The fractional exhaled nitric oxide (FE
) test is a point-of-care test that is used in the assessment of asthma.
To provide evidence-based clinical guidance on whether FE
testing is indicated to ...optimize asthma treatment in patients with asthma in whom treatment is being considered.
An international, multidisciplinary panel of experts was convened to form a consensus document regarding a single question relevant to the use of FE
. The question was selected from three potential questions based on the greatest perceived impact on clinical practice and the unmet need for evidence-based answers related to this question. The panel performed systematic reviews of published randomized controlled trials between 2004 and 2019 and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) evidence-to-decision framework to develop recommendations. All panel members evaluated and approved the recommendations.
After considering the overall low quality of the evidence, the panel made a conditional recommendation for FE
-based care. In patients with asthma in whom treatment is being considered, we suggest that FE
is beneficial and should be used in addition to usual care. This judgment is based on a balance of effects that probably favors the intervention; the moderate costs and availability of resources, which probably favors the intervention; and the perceived acceptability and feasibility of the intervention in daily practice.
Clinicians should consider this recommendation to measure FE
in patients with asthma in whom treatment is being considered based on current best available evidence.
Surveys of the North American race of the Red Knot (Calidris canutus rufa) on its main wintering areas on the coasts of Patagonia and Tierra del Fuego (Argentina and Chile) showed a dramatic decline ...in the wintering population: totals in 2003 were about 30 000 compared to 67 500 in the mid-1980s. Numbers at the principal wintering site, Bahia Lomas, fell by approximately 50%, from 45 300 in 2000 to 22 000–25 000 in 2002–2003. Numbers at peripheral sites on the coast of Patagonia declined dramatically, decreasing 98% compared to numbers in the mid-1980s. The results showed that declines at core sites did not result from birds moving to other places within the known wintering (or other) areas, but reflected a general population decline, with most birds now restricted to key sites in Tierra del Fuego. This phenomenon may explain why long-term declines noted elsewhere have only recently become apparent at key wintering areas. Possible reasons for the declines are discussed. Banding studies in Delaware Bay have shown that in recent years an increasing proportion of Red Knots is unable to gain sufficient weight for migration to the breeding grounds. This is likely due to reductions in their main food resource, eggs of the horseshoe crab Limulus polyphemus. The resulting increase in mortality could account for the magnitude and severity of the declines we observed. Disminuciones en las Poblaciones Invernantes de Calidris canutus rufa en el Sur de Sur América Resumen. Censos de la raza norteamericana de Calidris canutus (rufa) en sus áreas de invernada principales en las costas de la Patagonia y Tierra del Fuego (Argentina y Chile) mostraron una disminución dramática en la población invernante. Los totales en 2003 fueron aproximadamente 30 000, comparados con 67 500 a mediados de los años 80. Los números en el sitio principal de invernada (Bahía Lomas) decayeron en aproximadamente un 50%, de 45 300 en 2000 a 22 000–25 000 en 2002–2003. Los números en sitios periféricos en la costa de Patagonia declinaron dramáticamente, en un 98% en comparación con los números de mediados de los ochenta. Los resultados mostraron que las disminuciones en los sitios núcleo no fueron el resultado de que las aves se movieran a otros sitios dentro del rango invernal conocido, o a otras áreas. En cambio, reflejaron una disminución general de la población; la mayoría de las aves están ahora restringidas a sitios claves en Tierra del Fuego. Este fenómeno podría explicar por qué las disminuciones poblacionales de largo plazo detectadas en otros lugares sólo se han hecho aparentes ahora en las áreas claves de invernada. Se discuten las posibles causas de las disminuciones. Estudios de anillamiento en la bahía de Delaware han mostrado que en años recientes una mayor proporción de las aves es incapaz de incrementar su peso hasta los niveles necesarios para la migración hacia las áreas de invernada. Esto probablemente es debido a reducciones en su principal recurso alimenticio, los huevos de Limulus polyphemus. El incremento en mortalidad resultante podría explicar la magnitud y la severidad de las disminuciones poblacionales que observamos.
Shorebirds are thought to be declining across North America but trend analyses for migrant shorebirds at interior sites in eastern North America have not been updated since the late 1990s. Data from ...a volunteer-based survey at stopover sites throughout Ontario were used to assess population trends of shorebirds over the period 1974–2009. Surveyors carried out 7,135 surveys of 258 sites and recorded 538,744 individuals of 43 shorebird species. Of 19 taxa for which trends were estimated, 17 appeared to be declining in abundance. Precision of the trend estimates was generally poor and only three declines were significant at α = 0.05. Total numbers of shorebirds recorded on surveys declined by four per cent per year, resulting in an estimated decrease in abundance of greater than 75% over the 35 years of observation. Rate of decline may be increasing for some species as declines for twelve species were larger for the period 1989–2009 vs. 1974–1989, and six species showed significant declines in the latter period whereas none did in the former period. Relating these declines in abundance at the surveyed sites to population declines is complicated by several potential sources of survey bias including changes in turnover rates and in migration timing and distributions of the species. However, given that these results are consistent with those of other migration surveys as well as those on the breeding and the wintering grounds, the most parsimonious explanation remains a widespread decline in shorebird populations.
The Mississippi Flyway midwinter population survey (MWS) indicates that American black ducks (Anas rubripes) have been rapidly declining for the last 10 years. We found a negative relationship ...between MWS and Ontario (Canada) midwinter counts for black ducks. Thus, as number of black ducks in the MWS decreased, Ontario midwinter counts increased. A shift in midwinter distribution of black ducks may be partly responsible for the decreasing trend in MWS counts. We recommend that midwinter black duck surveys be expanded to more sites in southern Canada and northeastern United States that currently are not sampled to better assess winter habitat use and improve the midwinter black-duck population index.
