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1.
Physiol Meas ; 44(5)2023 06 01.
Article in English | MEDLINE | ID: covidwho-2312302

ABSTRACT

Objective. Pulse oximetry is a non-invasive optical technique used to measure arterial oxygen saturation (SpO2) in a variety of clinical settings and scenarios. Despite being one the most significant technological advances in health monitoring over the last few decades, there have been reports on its various limitations. Recently due to the Covid-19 pandemic, questions about pulse oximeter technology and its accuracy when used in people with different skin pigmentation have resurfaced, and are to be addressed.Approach. This review presents an introduction to the technique of pulse oximetry including its basic principle of operation, technology, and limitations, with a more in depth focus on skin pigmentation. Relevant literature relating to the performance and accuracy of pulse oximeters in populations with different skin pigmentation are evaluated.Main Results. The majority of the evidence suggests that the accuracy of pulse oximetry differs in subjects of different skin pigmentations to a level that requires particular attention, with decreased accuracy in patients with dark skin.Significance. Some recommendations, both from the literature and contributions from the authors, suggest how future work could address these inaccuracies to potentially improve clinical outcomes. These include the objective quantification of skin pigmentation to replace currently used qualitative methods, and computational modelling for predicting calibration algorithms based on skin colour.


Subject(s)
COVID-19 , Skin Pigmentation , Humans , Pandemics , Oximetry/methods , Oxygen
2.
Am J Epidemiol ; 192(5): 714-719, 2023 05 05.
Article in English | MEDLINE | ID: covidwho-2310420

ABSTRACT

While medical technology is typically considered neutral, many devices rely upon racially biased algorithms that prioritize care for White patients over Black patients, who may require more urgent medical attention. In their accompanying article, Sudat et al. (Am J Epidemiol. 2023;XXX(XX):XXX-XXX) document striking inaccuracies in pulse oximeter readings among Black patients, with significant clinical implications. Their findings suggest that this resulted in racial differences in delivery of evidence-based care during the coronavirus disease 2019 (COVID-19) pandemic, affecting admissions and treatment protocols. Despite the medical community's growing awareness of the pulse oximeter's significant design flaw, the device is still in use. In this article, I contextualize Sudat et al.'s study results within the larger history of racial bias in medical devices by highlighting the consequences of the continued underrepresentation of diverse populations in clinical trials. I probe the implications of racially biased assessments within clinical practice and research and illustrate the disproportionate impact on patients of color by examining 2 medical tools, the pulse oximeter and pulmonary function tests. Both cases result in the undertreatment and underdiagnosis of Black patients. I also demonstrate how the social underpinnings of racial bias in medical technology contribute to poor health outcomes and reproduce health disparities, and propose several recommendations for the field to rectify the harms of racial bias in medical technology.


Subject(s)
COVID-19 , Equipment and Supplies , Racism , Humans , Black or African American , Oximetry/methods , Pandemics
3.
J Correct Health Care ; 29(2): 143-149, 2023 04.
Article in English | MEDLINE | ID: covidwho-2265475

ABSTRACT

SARS-CoV-2 has spread quickly despite the implementation of various strategies to limit the spread of the disease. Current screening procedures are unable to detect asymptomatic infections. This study reports the prevalence of abnormal vital signs among incarcerated individuals with asymptomatic infections and proposes an enhanced screening algorithm that may detect asymptomatic infections. A case control study used a retrospective electronic chart review of COVID-19 infected people and matched controls housed in one Federal Bureau of Prisons institution. Data were collected on age, body mass index, medical history, temperature, blood oxygen saturation (SpO2), and symptoms. Fifty-seven laboratory-confirmed COVID-19 infections and 81 confirmed controls were identified. Asymptomatic infections were present in 35/57 people (61%) with a group minimum SpO2 94.4% (standard deviation [SD] 1.4) and a maximum oral temperature of 99.19°F (SD 0.36). An enhanced screening algorithm that uses pulse oximetry yields a sensitivity of 84.2%, 95% confidence interval [72.1-92.5]. Among asymptomatic people, there is a high prevalence of abnormal SpO2 and temperature measurements. A screening algorithm that uses both of these measures can detect asymptomatic infections with a low false positive rate.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , Case-Control Studies , Retrospective Studies , Asymptomatic Infections/epidemiology , SARS-CoV-2 , Oximetry/methods
4.
Pediatr Crit Care Med ; 24(6): 458-462, 2023 06 01.
Article in English | MEDLINE | ID: covidwho-2279985

