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1.
Crit Care Med ; 51(8): 1023-1032, 2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-36971440

RESUMEN

OBJECTIVES: Studies have suggested intrapulmonary shunts may contribute to hypoxemia in COVID-19 acute respiratory distress syndrome (ARDS) with worse associated outcomes. We evaluated the presence of right-to-left (R-L) shunts in COVID-19 and non-COVID ARDS patients using a comprehensive hypoxemia workup for shunt etiology and associations with mortality. DESIGN: Prospective, observational cohort study. SETTING: Four tertiary hospitals in Edmonton, Alberta, Canada. PATIENTS: Adult critically ill, mechanically ventilated, ICU patients admitted with COVID-19 or non-COVID (November 16, 2020, to September 1, 2021). INTERVENTIONS: Agitated-saline bubble studies with transthoracic echocardiography/transcranial Doppler ± transesophageal echocardiography assessed for R-L shunts presence. MEASUREMENTS AND MAIN RESULTS: Primary outcomes were shunt frequency and association with hospital mortality. Logistic regression analysis was used for adjustment. The study enrolled 226 patients (182 COVID-19 vs 42 non-COVID). Median age was 58 years (interquartile range [IQR], 47-67 yr) and Acute Physiology and Chronic Health Evaluation II scores of 30 (IQR, 21-36). In COVID-19 patients, the frequency of R-L shunt was 31 of 182 COVID patients (17.0%) versus 10 of 44 non-COVID patients (22.7%), with no difference detected in shunt rates (risk difference [RD], -5.7%; 95% CI, -18.4 to 7.0; p = 0.38). In the COVID-19 group, hospital mortality was higher for those with R-L shunt compared with those without (54.8% vs 35.8%; RD, 19.0%; 95% CI, 0.1-37.9; p = 0.05). This did not persist at 90-day mortality nor after adjustment with regression. CONCLUSIONS: There was no evidence of increased R-L shunt rates in COVID-19 compared with non-COVID controls. R-L shunt was associated with increased in-hospital mortality for COVID-19 patients, but this did not persist at 90-day mortality or after adjusting using logistic regression.


Asunto(s)
COVID-19 , Síndrome de Dificultad Respiratoria , Humanos , Adulto , Persona de Mediana Edad , Estudios Prospectivos , Ecocardiografía , Hipoxia , Unidades de Cuidados Intensivos , Alberta
2.
Am Surg ; 89(12): 5407-5413, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36789639

RESUMEN

BACKGROUND: The Focused Assessment with Sonography in Trauma (FAST) exam is an important component to the evaluation of trauma patients. With advances in technology and meeting limitations due to COVID-19, remote instruction and learning have gained popularity. We sought to determine whether remote instruction of FAST exams was feasible as sustainable surgical education and a possible alternative to traditional in-person teaching. METHODS: General surgery residents completed a baseline survey and skills assessment on FAST exams and were then randomized to remote or in-person instruction. The remote group participated in an instructional session with a content expert through video conference and then practiced on a simulated mannequin while the expert remotely provided feedback. The in-person group received the experience with the content expert in the room. Both groups completed a post-course survey immediately after the session and a follow-up survey and objective assessment at six-months. Results were compared with two-way analysis of variance (ANOVA). RESULTS: 14 residents underwent the curriculum, seven in each group. There was a significant increase in self-reported confidence when comparing pre- and immediate post-course results for both the remote and in-person groups. At six months, confidence scores remained elevated and skill assessment scores improved, although the latter did not reach significance. There was no significant difference in post-course results between the groups. CONCLUSIONS: Remote instruction of FAST exams was feasible. Pilot data demonstrated an increase in confidence and suggest outcomes that are similar to in-person instruction, which has positive implications for future remote educational and potentially clinical initiatives.


