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James Mutinda

and 2 more

Sentiment analysis of social media posts and texts can provide information and knowledge that is applicable in social settings, business intelligence, evaluation of citizens’ opinions in governance and mood triggered devices in Internet of Things. Feature extraction and selection is a key determinant of accuracy and computational cost of machine learning models for such analysis. Most feature extraction and selection techniques utilize bag of words such as N-grams and frequency-based algorithms especially Term Frequency-Inverse document frequency (TF-IDF). However, these approaches suffer shortcomings such as; they do not consider relationships between words, they ignore words’ characteristics and they suffer high feature dimensionality. In this paper we propose and evaluate an approach that utilizes a fixed hybrid N-gram window for feature extraction and Minimum Redundancy Maximum Relevance feature selection for sentence level sentiment analysis. The approach improves the existing feature extraction techniques specifically the N-gram by generating a tri-gram vector from words, Part of speech tags and word semantic orientation. The N-gram vector is extracted by employing a static 3-gram window identified by a lexicon where a sentiment word appears in a sentence. A blend of the words, POS tags and the sentiment orientations of the 3N-gram are used to build the feature vector. The optimal features from the vector are then selected using Minimum Redundancy Maximum Relevance (MR2) algorithm. Experiments were carried out with a publicly available yelp tweets dataset to evaluate the performance of four supervised machine learning classifiers (Naïve Bayes, K-Nearest Neighbor, Decision Tree and Support Vector Machines) when augmented with the proposed model. The results showed that the proposed model had the highest accuracy (86.85%), recall (86.85%) and precision (86.96%).

Jianhua Miao

and 12 more

Abstract:Sophora tonkinensis (shandougen) is a woody leguminous plant widely known for its medicinal values in China. The genome of various legumes utilized as reference genetic maps for pseudomolecule assembly have been published. However, the genome of Sophora has not been mapped. In this study, we reported a chromosomal scale draft genome of S. tonkinensis assembled using PacBio single-molecule real-time sequencing reads and Hi-C technique. A high-quality draft S. tonkinensis genome of 899Mb in size was obtained, which was larger than those of some other leguminous genome, and the BUSCO analysis reviewed 95.9% completeness of the genome. We annotated 78.3% of the genome as repeat elements and transposable elements occupied 73%. A total of 36,410 protein-coding genes were identified in the S. tonkinensis genome. The comparative analysis on genome size and repetitive sequences of S. tonkinensis and four other legumes (Lupinus albus, Lupinus angustifolius, Glycyrrhiza uralensis and Medicago truncatula) revealed that the transposable elements (TEs) in S. tonkinensis were inserted after the whole genome duplication and after differentiation with other legumes. It can be speculated that the size of the S. tonkinensis genome may be related to the repetitive sequence insertion. We also analyzed matrine and flavonoids which are important compounds in S. tonkinensis. We further analyzed lignin and Nitrogen-fixing gene which plays an important role in the adaptation of S. tonkinensis to the environment. In conclusion, the high-quality genome of S. tonkinensis obtained in this study laid the foundation for genetic and molecular biology studies of legumes.

Ruiling Xu

and 4 more

OBJECTIVE Asymptomatic carriage of COVID-19 in pregnant women has been reported. We sought to ascertain the impact of high quality rapid PCR testing for COVID-19 in an unselected cohort of pregnant women attending our maternity unit. DESIGN Retrospective cohort analysis SETTING Cambridge, East of England POPULATION All pregnant women who were admitted to Rosie maternity unit over a 4-week period (May to June 2020) METHODS Pregnant women were screened for COVID-19 using nasopharyngeal and oropharyngeal swabs on admission. Samples were analysed using the SAMBA-II RT-PCR machine. Symptoms were defined as cough and/or fever that could not be attributed to an obstetric cause. RESULTS NP and OP swabs were obtained from 457/465 women during the study period (98%). The median turnaround time for results was 5.3 hours (IQR 2.6-8.9). 92% of results were returned within 24 hours. In our cohort, only one woman tested positive, giving a screen positive rate of 0.2% (1/457). One woman who tested negative developed a fever postnatally following discharge but was lost to follow-up. There was no correlation between asymptomatic carriage and regional prevalence of COVID-19. CONCLUSIONS Testing using the SAMBA-II machine was acceptable to the vast majority of pregnant women requiring admission and had a low turnaround time. Asymptomatic carriage is low, but not correlated to community prevalence rates. Screening pregnant women on admission will remain an important component in order to minimise nosocomial infection and spread within healthcare workers as COVID-19 rates increase in the UK.
ABSTRACTMany articles clearly state that the birth rate is expected to drop under the covid-19 pandemic. Based on the past study, after the Spanish flu pandemic there was a surge called, Spanish flu baby boom. The strength of economy after the pandemic determined the size of the surge.Meredith Wadman wrote a short article on the birth rate of the covid-19 pandemic1. Döring described a commentary article on how the covid-19 pandemic affecting our sexualities2. Miriam also mentioned how the covid-19 pandemic is affecting birthrates worldwide3. Brookings institution predicts the followings4:the covid-19 episode will likely lead to a large, lasting baby bust,the pandemic has thrust the country into an economic recession,economic reasoning and past evidence suggest that this will lead people to have fewer children,the decline in births could be on the order of 300,000 to 500,000 fewer births next year.All articles1,2,3,4clearly state that the birth rate is expected to drop under the covid-19 pandemic.We can sometimes learn from the past study. According to CDC on the Spanish flu pandemic (H1N1 virus), lasting from February 1918 to April 1920, it infected 500 million people–about a third of the world’s population at the time5. Over three waves of infections, the Spanish flu killed at least 50 million worldwide5. Based on the past study of the Spanish influenza pandemic, the birth rate was dropped during the pandemic6,7,8. After the pandemic there was a surge called, Spanish flu baby boom6,7,8. However, we don’t know when the covid-19 pandemic will be ended. The world population in 1918 was less than 2 billion while it is now nearly 7.8 billion. By the summer of 1919, the flu pandemic in US came to an end, as those that were infected either died or developed immunity9. We know the fact that the U.S. fertility rate is proportional to the strength of economy which can be generalized worldwide10. Based on the fact, the birth rate may be strongly influenced by the strength of economy after the pandemic. In other words, it will surge after the pandemic where the birth rate spike may be depending on the state of economy.This research did not receive any specific funding. The authors declare no conflict of interest.References:Meredith Wadman, COVID-19 unlikely to cause birth defects, but doctors await fall births, Science 07 Aug 2020: Vol. 369, Issue 6504, pp. 607Döring, N. How Is the COVID-19 Pandemic Affecting Our Sexualities? An Overview of the Current Media Narratives and Research Hypotheses.Arch Sex Behav (2020).https://doi.org/10.1007/s10508-020-01790-zMiriam Berger, Coronavirus baby boom or bust? How the pandemic is affecting birthrates worldwide, the Washington Post, July 15, 2020.https://www.washingtonpost.com/world/2020/07/15/coronavirus-baby-boom-or-bust-how-pandemic-is-affecting-birthrates-worldwide/4. Melissa S. Kearney and Phillip B. Levine, “Half a million fewer children? The coming COVID baby bust”, June 15 2020.https://www.brookings.edu/research/half-a-million-fewer-children-the-coming-covid-baby-bust/5.https://www.cdc.gov/flu/pandemic-resources/1918-pandemic-h1n1.html6. https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/livebirths/articles/trendsinbirthsanddeathsoverthelastcentury/2015-07-157. Mamelund, Svenn-Erik. “Can the Spanish Influenza Pandemic of 1918 Explain the Baby Boom of 1920 in Neutral Norway?” Population (English Edition, 2002-) , vol. 59, no. 2, 2004, pp. 229–260.JSTOR ,www.jstor.org/stable/3654904.8. Siddharth Chandra et al., The 1918 influenza pandemic and subsequent birth deficit in Japan, DEMOGRAPHIC RESEARCH, vol.33, 11, pp. 313−326, 6 AUGUST 2015.9. Spanish flu, https://www.history.com/topics/world-war-i/1918-flu-pandemic10. Mark Mather, The Decline in U.S. Fertility, July 18, 2012. https://www.prb.org/us-fertility/

