External workload and cognitive performance of a tactical military scenario-based field exercise.

INTRODUCTION: Military personnel must manage a multitude of competing physiological and cognitive stressors while maintaining high levels of performance. Quantifying the external workload and cognitive demands of tactical military field exercises closely simulating operational environments, will provide a better understanding of stressors placed on personnel to inform evidence-based interventions. METHODS: Thirty-one soldiers completing a dismounted 48 hours tactical field exercise, participated in the study. External workload was quantified using a wrist-worn triaxial accelerometer, with cognitive function (Go-/No-Go, N-back, psychomotor vigilance task and subjective workload ratings (NASA-TLX) assessed pre-exercise, mid-exercise and postexercise. Physical activity was described using Euclidian Norm Minus One (mg), with moderate vigorous physical activity (MVPA) and sedentary light physical activity (SLPA) as ≥ or <113 mg, respectively. Changes in general cognitive performance (total accuracy-speed trade-off (ASTO) % change) and function outcome variables (overall mean reaction time, ASTO and number of correct and missed responses) were calculated for each assessment from pre-exercise, to mid-exercise and postexercise. RESULTS: For the exercise duration (50:12±02:06 hh:mm) participants spent more time completing SLPA compared with MVPA (1932±234 vs 1074±194 min; p<0.001), equating to 33% of the time spent completing MVPA. Overall cognitive performance decreased over the exercise (pre-to-post: -249). However, the largest decrement was observed pre-to-mid (-168). Perceived mental demand associated with the cognitive assessments significantly increased over the duration of the exercise (pre-: 33; mid-: 38 and post-: 51; χ2 F(2) = 26.7, p = <0.001, W=0.477) which could suggest that participants were able to attenuate a further decline in cognitive performance by investing more effort/mental resources when completing assessments. CONCLUSION: The study successfully quantified the physical activity, and subsequent impact on cognitive function, in soldiers completing a 48 hours tactical field exercise. Further research is needed to better understand how physiological stressors interact with cognitive function during military operations.

A comparison of physical performance during one- and two-person simulated casualty drags.

The ability to drag a casualty to safety is critical for numerous physically demanding occupations. This study aimed to establish whether the pulling forces during a one-person 55 kg simulated casualty drag is representative of a two-person 110 kg drag. Twenty men completed up to 12 × 20m simulated casualty drags using a drag bag (55/110 kg) on a grassed sports pitch, with completion times and forces exerted measured. Completion time for the one-person 55 and 110 kg drags were 9.56 ± 1.18s and 27.08 ± 7.71s. Completion time for the 110 kg two-person drags for forwards and backwards iterations were 8.36 ± 1.23s and 11.04 ± 1.11s. The average individual force exerted during the one-person 55 kg drag was equivalent to the average individual contribution during the two-person 110 kg drag (t(16) = 3.3780, p < 0.001); suggesting a one-person 55 kg simulated casualty drag is representative of the individual contribution to a two-person 110 kg simulated casualty drag. Individual contributions can however vary during two-person simulated casualty drags.

Changes in physical performance during British Army Junior Entry, British Army Standard Entry and Royal Air Force Basic Training.

