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Biomedical Optics Express Apr 2024Pulse oximetry represents a ubiquitous clinical application of optics in modern medicine. Recent studies have raised concerns regarding the potential impact of...
Pulse oximetry represents a ubiquitous clinical application of optics in modern medicine. Recent studies have raised concerns regarding the potential impact of confounders, such as variable skin pigmentation and perfusion, on blood oxygen saturation measurement accuracy in pulse oximeters. Tissue-mimicking phantom testing offers a low-cost, well-controlled solution for characterizing device performance and studying potential error sources, which may thus reduce the need for costly in vivo trials. The purpose of this study was to develop realistic phantom-based test methods for pulse oximetry. Material optical and mechanical properties were reviewed, selected, and tuned for optimal biological relevance, e.g., oxygenated tissue absorption and scattering, strength, elasticity, hardness, and other parameters representing the human finger's geometry and composition, such as blood vessel size and distribution, and perfusion. Relevant anatomical and physiological properties are summarized and implemented toward the creation of a preliminary finger phantom. To create a preliminary finger phantom, we synthesized a high-compliance silicone matrix with scatterers for embedding flexible tubing and investigated the addition of these scatterers to novel 3D printing resins for optical property control without altering mechanical stability, streamlining the production of phantoms with biologically relevant characteristics. Phantom utility was demonstrated by applying dynamic, pressure waveforms to produce tube volume change and resultant photoplethysmography (PPG) signals. 3D printed phantoms achieved more biologically relevant conditions compared to molded phantoms. These preliminary results indicate that the phantoms show strong potential to be developed into tools for evaluating pulse oximetry performance. Gaps, recommendations, and strategies are presented for continued phantom development.
PubMed: 38633081
DOI: 10.1364/BOE.518967 -
Respirology (Carlton, Vic.) Dec 2023
Topics: Humans; Oximetry; Sleep Apnea, Obstructive
PubMed: 37882673
DOI: 10.1111/resp.14615 -
MedRxiv : the Preprint Server For... Oct 2023Pulse oximeters measure peripheral arterial oxygen saturation (SpO ) noninvasively, while the gold standard (SaO ) involves arterial blood gas measurement. There are...
Pulse oximeters measure peripheral arterial oxygen saturation (SpO ) noninvasively, while the gold standard (SaO ) involves arterial blood gas measurement. There are known racial and ethnic disparities in their performance. BOLD is a new comprehensive dataset that aims to underscore the importance of addressing biases in pulse oximetry accuracy, which disproportionately affect darker-skinned patients. The dataset was created by harmonizing three Electronic Health Record databases (MIMIC-III, MIMIC-IV, eICU-CRD) comprising Intensive Care Unit stays of US patients. Paired SpO and SaO measurements were time-aligned and combined with various other sociodemographic and parameters to provide a detailed representation of each patient. BOLD includes 49,099 paired measurements, within a 5-minute window and with oxygen saturation levels between 70-100%. Minority racial and ethnic groups account for ∼25% of the data - a proportion seldom achieved in previous studies. The codebase is publicly available. Given the prevalent use of pulse oximeters in the hospital and at home, we hope that BOLD will be leveraged to develop debiasing algorithms that can result in more equitable healthcare solutions.
PubMed: 37873343
DOI: 10.1101/2023.10.03.23296485 -
Journal of Thoracic Disease Jul 2023There is a significant burden of sleep disordered breathing (SDB) in patients living with severe and complex obesity undergoing pre-bariatric surgery assessment. This...
BACKGROUND
There is a significant burden of sleep disordered breathing (SDB) in patients living with severe and complex obesity undergoing pre-bariatric surgery assessment. This longitudinal observational study evaluated the burden of obesity hypoventilation syndrome (OHS) in this cohort of patients and the therapeutic compliance of patients commenced on positive airway pressure treatment.
METHODS
All pre-bariatric surgery patients referred to the sleep clinic for review after an abnormal screening study between 2018 and 2022 were included. We collected data on their sleep study results, anthropometrics, co-morbid medical conditions, clinical observations, spirometry and arterial blood gas (ABG). Patients commenced on therapy were followed-up longitudinally and compliance data collected via remote monitoring.