BURCU GÜVEN

and 3 more

Background: Discrimination of inflammatory bowel diseases (IBD) and other gastrointestinal diseases in pediatric patients is highly important and the definitive diagnosis of IBD is established by endoscopic examination. the use of noninvasive methods (clinical symptoms and laboratory tests) allows an early and accurate referral of patients from first step health centers to advanced health centers. In the present study, we aimed to investigate the effectiveness of fecal calprotectin (FC) in the discrimination of IBD and other gastrointestinal diseases in children. Methods: The retrospective study included the patients that underwent FC testing and colonoscopy. Demographic characteristics, Alarm symptoms (AS), and abnormal laboratory findings (ALF) were recorded for each patient. A negative calprotectin result was considered to be less than 50 μg/g, and a second cutoff value for FC was accepted as 150 µg/g. Definitive diagnosis was established by colonoscopy in each patient. Results: The study included 88 consecutive patients (mean age, 10.2 ± 6.1 years; 51.1% female). Of these, 20 (22.7%) patients were diagnosed with IBD. No significant difference was found between IBD and non-IBD patients with regard to AS except for involuntary weight loss (p=<0.001). The incidence of increased CRP and hypoalbuminemia was significantly higher in IBD patients (p=0.002 and p=0.026, respectively). AS combined with ALF and FC >150 µg/g had the highest specificity (95.12%). Conclusions: Although primary care clinicians often use AS and laboratory parameters in the discrimination of IBD and non-IBD diseases, FC was found to have a relatively higher diagnostic value.

Shengsheng Han

and 4 more

Studying soil water dynamics and water balance on coral islands is important to utilize and manage the limited freshwater resources of these islands. In this study, we investigated the soil water dynamics of Zhaoshu Island, Xisha Archipelago, using observed data and the Richards equation and analyzed the water balance of this island from October 2018 to September 2019. We found a dry soil layer at depths between 40 cm and 160 cm of the soil profile from November 2018 to April 2019 (dry season) which prevented the exchange of water between upper soil layers and groundwater. Therefore, the vegetation developed deep roots to take up water from the groundwater. Precipitation is the only source of the freshwater, while approximately 38% of the precipitation infiltrated into the groundwater, 22% of the precipitation was taken up by vegetation, and 39% of the precipitation evaporated from the land surface during the entire observed year. In the dry season, evapotranspiration (ETa) was only 44 mm/month, which was 94% greater than the amount of precipitation, and approximately 14 mm/month of water was taken up from the groundwater by plants. However, in wet season, infiltration dominated the processes of soil water movement. Approximately 56% of the precipitation infiltrated into the groundwater and 37% of the precipitation was consumed by ETa. This study can help us to better understand the process of water movement on coral islands and provide references for further management to protect coral island ecology.

Daniel Demers

and 2 more

Hande Nur Öncü

and 2 more

Objective: The aim of this study was to evaluate the effect of using uterine fundal pressure during the second stage of delivery on obstetric anal sphincter injury (OASI), among primiparous women using three-dimensional transperineal ultrasonography. Design: Case control study Setting: Tertiary Urogynecology Unit Population: Nulliparous women with term, singleton, cephalic presentation gestation delivered with fundal pressure in second stage of labour. Main Outcome Measure: Complete, incomplete IAS and EAS defect in transperineal tomographic ultrasound imaging Method: A total of 73 women who had their first vaginal birth were included in the study, 37 of them applied fundal pressure and 36 of them delivered spontaneously without fundal pressure. Tomographic ultrasound imaging with 3D transperineal assessment was performed within 48 h of delivery, IAS and EAS defect were determined. Results: Five (13.5%) women in the fundal pressure group, 7 (20%) women in the control group had complete EAS (p = 0.4). Complete IAS was observed in 1 (2.7%) women in the fundal pressure group and 2 (5.7%) women in the control group (p = 0.5). Half-moon sign was observed in 1 woman in both groups (p = 0.9). The rate of other signs were similar in both groups. Multivariate regression models revealed that none of, age, episiotomy, length of second stage of labour, fundal pressure application status and number were independent predictor of complete IAS or EAS defect. Conclusions: Fundal pressure during the second stage of delivery is not cause increase in rate of OASI detected with ultrasonography.