INTRODUCTION: The purpose was to quantify physical performance in men and women during British Army Junior Entry (Army-JE), British Army Standard Entry (Army-SE) and Royal Air Force (RAF) basic training (BT). DESIGN: Prospective longitudinal study. METHODS: 381 participants ((339 men and 42 women) n=141 Army-JE, n=132 Army-SE, n=108 RAF) completed a 2 km run, medicine ball throw (MBT) and isometric mid-thigh pull (MTP), pre-BT and post-BT. To examine changes in pre-BT to post-BT physical test performance, for each course, paired Student t-test and Wilcoxon test were applied to normally and non-normally distributed data, respectively, with effect sizes reported as Cohen's D and with rank biserial correlations, respectively. A one-way between-subjects analysis of variance (ANOVA) (or Welch ANOVA for non-normally distributed data) compared performance between quartiles based on test performance pre-BT. Where the main tests statistic, p value and effect sizes identified likely effect of quartile, post hoc comparisons were made using Games-Howell tests with Tukey's p value. Data are presented as mean±SD, with statistical significance set at p<0.05. RESULTS: During BT, 2 km run time improved by 13±46 s (-2.1%±8.1%), 30±64 s (-4.8%±12.3%) and 24±27 s (-4.5%±5.1%) for Army-JE, Army-SE and RAF, respectively (all p<0.005). MBT distance increased by 0.27±0.28 m (6.8%±7.0%) for Army-JE (p<0.001) and 0.07±0.46 m (2.3%±10.9%) for Army-SE (p=0.040), but decreased by 0.08±0.27 m (-1.4%±6.0%) for RAF (p=0.002). MTP force increased by 80±281 n (10.8%±27.6%) for Army-JE (p<0.001) and did not change for Army-SE (-36±295 n, -0.7%±20.6%, p=0.144) or RAF (-9±208 n, 1.0±17.0, p=0.603). For all tests and cohorts, participants in the lowest quartile of pre-BT performance scores demonstrated greater improvements, compared with participants in the highest quartile (except Army-JE MBT, ∆% change similar between all quartiles). CONCLUSIONS: Changes in physical performance were observed for the three fitness tests following the different BT courses, and recruits with the lowest strength and aerobic fitness experienced greatest improvements.

Sacrococcygeal dimensions and curvature are associated with resection quality in rectal cancer excision.

BACKGROUND: Technical factors affect oncologic outcomes in rectal cancer surgery. The anatomy of the bony pelvis can affect technical aspects of surgery, but is seldom considered preoperatively. We performed a morphometric analysis of the bony pelvis in patients having rectal cancer resection to assess its effect on surgical specimen quality. METHODS: We performed a retrospective analysis of a prospectively maintained database of patients who had resection for rectal cancer from January 2014 to December 2017. Preoperative magnetic resonance imaging (MRI) and computed tomography (CT) images were accessed and measurements of sacrococcygeal distance, sacrococcygeal recess depth/area, sacrococcygeal angulation, anteroposterior pelvic inlet/outlet, pubic height and interspinous distance were made. Outcome measures included anatomical variation, operating time and mesorectal specimen grade. In patients having extra-levator abdominoperineal excision (eLAPE) with coccygectomy, the completeness of coccygeal resection was assessed by postoperative CT scan. Data were analysed using binomial and multinomial logistic regression and linear regression. RESULTS: One hundred and twenty-two consecutive rectal cancer resections were performed (39 open, 42 laparoscopic, 12 laparoscopic-converted and 29 robotic). The median age was 72 years (range: 29-88 years). The male:female ratio was 83:39. Eighty-one patients had anterior resection, 8 had low Hartmann's resection and 32 had APE. Of those who had APE, 21 had eLAPE (all with coccygectomy). Females had a larger pelvic inlet (female: 124.9 mm, male: 114.9 mm), interspinous diameter(female:112.8 mm, male:97.6 mm), sacrococcygeal depth (female:42.6 mm, 39.35 mm) and sacrococcygeal area recess than males (female: 3697 mm2, male: 3481.5 mm2). Males had a greater pubic height (female: 51.8 mm, male: 54.05 mm) and greater sacrococcygeal distance (female: 116.7 mm, male: 123.65 mm) than females. In patients having anterior resection, tumour distance from the anal verge (p = 0.004), sacrococcygeal distance (p = 0.006) and sacrococcygeal curvature (p = 0.002) were associated with specimen quality. In patients who had eLAPE, median preoperative coccygeal length was 41 mm (IQR: 35.1-45.5). The median length of coccygeal resection was 9 mm (IQR: 1-17.45 mm). The median length of coccyx remaining postoperatively was 33 mm (IQR: 21.35-39 mm). CONCLUSIONS: Sacrococcygeal curvature and distance as well as tumour distance from the anal margin were associated with specimen quality in anterior resection. Coccygectomy was not performed as completely as surgeons thought. Surgeons should include sacrococcygeal bony anatomy in rectal cancer surgical planning to potentially improve outcomes in both anterior resection and eLAPE approaches.

Awareness of surgical expenditure amongst UK trainees and consultants: A questionnaire study.

