Determination of dissolved N2 in blood by gas chromatography and (a-A)N2 difference

1963 ◽  
Vol 18 (1) ◽  
pp. 97-106 ◽  
Author(s):  
L. E. Farhi ◽  
A. W. T. Edwards ◽  
T. Homma
Keyword(s):  
Technical Assistance ◽  
Biological Fluids ◽  
Venous Blood ◽  
Normal Subjects ◽  
Systematic Difference ◽  
Urine Specific Gravity ◽  
Vacuum Extraction ◽  
Arterial Blood ◽  
The Mean ◽  
Breathing Room

By combining vacuum extraction in a Van Slyke chamber and separation of the extracted gases in a gas chromatograph, it is possible to determine N2 content of 1.5 ml of blood or other biological fluids in less than 10 min. The 95% confidence limits are 0.44% on either side of the mean of the triplicate analysis-or 2.4 mm Pn2 in arterial blood when breathing room air. Application of the method to the problem of arterial-alveolar N2 difference yielded the following data: 1) N2 solubility in whole blood at 37.3 C varied from 0.0125 to 0.0129; 2) N2 solubility in urine is inversely related to urine specific gravity, confirming Klocke and Rahn's data; 3) changes in arterial N2 content were reflected in arm superficial venous blood and urine N2 only after a considerable period of time, indicating that either of these will give an excellent indication of the mean Pn2 over a period of time; 4) there is no systematic difference between venous blood and urine Pn2; 5) the (a-A)N2 difference in nine normal subjects varied from 3.7 to 13.1 mm Hg. Note: (With the Technical Assistance of M. Passke) Submitted on July 24, 1962

Plasma Cadmium and Zinc in Human Hypertension

1976 ◽  
Vol 51 (5) ◽  
pp. 483-486 ◽  
Author(s):  
G. S. Thind ◽  
Grace M. Fischer
Keyword(s):  
Significant Positive Correlation ◽  
Venous Blood ◽  
Normal Subjects ◽  
Atomic Absorption Spectrophotometry ◽  
Hypertensive Patients ◽  
Peripheral Venous Blood ◽  
Absorption Spectrophotometry ◽  
Arterial Blood ◽  
The Mean ◽  
Cadmium Zinc

1. Plasma cadmium and zinc were determined by atomic absorption spectrophotometry in inferior venal caval or peripheral venous blood in thirty hypertensive patients and fifteen normal subjects. 2. The mean plasma cadmium in hypertensive patients was significantly higher than in normal control subjects. 3. The plasma cadmium/zinc ratio was significantly greater in hypertensive patients. 4. There was a significant positive correlation between the plasma cadmium/zinc ratio and the mean arterial blood pressure.

Testosterone precursors in spermatic venous blood of normal men and varicocele patients

1985 ◽  
Vol 108 (2) ◽  
pp. 277-283 ◽  
Author(s):  
S. Andò ◽  
C. Giacchetto ◽  
G. M. Colpi ◽  
E. Beraldi ◽  
M. L. Panno ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Venous Blood ◽  
Normal Subjects ◽  
Hydroxylase Activity ◽  
Positive Correlation ◽  
Testosterone Biosynthesis ◽  
The Mean ◽  
The Individual ◽  
Normal Men