RESULTS
A total of 116 patients were included [age: mean ± standard deviation (SD) 48.8±10.8 years; body mass index (BMI) 49.2±8.5 kg/m; Epworth Sleepiness Scale (ESS) 8.7±5.1 points]. Fifteen patients (12.9% of cohort) were diagnosed with hypercapnic respiratory failure (pH 7.40±0.02; pO 11.00±1.04 kPa; pCO 6.15±0.08 kPa). Compared to eucapnic obstructive sleep apnoea (OSA) patients, they were older (51.1 48.5 years; P=0.311), had a higher BMI (51.5 48.9 kg/m; P=0.266), more likely to be female (66.7% 53.5%; P=0.275) and had a higher ESS score (10.4 8.5 points; P=0.177). On binomial regression analysis insulin dependent diabetes was the only patient characteristic of significance with prevalence increased in patients with OHS (26.7% 8.9%; P=0.042). Forced vital capacity (FVC) and oxygen saturation (SpO) cut-offs demonstrated high specificity (96.8%) but low sensitivity (13.3%) to diagnosed hypercapnia. Fifty percent of the patients with hypercapnia required bi-level ventilation. On follow-up 44.9% of patients were compliant with therapy (>4 hours usage/night).
CONCLUSIONS
In minimally symptomatic patients living with severe and complex obesity who have an abnormal overnight oximetry, over 1 in 10 demonstrated chronic respiratory failure. Clinic spirometry and daytime SpO excluded those with hypercapnia. Overall adherence to prescribed therapy is low. Screening, appropriate pre-operative optimisation and peri-operative planning are important in preventing complications in this patient cohort.
PubMed: 37559648
DOI: 10.21037/jtd-23-112 -
Food Chemistry Feb 2024This study aimed to introduce a new method based on isothermal calorimetry (IC) for measuring the autoxidation rate in mayonnaise samples. Mayonnaise samples were...
This study aimed to introduce a new method based on isothermal calorimetry (IC) for measuring the autoxidation rate in mayonnaise samples. Mayonnaise samples were prepared by homogenizing an aqueous phase, consisting of vinegar and egg yolk, with various oil phases, including sunflower, corn, extra virgin olive, grape seed, and apple seed oils at 60 °C. The rate of free radical formation (R) was controlled by adding AIBN (R = 4.4±0.1×10 M/s). The autoxidation rate determined by IC was highly correlated with the one measured using the oxygen uptake method (R = 0.99). The IC method accurately indicated the antioxidant capacity and rates of both inhibited and uninhibited periods, together with the oxidizability of mayonnaise samples. The mayonnaise made with extra virgin olive oil exhibited the lowest oxidizability, while sunflower oil showed maximum antioxidant efficiency. A significant advantage of the IC method was its ability to simultaneously measure up to 24 samples with minimal effort.
PubMed: 37666126
DOI: 10.1016/j.foodchem.2023.137274 -
JAMA Network Open Nov 2023An extrauterine placental perfusion (EPP) approach for physiological-based cord clamping (PBCC) may support infants with very low birth weight (VLBW) during transition... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
An extrauterine placental perfusion (EPP) approach for physiological-based cord clamping (PBCC) may support infants with very low birth weight (VLBW) during transition without delaying measures of support.
OBJECTIVE
To test whether EPP in resuscitation of infants with VLBW results in higher hematocrit levels, better oxygenation, or improved infant outcomes compared with delayed cord clamping (DCC).
DESIGN, SETTING, AND PARTICIPANTS
This nonblinded, single-center randomized clinical trial was conducted at a tertiary care neonatal intensive care unit. Infants with a gestational age greater than 23 weeks and birth weight less than 1500 g born by cesarean delivery between May 2019 and June 2021 were included. Data were analyzed from October through December 2021.
INTERVENTION
Prior to cesarean delivery, participants were allocated to receive EPP or DCC. In the EPP group, infant and placenta, connected by an intact umbilical cord, were detached from the uterus and transferred to the resuscitation unit. Respiratory support was initiated while holding the placenta over the infant. The umbilical cord was clamped when infants showed regular spontaneous breathing, stable heart rates greater than 100 beats/min, and adequate oxygen saturations. In the DCC group, cords were clamped 30 to 60 seconds after birth before infants were transferred to the resuscitation unit, where respiratory support was started.
MAIN OUTCOMES AND MEASURE
The primary outcome was the mean hematocrit level in the first 24 hours after birth. Secondary prespecified outcome parameters comprised oxygenation during transition and short-term neonatal outcome.
