Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Choice architecture modifies fruit and vegetable purchasing in a university campus grocery store: time series modelling of a natural experiment

Background

In developed countries, adolescent and young adult diets have been found to be nutritionally poor. The aim of this study was to examine whether a choice architecture intervention, re-arrangement of produce within a grocery store to increase the accessibility of fruit and vegetables, affected purchasing behaviour on a university campus.

Methods

A database of daily sales data from January 2012 to July 2017 was obtained from a campus grocery store. Two changes to the layout were made during this time period. In January 2015, fruit and vegetables were moved from the back of the store, furthest from the entrance, to the aisle closest to the entrance and an entrance-facing display increasing their accessibility. In April 2016, the entrance-facing display of fruit and vegetables was replaced with a chiller cabinet so that fruit and vegetables remained more accessible than during the baseline period, but less accessible than in the period immediately previously. A retrospective interrupted time series analysis using dynamic regression was used to model the data and to examine the effect of the store re-arrangements on purchasing. All analyses were carried out both for sales-by-quantity and for sales-by-money.

Results

The first shop re-arrangement which made fruit and vegetables more prominent, increased the percentage of total sales that were fruit and vegetables, when analysed by either items purchased or money spent. The second rearrangement also had a positive effect on the percentage of total sales that were fruit and vegetables compared to baseline, however this was not significant at the 5% level. Over the five year period, the percentage of sales that were fruit and vegetables declined both in terms of items purchased, and money spent.

Conclusions

Increasing accessibility of fruit and vegetables in a grocery store is a feasible way to improve the diet of students in tertiary education. There is evidence of declining fruit and vegetable consumption among the studied population, which should be further investigated.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6063-8) contains supplementary material, which is available to authorized users.

Association of a Surgical Task During Training With Team Skill Acquisition Among Surgical Residents: The Missing Piece in Multidisciplinary Team Training

Importance

The human patient simulators that are currently used in multidisciplinary operating room team training scenarios cannot simulate surgical tasks because they lack a realistic surgical anatomy. Thus, they eliminate the surgeon's primary task in the operating room. The surgical trainee is presented with a significant barrier when he or she attempts to suspend disbelief and engage in the scenario.

Objective

To develop and test a simulation-based operating room team training strategy that challenges the communication abilities and teamwork competencies of surgeons while they are engaged in realistic operative maneuvers.

Design, Setting, and Participants

This pre-post educational intervention pilot study compared the gains in teamwork skills for midlevel surgical residents at Wake Forest Baptist Medical Center after they participated in a standardized multidisciplinary team training scenario with 3 possible levels of surgical realism: (1) SimMan (Laerdal) (control group, no surgical anatomy); (2) "synthetic anatomy for surgical tasks" mannequin (medium-fidelity anatomy), and (3) a patient simulated by a deceased donor (high-fidelity anatomy).

Interventions

Participation in the simulation scenario and the subsequent debriefing.

Main Outcomes and Measures

Teamwork competency was assessed using several instruments with extensive validity evidence, including the Nontechnical Skills assessment, the Trauma Management Skills scoring system, the Crisis Resource Management checklist, and a self-efficacy survey instrument. Participant satisfaction was assessed with a Likert-scale questionnaire.

Results

Scenario participants included midlevel surgical residents, anesthesia providers, scrub nurses, and circulating nurses. Statistical models showed that surgical residents exposed to medium-fidelity simulation (synthetic anatomy for surgical tasks) team training scenarios demonstrated greater gains in teamwork skills compared with control groups (SimMan) (Nontechnical Skills video score: 95% CI, 1.06-16.41; Trauma Management Skills video score: 95% CI, 0.61-2.90) and equivalent gains in teamwork skills compared with high-fidelity simulations (deceased donor) (Nontechnical Skills video score: 95% CI, -8.51 to 6.71; Trauma Management Skills video score: 95% CI, -1.70 to 0.49).

Conclusions and Relevance

Including a surgical task in operating room team training significantly enhanced the acquisition of teamwork skills among midlevel surgical residents. Incorporating relatively inexpensive, medium-fidelity synthetic anatomy in human patient simulators was as effective as using high-fidelity anatomies from deceased donors for promoting teamwork skills in this learning group.