Huihui Chen

and 3 more

Study Objective: To examine the correlation between the occurrence of adenomyosis and the outcome of vaginal repair of cesarean scar defects (CSD). Design: A retrospective observational cohort study. Setting: University hospital. Patients: A total of 278 women with CSD were enrolled at the Shanghai First Maternity & Infant Hospital between January 2013 and August 2017. Interventions: Vaginal excision and suture of CSD. Measures and Main Results: According to preoperative magnetic resonance imaging (MRI) findings, patients were divided into two groups, the adenomyosis group (group A) and the non-adenomyosis group (group B). For group A patients, the mean duration of menstruation at 3- and 6-months follow-up was shorter and the TRM at the median-month follow-up was significantly thinner than those in group B patients (p < 0.05). There were more patients with class-A healing in group B compared with group A (44.7% vs 30.0%; p < 0.05). Furthermore, 59.3% (32/54) of women tried to conceive after vaginal repair. The pregnancy rates of women with and without adenomyosis were 66.7% (8/12) and 61.9% (26/42), respectively. The duration of menstruation decreased significantly from 13.4 ± 3.3 days to 7.6 ± 2.3 days after vaginal repair in 25 patients (p < 0.001). The TRM increased significantly from 2.3 ± 0.8 mm to 7.6 ± 2.9 mm after vaginal repair (p < 0.001). Conclusion: Vaginal repair reduced postmenstrual spotting and improve fertility in patients with CSD. Adenomyosis might be an adverse factor in the repair of uterine incisions.

Qiwei Guo

and 8 more

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Matthew Sussman

and 9 more

The recognition of fibrinolysis phenotypes in trauma patients has led to a reevaluation of antifibrinolytic therapy (AF). Many cardiac patients also receive AF, however the distribution of fibrinolytic phenotypes in that population is unknown. The purpose of this study was to fill that gap. Methods: Data were retrospectively reviewed from 78 cardiac surgery patients. Phenotypes were defined as hypofibrinolytic (LY30 <0.8%), physiologic (LY30 0.8-3.0%) and hyperfibrinolytic (LY30 >3%). Continuous variables were expressed as M ± SD or median (interquartile range). Results: The study population was 65±10 yrs old, 74% male, average body mass index of 29±5 kg/m2. Fibrinolytic phenotypes were distributed as physiologic=45%, hypo=32% and hyper = 23%. There was no obvious effect of age, gender, race, or ethnicity on the distribution of fibrinolysis phenotypes; 47% received AF. The time with chest tube during post-operative recovery was longer in those who received AF (4[3,5] days) vs no AF (3[2,4] days), P=0.037). All cause morbidity occurred in 51% of patients who received AF vs 25% with no AF (p=0.017). However, with AF vs no AF, apparent differences in median chest tube output (1379 vs 820ml, p=0.075), hospital LOS (13 vs 10 days, P=0.873), estimated blood loss (1100 vs 775 ml, P=0.127), units of transfused RBCs (4 vs 2], P=0.152) or all-cause mortality (5.4% [2/37] vs 10% [4/41], P=0.518) were not statistically significant. Conclusion: This is the first description of three distinctly different fibrinolytic phenotypes in cardiac surgery patients. In this population, the use of AF was associated with increased morbidity.

Arushi Singh

and 6 more

Background: Ibrutinib is associated with atrial fibrillation (AF), though echocardiographic predictors of AF have not been studied in this population. We sought to determine whether left atrial (LA) strain on transthoracic echocardiography could identify patients at risk for developing ibrutinib-related atrial fibrillation (IRAF). Methods: We performed a retrospective review of 66 patients who had an echocardiogram prior to ibrutinib treatment. LA strain was measured with TOMTEC Imaging Systems, obtaining peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS) on 4-chamber and 2-chamber views. Statistical analysis was performed with Chi-square analysis, T-test, or binomial regression analysis, with a p-value < 0.05 considered statistically significant. Results: Twenty-two patients developed IRAF (33%). Age at initiation of ibrutinib was significantly associated with IRAF (65.1 years vs. 74.1 years, p = 0.002). Mean ibrutinib dose was lower among patients who developed IRAF (388.2 ± 121.7 vs. 448.6 ± 88.4, p = 0.025). E/e’ was significantly higher among patients who developed IRAF (11.5 vs. 9.3, p = 0.04). PALS was significantly lower in patients who developed AF (30.3% vs. 36.3%, p = 0.01). On multivariate regression analysis, age, PALS and PACS were significantly associated with IRAF. On multivariate regression analysis, only PACS remained significantly associated with IRAF while accounting for age. Conclusions: Age, ibrutinib dose, E/e’, and PALS on pre-treatment echocardiogram were significantly associated with development of IRAF. On multivariate regression analyses, age, PALS and PACS remained significantly associated with IRAF. Impaired LA mechanics add to the assessment of patients at risk for IRAF

James Hummel

and 1 more

We thank Medina et al. for their interest in our recent work on QTc prolongation associated with treatment of COVID-19 patients with hydroxychloroquine and azithromycin. As they appropriately point out in their letter, genetic variation is likely a significant determinant of QT prolongation in the population at large and in COVID-19 patients specifically. While drugs causing acquired long QT syndrome and torsades de pointes are generally blockers of IKr, repolarization results from the aggregate of multiple inward and outward currents. Patients with sub-clinical defects in any of these ion channels can have normal or only slightly prolonged baseline QT intervals, but may possess decreased repolarization reserve leading to an exaggerated response to IKr blockade (1).  In our study, a baseline QTc of > 460 ms was associated with excessive QTc prolongation, and this likely represents a group of patients with sub-clinical cardiac ion channel mutations (so called “first hit”) (2). We also agree that many patients with latent mutations demonstrate a normal baseline QT, which gets prolonged with the addition of a drug or a change in the clinical condition “second hit” (3). The patients in our study who exhibited QTc prolongation were generally acutely ill, and displayed “multiple hits” that led to QTc prolongation and it is certainly plausible that many may have had sub-clinical cardiac ion mutations. We therefore wholeheartedly agree that pharmacogenetics should be considered in studies of drug-induced QT prolongation, however this information is rarely available to include for acutely ill patients. And while it makes sense to obtain genetic profiles prior to administration of QT-prolonging medications, that can only be performed in the elective outpatient setting, while taking into consideration medical, ethical and social issues related to asymptomatic genetic screening (e.g. cost, reimbursement, informed consent, etc…). There is significant interest in building genomic databases, and when this becomes a reality for the population at large we believe that genetic information should certainly be included in studies of QT prolongation.Roden DM Long QT syndrome: reduced repolarization reserve and the genetic link. J Intern Med. 2006 Jan; 259(1):59-69.Napolitano C, Schwartz PJ, Brown AM, et al. Evidence for a cardiac ion channel mutation underlying drug-induced QT prolongation and life-threatening arrhythmias. J Cardiovasc Electrophysiol. 2000;11:691–6Sauer AJ and Newton-Cheh C. Clinical and genetic determinants of torsade de pointes risk. Circulation. 2012;125:1684-94.