RESULTS
Among 60 infants randomized and included, 1 infant was excluded after randomization; there were 29 infants in the EPP group (mean [SD] gestational age, 27 weeks 6 days [15.0 days]; 14 females [48.3%]) and 30 infants in the DCC group (mean [SD] gestational age, 28 weeks 1 day [17.1 days]; 17 females [56.7%]). The mean (SD) birth weight was 982.8 (276.6) g and 970.2 (323.0) g in the EPP and DCC group, respectively. Intention-to-treat analysis revealed no significant difference in mean hematocrit level (mean difference [MD], 2.1 percentage points; [95% CI, -2.2 to 6.4 percentage points]). During transition, infants in the EPP group had significantly higher peripheral oxygen saturation as measured by pulse oximetry (adjusted MD at 5 minutes, 15.3 percentage points [95% CI, 2.0 to 28.6 percentage points]) and regional cerebral oxygen saturation (adjusted MD at 5 minutes, 11.3 percentage points [95% CI, 2.0 to 20.6 percentage points]). Neonatal outcome parameters were similar in the 2 groups.
CONCLUSIONS AND RELEVANCE
This study found that EPP resulted in similar hematocrit levels as DCC, with improved cerebral and peripheral oxygenation during transition. These findings suggest that EPP may be an alternative procedure for PBCC in infants with VLBW.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT03916159.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Birth Weight; Infant, Premature; Infant, Very Low Birth Weight; Perfusion; Placenta; Male
PubMed: 37921769
DOI: 10.1001/jamanetworkopen.2023.40597 -
Arthritis Care & Research Mar 2024Systemic juvenile idiopathic arthritis-associated lung disease (SJIA-LD) is a life-threatening disease complication. Key questions remain regarding clinical course and...
OBJECTIVE
Systemic juvenile idiopathic arthritis-associated lung disease (SJIA-LD) is a life-threatening disease complication. Key questions remain regarding clinical course and optimal treatment approaches. The objectives of the study were to detail management strategies after SJIA-LD detection, characterize overall disease courses, and measure long-term outcomes.
METHODS
This was a prospective cohort study. Clinical data were abstracted from the electronic medical record, including current clinical status and changes since diagnosis. Serum biomarkers were determined and correlated with presence of LD.
RESULTS
We enrolled 41 patients with SJIA-LD, 85% with at least one episode of macrophage activation syndrome and 41% with adverse reactions to a biologic. Although 93% of patients were alive at last follow-up (median 2.9 years), 37% progressed to requiring chronic oxygen or other ventilator support, and 65% of patients had abnormal overnight oximetry studies, which changed over time. Eighty-four percent of patients carried the HLA-DRB1*15 haplotype, significantly more than patients without LD. Patients with SJIA-LD also showed markedly elevated serum interleukin-18 (IL-18), variable C-X-C motif chemokine ligand 9 (CXCL9), and significantly elevated matrix metalloproteinase 7. Treatment strategies showed variable use of anti-IL-1/6 biologics and addition of other immunomodulatory treatments and lung-directed therapies. We found a broad range of current clinical status independent of time from diagnosis or continued biologic treatment. Multidomain measures of change showed imaging features were the least likely to improve with time.
CONCLUSION
Patients with SJIA-LD had highly varied courses, with lower mortality than previously reported but frequent hypoxia and requirement for respiratory support. Treatment strategies were highly varied, highlighting an urgent need for focused clinical trials.
Topics: Child; Humans; Arthritis, Juvenile; Prospective Studies; Lung; Lung Diseases; Macrophage Activation Syndrome; Disease Progression
PubMed: 37691306
DOI: 10.1002/acr.25234 -
Medicine Jul 2023We aimed to investigate whether the unusual clinical presentation of pulmonary embolism (PE) varies by the type of provocation. In this retrospective cohort study, we...
