1,720,971 research outputs found
Effect of Relative Decrease in Blood Hemoglobin Concentrations on Postoperative Morbidity in Patients Who Undergo Major Gastrointestinal Surgery
No full textIMPORTANCE Delta hemoglobin (Delta Hb), defined as the difference between the preoperative hemoglobin (Hb) level and the nadir Hb level during a patient's hospitalization, may be associated with adverse outcomes even if the absolute level of Hb remains greater than the transfusion threshold of 7 g/dL. OBJECTIVE To evaluate the association between Delta Hb and morbidity in patients who undergo major gastrointestinal surgery as an independent factor or combined with the nadir Hb concentration. DESIGN, SETTING, AND PARTICIPANTS Retrospective review of prospectively collected data on patients who underwent pancreatic, hepatic, or colorectal resection from January 1, 2010, through April 30, 2014, at Johns Hopkins Hospital were included in the study. Data regarding the Delta Hb concentration following surgery, nadir Hb level, and overall perioperative blood use were obtained and analyzed. Multivariable-adjusted logistic regression models were used to identify the preoperative factors associated with Delta Hb and the effect of Delta Hb on perioperative morbidity. The study and data analysis took place from January 22 through February 20, 2015. INTERVENTIONS Major gastrointestinal surgery and packed red blood cell transfusion. MAIN OUTCOMES AND MEASURES Overall morbidity and ischemic-specific complications. RESULTS Of the 4669 patients who underwent major gastrointestinal surgery, the median Delta Hb level after surgery was 40%. Patients with multiple comorbidities (American Society of Anesthesiologists Physical Status score of 3-4: odds ratio [OR], 1.96; 95% CI, 1.30-2.97; P = 3 coexisting medical conditions: OR, 1.62; 95% CI, 1.08-2.42; P = .001) and those who underwent pancreatic surgery (OR, 1.98; 95% CI, 1.18-3.33; P = .01) were at increased risk of having a Delta Hb of 50% or greater. Compared with patients who had a Delta Hb level of less than 50% and a nadir Hb level of 7 g/dL or greater, patients with a Delta Hb level of 50% or greater whose nadir Hb level was less than 7 g/dL were at a high risk of developing postoperative complications (OR, 6.60; 95% CI, 4.34-10.03; P <.001); in particular, a Delta Hb level of 50% or greater was strongly correlated with a risk of ischemic complications, even if the nadir Hb level was 7 g/dL or greater (OR, 5.68; 95% CI, 1.44-22.39; P = .01). CONCLUSIONS AND RELEVANCE A Delta Hb level of 50% or greater following gastrointestinal surgery was associated with complications, especially ischemic adverse events, even if the nadir Hb level remained at 7 g/dL or greater
Potential Economic Impact of Using a Restrictive Transfusion Trigger Among Patients Undergoing Major Abdominal Surgery
No full textIMPORTANCE Transfusion practice among surgeons varies despite several evidence-based recommendations supporting the restrictive use of blood products. OBJECTIVE To define the economic impact of liberal blood transfusions as assessed through an analysis of hemoglobin (Hb) triggers. DESIGN, SETTING, AND PARTICIPANTS Using a prospective database, data on Hb levels that triggered a transfusion and overall blood product use were obtained for patients undergoing pancreas, liver, or colorectal surgery between January 1, 2010, and August 31, 2013, at Johns Hopkins Hospital. An economic analysis was performed using a range of costs for a single unit of packed red blood cells (PRBCs) based on actual institutional acquisition costs (760/unit). Guidelines define a liberal Hb trigger as transfusion of PRBCs for an intraoperative Hb level of 10 g/dL or greater or a postoperative Hb level of 8 g/dL or greater (to convert to grams per liter, multiply by 10.0). MAIN OUTCOMES AND MEASURES Numbers of surgical patients who received PRBC transfusion, estimated cost per transfusion, and estimated cost of excessive blood transfusions. RESULTS Among 3027 patients, 942 (31.1%) received at least 1 PRBC transfusion, intraoperatively in 264 patients (8.7%), postoperatively in 429 (14.2%), or both in 249 (8.2%). A total of 4000 units of PRBCs (range, 0-167 units/patient) were transfused in the intraoperative (1581 units [39.5%]) and postoperative (2419 units [60.5%]) periods. Estimated total costs of PRBC transfusion ranged from 3 040 000, with marked variation in costs per patient across procedure type and surgeon. Among the 942 patients who received a transfusion, 456 units (11.4%) were transfused using a liberal trigger (intraoperative, 122 patients [13.0%]; postoperative, 79 patients [8.4%]). By adopting a restrictive trigger, total overall PRBC transfusion costs may have been reduced by 346 560 during the 44-month study period or 94 516 per year for patients undergoing a pancreas, liver, or colorectal resection. CONCLUSIONS AND RELEVANCE More than 1 in 10 units of PRBCs were transfused using a liberal Hb trigger. Patient blood management programs should aim to identify and reduce liberal transfusion practice in the surgical patient
Defining Transfusion Triggers and Utilization of Fresh Frozen Plasma and Platelets Among Patients Undergoing Hepatopancreaticobiliary and Colorectal Surgery
