scholarly journals A SIMPLE AND RELIABLE WARNING DEVICE FOR FAILING OXYGEN PRESSURE

1974 ◽  
Vol 46 (4) ◽  
pp. 323 ◽  
Author(s):  
J.R. RITCHIE
VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 355-362 ◽  
Author(s):  
Marie Urban ◽  
Alban Fouasson-Chailloux ◽  
Isabelle Signolet ◽  
Christophe Colas Ribas ◽  
Mathieu Feuilloy ◽  
...  

Abstract. Summary: Background: We aimed at estimating the agreement between the Medicap® (photo-optical) and Radiometer® (electro-chemical) sensors during exercise transcutaneous oxygen pressure (tcpO2) tests. Our hypothesis was that although absolute starting values (tcpO2rest: mean over 2 minutes) might be different, tcpO2-changes over time and the minimal value of the decrease from rest of oxygen pressure (DROPmin) results at exercise shall be concordant between the two systems. Patients and methods: Forty seven patients with arterial claudication (65 + / - 7 years) performed a treadmill test with 5 probes each of the electro-chemical and photo-optical devices simultaneously, one of each system on the chest, on each buttock and on each calf. Results: Seventeen Medicap® probes disconnected during the tests. tcpO2rest and DROPmin values were higher with Medicap® than with Radiometer®, by 13.7 + / - 17.1 mm Hg and 3.4 + / - 11.7 mm Hg, respectively. Despite the differences in absolute starting values, changes over time were similar between the two systems. The concordance between the two systems was approximately 70 % for classification of test results from DROPmin. Conclusions: Photo-optical sensors are promising alternatives to electro-chemical sensors for exercise oximetry, provided that miniaturisation and weight reduction of the new sensors are possible.


2006 ◽  
Author(s):  
Melinda McElheny ◽  
Myra Blanco ◽  
Jonathan M. Hankey
Keyword(s):  

1986 ◽  
Vol 51 (8) ◽  
pp. 1795-1801
Author(s):  
Hana Hájková ◽  
Zdeněk Pavlíček ◽  
Vítěz Kalous

The time profile of changes in the oxygen saturation curves of human hemoglobin in the presence of benzene was investigated. The partial oxygen pressure p50, necessary for a half saturation, decreases during the first 3.5 h of interaction of hemoglobin with benzene and did not change afterwards. The character of changes in Hill's coefficient was similar. The oxygen saturation was modeled both for hemoglobin alone and, using MWC as a model of allosteric interaction, also for hemoglobin and benzene in a computer.


2021 ◽  
Vol 22 (3) ◽  
pp. 1122
Author(s):  
Mario Forcione ◽  
Mario Ganau ◽  
Lara Prisco ◽  
Antonio Maria Chiarelli ◽  
Andrea Bellelli ◽  
...  

The brain tissue partial oxygen pressure (PbtO2) and near-infrared spectroscopy (NIRS) neuromonitoring are frequently compared in the management of acute moderate and severe traumatic brain injury patients; however, the relationship between their respective output parameters flows from the complex pathogenesis of tissue respiration after brain trauma. NIRS neuromonitoring overcomes certain limitations related to the heterogeneity of the pathology across the brain that cannot be adequately addressed by local-sample invasive neuromonitoring (e.g., PbtO2 neuromonitoring, microdialysis), and it allows clinicians to assess parameters that cannot otherwise be scanned. The anatomical co-registration of an NIRS signal with axial imaging (e.g., computerized tomography scan) enhances the optical signal, which can be changed by the anatomy of the lesions and the significance of the radiological assessment. These arguments led us to conclude that rather than aiming to substitute PbtO2 with tissue saturation, multiple types of NIRS should be included via multimodal systemic- and neuro-monitoring, whose values then are incorporated into biosignatures linked to patient status and prognosis. Discussion on the abnormalities in tissue respiration due to brain trauma and how they affect the PbtO2 and NIRS neuromonitoring is given.


2021 ◽  
pp. 413174
Author(s):  
Yuxin Shi ◽  
Pengwei Zhai ◽  
Lixiang Meng ◽  
Zongyin Huang ◽  
Guoqiang Li

2016 ◽  
Vol 29 (6) ◽  
pp. 1483-1489 ◽  
Author(s):  
S. Aghabagheri ◽  
M. R. Mohammadizadeh ◽  
P. Kameli ◽  
H. Salamati

1993 ◽  
Vol 74 (2) ◽  
pp. 580-589 ◽  
Author(s):  
D. F. Wilson ◽  
S. Gomi ◽  
A. Pastuszko ◽  
J. H. Greenberg

Oxygen-dependent quenching of phosphorescence provides an extraordinarily powerful method for examining the effects of ischemia/hypoxia on the cortex of the brain. Video camera technology has permitted imaging, through a window in the skull, of the phosphorescence of an oxygen probe, Pd meso-tetra-(4-carboxyphenyl)-porphine, bound to albumin in the blood of anesthetized animals. Images of the phosphorescence taken at different times after the flash of excitation light were used to generate high-resolution two-dimensional maps of the oxygen pressure. These maps show that cortical oxygenation is spatially heterogeneous and that there is dynamic time-dependent modulation of regional oxygen pressures. When the middle cerebral artery was occluded, the region for which it supplied blood became hypoxic, the severity of the hypoxia varying among animals. Release after 60 min of occlusion resulted in a rapid rise of the oxygen pressure to above-normal levels followed by onset of a delayed period of hypoxia. This period is characterized by generally low tissue oxygen pressures with local regions of more severe hypoxia. The delayed period of hypoxia appears to result from damage to the microvasculature, and this microvascular damage is proposed to be an important determinant of the extent of irreversible brain damage.


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