Asunto(s)
Evaluación Enfocada con Ecografía para Trauma , Internado y Residencia , Humanos , Proyectos Piloto , Curriculum , Ultrasonografía , Escolaridad , Competencia Clínica
3.
IEEE J Biomed Health Inform ; 27(1): 227-238, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36136928

RESUMEN

The COVID-19 pandemic has highlighted the need for a tool to speed up triage in ultrasound scans and provide clinicians with fast access to relevant information. To this end, we propose a new unsupervised reinforcement learning (RL) framework with novel rewards to facilitate unsupervised learning by avoiding tedious and impractical manual labelling for summarizing ultrasound videos. The proposed framework is capable of delivering video summaries with classification labels and segmentations of key landmarks which enhances its utility as a triage tool in the emergency department (ED) and for use in telemedicine. Using an attention ensemble of encoders, the high dimensional image is projected into a low dimensional latent space in terms of: a) reduced distance with a normal or abnormal class (classifier encoder), b) following a topology of landmarks (segmentation encoder), and c) the distance or topology agnostic latent representation (autoencoders). The summarization network is implemented using a bi-directional long short term memory (Bi-LSTM) which utilizes the latent space representation from the encoder. Validation is performed on lung ultrasound (LUS), that typically represent potential use cases in telemedicine and ED triage acquired from different medical centers across geographies (India and Spain). The proposed approach trained and tested on 126 LUS videos showed high agreement with the ground truth with an average precision of over 80% and average F1 score of well over 44 ±1.7 %. The approach resulted in an average reduction in storage space of 77% which can ease bandwidth and storage requirements in telemedicine.


Asunto(s)
COVID-19 , Humanos , Pandemias , Pulmón/diagnóstico por imagen , Ultrasonografía , India
4.
Crit Care Explor ; 4(11): e0789, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36382336

RESUMEN

Acute respiratory distress syndrome (ARDS) is a life-threatening respiratory injury with multiple physiological sequelae. Shunting of deoxygenated blood through intra- and extrapulmonary shunts may complicate ARDS management. Therefore, we conducted a systematic review to determine the prevalence of sonographically detected shunts, and their association with oxygenation and mortality in patients with ARDS. DATA SOURCES: Medical literature analysis and retrieval system online, Excerpta Medica dataBASE, Cochrane Library, and database of abstracts of reviews of effects databases on March 26, 2021. STUDY SELECTION: Articles relating to respiratory failure and sonographic shunt detection. DATA EXTRACTION: Articles were independently screened and extracted in duplicate. Data pertaining to study demographics and shunt detection were compiled for mortality and oxygenation outcomes. Risk of bias was appraised using the Joanna-Briggs Institute and the Newcastle-Ottawa Scale tools with evidence rating certainty using Grading of Recommendations Assessment, Development and Evaluation methodology. DATA SYNTHESIS: From 4,617 citations, 10 observational studies met eligibility criteria. Sonographic detection of right-to-left shunt was present in 21.8% of patients (range, 14.4-30.0%) among included studies using transthoracic, transesophageal, and transcranial bubble Doppler ultrasonographies. Shunt prevalence may be associated with increased mortality (risk ratio, 1.22; 95% CI, 1.01-1.49; p = 0.04, very low certainty evidence) with no difference in oxygenation as measured by Pao2:Fio2 ratio (mean difference, -0.7; 95% CI, -18.6 to 17.2; p = 0.94, very low certainty). CONCLUSIONS: Intra- and extrapulmonary shunts are detected frequently in ARDS with ultrasound techniques. Shunts may increase mortality among patients with ARDS, but its association with oxygenation is uncertain.