INTRODUCTION: Limited knowledge of surgical device and service costs restricts a surgeon's ability to make cost efficient choices and contribute to the efficiency savings required by the NHS to reduce the financial deficit. This study aims to assess how aware surgeons are of surgical equipment and regularly used services. METHODS: A single sided hard copy questionnaire asking for the estimate cost of 24 surgical devices/services was handed out to individuals at two separate UK annual conferences. Items and services which are regularly used and/or clinically significant were selected and, where possible, alternatives to those items were included for comparison. Participants were also asked for their grade and specialty. An estimate was deemed correct if it was within 20% of the actual cost. Planned subgroup analyses for grade and specialty were performed. RESULTS: The 143 participants consisted of 23 (16%) consultants, 39 (27%) registrars, 33 (23%) SHOs and 48 (34%) foundation doctors. Of the 95 participants who were SHO grade or more senior, 67 (71%) work within general surgery. Across all items, only 9.6% of estimates were correct. There was no statistically significant difference between training levels (consultant 11.5%, registrar 10.1%, SHO 8.6%, foundation 8.9%; p = 0.253). Participants were significantly less successful in correctly estimating the cost of high value (>£150 [USD $198; EUR €175]) items (8.5% vs. 11.1%); p = 0.011, and the cost of devices as compared to the cost of services (7.4% vs. 15.0%); p = 0.001. CONCLUSION: Surgeons across all grades and specialties have poor knowledge of device and service costs. It is important that this improves in order to allow surgeons to make a meaningful contribution to NHS efficiency savings by making informed decisions about their use of devices and services.

1.5mile run time and body mass predict 8mile loaded march performance, irrespective of sex.

OBJECTIVES: To develop a statistical model to predict 8mile Loaded March (LM) performance and quantify differences in physical characteristics for men and women British Army Personnel. DESIGN: 135 trained soldiers (87 men; 48 women) completed two sessions, seven days apart. METHODS: Session 1: Participants' stature, body mass, Fat Free Mass (FFM) [by dual-energy X-ray absorptiometry], Single Lift (SL), Water Can Carry (WCC), and 1.5mile run performance were measured. Session 2: Participants completed an 8mile LM, carrying 25kg (4miles paced and 4miles individual best effort). Sex differences were compared using independent samples t-tests and 8mile LM performance time was predicted using various multiple linear regression analysis: hierarchical forced entry multiple ordinary least squares, principal component and ordinary least products. RESULTS: A combination of 1.5mile run time and body mass were the strongest predictors of 8mile LM time (R2=0.71; SEE=4.17min; p<0.001). Including stature, FFM, sex, SL score, or WCC score did not further improve predictions (p>0.05). Compared to women, men had faster mean 1.5mile run and LM times, greater body mass and total FFM and higher SL and WCC scores (p<0.001), however some women outperformed men. CONCLUSION: 1.5mile run time and body mass predict 8mile LM performance with no further improvement gained in the model by including sex as a variable.

Cancer patient experience with navigation service in an urban hospital setting: a qualitative study.

Cancer patient navigators are increasingly present on the oncology health care team. The positive impact of navigation on cancer care is recognised, yet a clear understanding of what the patient navigator does and how he/she executes the role continues to emerge. This study aimed to understand cancer patients' perceptions of, and experiences with patient navigation, exploring how navigation may enhance the patient experience in an urban hospital setting where patients with varying needs are treated. A qualitative study using a constructionist approach was conducted. Fifteen colorectal cancer patients participated in semi-structured telephone interviews. Data were analyzed inductively and iteratively. Findings provide insight into two central aspects of cancer navigation: navigation as patient-centred coordination and explanation of clinical care, and navigation as individualised, holistic support. Within these themes, the key benefits of navigation from the patients' perspective were demystifying the system; ensuring comprehension, managing expectations; and, delivering patient-centred care. The navigator provided individualised and extended family support; a holistic approach; and, addressed emotional and psychological needs. These findings provide a means to operationalise and validate an emerging role description and competency framework for the cancer navigator who must identify and adapt to patients' varying needs throughout the cancer care continuum.

Physical employment standards for U.K. fire and rescue service personnel.

