scholarly journals Constancy of Air-Oxygen Mixtures in Intensive Care

1989 ◽  
Vol 17 (1) ◽  
pp. 78-82
Author(s):  
P. A. Johnson ◽  
A. K. Outhred ◽  
R. F. Raper ◽  
M. McD. Fisher
Keyword(s):  
Oxygen Delivery ◽  
Open Circuit ◽  
High Flow ◽  
Low Flow ◽  
Pure Oxygen ◽  
Intermittent Flow ◽  
Considerable Impact ◽  
Clinically Significant ◽  
The Stability ◽  
Oxygen Concentrations

The performance of ten high-flow Bird blenders (3M Company) was assessed to ascertain the stability of the oxygen delivery both over time and within a single respiratory cycle. Blended oxygen concentrations were assessed for both continuous low flow and for intermittent flow with variable tidal volumes as is seen with mechanical ventilation. Studies were repeated after the addition of a high flow bleed from the blender via a T-piece. We observed clinically significant variations in the oxygen concentrations delivered by several blenders when the relationship between air and oxygen supply pressures varied. This variability was greatest when the air and oxygen pressures were nearly equal. When the line pressures were stable, mixed oxygen concentrations were constant but variations in oxygen delivery were found within individual breath cycles. This could be explained by postulating that at the initiation of flow from the blender a small pocket of unblended gas (pure air or pure oxygen) was issued by the blender before the balancing mechanism stabilised to deliver the desired oxygen concentration. This variability of oxygen delivery may have considerable impact on the measurement of oxygen consumption using the open circuit technique. The addition of a high flow bleed completely ablated this blender-derived variation in oxygen delivery.

scholarly journals Randomised controlled trial to assess the effectiveness of apnoeic oxygenation in adults using low-flow or high-flow nasal cannula with head side elevation versus usual care to prevent desaturation during endotracheal intubation in the emergency department (ApOxED): study protocol

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e037964
Author(s):  
Shahan Waheed ◽  
Nazir Najeeb Kapadia ◽  
Muhammad Faisal Khan ◽  
Salima Mansoor Kerai ◽  
Ahmed Raheem ◽  
...  
Keyword(s):  
Endotracheal Intubation ◽  
Direct Laryngoscopy ◽  
Oxygen Delivery ◽  
High Flow ◽  
Nasal Cannula ◽  
Low Flow ◽  
Usual Practice ◽  
High Flow Oxygen ◽  
Randomised Controlled ◽  
Apnoeic Oxygenation

IntroductionApnoeic oxygenation is a process of delivering continuous oxygen through nasal cannula during direct laryngoscopy. The oxygen that is delivered through these nasal cannulas is either low flow or high flow. Although the effectiveness of apnoeic oxygenation has been shown through systematic reviews and randomised controlled trials, a comparison of high-flow versus low-flow oxygen delivery has not been tested through a superiority study design. In this study we propose to assess the effectiveness of giving low-flow oxygen with head side elevation versus high-flow oxygen with head side elevation against the usual practice of care in which no oxygen is provided during direct laryngoscopy.Methods and analysisThis will be a three-arm study instituting a block randomisation technique with a sample size of 46 in each arm (see table 1). Due to the nature of the intervention, no blinding will be introduced. The primary outcomes will be lowest non-invasive oxygen saturation measurement during direct laryngoscopy and during the 2 min after the placement of the tube and the first pass success rate. The intervention constitutes head side elevation up to 30° for improving glottis visualisation together with low-flow or high-flow oxygen delivery through nasal cannula to increase safe apnoea time for participants undergoing endotracheal intubation. Primary analysis will be intention to treat.Ethics and disseminationThe study is approved by the Ethical Review Committee of Aga Khan University Hospital (2019-0726-2463). The project is an institution University Research Committee grant recipient 192 002ER-PK. The results of the study will be disseminated among participants, patient communities and healthcare professionals in the institution through seminars, presentations and emails. Further, the findings will be published in a highly accessed peer-reviewed medical journal and will be presented at both national and international conferences.Trial registration numberClinicalTrials.gov Registry (NCT04242537).

scholarly journals What Are High-Flow and Low-Flow Oxygen Delivery Systems?

Stroke ◽  
2005 ◽  
Vol 36 (10) ◽  
pp. 2066-2067 ◽  
Author(s):  
Ritesh Agarwal ◽  
Dheeraj Gupta
Keyword(s):  
Oxygen Delivery ◽  
Delivery Systems ◽  
High Flow ◽  
Low Flow

Using a high-flow nasal cannula provided superior results to low-flow oxygen delivery in moderate to severe bronchiolitis

2016 ◽  
Vol 105 (8) ◽  
pp. e368-e372 ◽  
Author(s):  
Gregorio P. Milani ◽  
Anna M. Plebani ◽  
Elisa Arturi ◽  
Danila Brusa ◽  
Susanna Esposito ◽  
...  
Keyword(s):  
Oxygen Delivery ◽  
High Flow ◽  
Nasal Cannula ◽  
Low Flow ◽  
High Flow Nasal Cannula

Experimental Study on the Speed Matching of Two Rotors for a Counter-Rotating Fan

2018 ◽  
Author(s):  
Zijian Ai ◽  
Guoliang Qin ◽  
Jingxiang Lin ◽  
Xuefei Chen
Keyword(s):  
Flow Rate ◽  
Pressure Rise ◽  
Stability Margin ◽  
Rapid Decrease ◽  
High Flow ◽  
High Flow Rate ◽  
Low Flow ◽  
The Stability ◽  
Equal Power ◽  
Low Flow Rate

