Measurements of Arterial Occlusion Pressure Using Hand-Held Devices.

ABSTRACT: Vehrs, PR, Reynolds, S, Allen, J, Barrett, R, Blazzard, C, Burbank, T, Hart, H, Kasper, N, Lacey, R, Lopez, D, and Fellingham, GW. Measurements of arterial occlusion pressure using hand-held devices. J Strength Cond Res 38(5): 873-880, 2024-Arterial occlusion pressure (AOP) of the brachial artery was measured simultaneously using Doppler ultrasound (US), a hand-held Doppler (HHDOP), and a pulse oximeter (PO) in the dominant (DOM) and nondominant (NDOM) arms of males ( n = 21) and females ( n = 23) using continuous (CONT) and incremental (INCR) cuff inflation protocols. A mixed-model analysis of variance revealed significant ( p < 0.05) overall main effects between AOP measured using a CONT (115.7 ± 10.9) or INCR (115.0 ± 11.5) cuff inflation protocol; between AOP measured using US (116.3 ± 11.2), HHDOP (115.4 ± 11.2), and PO (114.4 ± 11.2); and between males (120.7 ± 10.6) and females (110.5 ± 9.4). The small overall difference (1.81 ± 3.3) between US and PO measures of AOP was significant ( p < 0.05), but the differences between US and HHDOP and between HHDOP and PO measures of AOP were not significant. There were no overall differences in AOP between the DOM and NDOM arms. Trial-to-trial variance in US measurements of AOP was not significant when using either cuff inflation protocol but was significant when using HHDOP and PO and a CONT cuff inflation protocol. Bland-Altman plots revealed reasonable limits of agreement for both HHDOP and PO measures of AOP. The small differences in US, HHDOP, and PO measurements of AOP when using CONT or INCR cuff inflation protocols are of minimal practical importance. The choice of cuff inflation protocol is one of personal preference. Hand-held Doppler of PO can be used to assess AOP before using blood flow restriction during exercise.

Oximetria de pulso neonatal: capacitação de profissionais e estudantes da saúde no formato remoto e presencial / Neonatal pulse oximetry: training healthcare professionals and students in remote and on-site format / Pulsioximetría neonatal: formación de profesionales y estudiantes de la salud a distancia y presencial

Introdução:A oximetria de pulso neonatal compõe o Programa Nacional de Triagem Neonatal do Brasil desde 2014. Entretanto, existem poucos registros de sua efetiva implementação na rotina de cuidados materno-infantis no país.Objetivo:O objetivo deste trabalho foi relatar a experiência em ações de educação em saúde a profissionais e estudantes da área da saúde e à população em geral, em temas relacionados ao Teste do Coraçãozinho.Metodologia:Trata-se de um estudo descritivo, do tipo relato de experiência, executado entre julho de 2019 a julho de 2021, antes e durante a pandemia de Covid-19, por discentes vinculados ao projeto de extensão de serviço universitário de referência do Rio Grande do Norte. O público-alvo das capacitações foram estudantes e profissionais do curso de Medicina, Enfermagem e Técnico de Enfermagem dos municípios de Natal, Macaíba, Santa Cruz, Currais Novos, Mossoró e Caicó, do estado do Rio Grande do Norte. Foi realizada uma capacitação no formato presencial antes da pandemia causada pela COVID-19 ou no formato remoto como adaptação das atividades durante o período pandêmico. A metodologia dos treinamentos foi composta por um formulário de pré e pós teste visando avaliar a eficácia das capacitações, somado a fundamentação teórica, simulações teórico-práticas e discussão de casos clínicos. Além disso, foram promovidas ações educativas destinadas à população geral. Resultados:As capacitações ministradas a profissionais e estudantes da área da saúde totalizaram 1212 participantes. Os eventos direcionados ao meio externo, como transmissões ao vivo e conteúdos audiovisuais em redes sociais, atingiram 12.931 pessoas. O fomento à produção científica envolveu a elaboração de 95 trabalhos aprovados em congressos regionais, nacionais e internacionais, bem como a organização de um congresso internacional nas áreas de Pediatria e Cardiologia, contabilizando 29.007 inscritos.Conclusões:Evidenciou-se a importância de intervenções para melhoria da linha de cuidado à criança cardiopata (AU).

