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American Journal of Respiratory and... Jan 2024Since publication of the 2012 Berlin definition of acute respiratory distress syndrome (ARDS), several developments have supported the need for an expansion of the...
Since publication of the 2012 Berlin definition of acute respiratory distress syndrome (ARDS), several developments have supported the need for an expansion of the definition, including the use of high-flow nasal oxygen, the expansion of the use of pulse oximetry in place of arterial blood gases, the use of ultrasound for chest imaging, and the need for applicability in resource-limited settings. A consensus conference of 32 critical care ARDS experts was convened, had six virtual meetings (June 2021 to March 2022), and subsequently obtained input from members of several critical care societies. The goal was to develop a definition that would ) identify patients with the currently accepted conceptual framework for ARDS, ) facilitate rapid ARDS diagnosis for clinical care and research, ) be applicable in resource-limited settings, ) be useful for testing specific therapies, and ) be practical for communication to patients and caregivers. The committee made four main recommendations: ) include high-flow nasal oxygen with a minimum flow rate of ⩾30 L/min; ) use Pa:Fi ⩽ 300 mm Hg or oxygen saturation as measured by pulse oximetry Sp:Fi ⩽ 315 (if oxygen saturation as measured by pulse oximetry is ⩽97%) to identify hypoxemia; ) retain bilateral opacities for imaging criteria but add ultrasound as an imaging modality, especially in resource-limited areas; and ) in resource-limited settings, do not require positive end-expiratory pressure, oxygen flow rate, or specific respiratory support devices. We propose a new global definition of ARDS that builds on the Berlin definition. The recommendations also identify areas for future research, including the need for prospective assessments of the feasibility, reliability, and prognostic validity of the proposed global definition.
Topics: Humans; Prospective Studies; Reproducibility of Results; Respiratory Distress Syndrome; Oximetry; Oxygen
PubMed: 37487152
DOI: 10.1164/rccm.202303-0558WS -
Indian Journal of Pediatrics Jul 2023Childhood pneumonia is still a significant clinical and public health problem. India contributes the highest number of deaths due to pneumonia, accounts for about 20% of... (Review)
Review
Childhood pneumonia is still a significant clinical and public health problem. India contributes the highest number of deaths due to pneumonia, accounts for about 20% of global mortality among under five children. Various etiologic agents including bacteria, viruses and atypical organism are responsible for childhood pneumonia. Recent studies suggest that viruses are one of the major causes of childhood pneumonia. Among viruses, respiratory syncytial virus has got great attention and several recent studies are reporting it as an important organism for pneumonia. Lack of exclusive breast feeding during first six months, improper timing of start and content of complimentary feeding, anemia, undernutrition, indoor pollution due to tobacco smoking and use of coal and wood for cooking food and lack of vaccinations are important risk factors. X-ray chest is not routinely performed to diagnose pneumonia while use of lung ultrasound is increasing to detect consolidation, pleural effusion, pneumothorax and pulmonary edema (interstitial syndrome). Role of C-reactive protein (CRP) and procalcitonin is similar, to differentiate between viral and bacterial pneumonia, however duration of antibiotics is better guided by procalcitonin. Newer biomarkers like IL-6, presepsin and triggering receptor expressed on myeloid cells 1 are needed to be evaluated for their use in children. Hypoxia is significantly associated with childhood pneumonia. Therefore, use of pulse oximetry should be encouraged for early detection and prompt treatment of hypoxia to prevent adverse outcomes. Among the available tools for risk of mortality assessment in children due to pneumonia, PREPARE score is the best but external validation will be needed.
