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Respiratory Care Jun 2020Mechanical ventilation is an indispensable form of life support for patients undergoing general anesthesia or experiencing respiratory failure in the setting of critical... (Review)
Review
Mechanical ventilation is an indispensable form of life support for patients undergoing general anesthesia or experiencing respiratory failure in the setting of critical illness. These patients are at risk for a number of complications related to both their underlying disease states and the mechanical ventilation itself. Intensive monitoring is required to identify early signs of clinical worsening and to minimize the risk of iatrogenic harm. Pulse oximetry and capnography are used to ensure that appropriate oxygenation and ventilation are achieved and maintained. Assessments of driving pressure, transpulmonary pressure, and the pressure-volume loop are performed to ensure that adequate PEEP is applied and excess distending pressure is minimized. Finally, monitoring and frequent adjustment of airway cuff pressures is performed to minimize the risk of airway injury and ventilator-associated pneumonia. We will discuss monitoring during mechanical ventilation with a focus on the accuracy, ease of use, and effectiveness in preventing harm for each of these monitoring modalities.
Topics: Capnography; Humans; Monitoring, Physiologic; Oximetry; Respiration, Artificial; Respiratory Function Tests
PubMed: 32457174
DOI: 10.4187/respcare.07812 -
The Lancet. Respiratory Medicine Nov 2022The diagnosis of acute respiratory distress syndrome (ARDS) traditionally requires calculation of the ratio of partial pressure of arterial oxygen to fraction of... (Review)
Review
The diagnosis of acute respiratory distress syndrome (ARDS) traditionally requires calculation of the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO/FiO) using arterial blood, which can be costly and is not possible in many resource-limited settings. By contrast, pulse oximetry is continuously available, accurate, inexpensive, and non-invasive. Pulse oximetry-based indices, such as the ratio of pulse-oximetric oxygen saturation to FiO (SpO/FiO), have been validated in clinical studies for the diagnosis and risk stratification of patients with ARDS. Limitations of the SpO/FiO ratio include reduced accuracy in poor perfusion states or above oxygen saturations of 97%, and the potential for reduced accuracy in patients with darker skin pigmentation. Application of pulse oximetry to the diagnosis and management of ARDS, including formal adoption of the SpO/FiO ratio as an alternative to PaO/FiO to meet the diagnostic criterion for hypoxaemia in ARDS, could facilitate increased and earlier recognition of ARDS worldwide to advance both clinical practice and research.
Topics: Humans; Oximetry; Respiratory Distress Syndrome; Oxygen
PubMed: 36049490
DOI: 10.1016/S2213-2600(22)00058-3 -
Respiratory Care Jun 2020Critical illness can threaten the adequacy of O delivery or CO excretion. Monitoring seeks to identify the adequacy of oxygenation and ventilation and to detect... (Review)
Review
Critical illness can threaten the adequacy of O delivery or CO excretion. Monitoring seeks to identify the adequacy of oxygenation and ventilation and to detect deterioration early. Advances in oximetry, capnography, and transcutaneous CO monitoring offer new opportunities for more accurate estimation of gas exchange, noninvasive monitoring of parameters previously not amenable (eg, total hemoglobin measurement), detection of disease, and prediction of fluid responsiveness.
Topics: Blood Gas Monitoring, Transcutaneous; Capnography; Critical Illness; Humans; Monitoring, Physiologic; Oximetry
PubMed: 32457167
DOI: 10.4187/respcare.07408 -
Ugeskrift For Laeger Mar 2020
Topics: Humans; Infant, Newborn; Neonatal Screening; Oximetry
PubMed: 32138822
DOI: No ID Found -
Translational Vision Science &... Feb 2021Similar to other organs, the retina relies on tightly regulated perfusion and oxygenation. Previous studies have demonstrated that retinal blood flow is affected in a... (Review)
Review
Similar to other organs, the retina relies on tightly regulated perfusion and oxygenation. Previous studies have demonstrated that retinal blood flow is affected in a variety of eye and systemic diseases, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Although measurement of peripheral oxygen saturation has become a standard clinical measurement through the development of pulse oximetry, developing a noninvasive technique to measure retinal oxygen saturation has proven challenging, and retinal oximetry technology currently remains inadequate for reliable clinical use. Here, we review current strategies and approaches, as well as several newer technologies in development, and discuss the future of retinal oximetry.
Topics: Diabetic Retinopathy; Humans; Oximetry; Oxygen; Retina; Retinal Vessels
PubMed: 34003890
DOI: 10.1167/tvst.10.2.5 -
BMC Medicine Aug 2022During the COVID-19 pandemic, there have been concerns regarding potential bias in pulse oximetry measurements for people with high levels of skin pigmentation. We... (Meta-Analysis)
Meta-Analysis
BACKGROUND
During the COVID-19 pandemic, there have been concerns regarding potential bias in pulse oximetry measurements for people with high levels of skin pigmentation. We systematically reviewed the effects of skin pigmentation on the accuracy of oxygen saturation measurement by pulse oximetry (SpO) compared with the gold standard SaO measured by CO-oximetry.
METHODS
We searched Ovid MEDLINE, Ovid Embase, EBSCO CINAHL, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform (up to December 2021) for studies with SpO-SaO comparisons and measuring the impact of skin pigmentation or ethnicity on pulse oximetry accuracy. We performed meta-analyses for mean bias (the primary outcome in this review) and its standard deviations (SDs) across studies included for each subgroup of skin pigmentation and ethnicity and used these pooled mean biases and SDs to calculate accuracy root-mean-square (A) and 95% limits of agreement. The review was registered with the Open Science Framework ( https://osf.io/gm7ty ).