Introduction:Neonatal pulse oximetry has been part of the National Newborn Screening Program in Brazil since 2014. However, there are few reports of its effective implementation in routine maternal and child care in the country. Objective: This study reports on the experience of providing health education to health professionals, students and the general population on topics related to neonatal pulse oximetry.Methodology: This is a descriptive study, experience report type, carried out between July 2019 and July 2021,before and during the Covid-19 pandemic, by students linked to the extension project of a reference university service in Rio Grande do Norte. The target audience of the training were students and professionals from the Medicine, Nursing and Nursing Technician course in the municipalities of Natal, Macaíba, Santa Cruz, Currais Novos, Mossoró and Caicó, in the state of Rio Grande do Norte. Training was carried out in person before the COVID-19 pandemic or remotely as an adaptation of activities during the pandemic period. The training methodology consisted of a pre-and post-test form aimed at evaluating the effectiveness of the training, in addition to theoretical foundations, theoretical-practical simulations and discussion of clinical cases. In addition, educational activities were promoted for the general population.Results:Training given to health professionals and students totaled 1212 participants. Events directed to the external environment, such as live broadcasts and audiovisual content on socialnetworks, reached 12,931 people. Promotion of scientific production involved the preparation of 95 papers approved in regional, national, and international congresses, as well as the organization of an international congress in the areas of Pediatrics andCardiology, with 29,007 registered participants. Conclusions: The importance of interventions to improve the line of care for children with heart disease was evidenced (AU).

Introducción: La oximetría de pulso neonatal forma parte del Programa Nacional de Tamizaje Neonatal en Brasil desde 2014. Sin embargo, existen pocos registros de su implementación efectiva en la atención materno-infantil de rutina en el país. Objetivo: El objetivo de este trabajo fue relatar la experiencia en acciones de educación en salud para profesionales y estudiantes del área de la salud y la población en general, sobre temas relacionados con El Test del Corazoncito. Metodología:Se trata de un estudiodescriptivo, del tipo relato de experiencia, realizado entre julio de 2019 y julio de 2021, antes y durante la pandemia de la Covid-19, por estudiantes vinculados al proyecto de extensión de un servicio universitario de referencia en Rio Grande Norte. El público objetivo de la capacitación fueron estudiantes y profesionales de la carrera de Medicina, Enfermería y Técnico en Enfermería de los municipios de Natal, Macaíba, Santa Cruz, Currais Novos, Mossoró y Caicó, en el estado de Rio Grande do Norte. La formación se realizó en formato presencial antes de la pandemia causada por el COVID-19 o a distancia como adaptación de las actividades durante el periodo de pandemia. La metodología de capacitación consistió en un formulario de pre y post test dirigido a evaluar la efectividad de la capacitación, además de fundamentos teóricos, simulacros teórico-prácticos y discusión de casos clínicos. Además, se promovieron actividades educativas para la población en general. Resultados:La formación impartida a profesionales y estudiantes de la salud totalizó 1212 participantes. Los eventos dirigidos al entorno externo, como retransmisiones en directo y contenidos audiovisuales en redes sociales, llegaron a 12.931 personas. El fomento de la producción científica implicó la elaboración de 95 trabajos aprobados en congresos regionales, nacionales e internacionales, así como la organización de un congreso internacional en las áreas de Pediatría y Cardiología, con 29.007 inscritos. Conclusiones:Se destacó la importancia de las intervenciones para mejorar la línea de atención a los niños con cardiopatías (AU).

Remote Blood Oxygen Estimation From Videos Using Neural Networks.

