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At least 19 recordsLinked to original sources
PubMed1975

The distribution and movements of carbon dioxide, carbonic acid and bicarbonate between blood and milk in the goat.

1. A-V differences and milk concentrations of respiratory gases, pH, HCO3 and H2CO3 have been measured in lactating goats and cows. 2. The pH and [HCO3 minus] of milk were significantly lower than those of plasma while milk PCO2 was virtually identical to that of mammary venous blood. [H2CO3+ dissolved CO2] was similar in milk and blood. 3. 14-C (from injected [14-C]HCO3 minus was found to cross the mammary epithelium in both directions. 14-C also passed across the duct epithelium and since this epithelium has previously been shown to be impermeable to ions it is argued that 14-C crossed in an unionized form, i.e. as CO2 and/or H2CO3. 4. Hourly milking with the aid of oxytocin raised milk pH, [HCO3 minus], [H2CO3], [Na] and E1Cl], and lowered [K], [lactose] and [phosphate]. These effects are discussed in relation to the hypothesis proposed previously for the action of oxytocin on milk composition. 5. A scheme for the distribution and movements of CO2, H2CO3 and HCO3 minus between extracellular fluid and milk is suggested, and discussed in relation to Cl minus transport.

Animals↗
PubMed1977

Measurement of carbon dioxide output, alveolar carbon dioxide concentration and alveolar ventilation in the neonate.

A system is described for measuring carbon dioxide output and alveolar carbon dioxide concentration in the neonate and for deriving the volume of alveolar ventilation. Air is drawn through a soft rubber face mask applied loosely to the face so that all expired gas is entrained. A fraction of the flow is sampled by an infra-red analyser, the signal from which is integrated to provide a measure of carbon dioxide output. Alveolar carbon dioxide concentration is measured by continuous sampling of expired gas through a nasal catheter. The response time of the catheter-analyser system is 140 ms. In 20 healthy 1-day-old neonates the mean carbon dioxide excretion was 5.86 ml/min. kg-1 (STPD) and the mean alveolar PCO2 was 4.85 kPa. From these measurements mean alveolar ventilation 147 ml/min. kg-1 (BTPS) was calculated. These results are similar to those obtained by other methods.

Carbon Dioxide↗
PubMed1978

Quality control of measurements of pH, carbon dioxide tension, and total carbon dioxide in plasma.

We have measured total carbon dioxide in plasma with a new carbon dioxide analyzer, and compared the results with total carbon dioxide data derived from measurements of carbon dioxide tension and pH. The results agree sufficiently well to demonstrate that the new instrument provides a simple, efficient procedure for monitoring the precision and accuracy of pH, carbon dioxide tension, or total carbon dioxide in plasma.

Blood↗
PubMedDate not supplied

Intravenous procaine as a supplement to general anesthesia for carbon dioxide laser resection for carbon dioxide laser resection of laryngeal papillomas in children.

Procaine suppresses the cough reflex, decreases laryngeal irritability, and has general anesthetic properties. For these reasons, 14 pediatric patients undergoing CO2 laser resection of laryngeal papillomas were studied in which an intravenous infusion of procaine (1 mg/kg/min) was added to N2O-O2 halothane/enflurane general anesthesia immediately following endotracheal intubation. These patients were compared to nine patients receiving the same anesthesia without procaine. The mean age of both groups was 11 years. There was no difference between the groups in duration of anesthesia or surgery. Emergence, however, averaged 15 minutes in study patients compared to 36 minutes in the control group (p less than 0.01). There was no difference in anesthetic concentrations required to maintain satisfactory operative conditions in the two groups. Muscle relaxants were required intraoperatively in seven control patients but in none of the study patients. The surgeon ranked the operative conditions excellent in all study patients but poor in seven of the nine control patients. Five of the latter required postoperative treatment of laryngeal complications, including reintubation in three. Only one of the study patients had postoperative stridor. No evidence of procaine toxicity was noted in the study patients with total doses ranging from 500--3600 mg. Intravenous procaine is useful in pediatric patients having endoscopic laryngeal operations.

Anesthesia, Inhalation↗
PubMed1975

The effect of acetazolamide on myocardial carbon dioxide space.

Carbon dioxide, water and vascular space were measured in the heart muscle of the dog before and after the administration of acetazolamide. In contrast to the skeletal muscle whose CO2 space was markedly reduced by acetazolamide, cardiac muscle CO2 space was only minimally reduced. This suggests that cardiac muscle does not have extravascular carbonic anhydrase. Its presence in skeletal muscle and absence in cardiac muscle probably relates to the differences in cell size between the two types of muscle and their differing degree of vascularity.

Acetazolamide↗
PubMed1978

The respiratory response to inhaled carbon dioxide in man after 3 hours exposure to 3% carbon dioxide.

1. The respiratory response to inhaled 3% and 6% CO2 was measured in 10 normal subjects after a 3 h acclimatization period to 3% CO2 in an environmental chamber. Control studies were carried out after a 3 h period of breathing air in the chamber. 2. At the end of the acclimatization period studies were carried out during 20 min periods breathing 3% CO2, 6% CO2 and air. 3. At 2-min intervals during the studies measurements were made of tidal volume (Vt), breathing frequency (fR), minute ventilation (Ve), viscous pulmonary rate of work (Wp) and total viscous rate of work across the lungs and apparatus (Wt). Blood gas tensions were measured at the end of this period. 4. After acclimatization to 3% CO2 there was a significant shift in the response curves Ve/Pa,CO2 and Wt/Pa,CO2 such that subjects showed higher Pa,CO2 values for given values of Ve or Wt. There was no significant change in the slope of the response curves. 5. No correlation was found between the slope of the response curve after the control period breathing air and the degree of shift of the response curve. 6. There was no difference in respiratory pattern or in pulmonary resistance. 7. Similar results were found in two subjects studied after 24 h acclimatization to 3% CO2 but one subject also showed a significant change in the slope of the Ve/Pa,CO2 curve.