ABSTRACT

OBJECTIVES: Pulse oximetry (Sp o2 ) may overestimate arterial oxygen saturation (Sa o2 ) in blood laboratory testing. This study aimed to assess Sp o2 -Sa o2 difference in relation to race (i.e., patient self-reporting as Black or White), occult hypoxemia, and length of stay (LOS) in pediatric patients with COVID-19. DESIGN: Single-center retrospective study in pediatric COVID-19 patients. We used multivariable linear regressions to examine the association between race and oximetry measurements and between occult hypoxemia and LOS. Oximetry bias was defined using Sp o2 and Sa o2 data according to approved comparisons. Occult hypoxemia was defined as Sp o2 greater than 92% and Sa o2 less than 88%. SETTING: Quaternary pediatric hospital. PATIENTS: Pediatric COVID-19 patients admitted to Texas Children's Hospital between May 2020 and December 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 2713 patients with complete physiological data in the analysis. Of the total, 61% were Black, and 39% were White. Oximetry bias was greater in Black compared with White patients ( p < 0.001), and this bias increased as the oxygen saturations decreased ( p < 0.001). Black and White patients had a 12% and 4% prevalence of occult hypoxemia, respectively ( p < 0.001). LOS was not associated with oximetry bias or occult hypoxemia once controlled for the level of support (intensive care, respiratory, circulatory). CONCLUSIONS: We found an oximetry bias in the measurement of Sp o2 with respect to Sa o2 in symptomatic hospitalized pediatric patients with the diagnosis of COVID-19. Furthermore, race is related to an increased oximetry bias. However, we did not find a relationship between oximetry bias and the LOS in the hospital in this cohort of patients.


Subject(s)
COVID-19 , Oxygen , Humans , Child , Retrospective Studies , Oximetry/methods , Hypoxia/diagnosis
5.
Sensors (Basel) ; 23(5)2023 Feb 25.
Article in English | MEDLINE | ID: covidwho-2269584

ABSTRACT

The early identification of microvascular changes in patients with Coronavirus Disease 2019 (COVID-19) may offer an important clinical opportunity. This study aimed to define a method, based on deep learning approaches, for the identification of COVID-19 patients from the analysis of the raw PPG signal, acquired with a pulse oximeter. To develop the method, we acquired the PPG signal of 93 COVID-19 patients and 90 healthy control subjects using a finger pulse oximeter. To select the good quality portions of the signal, we developed a template-matching method that excludes samples corrupted by noise or motion artefacts. These samples were subsequently used to develop a custom convolutional neural network model. The model accepts PPG signal segments as input and performs a binary classification between COVID-19 and control samples. The proposed model showed good performance in identifying COVID-19 patients, achieving 83.86% accuracy and 84.30% sensitivity (hold-out validation) on test data. The obtained results indicate that photoplethysmography may be a useful tool for microcirculation assessment and early recognition of SARS-CoV-2-induced microvascular changes. In addition, such a noninvasive and low-cost method is well suited for the development of a user-friendly system, potentially applicable even in resource-limited healthcare settings.


Subject(s)
COVID-19 , Photoplethysmography , Humans , Photoplethysmography/methods , SARS-CoV-2 , Oximetry/methods , Oxygen , Neural Networks, Computer , Signal Processing, Computer-Assisted , Heart Rate
6.
Adv Exp Med Biol ; 1395: 391-396, 2022.
Article in English | MEDLINE | ID: covidwho-2173628

ABSTRACT

The current COVID-19 pandemic has shown us that the pulse oximeter is a key medical device for monitoring blood-oxygen levels non-invasively in patients with chronic or acute illness. It has also emphasised limitations in accuracy for individuals with darker skin pigmentation, calling for new methods to provide better measurements. The aim of our study is to identify the impact of skin pigmentation on pulse oximeter measurements. We also explored the benefits of a multi-wavelength approach with an induced change of arterial oxygen saturation. A total of 20 healthy volunteers were recruited. We used time domain diffuse reflectance spectroscopy (TDDRS) from a broad band light source, collecting spectra from the index finger along with three different pulse oximeters used simultaneously for monitoring purposes. Five acute hypoxic events were induced by administering 11% FiO2, produced by a Hypoxico altitude training system, for 120 sec through a face mask with a one-way valve. Our multi-wavelength approach revealed a correlation between the signature of skin pigmentation and the dynamic range of oxygen saturation measurements. Principal component analysis (PCA) showed separation between a range of different pigmented volunteers (PC1 = 56.00%) and oxygen saturation (PC2 = 22.99%). This emphasises the need to take into account skin pigmentation in oximeter measurements. This preliminary study serves to validate the need to better understand the impact of skin pigmentation absorption on optical readings in pulse oximeters. Multi-wavelength approaches have the potential to enable robust and accurate measurements across diverse populations.


