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Nutritional requirements and gas-exchange: is it possible to perform indicrect calorimetry in children undergoing nasal CPAP?
No full textIntroduction. Nutrition plays a pivotal role in critically ill children and personalized nutritional therapy requires the measurement of resting energy expenditure (REE) [1-2]. Indirect calorimetry (IC) is the gold standard for REE assessment and is based on VO2 and VCO2 measurements. Furthermore, IC provides information on carbohydrates/lipids consumption by defining the respiratory quotient (RQ). In spontaneously breathing patients, IC is performed using a transparent helmet (Canopy mode). The helmet is placed on patients’ head and is connected to the calorimeter through a tube. An aspiration flow generated by the calorimeter allows gas collection and analysis. In mechanically ventilated patients, the measurements are performed connecting IC analyzers to
the ventilator circuit. However, while IC is validated for spontaneously breathing and mechanically ventilated patients, it is not for patients undergoing CPAP (continuous positive airway pressure) [3]. This limitation is of great clinical relevance, as the use of CPAP and other non-invasive modes of ventilation is increasing in the pediatric intensive care units (PICUs).
The aim of the present study is therefore to validate IC in children undergoing nasal CPAP (n-CPAP) by comparing IC results obtained during spontaneous breathing with data gathered during n-CPAP.
Methods. Patients (age <6 years) admitted to our PICU from February to May 2019 and treated with n-CPAP were enrolled. Patients were studied during the weaning phase, i.e., once they were able to maintain spontaneous breathing in room air. In order to test the validity of IC during n-CPAP, two measurements were performed in Canopy mode for 20 minutes, in randomized order with the following settings: 1) Spontaneous breathing (SB), 2) n-CPAP of 4 cmH2O. A turbine-driven ventilator with a single-limb circuit and a vented nasal mask was used to deliver n-CPAP. Of note, in this way, both intentional and non-intentional leaks remained in the canopy helmet.
Total minute flow delivered by the ventilator was measured by a Fleisch pneumotachograph connected to the respiratory circuit, in order to personalize the aspiration flow setting [4]. Average values for VCO2, VO2, RQ and REE were obtained in these two conditions. Comparison between groups was performed via paired t-test.
Agreement was assessed via Bland-Altman analysis. Statistical significance was defined as p<0.05.
Results. Five patients (median age 16 months, IQR 9 months, median weight 8.5 kg, IQR 0.6 kg) were enrolled.
All patients were in resting state during both measurements, thus allowing for standardized conditions. VCO2, VO2, RQ and REE did not differ significantly between groups. Bias and Limits of Agreement (LOA) indicate a good agreement between the two measures (Table 1).
Conclusions. Our preliminary data suggest that IC can be accurately performed in children undergoing n-CPAP using a single limb circuit with intentional leaks. These results need to be confirmed on a broader cohort of critically ill children.
References
1. De Cosmi V et al. Nutrients. 2017
2. Mehta NM et al. Pediatr Crit Care Med. 2017
3. Taku Oshima et al. Clinical Nutr. 2017
4. Smallwood CD et al. J Parenter Enteral Nutr. 201
Gas-exchange and resting energy expenditure measurement with indirect calorimetry in children supported with non-invasive ventilation
No full textIntroduction. Nutrition plays a fundamental role in critically ill children and personalized nutritional therapy requires the measurement of resting energy expenditure (REE) [1-2]. Indirect calorimetry (IC) is the gold standard for REE assessment and is based on VO2 and VCO2 measurements. Furthermore, IC provides information on carbohydrates/lipids consumption by defining the respiratory quotient (RQ). However, while IC is validated for spontaneously breathing and mechanically ventilated patients, it is not for patients undergoing non-invasive ventilation (NIV) [3].
Aim of the study is therefore to validate IC for children undergoing NIV by comparing IC results obtained during spontaneous breathing with data gathered during NIV-CPAP (continuous positive airway pressure).
Methods. Patients (age <6 years) admitted to our pediatric intensive care unit (PICU) and weaning from NIV-CPAP were enrolled. Two IC measurements (Canopy mode) were performed for 20 minutes in randomized order in the following conditions: 1) Spontaneous breathing (SB), 2) NIV-CPAP (performed by single-limb circuit and vented mask). Average values for VCO2 , VO2, RQ and REE were obtained in the two conditions. Comparison between groups was performed via paired t-test. Agreement was assessed via Bland-Altman analysis. Statistical significance was defined as p<0.05.
Results. Four patients (median age 8 months, median weight 8 kg) were enrolled. VCO2 , VO2, RQ and REE did not differ significantly between groups. Limits of agreement (LOA) and BIAS indicate a good agreement between the two measures (Table 1).
Conclusions. Our preliminary data suggest that IC can be accurately performed in children undergoing NIV using a single limb circuit with intentional leaks. These results need to be confirmed on a broader cohort of critically ill children.
References
1. De Cosmi V et al. Nutrients. 2017, 18:9
2. Mehta NM et al. Pediatr Crit Care Med. 2017, 18:675-715
3. Taku Oshima et al. Clinical Nutr 2017; 36:651-66
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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