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Respiratory Care Jun 2017Noninvasive monitoring of oxygenation and ventilation is an essential part of pediatric respiratory care. Carbon dioxide, gas exchange monitoring, transcutaneous... (Review)
Review
Noninvasive monitoring of oxygenation and ventilation is an essential part of pediatric respiratory care. Carbon dioxide, gas exchange monitoring, transcutaneous monitoring, near-infrared spectroscopy, pulse oximetry, and electrical impedance tomography are examined. Although some of these technologies have been utilized for decades, incorporation into mechanical ventilators and recently developed methods may provide important clinical insights in a broader patient range. Less mature technologies (electrical impedance tomography and near-infrared spectroscopy) have been of particular interest, since they offer easy bedside application and potential for improved care of children with respiratory failure and other disorders. This article provides an overview of the principles of operation, a survey of recent and relevant literature, and important technological limitations and future research directions.
Topics: Blood Gas Monitoring, Transcutaneous; Child; Electric Impedance; Humans; Monitoring, Physiologic; Oximetry; Oxygen; Point-of-Care Testing; Respiratory Function Tests; Respiratory Insufficiency; Spectroscopy, Near-Infrared; Tomography
PubMed: 28546376
DOI: 10.4187/respcare.05243 -
Expert Review of Respiratory Medicine Aug 2018Overnight oximetry has been proposed as an accessible, simple, and reliable technique for obstructive sleep apnea syndrome (OSAS) diagnosis. From visual inspection to... (Review)
Review
Overnight oximetry has been proposed as an accessible, simple, and reliable technique for obstructive sleep apnea syndrome (OSAS) diagnosis. From visual inspection to advanced signal processing, several studies have demonstrated the usefulness of oximetry as a screening tool. However, there is still controversy regarding the general application of oximetry as a single screening methodology for OSAS. Areas covered: Currently, high-resolution portable devices combined with pattern recognition-based applications are able to achieve high performance in the detection of this disease. In this review, recent studies involving automated analysis of oximetry by means of advanced signal processing and machine learning algorithms are analyzed. Advantages and limitations are highlighted and novel research lines aimed at improving the screening ability of oximetry are proposed. Expert commentary: Oximetry is a cost-effective tool for OSAS screening in patients showing high pretest probability for the disease. Nevertheless, exhaustive analyses are still needed to further assess unattended oximetry monitoring as a single diagnostic test for sleep apnea, particularly in the pediatric population and in populations with significant comorbidities. In the following years, communication technologies and big data analyses will overcome current limitations of simplified sleep testing approaches, changing the detection and management of OSAS.
Topics: Algorithms; Cost-Benefit Analysis; Humans; Oximetry; Polysomnography; Sleep Apnea, Obstructive
PubMed: 29972344
DOI: 10.1080/17476348.2018.1495563 -
Nigerian Journal of Clinical Practice Nov 2023The physical examination is a key part of a continuum that extends from the history of the present illness to the therapeutic outcome. An understanding of the... (Review)
Review
The physical examination is a key part of a continuum that extends from the history of the present illness to the therapeutic outcome. An understanding of the pathophysiological mechanism behind a physical sign is essential for arriving at the correct diagnosis. Early detection of deteriorating physical/vital signs and their appropriate interpretation is thus the key to achieve correct and timely management. By definition, vital signs are "the signs of life that may be monitored or measured, namely pulse rate, respiratory rate, body temperature, and blood pressure." Vital signs are the simplest, cheapest and probably the most inexpensive information gathered bedside in outpatient or hospitalized patients. The pulse oximeter was introduced in the 1980s. It is an accurate and non-invasive method for the measurement of arterial hemoglobin oxygen saturation (SaO2). Pulse oximetry-based arterial oxygen saturation can be effectively used bedside in in-hospital and ambulatory patients with diagnosed or suspected lung disease. The present pandemic of COVID-19 should be considered as a wake-up call. Articles related to arterial oxygen saturation and its importance as a vital sign in patient care were searched online especially in PubMed. Available studies were studied in full length and data was extracted. Discussion: A. Clinical Utility of Oxygen Saturation Monitoring: There are many studies reporting the clinical applicability and usefulness of pulse oximetry in the early detection of hypoxemic events during intraoperative and postoperative periods. B. Role of clinical expertise accompanied by knowledge of physiology: A diagnostic sign is useful only if it is interpreted accurately and applied appropriately while evaluating a patient. The World Health Organisation also appreciates these facts and published "The WHO Pulse Oximetry Training Manual." Understanding the physiology behind and overcoming limitations of the diagnostic sign by clinical expertise is important. While using pulse oximetry, a clinician needs to keep in mind the sigmoidal nature of the oxygen-Hb dissociation curve. Considering these benefits of SaO2 measurement, there have been several references in the past to consider oxygen saturation as the fifth vital sign. In the present pandemic oxygen saturation i.e., SpO2 (arterial oxygen saturation) measured by pulse oxymeter, has been the single most important warning and prognostic sign be it for households, offices, street vendors, hospitals or governments. Measurement of trends of SaO2 added with respiratory rate will provide clinicians with a holistic overview of respiratory functions and multidimensional conditions associated with hypoxemia.