Peripheral blood oxygen saturation (SpO 2) is an essential indicator of respiratory functionality and received increasing attention during the COVID-19 pandemic. Clinical findings show that COVID-19 patients can have significantly low SpO 2 before any obvious symptoms. Measuring an individual's SpO 2 without having to come into contact with the person can lower the risk of cross contamination and blood circulation problems. The prevalence of smartphones has motivated researchers to investigate methods for monitoring SpO 2 using smartphone cameras. Most prior schemes involving smartphones are contact-based: They require using a fingertip to cover the phone's camera and the nearby light source to capture reemitted light from the illuminated tissue. In this paper, we propose the first convolutional neural network based noncontact SpO 2 estimation scheme using smartphone cameras. The scheme analyzes the videos of an individual's hand for physiological sensing, which is convenient and comfortable for users and can protect their privacy and allow for keeping face masks on. We design explainable neural network architectures inspired by the optophysiological models for SpO 2 measurement and demonstrate the explainability by visualizing the weights for channel combination. Our proposed models outperform the state-of-the-art model that is designed for contact-based SpO 2 measurement, showing the potential of the proposed method to contribute to public health. We also analyze the impact of skin type and the side of a hand on SpO 2 estimation performance.

Pulse Oximeters and Violation of Federal Antidiscrimination Law.

This Viewpoint discusses how some pulse oximeters can provide incorrect oxygen saturation data for dark-skinned patients compared with light-skinned patients, describes the reasons that biased oximeters remained in use, and highlights why a rule recently proposed by the US Department of Health and Human Services may bring about needed change in the use of pulse oximetry for patients with dark skin.

Materialized Oppression in Medical Tools and Technologies.

It is well-known that racism is encoded into the social practices and institutions of medicine. Less well-known is that racism is encoded into the material artifacts of medicine. We argue that many medical devices are not merely biased, but materialize oppression. An oppressive device exhibits a harmful bias that reflects and perpetuates unjust power relations. Using pulse oximeters and spirometers as case studies, we show how medical devices can materialize oppression along various axes of social difference, including race, gender, class, and ability. Our account uses political philosophy and cognitive science to give a theoretical basis for understanding materialized oppression, explaining how artifacts encode and carry oppressive ideas from the past to the present and future. Oppressive medical devices present a moral aggregation problem. To remedy this problem, we suggest redundantly layered solutions that are coordinated to disrupt reciprocal causal connections between the attitudes, practices, and artifacts of oppressive systems.

Open-source FlexNIRS: A low-cost, wireless and wearable cerebral health tracker.

Currently, there is great interest in making neuroimaging widely accessible and thus expanding the sampling population for better understanding and preventing diseases. The use of wearable health devices has skyrocketed in recent years, allowing continuous assessment of physiological parameters in patients and research cohorts. While most health wearables monitor the heart, lungs and skeletal muscles, devices targeting the brain are currently lacking. To promote brain health in the general population, we developed a novel, low-cost wireless cerebral oximeter called FlexNIRS. The device has 4 LEDs and 3 photodiode detectors arranged in a symmetric geometry, which allows for a self-calibrated multi-distance method to recover cerebral hemoglobin oxygenation (SO2) at a rate of 100 Hz. The device is powered by a rechargeable battery and uses Bluetooth Low Energy (BLE) for wireless communication. We developed an Android application for portable data collection and real-time analysis and display. Characterization tests in phantoms and human participants show very low noise (noise-equivalent power <70 fW/√Hz) and robustness of SO2 quantification in vivo. The estimated cost is on the order of $50/unit for 1000 units, and our goal is to share the device with the research community following an open-source model. The low cost, ease-of-use, smart-phone readiness, accurate SO2 quantification, real time data quality feedback, and long battery life make prolonged monitoring feasible in low resource settings, including typically medically underserved communities, and enable new community and telehealth applications.

Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations With Clinical Outcomes.

