Nivolumab plus relatlimab in patients with previously treated microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer: the phase II CheckMate 142 study.

BACKGROUND: Programmed death-1 (PD-1) inhibitors, including nivolumab, have demonstrated long-term survival benefit in previously treated patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (CRC). PD-1 and lymphocyte-activation gene 3 (LAG-3) are distinct immune checkpoints that are often co-expressed on tumor-infiltrating lymphocytes and contribute to tumor-mediated T-cell dysfunction. Relatlimab is a LAG-3 inhibitor that has demonstrated efficacy in combination with nivolumab in patients with melanoma. Here, we present the results from patients with MSI-H/dMMR metastatic CRC treated with nivolumab plus relatlimab in the CheckMate 142 study. METHODS: In this open-label, phase II study, previously treated patients with MSI-H/dMMR metastatic CRC received nivolumab 240 mg plus relatlimab 160 mg intravenously every 2 weeks. The primary end point was investigator-assessed objective response rate (ORR). RESULTS: A total of 50 previously treated patients received nivolumab plus relatlimab. With median follow-up of 47.4 (range 43.9-49.2) months, investigator-assessed ORR was 50% (95% CI 36% to 65%) and disease control rate was 70% (95% CI 55% to 82%). The median time to response per investigator was 2.8 (range 1.3-33.1) months, and median duration of response was 42.7 (range 2.8-47.0+) months. The median progression-free survival per investigator was 27.5 (95% CI 5.3 to 43.7) months with a progression-free survival rate at 3 years of 38%, and median overall survival was not reached (95% CI 17.2 months to not estimable), with a 56% overall survival rate at 3 years. The most common any-grade treatment-related adverse events (TRAEs) were diarrhea (24%), asthenia (16%), and hypothyroidism (12%). Grade 3 or 4 TRAEs were reported in 14% of patients, and TRAEs of any grade leading to discontinuation were observed in 8% of patients. No treatment-related deaths were reported. CONCLUSIONS: Nivolumab plus relatlimab provided durable clinical benefit and was well tolerated in previously treated patients with MSI-H/dMMR metastatic CRC. TRIAL REGISTRATION NUMBER: NCT02060188.

A global dataset of diel activity patterns in insect communities.

Insect activity powers ecosystems and food production globally. Although insect activity is known to vary with the rise and setting of the sun, there is surprisingly limited empirical information on how insect abundance and richness varies across the 24-hour day-night (diel) cycle. Moreover, commonly used methods for sampling insects such as light traps do not provide suitable comparisons of community properties between diel periods. We present a dataset of 1512 observations of abundance and richness during diurnal and nocturnal periods in insect communities worldwide. The data were collected from 99 studies that systematically sampled insect communities during day and night, using sampling methods minimally influenced by diel variation, such as movement-based interception traps. Spanning six continents, 41 countries and 16 insect orders, the data can support investigations into the factors influencing insect diel preferences as well as the causes and consequences of temporal changes in insect biodiversity. The data also provides key baseline information on the diel activity patterns of insect communities for long-term ecological monitoring. These pursuits take on added significance considering contemporary 'insect declines' and increasing anthropogenic impacts on diurnal and nocturnal biodiversity.

Global meta-analysis reveals overall higher nocturnal than diurnal activity in insect communities.

Insects sustain key ecosystem functions, but how their activity varies across the day-night cycle and the underlying drivers are poorly understood. Although entomologists generally expect that more insects are active at night, this notion has not been tested with empirical data at the global scale. Here, we assemble 331 quantitative comparisons of the abundances of insects between day and night periods from 78 studies worldwide and use multi-level meta-analytical models to show that insect activity is on average 31.4% (CI: -6.3%-84.3%) higher at night than in the day. We reveal diel preferences of major insect taxa, and observe higher nocturnal activity in aquatic taxa than in terrestrial ones, as well as in warmer environments. In a separate analysis of the small subset of studies quantifying diel patterns in taxonomic richness (31 comparisons from 13 studies), we detect preliminary evidence of higher nocturnal richness in tropical than temperate communities. The higher overall (but variable) nocturnal activity in insect communities underscores the need to address threats such as light pollution and climate warming that may disproportionately impact nocturnal insects.