Acclimatization↗
PubMed1978

Scintigraphic detection of pulmonary emboli by serial positron imaging of inhaled 15O-labeled carbon dioxide.

Inhaled radioactive carbon dioxide is retained in pulmonary blood distal to embolic obstruction and appears as an area of increased radioactivity that delineates the site and magnitude of the affected zone. The scintigraphic detection of pulmonary emboli by serial imaging of inhaled carbon dioxide labeled with cyclotron-produced 15O2 was evaluated in 27 patients undergoing conventional pulmonary ventilation/perfusion imaging and pulmonary arteriography. Fifteen patients proved to have pulmonary emboli on arteriography. Sensitivity (87%) and specificity (92%) rates for inhalation imaging were superior to those of conventional ventilation/perfusion imaging (P less than 0.05). Clearance of 15O2 activity was markedly delayed over embolized pulmonary segments (mean half time of 47.0 +/- 11.1 seconds [S.E.M.]) in comparison to normal segments (mean of 3.6 +/- 0.08 seconds; P less than 0.001). Pulmonary imaging by this method provides an approach to the detection of pulmonary emboli that is relatively sensitive and specific and permits analysis of persisting perfusion in embolized pulmonary segments. A major practical limitation, however, is the necessity of a nearby cyclotron.

Adult↗
PubMed1975

Ventilatory response of healthy Nigerians and Europeans to carbon dioxide.

Ventilatory response to carbon dioxide was measured by the rebreathing technique in 32 Nigerians and 20 Europeans resident in Lagos. Although the Europeans had larger physical characteristics and lung volumes than Nigerians, the responses to carbon dioxide were similar. The range of ventilatory response was 0,55 to 4,2 and 0,7 to 3,7 1/min/mm Hg for Nigerians and Europeans respectively. These results show that Nigerians are as sensitive to carbon dioxide as their European counterparts.

Adult↗
PubMed1979

Microsurgical conization of the cervix by carbon dioxide laser.

The carbon dioxide (CO2) laser has been used to treat cervical intraepithelial neoplasis (CIN) by vaporization of colposcopically visible lesions. Recently, several investigators have reported a series of laser-treated CIN with very promising cure rates. The use of the laser to excise cervical tissue surgically has been neglected. A series of patients who have undergone cervical cone biopsies taken by the CO2 laser is presented. The tissue sections obtained from these cone biopsies are suitable for pathologic interpretation and study. The complication rate for cervical conization by laser is very low. Other advantages of this method of cervical conization are discussed.

Biopsy↗
PubMed1977

Excision of buccal hemangioma by carbon dioxide laser beam.

The carbon dioxide laser beam was used successfully to extirpate a large buccal hemangioma in a child. No hemostats were required, as this new surgical modality affords a practically bloodless operative field. Tissue necrosis occurs only minimally at the borders of the incision. Operative intervention with the carbon dioxide laser beam in cases of hemangioma and other tumors of the oral cavity is advocated.

Carbon Dioxide↗
PubMed1975

The assessment of acid-base disturbance in man by the use of carbon dioxide titration curves.

1. Carbon dioxide titration curves were determined in vivo in dog and man at various degrees of acute non-respiratory acidaemia and alkalaemia. 2. The slope of the CO2 titration curve (delta log Pco2/delta pH) was found to increase with the severity of the acute non-respiratory alkalaemia the slope (delta log Pco2/delta pH) tended towards unity. 3. A simple scheme based on the CO2 titration curves determined in vivo has been proposed for the assessment of acute acid-base disturbances in man. 4. Carbon dioxide titration curves were also determined in vivo in patients with chronic respiratory and non-respiratory acidaemia and it was found that these curves were not significantly different from those obtained in states of acute acid-base disturbances. It is therefore suggested that the scheme described in this paper is applicable to all acid-base disturbances.

Acid-Base Equilibrium↗
PubMed1975

A paramagnetic method for measuring the carbon dioxide concentration of a gas.

A paramagnetic method of carbon dioxide analysis enables the simultaneous analysis of carbon dioxide and oxygen to be made at 2-min intervals. The method depends upon observing the change of oxygen concentration in a gas mixture before and after absorbing the carbon dioxide component. The carrier-gas in the experiments reported was nitrogen. The output of the paramagnetic meter was measured both by a digital voltmeter and by a chart recorded and the carbon dioxide concentrations calculated from these observations (Y1% and Y2% respectively) were compared with those obtained by Lloyd-Haldane (x%) gas analysis, for carbon dioxide concentration of 2-20% in a range of oxygen concentrations of about 9-90%. The agreement between paramagnetic and Lloyd-Haldane carbon dioxide analysis is shown in the following linear regression equations: Y1=0.996x-0.001 (r=0.9999+/-0.04 SEM of estimate; P less than 0.001); Y2=0.997x-0.006 (r=0.9999+/-0.06 SEM of estimate; P less than 0.001). Carbon dioxide in nitrogen was measured by the prior addition of an arbitrary concentration of oxygen, to a gas sample. The method is applicable to the measurement of carbon dioxide and oxygen, when the carrier-gas may have characteristics which preclude the use of katharometer, infra-red or Haldane analysis.

Absorption↗