OBJECTIVES: To assess disparities in hypoxemia detection by pulse oximetry across self-identified racial groups and associations with clinical outcomes. DESIGN: Observational cohort study from May 5, 2018, to December 31, 2020. SETTING: Three academic medical centers in the United States. PATIENTS: Adults greater than or equal to 18 years who self-identified as White, Black, Asian, or American Indian admitted to the ICU or undergoing surgery during inpatient hospitalization with simultaneous measurements of pulse oximetry-estimated oxygen saturation and arterial blood gas-derived oxygen saturation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Multivariable models were employed to assess the relationships between race, occult hypoxemia (i.e., arterial blood gas-derived oxygen saturation < 88% despite pulse oximetry-estimated oxygen saturation ≥ 92%), and clinical outcomes of hospital mortality and hospital-free days. One-hundred twenty-eight-thousand two-hundred eighty-five paired pulse oximetry-estimated oxygen saturation-arterial blood gas-derived oxygen saturation measurements were included from 26,603 patients. Pulse oximetry-estimated oxygen saturation on average overestimated arterial blood gas-derived oxygen saturation by 1.57% (1.54-1.61%). Black, Asian, and American Indian patients were more likely to experience occult hypoxemia during hospitalization (estimated probability 6.2% [5.1-7.6%], 6.6% [4.9-8.8%], and 6.6% [4.4-10.0%], respectively) compared with White patients (3.6% [3.4-3.8%]). Black patients had increased odds of occult hypoxemia compared with White patients after adjustment (odds ratio, 1.65; 1.28-2.14; p < 0.001). Differences in occult hypoxemia between Asian and American Indian patients compared with White patients were not significant after adjustment (odds ratio, 1.53; 0.95-2.47; p = 0.077 and odds ratio, 1.31; 0.80-2.16; p = 0.288, respectively). Occult hypoxemia was associated with increased odds of mortality in surgical (odds ratio, 2.96; 1.20-7.28; p = 0.019) and ICU patients (1.36; 1.03-1.80; p = 0.033). Occult hypoxemia was associated with fewer hospital-free days in surgical (-2.5 d [-3.9 to -1.2 d]; p < 0.001) but not ICU patients (0.4 d [-0.7 to 1.4 d]; p = 0.500). CONCLUSIONS: Occult hypoxemia is more common in Black patients compared with White patients and is associated with increased mortality, suggesting potentially important outcome implications for undetected hypoxemia. It is imperative to validate pulse oximetry with expanded racial inclusion.

The Dewey Monitor: Pulse Oximetry can Warn of Hypoxia in an Immersed Rebreather Diver in Multiple Scenarios.

Divers who wish to prolong their time underwater while carrying less equipment often use devices called rebreathers, which recycle the gas expired after each breath instead of discarding it as bubbles. However, rebreathers' need to replace oxygen used by breathing creates a failure mechanism that can and frequently does lead to hypoxia, loss of consciousness, and death. The purpose of this study was to determine whether a pulse oximeter could provide a useful amount of warning time to a diver with a rebreather after failure of the oxygen addition mechanism. Twenty-eight volunteer human subjects breathed on a mixed-gas rebreather in which the oxygen addition system had been disabled. The subjects were immersed in water in four separate environmental scenarios, including cold and warm water, and monitored using pulse oximeters placed at multiple locations. Pulse oximeters placed on the forehead and clipped on the nasal ala provided a mean of 32 s (±10 s SD) of warning time to divers with falling oxygen levels, prior to risk of loss of consciousness. These devices, if configured for underwater use, could provide a practical and inexpensive alarm system to warn of impending loss of consciousness in a manner that is redundant to the rebreather.

Remote monitoring in telehealth care delivery across the U.S. cystic fibrosis care network.

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.

Performance of popular pulse oximeters compared with simultaneous arterial oxygen saturation or clinical-grade pulse oximetry: a cross-sectional validation study in intensive care patients.