Subject(s)
COVID-19 , Skin Pigmentation , Humans , Pilot Projects , Altitude , Pandemics , Oximetry/methods , Hypoxia , Oxygen
7.
PLoS One ; 17(10): e0273402, 2022.
Article in English | MEDLINE | ID: covidwho-2079731

ABSTRACT

BACKGROUND: The pathophysiology of COVID-19 remains poorly understood. We aimed to estimate the contribution of intrapulmonary shunting and ventilation-to-perfusion (VA/Q) mismatch using a mathematical model to construct oxygen-haemoglobin dissociation curves (ODCs). METHODS: ODCs were constructed using transcutaneous pulse oximetry at two different fractions of inspired oxygen (FiO2). 199 patients were included from two large district general hospitals in the South East of England from 1st to 14th January 2021. The study was supported by the National Institute of Health Research (NIHR) Clinical Research Network. RESULTS: Overall mortality was 29%. Mean age was 68.2 years (SEM 1·2) with 46% female. Median shunt on admission was 17% (IQR 8-24.5); VA/Q was 0.61 (IQR 0.52-0.73). Shunt was 37.5% higher in deaths (median 22%, IQR 9-29) compared to survivors (16%, 8-21; p = 0.0088) and was a predictor of mortality (OR 1.04; 95% CI 1.01-1.07). Admission oxygen saturations were more strongly predictive of mortality (OR 0.91, 95% CI 0.87-0.96). There was no difference in VA/Q mismatch between deaths (0.60; IQR 0.50-0.73) and survivors (0.61; IQR 0.52-0.73; p = 0.63) and it was not predictive of mortality (OR 0.68; 95% CI 0.18-2.52; p = 0.55). Shunt negatively correlated with admission oxygen saturation (R -0.533; p<0.0001) whereas VA/Q was not (R 0.1137; p = 0.12). INTERPRETATION: Shunt, not VA/Q mismatch, was associated with worsening hypoxia, though calculating shunt was not of prognostic value. This study adds to our understanding of the pathophysiology of hypoxaemia in COVID-19. Our inexpensive and reliable technique may provide further insights into the pathophysiology of hypoxia in other respiratory diseases.


Subject(s)
COVID-19 , Lung Diseases , Humans , Female , Aged , Male , Ventilation-Perfusion Ratio/physiology , Hypoxia , Oximetry/methods , Oxygen/physiology
8.
BMC Med ; 20(1): 267, 2022 08 16.
Article in English | MEDLINE | ID: covidwho-1993362

ABSTRACT

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 (SpO2) compared with the gold standard SaO2 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 SpO2-SaO2 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 (Arms) 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 SaO2 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 Arms < 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 SaO2. The extent of overestimation may be small in hospital settings but unknown in community settings. REVIEW PROTOCOL REGISTRATION: https://osf.io/gm7ty.


Subject(s)
COVID-19 , Skin Pigmentation , Humans , Oximetry/methods , Oxygen , Oxygen Saturation , Pandemics
9.
JAMA Intern Med ; 182(7): 730-738, 2022 07 01.
Article in English | MEDLINE | ID: covidwho-1872108