Features predicting weight loss in overweight or obese participants in a web-based intervention: randomized trial

Background

Obesity remains a serious issue in many countries. Web-based programs offer good potential for delivery of weight loss programs. Yet, many Internet-delivered weight loss studies include support from medical or nutritional experts, and relatively little is known about purely web-based weight loss programs.

Objective

To determine whether supportive features and personalization in a 12-week web-based lifestyle intervention with no in-person professional contact affect retention and weight loss.

Methods

We assessed the effect of different features of a web-based weight loss intervention using a 12-week repeated-measures randomized parallel design. We developed 7 sites representing 3 functional groups. A national mass media promotion was used to attract overweight/obese Australian adults (based on body mass index [BMI] calculated from self-reported heights and weights). Eligible respondents (n = 8112) were randomly allocated to one of 3 functional groups: information-based (n = 183), supportive (n = 3994), or personalized-supportive (n = 3935). Both supportive sites included tools, such as a weight tracker, meal planner, and social networking platform. The personalized-supportive site included a meal planner that offered recommendations that were personalized using an algorithm based on a user’s preferences for certain foods. Dietary and activity information were constant across sites, based on an existing and tested 12-week weight loss program (the Total Wellbeing Diet). Before and/or after the intervention, participants completed demographic (including self-reported weight), behavioral, and evaluation questionnaires online. Usage of the website and features was objectively recorded. All screening and data collection procedures were performed online with no face-to-face contact.

Results

Across all 3 groups, attrition was high at around 40% in the first week and 20% of the remaining participants each week. Retention was higher for the supportive sites compared to the information-based site only at week 12 (P = .01). The average number of days that each site was used varied significantly (P = .02) and was higher for the supportive site at 5.96 (SD 11.36) and personalized-supportive site at 5.50 (SD 10.35), relative to the information-based site at 3.43 (SD 4.28). In total, 435 participants provided a valid final weight at the 12-week follow-up. Intention-to-treat analyses (using multiple imputations) revealed that there were no statistically significant differences in weight loss between sites (P = .42). On average, participants lost 2.76% (SE 0.32%) of their initial body weight, with 23.7% (SE 3.7%) losing 5% or more of their initial weight. Within supportive conditions, the level of use of the online weight tracker was predictive of weight loss (model estimate = 0.34, P < .001). Age (model estimate = 0.04, P < .001) and initial BMI (model estimate = -0.03, P < .002) were associated with frequency of use of the weight tracker.

Conclusions

Relative to a static control, inclusion of social networking features and personalized meal planning recommendations in a web-based weight loss program did not demonstrate additive effects for user weight loss or retention. These features did, however, increase the average number of days that a user engaged with the system. For users of the supportive websites, greater use of the weight tracker tool was associated with greater weight loss.

Continuous evolution of statistical estimators for optimal decision-making

In many everyday situations, humans must make precise decisions in the presence of uncertain sensory information. For example, when asked to combine information from multiple sources we often assign greater weight to the more reliable information. It has been proposed that statistical-optimality often observed in human perception and decision-making requires that humans have access to the uncertainty of both their senses and their decisions. However, the mechanisms underlying the processes of uncertainty estimation remain largely unexplored. In this paper we introduce a novel visual tracking experiment that requires subjects to continuously report their evolving perception of the mean and uncertainty of noisy visual cues over time. We show that subjects accumulate sensory information over the course of a trial to form a continuous estimate of the mean, hindered only by natural kinematic constraints (sensorimotor latency etc.). Furthermore, subjects have access to a measure of their continuous objective uncertainty, rapidly acquired from sensory information available within a trial, but limited by natural kinematic constraints and a conservative margin for error. Our results provide the first direct evidence of the continuous mean and uncertainty estimation mechanisms in humans that may underlie optimal decision making.

