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Respiratory Care Jun 2024Continuous monitoring of pulse oximetry (S ) is recommended during the 6-min walk test (6MWT) to ensure that the lowest S is recorded. In this case, severe exercise...
BACKGROUND
Continuous monitoring of pulse oximetry (S ) is recommended during the 6-min walk test (6MWT) to ensure that the lowest S is recorded. In this case, severe exercise induced desaturation (EID; S < 80%) triggers walking interruption by the examiner. Our main objective was to assess the impact of this approach on 6MWT distance in patients with chronic respiratory diseases and, second, to evaluate the safety of the test without interruption due to severe EID.
METHODS
6MWTs with continuous monitoring of S were prospectively performed in subjects with chronic respiratory disease. The participants were randomly allocated to walk with or without S real-time assessment. S visualization during the test execution was available only in the first group, and walking interruption was requested by the examiner if S < 80%.
RESULTS
One hundred forty-five participants were included in each group (68.6% females, 62 [52-69] y old) without differences in demographic and resting lung function parameters between them. The main respiratory conditions were COPD ( 101), asthma ( 73), pulmonary hypertension ( 47), and interstitial lung disease ( 39). The walked distance was similar comparing groups (349.5 ± 117.5 m vs 351.2 ± 105.4 m). Twenty-five subjects presented with severe EID in the group with real-time S assessment, and 20 subjects had severe EID in the group without real-time assessment respectively (overall prevalence of 15.5%). The 23 participants who had their test interrupted by the examiner due to severe EID in the first group (2 subjects stopped by themselves due to excessive symptoms) walked a shorter distance compared to the 11 subjects with severe EID without test interruption in the second group (9 subjects stopped by themselves due to excessive symptoms): 240.6 ± 100.2 m versus 345.9 ± 73.4 m. No exercise-related serious adverse events were observed.
CONCLUSIONS
Interruption driven by severe EID reduced the walked distance during the 6MWT. No serious adverse event, in turn, was observed in subjects with severe desaturation without real-time S assessment.
PubMed: 38834198
DOI: 10.4187/respcare.11751 -
JMIR Human Factors May 2024Pulse oximeters noninvasively measure blood oxygen levels, but these devices have rarely been designed for low-resource settings and are inconsistently available at...
Designing a Smartphone-Based Pulse Oximeter for Children in South Africa (Phefumla Project): Qualitative Analysis of Human-Centered Design Workshops With Health Care Workers.
BACKGROUND
Pulse oximeters noninvasively measure blood oxygen levels, but these devices have rarely been designed for low-resource settings and are inconsistently available at outpatient clinics.
OBJECTIVE
The Phefumla project aims to develop and validate a pediatric smartphone-based pulse oximeter designed specifically for this context. We present the process of human-centered oximeter design with health care workers in South Africa.
METHODS
We purposively sampled 19 health care workers from 5 clinics in Khayelitsha, Cape Town. Using a human-centered design approach, we conducted participatory workshops with four activities with health care workers: (1) they received 3D-printed prototypes of potential oximeter designs to provide feedback; (2) we demonstrated on dolls how they would use the novel oximeter; (3) they used pile sorting to rank design features and suggest additional features they desired; and (4) they designed their preferred user interface using a whiteboard, marker, and magnetized features that could be repositioned. We audio recorded the workshops, photographed outputs, and took detailed field notes. Analysis involved iterative review of these data to describe preferences, identify key design updates, and provide modifications.
RESULTS
Participants expressed a positive sentiment toward the idea of a smartphone pulse oximeter and suggested that a pediatric device would address an important gap in outpatient care. Specifically, participants expressed a preference for the prototype that they felt enabled more diversity in the way it could be used. There was a strong tendency to prioritize pragmatic design features, such as robustness, which was largely dictated by health care worker context. They also added features that would allow the oximeter device to serve other clinical functions in addition to oxygen saturation measurement, such as temperature and respiratory rate measurements.