A method for the speed matching of the second rotor (R2) with equal power for two rotors was proposed to avoid the overload of the second motor under low flow rate and the rapid decrease in pressure-rise and efficiency of R2 under high flow rate. The speed matching of two-stage rotors is proposed and analyzed to improve the stability margin of the counter-rotating fan (CRF). The fan performances during constant speed operating and during the speed matching operating are presented and discussed using experimental research. The results show that, the speed matching of R2 operating decreases the load of R2 under low flow rate and increases the pressure-rise and efficiency of R2 under high flow rate. Thus, the efficient working range and the blocking condition margin are increased. Reducing n1 and increasing n2 under low flow rate can regulate the position of unstable working line leftward without reducing the pressure-rise of the fan. Thus, the stability margin of the CRF is expanded.

scholarly journals Transportation of steam-water mixture during development of steam-water fields.

2018 ◽  
Vol 56 ◽  
pp. 01008 ◽  
Author(s):  
Alexander Shulyupin ◽  
Natalia Varlamova
Keyword(s):  
Hydraulic Resistance ◽  
High Flow ◽  
Low Flow ◽  
Water Mixture ◽  
Flow Rates ◽  
Foreign Experience ◽  
Scientific Principles ◽  
New Challenges ◽  
The Stability

The main problems of transporting the steam-water mixture revealed during steam-water fields development: pulsations of parameters at low flow rates and considerable hydraulic resistance at high flow rates. The domestic experience of the calculation of steam-water mixture pipelines, oriented to the dispersed-ring flow, is considered. Based on the analysis of domestic and foreign experience in the steam-water fields development, new challenges have been identified that make it urgent to develop scientific principles for the transport of steam-water mixture at low rates, taking into account modern concepts of the stability of steamwater flows.

scholarly journals Soil microbial inoculation during flood events shapes headwater stream microbial communities and diversity

2021 ◽  
Author(s):  
Florian Caillon ◽  
Katharina Besemer ◽  
Peter Peduzzi ◽  
Jakob Schelker
Keyword(s):  
Microbial Diversity ◽  
Bacterial Diversity ◽  
Soil Water ◽  
Headwater Streams ◽  
High Flow ◽  
Low Flow ◽  
Flood Events ◽  
Flow Conditions ◽  
Soil Microbial ◽  
Microbial Inoculation

AbstractFlood events are now recognized as potentially important occasions for the transfer of soil microbes to stream ecosystems. Yet, little is known about these “dynamic pulses of microbial life” for stream bacterial community composition (BCC) and diversity. In this study, we explored the potential alteration of stream BCC by soil inoculation during high flow events in six pre-alpine first order streams and the larger Oberer Seebach. During 1 year, we compared variations of BCC in soil water, stream water and in benthic biofilms at different flow conditions (low to intermediate flows versus high flow). Bacterial diversity was lowest in biofilms, followed by soils and highest in headwater streams and the Oberer Seebach. In headwater streams, bacterial diversity was significantly higher during high flow, as compared to low flow (Shannon diversity: 7.6 versus 7.9 at low versus high flow, respectively, p < 0.001). Approximately 70% of the bacterial operational taxonomic units (OTUs) from streams and stream biofilms were the same as in soil water, while in the latter one third of the OTUs were specific to high flow conditions. These soil high-flow OTUs were also found in streams and biofilms at other times of the year. These results demonstrate the relevance of floods in generating short and reoccurring inoculation events for flowing waters. Moreover, they show that soil microbial inoculation during high flow enhances microbial diversity and shapes fluvial BCC even during low flow. Hence, soil microbial inoculation during floods could act as a previously overlooked driver of microbial diversity in headwater streams.

Corrosion Rate Measurement by Hydrogen Effusion In Dynamic Aqueous Systems At Elevated Temperature and Pressure

CORROSION ◽  
1959 ◽  
Vol 15 (4) ◽  
pp. 29-32
Author(s):  
M. KRULFELD ◽  
M. C. BLOOM ◽  
R. E. SEEBOLD
Keyword(s):  
Elevated Temperature ◽  
Corrosion Rate ◽  
Flow Velocity ◽  
High Flow ◽  
Low Flow ◽  
Aqueous Systems ◽  
Effusion Rates ◽  
Temperature And Pressure ◽  
Effusion Method ◽  
Hydrogen Effusion

Abstract A method of applying the hydrogen effusion method to the measurement of corrosion rates in dynamic aqueous systems at elevated temperature and pressure is described. Data obtained in low carbon steel systems are presented, including (1) reproducibility obtained in measured hydrogen effusion rates at a flow velocity of 1 foot per second at a temperature of 600 F and 2000 psi, and (2) a quantitative comparison between the hydrogen effusion rates in static and in low flow velocity dynamic systems at this temperature and pressure. Some observations are included on corrosion rate measurements in a high flow velocity (30 feet per second) loop by the hydrogen effusion method. Implications of these measurements with regard to the comparison between high flow velocity corrosion and low flow velocity corrosion are mentioned and some data indicating high local sensitivity of the hydrogen effusion method are noted. Some possible difficulties involved in the method are pointed out. 2.3.4

Sign in / Sign up

Export Citation Format

Share Document