OBJECTIVES: To evaluate the performance of direct-to-consumer pulse oximeters under clinical conditions, with arterial blood gas measurement (SaO2) as reference standard. DESIGN: Cross-sectional, validation study. SETTING: Intensive care. PARTICIPANTS: Adult patients requiring SaO2-monitoring. INTERVENTIONS: The studied oximeters are top-selling in Europe/USA (AFAC FS10D, AGPTEK FS10C, ANAPULSE ANP 100, Cocobear, Contec CMS50D1, HYLOGY MD-H37, Mommed YM101, PRCMISEMED F4PRO, PULOX PO-200 and Zacurate Pro Series 500 DL). Directly after collection of a SaO2 blood sample, we obtained pulse oximeter readings (SpO2). SpO2-readings were performed in rotating order, blinded for SaO2 and completed <10 min after blood sample collection. OUTCOME MEASURES: Bias (SpO2-SaO2) mean, root mean square difference (ARMS), mean absolute error (MAE) and accuracy in identifying hypoxaemia (SaO2 ≤90%). As a clinical index test, we included a hospital-grade SpO2-monitor (Philips). RESULTS: In 35 consecutive patients, we obtained 2258 SpO2-readings and 234 SaO2-samples. Mean bias ranged from -0.6 to -4.8. None of the pulse oximeters met ARMS ≤3%, the requirement set by International Organisation for Standardisation (ISO)-standards and required for Food and Drug Administration (FDA) 501(k)-clearance. The MAE ranged from 2.3 to 5.1, and five out of ten pulse oximeters met the requirement of ≤3%. For hypoxaemia, negative predictive values were 98%-99%. Positive predictive values ranged from 11% to 30%. Highest accuracy (95% CI) was found for Contec CMS50D1; 91% (86-94) and Zacurate Pro Series 500 DL; 90% (85-94). The hospital-grade SpO2-monitor had an ARMS of 3.0% and MAE of 1.9, and an accuracy of 95% (91%-97%). CONCLUSION: Top-selling, direct-to-consumer pulse oximeters can accurately rule out hypoxaemia, but do not meet ISO-standards required for FDA-clearance.

Comparison of SpO2 and heart rate values on Apple Watch and conventional commercial oximeters devices in patients with lung disease.

Lung diseases have high mortality and morbidity, with an important impact on quality of life. Hypoxemic patients are advised to use oxygen therapy to prolong their survival, but high oxygen saturation (SpO2) levels can also have negative effects. Pulse oximeters are the most common way to assess oxygen levels and guide medical treatment. This study aims to assess whether wearable devices can provide precise SpO2 measurements when compared to commercial pulse oximeters. This is a cross-section study with 100 patients with chronic obstructive pulmonary disease and interstitial lung disease from an outpatient pneumology clinic. SpO2 and heart rate data were collected with an Apple Watch Series 6 (Apple) and compared to two commercial pulse oximeters. The Bland-Altman method and interclass correlation coefficient were used to compare their values. We observed strong positive correlations between the Apple Watch device and commercial oximeters when evaluating heart rate measurements (r = 0.995, p < 0.001) and oximetry measurements (r = 0.81, p < 0.001). There was no statistical difference in the evaluation of skin color, wrist circumference, presence of wrist hair, and enamel nail for SpO2 and heart rate measurements in Apple Watch or commercial oximeter devices (p > 0.05). Apple Watch 6 is a reliable way to obtain heart rate and SpO2 in patients with lung diseases in a controlled environment.

The Performance of Digital Monitoring Devices for Oxygen Saturation and Respiratory Rate in COPD: A Systematic Review.

Healthcare access and delivery for individuals with chronic obstructive pulmonary disease (COPD) who live in remote areas or who are susceptible to contracting communicable diseases, such as COVID-19, may be a challenge. Telehealth and remote monitoring devices can be used to overcome this issue. However, the accuracy of these devices must be ensured before forming healthcare decisions based on their outcomes. Therefore, a systematic review was performed to synthesize the evidence on the reliability, validity and responsiveness of digital devices used for tracking oxygen saturation (SpO2) and/or respiratory rate (RR) in individuals with COPD, in remote settings. Three electronic databases were searched: MEDLINE (1996 to October 8, 2020), EMBASE (1996 to October 8, 2020) and CINAHL (1998 to October 8, 2020). Studies were included if they aimed to evaluate one or more measurement properties of a digital device measuring SpO2 or RR in individuals with COPD. Six-hundred and twenty-five articles were identified and after screening, 7 studies matched the inclusion criteria; covering 11 devices measuring SpO2 and/or RR. Studies reported on the reliability (n = 1), convergent validity (n = 1), concurrent validity (n = 2) and predictive validity (n = 2) of SpO2 devices and on the convergent validity (n = 1), concurrent validity (n = 1) and predictive validity (n = 1) of RR devices. SpO2 and RR devices were valid when compared against other respiration monitoring devices but were not precise in predicting exacerbation events. More well-designed measurement studies are needed to make firm conclusions about the accuracy of such devices.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2021.1945021 .