ABSTRACT

Importance: Pulse oximetry guides triage and therapy decisions for COVID-19. Whether reported racial inaccuracies in oxygen saturation measured by pulse oximetry are present in patients with COVID-19 and associated with treatment decisions is unknown. Objective: To determine whether there is differential inaccuracy of pulse oximetry by race or ethnicity among patients with COVID-19 and estimate the association of such inaccuracies with time to recognition of eligibility for oxygen threshold-specific COVID-19 therapies. Design, Setting, and Participants: This retrospective cohort study of clinical data from 5 referral centers and community hospitals in the Johns Hopkins Health System included patients with COVID-19 who self-identified as Asian, Black, Hispanic, or White. Exposures: Concurrent measurements (within 10 minutes) of oxygen saturation levels in arterial blood (SaO2) and by pulse oximetry (SpO2). Main Outcomes and Measures: For patients with concurrent SpO2 and SaO2 measurements, the proportion with occult hypoxemia (SaO2<88% with concurrent SpO2 of 92%-96%) was compared by race and ethnicity, and a covariate-adjusted linear mixed-effects model was produced to estimate the association of race and ethnicity with SpO2 and SaO2 difference. This model was applied to identify a separate sample of patients with predicted SaO2 levels of 94% or less before an SpO2 level of 94% or less or oxygen treatment initiation. Cox proportional hazards models were used to estimate differences by race and ethnicity in time to recognition of eligibility for guideline-recommended COVID-19 therapies, defined as an SpO2 level of 94% or less or oxygen treatment initiation. The median delay among individuals who ultimately had recognition of eligibility was then compared. Results: Of 7126 patients with COVID-19, 1216 patients (63 Asian [5.2%], 478 Black [39.3%], 215 Hispanic [17.7%], and 460 White [37.8%] individuals; 507 women [41.7%]) had 32 282 concurrently measured SpO2 and SaO2. Occult hypoxemia occurred in 19 Asian (30.2%), 136 Black (28.5%), and 64 non-Black Hispanic (29.8%) patients compared with 79 White patients (17.2%). Compared with White patients, SpO2 overestimated SaO2 by an average of 1.7% among Asian (95% CI, 0.5%-3.0%), 1.2% among Black (95% CI, 0.6%-1.9%), and 1.1% among non-Black Hispanic patients (95% CI, 0.3%-1.9%). Separately, among 1903 patients with predicted SaO2 levels of 94% or less before an SpO2 level of 94% or less or oxygen treatment initiation, compared with White patients, Black patients had a 29% lower hazard (hazard ratio, 0.71; 95% CI, 0.63-0.80), and non-Black Hispanic patients had a 23% lower hazard (hazard ratio, 0.77; 95% CI, 0.66-0.89) of treatment eligibility recognition. A total of 451 patients (23.7%) never had their treatment eligibility recognized, most of whom (247 [54.8%]) were Black. Among the remaining 1452 (76.3%) who had eventual recognition of treatment eligibility, Black patients had a median delay of 1.0 hour (95% CI, 0.23-1.9 hours; P = .01) longer than White patients. There was no significant median difference in delay between individuals of other racial and ethnic minority groups and White patients. Conclusions and Relevance: The results of this cohort study suggest that racial and ethnic biases in pulse oximetry accuracy were associated with greater occult hypoxemia in Asian, Black, and non-Black Hispanic patients with COVID-19, which was associated with significantly delayed or unrecognized eligibility for COVID-19 therapies among Black and Hispanic patients. This disparity may contribute to worse outcomes among Black and Hispanic patients with COVID-19.


Subject(s)
COVID-19 , Ethnicity , COVID-19/therapy , Cohort Studies , Female , Humans , Hypoxia , Minority Groups , Oximetry/methods , Oxygen , Retrospective Studies
10.
Early Hum Dev ; 166: 105552, 2022 03.
Article in English | MEDLINE | ID: covidwho-1683075

ABSTRACT

BACKGROUND: Partial oxygen saturation (SpO2) increases within minutes during transition from the intrauterine to extrauterine life. This study aims to determine the postnatal course of pulmonary regional oxygen saturation (rSO2) measured by Near-Infrared Spectroscopy (NIRS). METHODS: We conducted an observational study at the delivery room in infants above 35 weeks of gestation who did not need resuscitation and did not develop respiratory distress. Preductal pulse oximetry (Covidien NellcorTM) and right pulmonary apex oxygen saturation (raSO2) and basal oxygen saturation (rbSO2) (Covidien INVOSTM) were measured, starting from the postnatal third minute of life, until the 15th minute. The correlations between SpO2 and pulmonary rSO2 were analyzed. RESULTS: Of the 110 infants included in the study, 87 were term and 23 were late preterms. The gestational age and birth weight were 38.5 ± 1.36 weeks and 3285 ± 508 g, respectively. Median (5th-95th percentile) raSO2 and rbSO2 were 79% (58-95%) and 78% (46-95%) at the third minute, respectively. The rSO2 values measured from both sides increased and reached a steady-state around postnatal 9 min, similar to SpO2 values. The pulmonary NIRS values were significantly higher for babies born by C-Section compared to babies born by vaginal delivery (p < 0.05). CONCLUSION: We found that rSO2 measurements increased within minutes in the postnatal period in late preterm and term babies without respiratory distress and reached a plateau at the postnatal 9th minute. The normal values obtained from this preliminary study may be used to predict the prognosis of cases with respiratory distress.