5.
J Environ Manage ; 302(Pt A): 113952, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34872172

RESUMEN

Restoring stream ecosystem integrity by removing unused or derelict dams has become a priority for watershed conservation globally. However, efforts to restore connectivity are constrained by the availability of accurate dam inventories which often overlook smaller unmapped riverine dams. Here we develop and test a machine learning approach to identify unmapped dams using a combination of publicly available topographic and geospatial habitat data. Specifically, we trained a random forest classification algorithm to identify unmapped dams using digitally engineered predictor variables and known dam sites for validation. We applied our algorithm to two subbasins in the Hudson River watershed, USA, and quantified connectivity impacts, as well as evaluated a range of predictor sets to examine tradeoffs between classification accuracy and model parameterization effort. The random forest classifier achieved high accuracy in predicting dam sites (true positive rate = 89%, false positive rate = 1.2%) using a subset of variables related to stream slope and presence of upstream lentic habitats. Unmapped dams were prevalent throughout the two test watersheds. In fact, existing dam inventories underestimated the true number of dams by ∼80-94%. Accounting for previously unmapped dams resulted in a 62-90% decrease in dendritic connectivity indices for migratory fishes. Unmapped dams may be pervasive and can dramatically bias stream connectivity information. However, we find that machine learning approaches can provide an accurate and scalable means of identifying unmapped dams that can guide efforts to develop accurate dam inventories, thereby informing and empowering efforts to better manage them.


Asunto(s)
Ecosistema , Ríos , Animales , Peces , Aprendizaje Automático , Prevalencia
6.
Ultrasound J ; 13(1): 48, 2021 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-34897552

RESUMEN

BACKGROUND: Critical care ultrasound (CCUS) is now a core competency for Canadian critical care medicine (CCM) physicians, but little is known about what education is delivered, how competence is assessed, and what challenges exist. We evaluated the Canadian CCUS education landscape and compared it against published recommendations. METHODS: A 23-item survey was developed and incorporated a literature review, national recommendations, and expert input. It was sent in the spring of 2019 to all 13 Canadian Adult CCM training programs via their respective program directors. Three months were allowed for data collection and descriptive statistics were compiled. RESULTS: Eleven of 13 (85%) programs responded, of which only 7/11 (64%) followed national recommendations. Curricula differed, as did how education was delivered: 8/11 (72%) used hands-on training; 7/11 (64%) used educational rounds; 5/11 (45%) used image interpretation sessions, and 5/11 (45%) used scan-based feedback. All 11 employed academic half-days, but only 7/11 (64%) used experience gained during clinical service. Only 2/11 (18%) delivered multiday courses, and 2/11 (18%) had mandatory ultrasound rotations. Most programs had only 1 or 2 local CCUS expert-champions, and only 4/11 (36%) assessed learner competency. Common barriers included educators receiving insufficient time and/or support. CONCLUSIONS: Our national survey is the first in Canada to explore CCUS education in critical care. It suggests that while CCUS education is rapidly developing, gaps persist. These include variation in curriculum and delivery, insufficient access to experts, and support for educators.

8.
Can J Anaesth ; 68(1): 71-80, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33089414

RESUMEN

PURPOSE: Experts recommend that critical care medicine (CCM) practitioners should be adept at critical care ultrasound (CCUS). Published surveys highlight that many institutions have no deliberate strategy, no formalized curriculum, and insufficient engagement of CCM faculty and trainees. Consequently, proficiency is non-uniform. Accordingly, we performed a needs assessment to develop an inter-professional standardized CCUS curriculum as a foundation towards universal basic fluency. METHODS: Mixed-methods study of CCM trainees, attendings, and nurse practitioners working across five academic and community medical-surgical intensive care units in Edmonton, Alberta. We used qualitative focus groups followed by quantitative surveys to explore, refine, and integrate results into a curriculum framework. RESULTS: Focus groups with 19 inter-professional practitioners identified major themes including perceived benefits, learning limitations, priorities, perceived risks, characteristics of effective instruction, ensuring long-term success, and achieving competency. Sub-themes highlighted rapid attrition of skill following one- to two-day workshops, lack of skilled faculty, lack of longitudinal training, and the need for site-based mentorship. Thirty-five practitioners (35/70: 50%) completed the survey. Prior training included workshops (16/35; 46%) and self-teaching (11/35; 31%). Eleven percent (4/35) described concerns about potential errors in CCUS performance. The survey helped to refine resources, content, delivery, and assessment. Integration of qualitative and quantitative findings produced a comprehensive curriculum framework. CONCLUSION: Building on published recommendations, our needs assessment identified additional priorities for a CCUS curriculum framework. Specifically, there is a perceived loss of skills following short workshops and insufficient strategies to sustain learning. Addressing these deficits could narrow the gap between national recommendations and frontline needs.