Topics: Humans; Heart Rate; Hypoxia; Oximetry; Oxygen; Oxygen Saturation
PubMed: 38044759
DOI: 10.4103/njcp.njcp_2026_21 -
The Canadian Veterinary Journal = La... Nov 2017Monitoring equipment has become reliable and affordable for use in general veterinary practice. This article provides a guide to technology, troubleshooting, and... (Review)
Review
Monitoring equipment has become reliable and affordable for use in general veterinary practice. This article provides a guide to technology, troubleshooting, and obtaining quality data using 4 non-invasive techniques that are commonly used in practice. Pulse oximetry estimates oxygen saturation of hemoglobin in arterial blood, capnography measures the carbon dioxide content of inspired and expired gas, and either Doppler shift detection or oscillometry can be used to measure blood pressure. These useful non-invasive techniques all rely on adequate perfusion of the tissues for optimum function.
Topics: Animals; Blood Pressure Determination; Capnography; Mammals; Monitoring, Intraoperative; Monitoring, Physiologic; Oximetry
PubMed: 29089659
DOI: No ID Found -
Journal of Ayub Medical College,... 2017Studies have shown maintaining good cerebral perfusion during Cardiac Surgeries is very important in terms of patient outcomes and reducing the hospital stay, which may... (Review)
Review
BACKGROUND
Studies have shown maintaining good cerebral perfusion during Cardiac Surgeries is very important in terms of patient outcomes and reducing the hospital stay, which may have its financial and clinical implications. The aim of this review study was to determine the effectiveness of Cerebral Oximetry (Transcranial Near-Infrared Spectroscopy-NIRS to monitor cerebral oxygenation) for Cardiac Surgery and to propose a possible concluding remark about its potential applications, overall clinical value and whether to keep using it or not.
METHODS
Medical database and archives including Pubmed, Embase, index medicus, index copernicus and Medline were searched. Different papers were looked upon and each had an argument, scientific evidence and background. Fifteen research papers were selected and brought under review after carefully consideration.
RESULTS
The papers were carefully reviewed and findings were given in favour of not using NIRS technique for Cerebral Oximetry in Cardiac Surgery.
CONCLUSIONS
This can rightly be concluded from this study that NIRS Cerebral Oximetry does not carry the clinical significance and relevance which was previously thought. The subject under observation needs further studies and research to evaluate the effectiveness of the Cerebral Oximetry Use for Cardiac Surgery.
Topics: Cardiac Surgical Procedures; Cerebrovascular Circulation; Heart Diseases; Humans; Monitoring, Physiologic; Oximetry; Spectroscopy, Near-Infrared
PubMed: 28718260
DOI: No ID Found -
Biomedizinische Technik. Biomedical... Oct 2018Pulse oximetry for arterial oxygenation monitoring and tissue oximetry for monitoring of cerebral oxygenation or muscle oxygenation are based on quantitative in vivo... (Review)
Review
Pulse oximetry for arterial oxygenation monitoring and tissue oximetry for monitoring of cerebral oxygenation or muscle oxygenation are based on quantitative in vivo diffuse optical spectroscopy. However, in both cases the information on absolute or relative concentration of human tissue constituents and especially on hemoglobin oxygenation can often not be retrieved by model-based analysis. An in vivo calibration against an accepted reference measurement can be a practical alternative. Pulse oximeters and most of commercial cerebral tissue oximeters rely on empirical calibration based on invasive controlled human desaturation studies. As invasive in vivo tests on healthy subjects are ethically disputable and should be limited to exceptional cases this calibration practice is unsatisfactory. We present the current status and problems of calibration and validation in pulse oximetry and cerebral tissue oximetry including the pros and cons of in vivo as well as in vitro methods. We emphasize various digital and physical phantom approaches and discuss the prospects of their application and possible further developments.
Topics: Calibration; Humans; Monitoring, Physiologic; Oximetry; Spectroscopy, Near-Infrared
PubMed: 29425103
DOI: 10.1515/bmt-2017-0116 -
Journal of Veterinary Emergency and... Sep 2018To review clinically relevant features of systemic oxygen delivery and consumption and the technique and use of venous oxygenation monitoring in human and veterinary... (Review)
Review
OBJECTIVE
To review clinically relevant features of systemic oxygen delivery and consumption and the technique and use of venous oxygenation monitoring in human and veterinary medicine.
DATA SOURCES
Veterinary and human peer-reviewed medical literature including scientific reviews, clinical and laboratory research articles, and authors' clinical research experience.
SUMMARY
Measurement of venous hemoglobin oxygen saturation (venous oxygenation) provides insight into the balance between oxygen supply and tissue demand. In people, measurement of venous oxygen saturation can reveal decompensation that is missed by physical examination and other routinely monitored parameters. Therefore, measurement of mixed or central venous oxygenation measurement may help guide therapy and predict outcome of critically ill patients. In dogs, low central venous oxygen saturation has been associated with impaired cardiopulmonary function and poor outcome in several small studies of experimental shock or severe clinical illness, suggesting that monitoring this variable may assist the treatment of severe illness in this species as well.