Subject(s)
Oxygen Saturation , Oxygen , Female , Gestational Age , Humans , Infant , Infant, Newborn , Oximetry/methods , Pregnancy , Spectroscopy, Near-Infrared
11.
J Cyst Fibros ; 20 Suppl 3: 57-63, 2021 12.
Article in English | MEDLINE | ID: covidwho-1587342

ABSTRACT

BACKGROUND: Cystic fibrosis (CF) programs and people with CF (PwCF) employed various monitoring methods for virtual care during the COVID-19 pandemic. This paper characterizes experiences with remote monitoring across the U.S. CF community. METHODS: The CF Foundation (CFF) sponsored distribution of home spirometers (April 2020 to May 2021), surveys to PwCF and CF programs (July to September 2020), and a second program survey (April to May 2021). We used mixed methods to explore access, use, and perspectives regarding the use of remote monitoring in future care. RESULTS: By October 2020, 13,345 spirometers had been distributed, and 19,271 spirometers by May 2021. Programs (n=286) estimated proportions of PwCF with home devices increased over seven months: spirometers (30% to 70%), scales (50% to 70%), oximeters (5% to 10%) with higher estimates in adult programs for spirometers and oximeters. PwCF (n=378) had access to scales (89%), followed by oximeters (48%) and spirometers (47%), often using scales and oximeters weekly, and spirometers monthly. Over both surveys, some programs had no method to collect respiratory specimens for cultures associated with telehealth visits (47%, n=132; 41%, n=118). Most programs (81%) had a process for phlebotomy associated with a telehealth visit, primarily through off-site labs. Both PwCF and programs felt future care should advance remote monitoring and recommended improvements for access, training, and data collection systems. CONCLUSIONS: PwCF and programs experienced unprecedented access to remote monitoring and raised its importance for future care. Improvements to current systems may leverage these shared experiences to augment future care models.


Subject(s)
COVID-19 , Cystic Fibrosis , Equipment and Supplies/supply & distribution , Home Care Services , Monitoring, Physiologic/methods , Spirometry , Adult , COVID-19/epidemiology , COVID-19/prevention & control , Child , Cystic Fibrosis/diagnosis , Cystic Fibrosis/epidemiology , Cystic Fibrosis/therapy , Delivery of Health Care/organization & administration , Delivery of Health Care/trends , Health Services Accessibility/organization & administration , Health Services Accessibility/standards , Home Care Services/organization & administration , Home Care Services/standards , Humans , Models, Organizational , Needs Assessment , Oximetry/instrumentation , Oximetry/methods , Quality Improvement , SARS-CoV-2 , Spirometry/instrumentation , Spirometry/methods , Telemedicine/methods , Telemedicine/standards , United States/epidemiology
12.
S Afr Med J ; 111(10): 950-956, 2021 09 03.
Article in English | MEDLINE | ID: covidwho-1478411

ABSTRACT

BACKGROUND: The phenomenon of silent hypoxaemia has been described in patients with COVID-19 pneumonia, which is characterised by low oxygen saturation levels of <90% in those who appear clinically well and do not show signs of significant respiratory distress. OBJECTIVES: To assess the impact on clinical outcomes for high-risk COVID-19 patients using a pulse oximeter to monitor oxygen saturation levels in a home setting. METHODS: We performed a retrospective cohort analysis using data from a large South African insurance administrator. Patients were categorised as high risk, based on age and specific underlying clinical conditions, or from predictive models derived from medical scheme administrative claims data. The impact of pulse oximetry home monitoring on COVID-19 clinical outcomes was investigated by the use of Cox proportional hazard models. RESULTS: Between 2 March 2020 and 31 October 2020, of 38 660 patients analysed, 8 115 were in the intervention group. The 60-day mortality rate for the evaluated high-risk population was 1.35%. After adjusting for age and comorbidity differences, the intervention group was found to have an adjusted hazard ratio of 0.52 (p<0.0001). No statistical significance was found between the intervened and control groups for admission to hospital, admission to intensive care unit (ICU) and use of mechanical ventilation. The intervention group had a lower median C-reactive protein (CRP) level on admission (p=0.03). After adjustment for admission CRP levels, elevated CRP was associated with an increased mortality (p<0.0001), while the statistical significance in mortality between the intervention and the control group was lost. CONCLUSIONS: High-risk COVID-19 patients who used a pulse oximeter to monitor oxygen saturation levels had significantly lower mortality rates compared with other high-risk patients. The mortality benefit may be explained by earlier presentation to hospital, as suggested by lower initial CRP levels.


