Ambient Light Affects Pulse Oximeters

Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.

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“…light modulation filtering, Webster (1997)). Ambient light interference in PPG-based systems has also been discussed by Hanowell et al (1987).…”

Section: Photoplethysmography Instrumentationmentioning

confidence: 99%

Photoplethysmography and its application in clinical physiological measurement

2007

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“…This “S” shaped curve starts to plummet at the low 90% range. It is important to note that while pulse oximetry can accurately detect blood oxygenation when compared to Arterial Blood Gas, 38,39 it functions on the ability to detect modulation in transmitted light and thus various factors such as nail polish and ambient light 40,41 or low perfusion 39,42 could impact the accuracy of the readings.…”

Section: Discussionmentioning

confidence: 99%

Emergency Department Vital Signs and Outcomes After Discharge

Gabayan

Gould

Weiss

et al. 2017

Academic Emergency Medicine

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Objective Vital signs are critical markers of illness severity in the Emergency Department (ED). Providers need to understand the abnormal vital signs in older adults that are problematic. We hypothesized that in patients age ≥ 65 years discharged from the ED, there are abnormal vital signs that are associated with an admission to an inpatient bed within 7 days of discharge. Methods We conducted a retrospective cohort study using data from a regional integrated health system of members age ≥ 65 years during the years 2009–2010. We used univariate contingency tables to assess the relationship between hospital admission within 7 days of discharge and vital sign (including systolic blood pressure, heart rate, body temperature, and pulse oximetry (Sp02) values measured closest to discharge) using standard thresholds for abnormal and thresholds derived from the study data‥ Results Of 104,025 ED discharges, 4,638 (4.5%) were followed by inpatient admission within 7-days. Vital signs had a greater odds of admission beyond a single cut-off. The vital signs with at least twice the odds of admission were systolic blood pressure ≤ 97 mmHg (OR 2.02, 95% CI 1.57–2.60), heart rate ≥ 101 bpm (OR 2.00 95% CI 1.75–2.29), body temperature ≥99.2 degrees Fahrenheit (OR 2.14, 95% CI 1.90–2.41), and pulse oximetry ≤ 92 Sp02 (OR 2.04, 95% CI 1.55–2.68). Patients with two vital sign abnormalities per the analysis had the highest odds of admission. A majority of patients discharged with abnormal vital signs per the analysis were not admitted within 7 days of ED discharge. Conclusion While we found a majority of patients discharged with abnormal vital signs as defined by the analysis, not to be admitted after discharge, we identified vital signs associated with at least twice the odds of admission.

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“…Obwohl Lichteinfall aus der Umgebung -zumindest theoretisch -die Pulsoximetrie nicht beeinflussen sollte, sind Fallbeschreibungen mit Störungen durch Licht beschrieben [7,11,14,20,35]. Einige Autoren berichten von einer routinemäßigen Abdeckung der Messfühler mit Aluminiumfolie [46,58].…”

Section: Bei Einer Halbwertszeit Von Co-hb Von üBer 8 H Werden Bei Raunclassified

Atemnotanfälle im Rettungsdienst

Meissner

Fabel

2000

Notfall & Rettungsmedizin

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Ambient Light Affects Pulse Oximeters

Cited by 58 publications

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Photoplethysmography and its application in clinical physiological measurement

Photoplethysmography and its application in clinical physiological measurement

Emergency Department Vital Signs and Outcomes After Discharge

Atemnotanfälle im Rettungsdienst

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