Liam McKeever

Measuring Abdominal Circumference and Skeletal Muscle From a Single Cross-Sectional Computed Tomography Image: A Step-by-Step Guide for Clinicians Using National Institutes of Health ImageJ.

Diagnostic computed tomography (CT) scans provide numerous opportunities for body composition analysis, including quantification of abdominal circumference, abdominal adipose tissues (subcutaneous, visceral, and intermuscular), and skeletal muscle (SM). CT scans are commonly performed for diagnostic purposes in clinical settings, and methods for estimating abdominal circumference and whole-body SM mass from them have been reported. A supine abdominal circumference is a valid measure of waist circumference (WC). The valid correlation between a single cross-sectional CT image (slice) at third lumbar (L3) for abdominal SM and whole-body SM is also well established. Sarcopenia refers to the age-associated decreased in muscle mass and function. A single dimensional definition of sarcopenia using CT images that includes only assessment of low whole-body SM has been validated in clinical populations and significantly associated with negative outcomes. However, despite the availability and precision of SM data from CT scans and the relationship between these measurements and clinical outcomes, they have not become a routine component of clinical nutrition assessment. Lack of time, training, and expense are potential barriers that prevent clinicians from fully embracing this technique. This tutorial presents a systematic, step-by-step guide to quickly quantify abdominal circumference as a proxy for WC and SM using a cross-sectional CT image from a regional diagnostic CT scan for clinical identification of sarcopenia. Multiple software options are available, but this tutorial uses ImageJ, a free public-domain software developed by the National Institutes of Health.

Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Pediatric Critically Ill Patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition

This document represents the first collaboration between two organizations, American Society of Parenteral and Enteral Nutrition and the Society of Critical Care Medicine, to describe best practices in nutrition therapy in critically ill children. The target of these guidelines is intended to be the pediatric (> 1 mo and < 18 yr) critically ill patient expected to require a length of stay greater than 2 or 3 days in a PICU admitting medical, surgical, and cardiac patients. In total, 2,032 citations were scanned for relevance. The PubMed/Medline search resulted in 960 citations for clinical trials and 925 citations for cohort studies. The EMBASE search for clinical trials culled 1,661 citations. In total, the search for clinical trials yielded 1,107 citations, whereas the cohort search yielded 925. After careful review, 16 randomized controlled trials and 37 cohort studies appeared to answer one of the eight preidentified question groups for this guideline. We used the Grading of Recommendations, Assessment, Development and Evaluation criteria to adjust the evidence grade based on assessment of the quality of study design and execution. These guidelines are not intended for neonates or adult patients. The guidelines reiterate the importance of nutritional assessment, particularly the detection of malnourished patients who are most vulnerable and therefore potentially may benefit from timely intervention. There is a need for renewed focus on accurate estimation of energy needs and attention to optimizing protein intake. Indirect calorimetry, where feasible, and cautious use of estimating equations and increased surveillance for unintended caloric underfeeding and overfeeding are recommended. Optimal protein intake and its correlation with clinical outcomes are areas of great interest. The optimal route and timing of nutrient delivery is an area of intense debate and investigations. Enteral nutrition remains the preferred route for nutrient delivery. Several strategies to optimize enteral nutrition during critical illness have emerged. The role of supplemental parenteral nutrition has been highlighted, and a delayed approach appears to be beneficial. Immunonutrition cannot be currently recommended. Overall, the pediatric critical care population is heterogeneous, and a nuanced approach to individualizing nutrition support with the aim of improving clinical outcomes is necessary.

Role of timing and dose of energy received in patients with acute lung injury on mortality in the Intensive Nutrition in Acute Lung Injury Trial (INTACT): A post hoc analysis