The role of victimisation and sleep quality in self-harm and depression among sexual minority adolescents. A prospective cohort study.

Sexual minority adolescents (SMA) have a disproportionately high prevalence of victimisation, self-harm, and depressed mood, relative to the general population. Yet, the contributing and mechanistic factors are unclear. We aim to explore the directional relationship between victimisation and self-harm and depressed mood, with poor sleep quality as a possible mediator. A secondary data analysis was conducted using a nationally representative birth cohort in the United Kingdom, where participants self-identified as sexual minority (N = 1922, aged 11-13, 67.1% female) and their parents completed questionnaires and interviews when the participants were aged 11, 14 and 17. Logistic and linear regression were used to test whether victimisation prospectively predicted self-harm and depressed mood with mediation analyses conducted to assess if sleep onset latency and nocturnal awakening mediated their relationships. After adjusting for demographic factors and baseline self-harm and depressed mood, victimisation at age 11 significantly predicted self-harm (OR = 1.40, p < .01) and depressed mood (B = 0.024, SE = 0.01, p < .05) at age 17. In the mediation analyses, frequent nocturnal awakening at age 14, but not sleep onset latency, significantly mediated the effect of victimisation at age 11 on self-harm (indirect effect B = 0.008, SE = 0.004, 95%CI = 0.001-0.017) and depressed mood (indirect effect B = 0.005, SE = 0.002 95%CI = 0.001-0.010) at age 17. Our findings supported that victimisation contributed to negative mental health among SMA. Poor sleep quality could be an indicator of maladjustment with victimisation, which further increased vulnerability to negative mental health. Victimisation and sleep quality could be important assessment targets in mental health campaign among sexual minority adolescents.

Effectiveness of population-based recovery actions for threatened southern mountain caribou.

Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective.

Leptanillavoldemort sp. nov., a gracile new species of the hypogaeic ant genus Leptanilla (Hymenoptera, Formicidae) from the Pilbara, with a key to Australian Leptanilla.

The genus Leptanilla Emery, 1870 of the family Formicidae, subfamily Leptanillinae, comprises miniscule, pale, blind ants that are rarely collected and poorly understood due to their hypogaeic (i.e. underground) lifestyles. Here we describe a new Leptanilla species from two workers collected via subterranean scraping in the arid Pilbara region of Western Australia. Leptanillavoldemortsp. nov. is the second leptanilline species documented in Australia after the elusive Leptanillaswani Wheeler, 1932. Workers of L.voldemortsp. nov. display a remarkably gracile morphology characterised by elongated legs, antennae, and mandibles, and they are easily differentiated from other Leptanilla species. We also provide new measurements for L.swani from two workers found proximally to the type locality of L.voldemortsp. nov. A key to the worker caste of Leptanilla species of the Australian continent is presented.

Applying the UTAUT2 framework to patients' attitudes toward healthcare task shifting with artificial intelligence.

BACKGROUND: Increasing patient loads, healthcare inflation and ageing population have put pressure on the healthcare system. Artificial intelligence and machine learning innovations can aid in task shifting to help healthcare systems remain efficient and cost effective. To gain an understanding of patients' acceptance toward such task shifting with the aid of AI, this study adapted the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2), looking at performance and effort expectancy, facilitating conditions, social influence, hedonic motivation and behavioural intention. METHODS: This was a cross-sectional study which took place between September 2021 to June 2022 at the National Heart Centre, Singapore. One hundred patients, aged ≥ 21 years with at least one heart failure symptom (pedal oedema, New York Heart Association II-III effort limitation, orthopnoea, breathlessness), who presented to the cardiac imaging laboratory for physician-ordered clinical echocardiogram, underwent both echocardiogram by skilled sonographers and the experience of echocardiogram by a novice guided by AI technologies. They were then given a survey which looked at the above-mentioned constructs using the UTAUT2 framework. RESULTS: Significant, direct, and positive effects of all constructs on the behavioral intention of accepting the AI-novice combination were found. Facilitating conditions, hedonic motivation and performance expectancy were the top 3 constructs. The analysis of the moderating variables, age, gender and education levels, found no impact on behavioral intention. CONCLUSIONS: These results are important for stakeholders and changemakers such as policymakers, governments, physicians, and insurance companies, as they design adoption strategies to ensure successful patient engagement by focusing on factors affecting the facilitating conditions, hedonic motivation and performance expectancy for AI technologies used in healthcare task shifting.