Subject(s)
COVID-19/physiopathology , Hospitalization/statistics & numerical data , Oximetry/methods , Oxygen Saturation , Adult , C-Reactive Protein/metabolism , COVID-19/mortality , Cohort Studies , Female , Humans , Intensive Care Units/statistics & numerical data , Male , Middle Aged , Respiration, Artificial/statistics & numerical data , Retrospective Studies , Severity of Illness Index , South Africa
13.
Chest ; 161(4): 971-978, 2022 04.
Article in English | MEDLINE | ID: covidwho-1439285

ABSTRACT

BACKGROUND: Pulse oximeters may produce less accurate results in non-White patients. RESEARCH QUESTION: Do pulse oximeters detect arterial hypoxemia less effectively in Black, Hispanic, and/or Asian patients than in White patients in respiratory failure and about to undergo extracorporeal membrane oxygenation (ECMO)? STUDY DESIGN AND METHODS: Data on adult patients with respiratory failure readings 6 h before ECMO were provided by the Extracorporeal Life Support Organization registry. Data was collected from 324 centers between January 2019 and July 2020. Our primary analysis was of rates of occult hypoxemia-low arterial oxygen saturation (Sao2 ≤ 88%) on arterial blood gas measurement despite a pulse oximetry reading in the range of 92% to 96%. RESULTS: The rate of pre-ECMO occult hypoxemia, that is, arterial oxygen saturation (Sao2) ≤ 88%, was 10.2% (95% CI, 6.2%-15.3%) for 186 White patients with peripheral oxygen saturation (Spo2) of 92% to 96%; 21.5% (95% CI, 11.3%-35.3%) for 51 Black patients (P = .031 vs White); 8.6% (95% CI, 3.2%-17.7%) for 70 Hispanic patients (P = .693 vs White); and 9.2% (95% CI, 3.5%-19.0%) for 65 Asian patients (P = .820 vs White). Black patients with respiratory failure had a statistically significantly higher risk of occult hypoxemia with an OR of 2.57 (95% CI, 1.12-5.92) compared with White patients (P = .026). The risk of occult hypoxemia for Hispanic and Asian patients was equivalent to that of White patients. In a secondary analysis of patients with Sao2 ≤ 88% despite Spo2 > 96%, Black patients had more than three times the risk compared with White patients (OR, 3.52; 95% CI, 1.12-11.10; P = .032). INTERPRETATION: Compared with White patients, the prevalence of occult hypoxemia was higher in Black patients than in White patients about to undergo ECMO for respiratory failure, but it was comparable in Hispanic and Asian patients compared with White patients.


Subject(s)
Extracorporeal Membrane Oxygenation , Racism , Respiratory Insufficiency , Adult , Humans , Hypoxia/diagnosis , Hypoxia/etiology , Oximetry/methods , Oxygen , Respiratory Insufficiency/diagnosis , Respiratory Insufficiency/therapy , Retrospective Studies
14.
Anaesthesia ; 77(2): 143-152, 2022 02.
Article in English | MEDLINE | ID: covidwho-1429480

ABSTRACT

Pulse oximetry is used widely to titrate oxygen therapy and for triage in patients who are critically ill. However, there are concerns regarding the accuracy of pulse oximetry in patients with COVID-19 pneumonitis and in patients who have a greater degree of skin pigmentation. We aimed to determine the impact of patient ethnicity on the accuracy of peripheral pulse oximetry in patients who were critically ill with COVID-19 pneumonitis by conducting a retrospective observational study comparing paired measurements of arterial oxygen saturation measured by co-oximetry on arterial blood gas analysis (SaO2 ) and the corresponding peripheral oxygenation saturation measured by pulse oximetry (Sp O2 ). Bias was calculated as the mean difference between SaO2 and Sp O2 measurements and limits of agreement were calculated as bias ±1.96 SD. Data from 194 patients (135 White ethnic origin, 34 Asian ethnic origin, 19 Black ethnic origin and 6 other ethnic origin) were analysed consisting of 6216 paired SaO2 and Sp O2 measurements. Bias (limits of agreement) between SaO2 and Sp O2 measurements was 0.05% (-2.21-2.30). Patient ethnicity did not alter this to a clinically significant degree: 0.28% (1.79-2.35), -0.33% (-2.47-2.35) and -0.75% (-3.47-1.97) for patients of White, Asian and Black ethnic origin, respectively. In patients with COVID-19 pneumonitis, Sp O2 measurements showed a level of agreement with SaO2 values that was in line with previous work, and this was not affected by patient ethnicity.