BACKGROUND: Evidence-based physical employment standards are vital for recruiting, training and maintaining the operational effectiveness of personnel in physically demanding occupations. AIMS: (i) Develop criterion tests for in-service physical assessment, which simulate the role-related physical demands of UK fire and rescue service (UK FRS) personnel. (ii) Develop practical physical selection tests for FRS applicants. (iii) Evaluate the validity of the selection tests to predict criterion test performance. METHODS: Stage 1: we conducted a physical demands analysis involving seven workshops and an expert panel to document the key physical tasks required of UK FRS personnel and to develop 'criterion' and 'selection' tests. Stage 2: we measured the performance of 137 trainee and 50 trained UK FRS personnel on selection, criterion and 'field' measures of aerobic power, strength and body size. Statistical models were developed to predict criterion test performance. Stage 3: matter experts derived minimum performance standards. RESULTS: We developed single person simulations of the key physical tasks required of UK FRS personnel as criterion and selection tests (rural fire, domestic fire, ladder lift, ladder extension, ladder climb, pump assembly, enclosed space search). Selection tests were marginally stronger predictors of criterion test performance (r = 0.88-0.94, 95% Limits of Agreement [LoA] 7.6-14.0%) than field test scores (r = 0.84-0.94, 95% LoA 8.0-19.8%) and offered greater face and content validity and more practical implementation. CONCLUSIONS: This study outlines the development of role-related, gender-free physical employment tests for the UK FRS, which conform to equal opportunities law.

Insulated skin temperature as a measure of core body temperature for individuals wearing CBRN protective clothing.

This study assessed the validity of insulated skin temperature (Tis) to predict rectal temperature (Tre) for use as a non-invasive measurement of thermal strain to reduce the risk of heat illness for emergency service personnel. Volunteers from the Police, Fire and Rescue, and Ambulance Services performed role-related tasks in hot (30 °C) and neutral (18 °C) conditions, wearing service specific personal protective equipment. Insulated skin temperature and micro climate temperature (Tmc) predicted Tre with an adjusted r(2) = 0.87 and standard error of the estimate (SEE) of 0.19 °C. A bootstrap validation of the equation resulted in an adjusted r(2) = 0.85 and SEE = 0.20 °C. Taking into account the 0.20 °C error, the prediction of Tre resulted in a sensitivity and specificity of 100% and 91%, respectively. Insulated skin temperature and Tmc can be used in a model to predict Tre in emergency service personnel wearing CBRN protective clothing with an SEE of 0.2 °C. However, the model is only valid for Tis over 36.5 °C, above which thermal stability is reached between the core and the skin.

Intra- and interday reliability of voluntary and electrically stimulated isometric contractions of the quadriceps femoris.

The reliability of voluntary and electrically stimulated isometric contractions of m. quadriceps femoris of male participants (n=10; age 30±8years; height 1.79±0.05m; body mass 79.4±8.3kg) was investigated using ratio limits of agreement (LoA) on a time scale common to examine recovery from muscle damaging exercise. No systematic changes in reliability occurred over time (baseline versus 2, 24, 48, and 72h). Maximal voluntary contraction (MVC) and interpolated twitch technique (ITT) showed no mean bias (P>0.05) with 95% LoA of ±12.7 and ±5.4, respectively. Resting twitch and potentiated doublet peak force showed no mean bias (P>0.05). However, 95% LoA were smaller for the doublet (±13.9) than the twitch (±32.0). Twitch and doublet rates showed similar trends. Ratio of low (20Hz) to high (50Hz) frequency forces showed no mean bias (P>0.05) and 95% LoA of (±9.2). However, there was significant mean bias (P<0.05) and wider 95% LoA for peak force, contraction and relaxation parameters of the low and high frequency forces. In conclusion, MVC, ITT, potentiated doublet and the ratio of low to high frequency forces are recommended to most reliably examine functional muscle recovery between 2 and 72h after damaging exercise.

An in vitro investigation of the erosive potential of smoothies.