CONCLUSIONS
Our end user-centered rapid participatory approach led to tangible design changes and prompted design discussions that the team had not previously considered. Overall, health care workers prioritized pragmatism for pediatric pulse oximeter device design.
Topics: Humans; South Africa; Smartphone; Oximetry; Health Personnel; Equipment Design; Qualitative Research; User-Centered Design; Child; Female; Male
PubMed: 38825834
DOI: 10.2196/54983 -
Computer Methods and Programs in... Aug 2024Measurement of blood pressure (BP) in ambulatory patients is crucial for at high-risk cardiovascular patients. A non-obtrusive, non-occluding device that continuously...
BACKGROUND & OBJECTIVES
Measurement of blood pressure (BP) in ambulatory patients is crucial for at high-risk cardiovascular patients. A non-obtrusive, non-occluding device that continuously measures BP via photoplethysmography will enable long-term ambulatory assessment of BP. The aim of this study is to validate the metasense 2PPG cuffless wearable design for continuous BP estimation without ECG.
METHODS
A customized high-speed electronic optical sensor architecture with laterally spaced reflectance pulse oximetry was designed into a simple unobtrusive low-power wearable in the form of a watch. 78 volunteers with a mean age of 32.72 ± 7.4 years (21 to 64), 51% male, 49% female were recruited with ECG-2PPG signals acquired. The fiducial features of the 2PPG morphologies were then attributed to the estimator. A 9-1 K-fold cross-validation was applied in the ML.
RESULTS
The correlation for PTT-SBP was 0.971 and for PTT-DBP was 0.954. The mean absolute error was 3.167±1.636 mmHg for SBP and 6.4 ± 3.9 mm Hg for DBP. The ambulatory estimate for SBP and DBP for an individual over 3 days with 8-hour recordings was 0.70-0.81 for SBP and 0.42-0.51 for DBP with a ± 2.65 mmHg for SBP and ±2.02 mmHg for DBP. For SBP, 98% of metasense measurements were within 15 mm Hg and for DBP, 91% of metasense measurements were within 10 mmHg CONCLUSIONS: The metasense device provides continuous, non-invasive BP estimations that are comparable to ambulatory BP meters. The portability and unobtrusiveness of this device, as well as the ability to continuously measure BP could one day enable long-term ambulatory BP measurement for precision cardiovascular therapeutic regimens.
Topics: Humans; Photoplethysmography; Female; Male; Adult; Wearable Electronic Devices; Middle Aged; Blood Pressure Determination; Blood Pressure; Young Adult; Equipment Design; Reproducibility of Results; Electrocardiography
PubMed: 38824806
DOI: 10.1016/j.cmpb.2024.108251 -
NPJ Digital Medicine Jun 2024Apnea and hypopnea are common sleep disorders characterized by the obstruction of the airways. Polysomnography (PSG) is a sleep study typically used to compute the...
Apnea and hypopnea are common sleep disorders characterized by the obstruction of the airways. Polysomnography (PSG) is a sleep study typically used to compute the Apnea-Hypopnea Index (AHI), the number of times a person has apnea or certain types of hypopnea per hour of sleep, and diagnose the severity of the sleep disorder. Early detection and treatment of apnea can significantly reduce morbidity and mortality. However, long-term PSG monitoring is unfeasible as it is costly and uncomfortable for patients. To address these issues, we propose a method, named DRIVEN, to estimate AHI at home from wearable devices and detect when apnea, hypopnea, and periods of wakefulness occur throughout the night. The method can therefore assist physicians in diagnosing the severity of apneas. Patients can wear a single sensor or a combination of sensors that can be easily measured at home: abdominal movement, thoracic movement, or pulse oximetry. For example, using only two sensors, DRIVEN correctly classifies 72.4% of all test patients into one of the four AHI classes, with 99.3% either correctly classified or placed one class away from the true one. This is a reasonable trade-off between the model's performance and the patient's comfort. We use publicly available data from three large sleep studies with a total of 14,370 recordings. DRIVEN consists of a combination of deep convolutional neural networks and a light-gradient-boost machine for classification. It can be implemented for automatic estimation of AHI in unsupervised long-term home monitoring systems, reducing costs to healthcare systems and improving patient care.