RESULTS
We included 32 studies (6505 participants): 15 measured skin pigmentation and 22 referred to ethnicity. Compared with standard SaO measurement, pulse oximetry probably overestimates oxygen saturation in people with the high level of skin pigmentation (pooled mean bias 1.11%; 95% confidence interval 0.29 to 1.93%) and people described as Black/African American (1.52%; 0.95 to 2.09%) (moderate- and low-certainty evidence). The bias of pulse oximetry measurements for people with other levels of skin pigmentation or those from other ethnic groups is either more uncertain or suggests no overestimation. Whilst the extent of mean bias is small or negligible for all subgroups evaluated, the associated imprecision is unacceptably large (pooled SDs > 1%). When the extent of measurement bias and precision is considered jointly, pulse oximetry measurements for all the subgroups appear acceptably accurate (with A < 4%).
CONCLUSIONS
Pulse oximetry may overestimate oxygen saturation in people with high levels of skin pigmentation and people whose ethnicity is reported as Black/African American, compared with SaO. The extent of overestimation may be small in hospital settings but unknown in community settings. REVIEW PROTOCOL REGISTRATION: https://osf.io/gm7ty.
Topics: COVID-19; Humans; Oximetry; Oxygen; Oxygen Saturation; Pandemics; Skin Pigmentation
PubMed: 35971142
DOI: 10.1186/s12916-022-02452-8 -
Journal of Clinical Monitoring and... Feb 2021From home to intensive care units, innovations in pulse oximetry are susceptible to improve the monitoring and management of patients developing acute respiratory...
From home to intensive care units, innovations in pulse oximetry are susceptible to improve the monitoring and management of patients developing acute respiratory failure, and particularly those with the coronavirus disease 2019 (COVID-19). They include self-monitoring of oxygen saturation (SpO) from home, continuous wireless SpO monitoring on hospital wards, and the integration of SpO as the input variable for closed-loop oxygen administration systems. The analysis of the pulse oximetry waveform may help to quantify respiratory efforts and prevent intubation delays. Tracking changes in the peripheral perfusion index during a preload-modifying maneuver may be useful to predict preload responsiveness and rationalize fluid therapy.
Topics: COVID-19; Critical Care; Fluid Therapy; Home Care Services; Humans; Monitoring, Ambulatory; Monitoring, Physiologic; Oximetry; Oxygen; Oxygen Inhalation Therapy; Pandemics; Respiratory Insufficiency; SARS-CoV-2; Work of Breathing
PubMed: 32578070
DOI: 10.1007/s10877-020-00550-7 -
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 -
Respiratory Care Jun 2020Respiratory compromise is a common and potentially dangerous complication of patients admitted to general care units of hospitals. There are several distinct and... (Review)
Review
Respiratory compromise is a common and potentially dangerous complication of patients admitted to general care units of hospitals. There are several distinct and disparate pathophysiologic trajectories of respiratory deterioration that hospitalized patients may suffer. Obstructive sleep apnea and preexisting cardiopulmonary disease increase the risk of respiratory failure after major surgery. Patients in general care units of hospitals currently receive only intermittent monitoring of vital signs. Early warning systems that utilize analysis of intermittently collected vital signs may result in earlier recognition of clinical deterioration. Continuous monitoring of oximetry and capnography may allow the detection of pathophysiologic abnormalities earlier in patients in general care units, but the evidence for improved clinical outcomes remains weak. Increased monitoring may lead to increased monitor alarms that can have negative effects on patient care.
Topics: Capnography; Clinical Deterioration; Hospitals; Hospitals, General; Humans; Monitoring, Physiologic; Oximetry; Respiratory Insufficiency
PubMed: 32457176
DOI: 10.4187/respcare.07405 -
Sensors (Basel, Switzerland) Aug 2020Adequate oxygen delivery to a tissue depends on sufficient oxygen content in arterial blood and blood flow to the tissue. Oximetry is a technique for the assessment of... (Review)
Review
Adequate oxygen delivery to a tissue depends on sufficient oxygen content in arterial blood and blood flow to the tissue. Oximetry is a technique for the assessment of blood oxygenation by measurements of light transmission through the blood, which is based on the different absorption spectra of oxygenated and deoxygenated hemoglobin. Oxygen saturation in arterial blood provides information on the adequacy of respiration and is routinely measured in clinical settings, utilizing pulse oximetry. Oxygen saturation, in venous blood (SvO) and in the entire blood in a tissue (StO), is related to the blood supply to the tissue, and several oximetric techniques have been developed for their assessment. SvO can be measured non-invasively in the fingers, making use of modified pulse oximetry, and in the retina, using the modified Beer-Lambert Law. StO is measured in peripheral muscle and cerebral tissue by means of various modes of near infrared spectroscopy (NIRS), utilizing the relative transparency of infrared light in muscle and cerebral tissue. The primary problem of oximetry is the discrimination between absorption by hemoglobin and scattering by tissue elements in the attenuation measurement, and the various techniques developed for isolating the absorption effect are presented in the current review, with their limitations.
Topics: Humans; Monitoring, Physiologic; Oximetry; Oxygen; Spectroscopy, Near-Infrared
PubMed: 32867184
DOI: 10.3390/s20174844