Butyrate esterified to starch is released in the human gastrointestinal tract

BACKGROUND

Short-chain fatty acids (SCFAs) maintain human colonic function and may help prevent colonic disease. A study with ileostomists showed that starches acylated with specific SCFAs largely survive passage through the small intestine, but the percentage released in the colon has not been established.

OBJECTIVE

The objective was to determine the percentage of ingested esterified butyrate released in the human gastrointestinal tract.

DESIGN

The study was a randomized, crossover, controlled trial consisting of baseline and four 2-wk periods during which 16 volunteers consumed diets low in resistant starch plus 20 and 40 g cooked high-amylose maize starch (HAMS: HAMS20 or HAMS40) or butyrylated HAMS (HAMSB20 or HAMSB40) daily. HAMSB20 contained 31.8 mmol esterified butyrate. Complete 48-h fecal collections were made on days 2-3 and 12-13 of each period.

RESULTS

Free fecal butyrate concentrations were higher after HAMSB40 than after HAMSB20 (P < 0.005) and HAMS (P < 0.0001) and higher than baseline data (P < 0.0001). Fecal esterified butyrate concentrations were highest in the HAMSB40 (days 12-13; P < 0.0001) group, and concentrations in the HAMSB40 (days 2-3) and HAMSB20 groups were higher than those in the HAMS groups and those at baseline (P < 0.0001). Ingestion of HAMSB20 and HAMSB40 resulted in the release of 26.8 ± 1.0 and 50.2 ± 2.4 mmol butyrate/d (days 12-13) (84.2 ± 3.0% and 79.0 ± 3.1% of total ingested esterified butyrate), respectively, in the gastrointestinal tract. By calculation, ∼57.2% of ingested esterified butyrate was released in the colon. Microbial analysis showed that this release was probably facilitated mainly by Parabacteroides distasonis, which increased in abundance with HAMSB40 (days 12-13) (P < 0.001).

CONCLUSIONS

This study shows that cooked butyrylated starch delivers esterified butyrate to the human colon effectively and has the potential to improve human bowel health. This trial is registered in the Australian Clinical Trials Registry as ACTRN012606000398505.

The role of feed-forward and feedback processes for closed-loop prosthesis control

Background

It is widely believed that both feed-forward and feed-back mechanisms are required for successful object manipulation. Open-loop upper-limb prosthesis wearers receive no tactile feedback, which may be the cause of their limited dexterity and compromised grip force control. In this paper we ask whether observed prosthesis control impairments are due to lack of feedback or due to inadequate feed-forward control.

Methods

Healthy subjects were fitted with a closed-loop robotic hand and instructed to grasp and lift objects of different weights as we recorded trajectories and force profiles. We conducted three experiments under different feed-forward and feed-back configurations to elucidate the role of tactile feedback (i) in ideal conditions, (ii) under sensory deprivation, and (iii) under feed-forward uncertainty.

Results

(i) We found that subjects formed economical grasps in ideal conditions. (ii) To our surprise, this ability was preserved even when visual and tactile feedback were removed. (iii) When we introduced uncertainty into the hand controller performance degraded significantly in the absence of either visual or tactile feedback. Greatest performance was achieved when both sources of feedback were present.

Conclusions

We have introduced a novel method to understand the cognitive processes underlying grasping and lifting. We have shown quantitatively that tactile feedback can significantly improve performance in the presence of feed-forward uncertainty. However, our results indicate that feed-forward and feed-back mechanisms serve complementary roles, suggesting that to improve on the state-of-the-art in prosthetic hands we must develop prostheses that empower users to correct for the inevitable uncertainty in their feed-forward control.

The role of hippocampal subregions in memory for stimulus associations

The hippocampus is hypothesised to be critical for episodic memory in humans and episodic-like memory in animals. Human data regarding the roles of the various subregional networks within the hippocampus is difficult to obtain. In this article we examine the current rodent literature on episodic-like memory and associative recognition and review the roles of the hippocampal subregions in these behavioural tasks. We focus on the large amount of recent data reporting roles for CA3 and CA1 in allocentric spatial and temporal associative memory respectively. Our own recent data are then presented detailing critical roles for CA3 and CA1 in an associative recognition task which does not require allocentric spatial or temporal processing. These data support more generic roles for CA3 and CA1 in episodic-like memory, based on anatomical and theoretical literature on hippocampal function. We also present a novel analysis of our data in which we suggest that the encoding of object, place and context information is unaffected by lesions of the hippocampus and therefore infer that it may be the storage or retrieval phase of this associative memory which is critically dependent on hippocampal function. In conclusion however, more specific anatomically and temporally controlled methods are needed to fully define the role of hippocampal subregions in episodic-like memory.