Cost-Effectiveness of Vioptix versus Clinical Examination for Flap Monitoring of Autologous Free Tissue Breast Reconstruction.

BACKGROUND: Vioptix is a near-infrared spectroscopy tissue oximetry technology that allows for noninvasive monitoring of flap perfusion. Despite the reported benefits of Vioptix, the cost-effectiveness of this flap monitoring technology has not been compared to clinical examination alone. METHODS: A cost-effectiveness model, from the patient perspective, was constructed with two treatment arms: clinical examination versus clinical examination combined with Vioptix for flap monitoring after autologous, free flap breast reconstruction. Costs, utilities, and other model inputs were identified from the literature. One-way and probabilistic sensitivity analyses were performed. Gamma distributions were created for cost variables, and beta distributions were created for probability variables. An incremental cost-effectiveness ratio under $50,000 per quality-adjusted life-year (QALY) was considered cost-effective. All analyses were performed using TreeAge Pro (Williamstown, Mass.). RESULTS: Mean cost of autologous free tissue transfer breast reconstruction with clinical examination-based flap monitoring was found to be $37,561 with an effectiveness of 0.79, whereas the mean cost of clinical examination with Vioptix for flap monitoring was $39,361 with effectiveness of 0.82. This yielded an incremental cost-effectiveness ratio of $60,507 for clinical examination combined with Vioptix for flap monitoring. One-way sensitivity analysis revealed that clinical examination with Vioptix became cost-effective when the cost of Vioptix was less than $1487. Probabilistic sensitivity analysis found that clinical examination was cost-effective in 86.5 percent of cases. CONCLUSION: Although clinical examination combined with Vioptix is minimally more effective for flap monitoring after autologous, free flap breast reconstruction, clinical examination alone is the more cost-effective flap monitoring option.

Accuracy and Reliability of Pulse O2 Saturation Measured by a Wrist-worn Oximeter.

This study aims to evaluate the accuracy of the Garmin Forerunner 245 heart rate (HR) and pulse O2 saturation (SpO2) sensors compared with electrocardiogram and medical oximeter, from sea level to high altitude. Ten healthy subjects underwent five tests in normoxia and hypoxia (simulated altitudes from 3000 to 5500 m), consisting in a 5-min rest phase, followed by 5-min of mild exercise. Absolute error (±10 bpm for HR and ±3% for SpO2, around criterion) and intraclass correlations (ICC) were calculated. Error rates for HR remained under 10%, except at 3000 m, and ICCs evidenced a good reliability between Garmin and criterion. Overall SpO2 was higher than criterion (P<0.001) with a >50% error rate (>80% above 4800 m), and a poor reliability with criterion. The Garmin device displayed acceptable HR data at rest and exercise for all altitudes, but failed to provide trustworthy SpO2 values, especially at high altitude, where a pronounced arterial O2 desaturation could lead to acute mountain sickness in hypoxia-sensitive subjects, and its life-threatening complications; moreover, readings of overestimated SpO2 values might induce trekkers into further hazardous behavior by pursuing an ascent while being already at risk. Therefore, its use to assess SpO2 should be proscribed in altitude for acclimatization evaluation.

Monitoring Breast Reconstruction Flaps Using Near-Infrared Spectroscopy Tissue Oximetry.