Subject(s)
COVID-19/physiopathology , Ethnicity/statistics & numerical data , Oximetry/methods , Oximetry/standards , Oxygen Saturation/physiology , COVID-19/therapy , Critical Care/methods , Female , Humans , Male , Middle Aged , Oxygen Inhalation Therapy/methods , Reproducibility of Results , Retrospective Studies , SARS-CoV-2
17.
Chest ; 160(1): e9-e12, 2021 07.
Article in English | MEDLINE | ID: covidwho-1122270

ABSTRACT

Patients with COVID-19 report severe respiratory symptoms consistent with ARDS. The clinical presentation of ARDS in COVID-19 is often atypical, as patients with COVID-19 exhibit a disproportionate hypoxemia compared with relatively preserved lung mechanics. This pattern is more similar to neonatal respiratory distress syndrome secondary to surfactant deficiency, which has been shown to benefit from exogenous surfactant. We present our experience with exogenous surfactant treatment in a patient with COVID-19 experiencing COVID-19-related ARDS. The patient responded with improved oxygenation, and we believe surfactant was the catalyst for the successful extubation and clinical improvement of the patient.


Subject(s)
Biological Products/administration & dosage , COVID-19 , Critical Care/methods , Hypoxia , Patient Positioning/methods , Antiviral Agents/administration & dosage , COVID-19/blood , COVID-19/diagnostic imaging , COVID-19/physiopathology , COVID-19/therapy , Drug Monitoring/methods , Extracorporeal Membrane Oxygenation/methods , Humans , Hypoxia/etiology , Hypoxia/therapy , Lung/diagnostic imaging , Male , Middle Aged , Oximetry/methods , Pulmonary Surfactants/administration & dosage , Respiration, Artificial/methods , SARS-CoV-2/isolation & purification , Treatment Outcome
18.
Cardiol Young ; 30(9): 1339-1342, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-1082976
19.
Obstet Gynecol ; 136(5): 1025-1029, 2020 11.
Article in English | MEDLINE | ID: covidwho-1059683

ABSTRACT

BACKGROUND: There are limited data regarding treatment options for pregnant women with severe coronavirus disease 2019 (COVID-19). CASE: A 35-year-old primigravid patient at 22 weeks of gestation presented with 7 days of fever, cough, anosmia, and dyspnea. Nasopharyngeal swab was positive for the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and a chest X-ray demonstrated bilateral patchy infiltrates. Laboratory evaluation was notable for marked elevation of interleukin-6 and C-reactive protein concentrations. On hospital day 3, owing to increased dyspnea and oxygen requirement, the patient was treated with tocilizumab followed by 5 days of remdesivir. She responded well, recovered to room air, and was discharged home after a 9-day hospitalization. CONCLUSION: Tocilizumab and remdesivir may be effective for treatment of severe COVID-19 in pregnancy, but additional data are needed to guide risk-benefit considerations.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antibodies, Monoclonal, Humanized/administration & dosage , Coronavirus Infections , Lung/diagnostic imaging , Pandemics , Pneumonia, Viral , Pregnancy Complications, Infectious , Adenosine Monophosphate/administration & dosage , Adult , Alanine/administration & dosage , Antiviral Agents/administration & dosage , Betacoronavirus/isolation & purification , C-Reactive Protein/analysis , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/drug therapy , Coronavirus Infections/physiopathology , Female , Humans , Interleukin-6/blood , Oximetry/methods , Pneumonia, Viral/blood , Pneumonia, Viral/diagnosis , Pneumonia, Viral/drug therapy , Pneumonia, Viral/etiology , Pneumonia, Viral/physiopathology , Pregnancy , Pregnancy Complications, Infectious/blood , Pregnancy Complications, Infectious/diagnosis , Pregnancy Complications, Infectious/drug therapy , Radiography, Thoracic/methods , SARS-CoV-2 , Treatment Outcome , COVID-19 Drug Treatment
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