Concern about declining populations of sea ducks counted on the wintering grounds prompted a survey of sea ducks on the breeding grounds in the Hudson Bay Lowlands of Ontario in spring 2009. We ...estimated densities of breeding scoters (Surf Scoter, Melanitta perspicillata, White-winged Scoter, M. fusca, and Black Scoter, M. americana) and found the average estimates of Surf Scoters (average = 0.11 indicated pairs/km2) and Black Scoters (average = 0.16 indicated pairs/km2) to be as high as some of the highest reported for North America. We also conducted a habitat association analysis using resource selection functions (RSF) for indicated pairs of all scoter species combined at a scale of 250 m. Breeding pairs of scoters in the Hudson Bay Lowlands appear to have an affinity for smaller wetlands (≤100 ha) disproportionate to what is available, also avoiding lakes (i.e., wetlands >100 ha). Pairs were also found in areas with less forest cover and fen area than was available. An estimate of the area under the curve of the receiver operating characteristic suggests that these habitat association models have some utility. Once tested and validated with surveys beyond the current study area, these models can be refined and used to predict habitat use by breeding pairs of scoters in the Hudson Bay Lowlands; this information will be particularly useful for population estimation and land use planning.
In the 1980's, aerial surveys in South America established that the main wintering areas of Semipalmated Sandpipers (Calidris pusilla) were found on the north coast of the continent, especially in ...the Guianas (Suriname, French Guiana and Guyana). Although population trend analyses have consistently shown declines in numbers of Semipalmated Sandpipers, especially for birds on migration in eastern North America, until now surveys had not been undertaken to determine whether such declines were reflected in numbers on the main wintering areas. Between December 2008 and January 2011, aerial surveys of major wintering areas in Suriname (3), French Guiana (2) and Guyana (1) were carried out. Results showed dramatic declines, with an overall total of only 21% of the 1980s total—a decrease of 79%. A variety of reasons may have contributed to the declines and include habitat changes, range shifts, sustained hunting, or increases in predation, pollution or severe weather.
We propose a wetland habitat classification for boreal forest waterfowl that builds on existing classification systems, and apply the habitat classification to wetlands surveyed for 14 species of ...waterfowl breeding pairs and broods in the boreal Claybelt of Ontario. The habitat classification is based on simple and easily observable structural characteristics measured from black-and-white aerial photography collected for forest resource inventories. Habitat associations were examined using χ2analysis for individual waterfowl species, and canonical correspondence analysis for overall community structure. Habitat use deviated significantly from that expected by random association for both pairs and broods, and canonical ordination of habitat/community structure was significant for both breeding pairs and broods. Beaver-pond marshes, lacustrine marshes located at river mouths, and open-water fens with <25% vegetative cover were used at rates much higher than expected, and deserve attention for conservation in the boreal forest. Based on expected distribution of wetland habitat types, we estimate 96.9 pairs × 100 km-2and 96.1 broods × 100 km-2to occur on average throughout the Claybelt.
Diving ducks staging on the lower Great Lakes have responded to the introduction and subsequent population increase of zebra mussels (Dreissena polymorpha) by consuming this readily available food. ...However, nutritional and contaminant-related implications of recent dietary shifts are hindered by the fact that few studies have documented foods consumed by diving ducks before zebra mussels invaded the Great Lakes in 1988. We examined diets of greater scaup (Aythya marila), lesser scaup (Aythya affinis), and long-tailed ducks (Clangula hyemalis) collected from eastern Lake Ontario during autumn 1986 and 1987 to determine differences among the 3 species. Gastropods were the main food item of greater (92% aggregate dry mass) and lesser scaup (86%), but they consumed relatively small amounts (3% and 7%, respectively) of amphipods. In contrast, amphipods made up 66% of the diets of long-tailed ducks; gastropods were 28% of their diet. Amphipod populations have increased and native gastropods decreased in the presence of zebra mussels in the lower Great Lakes, such that zebra mussel invasion likely has had greater dietary implications for scaup than for long-tailed ducks. Dietary shifts from nonfilter-feeding gastropods to filter-feeding zebra mussels likely contributed to elevated contaminant burdens in lesser and greater scaup on the lower Great Lakes. We encourage further research into the diet-, nutrient-, and contaminant-related implications of zebra mussel induced ecological changes to the Great Lakes.
The abundance and distribution of breeding waterfowl in the Great Clay Belt of northern Ontario was determined through helicopter surveys of 117 fixed plots (2 x 2 km each) during the nest initiation ...periods from 1988 to 1990. This area has higher fertility, flat topography, high water table and better access than the surrounding Boreal Forest, and therefore has greater potential for increased waterfowl production through habitat management. Overall breeding density averaged 112.5 indicated breeding pairs per 100 km super(2), 68% being of the four most common species Mallard (Anas platyrhynchos), Ring-necked Duck (Aythya collaris), American Black Duck (Anas rubripes), and Common Goldeneye (Bucephala clangula); 13 other species were encountered. The average total of breeding waterfowl for the region was estimated at 59330 pairs. Distributions of the species were related to ecodistrict and to surficial geology. The more northerly of the two main ecodistricts had higher densities of American Black Ducks, Ring-necked Ducks, Common Goldeneyes, and Canada Geese (Branta canadensis). Mallard and Hooded Merganser (Lophodytes cucullatus) distributions correlated with presence of surficial clay and moraines, respectively. Less common species including Green-winged Teal (Anas crecca) and American Wigeon (Anas americana) appeared to be concentrated in smaller-scaled habitat features (beaver pond sequences and estuarine marshes, respectively). Results generally agreed with those of earlier Clay Belt surveys. Total breeding density of waterfowl is slightly higher than that of surrounding regions.
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