Jose Lemus Calderon

and 5 more

INTRODUCTION: The SARS-CoV-2 coronavirus pandemic has caused more than fifteen million infections worldwide. Our aim is to investigate the differentiating characteristics in asthmatic patients with SARS-CoV-2 infection in the community of Castilla la Mancha. METHODS: We used the Savana® software and its algorithm based on Big Data and artificial intelligence, performed a retrospective search of the diagnoses of COVID 19 and asthma in the digitized medical records with positive RT-PCR results for SARS-CoV-2, and analysed the demographic characteristics, comorbidities, hospitalization data and deaths. RESULTS: 6,310 patients with positive RT-PCR for SARS-CoV-2 were selected, of which 577 had a diagnosis of asthma with a prevalence of 9.14%. The mean age in SARS-CoV-2 (SC2) was 59 ±19 years of age and in SARS-CoV2-asthma (SC2-A) 55 ±20 years of age. SC2 included 2983 (41%) men and 3327 (59%) women, while SC2-A included 198 (31%) men and 379 (69%) women. High blood pressure (BP) was the most common comorbidity in both groups (51%). 2,164 SC2 (34.2%) and 131 SC2-A (22.7%) required hospitalization with an asthma prevalence of 6.05%. 250 SC2 (3.96%) and 21 SC2-A (3.64%) died. CONCLUSION: The prevalence of asthma in our SARS-CoV-2 positive RT-PCR population was 9.14% and 6.05% in hospitalized patients. HBP is the most frequent comorbidity in both groups, and smoking is the only one with significant differences, more frequent in asthmatics. Mortality is lower in patients with asthma
Drug hypersensitivity reactions (DHRs) represent a global threat to healthcare systems due to their incidence, with a significant increase over last years1. DHR figures are overestimated in the general population since less than 40% of cases initially labelled as allergic can be confirmed as such when evaluated in an allergy unit2. Achieving an accurate diagnosis is complex and time consuming; besides, tests must be tailored to specific clinical manifestations and underlying mechanisms and will depend on the culprit drugs. Diagnosis often requires performing drug provocation tests (DPTs), which are especially problematic for severe reactions, making management of these patients challenging and expensive for the health care system.Clinically, DHRs are classified into immediate and non-immediate, based on the time interval between drug exposure and onset of the symptoms3. The most severe immediate reaction is anaphylaxis. This issue of the journal has been dedicated o drug hypersensitivity, which is becoming a major public health issue during the last decade, especially with the introduction of biologicals to medicine. Bilo et al. 4 evaluated the anaphylaxis mortality rate in Italy from 2004 to 2016 and found an average mortality rate for definite anaphylaxis (ICD-10 code) of 0.51 per million population per year, mostly due to the use of medications (73.7%), although in 98% of the cases culprit drugs were not identified. Regarding non-immediate reactions, one of the most challenging diagnoses is drug reaction with eosinophilia and systemic symptoms (DRESS), which is sometimes difficult, at an early stage, due to overlapping clinical symptoms with maculopapular exanthema (MPE). Pedruzzi et al. 5 identified 7 microRNAs (miRNAs) that correctly classified DRESS or MPE patients and were associated with keratinocyte differentiation/skin inflammation, type I IFN pathway viral replication, ATP-binding cassette transporters, and T lymphocyte polarisation, being all of them potential biomarkers. Non-immunologically mediated adverse reactions, such as attention-deficit/hyperactivity disorder (ADHD) are reported by Fuhrmannet al. 6 in association with systemic H1-antihistamines administration in school-age children, especially the 1st generation agents.The mechanism underlying DHR and the reason why patients treated with the same drug develop a tolerance response or an immediate or non-immediate DHR is not completely understood (Figure 1). Therefore, the prediction of who may experience a DHR, and if so, in what form, remains clinically obscure for most drugs. Goh SJR et al. 7 elegantly analyse this complexity, using non-immediate reactions to penicillins as a model. They focus on the understanding of the role of nature of the lesional T cells, the characterisation of drug-responsive T cells isolated from patient blood, and the potential mechanisms by which penicillins enter the antigen-processing and presentation pathway to stimulate these deleterious responses.Regarding specific drugs involved in allergy, betalactam antibiotics (BL) are the most frequent culprit, being many reactions mediated by IgE. This type of reaction varies among patients, with some reacting only to one BL and others to several of them; it tends to change over time and differs between European countries, depending on BL consumption. Nowadays, amoxicillin (AX), alone or in combination with the β-lactamase inhibitor clavulanic acid (CLV), is the most often prescribed BL worldwide (Figure 2) and the most common elicitor of reactions in both children and adults. It is unclear why patients after the administration of AX-CLV develop selective hypersensitivity to AX, while tolerating CLV and vice-versa. Ariza et al. 8 generated drug-specific T-cell clones from AX- or CLV-selective immediate hypersensitivity patients and found that both AX- and CLV-specific clones were generated irrespective of whether AX or CLV was the culprit, although a higher secretion of Th2 cytokines (IL-13 and IL-5) was detected when clones were activated with the culprit BL compared with clones stimulated with the tolerated BL, in which higher secretion of Th1 cytokines (IFN-γ) was observed. Regarding selective non-immediate reactions to CLV, Copaescu A et al. 9 report on a cohort of patients with a history of non-immediate reaction to CLV, who demonstrated a delayed intradermal skin test response to CLV, 17% were allergic to both CLV and ampicillin, and 83% were selective reactors with good tolerance to AX. IFN-γ release enzyme-linked immunospot (ELISpot) was performed giving a sensitivity of 33%. Other drugs such as sulphonamides, either antibiotic or non-antibiotics are important triggers of non-immediate DHRs. Vilchez-Sanchez et al. 10 showed that lymphocyte transformation tests (LTT) can help avoid the performance of DPT with a sensitivity of 75%, a specificity of 100%, and negative and positive predictive values of 72.7% and 100%, respectively.There has been a great expansion in the use of biological agents (mainly monoclonal antibodies (mAbs)), and they have greatly improved the treatment landscape of hemato-oncologic, autoimmune, inflammatory and rheumatologic diseases. In parallel, the incidence rate of reported DHRs associated with these products has increased considerably within the last years, ranging from mild to life-threatening. Yang BC et al. 11 recommend risk stratification as the first step for managing patients with DHRs to these drugs. In cases with negative skin test and mild reactions, DPT is an option, and in moderate or severe reactions, desensitisation becomes the preferred approach. In cases with positive skin test, desensitisation is the recommended course of action, especially when there is no alternative medication. Desensitisation is also widely used in the management of immediate hypersensitivity reactions to chemotherapy agents, such as platinums. There is suspicion about the presence of a longer memory of tolerance in subsequent desensitisation protocols partially resembling the regulatory tolerance mechanisms induced by allergen immunotherapy. Tüzer et al. 12 demonstrate the possible role of IL-10 in desensitisation with platinums, as they found a dynamic change in serum IL-10 levels observed as an increase during desensitisation and a decrease in between the protocols.Finally, a wide spectrum of drugs has been considered for treatment of coronavirus disease 2019 (COVID-19) and all of them can potentially induce DHRs. Gelincik A et al .13 reviewed DHRs in COVID-19 times to these drugs, with knowledge mainly coming from previous clinical experience in patients not infected with COVID-19. As in other viral infections, skin symptoms, including exanthemas, may appear during the evolution of the disease, leading to differential diagnosis with DHRs. Whether COVID-19 can aggravate T–cell mediated DHRs reactions as some viruses is at present unknown.We can conclude that new drugs are continuously introduced into the markets and confirmed as inducers of hypersensitivity reactions. We still do not completely understand the mechanisms underlying many of these reactions and further studies for improving diagnostic and management are needed even in classic and well-studied drugs as BLs.Abbreviations: AX: Amoxicillin; CLV: Clavulanic acid; COVID-19: Coronavirus disease 2019; DHR: Drug hypersensitivity reactions; DPT: Drug provocation tests; DRESS: Drug reaction with eosinophilia and systemic symptoms; ELISpot: enzyme-linked immunospot; LTT: Lymphocyte transformation tests; MPE: Maculopapular exanthema.

