Minute Flow Rates Research Articles

Ventilatory response during CO2 inhalation after airway anesthesia with lidocaine.

Airway anesthesia with inhaled aerosolized lidocaine has been associated with increases in minute ventilation (VE) and mean inspiratory flow rate (VT/TI) during CO2 inhalation. However, it is unclear whether these increases are local effects of the anesthesia or systemic effects of absorbed and circulating lidocaine. To evaluate this 20 normal subjects were treated on separate days with aerosolized lidocaine, intravenous lidocaine, aerosolized control solution, or intravenous control solution, and the effects of each treatment on VE and VT/TI were determined and compared during room-air breathing and inhalation of 5% CO2-95% O2. None of the treatments altered VE or VT/TI during room-air breathing. Aerosolized lidocaine produced small (5.9-6.0%) increases in VE and VT/TI during CO2 inhalation, but these effects were not present after intravenous lidocaine despite equivalent lidocaine blood levels. We concluded that the increases in VE and VT/TI after aerosolized lidocaine were local effects of airway anesthesia rather than systemic effects of absorbed and circulating lidocaine.

Evaluation of an Emergency Drive System for a Disabled Arterial Pump Head

This study evaluates an Emergency Drive System (E.D.S.) developed by the authors to provide an electrically powered drive system for a disabled arterial pump head. The methods used in this study were designed to evaluate the E.D.S. under simulated clinical conditions using an American Optical Model 16655 pump with 1/2″ tubing in the arterial pump head and a Sarns 5000 pump with 3/8″ tubing in the arterial pump head. The E.D.S. was applied to the .arterial pump head and was required to produce a six liter per minute flow based on the revolutions per minute of the pump head. The study was deemed successful if the E.D.S. was capable of providing the revolutions per minute for a two hour period. The E.D.S. was capable of providing the 100 revolutions per minute for American Optical pump and the 230 revolutions per minute for the Sarns 5000 pump, necessary to produce a six liter per minute flow rate. In conclusion our study shows the E.D.S. is an easy and accurate device for providing temporary power to a disabled arterial pump head.

THE PERFORMANCE OF A SCAVENGING VALVE

A simple, compact and lightweight device for coupling active scavenging systems to shrouded breathing system valves is described. Provided a scavenging minute flow rate greater than the expired gas volume is available, the unit can handle automatically changes in both variables. Optimal function is achieved with scavenging flows from about twice the discharged gas flow to about 50 litre min-1. At these flows the valve can accommodate the outflow of gas-driven ventilators where driving gas and circuit gas are discharged through the same port. There is no interference with expiratory valve function in the event of scavenging failure.

Drug analysis by direct liquid introduction micro liquid chromatography mass spectrometry.

The analytical capabilities of a micro high performance liquid chromatograph interfaced to an unchanged quadrupole mass spectrometer are presented. Continuous monitoring of the total micro liquid chromatographic effluent allows full scan chemical ionization mass spectra of from one to five nanograms of drugs and their metabolites to be recorded. The interface is a simple, inexpensive device which can be assembled from commercially available components. An eight microliter per minute flow rate of the micro liquid chromatographic eluant allows separation and identification of biologically important substances not amenable to gas chromatography mass spectrometry techniques. The sensitivity of micro liquid chromatography mass spectrometry performed as described is comparable with gas chromatography mass spectrometry and is achieved by introducing the total micro liquid chromatographic effluent into the chemical ionization ion source of the mass spectrometer. Selected ion monitoring provides 20 pg detection limits of phenothiazine tranquilizers injected on column.

Gas Flow Control Employing Temperature and Pressure Compensation

Two passive gas flow controllers are presented which provide compensation for variations in ambient temperature and supply pressure. One technique, which provides first-order error compensation, utilizes a choked orifice having its area linearily varied in proportion to a diaphragm deflection. Compensation is achieved by applying upstream pressure to one side of the diaphragm, and by applying a trapped gas pressure proportional to absolute temperature on the other side of the diaphragm. General design relationships are presented, and a prototype unit constructed to control a minute flow rate of high-pressure oxygen is described. A second flow control technique is presented which provides the required nonlinear temperature compensation for flow supplied through a constant-area choked orifice. This is achieved by utilizing a compliant volume of trapped gas to generate a pressure proportional to the square root of absolute temperature. This pressure is used to control the pressure upstream of the choked orifice, thus providing constant flow.

Organization of Field Tests and Evaluation Of Tricone Bit Performance Using Statistical Analysis and Sonic Logs

Raynal, Jean C., SPE-AIME, Societe Nationals des Petroles d'Aquitaine Gstalder, Serge A., Societe Nationale des Petroles d'Aquitaine Sagot, Andre M., Societe Nationale des Petroles d'Aquitaine Muckleroy, J.A.,* Amoco Production Co. The scatter of data in oilfield drilling makes evaluation of results using different bits highly uncertain. Conventional statistical theory is here applied to samples of field results to clarify and quantify evaluation, and recommendations are presented for organizing drillsite tests. Introduction The original text of this paper, which far exceeded the SPE's allowable length, has been condensed by the translator, using American statistical terms and drilling nomenclature. The complete original English text is on file with the SPE. For space reasons, it was necessary to omit the extensive mathematical and statistical development of the original; instead, references are given to standard textbooks where the basis of this development may be found. Although the statistical approach discussed here has been widely employed in agriculture, medicine, pharmacology, chemical analysis, pilot plant operation, and other fields in which tests are made on samples of a product or on changes produced by a cause, this approach of making statistical tests on pairs of experimental results on bits seems to have been largely neglected in drilling. Statement of the Problem Definition of the Problem When in drilling a well a technique or a tool is changed, it is often very difficult afterwards to answer the essential question: Did the change improve the result, or make it worse? Drilling results may be essentially shown in three ways:as footage drilled per hour;as footage drilled per bit; andas the cost per foot drilled, which incorporates the preceding two and is the most important result. The difficulties in judging these results are many and varied, but they always manifest themselves in a loss of time and so of money. If we wish the drilling tests to be proved absolutely, they must be repeated many times; if, on the other hand, we jump to a hasty conclusion, the result can be a bad decision. Either route is costly. Analysis of the Problem There are many variables in drilling, of which the most important are the following: Weight on bit (W) Diameter of bit (D) Type of bitWear on bit when pulled Revolutions per minute (rpm) Flow rate of drilling fluid (Q) Nature and properties of drilling fluid Pressure difference across rock surface ( p) Depth Rock properties Most of these are poorly measured. For the same drilling rig, drilling the same well, it is relatively easy to maintain constant values of W, rpm, and Q. JPT P. 506