Gas Analysis Apparatus Research Articles

Time-dependent changes in epidural catheter aspirate after injection of a local anesthetic

Study objectiveA glucose check is used for investigation of a suspected accidental dural puncture in epidural anesthesia. However, glucose-positive clear fluid is sometimes aspirated from an epidural catheter in cases without clinical evidence of puncture. The goal of the study was to investigate time-dependent changes in the aspirate composition after injection of a local anesthetic into the epidural space. DesignObservational study. SettingOperating rooms at Hamamatsu University Hospital. PatientsThe subjects were 30 patients (ASA I or II) undergoing surgery with combined epidural and general anesthesia. InterventionsAfter epidural injection of local anesthetics, aspiration through the catheter was performed every 10min until fluid could not be aspirated. pH, Na, K, Cl, Ca and glucose were measured in fluid samples using a blood gas analysis apparatus. Main resultsNo patients had pain or clinical signs suggesting dural puncture throughout the perioperative period. Fluid aspiration was possible in 15 patients (50%) after 10min and in 7, 3, 2 and 2 patients after 20, 30, 40 and 50min, respectively. Glucose was detected in each aspirated fluid sample and gradually increased with time to become closer to the level in cerebrospinal fluid (CSF). Each electrolyte also changed to approach the level found in CSF. ConclusionsA glucose check may increase the risk of a false-positive finding for accidental dural puncture with increasing time after local anesthetic injection. Conversely, detection of glucose at the time of epidural catheter placement may provide useful information for detection of accidental dural puncture.

The invention and development of blood gas analysis apparatus.

In 1953, the doctor draft interrupted Dr. Severinghaus' anesthesia and physiology training and sent him to the National Institutes of Health as director of anesthesia research at the newly opened Clinical Center. He developed precise laboratory partial pressure of carbon dioxide (PCO(2)) and pH analysis to investigate lung blood gas exchange during hypothermia. Constants for carbon dioxide solubility and pK' were more accurately determined. In August 1954, he heard Richard Stow describe invention of a carbon dioxide electrode and immediately built one, improved its stability, and tested its response characteristics. In April 1956, he also heard Leland Clark reveal his invention of an oxygen electrode. Dr. Severinghaus obtained one and constructed a stirred cuvette in which blood partial pressure of oxygen (PO(2)) could be accurately measured. Technician Bradley and Dr. Severinghaus combined these, making the first blood gas analysis system in 1957 and 1958, and shortly thereafter, they added a pH electrode. Blood gas analyzers rapidly developed commercially. Dr. Severinghaus collaborated with Astrup and other Danes on the Haldane and Bohr effects and their concepts of base excess during two sabbaticals in Copenhagen. Work with both Astrup and Roughton on the oxygen dissociation curve led Dr. Severinghaus to devise a modified Hill equation that closely fit their new, better human oxygen dissociation curve and a blood gas slide rule that solved oxygen dissociation curve, PCO(2), pH, and acid-base questions. Blood gas analysis revolutionized both clinical medicine and cardiorespiratory and metabolic physiology.

Measurement of cardio-respiratory function using single frequency inspiratory gas concentration forcing signals.

The possibility of using inspiratory, oscillating inert gas concentration forcing signals to measure the average lung ventilation-perfusion ratio was proposed by Zwart and colleagues (1976, 1978). These authors used halothane as the forcing gas, at sub-anaesthetic concentra­tions around 0.02% v/v, but this introduced severe measurement problems at these very low concentrations. Recently Hahn et al (1993) have described a similar but improved respiratory model which uses nitrous oxide (N2O) as the forcing gas. The advantages of nitrous oxide over halothane are that it is free from biological toxicity; it is easy to measure N2O with conventional gas analysis apparatus (especially at the concentrations used by Hahn et al (1993), around 2–10% v/v); and because nitrous oxide can be measured continuously in blood, the mathematical model can be extended to include shunt blood flow. In this technique, a three-compartment continuous ventilation mathematical model describes the imposition of a forced oscillating inspired inert gas concentration, Pi(t), which oscillates sinusoidally over a range of frequencies (0.6 to 6 min-1), and the subsequent measurement of the attenuation of the end-expired inert gas concentration, Pe(t), with changing forcing frequency (Figure 1). The plot of Pe/Piagainst forcing frequency (the Bode plot) is then used to derive alveolar volume, Va, and pulmonary blood flow, Qp. Dead space, Vds, is derived from the sinusoidal mixed expired indicator gas signal. We have further modified this technique by using a single forcing monosinusoid (forcing frequency 0.5 min-1) of two inert gases to measure cardio-respiratory lung function. This binary inert gas oscillation technique uses Argon, which is relatively insoluble in blood, to derive alveolar volume and dead space; and nitrous oxide, which is soluble in blood, to measure pulmonary blood flow.