Meilin Schaap

and 4 more

Introduction: To evaluate the long-term (5 years) effects of perioperative briefing and debriefing on team climate. We explored the barriers and facilitators of the performance of perioperative briefing and debriefing to explain its effects on team climate and to make recommendations for further improvement of surgical safety tools. Methods: A mixed-method evaluation study was carried out among surgical staff at a tertiary care university hospital with 593-bed capacity in the Netherlands. Thirteen surgical teams were included. Team climate inventory and a standardised evaluation questionnaire were used to measure team climate (primary outcome) and experiences with perioperative briefing and debriefing (secondary outcome), respectively. Thirteen surgical team members participated in a semi-structured interview to explore barriers and facilitators of the performance of perioperative briefing and debriefing. Results: The dimension ‘participative safety’ increased significantly 5 years after the implementation of perioperative briefing and debriefing (p = 0.02 (95% confidence interval 1.18–9.25)). Perioperative briefing and debriefing was considered a useful method for improving and sustaining participative safety and cooperation within surgical teams. The positive aspects of briefing were that shared agreements made at the start of the day and that briefing enabled participants to work as a team. Participants were less satisfied regarding debriefing, mostly due to the lack of a sense of urgency and a lack of a safe culture for feedback. Briefing and debriefing had less influence on efficiency. Conclusions: Although perioperative briefing and debriefing improves participative safety, the intervention will become more effective for maintaining team climate when teams are complete, irrelevant questions are substituted by customised ones and when there is a safer culture for feedback.