RéSUMé: OBJECTIF: Les experts recommandent que les intensivistes soient habiles en échographie aux soins intensifs. Les sondages publiés révèlent que de nombreux établissements ne possèdent pas de stratégie réfléchie ni de curriculum formalisé en échographie, tout en souffrant d'un manque d'implication du corps professoral et des résidents. Les aptitudes ne sont donc pas uniformes. C'est pourquoi nous avons réalisé une évaluation des besoins afin de mettre au point un curriculum interprofessionnel standardisé en échographie aux soins intensifs qui servira de fondation vers une maîtrise des aptitudes de bases universelles. MéTHODE: Nous avons réalisé une étude en méthodes mixtes auprès de résidents, de patrons et d'infirmiers et infirmières praticiens en soins intensifs travaillant dans cinq unités de soins intensifs médico-chirurgicaux universitaires et communautaires à Edmonton, en Alberta. Nous avons formé des groupes de réflexion qualitatifs puis avons réalisé des sondages quantitatifs afin d'explorer, d'approfondir et d'intégrer nos résultats dans un cadre de curriculum. RéSULTATS: Des groupes de réflexion composés de 19 praticiens interprofessionnels ont identifié des thèmes majeurs, notamment les avantages perçus, les obstacles à l'apprentissage, les priorités, les risques perçus, les caractéristiques d'un enseignement efficace, l'assurance d'un succès à long terme et l'acquisition des compétences. Les sous-thèmes ont mis en lumière une attrition rapide des compétences après des ateliers d'un ou deux jours, le manque d'enseignants compétents, le manque de formation longitudinale, et le besoin de mentorat sur le lieu de travail. Trente-cinq praticiens (35/70; 50 %) ont répondu au sondage. Les formations antérieures incluaient des ateliers (16/35; 46 %) et de l'auto-apprentissage (11/35; 31 %). Onze pourcent (4/35) des répondants ont fait part d'inquiétudes concernant les erreurs potentielles dans la performance de l'échographie aux soins intensifs. Le sondage a permis de raffiner les ressources, le contenu, la livraison et l'évaluation. L'intégration des résultats qualitatifs et quantitatifs a permis de réaliser un cadre exhaustif de curriculum. CONCLUSION: En nous appuyant sur les recommandations publiées, notre évaluation des besoins a identifié des priorités supplémentaires pour encadrer une formation d'échographie destinée aux soins intensifs. Plus spécifiquement, il existe une perte perçue des compétences à la suite d'ateliers courts et il manque de stratégies pour soutenir l'apprentissage. En palliant ces manques, il pourrait être possible de réduire le fossé entre les recommandations nationales et les besoins en première ligne.


Asunto(s)
Cuidados Críticos , Curriculum , Alberta , Humanos , Evaluación de Necesidades , Ultrasonografía
9.
J Ultrasound Med ; 40(9): 1879-1892, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33274782