PubMed: 38824175
DOI: 10.1038/s41746-024-01139-z -
The Journal of Pediatrics May 2024To define percentile charts for arterial oxygen saturation (SpO), heart rate (HR), and cerebral oxygen saturation (crSO) during the first 15 minutes after birth in...
Reference Ranges for Arterial Oxygen Saturation, Heart Rate, and Cerebral Oxygen Saturation during Immediate Postnatal Transition in Neonates Born Extremely or Very Preterm.
OBJECTIVE
To define percentile charts for arterial oxygen saturation (SpO), heart rate (HR), and cerebral oxygen saturation (crSO) during the first 15 minutes after birth in neonates born very or extremely preterm and with favorable outcome.
STUDY DESIGN
We conducted a secondary-outcome analysis of preterm neonates included in the COSGOD III trial with visible cerebral oximetry measurements and with favorable outcome, defined as survival without cerebral injuries until term age. We excluded infants with inflammatory morbidities within the first week after birth. SpO was obtained by pulse oximetry, and electrocardiogram or pulse oximetry were used for measurement of HR. CrSO was assessed with near-infrared spectroscopy. Measurements were performed during the first 15 minutes after birth. Percentile charts (10 to 90 centile) were defined for each minute.
RESULTS
A total of 207 preterm neonates with a gestational age of 29.7 (23.9-31.9) weeks and a birth weight of 1200 (378-2320) grams were eligible for analyses. The 10 percentile of SpO at minute two, five, ten and 15 was 32%, 52%, 83% and 85%, respectively. The 10 percentile of HR at minute two, five, ten and 15 was 70bpm, 109bpm, 126bpm and 134bpm, respectively. The 10 percentile of crSO at minute two, five, ten and 15 was 15%, 27%, 59% and 63%, respectively.
CONCLUSIONS
This study provides new centile charts for SpO, HR, and crSO for extremely preterm neonates with favorable outcome. Implementing these centiles in guiding interventions during the stabilization process after birth might help to more accurately target oxygenation during postnatal transition period.
PubMed: 38823628
DOI: 10.1016/j.jpeds.2024.114132 -
European Journal of Applied Physiology Jun 2024Functional popliteal artery entrapment syndrome is a subtype of popliteal artery entrapment syndrome (PAES) without vascular disease or musculotendinous anomaly behind...
INTRODUCTION
Functional popliteal artery entrapment syndrome is a subtype of popliteal artery entrapment syndrome (PAES) without vascular disease or musculotendinous anomaly behind the knee. Symptoms are induced by popliteal artery extrinsic compression, leading to calf pain during lower limbs exercise. Non-invasive tests are still required to improve the diagnostic management of functional PAES. Exercise transcutaneous oxygen pressure (Ex-tcpO2) is of interest to provide objective arguments for the presence of regional blood flow impairment.
OBJECTIVES
The aim of the study was to analyze whether Ex-tcpO2 could serve as a non-invasive technique for detecting ischemia resulting from PAES.
METHODS
Patients with suspected PAES were recruited between 2017 and 2020. The diagnosis was confirmed or rejected, according to the surgical decision based on our diagnosis management involving a multidisciplinary team. Each patient underwent Ex-tcpO2 with specific maneuvers. The decrease from rest of oxygen pressure (DROP) index served for the interpretation of exercise results.