Alteration of Air Composition in Containers as a Result of the Extended Holding of Poultry Offal

Broiler offal, in its normal composition ratio, was collected and placed in 20-cm diameter, cylindrical containers (40-liter) half covered and half uncovered. Containers were held at 21.0 C or in a field house at temperatures cycled from 21.0 to 29.5 C. The ratio of poultry offal weight to container volume was 1:35 (w/v). The air near the center of the containers was sampled and analyzed with various Kitagawa gas detector tubes and with an Orsat gas analysis apparatus after 0, 2, 4, and 6 days of holding.With the presence of offal, the oxygen in the containers decreased continuously as the holding time increased. After 4 days, the oxygen in the container held at 21.0 C decreased to 8.00 and 12.80% for those with and without lids; in hot summer (cycled 21.0 to 29.5 C) conditions, these oxygen values were 6.36 and 11.88%, respectively. Free ammonia in the covered containers increased from nondetectable to 232.0 and 310.8 ppm after 4 days of holding at 21.0 and in 21.0 to 29.5-cycled conditions, respectively. However, little or no free ammonia was detected from the containers without lids. An increase in hydrogen sulfide and carbon dioxide contents was also observed in the covered containers. Results suggested that the residues of offal in the transporting container could be a hazard for public safety during the hot summer season.

Energy balance study in Singapore medical students.

Energy cost of rest and various common daily activities was measured in 7 male and 16 female medical students by using a Max-Planck respirometer and a Lloyd's gas analysis apparatus. The average weight of male and female subjects during the course of the study was 67.3 +/- 14.2 and 51.2 +/- 5.1 kg, respectively. The average energy expenditure per day was estimated from a diary of activities for a period of 7 days. The average daily intake of energy was computed from food tables and based on weighed amounts of raw materials of food consumed over the same 7-day period when energy expenditure was determined. The average energy expenditure of rest and different activities was found to be significantly lower than the figures published for western subjects. The daily energy intake and expenditure were 2,138 +/- 217 kcal (9.0 +/- 0.9 MJ) and 1,894 +/- 168 kcal (8.0 +/- 0.7 MJ), respectively, in male medical students, giving a positive balance of 244 kcal (1.0 MJ). The values of the same in female medical students were 1,711 +/- 292 kcal (7.2 +/- 1.2 MJ) and 1,474 +/- 211 kcal (6.2 +/- 0.9 MJ) with a balance of 237 kcal (1.0 MJ).

Nutrient and productivity relations of the dune grasses Ammophila arenaria and Elymus mollis : I. Blade photosynthesis and nitrogen use efficiency in the laboratory and field.

