Current issues with standards in the measurement and documentation of human skeletal anatomy.

Digital modeling of human anatomy has become increasingly important and relies on well-documented quantitative anatomy literature. This type of documentation is common for the spine and pelvis; however, significant issues exist due to the lack of standardization in measurement and technique. Existing literature on quantitative anatomy for the spine and pelvis of white adults (aged 18-65 years, separated into decadal categories) was reviewed from the disciplines of anatomy, manipulative therapy, anthropometrics, occupational ergonomics, biomechanics and forensic science. The data were unified into a single normative model of the sub-axial spine. Two-dimensional orthographic drawings were produced from the 590 individual measurements identified, which informed the development of a 3D digital model. A similar review of full range of motion data was conducted as a meta-analysis and the results were applied to the existing model, providing an inter-connected, articulated digital spine. During these data analysis processes several inconsistencies were observed accompanied by an evidential lack of standardization with measurement and recording of data. These have been categorized as: anatomical terminology; scaling of measurements; measurement methodology, dimension and anatomical reference positions; global coordinate systems. There is inconsistency in anatomical terminology where independent researchers use the same terms to describe different aspects of anatomy or different terms for the same anatomy. Published standards exist for measurement methods of the human body regarding spatial interaction, anthropometric databases, automotive applications, clothing industries and for computer manikins, but none exists for skeletal anatomy. Presentation of measurements often lacks formal structure in clinical publications, seldom providing geometric reference points, therefore making digital reconstruction difficult. Published quantitative data does not follow existing international published standards relating to engineering drawing and visual communication. Large variations are also evident in standards or guidelines used for global coordinate systems across biomechanics, ergonomics, software systems and 3D software applications. This paper identifies where established good practice exists and suggests additional recommendations, informing an improved communication protocol, to assist reconstruction of skeletal anatomy using 3D digital modeling.

A review of methods used in comprehensive, descriptive studies that relate red blood cell transfusion to clinical data.

BACKGROUND: Red blood cell (RBC) use varies greatly between countries but the underlying reasons are not well understood. Some insight might be gained from blood utilization studies that provide a complete view of the clinical conditions that place individuals at risk of transfusion. This review considers the methodology of published studies that might provide such information and proposes requirements for future studies. STUDY DESIGN AND METHODS: A literature search was performed to identify quantitative studies of RBC use related to clinical data, for which the findings are representative of well-defined populations. Extraction and analysis of methodologic information and epidemiologic data were performed. RESULTS: The 13 studies identified for inclusion varied in their approach to defining the population from which the study sample was selected, classification of clinical data, and method of attributing transfusion events to clinical case groups, including the observational time frame. CONCLUSION: Variability in methods prevents useful interpretation or comparison of the findings. Standardization and transparency of methodology and definitions are essential if future studies are to enable comparison of the factors associated with RBC transfusion in different populations and to improve understanding of the wide variations in RBC use.

Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion.

BACKGROUND: Most clinical practice guidelines recommend restrictive red cell transfusion practices, with the goal of minimising exposure to allogeneic blood (from an unrelated donor). The purpose of this review is to compare clinical outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers). OBJECTIVES: To examine the evidence for the effect of transfusion thresholds on the use of allogeneic and/or autologous blood, and the evidence for any effect on clinical outcomes. SEARCH STRATEGY: Trials were identified by: computer searches of the Cochrane Central Register of Controlled Trials (the Cochrane Library Issue 3, 2009), OVID MEDLINE (1966 to August 2009), Current Contents (1993 to November 2004), and the Web of Science (2004 to August 2009). References in identified trials and review articles were checked and experts contacted to identify any additional trials. SELECTION CRITERIA: Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which an RBC transfusion was to be administered. DATA COLLECTION AND ANALYSIS: Relative risks of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials, using a random effects model. The risk of bias was assessed. MAIN RESULTS: Seventeen trials involving a total of 3746 patients were identified. Restrictive transfusion strategies reduced the risk of receiving a red blood cell (RBC) transfusion by a relative 37% (RR=0.63; 95% CI 0.54 to 0.74). This equates to an average absolute risk reduction (ARR) of 33% (95% CI 21% to 45%). The volume of RBCs transfused was reduced on average by 0.75 units (95% CI 0.20 to 1.30 units). However, heterogeneity between trials was statistically significant (P<0.001; I²≥74%) for these outcomes. Restrictive transfusion strategies did not appear to impact on the rate of adverse events compared to liberal transfusion strategies (i.e. mortality, cardiac events, myocardial infarction, stroke, pneumonia and thromboembolism). Restrictive transfusion strategies were associated with a statistically significant reduction in the rates of infection (RR=0.76; 95% CI 0.60 to 0.97). The use of restrictive transfusion strategies did not reduce hospital or intensive care length of stay. AUTHORS' CONCLUSIONS: The existing evidence supports the use of restrictive transfusion triggers in patients who are free of serious cardiac disease. The effects of conservative transfusion triggers on functional status, morbidity and mortality, particularly in patients with cardiac disease, need to be tested in further large clinical trials. In countries with inadequate screening of donor blood, the data may constitute a stronger basis for avoiding transfusion with allogeneic red cells.