Uncertainty Estimation of Biomedical Oximeters: Proposal for an Experimental Test-Bench

Author(s):  
Paolo Marchionni ◽  
Stefano Nobile ◽  
Virgilio Carnielli ◽  
Lorenzo Scalise

Abstract Paramagnetic oximeters are frequently used in clinical practice to measure and titrate the fraction of inspired oxygen (FiO2) administered to a hypoxic patient. Newborns are prone to several diseases leading to hypoxia but also to oxidative damage, therefore a precise measurement of administered oxygen is of paramount importance. In this study, we evaluated and compared the performance of four commonly used gas analyzers at a Neonatal Unit. A paramagnetic gas analyzer was considered the standard for reference. Gas mixing performed by blenders was also evaluated. We first assessed the stability and composition of O2 and medical air. A settling time study was conducted to estimate steady state. Results show how tested blenders underestimated the real measures when FiO2 was <50% and overestimated them when FiO2 =50%. In all the tested oximeters the FiO2 was underestimated by 1.18%, but the overall agreement with the gold standard was very good.

ABOUTOPEN ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 21-23
Author(s):  
Raffaele Di Fenza ◽  
Hedwige Gay ◽  
Martina Favarato ◽  
Isabella Fontana ◽  
Roberto Fumagalli

In severe acute respiratory distress syndrome (ARDS), characterized by the ratio of arterial partial pressure of oxygen over fraction of inspired oxygen (P/F) less than 150 mm Hg, pronation cycles are the only intervention that showed improved survival, in combination with protective ventilation. The physiological advantages of performing pronation cycles, such as the improvement of oxygenation, better tidal volume distribution with increased involvement of dorsal regions, and easier drainage of secretions, overcome the possible complications, that is, endotracheal tube occlusion or misplacement, pressure ulcers, and brachial plexus injury. However, the incidence of complications is dramatically lower in intensive care units with expertise, adopting prone positioning in daily practice. In this video we are proposing step by step an easy and ergonomic technique to perform pronation maneuvers in patients with severe ARDS. Recent literature suggests that a high percentage of these patients are treated without undergoing pronation cycles. The main purpose of this video is to help increase the number of intensive care units worldwide commonly performing pronation cycles in patients that have indications to be pronated, in order to decrease healthcare burden and costs directly caused by ARDS. Proper intensive care unit staff training is fundamental in minimizing the risks associated with the maneuver for both patients and operators; and diffusion of a safe technique encouraging the operators is the second main purpose of this video.


2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Andrew G. Weber ◽  
Alice S. Chau ◽  
Mikala Egeblad ◽  
Betsy J. Barnes ◽  
Tobias Janowitz

Abstract Background Mechanically ventilated patients with COVID-19 have a mortality of 24–53%, in part due to distal mucopurulent secretions interfering with ventilation. DNA from neutrophil extracellular traps (NETs) contribute to the viscosity of mucopurulent secretions and NETs are found in the serum of COVID-19 patients. Dornase alfa is recombinant human DNase 1 and is used to digest DNA in mucoid sputum. Here, we report a single-center case series where dornase alfa was co-administered with albuterol through an in-line nebulizer system. Methods Demographic and clinical data were collected from the electronic medical records of five mechanically ventilated patients with COVID-19—including three requiring veno-venous extracorporeal membrane oxygenation—treated with nebulized in-line endotracheal dornase alfa and albuterol, between March 31 and April 24, 2020. Data on tolerability and response were analyzed. Results The fraction of inspired oxygen requirements was reduced for all five patients after initiating dornase alfa administration. All patients were successfully extubated, discharged from hospital and remain alive. No drug-associated toxicities were identified. Conclusions Results suggest that dornase alfa will be well-tolerated by patients with severe COVID-19. Clinical trials are required to formally test the dosing, safety, and efficacy of dornase alfa in COVID-19, and several have been recently registered.


1973 ◽  
Vol 19 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
P A Drinker ◽  
D C Noonan ◽  
N Ramanaiah ◽  
J R Tole

Abstract Two different blood-gas analyzers were tested to determine the effects on blood pH measurement of changing the reference bridge solution from saturated KCl to normal saline (0.16 mol of NaCl per liter). This change, which necessitated the preparation of modified buffers equimolal in NaCl with respect to blood, virtually eliminated salt depletion of the bridge solution and improved the stability of the liquid-junction potential between the bridge solution and the sample. The instruments we used were the Corning 165 pH Blood Gas Analyzer and the Radiometer E5021 pH Electrode with PHM72 Acid Base Analyzer. Comparison of results on clinical blood samples indicates that performance with the modified bufferbridge system is the same as that obtained with the conventional scheme. Analytical performances of the Corning and Radiometer instruments for PO2 and PCO2, as well as for pH, were comparable.


2013 ◽  
Vol 392 ◽  
pp. 725-729 ◽  
Author(s):  
Rafael José Gomes de Oliveira ◽  
Mauro Hugo Mathias

The application of the HFRT (High-Frequency Resonance Technique), a demodulation based technique, is a technique for evaluation the condition of bearings and other components in rotating machinery. Another technique MED (Minimum Entropy Deconvolution) has been the subject of recent developments for application in condition monitoring of gear trains and roller bearings. This article demonstrates the effectiveness of the combined application of the MED technique with HFRT in order to enhance the capacity of HFRT to identify the characteristic fault frequencies of damaged bearings by increasing the signal impulsivity. All tests were done using data collected from an experimental test bench in laboratory. The Kurtosis value is used as an indicator of effectiveness of the combined technique and the results shown an increase of five times the original kurtosis value with the application of MED filter together with the HFRT.


2021 ◽  
Vol 70 (1) ◽  
pp. 1-36
Author(s):  
Toni Richter

Abstract Since the financial crisis of 2008 and intensified during the corona crisis, the interdependence between the stability of the financial systems and the prevailing degree of competition (DC) has been the subject of scientific and economic policy discourse on fragmented markets and „too-big-to-fail“ banks. In theory and empiricism, two fundamentally contrary causal concepts are opposed, the elementary basis of which is the precise measurement of the DC: Competition-stability- versus Fragility-Hypothesis. Based on the recent state of research, it can be shown that alternative DC-Measurements consistently show significantly different competitive conditions and in consequence the evidence for or against a stability-enhancing competitive effect seems to be predetermined by the chosen DC-Measurement.


Author(s):  
Dimitrios D. Ntakoulas ◽  
Ioannis N. Pasias ◽  
Apostolos Oikonomou ◽  
Pantelis Mpourazanis ◽  
Marios-Ilias Giannelos ◽  
...  

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881536 ◽  
Author(s):  
Yong Zhou ◽  
Xiaogang Zhou

The reliable and repeatable experimental ground testing of aircraft actuator is an essential phase before flight testing. It is not an easy task to simulate the alternating aerodynamic forces on actuators reasonably and accurately in a laboratory. In this article, an experimental test bench is designed to simulate the aerodynamic forces by a hydraulic actuator, which replicates the operating conditions that the actuator will encounter in service. In order to improve the force control performance, a feed-forward compensator and a fuzzy proportional–integral–derivative controller are designed. Both simulation and experimental results show that the designed method can improve the control performance.


Sign in / Sign up

Export Citation Format

Share Document