RESUMEN

OBJECTIVES: To develop a consensus statement on the use of lung ultrasound (LUS) in the assessment of symptomatic general medical inpatients with known or suspected coronavirus disease 2019 (COVID-19). METHODS: Our LUS expert panel consisted of 14 multidisciplinary international experts. Experts voted in 3 rounds on the strength of 26 recommendations as "strong," "weak," or "do not recommend." For recommendations that reached consensus for do not recommend, a fourth round was conducted to determine the strength of those recommendations, with 2 additional recommendations considered. RESULTS: Of the 26 recommendations, experts reached consensus on 6 in the first round, 13 in the second, and 7 in the third. Four recommendations were removed because of redundancy. In the fourth round, experts considered 4 recommendations that reached consensus for do not recommend and 2 additional scenarios; consensus was reached for 4 of these. Our final recommendations consist of 24 consensus statements; for 2 of these, the strength of the recommendations did not reach consensus. CONCLUSIONS: In symptomatic medical inpatients with known or suspected COVID-19, we recommend the use of LUS to: (1) support the diagnosis of pneumonitis but not diagnose COVID-19, (2) rule out concerning ultrasound features, (3) monitor patients with a change in the clinical status, and (4) avoid unnecessary additional imaging for patients whose pretest probability of an alternative or superimposed diagnosis is low. We do not recommend the use of LUS to guide admission and discharge decisions. We do not recommend routine serial LUS in patients without a change in their clinical condition.


Asunto(s)
COVID-19 , Pacientes Internos , Canadá , Consenso , Humanos , Pulmón/diagnóstico por imagen , SARS-CoV-2
10.
J Environ Manage ; 272: 111051, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32677622

RESUMEN

Current research on flooding risk often focuses on understanding hazards, de-emphasizing the complex pathways of exposure and vulnerability. We investigated the use of both hydrologic and social demographic data for flood exposure mapping with Random Forest (RF) regression and classification algorithms trained to predict both parcel- and tract-level flood insurance claims within New York State, US. Topographic characteristics best described flood claim frequency, but RF prediction skill was improved at both spatial scales when socioeconomic data was incorporated. Substantial improvements occurred at the tract-level when the percentage of minority residents, housing stock value and age, and the political dissimilarity index of voting precincts were used to predict insurance claims. Census tracts with higher numbers of claims and greater densities of low-lying tax parcels tended to have low proportions of minority residents, newer houses, and less political similarity to state level government. We compared this data-driven approach and a physically-based pluvial flood routing model for prediction of the spatial extents of flooding claims in two nearby catchments of differing land use. The floodplain we defined with physically based modeling agreed well with existing federal flood insurance rate maps, but underestimated the spatial extents of historical claim generating areas. In contrast, RF classification incorporating hydrologic and socioeconomic demographic data likely overestimated the flood-exposed areas. Our research indicates that quantitative incorporation of social data can improve flooding exposure estimates.


Asunto(s)
Inundaciones , Hidrología , Aprendizaje Automático , New York , Factores Socioeconómicos
11.
Ultrasound J ; 12(1): 19, 2020 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-32307598

RESUMEN

BACKGROUND: Point-of-care ultrasound (POCUS) is increasingly used in internal medicine, but a lack of trained faculty continues to limit the spread of POCUS education. Using a framework based on organizational change theories, this study sought to identify barriers and enablers for hospital-based practicing internists to learn and use POCUS in clinical practice. METHODS: We invited practicing internists at six North American institutions to participate in an electronic survey on their opinions regarding 39 barriers and enablers. RESULTS: Of the 342 participants invited, 170 participated (response rate 49.3%). The top barriers were lack of training (79%), lack of handheld ultrasound devices (78%), lack of direct supervision (65%), lack of time to perform POCUS during rounds (65%), and lack of quality assurance processes (53%). The majority of participants (55%) disagreed or strongly disagreed with the statement "My institution provides funding for POCUS training." In general, participants' attitudes towards POCUS were favourable, and future career opportunities and the potential for billing were not considered significant factors by our participants in the decision to learn or use POCUS. CONCLUSIONS: This survey confirms the perceived importance of POCUS to practicing internists. To assist in closing faculty development gap, interventions should address training, supervision, quality assurance processes, availability of handheld devices, as well as dedicated time to perform POCUS during clinical care.

12.
J Gen Intern Med ; 35(2): 624, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31953680

RESUMEN

This editorial, "Internal Medicine Point of Care Ultrasound: Indicators It's Here to Stay" (DOI: 10.1007/s11606-019-05268-0), was intended to accompany "Education Indicators for Internal Medicine Point-of-Care Ultrasound: a Consensus Report from the Canadian Internal Medicine Ultrasound (CIMUS) Group".