Systematic Review of Preoperative Prognostic Biomarkers in Perihilar Cholangiocarcinoma.

Perihilar cholangiocarcinoma (pCCA) is an uncommon malignancy with generally poor prognosis. Surgery is the primary curative treatment; however, the perioperative mortality and morbidity rates are high, with a low 5-year survival rate. Use of preoperative prognostic biomarkers to predict survival outcomes after surgery for pCCA are not well-established currently. This systematic review aimed to identify and summarise preoperative biomarkers associated with survival in pCCA, thereby potentially improving treatment decision-making. The Embase, Medline, and Cochrane databases were searched, and a systematic review was performed using the PRISMA guidelines. English-language studies examining the association between serum and/or tissue-derived biomarkers in pCCA and overall and/or disease-free survival were included. Our systematic review identified 64 biomarkers across 48 relevant studies. Raised serum CA19-9, bilirubin, CEA, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and tumour MMP9, and low serum albumin were most associated with poorer survival; however, the cutoff values used widely varied. Several promising molecular markers with prognostic significance were also identified, including tumour HMGA2, MUC5AC/6, IDH1, PIWIL2, and DNA index. In conclusion, several biomarkers have been identified in serum and tumour specimens that prognosticate overall and disease-free survival after pCCA resection. These, however, require external validation in large cohort studies and/or in preoperatively obtained specimens, especially tissue biopsy, to recommend their use.

The floating hip injury: a descriptive study and case-control analysis.

PURPOSE: A "floating hip" (FH) injury is a rare injury describing the simultaneous ipsilateral fracture of the femur and pelvis or acetabulum (P/A). We describe our experience with patients presenting with FH injuries and compare them to controls with similar P/A fractures but without femoral involvement. METHODS: Medical records and radiographs of FH patients and controls presenting to our tertiary centre between 2015 and 2020 were reviewed. Follow-up data from outpatient clinical records were also extracted. The control group were extensively matched by age, sex, body mass index, fracture classification and energy of injury. RESULTS: From 1392 recorded P/A fractures, 42 FH cases were identified (average age 39 years, 78.6% males). The most common femoral fracture was the midshaft (35.7%), followed by the neck of femur (26.2%). 90.5% of FH injuries were due to high-energy mechanisms. 64.3% of P/A fractures, and 100% of femoral fractures were managed surgically. Compared to controls, FH cases were more likely to have additional orthopaedic injuries (73.8% vs. 40.5%, p = 0.002), more total theatre admissions (mean 2.5 vs. 1.19, p < 0.001), longer hospital stays (28.3 vs. 14.9 days, p = 0.02), and a higher rates of post-op complications (53.8% vs. 20%, p = 0.025). CONCLUSIONS: We report differences in the presentation, management, and outcomes of FH injuries versus controls, even after extensive matching for confounders. These differences may inform future treatment strategies for the FH injury.

Sleep and Socioemotional Outcomes Among Sexual and Gender Minority Adolescents: A Longitudinal Study.

Sexual and gender minority adolescents face specific stressors associated with their minority status, leading to compromised socioemotional outcomes and sleep. Sleep patterns have, in turn, been found to predict socioemotional outcomes. As such, we aimed to investigate whether healthy sleep patterns prospectively predicted socioemotional outcomes, and whether associations varied as a function of sexual and gender minority status. We conducted a secondary data analysis among adolescents at age 14 to 17, from a nationally representative prospective cohort in the United Kingdom (N = 8923, mean age = 13.8), with 7021 cisgender heterosexual, 1801 sexual minority, and 101 gender minority adolescents. Indicators of socioemotional outcomes included self-esteem, emotional well-being, peer relationships, and relationship with parents. The results showed that gender minority adolescents reported the worst sleep patterns and socioemotional outcomes, followed by sexual minority and cisgender heterosexual adolescents. Results from multi-group path analyses showed that emotional well-being, self-esteem, and peer relationships at age 17 were prospectively predicted by sleep patterns and the associations were moderated by sexual and gender minority status. Influence of sleep patterns, particularly sleep initiation problems and frequent awakening, on socioemotional outcomes was greater among gender minority adolescents, when compared to cisgender heterosexual adolescents. In conclusion, positive socioemotional outcomes were predicted by healthy sleep patterns. The potential role of sleep health in optimizing socioemotional outcomes among sexual and gender minority adolescents might warrant further investigation in prevention or intervention studies.