BACKGROUND Our trial INTACT (Intensive Nutrition in Acute Lung Injury Trial) was designed to compare the impact of feeding from acute lung injury (ALI) diagnosis to hospital discharge, an interval that, to our knowledge, has not yet been explored. It was stopped early because participants who were randomly assigned to energy intakes at nationally recommended amounts via intensive medical nutrition therapy experienced significantly higher mortality hazards than did those assigned to standard nutrition support care that provided energy at 55% of recommended concentrations. OBJECTIVE We assessed the influence of dose and timing of feeding on hospital mortality. DESIGN Participants (n = 78) were dichotomized as died or discharged alive. Associations between the energy and protein received overall, early (days 1-7), and late (days ≥8) and the hazards of hospital mortality were evaluated between groups with multivariable analysis methods. RESULTS Higher overall energy intake predicted significantly higher mortality (OR: 1.14, 95% CI: 1.02, 1.27). Among participants enrolled for ≥8 d (n = 66), higher early energy intake significantly increased the HR for mortality (HR: 1.17, 95% CI: 1.07, 1.28), whereas higher late energy intake was significantly protective (HR: 0.91, 95% CI: 0.83, 1.0). Results were similar for early but not late protein (grams per kilogram) exposure (early-exposure HR: 8.9, 95% CI: 2.3, 34.3; late-exposure HR: 0.15, 95% CI: 0.02, 1.1). Threshold analyses indicated early mean intakes ≥18 kcal/kg significantly increased subsequent mortality. CONCLUSIONS Providing kilocalories per kilogram or grams of protein per kilogram early post-ALI diagnosis at recommended levels was associated with significantly higher hazards for mortality, whereas higher late energy intakes reduced mortality hazards. This time-varying effect violated the Cox proportionality assumption, indicating that feeding trials in similar populations should extend beyond 7 d and use time-varying statistical methods. Future trials are required for corroboration. INTACT was registered at clinicaltrials.gov as NCT01921101.

Demystifying the Search Button: A Comprehensive PubMed Search Strategy for Performing an Exhaustive Literature Review

A thorough review of the literature is the basis of all research and evidence-based practice. A gold-standard efficient and exhaustive search strategy is needed to ensure all relevant citations have been captured and that the search performed is reproducible. The PubMed database comprises both the MEDLINE and non-MEDLINE databases. MEDLINE-based search strategies are robust but capture only 89% of the total available citations in PubMed. The remaining 11% include the most recent and possibly relevant citations but are only searchable through less efficient techniques. An effective search strategy must employ both the MEDLINE and the non-MEDLINE portion of PubMed to ensure all studies have been identified. The robust MEDLINE search strategies are used for the MEDLINE portion of the search. Usage of the less robust strategies is then efficiently confined to search only the remaining 11% of PubMed citations that have not been indexed for MEDLINE. The current article offers step-by-step instructions for building such a search exploring methods for the discovery of medical subject heading (MeSH) terms to search MEDLINE, text-based methods for exploring the non-MEDLINE database, information on the limitations of convenience algorithms such as the “related citations feature,” the strengths and pitfalls associated with commonly used filters, the proper usage of Boolean operators to organize a master search strategy, and instructions for automating that search through “MyNCBI” to receive search query updates by email as new citations become available.

ASPEN-FELANPE Clinical Guidelines: Nutrition Support of Adult Patients With Enterocutaneous Fistula

Background: The management of patients with enterocutaneous fistula (ECF) requires an interdisciplinary approach and poses a significant challenge to physicians, wound/stoma care specialists, dietitians, pharmacists, and other nutrition clinicians. Guidelines for optimizing nutrition status in these patients are often vague, based on limited and dated clinical studies, and typically rely on individual institutional or clinician experience. Specific nutrient requirements, appropriate route of feeding, role of immune-enhancing formulas, and use of somatostatin analogues in the management of patients with ECF are not well defined. The purpose of this clinical guideline is to develop recommendations for the nutrition care of adult patients with ECF. Methods: A systematic review of the best available evidence to answer a series of questions regarding clinical management of adults with ECF was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group. An anonymous consensus process was used to develop the clinical guideline recommendations prior to peer review and approval by the ASPEN Board of Directors and by FELANPE. Questions: In adult patients with enterocutaneous fistula: (1) What factors best describe nutrition status? (2) What is the preferred route of nutrition therapy (oral diet, enteral nutrition, or parenteral nutrition)? (3) What protein and energy intake provide best clinical outcomes? (4) Is fistuloclysis associated with better outcomes than standard care? (5) Are immune-enhancing formulas associated with better outcomes than standard formulas? (6) Does the use of somatostatin or somatostatin analogue provide better outcomes than standard medical therapy? (7) When is home parenteral nutrition support indicated?