Abstract. In the present study we determined progesterone (p), 17-OH-progesterone (17-OH-P), androstenedione (Δ4), dehydroepiandrosterone (DHEA) and testosterone (T) in spermatic venous blood of 34 varicocele patients and of 13 normal subjects. We also used the DHEA/Δ4 ratio as an index of the Δ5/Δ4 pathway ratio in testosterone biosynthesis. The mean of T and Δ4 in the spermatic blood of varicocele (V) patients appeared to be significantly lower with respect to that of normal (N) subjects (T:N = 1718.2 ± 202.4 (sem) nmol/l, No. 11; V = 1243.7 ± 97 (sem) nmol/l, No. 34; P < 0.03. Δ4: N = 56.4 ± 5.6 (sem) nmol/l, No. 12; V = 38.1 ± 4 (sem) nmol/l, No. 27, 0.02> P>0.01). A negative correlation was observed between the individual age of varicocele patients and 17-OH-P (No. 34, y = −30.66x + 1300, r = −0.57, P < 0.01) Δ4 values (No. 27, y = −1.981x + 96.52, r = −0.67, P< 0.01). When the ratio of T precursors was evaluated, we observed a positive correlation between the P/17-OH-P ratio and age of varicocele (No. 33, y = 0.0065x–0.092, r = 0.45, P < 0.03). The 17-OH-P/Δ4 ratio was greatly increased with respect to that of normal subjects (N = 5.12 ± (sem), No. 12; V= 10.77 ± 1.31 (sem), No. 27; P<0.01). These data suggest that the reduced T levels in spermatic venous blood of varicocele patients were due firstly to the enzymatic deficiency of 17-20-lyase and secondly to that of 17α-hydroxylase activity as the patients grow relatively older. The negative correlation between the DHEA/Δ4 ratio and Δ4/T ratio was observed in normal subjects (No. 10, y = −0.00432x + 0.0542, r = −0.67, P < 0.03) as well as in varicocele patients (No. 27, y = −0.00399x + 0.0587, r = −0.48, 0.02 > P > 0.01). This indicates that in the testis of varicocele patients the testosterone remains prevalently supplied by the Δ5 pathway of biosynthesis.

Determination of the pH of Hemolyzed Packed Red Cells from Arterial Blood

1961 ◽  
Vol 7 (5) ◽  
pp. 536-541 ◽  
Author(s):  
May K Purcell ◽  
Gertrude M Still ◽  
Theodore Rodman ◽  
Henry P Close
Keyword(s):  
Blood Cell ◽  
Normal Subjects ◽  
The Body ◽  
Red Cell ◽  
Arterial Blood ◽  
Fiducial Probability ◽  
The Mean ◽  
Red Cell Ph

Abstract A technic is described for the determination of the in vivo pH of red blood cell hemolysates. The mean arterial red cell pH of 20 normal subjects was 7.19 with a range of 7.15 to 7.22. The fiducial probability at the 0.95 level is 7.13 to 7.25. The mean difference in pH between plasma and cells was 0.21, with a range of 0.15 to 0.23. It is suggested that changes in pH of erythrocytes may reflect changes in other less accessible cells of the body and that the determination may be a useful research and clinical procedure in the study of metabolic and respiratory derangements.

scholarly journals The irreversible loss of alanine and of glycine in fetal and sucking lambs

1984 ◽  
Vol 52 (3) ◽  
pp. 529-543 ◽  
Author(s):  
G. M. Hatfield ◽  
Jenny Joyce ◽  
Marjorie K. Jeacock ◽  
D. A. L. Shepherd
Keyword(s):  
Specific Activity ◽  
Single Injection ◽  
Venous Blood ◽  
Injection Technique ◽  
Irreversible Loss ◽  
Fetal Tissues ◽  
Arterial Blood ◽  
Pool Model ◽  
The Mean ◽  
Mean Concentration

1. Estimates have been made of the irreversible loss of alanine and of glycine in chronically catheterized fetal lambs and in sucking lambs using [U-14C]-labelled radioisotopes. The experiments in the fetal lambs were carried out at least 5 d after implantation of catheters.2. The mean concentration of glycine in fetal femoral arterial blood between 102 and 129 d conceptual age was 755 μmol/l and this was not significantly different from that in maternal venous blood. The mean concentration of alanine in fetal femoral arterial blood during the same period of gestation was 229μmol/l and this was significantly greater than that in maternal venous blood.3. Assuming a catenary model, the mean irreversible loss of glycine, determined using the single-injection technique, in three fetal lambs of 107, 111 and 127 d conceptual age was 17 μmol/min per kg, whereas in two fetal lambs aged 106 and 109 d into which the isotope was infused continuously the mean irreversible loss, calculated from the specific activity of glycine 5 h after the start of infusion of the tracer ('pseudo plateau'), was 12 μmol/min per kg. In a sucking lamb, 9 d after birth, the irreversible loss of glycine was 11 μmol/min per kg. The mean irreversible loss of alanine, determined by the single-injection technique assuming a catenary model in five fetuses between 112 and 121 d conceptual age was 14μmol/min per kg, and in two sucking lambs, 9 and 11 d after birth, it was 5.1 μmol/min per kg.4. When a two-pool model was assumed in which entry of metabolite was not directly into the sampling pool but was by way of the second pool, then the mean irreversible loss of glycine in the three fetuses was 23 μmol/min per kg and of alanine in the five fetuses was 32 μmol/min per kg. Calculations based on the alternative two-pool model did not alter appreciably the rates of irreversible loss of either alanine or glycine in the sucking lambs.5. From a comparison of the specific activities of the amino acids and of carbon dioxide in blood during the course of the experiments, it was found that in the fetuses 0.96% of the CO2 present in blood was derived from alanine and only 0.12% was derived from glycine. It was calculated that not more than 1.6 μmol lanine/min per kg and 0.29 μmol glycine/min per kg could have been converted to CO2 in the fetal lambs.6. It is concluded that since glycine in fetal blood originates from fetal tissues and not from direct transfer across the placenta the upper value for the irreversible loss describes metabolism best. In the case of alanine, which is derived from both the maternal circulation and from metabolism in fetal tissues, the true rate of irreversible loss must lie between the values predicted by the two models.