Real-World Outcomes of FLOT versus CROSS Regimens for Patients with Oesophagogastric Cancers.

Introduction: Treatment of oesophageal (OC), gastro-oesophageal junction (GOJ), and gastric cancer (GC) includes either neoadjuvant Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) for OC or GOJ or perioperative 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) for OC, GOJ, and GC adenocarcinomas. This study aims to describe the real-world outcomes of patients with GC, GOJ, and OC treated with FLOT or CROSS and identify variables associated with efficacy through exploratory analysis. We also aimed to evaluate the comparison of FLOT and CROSS for the treatment of OC and GOJ adenocarcinomas. Methods: This is a retrospective observational study of patients with locally advanced OC, GOJ, or GC treated with FLOT or CROSS between January 2015 and June 2021 in 5 cancer centres across Sydney, Australia. Long-rank test was used to compare survival estimated between subgroups. Hazard ratios for univariate and multivariate analyses were estimated with Cox proportional regression. Results: The study included 168 patients. The 24-month relapse-free survival (RFS) and overall survival (OS) for FLOT were 59% and 69%, respectively. The median RFS was 29.6 months and median OS was not reached. For CROSS, the 24-month RFS and OS were 55% and 63% with a median RFS and OS of 28.5 and 40.2 months, respectively. There was no difference in OS and RFS between the treatments. FLOT was less tolerable than CROSS with more dose reductions, treatment discontinuation, and clinically relevant grade 3 and 4 toxicity. Neutrophil lymphocyte ratio was associated with survival for both treatments. Conclusion: Similar efficacy outcomes were seen in this real-world population compared to the clinical trials for FLOT and CROSS.

Nurse Care Management for Opioid Use Disorder Treatment: The PROUD Cluster Randomized Clinical Trial.

Importance: Few primary care (PC) practices treat patients with medications for opioid use disorder (OUD) despite availability of effective treatments. Objective: To assess whether implementation of the Massachusetts model of nurse care management for OUD in PC increases OUD treatment with buprenorphine or extended-release injectable naltrexone and secondarily decreases acute care utilization. Design, Setting, and Participants: The Primary Care Opioid Use Disorders Treatment (PROUD) trial was a mixed-methods, implementation-effectiveness cluster randomized clinical trial conducted in 6 diverse health systems across 5 US states (New York, Florida, Michigan, Texas, and Washington). Two PC clinics in each system were randomized to intervention or usual care (UC) stratified by system (5 systems were notified on February 28, 2018, and 1 system with delayed data use agreement on August 31, 2018). Data were obtained from electronic health records and insurance claims. An implementation monitoring team collected qualitative data. Primary care patients were included if they were 16 to 90 years old and visited a participating clinic from up to 3 years before a system's randomization date through 2 years after. Intervention: The PROUD intervention included 3 components: (1) salary for a full-time OUD nurse care manager; (2) training and technical assistance for nurse care managers; and (3) 3 or more PC clinicians agreeing to prescribe buprenorphine. Main Outcomes and Measures: The primary outcome was a clinic-level measure of patient-years of OUD treatment (buprenorphine or extended-release injectable naltrexone) per 10 000 PC patients during the 2 years postrandomization (follow-up). The secondary outcome, among patients with OUD prerandomization, was a patient-level measure of the number of days of acute care utilization during follow-up. Results: During the baseline period, a total of 130 623 patients were seen in intervention clinics (mean [SD] age, 48.6 [17.7] years; 59.7% female), and 159 459 patients were seen in UC clinics (mean [SD] age, 47.2 [17.5] years; 63.0% female). Intervention clinics provided 8.2 (95% CI, 5.4-∞) more patient-years of OUD treatment per 10 000 PC patients compared with UC clinics (P = .002). Most of the benefit accrued in 2 health systems and in patients new to clinics (5.8 [95% CI, 1.3-∞] more patient-years) or newly treated for OUD postrandomization (8.3 [95% CI, 4.3-∞] more patient-years). Qualitative data indicated that keys to successful implementation included broad commitment to treat OUD in PC from system leaders and PC teams, full financial coverage for OUD treatment, and straightforward pathways for patients to access nurse care managers. Acute care utilization did not differ between intervention and UC clinics (relative rate, 1.16; 95% CI, 0.47-2.92; P = .70). Conclusions and Relevance: The PROUD cluster randomized clinical trial intervention meaningfully increased PC OUD treatment, albeit unevenly across health systems; however, it did not decrease acute care utilization among patients with OUD. Trial Registration: ClinicalTrials.gov Identifier: NCT03407638.