Early Exposure to Recommended Calorie Delivery in the Intensive Care Unit Is Associated With Increased Mortality in Patients With Acute Respiratory Distress Syndrome

BACKGROUND The Intensive Nutrition in Acute Lung Injury: Clinical Trial (INTACT), designed to evaluate outcomes of calorie delivery from acute respiratory distress syndrome (ARDS) diagnosis through hospital discharge, was stopped due to higher mortality in the intervention group. Post hoc analysis found timing and dose of calorie delivery influenced mortality. The objective of this retrospective cohort study was to determine if early vs late calorie exposure changed the hazard of death among a larger sample of patients with ARDS. METHODS Adult patients who met the eligibility criteria for INTACT but did not participate were included. Daily calorie delivery was collected from the date INTACT eligibility was determined to extubation or death. Cox proportional hazards regression was used to model the relationship between hazard of hospital death with average calorie exposure received over increasing study days and after day 7. RESULTS A total of 298 patients were included; overall mortality was 33%. Among patients who remained intubated at 1 week (n = 202), higher kcal/kg received from intensive care unit (ICU) days 1-6 increased hazards of subsequent death on days 7+ (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.01-1.06); kcal/kg received after ICU day 7 decreased the hazards of death on day 7+ (HR, 0.53; 95% CI, 0.33-0.84). CONCLUSIONS Higher calorie exposure between ICU days 1 and 7 was associated with higher subsequent hazard of mortality, and provision of high-calorie exposure after day 8 decreased the hazards of death.

Primer on Study Design, Type I and Type II Errors, Power, and Statistical Significance to Ensure Interpretation of Clinical Trial Results Remains Clearly INTACT

We thank Drs. Patel, Martindale, and Heyland1 for their interest in our most recent study2 exploring the role of early exposure to recommended energy delivery in critically ill patients with acute respiratory distress syndrome. Their stated concerns center around 3 major areas: (1) the comparability of the population in our study2 with those of INTACT (Intensive Nutrition in Acute Lung Injury: A Clinical Trial); (2) their confusion on the analysis of the relationship between the likelihood of death with energy exposure (table 1 in our article2 ); and (3) their apparent misunderstanding of type I error, type II error, P-values, and power analysis. Our responses to each of these areas are detailed as follows.

American Society for Parenteral and Enteral Nutrition Guidelines for the Selection and Care of Central Venous Access Devices for Adult Home Parenteral Nutrition Administration

This document represents the American Society for Parenteral and Enteral Nutrition (ASPEN) clinical guidelines to describe best practices in the selection and care of central venous access devices (CVADs) for the infusion of home parenteral nutrition (HPN) admixtures in adult patients. The guidelines targeted adults >18 years of age in which the intervention or exposure had to include HPN that was administered via a CVAD. Case studies, non-English studies, or studies of CVAD no longer available in the United States were excluded. In total, 564 abstract citations, 350 from Medline and 214 from PubMed/non-MEDLINE databases, were scanned for relevance. Of the 564 citations, 13 studies addressed at least 1 of the 6 guideline-related questions, and none of the studies were prospective and randomized. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria were used to adjust the evidence grade based on assessment of the quality of study design and execution. Recommendations for the CVAD type, composition, or number of lumens to minimize infectious or mechanical complications are based on a limited number of studies and expert opinion of the authors, all very experienced in home infusion therapy. No studies were found that compared best solutions for routine flushing of lumens (eg, heparin versus saline) or for maintaining catheters in situ while treating CVAD mechanical or infectious complications. It is clear that studies to answer these questions are very limited, and further research is needed. These clinical guidelines were approved by the ASPEN Board of Directors.

Feeding During Phases of Altered Mitochondrial Activity: A Theory

Decisions surrounding the timing and dosing of nutrition support are made for thousands of ICU patients daily and yet remain a topic of controversy. Nutrition support designed to replenish resting energy expenditure (REE) early in critical illness has led to worse clinical outcomes in at least three recent prospective randomized clinical trials. Producing sufficient energy from nutrient substrates requires use of the mitochondrial electron transport chain (ETC). This process is functionally linked to the creation of a tightly regulated series of chemical messengers known as reactive oxygen species (ROS). In health, ROS are kept at low levels by a system of mitochondrial/cellular enzymes and antioxidants, allowing ROS to act as a signal for the redox health of the cell. In inflammatory conditions, however, this system is altered, leading to changes in the physiologic function of the ETC such that its usage produces greater ROS per unit of substrate. This increased ROS is capable of deactivating antioxidant systems, as well as activating further ROS-producing pathways and stimulating localized inflammatory activity. We propose that exacerbation of this process at this time by the forced influx of exogenously acquired nutrient substrates leads to mitochondrial damage, amplified ROS production, increased inflammation, decreased ATP-productive capacity, and, eventually, the death of the cell by either apoptosis or necrosis. Knowledge of this process is vital to determining the safe dosing and timing of nutrition support in the ICU. It is possible that the physiologic cost of meeting the REE under these conditions of mitochondrial stress may simply be too high. This paper details the proposed process by which inappropriately timed feeding in critically ill patients may damage the very mitochondria required for its utilization.