Browsing by Subject "Oximetry"
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Item Determination of Respiratory Depression Measured by Capnography of Acutely Intoxicated Patients Presenting to an Urban Emergency Department(2015-01-26) Danko, Colin; Au, Vincent; Onisko, Nancy S.; Severson, Katie; Kleinschmidt, KurtINTRODUCTION: The standard of care for monitoring the respiratory status of patients with altered sensorium until recently has been pulse oximetry and observation. While pulse oximetry measures peripheral arterial oxygen saturation, it does not adequately detect hypoventilatory status. We hypothesized that intoxicated patients would demonstrate clinically significant signs of hypoventilation and that ETCO2 monitoring may detect these changes earlier than pulse oximetry. METHODS: This was a pilot observational data collection study of intoxicated patients presenting to a single urban emergency department between June 6, 2014 and August 1, 2014. Research assistants (RA's) monitored the ED tracking board for patients presenting with chief complaints suggesting possible intoxication with drugs or alcohol. Patients eligible for enrollment were between age 18-80 years, had a baseline Rikers Sedation Agitation Scale Score of < 3 and the treating ED physician believed that the patient's altered mental status was "possibly" or "probably" related to use of an intoxicant. Vital sign data and end-tidal CO2 readings were collected at Baseline, 30, 60, 90 and 120 minutes then hourly there after. End points for data collection were: 1) demonstration of alertness for at least 60 consecutive minutes 2) disposition to home or another hospital department or 3) decompensating respiratory status requiring bi-pap, c-pap or intubation. RESULTS: Seven hundred ninety four patients were screened. Thirty-five met all enrollment criteria and were assigned a de-identified patient number. Six patients were excluded from the final data analysis (5 for critical errors in ETCO2 data collection and 1 had AMS of non-intoxication etiology). Of the remaining 29 patients, 20 were male, 9 female. Ages ranged from 19-54 yrs. Alcohol was one of the intoxicants in almost half of patients. Other intoxicants included benzodiazepines, synthetic cannabinoids, cocaine, heroin and diet pills. Some patients had exposure to more than one intoxicant. ETCO2 values of > 45 mmHg were considered indicators of hypoventilatory state. There were a total of 19 episodes of hypoventilatory status as indicated by ETCO2 > 45 mmHg. Of the patients with multiple episodes (> 2) of hypoventilatory status, two had used heroin, one 62 mg lorazepam. Pulse oximetry reflected a normal oxygen saturation during at least 6 of the episodes. CONCLUSION: ETCO2 may detect hypoventilatory status before pulse oximetry and should be standard of care in patients presenting with intoxication associated with CNS depression.Item Race and ethics in the design of biomedical technologies: the pulse oximeter as a case in point (The Daniel W. Foster, M.D., Visiting Lectureship in Medical Ethics)(2021-11-09) Berne, Rosalyn W.There were clear indications from studies done in 2005 and 2007 that pulse oximeters overestimate arterial oxygen saturation during hypoxia in dark-skinned individuals. And yet, years later, the device remains essentially unaltered. This disregard has been particularly significant during the coronavirus pandemic. Patients diagnosed with COVID-19 who present with silent hypoxemia, but are not sick enough to warrant hospital admission, have been guided to monitor their arterial oxygenation by pulse oximetry at home, and present for care when they show evidence of hypoxemia. Others in the general public have used the device simply for personal assurance. Whether or not these uses are appropriate is debatable. Nevertheless, that a racial bias is embedded in this technology is indisputable. The pulse oximeter serves as a timely case in point of how race can become a matter of ethics in the design of biomedical devices.Item Use of the Masimo Rainbow Noninvasive Hemoglobin Measurement Technology for Children with Sickle Cell Disease(2012-08-15) Farris, Landon; Szmuk, PeterPURPOSE OF STUDY: Until recently, pulse oximeters have been limited by the fact that they use two wavelengths of light to measure oxygen saturation. The use of only two wavelengths often resulted in serious errors, especially in patients with hemoglobinopathies. Although multiwavelength pulse oximeters have been the subject of research in the past, the first multiwavelength instruments did not reach the commercial medical market until 2005. More recently, the new ‘Rainbow Technology’ pulse oximeters developed by Masimo Corp., which also use multiple wavelengths, have permitted the noninvasive measurement of total hemoglobin. To further evaluate the accuracy of this new technology, we intended to test the hypothesis that the total hemoglobin as measured by the Masimo Rainbow Radical correlates with laboratory data in children with sickle cell anemia as measured by the Sysmex Automated Hematology Analyzer. METHODS USED: Hemoglobin measurements were taken at Children’s Medical Center in Dallas from patients under the age of 18 with a diagnosis of sickle cell anemia. In addition, the study limits enrollment to patients which are scheduled for routine hemoglobin measurements as part of their clinical course. A single use, flexible probe is applied on the middle finger of the hand from which blood is drawn, and the monitor is allowed to run for 3-5 minutes until the readings are stabilized. Only the readings taken at the time of the blood draw are recorded as SpHb values and used for subsequent analysis. SUMMARY OF RESULTS: 150 patients were enrolled, and the device completed measurements on 133 of the patients. The Masimo Rainbow Radical recorded a total hemoglobin measurement an average of 17 minutes from when blood was taken for laboratory analysis. The hemoglobin values as measured by the Radical (SpHb) and the Sysmex Automated Hematology Analyzer (Hb) differed by an average absolute value of 1.26 g/dL. Additionally, when the SpHb measurements are plotted against the Hb values, the Pearson Correlation Coefficient is 0.69. The mean bias was 0.8 g/dL with a standard deviation of 1.3 g/dL and limits of agreement of -1.8 to 3.4 g/dL. SpHb. CONCLUSIONS: The bias and precision of SpHb to Hb in our patients was higher than that found in healthy volunteers. This might be due to the different sensors used in adults and children, or may be due to the presence of sickle hemoglobin in our patients. Further studies are needed to clarify this issue. However, at this preliminary stage, the correlation between the Rainbow Radical and Hematology Analyzer suggests that the multiwavelength technology could be used as a substitute for routine screening hemoglobin measurement by blood draw.