Optical Coherence Tomography Angiography in Retinal Vascular Disorders.

Traditionally, abnormalities of the retinal vasculature and perfusion in retinal vascular disorders, such as diabetic retinopathy and retinal vascular occlusions, have been visualized with dye-based fluorescein angiography (FA). Optical coherence tomography angiography (OCTA) is a newer, alternative modality for imaging the retinal vasculature, which has some advantages over FA, such as its dye-free, non-invasive nature, and depth resolution. The depth resolution of OCTA allows for characterization of the retinal microvasculature in distinct anatomic layers, and commercial OCTA platforms also provide automated quantitative vascular and perfusion metrics. Quantitative and qualitative OCTA analysis in various retinal vascular disorders has facilitated the detection of pre-clinical vascular changes, greater understanding of known clinical signs, and the development of imaging biomarkers to prognosticate and guide treatment. With further technological improvements, such as a greater field of view and better image quality processing algorithms, it is likely that OCTA will play an integral role in the study and management of retinal vascular disorders. Artificial intelligence methods-in particular, deep learning-show promise in refining the insights to be gained from the use of OCTA in retinal vascular disorders. This review aims to summarize the current literature on this imaging modality in relation to common retinal vascular disorders.

Haematological and nutritional prognostic biomarkers for patients receiving CROSS or FLOT.

Background: Neoadjuvant carboplatin and paclitaxel with radiotherapy (CROSS) and perioperative docetaxel, oxaliplatin, calcium folinate and fluorouracil (FLOT) are widely used for gastric (GC), gastro-oesophageal junction (GOJ) and oesophageal cancers (OC). Prognostic and predictive markers for response and survival outcomes are lacking. This study evaluates dynamic neutrophil-lymphocyte ratios (NLR), platelet-lymphocyte ratios (PLR), albumin and body mass index (BMI) as predictors of survival, response and toxicity. Methods: This multi-centre retrospective observational study across 5 Sydney hospitals included patients receiving CROSS or FLOT from 2015 to 2021. Haematological results and BMI were recorded at baseline and pre-operatively, and after adjuvant treatment for FLOT. Toxicities were also recorded. An NLR ≥2 and PLR ≥200 was used to stratify patients. Univariate and multivariate analyses were performed to determine predictors of overall survival (OS), disease free survival (DFS), rates of pathological complete response (pCR) and toxicity. Results: One hundred sixty-eight patients were included (95 FLOT, 73 FLOT). A baseline NLR ≥2 was predictive for worse DFS (HR 2.78, 95% CI: 1.41-5.50, P<0.01) and OS (HR 2.90, 95% CI: 1.48-5.67, P<0.01). Sustained elevation in NLR was predictive for DFS (HR 1.54, 95% CI: 1.08-2.17, P=0.01) and OS (HR 1.65, 95% CI: 1.17-2.33, P<0.01). An NLR ≥2 correlated with worse pCR rates (16% for NLR ≥2, 48% for NLR <2, P=0.04). A baseline serum albumin <33 was predictive of worse DFS and OS with a HR of 6.17 (P=0.01) and 4.66 (P=0.01) respectively. Baseline PLR, BMI, and dynamic changes in these markers were not associated with DFS, OS or pCR rates. There was no association of the aforementioned variables with toxicity. Conclusions: This demonstrates that a high inflammatory state represented by an NLR ≥2, both at baseline and sustained, is prognostic and predictive of response in patients receiving FLOT or CROSS. Baseline hypoalbuminaemia is predictive of poorer outcomes.

