scholarly journals Another use for an oxygen analyser

Anaesthesia ◽  
1984 ◽  
Vol 39 (10) ◽  
pp. 1038-1039
Author(s):  
P.A. Ritchie
Keyword(s):  
1973 ◽  
Vol 45 (12) ◽  
pp. 1191-1197 ◽  
Author(s):  
C.M. CONWAY ◽  
J.M. LEIGH ◽  
M.J. LINDOP ◽  
D.A. WEBB

Heart ◽  
1966 ◽  
Vol 28 (6) ◽  
pp. 776-779 ◽  
Author(s):  
S Barold ◽  
F Burkart ◽  
E Sowton

Anaesthesia ◽  
1984 ◽  
Vol 39 (4) ◽  
pp. 380-381 ◽  
Author(s):  
J.K. Moore ◽  
R. Railton
Keyword(s):  

Author(s):  
Patrick Magee ◽  
Mark Tooley

The pulse oximeter is a device for non-invasive, continuous measurement of oxygen saturation. As such it is arguably one of the most important intraoperative monitors at the disposal of anaesthetists, and efforts are being made to make pulse oximeters available at all operating locations throughout the world [Walker et al. 2009]. Although the device measures oxygen saturation of arterial blood, which is the physiological end point of interest, it is not a replacement for monitoring all the events which may lead to hypoxaemia; in other words it does not replace an oxygen analyser at the common gas outlet of the anaesthetic machine. Depending on the site of the probe, usually ear lobe or finger, there is a variable delay between the onset of a causative hypoxaemic event and detection of hypoxaemia by the pulse oximeter, the delay being longer the more peripherally placed is the probe. Appropriate size and design of the probe for accuracy and safety in children is important [Howell et al. 1993] and finger probes are more accurate but slower to respond than ear probes [Webb et al. 1991]. Forehead reflectance probes have been used with good results [Casati et al. 2007]. It is also true that the human eye is notoriously bad at detecting cyanosis in the range of saturations 81–85%. For additional information on Monitoring Principles see Chapter 11. It is clear, however, that in a hierarchy of monitors for anaesthesia, the pulse oximeter is indispensable. A pulse oximeter uses two separate technologies: one is plethysmography, where reproduction of the pulsatile waveform takes place; the other is spectroscopy, where absorption of light of specific wavelengths by body tissues occurs and is analysed. The spectroscopic aspects depend on the laws of Beer and Lambert, which can be combined to state that the amount of light absorbed by a substance is proportional to the thickness of the substance sample (the path length of the light) and the concentration of the substance.


1975 ◽  
Vol 47 (10) ◽  
pp. 1118
Author(s):  
J.G. BRADLEY ◽  
F. MEADE ◽  
J.B. OWEN-THOMAS
Keyword(s):  

Thorax ◽  
2020 ◽  
Vol 75 (9) ◽  
pp. 805-807 ◽  
Author(s):  
Rémi Coudroy ◽  
Jean-Pierre Frat ◽  
Christophe Girault ◽  
Arnaud W Thille

Severity of hypoxaemia can be assessed using the partial pressure of arterial oxygen to fraction of inspired oxygen ratio (FiO2). However, in patients breathing through non-rebreather reservoir bag oxygen mask, accuracy of bedside FiO2 estimation methods remains to be tested. In a post-hoc analysis of a multicentre clinical trial, three FiO2 estimation methods were compared with FiO2 measured with a portable oxygen analyser introduced in the oxygen mask. Among 262 patients analysed, mean (SD) measured FiO2 was 65% (13). The 3%-formula (21% + oxygen flow rate in L/min × 3) was the most accurate method to estimate FiO2. Other methods overestimated FiO2 and hypoxaemia severity, so they should be avoided.


2021 ◽  
Vol 70 ◽  
pp. 151-173
Author(s):  
Robin Wootton

Charles Ellington graduated at Duke University, North Carolina, and came to Cambridge in 1973 to work for a PhD on insect flight dynamics. He developed novel methodology and software for the kinematic analysis of freely hovering insects and applied them to his own high-speed films of a range of species. He identified five new non-steady-state mechanisms for lift generation, was the first to develop a vortex theory for flapping flight and developed and extended the use of morphometric parameters in calculating the forces and power requirements of flight. He remained in Cambridge, married a colleague, joined the staff of the Department of Zoology, became a fellow of Downing College and continued to work on insect aerodynamics and energetics, publishing on flight muscle efficiency, the factors limiting flight performance and the aerodynamic implications of the origin of insect flight. Building a closed-circuit wind tunnel connected with a sensitive oxygen analyser, he studied with colleagues how the aerodynamics and metabolic power input of bumblebees vary with flight speed, challenging the orthodox theory that this should follow a U-shaped curve. Outstanding among later research was the discovery that hawkmoths, and by implication many other insects, gain high levels of lift by generating a vortex above the leading edge, stabilized by spiralling out along the span—a major focus of animal flight research ever since. His many administrative roles included editorship of theJournal of Experimental Biology. He became a British citizen in 1995, was elected FRS in 1998 and to a chair of animal mechanics in 1999. Awards include the Scientific Medal of the Zoological Society and the University of Cambridge Pilkington Prize for teaching excellence. He was diabetic throughout his adult life, and suffered progressive ill health following a heart attack in 1996. He took early retirement in 2010, lived quietly with his wife and two sons at home near Newmarket, and died in July 2019.


2020 ◽  
Vol 12 (1) ◽  
pp. 41-50
Author(s):  
I. Ethem Hindistan ◽  
Emel Cetin Ozdogan ◽  
Gürkan Bilgin ◽  
Omer Halil Colak ◽  
Y. Gul Ozkaya

SummaryStudy aim: Several sprint interval training applications with different slope angles in the literature mostly focused on sprint running time and kinematic and dynamic properties of running. There is a lack of comparative studies investigating aerobic and anaerobic power. Therefore, this study aimed to examine the effects of sprint interval training on sloping surfaces on anaerobic and aerobic power.Material and methods: A total of 34 male recreationally active men aged 20.26 ± 1.68 years and having a BMI of 21.77 ± 1.74 were assigned to one of the five groups as control (CON), uphill training (EXP1), downhill training (EXP2), uphill + downhill training (EXP3) and horizontal running training (EXP4) groups. Gradually increased sprint interval training was performed on horizontal and sloping surfaces with an angle of 4°. The training period continued for three days a week for eight weeks. The initial and the final aerobic power was measured by an oxygen analyser and anaerobic power was calculated from the results of the Margaria-Kalamen staircase test.Results: Following the training programme, an increase in aerobic power was found in all training groups (EXP1 = 20.79%, EXP2 = 14.95%, EXP3 = 26.85%, p < 0.01) and EXP4 = 20.46%) (p < 0.05) in comparison with the CON group (0.12%), but there were no differences among the training groups. However, significant increases in anaerobic power were found in uphill training (4.91%) and uphill + downhill training (8.35%) groups (p < 0.05).Conclusion: This study showed that all sprint interval studies on horizontal and sloping surfaces have a positive effect on aerobic power, and uphill and combined training are the most effective methods for the improvement of anaerobic power.


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