Rand Ibrahim

and 1 more

Sudden Cardiac Death (SCD) remains a global threat.1The most common causes of SCD are ischemic heart diseases and structural cardiomyopathies in the elderly. Additional causes can be arrhythmogenic, respiratory, metabolic, or even toxigenic.2,3,4 Despite the novel diagnostic tools and our deeper understanding of pathologies and genetic associations, there remains a subset of patients for whom a trigger is not identifiable. When associated with a pattern of Ventricular Fibrillation, the diagnosis of exclusion is deemed Idiopathic Ventricular Fibrillation (IVF).2,5 IVF accounts for 5% of all SCDs6 – and up to 23% in the young male subgroup5 – and has a high range of recurrence rates (11-45%).7,8,9 There are still knowledge gaps in the initial assessment, follow-up approach, risk stratification and subsequent management for IVF.1,10,11 While subsets of IVF presentations have been better characterized into channelopathies, such as Brugada’s syndrome (BrS), Long QT Syndrome (LQTS), Early Repolarization Syndrome (ERS), Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), much remains to be discovered.12,13 Implantable Cardioverter Device (ICD) placement as secondary prevention for IVF is the standard of care. This is warranted in the setting of high recurrence rates of arrhythmias (11-43%). Multiple studies have shown potential complications from ICDs and a significant number of cases experiencing inappropriate shock after ICD placement.14In their article, Stampe et al. aim to further understand clinical presentation and assessment, and risk factors for recurrent ventricular arrhythmias in IVF patients. Using a single-centered retrospective study, they followed a total of 84 Danish patients who were initially diagnosed with IVF and received a secondary ICD placement between December 2007 and June 2019. Median follow-up time was 5.2 years (ICR=2-7.6). To ensure detection of many possible underlying etiologies ranging from structural, ischemic, arrhythmogenic, metabolic, or toxicologic, the researchers found that a wide array of diagnostic tools were necessary: standard electrocardiograms (ECGs), high-precordial leads ECGs, standing ECGs, Holter monitoring, sodium-channel blocker provocation tests, exercise stress tests, echocardiograms, cardiac magnetic resonance imaging, coronary angiograms, cardiac computed tomography, electrophysiological studies, histological assessment, blood tests, toxicology screens, and genetic analysis.The study by Stampe et al. highlights the importance of thorough and continuous follow-up with rigorous evaluation: Three (3.6%) patients initially diagnosed with IVF were later found to have underlying cardiac abnormalities (LQTS and Dilated Cardiomyopathy) that explained their SCA. Like other studies, the burden of arrhythmia was found to be high, but unlike reported data, the overall prognosis of IVF was good. Despite the initial pattern of ventricular fibrillation in those who experienced appropriate ICD placement (29.6%), ventricular tachycardia and ventricular fibrillation had a comparable predominance. As for patients with inappropriate ICD placements, atrial fibrillation was a commonly identified pathological rhythm (16.7%). Recurrent cardiac arrest at presentation (19.8%) was a risk factor for appropriate ICD therapy (HR=2.63, CI=1.08-6.40, p=0.033). However, in contrast to previous studies, early repolarization detected on baseline ECG (12.5%), was not found to be a risk factor (p=0.842).The study by Stampe et al. has few limitations. First, the study design, a retrospective cohort, precluded standardized follow-up frequencies and diagnostic testing. Second, while the study was included many of the cofounders tested in previous studies (baseline characteristics, baseline ECG patterns, comorbidities), medication use was not included. Third, the follow-up period may have been insufficient to detect effect from some of the confounding factors. Finally, the sample size was small and it was from a single center.There are several strengths of the Stampe et al. study. Firstly, the wide range of diagnostic tests used at index presentation and during the follow-up period ensured meticulous detection of most underlying etiologies. Secondly, appropriate and well-defined inclusion and exclusion criteria were used. Thirdly, funding by independent parties ensured no influence on study design, result evaluation, and interpretation. Finally, the study has succeeded in improving our understanding of IVF. Future studies should include though a larger population size and a more diverse population.References:1.AlJaroudi WA, Refaat MM, Habib RH, Al-Shaar L, Singh M, et al. Effect of Angiotensin Converting Enzyme Inhibitors and Receptor Blockers on Appropriate Implantable Cardiac Defibrillator Shock: Insights from the GRADE Multicenter Registry. Am J Cardiol Apr 2015; 115 (7): 115(7):924-31.2. Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: executive summary. J Am Coll Cardiol 2018;72:e91–e220.3. Refaat MM, Hotait M, London B: Genetics of Sudden Cardiac Death. Curr Cardiol Rep Jul 2015; 17(7): 6064. Priori SG, Wilde AA, Horie M, Cho Y, Behr ER, Berul C, et al. HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes: document endorsed by HRS, EHRA, and APHRS in May 2013 and by ACCF, AHA, PACES, and AEPC in June 2013. Heart Rhythm 2013;10:1932–1963.5. Priori SG, Blomström-Lundqvist C, Mazzanti A, et al. ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC). Eur Heart J 2015;36(41):2793-2867.6. Zipes DP, Wellens HJ. Sudden cardiac death. Circulation. 1998;98:2334–2351.7. Ozaydin M, Moazzami K, Kalantarian S, Lee H, Mansour M, Ruskin JN. Long-term outcome of patients with idiopathic ventricular fibrillation: a meta-analysis. J Cardiovasc Electrophysiol 2015;26:1095–1104.8. Herman AR, Cheung C, Gerull B, Simpson CS, Birnie DH, Klein GJ, et al. Outcome of apparently unexplained cardiac arrest: results from investigation and follow-up of the prospective cardiac arrest survivors with preserved ejection fraction registry. Circ Arrhythm Electrophysiol 2016;9:e003619.9. Siebermair J, Sinner MF, Beckmann BM, Laubender RP, Martens E, Sattler S, et al.Early repolarization pattern is the strongest predictor of arrhythmia recurrence in patients with idiopathic ventricular fibrillation: results from a single centre long-term follow-up over 20 years. Europace 2016;18:718-25.10. Refaat MM, Hotait M, Tseng ZH: Utility of the Exercise Electrocardiogram Testing in Sudden Cardiac Death Risk Stratification. Ann Noninvasive Electrocardiol 2014; 19(4): 311-318.11. Gray B, Ackerman MJ, Semsarian C, Behr ER. Evaluation after sudden death in the young: a global approach. Circ Arrhythm Electrophysiol 2019;12: e007453.12. Herman AR, Cheung C, Gerull B, Simpson CS, Birnie DH, Klein GJ, et al. Response to Letter Regarding Article, Outcome of apparently unexplained cardiac arrest: results from investigation and follow-up of the prospective cardiac arrest survivors with preserved ejection fraction registry”. Circ Arrhythm Electrophysiol 2016;9:e004012.13. Chen Q, Kirsch GE, Zhang D, Brugada R, Brugada J, Brugada P, Potenza D, et al. Genetic basis and molecular mechanism for idiopathic ventricular fibrillation. Nature 1998;392:293–296.14. Baranchuk A, Refaat M, Patton KK, Chung M, Krishnan K, et al. What Should You Know About Cybersecurity For Cardiac Implantable Electronic Devices? ACC EP Council Perspective. J Am Coll Cardiol Mar 2018; 71(11):1284-1288.

Zengguo Cao

and 17 more

Ebolavirus (EBOV) is responsible for several EBOV disease (EVD) outbreaks in Africa, with a fatality rate of up to 90%. During 2014-2016, An epidemic of EVD spread throughout Sierra Leone, Guinea and Liberia, and killed over 11,000 people. EBOV began to circulate again in the Democratic Republic of Congo in 2018. Due to the need for a BSL-4 facility to manipulate this virus, the development and improvement of specific therapeutics has been hindered. As a result, it is imperative to perform reliable research on EBOV under lowered BSL restrictions. In this study, we developed a safe neutralization assay based on pseudotyped EBOV, which incorporates the glycoprotein of the 2014 EBOV epidemic strain into a lentivirus vector. Our results demonstrated that the tropism of pseudotyped EBOV was similar to that of authentic EBOV, but with only one infection cycle. And neutralizing activity of both authentic EBOV and pseudotyped EBOV were compared in neutralization assay using three different samples of antibody-based reagents against EBOV, similar results were obtained. In addition, an indirect ELISA was performed to show the relationship between IgG and neutralizing antibody against EBOV detected by our pseudotyped EBOV-based neutralization assay. As expected, the neutralizing antibody titers varied with the IgG titers detected by indirect ELISA, and a correlation between the results of the two assays was identified. By comparison with two different assays, the reliability of the results detected by the pseudotyped EBOV-based neutralization assay was confirmed. Collectively, in the absence of BSL-4 restrictions, pseudotyped EBOV production and neutralizing activity evaluation can be performed safely and in a manner that is neither labor- nor time-consuming, providing a simple and safe method for EBOV-neutralizing antibody detection and the assessment of immunogenicity of EBOV vaccines. All these remarkable advantages of the newly established assay highlight its potential to further application in assessment of immunogenicity of EBOV vaccine candidates.
To the Editor, For the EU funded project PERMEABLE (PERsonalized MEdicine Approach for Asthma and Allergy Biologicals SeLEction), which addresses the availability of and access to advanced therapy of asthma in children across Europe, we performed a survey including 37 major pediatric asthma and allergy centers between September 2019 and July 2020. In total, the centers contributing to the survey treated approximately 1.000 young patients with severe asthma in 25 major European countries and Turkey with biologicals. In the light of the Corona Pandemic, we extended our survey asking the responsible clinicians if they experienced a SARS-CoV-2 infection in any of the children they are caring for. The questions pertaining to Corona infections were asked between March and July 2020.Given the prevalence of SARS-CoV-2 infections in the general population and in children, one would expect that at least 1% of the patients would be affected (1). In fact, none of the centers was aware of any symptomatic COVID-19 case in their patient populations or any positive SARS-CoV-2 tests.This leads to the conclusion, that either SARS-CoV-2 infections have a mild or even asymptomatic course also in children with severe asthma or that children with severe asthma (and their parents) were extremely successful in avoiding SARS-CoV-2 infections. Thus, we investigated by structured interview, how centers in those 26 countries had instructed their patients to avoid COVID-19. Interestingly, only 4 European countries (UK, Ireland, Portugal and Malta) had a strict, so called shielding policy in place which followed a principle of maximal segregation of severe asthmatics from the rest of the population: not leaving the house at all, not attending school even when they reopened, wearing face masks also at home, and social distancing even with family members. All other countries followed the principle of continuing or even enforcing asthma treatment in patients and advising to follow the same Corona rules as the general population.Both strategies led to the same result: An absence of COVID-19 cases in children with severe asthma. We conclude from this observation, that shielding is not necessary in children with severe asthma as they and their families are perfectly able to avoid Corona infections. The harm done to children by enforcing seclusion, separation and stigmatization needs to be acknowledged. Deprivation of school, social contact and friends weights heavy on children and the absence of any COVID-19 cases in major European centers for severe asthma in children does not justify a policy of compulsory shielding of children with severe asthma, neither in the first nor in any further Corona wave.Michael Kabesch, M.D.University Children’s Hospital Regensburg (KUNO) at the Hospital St. Hedwig of the Order of St. John, University of Regensburg, Regensburg, Germany.Member of the Research and Development Campus Regensburg (WECARE) at the Hospital St. Hedwig of the Order of St. John, Regensburg, Germany.ReferencesStringhini S, Wisniak A, Piumatti G, et al. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV-POP): a population-based study [published online ahead of print, 2020 Jun 11]. Lancet . 2020;S0140-6736(20)31304-0.