New Concepts for the Diagnosis of Polypoidal Choroidal Vasculopathy.

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular age-related macular degeneration (nAMD) that is characterized by a branching neovascular network and polypoidal lesions. It is important to differentiate PCV from typical nAMD as there are differences in treatment response between subtypes. Indocyanine green angiography (ICGA) is the gold standard for diagnosing PCV; however, ICGA is an invasive detection method and impractical for extensive use for regular long-term monitoring. In addition, access to ICGA may be limited in some settings. The purpose of this review is to summarize the utilization of multimodal imaging modalities (color fundus photography, optical coherence tomography (OCT), OCT angiography (OCTA), and fundus autofluorescence (FAF)) in differentiating PCV from typical nAMD and predicting disease activity and prognosis. In particular, OCT shows tremendous potential in diagnosing PCV. Characteristics such as subretinal pigment epithelium (RPE) ring-like lesion, en face OCT-complex RPE elevation, and sharp-peaked pigment epithelial detachment provide high sensitivity and specificity for differentiating PCV from nAMD. With the use of more practical, non-ICGA imaging modalities, the diagnosis of PCV can be more easily made and treatment tailored as necessary for optimal outcomes.

Repair of complex ovine segmental mandibulectomy utilizing customized tissue engineered bony flaps.

Craniofacial defects require a treatment approach that provides both robust tissues to withstand the forces of mastication and high geometric fidelity that allows restoration of facial architecture. When the surrounding soft tissue is compromised either through lack of quantity (insufficient soft tissue to enclose a graft) or quality (insufficient vascularity or inducible cells), a vascularized construct is needed for reconstruction. Tissue engineering using customized 3D printed bioreactors enables the generation of mechanically robust, vascularized bony tissues of the desired geometry. While this approach has been shown to be effective when utilized for reconstruction of non-load bearing ovine angular defects and partial segmental defects, the two-stage approach to mandibular reconstruction requires testing in a large, load-bearing defect. In this study, 5 sheep underwent bioreactor implantation and the creation of a load-bearing mandibular defect. Two bioreactor geometries were tested: a larger complex bioreactor with a central groove, and a smaller rectangular bioreactor that were filled with a mix of xenograft and autograft (initial bone volume/total volume BV/TV of 31.8 ± 1.6%). At transfer, the tissues generated within large and small bioreactors were composed of a mix of lamellar and woven bone and had BV/TV of 55.3 ± 2.6% and 59.2 ± 6.3%, respectively. After transfer of the large bioreactors to the mandibular defect, the bioreactor tissues continued to remodel, reaching a final BV/TV of 64.5 ± 6.2%. Despite recalcitrant infections, viable osteoblasts were seen within the transferred tissues to the mandibular site at the end of the study, suggesting that a vascularized customized bony flap is a potentially effective reconstructive strategy when combined with an optimal stabilization strategy and local antibiotic delivery prior to development of a deep-seated infection.

Applied machine learning for blood pressure estimation using a small, real-world electrocardiogram and photoplethysmogram dataset.

Applying machine learning techniques to electrocardiography and photoplethysmography signals and their multivariate-derived waveforms is an ongoing effort to estimate non-occlusive blood pressure. Unfortunately, real ambulatory electrocardiography and photoplethysmography waveforms are inevitably affected by motion and noise artifacts, so established machine learning architectures perform poorly when trained on data of the Multiparameter Intelligent Monitoring in Intensive Care II type, a publicly available ICU database. Our study addresses this problem by applying four well-established machine learning methods, i.e., random forest regression, support vector regression, Adaboost regression and artificial neural networks, to a small, self-sampled electrocardiography-photoplethysmography dataset (n = 54) to improve the robustness of machine learning to real-world BP estimates. We evaluated the performance using a selection of optimal feature morphologies of waveforms by using pulse arrival time, morphological and frequency photoplethysmography parameters and heart rate variability as characterization data. On the basis of the root mean square error and mean absolute error, our study showed that support vector regression gave the best performance for blood pressure estimation from noisy data, achieving an mean absolute error of 6.97 mmHg, which meets the level C criteria set by the British Hypertension Society. We demonstrate that ambulatory electrocardiography- photoplethysmography signals acquired by mobile discrete devices can be used to estimate blood pressure.