An a posteriori strategy for enhancing gene discovery in anonymous cDNA microarray experiments

MOTIVATION

Because of the high cost of sequencing, the bulk of gene discovery is performed using anonymous cDNA microarrays. Though the clones on such arrays are easier and cheaper to construct and utilize than unigene and oligonucleotide arrays, they are there in proportion to their corresponding gene expression activity in the tissue being examined. The associated redundancy will be there in any pool of possibly interesting differentially expressed clones identified in a microarray experiment for subsequent sequencing and investigation. An a posteriori sampling strategy is proposed to enhance gene discovery by reducing the impact of the redundancy in the identified pool.

RESULTS

The proposed strategy exploits the fact that individual genes that are highly expressed in a tissue are more likely to be present as a number of spots in an anonymous library and, as a direct consequence, are also likely to give higher fluorescence intensity responses when present in a probe in a cDNA microarray experiment. Consequently, spots that respond with low intensities will have a lower redundancy and so should be sequenced in preference to those with the highest intensities. The proposed method, which formalizes how the fluorescence intensity of a spot should be assessed, is validated using actual microarray data, where the sequences of all the clones in the identified pool had been previously determined. For such validations, the concept of a repeat plot is introduced. It is also utilized to visualize and examine different measures for the characterization of fluorescence intensity. In addition, as confirmatory evidence, sequencing from the lowest to the highest intensities in a pool, with all the sequences known, is compared graphically with their random sequencing. The results establish that, in general, the opportunity for gene discovery is enhanced by avoiding the pooling of different biological libraries (because their construction will have involved different hybridization episodes) and concentrating on the clones with lower fluorescence intensities.

The relationship between playfulness and coping in preschool children: a pilot study

OBJECTIVE

Effective play and coping skills may be important determinants of children's adaptive behavior. Play and coping have undergone extensive individual study; however, these two variables have not been explored in relationship to each other.

METHOD

The play behaviors of 19 randomly selected preschool children were rated by researchers using The Test of Playfulness. The children's coping skills were rated by their teachers with the Coping Inventory.

RESULTS

A positive, significant correlation was found between children's level of playfulness and their coping skills. Overall, girls were rated as more playful than boys and scored higher in coping skills. Younger children (36-47 months of age) were rated as better players and copers than older children (47-57 months of age).

CONCLUSION

This pilot study supports occupational therapy intervention in children's play environments and playful interactions as a way of influencing their adaptability in all life skills.

The syndrome of Karl Ludwig Kahlbaum

Karl Ludwig Kahlbaum was the first to describe catatonia in 1868. There has been a tendency to consider catatonia as a psychiatric disease despite many case reports demonstrating a wide range of medical and neurological as well as psychiatric causes. We present our accumulated experience of the catatonic syndrome. Most cases (36%) were associated with affective illness but five cases (20%) had a defined organic disorder. A significant minority had no identifiable cause and there was only one case of schizophrenia. The idiopathic and affective groups had a high incidence of recurrent catatonic episodes and many had a family history of a similar problem. The prognosis was excellent, except for the few patients who presented with the acute and rapidly progressive form of the syndrome which led to acute renal failure.

Improving Productivity: A Team Building Approach

The project which this report outlines took place in a manufacturing plant of a medium sized company. The plant employed approximately 1,200 people operating on a four shift manufacturing system. They produced, by continuous process, a variety of similar consumer products. The project lasted approximately nine months. This report outlines the course of the project and its final outcome. The lessons that were learnt from this project have been put together in the form of a conclusion to this report.