Scientific Accuracy Matters

2021 ◽  
Vol 135 (4) ◽  
pp. 724-727
Author(s):  
C. Philip Larson
Keyword(s):  
Partition Coefficients ◽  
Bovine Liver ◽  
Human Muscle ◽  
Human Hemoglobin ◽  
Blood Gas ◽  
Whole Brain ◽  
A Value ◽  
Tissue Homogenates ◽  
Scientific Accuracy ◽  
Tissue Contents

The Solubility of Halothane in Blood and Tissue Homogenates. By Larson CP, Eger EI, Severinghaus JW. Anesthesiology 1962; 23:349–55. Measured samples of human and bovine blood, human hemoglobin, and tissue homogenates from human fat and both human and bovine liver, kidney, muscle, whole brain, and separated gray and white cortex were added to stoppered 2,000-ml Erlenmeyer flasks. To each flask, 0.1 ml of liquid halothane was added under negative pressure using a calibrated micropipette. After the flask was agitated for 2 to 4 h to achieve equilibrium between the gas and blood or tissue contents, a calibrated infrared halothane analyzer was used to measure the concentration of halothane vapor. Calculated partition coefficients ranged from 0.7 for water to 2.3 for blood and from 3.5 for human or bovine kidney to 6 for human whole brain or liver and 8 for human muscle. Human peritoneal fat had a value of 138. The human blood–gas partition coefficient of 2.3 as determined by this equilibration method was well below the previously published value of 3.6.

Determination of plasma bicarbonate of neonates in intensive care.

1988 ◽  
Vol 34 (7) ◽  
pp. 1483-1485 ◽  
Author(s):  
P Masters ◽  
M E Blackburn ◽  
M J Henderson ◽  
J F Barrett ◽  
P R Dear
Keyword(s):  
Intensive Care ◽  
Clinical Significance ◽  
Systematic Bias ◽  
Blood Gas ◽  
Laboratory Measurements ◽  
Blood Samples ◽  
Plasma Bicarbonate ◽  
A Value ◽  
Hasselbalch Equation

Abstract Most modern blood-gas analyzers are programmed to use the Henderson-Hasselbalch equation to calculate a value for plasma bicarbonate. It has been suggested, however, that among acutely ill patients, including newborns, these calculated values may be at variance with measured total CO2. To assess the clinical significance of such errors, we compared calculated bicarbonate with measured total CO2 in 79 blood samples from 40 babies in intensive care. The calculated bicarbonate values consistently exceeded the measured values by about 1.5 mmol/L. Of the errors, 94% were within the range -10% to +20%. When the systematic bias was removed, calculated and measured bicarbonate values agreed within +/- 3.30 mmol/L in 95% of cases. Because calculated values can be obtained much more quickly and frequently than laboratory measurements, we believe that these limits are clinically acceptable.

Characterization of μ, κ, and δ Opioid Binding in Amphibian Whole Brain Tissue Homogenates

2002 ◽  
Vol 301 (1) ◽  
pp. 364-370 ◽  
Author(s):  
Leslie C. Newman ◽  
Steven S. Sands ◽  
David R. Wallace ◽  
Craig W. Stevens
Keyword(s):  
Brain Tissue ◽  
Whole Brain ◽  
Opioid Binding ◽  
Tissue Homogenates

scholarly journals Blood/gas partition coefficients of halothane, isoflurane and sevoflurane in horse blood

2003 ◽  
Vol 91 (2) ◽  
pp. 276-278 ◽  
Author(s):  
A. Bergadano ◽  
R. Lauber ◽  
A. Zbinden ◽  
U. Schatzmann ◽  
Y. Moens
Keyword(s):  
Partition Coefficients ◽  
Blood Gas ◽  
Horse Blood

Right-to-left shunt in normal man determined by the use of tritium and krypton 85

1962 ◽  
Vol 17 (5) ◽  
pp. 778-782 ◽  
Author(s):  
K. Mellemgaard ◽  
N. A. Lassen ◽  
J. Georg
Keyword(s):  
Cardiac Output ◽  
Partition Coefficients ◽  
Normal Subjects ◽  
Back Pressure ◽  
Blue Dye ◽  
Blood Gas ◽  
Quiet Breathing ◽  
Voluntary Hyperventilation ◽  
Arterial Blood ◽  
Normal Man

An aqueous solution of tritium and krypton 85 together with Evans blue dye was injected intravenously in twelve normal subjects during quiet breathing, during apnea, and during voluntary hyperventilation. Arterial blood was sampled within the first 30 sec after the injection to measure the recovery of the two gases. Blood-gas partition coefficients of the two gases at 37 C were determined experimentally and the ratio between them was found to be 3.8 in normal blood. Knowing this ratio it is possible to calculate the fraction of the arterial recovery due to a right-to-left shunt, and that due to alveolar back pressure. The shunt calculated from findings during quiet breathing is 0.26% of the cardiac output. Recoveries during apnea lead to a calculated shunt of identical size, whereas the shunt calculated from the experiments during hyperventilation amounts to only 0.11% of the cardiac output. Submitted on March 8, 1962

Evaluation of the Harleco Micro CO2 system for measurement of total CO2 in serum or plasma.