A comparative study of blade photosynthesis and nitrogen use efficiency was made on the dune grasses Ammophila arenaria and Elymus mollis. In the laboratory, an open system gas analysis apparatus was used to examine the gas exchange characteristics of blades as influenced by nitrogen supply. Plants were grown under near-ambient coastal conditions in a greenhouse near Bodega Bay, California, and given either high or low supplies of nitrogen in an otherwise complete nutrient solution. In the field, 14CO2 uptake techniques were employed to measure the seasonal patterns of blade photosynthesis of plants growing in situ at Point Reyes National Seashore. Blades used in the lab and field studies were analyzed for total nitrogen content, thus allowing for calculations of photosynthetic nitrogen use efficiency (CO2 fixed/unit of blade N.).Under laboratory conditions, the introduced Ammophila developed higher rates of light-saturated photosynthesis than the native Elymus, especially under the nitrogenlimited growth regime. Higher rates of photosynthesis and lower concentrations of blade N resulted in a significantly greater nitrogen use efficiency for Ammophila regardless of nutrient treatment. Low N availability induced qualitatively similar physiological responses in both species, including reductions in maximum net photosynthesis, mesophyll conductance, leaf conductance, dark respiration, and blade nitrogen content, and an increase in the CO2 compensation point.Although the photosynthetic rates of Ammophila blades were higher in the lab, those of Elymus blades were consistently higher in the field. This could have resulted from differential effects of drought on the two species (i.e. Ammophila may have been more sensitive) or a higher photosynthetic capacity in Elymus that reflected the greater (1.2-1.5 X) nitrogen content of its blades. However, the nitrogen use efficiency of Ammophila blades was greater than that of Elymus throughout most of the sampling year, despite lower average rates of field photosynthesis.The results indicated that rates of photosynthesis perunit of blade area do not account for the greater aboveground productivity of Ammophila stands along the Pacific coast of North America. Instead, efficient nitrogen use in photosynthesis maycomplement other structural and physiological traits and thereby enhance long-term carbon gain in Ammophila relative to Elymus.

A new ventilator for physiologic studies during high-frequency ventilation

Research in the field of high frequency ventilation (HFV) has been hampered by the difficulty of collecting and analyzing expired gas, uncontaminated by gas of inspiratory composition, at ventilatory frequencies in the relevant range. A new mechanical ventilator is descrbied, which has been designed to facilitate studies on the respiratory physiology of small animals during HFV. Ventilation is controlled by an single rotary valve, which alternately switches the airway to an approximately constant-flow gas source during inspiration, and to gas measurement and analysis apparatus during expiration, which takes place passively. Theoretical and experimental studies, using the techniques of mechanical and methematical modelling, are used to measure the performance of the ventilator and to demonstrate that it allows the quantitative collection of expired gas during ventilation at rates up to least 20 Hz. The advantages and limitations of this approach are discussed.

A new device of the gas analysis apparatus for the samples from a living body with the permeation tube and gas chromatograph (I)

A new device of the gas analysis apparatus for the samples from a living body with the permeation tube and gas chromatograph (I)

A new device of gas analysis apparatus for biological samples with a combination of permeation tube and gas chromatograph(II); Application to blood

A new device of gas analysis apparatus for biological samples with a combination of permeation tube and gas chromatograph(II); Application to blood

Development of the differential gas analysis apparatus

A modified gas effluent analysis apparatus is combined with a high-precision gas mixer to be extensively applied to the study of the gas-solid reaction involving not only evolution but absorption of gases and also to the measurement of physico-chemical change of solid. The sample is heated or cooled at the constant rate in a mixed flow of two or more different gases such as He-O2, He-CO2 Ar-H2, etc. The change in the composition of the gas passing through the reactor, due to the decomposition or the gas-solid reaction, are detected at a high sensitivity by a thermal conductivity detector. The sample weight required for the usual measurement is 550 mg. It is applicable to the range from room temperature to 1600°C and the gas flow of any mixing ratio. Although the limits of determination are affected by the operating conditions, an increase or decrease of 0.010.0001 ml of oxygen in the He-O2 mixtures can be detected.

Changes in the Carpenter Modification of the Haldane Gas Analysis Apparatus

The construction of the Carpenter modification of the Haldane gas analysis apparatus for analyzing expired air has been changed to make it sturdier and simplify its operation. Also, a new solution is used as oxygen absorbent to speed the analysis of expired air. The apparatus, in its present form, is a useful and essential tool to analyze reference gases for mechanical gas analyzers.

