining fluid nitrotyrosine concentrations were increased with hypercapnic acidosis. We conclude that hypercapnic acidosis attenuates acute endotoxin-induced lung injury, and is efficacious both prophylactically and therapeutically. The beneficial actions of hypercapnic acidosis were not mediated by inhibition of peroxynitrite-induced nitration within proteins.
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PMID:Hypercapnic acidosis attenuates endotoxin-induced acute lung injury. 1469 4

Pronounced alterations occur in the biochemical findings in acute poliomyelitis. These are derived from three major mechanisms: (a) inefficient pulmonary gaseous exchange, resulting in respiratory acidosis; (b) profound changes in nitrogen metabolism, resulting in decreased serum albumin, tissue destruction, and increased urinary nitrogen; (c) losses of electrolytes through extrarenal channels such as lung and tracheal secretions, sweating, and gastrointestinal disturbances. The extent of these alterations may be defined by appropriate serum and urinary biochemical determinations. These determinations are valuable both from a therapeutic and a prognostic standpoint. They also contribute to further understanding of physiologic and pathologic conditions in acute poliomyelitis.
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PMID:Biochemical alterations in acute human poliomyelitis electrolyte patterns and trends. 1477 9

"Cold-stunning" of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This study investigated initial and convalescent venous blood gas, acid-base, and critical plasma biochemical data for 26 naturally cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) from Cape Cod, MA, USA. Samples were analyzed for pH, pCO(2), pO(2), bicarbonate, plasma osmolality, sodium, potassium, chloride, ionized calcium, ionized magnesium, glucose, lactate, and blood urea nitrogen using a clinical point-of-care analyzer. Data were corrected for the patient's body temperature using both species-specific and more general correction methods. In general, venous blood gas, acid-base, and plasma biochemical data obtained for surviving cold-stunned Kemp's ridley sea turtles were consistent with previously documented data for sea turtles exposed to a wide range of temperatures and physiologic stressors. Data indicated that turtles were initially affected by metabolic and respiratory acidosis. Initial pH-corrected ionized calcium concentrations were lower than convalescent concentrations, and initial pH-corrected ionized magnesium concentrations were higher than convalescent concentrations.
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PMID:Metabolic and respiratory status of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii). 1743 40


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