INTRODUCTION: Recent health promotion campaigns have encouraged the public to consume at least five portions of fruit and vegetables per day. Many see consuming fruit smoothies as a way of achieving this. OBJECTIVE: To ascertain the potential or otherwise for fruit smoothies to bring about dental erosion. DESIGN: Laboratory study.Method This was an in vitro investigation in which five varieties of shop bought fruit smoothies, including a 'thickie' were investigated, with respect to their initial pH, titratable acidity and effect upon exposure to the surface microhardness and profile of extracted human teeth. In addition their performance was compared to negative (Volvic(™) water) and positive (orange juice) control drinks as well as a homemade smoothie, based upon the recipe of one of the commercially bought drinks, from which ingredient omissions were made. RESULTS: The majority of the drinks investigated had a baseline pH below the critical pH of enamel (5.5) and required comparable volumes of 0.1M NaOH to raise their pH to neutrality as the positive control. Only two drinks (Volvic(™) still mineral water, the negative control, and the yoghurt, vanilla bean and honey 'thickie') displayed a higher pH, though to neutralise the thickie, a lesser quantity of alkali addition was required. The immersion of the tooth samples in the drinks brought about reductions in their surface hardness (expressed as a percentage change of median hardness) but these were only significant (p <0.001) for the cranberry, blueberry and cherry fruit smoothie and homemade strawberry and banana fruit smoothie. There was no reduction in surface hardness in the case of the teeth immersed in the thickie. Omission of certain ingredients from the homemade smoothie affected the magnitude of surface hardness reductions seen. With regard to the loss of surface contour of the tooth samples following immersion in the drinks, as assessed by depth loss, there were significant differences between the drinks (p = 0.0064) with the thickie and negative control not causing depth loss and the kiwi, apple and lime smoothie producing most depth loss (28.26 (5.45) µm). CONCLUSIONS: Within the limitations of this study some fruit smoothies have the potential to bring about dental erosion if consumed irresponsibly. This can be influenced by ingredient variations. In order to minimise the risk of developing dental erosion, without removing the claimed nutritional benefits of their consumption, their consumption should be confined to mealtimes.

Physical demands of firefighter search and rescue in ambient environmental conditions.

This study investigated the physiological responses and limitations to a simulated search and rescue scenario in a high-rise building under ambient conditions. Sixteen firefighters performed the scenario under four conditions: standard duration breathing apparatus (SDBA) and 45 mm hose; extended duration breathing apparatus (EDBA) and 45 mm hose; SDBA and 70 mm hose; EDBA and 70 mm hose. Core temperature, skin temperature and heart rate were monitored. In four of 32 trials the casualty was rescued; the remainder of the trials were terminated for safety, high core temperature or shortage of air. Final core temperature and heart rate were higher in the EDBA (39.1 degrees C; 72% heart rate reserve (HRR)) than SDBA conditions (38.6 degrees C; 67%HRR). No differences were observed between hose sizes. The scenario proved too onerous to complete successfully in the majority of cases. Replacing SDBA with EDBA eliminates air supply as a limiting factor, but brings with it challenges of managing thermal strain.

Segmentation of mammograms using multiple linked self-organizing neural networks.

A possible first stage in the analysis of the mammographic scene is its segmentation into four major components: background (the nonbreast area), pectoral muscle, fibroglandular region (parenchyma), and adipose region. An algorithm has been developed for this task. It is based on the classification of a feature vector constructed from statistical measures of texture calculated at two window sizes. Separate self-organizing neural networks are trained on sample data taken from each of the four regions. The feature vectors from the entire mammogram are then classified with the trained networks linked via a decision logic. To overcome the variability of texture between mammograms the algorithm uses data from a mammogram to classify itself in a staged approach consisting of several binary decisions. The training regions for each successive stage are determined from geometric information produced by the previous stages. The dataset in the study consisted of thirty (fifteen pairs) digitized normal mammograms of variable radiographic appearance. As a measure of performance, the outlines of the parenchyma were compared to those drawn by a radiologist experienced in reading mammograms. Comparison of the areas and perimeters generated by the human and computer observers gives a relationship with correlation coefficients of 0.74 and 0.59 for each measure, respectively. The overlapping areas of the parenchymas segmented by the observers normalized by the combined area was also calculated for each case. The mean and standard deviation of this measure was 0.69 +/- 0.12.