A versatile gas analysis apparatus incorporating a small mass spectrometer

A gas analysis apparatus is described consisting of a metal vacuum system which includes a mass spectrometer, connected by a capillary leak to a glass vacuum system which can be readily modified to suit any particular problem. This arrangement provides for a wide variety of experiments, examples of which are the analysis of small quantities of gas such as occur in bubbles in glass, desorption studies and vacuum fusion analysis. The minimum quantity of gas that is detectable with this apparatus is approximately 5 1. μtorr. The mass spectrometer may also be used as a leak detector with a detection limit of 0.1 1. ntorr sec-1.

チタンおよびチタン合金とガスとの反応の動力学的研究（第1報）工業用純チタン中水素の離脱反応について

A series of experimental studies was performed on the kinetics of reaction of commercially pure Ti and Ti alloys with the gas phases, H2, O2 and N2. This paper is the report of the investigation on the desorption of H2 from commercially pure Ti. Sponge Ti prepared by the Kroll process was arc melted by the consumable double-melting method, and the ingot was forged at 800° to a rod of 25 mm in diameter, which was annealed in argon atmosphere at 700°. Specimens of several sizes were made from the above rod and were degassed in vacuo of 1×10−4 mmHg at 700°, 750°, 800°, 850° and 900°. The evolved hydrogen was collected by means of a Beutell’s pump and measured with a micro-Oelsat gas analysis apparatus. It was found that the logarithms of the concentration of hydrogen in metals were decreased in linear relation with time at any temperature, and from these relations the diffusion constant D was calculated by Al Demarez’s formula. The temperature dependence of D in α Ti offered by us is given by D_α=0.27 ×10^-2 exp(-14,200/RT) When the above value is compared to those of iodide Ti determined by Wasilewski, we find a slight discrepancy, which is considered due to impurities (i.e. Fe, Si, N, O, etc.) contained in commercially pure Ti used in our experiments.

Improved gasometric methods for estimating oxygen content and percentage saturation in haemoglobin dissociation curve determinations.

By using carbon monoxide as a reagent for releasing oxygen from blood solutions (instead of the customary potassium ferricyanide) and by combining the techniques of the Van Slyke constant-volume gasometric apparatus and the Scholander gas analysis apparatus, a precise method has been devised of estimating oxygen content and carbon monoxide capacity simultaneously on one and the same sample of blood solution. The procedure eliminates various errors inherent in the determination of oxygen percentage saturation, when oxygen content and capacity are successively measured on separate samples. The method has been extensively tested on sheep blood solutions containing 3 to 4 g haemoglobin/100 ml. and is considered to give an accuracy of ± 0.5 in the oxygen percentage saturation of such solutions. In its present form the method is only applicable to solutions containing a negligible amount of dissolved nitrogen, but it is probable that this restriction could be removed by the simple addition to the technique suggested in the text. Modifications are also described in the usual tonometer technique for equilibrating blood solutions with various pressures of oxygen, and for transferring the equilibrated blood solution to the Van Slyke apparatus for analysis. The techniques of the present paper have been specially used for obtaining oxyhaemoglobin dissociation curve data of higher accuracy than hitherto available. From these improved data it has for the first time been possible to calculate directly, and in many cases with fair precision, the values o f the equilibrium constants of the four successive reactions of haemoglobin with oxygen.