RESULTS
Sixty-five legs with suspected PAES were recruited. Diagnosis was confirmed in 34 (52.3%) and rejected in 32 (47.7%). The average DROP values found in confirmed and rejected group at left leg were - 21.6 ± 15.4 mmHg and - 10.9 ± 11.1 mmHg, respectively (p for Mann-Whitney 0.004), and - 15.8 ± 11 mmHg and - 11.1 ± 7.5 mmHg, respectively, at right leg (p = 0.088). Ex-tcpO2 sensitivity and specificity were 52.9% and 78.1%, respectively.
CONCLUSION
Ex-tcpO2 is an original non-invasive investigation for patients with claudication of doubtful arterial origin. The sensitivity and specificity are 52.9% and 78.1% in functional PAES diagnosis using 15 mmHg as threshold to detect ischemia during tiptoeing elevations.
PubMed: 38822882
DOI: 10.1007/s00421-024-05519-x -
European Journal of Medical Research May 2024Respiratory dysfunction is one of the most frequent symptoms observed during sepsis reflecting hypoxemia and/or acidosis that may be assessed by the ROX index (ratio of...
PURPOSE
Respiratory dysfunction is one of the most frequent symptoms observed during sepsis reflecting hypoxemia and/or acidosis that may be assessed by the ROX index (ratio of oxygen saturation by pulse oximetry/fraction of inspired oxygen to respiratory rate). This study aimed to describe the relationship between the prehospital ROX index and 30-day mortality rate among septic shock patients cared for in the prehospital setting by a mobile intensive care unit (MICU).
METHODS
From May 2016 to December 2021, 530 septic shock patients cared for by a prehospital MICU were retrospectively analysed. Initial ROX index value was calculated at the first contact with MICU. A Cox regression analysis after propensity score matching was performed to assess the relationship between 30-day mortality rate and a ROX index ≤ 10.
RESULTS
Pulmonary, digestive and urinary sepsis were suspected among 43%, 25% and 17% patients, respectively. The 30-day overall mortality reached 31%. Cox regression analysis showed a significant association between 30-day mortality and a ROX index ≤ 10: adjusted hazard ratio of 1.54 [1.08-2.31], p < 0.05.
CONCLUSIONS
During the prehospital stage of septic shock patients cared for by a MICU, ROX index is significantly associated with 30-day mortality. A prehospital ROX ≤ 10 value is associated with a 1.5-fold 30-day mortality rate increase. Prospective studies are needed to confirm the ability of prehospital ROX to predict sepsis outcome since the prehospital setting.
Topics: Humans; Shock, Septic; Male; Female; Aged; Middle Aged; Retrospective Studies; Oximetry; Oxygen Saturation; Aged, 80 and over; Respiratory Rate; Emergency Medical Services; Intensive Care Units; Oxygen
PubMed: 38822441
DOI: 10.1186/s40001-024-01902-8 -
Brain Stimulation 2024Dopaminergic neurons in the ventral tegmental area (VTA) are crucially involved in regulating arousal, making them a potential target for reversing general anesthesia....
BACKGROUND
Dopaminergic neurons in the ventral tegmental area (VTA) are crucially involved in regulating arousal, making them a potential target for reversing general anesthesia. Electrical deep brain stimulation (DBS) of the VTA restores consciousness in animals anesthetized with drugs that primarily enhance GABA receptors. However, it is unknown if VTA DBS restores consciousness in animals anesthetized with drugs that target other receptors.
OBJECTIVE
To evaluate the efficacy of VTA DBS in restoring consciousness after exposure to four anesthetics with distinct receptor targets.
METHODS
Sixteen adult Sprague-Dawley rats (8 female, 8 male) with bipolar electrodes implanted in the VTA were exposed to dexmedetomidine, fentanyl, ketamine, or sevoflurane to produce loss of righting, a proxy for unconsciousness. After receiving the dopamine D1 receptor antagonist, SCH-23390, or saline (vehicle), DBS was initiated at 30 μA and increased by 10 μA until reaching a maximum of 100 μA. The current that evoked behavioral arousal and restored righting was recorded for each anesthetic and compared across drug (saline/SCH-23390) condition. Electroencephalogram, heart rate and pulse oximetry were recorded continuously.