Free flap reconstruction is a common procedure with success rates greater than 99%. However, vascular complications may occur, resulting in flap failure. For this reason, early detection of vascular compromise is crucial for flap salvage. Vascular complications may be detected early by monitoring tissue oximetry parameter changes using near-infrared spectroscopy (NIRS). This method of noninvasive monitoring can evaluate changes in flap oxygenation levels caused by arterial and venous thrombosis before surgical reexploration. The goal of this study was to assess the validity of using NIRS oximetry for monitoring free flaps. We conducted a prospective cohort observational study of 10 patients undergoing breast reconstruction. We used the INVOS 7100 cerebral oximetry monitoring system (Medtronic, Dublin, Ireland) to provide 24-hr continuous postoperative monitoring of flap perfusion and compared the data with clinical assessment findings. The median patient age was 57 years (range = 41-61 years). Patients underwent immediate breast reconstruction with deep inferior epigastric perforator (DIEP) flap surgery (n = 4), delayed reconstruction with DIEP flap surgery (n = 4), transverse upper gracilis flap surgery (n = 1), and latissimus dorsi flap with lipofilling (n = 1). We successfully monitored all 10 flaps for 24 hr postoperatively. The overall flap survival rate was 100%. Findings of clinical examination, Doppler studies, and surgical outcome were consistent with NIRS monitoring. In conclusion, NIRS tissue oximetry could potentially provide a noninvasive method for effective postoperative monitoring of free flaps.

Term Newborns with relatively low Tissue Oxygen Saturation Levels soon after Birth are predisposed to Neonatal Respiratory Disorders in Low-risk, Elective Cesarean Sections.

Background: Neonatal respiratory disorders, such as transient tachypnea of the newborn and respiratory distress syndrome, occur frequently after an elective cesarean delivery. Although conventional pulse oximetry is recommended for neonatal resuscitation, it often requires several minutes after birth to obtain a reliable signal. In a previous study, we used novel tissue oximetry equipment to detect fetal and neonatal early tissue oxygen saturation (StO2) before and immediately after vaginal delivery. Therefore, we hypothesized that low neonatal StO2 levels measured by tissue oximetry may lead to neonatal respiratory disorder after a scheduled cesarean delivery. Hence, this study aimed to evaluate the StO2 levels measured by tissue oximetry in neonates with or without a respiratory disorder subsequently diagnosed after an elective cesarean delivery. Materials and methods: We enrolled 78 pregnant Japanese women who underwent an elective cesarean section at ≥36 weeks' gestation. After combined spinal and epidural anesthesia were administered to the mother, fetal StO2 levels were measured by tissue oximetry using an examiner's finger-mounted sensor during a pelvic examination immediately before the cesarean section. We measured the neonatal StO2 levels at 1, 3, and 5 minutes after birth and retrospectively compared the fetal and neonatal StO2 levels with the incidence of subsequent diagnoses of neonatal respiratory disorders. Results: The data of StO2 levels in 35 neonates were collected. Seven neonates (respiratory disorder (RD) group) were subsequently diagnosed with respiratory disorders by neonatal medicine specialists, whereas the 28 remaining neonates (NR group) were not. The median fetal StO2 (interquartile range) of the RD and NR groups was 52.0% (41.8%-60.8%) and 42.5% (39.0%-52.5%), respectively (P = 0.12). The median neonatal StO2 (interquartile range) of the RD and NR groups at 1 minute after birth was 42.0% (39.0%-44.0%) and 46.0% (42.0%-49.0%), respectively (P = 0.091). At 3 minutes after birth, the median neonatal StO2 (interquartile range) of the RD and NR groups was 41.0% (39.0%-46.0%) and 47.0% (44.3%-53.5%), respectively (P = 0.004). Finally, at 5 minutes after birth, the median neonatal StO2 (interquartile range) of the RD and NR groups was 45.0% (44.0%-52.0%) and 54.0% (49.3%-57.0%), respectively (P = 0.007). Conclusions: The StO2 values in the RD group were lower than those in the NR group at 3 and 5 minutes after birth, suggesting that neonates with low StO2 levels soon after birth may be predisposed to clinically diagnosed neonatal respiratory disorders.