13.
J Gen Intern Med ; 34(10): 2123-2129, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31240603

RESUMEN

BACKGROUND: Curriculum development and implementation for internal medicine point-of-care ultrasound (IM POCUS) continues to be a challenge for many residency training programs. Education indicators may provide a useful framework to support curriculum development and implementation efforts across programs in order to achieve a consistent high-quality educational experience. OBJECTIVE: This study seeks to establish consensus-based recommendations for education indicators for IM POCUS training programs in Canada. DESIGN: This consensus study uses a modified nominal group technique for voting in the initial round, followed by two additional rounds of online voting, with consensus defined as agreement by at least 80% of the participants. PARTICIPANTS: Participants were 22 leaders with POCUS and/or education expertise from 13 Canadian internal medicine residency programs across 7 provinces. MAIN MEASURES: Education indicators considered were those that related to aspects of the POCUS educational system, could be presented by a single statistical measure, were readily understood, could be reliably measured to provide a benchmark for measuring change, and represented a policy issue. We excluded a priori indicators with low feasibility, are impractical, or assess learner reactions. Candidate indicators were drafted by two academic internists with post-graduate training in POCUS and medical education. These indicators were reviewed by two internists with training in quality improvement prior to presentation to the expert participants. KEY RESULTS: Of the 52 candidate education indicators considered, 6 reached consensus in the first round, 12 in the second, and 4 in the third round. Only 5 indicators reached consensus to be excluded; the remaining indicators did not reach consensus. CONCLUSIONS: The Canadian Internal Medicine Ultrasound (CIMUS) group recommends 22 education indicators be used to guide and monitor internal medicine POCUS curriculum development efforts in Canada.


Asunto(s)
Curriculum , Medicina Interna/educación , Pruebas en el Punto de Atención/normas , Ultrasonografía/métodos , Canadá , Humanos
14.
Indian J Crit Care Med ; 22(9): 650-655, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30294131

RESUMEN

BACKGROUND: Excessive extravascular lung water (EVLW) is associated with increased morbidity and mortality. We compared three lung-ultrasound (L-US) techniques against the reference-standard transpulmonary thermodilution (TPTD) technique to access EVLW. MATERIALS AND METHODS: This was a prospective, single-blind, cross-sectional study. Forty-four septic patients were enrolled. EVLW index was measured by the TPTD method, and an index of ≥10 mL/kg was considered diagnostic of pulmonary edema. EVLW index was then compared to three established bedside L-US protocols that evaluate sonographic B-lines: (1) a 28-zone protocol (total B-line score [TBS]) (2) a scanning 8-region examination, and (3) a 4-point examination. RESULTS: Eighty-nine comparisons were obtained. A statistically significant positive correlation was found between L-US TBS and an EVLW index ≥10 mL/kg (r = 0.668,P < 0.001). The 28-zone protocol score ≥39 has a sensitivity of 81.6% and a specificity of 76.5% to define EVLW index ≥10 mL/kg. In contrast, the positive 4-point examination and scanning 8-regions showed low sensitivity (23.7% and 50.0%, respectively) but high specificity (96.1% and 88.2%, respectively). Ten patients with a total of 21 comparisons met criteria for acute respiratory distress syndrome (ARDS). In this subgroup, only the TBS had statistically significant positive correlation to EVLW (r = 0.488,P = 0.025). CONCLUSION: L-US is feasible in patients with severe sepsis. In addition, L-US 28-zone protocol demonstrated high specificity and better sensitivity than abbreviated 4- and 8-zone protocols. In ARDS, the L-US 28-zone protocol was more accurate than the 4- and 8-zone protocols in predicting EVLW. Consideration of limitations of the latter protocols may prevent clinicians from reaching premature conclusions regarding the prediction of EVLW. TRIAL REGISTRATION: ISRCTN11419081. Registered 4 February 2015 retrospectively.