No full textBackground:We sought to define the overall utilization of fresh frozen plasma (FFP) and platelets and the impact on perioperative outcomes among patients undergoing hepatopancreaticobiliary and colorectal resections, as well as analyze the utility of laboratory triggers in guiding transfusion practice.Methods:We identified 3027 patients undergoing pancreatic, hepatic, and colorectal resections between 2010 and 2013 at Johns Hopkins Hospital. Data on international normalized ratio (INR) and platelet counts that triggered the perioperative utilization of these non-RBC (red blood cell) products were obtained and analyzed.Results:Overall FFP and platelet transfusion rates were 8.9% and 3.8%, respectively. Mean INR and platelet triggers for FFP and platelet transfusions were 1.9 1.3 and 60000 +/- 44000, respectively. INR triggers varied depending on resection type, patient race, and comorbidity status (all P1, P <0.001).Conclusions:The utilization and indication of non-RBC components vary significantly across surgical specialties. Nearly one-half of patients transfused with FFP during the postoperative period had an INR of less than 1.7, indicating possible overutilization of these products. Furthermore, the use of FFP and platelets are associated with poorer perioperative outcomes. Further studies are needed to study the impact and management of a more restrictive use of FFP and platelets on surgical patients
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
Identifying Variations in Blood Use Based on Hemoglobin Transfusion Trigger and Target among Hepatopancreaticobiliary Surgeons
No full textBACKGROUND: Transfusion practice among surgeons varies despite several trials supporting the restrictive use of blood products. We sought to define the variation in surgeon transfusion hemoglobin (Hb) triggers and targets among patients undergoing hepatopancreaticobiliary (HPB) procedures, as well as assess perioperative outcomes among patients receiving transfusions under a restrictive vs liberal transfusion strategy. STUDY DESIGN: Using prospectively collected data, variations in transfusion Hb triggers, targets, and overall use of blood were examined among 1,554 patients undergoing an HPB procedure by 1 of 11 surgeons at Johns Hopkins Hospital between 2009 and 2013. Perioperative outcomes were compared among patients treated with a restrictive (Hb = 8 g/dL) transfusion strategy. RESULTS: Among the 1,554 patients included in the cohort, 504 (32.4%) received at least 1 transfusion of red cells. Patients who received a transfusion were older and had more medical comorbidities (both p 0.05). CONCLUSIONS: Nearly 1 in 3 patients undergoing an HPB procedure received a blood transfusion in the perioperative period. Transfusion use, indication ("trigger"), and dose ("target") varied among surgeons. The use of a restrictive transfusion strategy did not affect perioperative outcomes. (C) 2014 by the American College of Surgeon
Variation in triggers and use of perioperative blood transfusion in major gastrointestinal surgery
No full textBackground: The decision to perform intraoperative blood transfusion is subject to a variety of clinical and laboratory factors. This study examined variation in haemoglobin (Hb) triggers and overall utilization of intraoperative blood transfusion, as well the impact of transfusion on perioperative outcomes. Methods: The study included all patients who underwent pancreatic, hepatic or colorectal resection between 2010 and 2013 at Johns Hopkins Hospital, Baltimore, Maryland. Data on Hb levels that triggered an intraoperative or postoperative transfusion and overall perioperative blood utilization were obtained and analysed. Results: Intraoperative transfusion was employed in 437 (15.6 per cent) of the 2806 patients identified. Older patients (odds ratio (OR) 1.68), patients with multiple co-morbidities (Charlson co-morbidity score 4 or above; OR 1.66) and those with a lower preoperative Hb level (OR 4.95) were at increased risk of intraoperative blood transfusion (all P < 0.001). The Hb level employed to trigger transfusion varied by sex, race and service (all P < 0.001). A total of 105 patients (24.0 per cent of patients transfused) had an intraoperative transfusion with a liberal Hb trigger (10 g/dl or more); the majority of these patients (78; 74.3 per cent) did not require any additional postoperative transfusion. Patients who received an intraoperative transfusion were at greater risk of perioperative complications (OR 1.55; P = 0.002), although patients transfused with a restrictive Hb trigger (less than 10 g/dl) showed no increased risk of perioperative morbidity compared with those transfused with a liberal Hb trigger (OR 1.22; P = 0.514). Conclusion: Use of perioperative blood transfusion varies among surgeons and type of operation. Nearly one in four patients received a blood transfusion with a liberal intraoperative transfusion Hb trigger of 10 g/dl or more. Intraoperative blood transfusion was associated with higher risk of perioperative morbidity
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
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