RESULTS
VTA DBS restored righting after sevoflurane, dexmedetomidine, and fentanyl-induced unconsciousness, but not ketamine-induced unconsciousness. D1 receptor antagonism diminished the efficacy of VTA stimulation following sevoflurane and fentanyl, but not dexmedetomidine.
CONCLUSIONS
Electrical DBS of the VTA restores consciousness in animals anesthetized with mechanistically distinct drugs, excluding ketamine. The involvement of the D1 receptor in mediating this effect is anesthetic-specific.
Topics: Animals; Ventral Tegmental Area; Sevoflurane; Rats, Sprague-Dawley; Dexmedetomidine; Male; Fentanyl; Rats; Female; Unconsciousness; Deep Brain Stimulation; Consciousness; Ketamine; Anesthetics, Inhalation
PubMed: 38821397
DOI: 10.1016/j.brs.2024.05.012 -
Skin Pigmentation and Pulse Oximeter Accuracy in the Intensive Care Unit: A Pilot Prospective Study.American Journal of Respiratory and... May 2024
PubMed: 38820169
DOI: 10.1164/rccm.202401-0036LE -
BMC Pulmonary Medicine May 2024Chronic obstructive lung disease (COPD) has diverse molecular pathomechanisms and clinical courses which, however, are not fully mirrored by current therapy....
Defining the role of exertional hypoxemia and pulmonary vasoconstriction on lung function decline, morbidity, and mortality in patients with chronic obstructive lung disease - the PROSA study: rationale and study design.
BACKGROUND
Chronic obstructive lung disease (COPD) has diverse molecular pathomechanisms and clinical courses which, however, are not fully mirrored by current therapy. Intermittent hypoxemia is a driver of lung function decline and poor outcome, e.g., in patients with concomitant obstructive sleep apnea. Transient hypoxemia during physical exercise has been suggested to act in a similar manner. The PROSA study is designed to prospectively assess whether the clinical course of COPD patients with or without exertional desaturation differs, and to address potential pathophysiological mechanisms and biomarkers.
METHODS
148 COPD patients (GOLD stage 2-3, groups B or C) will undergo exercise testing with continuous pulse oximetry. They will be followed for 36 months by spirometry, echocardiography, endothelial function testing, and biomarker analyses. Exercise testing will be performed by comparing the 6-min walk test (6MWT), bicycle ergometry, and a 15-sec breath-hold test. Exertional desaturation will be defined as SpO < 90% or delta-SpO ≥ 4% during the 6MWT. The primary endpoint will be the rate of decline of FEV1(LLN) between COPD patients with and without exertional desaturation.
DISCUSSION
The PROSA Study is an investigator-initiated prospective study that was designed to prove or dismiss the hypothesis that COPD patients with exertional desaturation have a significantly more rapid rate of decline of lung function as compared to non-desaturators. A 20% difference in the primary endpoint was considered clinically significant; it can be detected with a power of 90%. If the primary endpoint will be met, exercise testing with continuous pulse oximetry can be used as a ubiquitously available, easy screening tool to prospectively assess the risk of rapid lung function decline in COPD patients at an early disease stage. This will allow to introduce personalized, risk-adapted therapy to improve COPD outcome in the long run. PROSA is exclusively funded by public funds provided by the European Research Council through an ERC Advanced Grant. Patient recruitment is ongoing; the PROSA results are expected to be available in 2028.
TRIAL REGISTRATION
The PROSA Study has been prospectively registered at clinicaltrials.gov (register no. NCT06265623, dated 09.02.2024).
Topics: Aged; Female; Humans; Male; Middle Aged; Exercise Test; Forced Expiratory Volume; Hypoxia; Lung; Oximetry; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Spirometry; Vasoconstriction; Walk Test; Observational Studies as Topic
PubMed: 38816826
DOI: 10.1186/s12890-024-03074-x