17.
Ecol Appl ; 27(1): 37-55, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-28052494

RESUMEN

Quantitative flow-ecology relationships are needed to evaluate how water withdrawals for unconventional natural gas development may impact aquatic ecosystems. Addressing this need, we studied current patterns of hydrologic alteration in the Marcellus Shale region and related the estimated flow alteration to fish community measures. We then used these empirical flow-ecology relationships to evaluate alternative surface water withdrawals and environmental flow rules. Reduced high-flow magnitude, dampened rates of change, and increased low-flow magnitudes were apparent regionally, but changes in many of the flow metrics likely to be sensitive to withdrawals also showed substantial regional variation. Fish community measures were significantly related to flow alteration, including declines in species richness with diminished annual runoff, winter low-flow, and summer median-flow. In addition, the relative abundance of intolerant taxa decreased with reduced winter high-flow and increased flow constancy, while fluvial specialist species decreased with reduced winter and annual flows. Stream size strongly mediated both the impact of withdrawal scenarios and the protection afforded by environmental flow standards. Under the most intense withdrawal scenario, 75% of reference headwaters and creeks (drainage areas <99 km2 ) experienced at least 78% reduction in summer flow, whereas little change was predicted for larger rivers. Moreover, the least intense withdrawal scenario still reduced summer flows by at least 21% for 50% of headwaters and creeks. The observed 90th quantile flow-ecology relationships indicate that such alteration could reduce species richness by 23% or more. Seasonally varying environmental flow standards and high fixed minimum flows protected the most streams from hydrologic alteration, but common minimum flow standards left numerous locations vulnerable to substantial flow alteration. This study clarifies how additional water demands in the region may adversely affect freshwater biological integrity. The results make clear that policies to limit or prevent water withdrawals from smaller streams can reduce the risk of ecosystem impairment.


Asunto(s)
Biota , Peces , Fracking Hidráulico , Industria del Petróleo y Gas , Ríos , Movimientos del Agua , Animales , Región de los Apalaches , Hidrología , Gas Natural
19.
J Environ Manage ; 128: 1050-9, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-23933218

RESUMEN

Roadside ditches are ubiquitous, yet their role in water pollution conveyance has largely been ignored, especially for bacteria and sediment. The goal of this study was to determine if roadside ditches are conduits for fecal indicator organisms and sediment, and if land use, specifically manure amendment, affects the concentrations and loadings. Seven roadside ditches in central New York, adjacent to either manure amended fields or predominately forested land, were monitored for one year for Escherichia coli (E. coli), total suspended solids (TSS) and flow. E. coli concentrations in water samples following storms averaged 4616 MPN of E. coli/100 mL. Concentrations reached as high as >241,960 MPN of E. coli/100 mL and frequently exceeded New York State and US EPA recommendations. Concentrations peaked in both summers following manure spreading, with declining levels thereafter. However, viable organisms were detected throughout the year. The concentrations were also high in the forested sites, with possible sources including wildlife, pets, septic wastes and livestock. E. coli concentrations and loadings were related to TSS concentrations and loadings, whether manure had been spread in the last 30 days and for concentrations only, antecedent rainfall. Viable E. coli were also present in ditch sediment between storm events and were available for resuspension and transport. Total suspended solids concentrations averaged 0.51 g/L and reached as high as 52.2 g/L. Loads were similarly high, at an average of 631.6 kg/day. Both concentrations and loads tended to be associated with discharge and rainfall parameters. The cumulative pollutant contribution from the ditch network was estimated to be large enough to produce detectable and sometimes high concentrations in a receiving stream in a small, rural watershed. Roadside drainage networks need to be actively managed for water quality improvements, because they capture and rapidly shunt stormwater and associated contaminants to streams.


Asunto(s)
Heces/microbiología , Sedimentos Geológicos/microbiología , Calidad del Agua , Animales , Escherichia coli/aislamiento & purificación , Ganado , Estiércol , New York , Mascotas , Lluvia , Microbiología del Agua
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