Pharmacokinetics and Arteriovenous Differences in Clevidipine Concentration following a Short- and a Long-term Intravenous Infusion in Healthy Volunteers

2000 ◽  
Vol 92 (4) ◽  
pp. 993-1001 ◽  
Author(s):  
Hans Ericsson ◽  
Ulf Bredberg ◽  
Ulf Eriksson ◽  
Åse Jolin-Mellgård ◽  
Margareta Nordlander ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Steady State ◽  
Healthy Volunteers ◽  
Venous Blood ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Blood Levels ◽  
Blood Concentrations ◽  
Arterial Blood ◽  
The Mean

Background Clevidipine is an ultra-short-acting calcium antagonist developed for reduction and control of blood pressure during cardiac surgery. The objectives of the current study were to determine the pharmacokinetics of clevidipine after 20-min and 24-h intravenous infusions, and to determine the relation between the arterial and venous concentrations and the hemodynamic responses to clevidipine in healthy volunteers. Methods Four volunteers received clevidipine for 20 min, and eight subjects were administered clevidipine intravenously for 24 h at two different dose rates. Arterial and venous blood samples were drawn for pharmacokinetic evaluation, and blood pressure and heart rate were recorded. Results A triexponential disposition model described the pharmacokinetics of clevidipine. The mean arterial blood clearance of clevidipine was 0.069l/kg-1/min-1 and the mean volume of distribution at steady state was 0.19 l/kg. The duration of the infusion had negligible effect on the pharmacokinetic parameters, and the context-sensitive half-time for clevidipine, simulated from the mean pharmacokinetic parameters derived after 24 h infusion at the highest dose, was less than 1 min. The arterial blood levels reached steady state within 2 min of the start of infusion and were about twice as high as those in the venous blood at steady state. The peak response preceded the peak venous concentration and was slightly delayed from the peak arterial blood concentration. Conclusion Clevidipine is a high clearance drug with a small volume of distribution, resulting in extremely short half-lives in healthy subjects. The initial rapid increase in the arterial blood concentrations and the short equilibrium time between the blood and the biophase suggest that clevidipine can be rapidly titrated to the desired effect.

Effects of hyperoxia on maximal leg O2 supply and utilization in men

1993 ◽  
Vol 75 (6) ◽  
pp. 2586-2594 ◽  
Author(s):  
D. R. Knight ◽  
W. Schaffartzik ◽  
D. C. Poole ◽  
M. C. Hogan ◽  
D. E. Bebout ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Venous Blood ◽  
Normal Subjects ◽  
Constant Infusion ◽  
Venous Blood Flow ◽  
O2 Uptake ◽  
Fick Principle ◽  
The Mean ◽  
O2 Supply ◽  
O2 Delivery