THE CHEMICAL CORROSION RESISTANCE OF COMMERCIALLY PURE TITANIUM AND THE INFLUENCE OF ITS CARBON CONTENT ON THE PROPERTY

The influences of carbon content on the various properties of commercial pure titanium have been studied in our laboratory, and the report on the effects of carbon on the mechanical properties, fabricating properties and heat treatment properties was already published in the "Light Metals", No. 12 (Aug., 1954 issue).This paper reports on the influence of carbon on the chemical coroosion resistance on the commercially pure titanium.Titanium, which has excellent chemical corrosion resistance, is being utilized as a construction material in the field of chemical, petroleum and synthetic fibre industries in the place of the conventional corrosion resistant metals such as stainless steel, stellite and hastelloy. And reflecting the situation, various reports on the chemical corrosion properties of titanium have already appeared in domestic and foreign literatures.We, also, conducted experiments on the property using the commercially pure titanium which was produced in our plant. Compared with previous papers on corrosion properties, our report is characterized in the following points:(1) The influence of carbon on the corrosion properties was studied.(2) The standard single electrode potential of titanium and other metal was calculated, and the corrosion resistance of titanium was examined from that view point.(3) The hydrogen and oxygen contents in specimens were analysed by the N. R. C. vacuum fusion gas analysis apparatus before and after dipping test.As the result we obtained the following conclusion:(1) Kobe Steel Work's titanium has excellent corrosion resistance against almost all chemical reagents except the following cases: a. HCl 20°C, >90%; boil, >1% e. AlCl3 boil, >25% b. HF f. Oxalic acid boil, >0.5% c. H2SO4 20°C, >70%; boil; >1% g. Formic acid boil, >25% d. H3PO4 boil, >10% h. Trichlor acetic acid 100°C 100%(2) Carbon content in the specimens has no influence on the corrosion propreties when in the range of 0.05-0.12%.(3) As the result of theoretical calculation of the standard single electrode potential, it was clarified that the position of titanium in the ionization series was between aluminium and zinc.(4) By means of gas analysis by the N. R. C. vacuum fusion gas analysis apparatus it was confirmed that-a. When titanium was dipped in the nonoxidizing acid such as HCl or H2SO4, the hydrogen content in the specimens increased remarkably, while oxygen content after dipping was nearly equal as before dipping.b. When titanium was dipped in the oxidizing acid such as HNO3, both hydrogen and oxygen contents did not increase and kept the original value.

Apparatus for the determination of the energy exchange of calves and of sheep

1. Details are given of the construction of one open-circuit and two closed-circuit respiration chambers suitable for the determination of the 24 hr. exchange of energy of calves or of other animals weighing up to 75 kg.2. Gas analysis apparatus and the general technique employed in experiments with the closedcircuit apparatus are described.3. From experience gained with both types of apparatus the closed-circuit apparatus is preferred for its simplicity and ease of working.

A reciprocating mercury pump for gas analysis apparatus

A reciprocating mercury pump which is used to mechanize the Haldane type of gas analysis apparatus is described. This pump unit, being simple and robust in construction, has proved reliable for continuous routine use.

A semi-micro gas analysis apparatus for the determination of the permanent gases

A semi-micro gas analysis apparatus for the determination of the permanent gases

Some errors in gas analysis using the Haldane apparatus

1. The paper represents an attempt to estimate the error of the standard 10 ml. Haldane gas analysis apparatus under routine conditions of use.2. The ultimate error of the instrument under optimum conditions has been obtained from duplicate mercury calibrations of the same instrument and corresponds tos.d.= 0·013% gas. A significant day-to-day variation in calibration was found.3. The accuracy in routine use has been determined by replicate estimations of CO2and O2in air and from estimation of CO2in designed experiments. The data show an error corresponding tos.d.= 0·027 to 0·13%. This is far larger than that described by Haldane.4. Examination of the distribution of terminal digits in burette readings shows that the smallest scale division is in fact not being divided into ten parts by the worker. Preference for certain digits varies with the individual, with time, and with the accuracy required.5. There is a marked tendency for a worker to obtain an ‘expected result’, whether this is derived from a previous estimation of the same sample or from knowledge of the expected result; such bias tends to reduce the apparent error of estimation. Bias of replication—‘prejudice error’—may play a part in many forms of measurement.6. The results and conclusions are discussed in relation to other published data on errors of measurement in general.

A SIMPLE GAS ANALYZER

The gas analysis apparatus described is similar to an enlarged version of Krogh's microapparatus. It consists of a 1 cc. burette calibrated in one-hundredths, enclosed in a water jacket joined above to a glass funnel through a short capillary and below to a mercury reservoir. The absorbing solutions are placed in the glass funnel above, and the gas sample is injected through a needle inserted into a rubber cap on a side arm of the mercury reservoir.The apparatus is simple in design and in use, is easy to clean, and the cost is low. Accuracy is approximately ± 0.5%. A modified analyzer has been used by students with satisfactory results.