1978 ◽  
Vol 24 (1) ◽  
pp. 143-145 ◽  
Author(s):  
C W Lam ◽  
I K Tan
Keyword(s):  
Small Volume ◽  
Correlation Coefficients ◽  
Blood Gas ◽  
Gas Analyzer ◽  
Inexpensive Method ◽  
Co2 Gas ◽  
System A ◽  
A Value ◽  
High Concentrations ◽  
Blood Gas Analyzer

Abstract In the Harleco Micro CO2 System a volumetric procedure is used to measure total CO2 content in a small volume (0.10 ml) of serum or plasma. CO2 gas is released by mixing specimen and acid, either manually or with a "Micro CO2 Shaker." Within-batch CV's by manual and machine shakings were, respectively, 7.7 and 5.6% for a total CO2 value of 8 mmol/liter, decreasing to 2.0 and 1.4% for a value of 45 mmol/liter. Between-batch CV's were 8.0 and 7.1% at low total CO2, decreasing to 2.4 and 2.0% at high total CO2. Measurements were linear for values from 5 to 60 mmol/liter. Analytical recoveries at low and high concentrations were 97.7 to 98.9%. Correlation coefficients for results obtained with the Technicon "SMA Plus" autoAnalyzer and the Radiometer ABL 1 blood gas analyzer were 0.992 and 0.996, respectively. The Harleco Micro CO2 System appears to be a quick, reliable, and inexpensive method for measuring serum or plasma total CO2.

Adsorption and Conduction-Block of Opiate Narcotics on Nerve Membranes: Identical Effects of Levo- and Dextro-Forms

1972 ◽  
Vol 50 (12) ◽  
pp. 1181-1192 ◽  
Author(s):  
P. Seeman ◽  
M. Chau-Wong ◽  
S. Moyyen
Keyword(s):  
Guinea Pig ◽  
Binding Sites ◽  
Partition Coefficients ◽  
Sodium Phosphate ◽  
Conduction Block ◽  
Brain Regions ◽  
A Value ◽  
Guinea Pig Brain ◽  
Synaptosome Membrane

(1) In order to detect the possible existence of stereospecific binding sites for the opiate narcotics, the adsorption and conduction-blocking action of the enantiomers of methadone and levorphanol were tested on nerve membranes.(2) The adsorption of radioactive dextro- and levo-methadone to homogenates of guinea pig brains were identical. The addition of nonradioactive levo-methadone displaced equal amounts of the radioactive dextro- and levo-methadones.(3) Simultaneous adsorption of 3H-levo-methadone and 14C-dextro-methadone to homogenates of various brain regions also did not reveal any stereoselective adsorption of the levo-isomer.(4) In vivo perfusion of guinea pig brain with 3H-levo-methadone simultaneously with 14C-dextro-methadone did not reveal any methadone uptake which was stereoselective for the levo-isomer and which was significantly different from skeletal muscle. In vivo perfusion with 3H-dextro-methadone simultaneously with 14C-levo-methadone also did not reveal stereoselectivity for the levo-form.(5) The synaptosome membrane/buffer partition coefficients for dextro- and levo-methadone were identical, having a value of 300 at 22°, and about 430 at 37° (in 10 mM sodium phosphate, pH 7). In 0.9% NaCl, the methadone partition coefficient fell to 32 (at 22 °C). The adsorption isotherm indicated only one set of binding sites.(6) The minimum concentrations required to block impulse conduction in rat phrenic nerve were 9.5 × 10−6 M for both dextro- and levo-methadone, 2 × 10−4 M for levorphanol, and 3 × to 4 × 10−4 M for dextrorphan.(7) It is possible that the binding is not stereospecific but that it is only the efficacy on the receptor which is stereospecific.

Blood/Gas Partition Coefficients for Isoflurane, Sevoflurane, and Desflurane in a Clinically Relevant Patient Population

2015 ◽  
Vol 120 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Tobias Esper ◽  
Markus Wehner ◽  
Claus-Dieter Meinecke ◽  
Henrik Rueffert
Keyword(s):  
Patient Population ◽  
Partition Coefficients ◽  
Blood Gas

scholarly journals Effects of Pregnancy on the Solubility of Halogenated Volatile Anaesthetics in Rat Blood and Tissues

2008 ◽  
Vol 36 (6) ◽  
pp. 830-834 ◽  
Author(s):  
Y. Rao ◽  
Y.-L. Wang ◽  
H. Li ◽  
W. Zhang ◽  
J. Liu
Keyword(s):  
Gas Chromatography ◽  
Analysis Of Variance ◽  
Partition Coefficients ◽  
The Other ◽  
Blood Gas ◽  
Volatile Anaesthetics ◽  
Sprague Dawley ◽  
Tissue Samples ◽  
Rat Blood ◽  
Sprague Dawley Rats

This study was designed to evaluate the effects of pregnancy on the solubility of halogenated volatile anaesthetics in rat blood and tissues. Tissue samples from 10 pregnant and 10 non-pregnant adult female Sprague Dawley rats, including the heart, liver, kidney and brain, were obtained and made into respective homogenates. Blood/gas and tissue/gas partition coefficients for halothane, sevoflurane and isoflurane were determined by the method of two-stage headspace equilibration by gas chromatography with each of the homogenates. Values were analysed by t-test or one-way analysis of variance. The solubility within blood and brain for halothane in the pregnant group (2.90 ± 0.44, 5.55 ± 0.73) was significantly lower than that of the non-pregnant group (3.42±0.23, 6.33±0.64; P <0.05). However, there were no significant differences between the two groups for liver, kidney or heart solubility. For sevoflurane and isoflurane, there were no significant differences in solubility between the two groups. In conclusion, pregnancy decreased the solubility of halothane within the blood and brain, whereas the solubility of halothane in other tissues including the liver, kidney and heart showed no significant alteration. Pregnancy did not affect the solubility of sevoflurane or isoflurane within blood or the other tissues studied.

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