We studied O2 transport in the leg to determine if hyperoxia will increase the maximal rate of O2 uptake (VO2max) in exercising muscle. An increase in inspired O2 fraction (FIO2) from 0.21 to 1.00 was postulated to have the following effects: 1) increase the leg VO2max by approximately 5–10%, 2) increase the maximal O2 delivery [arterial O2 concentration.flow (CaO2.Q] by approximately 10%, and 3) raise the leg VO2max in proportion to both the femoral venous PO2 and mean leg capillary PO2. To test these hypotheses, 11 men performed cycle exercise to the highest work rates (WRmax) they could achieve while breathing 100% O2 (hyperoxia), 21% O2 (normoxia), and 12% O2 (hypoxia). Leg VO2 was derived from duplicate measurements of femoral venous blood flow and CaO2 and femoral venous blood O2 concentrations (CVO2) at 20, 35, 50, 92, and 100% WRmax in each FIO2. Femoral venous leg Q (Qleg) was measured by the constant-infusion thermodilution technique, and leg O2 uptake (VO2) was determined by the Fick principle [VO2 = Qleg(CaO2-CVO2)]. Leg VO2max was the mean of duplicate values of VO2 at 100% WRmax for each FIO2. Hyperoxia increased leg VO2max by 8.1% (P = 0.016) and maximal O2 delivery by 10.9% (P = 0.05) without changing Qleg. There was a significant increase in femoral venous PO2 (P < 0.001) that was proportionally greater than the increase in leg VO2max. The results support our first and second hypotheses, providing direct evidence that in normal subjects leg VO2max is limited by O2 supply during normoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxygen tensions measured in cat cerebral cortex under hyperbaric conditions

1979 ◽  
Vol 46 (1) ◽  
pp. 53-60 ◽  
Author(s):  
F. G. Hempel
Keyword(s):  
Cerebral Cortex ◽  
Venous Blood ◽  
Sagittal Sinus ◽  
Venous Circulation ◽  
Arterial Blood ◽  
The Mean ◽  
Oxygen Tensions ◽  
The Brain ◽  
Cat Cerebral Cortex ◽  
Hyperbaric Conditions

Pyrenebutyric acid (PBA), the intracellular fluorescent indicator, was used to measure the partial pressure of oxygen (PO2) in the exposed cerebral cortex of anesthetized cats at hyperbaric pressures up to 4 ATA. The validity of the PBA method for determining cortical PO2 was confirmed by demonstrating a precise linear relationship between Pao2 and the reciprocal of the fluorescence of PBA in the brain as the cat was ventilated with sequentially greater oxygen pressures while holding the Paco2 nearly constant. Increments in the Paco2 while the Pao2 was maintained at a high (about 2,000 Torr) level resulted in stepwise greater oxygen tensions in the brain until an oxygenation end point was reached with a Paco2 averaging near 122 Torr. Greater amounts of CO2 did not bring the mean PO2 of the brain, 1,017 Torr, closer to 2,000 Torr. During normocapnia the cortical PO2 was greater than the PO2 of cerebral venous blood collected from the superior sagittal sinus; however, in hypercapnia (PaCO greater than 45 Torr), the PO2 of the sinus blood exceeded the value determined in the cortex. This latter observation is taken as evidence for convective shunting of cerebral arterial blood to venous circulation when hypercapnia is present.

Validation of Oxygen Saturation Monitoring in Neonates

2007 ◽  
Vol 16 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Shyang-Yun Pamela K. Shiao ◽  
Ching-Nan Ou
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Venous Blood ◽  
Arterial Oxygen ◽  
Dissociation Curve ◽  
Oxyhemoglobin Dissociation Curve ◽  
Blood Samples ◽  
Arterial Blood ◽  
The Mean ◽  
Oxyhemoglobin Dissociation

•Background Pulse oximetry is commonly used to monitor oxygenation in neonates, but cannot detect variations in hemoglobin. Venous and arterial oxygen saturations are rarely monitored. Few data are available to validate measurements of oxygen saturation in neonates (venous, arterial, or pulse oximetric). •Purpose To validate oxygen saturation displayed on clinical monitors against analyses (with correction for fetal hemoglobin) of blood samples from neonates and to present the oxyhemoglobin dissociation curve for neonates. •Method Seventy-eight neonates, 25 to 38 weeks’ gestational age, had 660 arterial and 111 venous blood samples collected for analysis. •Results The mean difference between oxygen saturation and oxyhemoglobin level was 3% (SD 1.0) in arterial blood and 3% (SD 1.1) in venous blood. The mean difference between arterial oxygen saturation displayed on the monitor and oxyhemoglobin in arterial blood samples was 2% (SD 2.0); between venous oxygen saturation displayed on the monitor and oxyhemoglobin in venous blood samples it was 3% (SD 2.1) and between oxygen saturation as determined by pulse oximetry and oxyhemoglobin in arterial blood samples it was 2.5% (SD 3.1). At a Pao2 of 50 to 75 mm Hg on the oxyhemoglobin dissociation curve, oxyhemoglobin in arterial blood samples was from 92% to 95%; oxygen saturation was from 95% to 98% in arterial blood samples, from 94% to 97% on the monitor, and from 95% to 97% according to pulse oximetry. •Conclusions The safety limits for pulse oximeters are higher and narrower in neonates (95%–97%) than in adults, and clinical guidelines for neonates may require modification.