Bachir Lakkis

and 1 more

Long QT syndrome (LQTS) is characterized by prolongation of the QT interval on the electrocardiogram (ECG). Clinically, LQTS is associated with the development of Torsades de Pointes (TdP), a well-defined polymorphic ventricular tachycardia and the development of sudden cardiac death (1). The most common type is the acquired form caused mainly by drugs, it is also known as the drug induced LQTS (diLQTS) (2-5). The diLQTS is caused by certain families of drugs which can markedly prolong the QT interval on the ECG most notably antiarrhythmic drugs (class IA, class III), anti-histamines, antipsychotics, antidepressants, antibiotics, antimalarial, and antifungals (2-5). Some of these agents including the antimalarial drug hydroxycholoquine and the antibiotic azithromycin which are being used in some countries as therapies for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)(6,7). However, these drugs have been implicated in causing prolongation of the QT interval on the ECG (2-5).There is a solution for monitoring this large number of patients which consists of using mobile ECG devices instead of using the standard 12-lead ECG owing to the difficulty of using the 12-lead ECG due to its medical cost and increased risk of transmitting infection. These mobile ECG devices have been shown to be effective in interpreting the QT interval in patients who are using QT interval prolonging drugs (8, 9). However, the ECG mobile devices have been associated with decreased accuracy to interpret the QT interval at high heart rates (9). On the other hand, some of them have been linked with no accuracy to interpret the QT interval (10). This can put some patients at risk of TdP and sudden cardiac death.In this current issue of the Journal of Cardiovascular electrophysiology, Krisai P et al. reported that the limb leads underestimated the occurrence of diLQTS and subsequent TdP compared to the chest leads in the ECG device, this occurred in particular with the usage of mobile standard ECG devices which use limb leads only. To illuminate these findings, the authors have studied the ECGs of 84 patients who have met the requirements for this study, which are diLQTS and subsequent TdP. Furthermore, the patients in this study were also taking a QT interval prolonging drug. Krisai P et al. additionally reported the morphology of the T-wave in every ECG and classified them into flat, broad, notched, late peaked, biphasic and inverted. The authors showed that in 11.9% of these patients the ECG was non reliable in diagnosing diLQTS and subsequent Tdp using only limb leads due to T-wave flattening in these leads, in contrast to chest leads where the non- interpretability of the QT interval was never attributable to the T-wave morphology but to other causes. The authors further examined the QT interval duration in limb leads and chest leads and found that the QT interval in limb leads was shorter compared to that of the chest leads, but reported a high variability in these differences. Therefore, it should be taken into account when screening patients with diLQTS using only mobile ECG devices and these patients should be screened using both limb leads and chest leads. Moreover, the authors have highlighted the limitations of using ECG mobile devices as limb leads to interpret the QT interval especially in high heart rates (when Bazett’s equation overcorrects the QTc and overestimates the prevalence of the QT interval) and have advocated the usage of ECG mobile devices as chest leads instead of limb leads due to their superior ability to interpret the QT interval.The authors should be praised for their efforts in illustrating the difference in the QT interval interpretability between the chest leads and the limb leads in patients with diLQTS. The authors also pointed out the limitation of using mobile ECG devices as limb leads for the diagnosis of diLQTS and recommended their usage as chest leads by applying their leads onto the chest due to their better diagnostic accuracy for detecting the diLQTS. The study results are very relevant, it further expanded the contemporary knowledge about the limitation of the QT interval interpretability using ECG mobile device only (11). Future investigation is needed to elucidate the difference in chest and limb leads interpretability of the QT interval and to assess the ability of the mobile ECG devices to interpret the QT interval.ReferencesRefaat MM, Hotait M, Tseng ZH: Utility of the Exercise Electrocardiogram Testing in Sudden Cardiac Death Risk Stratification. Ann Noninvasive Electrocardiol 2014; 19(4): 311-318.Kannankeril P, Roden D, Darbar D. Drug-Induced Long QT Syndrome. Pharmacological Reviews. 2010;62(4):760-781.Nachimuthu S, Assar M, Schussler J. Drug-induced QT interval prolongation: mechanisms and clinical management. Therapeutic Advances in Drug Safety. 2012;3(5):241-253.Jankelson L, Karam G, Becker M, Chinitz L, Tsai M. QT prolongation, torsades de pointes, and sudden death with short courses of chloroquine or hydroxychloroquine as used in COVID-19: A systematic review. Heart Rhythm. 2020 ; S1547-5271(20)30431-8.Li M, Ramos LG. Drug-Induced QT Prolongation And Torsades de Pointes. P T . 2017;42(7):473-477.Singh A, Singh A, Shaikh A, Singh R, Misra A. Chloroquine and hydroxychloroquine in the treatment of COVID-19 with or without diabetes: A systematic search and a narrative review with a special reference to India and other developing countries. Diabetes & Metabolic Syndrome: Clinical Research & Reviews. 2020;14(3):241-246.Hashem A, Alghamdi B, Algaissi A, Alshehri F, Bukhari A, Alfaleh M et al. Therapeutic use of chloroquine and hydroxychloroquine in COVID-19 and other viral infections: A narrative review. Travel Medicine and Infectious Disease. 2020; 35:101735.Chung E, Guise K. QTC intervals can be assessed with the AliveCor heart monitor in patients on dofetilide for atrial fibrillation. J Electrocardiol. 2015;48(1):8-9.Garabelli P, Stavrakis S, Albert M et al. Comparison of QT Interval Readings in Normal Sinus Rhythm Between a Smartphone Heart Monitor and a 12-Lead ECG for Healthy Volunteers and Inpatients Receiving Sotalol or Dofetilide. Journal Cardiovasc Electrophysiol. 2016;27(7):827-832.Bekker C, Noordergraaf F, Teerenstra S, Pop G, Bemt B. Diagnostic accuracy of a single‐lead portable ECG device for measuring QTc prolongation. Annals Noninvasive Electrocardiol. 2019;25(1): e12683.Malone D, Gallo T, Beck J, Clark D. Feasibility of measuring QT intervals with a portable device. American Journal of Health-System Pharmacy. 2017;74(22):1850-1851.