Topics: Child; Female; Humans; Infant; Procalcitonin; Pneumonia; Pneumonia, Bacterial; Lung; C-Reactive Protein; Hypoxia; Peptide Fragments; Lipopolysaccharide Receptors
PubMed: 37204597
DOI: 10.1007/s12098-023-04628-3 -
American Journal of Respiratory and... Oct 2023Supplemental oxygen is widely administered to ICU patients, but appropriate oxygenation targets remain unclear. This study aimed to determine whether a low-oxygenation... (Randomized Controlled Trial)
Randomized Controlled Trial
Supplemental oxygen is widely administered to ICU patients, but appropriate oxygenation targets remain unclear. This study aimed to determine whether a low-oxygenation strategy would lower 28-day mortality compared with a high-oxygenation strategy. This randomized multicenter trial included mechanically ventilated ICU patients with an expected ventilation duration of at least 24 hours. Patients were randomized 1:1 to a low-oxygenation (Pa, 55-80 mm Hg; or oxygen saturation as measured by pulse oximetry, 91-94%) or high-oxygenation (Pa, 110-150 mm Hg; or oxygen saturation as measured by pulse oximetry, 96-100%) target until ICU discharge or 28 days after randomization, whichever came first. The primary outcome was 28-day mortality. The study was stopped prematurely because of the COVID-19 pandemic when 664 of the planned 1,512 patients were included. Between November 2018 and November 2021, a total of 664 patients were included in the trial: 335 in the low-oxygenation group and 329 in the high-oxygenation group. The median achieved Pa was 75 mm Hg (interquartile range, 70-84) and 115 mm Hg (interquartile range, 100-129) in the low- and high-oxygenation groups, respectively. At Day 28, 129 (38.5%) and 114 (34.7%) patients had died in the low- and high-oxygenation groups, respectively (risk ratio, 1.11; 95% confidence interval, 0.9-1.4; = 0.30). At least one serious adverse event was reported in 12 (3.6%) and 17 (5.2%) patients in the low- and high-oxygenation groups, respectively. Among mechanically ventilated ICU patients with an expected mechanical ventilation duration of at least 24 hours, using a low-oxygenation strategy did not result in a reduction of 28-day mortality compared with a high-oxygenation strategy. Clinical trial registered with the National Trial Register and the International Clinical Trials Registry Platform (NTR7376).
Topics: Humans; Pandemics; COVID-19; Critical Care; Oximetry; Intensive Care Units; Respiration, Artificial
PubMed: 37552556
DOI: 10.1164/rccm.202303-0560OC -
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 -
NeuroImage Aug 2023This article provides an overview of MRI methods exploiting magnetic susceptibility properties of blood to assess cerebral oxygen metabolism, including the tissue oxygen... (Review)
Review
This article provides an overview of MRI methods exploiting magnetic susceptibility properties of blood to assess cerebral oxygen metabolism, including the tissue oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO). The first section is devoted to describing blood magnetic susceptibility and its effect on the MRI signal. Blood circulating in the vasculature can have diamagnetic (oxyhemoglobin) or paramagnetic properties (deoxyhemoglobin). The overall balance between oxygenated and deoxygenated hemoglobin determines the induced magnetic field which, in turn, modulates the transverse relaxation decay of the MRI signal via additional phase accumulation. The following sections of this review then illustrate the principles underpinning susceptibility-based techniques for quantifying OEF and CMRO. Here, it is detailed whether these techniques provide global (OxFlow) or local (Quantitative Susceptibility Mapping - QSM, calibrated BOLD - cBOLD, quantitative BOLD - qBOLD, QSM+qBOLD) measurements of OEF or CMRO, and what signal components (magnitude or phase) and tissue pools they consider (intravascular or extravascular). Validations studies and potential limitations of each method are also described. The latter include (but are not limited to) challenges in the experimental setup, the accuracy of signal modeling, and assumptions on the measured signal. The last section outlines the clinical uses of these techniques in healthy aging and neurodegenerative diseases and contextualizes these reports relative to results from gold-standard PET.
Topics: Humans; Brain; Magnetic Resonance Imaging; Oxygen; Oxygen Consumption; Cerebrovascular Circulation
PubMed: 37230206
DOI: 10.1016/j.neuroimage.2023.120189