Blood Gases of the Tench (Tinca tinca) in Well Aerated and Oxygen-Deficient Waters

1974 ◽  
Vol 60 (1) ◽  
pp. 71-83 ◽  
Author(s):  
F. B. EDDY
Keyword(s):  
Venous Blood ◽  
Oxygen Affinity ◽  
Blood Gases ◽  
Mean Value ◽  
Hypoxic Conditions ◽  
Arterial Blood ◽  
The Mean ◽  
Tench Tinca Tinca

1. The respiration of tench at 13°C was investigated, particular attention being given to the role of the blood in uptake and transport of oxygen. 2. In well aerated water the mean value for arterial blood was 36 mmHg, for PCOCO2 3.3 mmHg and for pH 8.16; the respective venous values were 7 mmHg, 5 mmHg and 8.08. Arterial blood averaged about 75% and venous blood about 40° oxygen saturation. The mean value for oxygen uptake was 0.5 ml/min/kg and for ventilation volume 132/ml/mm/kg. 3. The oxygen tension and the percentage saturation of the blood determined in vivo are discussed in terms of the oxygen dissociation curve determined in vitro. 4. When the environmental POO2 was decreased, tench responded by increasing breathing rate and ventilation volume. Arterial POO2 and PCOCO2 decreased but arterial pH tended to remain steady. There was also a significant increase in blood lactate. 5. That tenth can withstand severe hypoxic conditions is attributed to blood of high oxygen affinity and the ability to maintain a favourable acid-base status in the blood for oxygen transport. 6. Respiration in tench is compared with that in other fish species.

scholarly journals Can peripheral venous blood gases replace arterial blood gases in emergency department patients?

CJEM ◽  
2002 ◽  
Vol 4 (01) ◽  
pp. 7-15 ◽  
Author(s):  
Louise C.F. Rang ◽  
Heather E. Murray ◽  
George A. Wells ◽  
Cameron K. MacGougan
Keyword(s):  
Venous Blood ◽  
Correlation Coefficients ◽  
Blood Gases ◽  
Blood Gas ◽  
Emergency Physicians ◽  
Peripheral Venous Blood ◽  
Arterial Blood ◽  
The Mean ◽  
Mean Differences ◽  
Venous Blood Gas

ABSTRACTObjective:To determine if peripheral venous blood gas values for pH, partial pressure of carbon dioxide (PCO2) and the resultant calculated bicarbonate (HCO3) predict arterial values accurately enough to replace them in a clinical setting.Methods:This prospective observational study was performed in a university tertiary care emergency department from June to December 1998. Patients requiring arterial blood gas analysis were enrolled and underwent simultaneous venous blood gas sampling. The following data were prospectively recorded: age, sex, presenting complaint, vital signs, oxygen saturation, sample times, number of attempts and indication for testing. Correlation coefficients and mean differences with 95% confidence intervals (CIs) were calculated for pH,PCO2and HCO3. A survey of 45 academic emergency physicians was performed to determine the minimal clinically important difference for each variable.Results:The 218 subjects ranged in age from 15 to 90 (mean 60.4) years. The 2 blood samples were drawn within 10 minutes of each other for 205 (96%) of the 214 patients for whom data on timing were available. Pearson’s product–moment correlation coefficients between arterial and venous values were as follows: pH, 0.913;PCO2, 0.921; and HCO3, 0.953. The mean differences (and 95% CIs) between arterial and venous samples were as follows: pH, 0.036 (0.030–0.042);PCO2, 6.0 (5.0–7.0) mm Hg; and HCO3, 1.5 (1.3–1.7) mEq/L. The mean differences (± 2 standard deviations) were greater than the minimum clinically important differences identified in the survey.Conclusions:Arterial and venous blood gas samples were strongly correlated, and there were only small differences between them. A survey of emergency physicians suggested that the differences are too large to allow for interchangeability of results; however, venous values may be valid if used in conjunction with a correction factor or for trending purposes.

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