CONCLUSION
Venous oxygenation reflects systemic oxygenation status and can be used to guide treatment and estimate prognosis in critically ill patients. Measurement of venous oxygenation in veterinary patients is feasible and is a potentially valuable tool in the management of patients with severe disease. This review is intended to increase the understanding and awareness of the potential role of venous oxygen measurement in veterinary patients.
Topics: Animals; Critical Illness; Monitoring, Physiologic; Oximetry; Oxygen
PubMed: 30071148
DOI: 10.1111/vec.12749 -
Molecular Imaging and Biology Apr 2022Hypoxia is a key prognostic indicator in most solid tumors, as it is correlated to tumor angiogenesis, metastasis, recurrence, and response to therapy. Accurate... (Review)
Review
Hypoxia is a key prognostic indicator in most solid tumors, as it is correlated to tumor angiogenesis, metastasis, recurrence, and response to therapy. Accurate measurement and mapping of tumor oxygenation profile and changes upon intervention could facilitate disease progression assessment and assist in treatment planning. Currently, no gold standard exists for non-invasive spatiotemporal measurement of hypoxia. Magnetic resonance imaging (MRI) represents an attractive option as it is a clinically available and non-ionizing imaging modality. Specifically, perfluorocarbon (PFC) beacons can be externally introduced into the tumor tissue and the linear dependence of their spin-lattice relaxation rate (R1) on the local partial pressure of oxygen (pO) exploited for real-time tissue oxygenation monitoring in vivo. In this review, we will focus on early studies and recent developments of fluorine-19 MRI and spectroscopy (MRS) for evaluation of tumor oximetry and response to therapy.
Topics: Fluorine; Fluorocarbons; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Neoplasms; Oximetry; Oxygen; Prognosis
PubMed: 34708396
DOI: 10.1007/s11307-021-01648-3 -
Archives of Disease in Childhood.... Jun 2020A 5-year-old child presents to a paediatric clinic with their parents because of concerns about snoring, which is loud, every night and associated with respiratory... (Review)
Review
A 5-year-old child presents to a paediatric clinic with their parents because of concerns about snoring, which is loud, every night and associated with respiratory pauses. This has been present for 6 months. Can clinical evaluation diagnose sleep-disordered breathing in children or are further investigations required? Should further investigations include oximetry or polysomnography? If a polysomnogram is performed, how are the results interpreted? In this paper we describe the indications for polysomnography, outline the parameters measured and decode a clinical polysomnography report.
Topics: Adolescent; Child; Child, Preschool; Female; Humans; Male; Oximetry; Pediatrics; Polysomnography; Practice Guidelines as Topic; Sleep Apnea Syndromes; Snoring; Surveys and Questionnaires
PubMed: 31615846
DOI: 10.1136/archdischild-2018-316031 -
Magnetic Resonance Imaging Apr 2023The R relaxation rate of fat is a promising marker of tissue oxygenation. Existing techniques to map fat R in MR-oximetry offer limited spatial coverage, require long...
PURPOSE
The R relaxation rate of fat is a promising marker of tissue oxygenation. Existing techniques to map fat R in MR-oximetry offer limited spatial coverage, require long scan times, or pulse sequences that are not readily available on clinical scanners. This work addresses these limitations with a 3D voxel-wise fat R mapping technique for MR-oximetry based on a variable flip angle (VFA) approach at 3 T.
METHODS
Varying levels of dissolved oxygen (O) were generated in a phantom consisting of vials of safflower oil emulsion, used to approximate human fat. Joint voxel-wise mapping of fat and water R was performed with a two-compartment VFA model fitted to multi-echo gradient-echo magnitude data acquired at four flip angles, referred to as Fat DESPOT. Global R was also calculated. Variations of fat, water, and global R were investigated as a function of the partial pressure of O (pO). Inversion-prepared stimulated echo magnetic resonance spectroscopy was used as the reference technique for R measurements.
RESULTS
Fat R from Fat DESPOT was more sensitive than water R and global R to variations in pO, consistent with previous studies performed with different R mapping techniques. Fat R sensitivity to pO variations with Fat DESPOT (median O relaxivity r = 1.57× 10 s mmHg) was comparable to spectroscopy-based measurements for methylene, the main fat resonance (median r= 1.80 × 10 s mmHg).
CONCLUSION
Fat and water R can be measured on a voxel-wise basis using a two-component fit to multi-echo 3D VFA magnitude data in a clinically acceptable scan time. Fat and water R measured with Fat DESPOT were sensitive to variations in pO. These observations suggest an approach to 3D in vivo MR oximetry.
Topics: Humans; Oximetry; Oxygen; Magnetic Resonance Spectroscopy; Magnetic Resonance Imaging
PubMed: 36608912
DOI: 10.1016/j.mri.2022.12.023