Volkan Sen

and 9 more

Objectives: There is no standardized and up-to-date education model for urology residents in our country. We aimed to describe our National E learning education model for urology residents. Methodology: The ERTP working group; consisting of urologists was established by Society of Urological Surgery to create E-learning model and curriculum at April 2018. Learning objectives were set up in order to determine and standardize the contents of the presentations. In accordance with the Bloom Taxonomy, 834 learning objectives were created for a total of 90 lectures (18 lectures for each PGY year). Totally 90 videos were shoot by specialized instructors and webcasts were prepared. Webcasts were posted at uropedia.com.tr, which is the web library of Society of Urological Surgery. Satisfaction of residents and instructors was evaluated with feedbacks. An assessment of knowledge was measured with multiple-choice exam. Results: A total of 43 centers and 250 urology residents were included in ERTP during the academic year 2018/2019. There were 93/38/43/34/25 urology residents at 1st/2nd/3rd/4th and 5th year of residency, respectively. Majority of the residents (99.1%) completed the ERTP. The overall satisfaction rate of residents and instructors were 4,29 and 4,67(min:1 so bad, max:5 so good). An assessment exam was performed to urology residents at the end of the ERTP and the mean score was calculated as 57.99 points (min:20, max:82). Conclusion: Due to the Covid-19 pandemic, most of the educational programs had to move online platforms. We used this reliable and easily accessible e-learning platform for standardization of training in urology on national basis. We aim to share this model with international residency training programs.
This paper presents a complete design procedure, with an optimized feeding method, of two-dimensional slotted waveguide antenna arrays (2D SWAs). For a desired sidelobe level ratio, the proposed system provides a pencil shape pattern with a narrow halfpower beamwidth, large sidelobe level ratio (SLR), and very low sidelobe levels (SLL), which makes it suitable for high power microwave applications. The radiating slotted waveguide antennas use longitudinal slots, designed for a specified slidelobe level ratio and resonance frequency. The resulting two-dimensional slotted waveguide antenna array is formed by stacking a number of similarly designed radiating SWAs, and fed with an additional SWA. The proposed feeding method uses longitudinal coupling slots rather than the conventional inclined coupling slots, which can provide better values of SLR and easily obtain very low SLLs, in comparison with the conventional systems. The feeder dimensions and slots positions are deduced from the dimensions and total number of the radiating SWAs. For a desired SLR, the slots excitation in the radiating and feeder SWAs are calculated based on a specified distribution. Then, using simplified closed-form equations and for a desired resonance frequency, the slots lengths, widths, and their distribution along the length of the radiating SWAs and feeder SWA can be found. Two examples are illustrated with different number of slots and radiating elements, and one is fabricated and tested. Chebyshev distribution is used to estimate the excitations of the SWA slots in the examples. The obtained measured and simulated results are in accordance with the design objectives.

Emidio Sivieri

and 3 more

Background: High frequency (HF) oscillatory ventilation has been shown to improve CO2 clearance in premature infants. In a previous in vitro lung model with normal lung mechanics we demonstrated significantly improved CO2 washout by HF oscillation of bubble CPAP (BCPAP). Objective: To examine CO2 clearance in a premature infant lung model with abnormal lung mechanics via measurement of end-tidal CO2 levels (EtCO2) while connected to HF oscillated BCPAP. Design/Methods: A 40mL premature infant lung model with either: normal lung mechanics (NLM): compliance 1.0 mL/cmH2O, airway resistance 56 cmH2O/(L/s); or abnormal lung mechanics (ALM): compliance 0.5 mL/cmH2O, airway resistance 136 cmH2O/(L/s), was connected to BCPAP with HF oscillation at either 4,6,8,10 or 12 Hz. EtCO2 was measured at BCPAPs of 4,6 and 8 cmH2O and respiratory rates (RR) of 40,60 and 80 breaths/min and 6mL tidal volume. Results: HF oscillation decreased EtCO2 levels at all BCPAPs, RRs, and oscillation frequencies for both lung models. Overall mean±SD EtCO2 levels decreased (p<0.001) from non-oscillated baseline by 19.3±10.2% for NLM vs. 14.1±8.8% for ALM. CO2 clearance improved for both lung models (p<0.001) as a function of oscillation frequency and RR with greatest effectiveness at 40-60 breaths/min and HF at 8-12 Hz. Conclusions: In this in-vitro premature infant lung model, HF oscillation of BCPAP was associated with improved CO2 clearance as compared to non-oscillated BCPAP for both NLM and ALM. The significant improvement in CO2 clearance in an abnormal lung environment is an important step towards clinical testing of this novel respiratory support modality.

Colin Garroway

and 1 more

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