We aimed to investigate whether the unusual clinical presentation of pulmonary embolism (PE) varies by the type of provocation. In this retrospective cohort study, we examined the electronic health records (EHR) records of all patients diagnosed with PE (upon presentation or during hospitalization) presented to our tertiary hospital during 2014 to 2019. Inclusion criteria were the diagnosis of acute PE and age above 18 years. Excluded were all patients to whom complete EHR were not available. The primary outcome was the main presenting symptom, categorized by a multidisciplinary consensus expert committee as either typical or atypical of PE. Comorbidities, vital signs, medications and laboratory results on presentations were recorded. 591 patients were included in the final analysis. Dyspnea was significantly less common and hemoptysis and chest pain more common in the unprovoked PE group (35%, 5%, and 25%, respectively) compared with nonmalignant (42.6%, 0%, and 16.3%) and malignancy-associated (47.7%, 0.9%, and 8.2%) PE (Pv = 0.02, 0.002 and 0.001, respectively). No recorded symptoms were the third most common presentation overall, accounting for a significantly (Pv < 0.001) higher proportion of PE patients with malignancy (19%) whereas atypical presentation was the hallmark of patients with nonmalignant provokation (19.7%) (Pv = 0.005). Accounting for multiple potential confounders, the risk of atypical or asymptomatic presentation was higher with lower heart rates (RR = 0.974 95%C.I. [0.957-0.990]) and higher pulse oximetry saturation (RR = 1.114 95%CI [1.034-1.201]). The clinical presentation of PE varies with different types of provoking factors, with atypical presentation most common in nonmalignant provocation and asymptomatic presentation most prevalent in patients with underlying malignancy. Further studies are needed to determine the effect of said variance on long term clinical outcomes.
Topics: Adolescent; Humans; Chest Pain; Comorbidity; Neoplasms; Pulmonary Embolism; Retrospective Studies; Risk Factors; Adult
PubMed: 37443506
DOI: 10.1097/MD.0000000000034224 -
Cureus Oct 2023Hemodynamic monitoring of neonates is crucial because neonates are easily and acutely susceptible to hemodynamic disturbances. As such, non-invasive monitoring of... (Review)
Review
Hemodynamic monitoring of neonates is crucial because neonates are easily and acutely susceptible to hemodynamic disturbances. As such, non-invasive monitoring of hemodynamics is preferable. It has been postulated that non-invasive pulse oximetry determines the perfusion index and pulse variability index and provides accurate measurements to predict hemodynamic changes in preterm or term infants. Equally, numerous studies have investigated the efficacy of perfusion and pulse variability indices in monitoring neonatal hemodynamics. The aim of this study was to systematically review studies that have delved into the role of perfusion and pulse variability indices in the assessment of neonatal hemodynamics. The study collected data from 2010-2023 using the patient, intervention, comparison, outcome (PICO) search strategy using the databases PubMed, Scopus, and Excerpta Medica database (Embase). A total of 616 articles were evaluated based on their appropriateness and relevance; we included seven studies. As per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic review. Our study concluded that these indices were effective in measuring hemodynamics.
PubMed: 38046508
DOI: 10.7759/cureus.48058 -
Journal of Clinical Monitoring and... Dec 2023Pulse oximeter accuracy is important for the quality and safety of patient care. Methodological errors occurring during pulse oximeter accuracy studies can confound... (Review)
Review
PURPOSE
Pulse oximeter accuracy is important for the quality and safety of patient care. Methodological errors occurring during pulse oximeter accuracy studies can confound results. One potential source of error during pulse oximeter comparison studies is optical interference due to sensor-to-sensor crosstalk. Optical crosstalk can occur whenever pulse oximeter sensors are tested in close proximity of one another, as occurs during pulse oximeter comparison studies.
METHODS
This publication represents the first comprehensive review of sensor-to-sensor crosstalk and other forms of optical interference during pulse oximeter comparison studies. A review of the published literature was undertaken to elucidate the mechanism of optical crosstalk, along with other forms of optical interference, and a solution (shielding) is offered.
RESULTS
When pulse oximeter sensors are placed close to each other, as occurs during comparison studies, the red and near-infrared light used can also enter an adjacent sensor and lead to error. Pulse oximeter manufacturers have designed systems to reject some forms of optical interference, such as ambient light. However, light emanating from adjacent sensors during comparison studies can cause artifact, and this can be exacerbated by sensor malposition. Proper sensor placement and use of optical shielding are the best solutions to prevent crosstalk.
CONCLUSIONS
Crosstalk and other forms of optical interference can corrupt pulse oximeter readings. Proper sensor placement and use of optical shielding of sensors are crucial steps to help protect the integrity of the data. Studies to further characterize crosstalk during pulse oximeter comparison studies are needed.
Topics: Humans; Oximetry; Oxygen; Infrared Rays
PubMed: 37610524
DOI: 10.1007/s10877-023-01060-y