The use of intrapartum ultrasound in operative vaginal birth: a retrospective cohort study.

BACKGROUND: Poor outcomes from operative vaginal birth have been associated with failure to recognize malposition, breakdown in interdisciplinary communication, and deviation from accepted guidelines. We recently implemented a safety bundle including routine intrapartum ultrasound and a structured time-out and procedural checklist aiming to reduce maternal and perinatal morbidity from operative vaginal birth. OBJECTIVE: This study aimed to compare births where intrapartum ultrasound was used and those where it was not used during a safety bundle implementation period at Monash Health. STUDY DESIGN: We performed a retrospective cohort study at Monash Health during the transitional phase of implementing an operative vaginal birth safety bundle. We studied all women with operative vaginal birth and fully dilated cesarean delivery with a singleton cephalic term fetus. We compared births for which intrapartum ultrasound was used and those for which it was not. The primary outcome was neonates delivered in an unexpected position. Neonatal and maternal morbidity were also assessed, including a neonatal composite of Apgar score <7 at 5 minutes, cord lactate >8 mmol/L, need for resuscitation, significant birth trauma, or neonatal intensive care unit admission. To control for confounding by indication, we estimated propensity scores for the probability of using intrapartum ultrasound for each case based on maternal and labor characteristics, and adjusted the effect estimates for the propensity scores using multivariable logistic regression models. RESULTS: From August 2022 to July 2023, there were 1205 operative vaginal births or fully dilated cesarean deliveries at Monash Health, including 743 (61.7%) forceps, 346 (28.7%) vacuum, and 116 (9.6%) fully dilated cesarean deliveries. Over this time, we observed increased uptake of intrapartum ultrasound from 26% in August 2022 to 60% (P<.001) in July 2023, of the time-out from 21% to 58% (P<.001), and the checklist from 33% to 80% (P<.001) of operative second-stage births. Among the births where intrapartum ultrasound was used (n=509), compared with those where it was not (n=696), there were significantly more forceps births (67% vs 58%; adjusted odds ratio, 1.35; 95% confidence interval, 1.05-1.74; P=.021) and a reduction in vacuum births (24% vs 32%; adjusted odds ratio, 0.77; 95% confidence interval, 0.58-1.01; P=.059). There were no significant differences in fully dilated cesarean delivery or maternal morbidity. Intrapartum ultrasound use was associated with significantly fewer infants being delivered in an unexpected position (0.2% vs 2.2%; adjusted odds ratio, 0.08; 95% confidence interval, 0.00-0.44; P=.019) and a significant reduction in composite neonatal morbidity (22% vs 25%; adjusted odds ratio, 0.73; 95% confidence interval, 0.54-0.97; P=.031). CONCLUSION: During the implementation of a safety bundle, the use of ultrasound before operative vaginal birth was associated with fewer infants delivered in an unexpected position and reduced neonatal morbidity.

Characterization of the diffusion signal of breast tissues using multi-exponential models.

PURPOSE: Restriction spectrum imaging (RSI) decomposes the diffusion-weighted MRI signal into separate components of known apparent diffusion coefficients (ADCs). The number of diffusion components and optimal ADCs for RSI are organ-specific and determined empirically. The purpose of this work was to determine the RSI model for breast tissues. METHODS: The diffusion-weighted MRI signal was described using a linear combination of multiple exponential components. A set of ADC values was estimated to fit voxels in cancer and control ROIs. Later, the signal contributions of each diffusion component were estimated using these fixed ADC values. Relative-fitting residuals and Bayesian information criterion were assessed. Contrast-to-noise ratio between cancer and fibroglandular tissue in RSI-derived signal contribution maps was compared to DCE imaging. RESULTS: A total of 74 women with breast cancer were scanned at 3.0 Tesla MRI. The fitting residuals of conventional ADC and Bayesian information criterion suggest that a 3-component model improves the characterization of the diffusion signal over a biexponential model. Estimated ADCs of triexponential model were D1,3 = 0, D2,3 = 1.5 × 10-3 , and D3,3 = 10.8 × 10-3 mm2 /s. The RSI-derived signal contributions of the slower diffusion components were larger in tumors than in fibroglandular tissues. Further, the contrast-to-noise and specificity at 80% sensitivity of DCE and a subset of RSI-derived maps were equivalent. CONCLUSION: Breast diffusion-weighted MRI signal was best described using a triexponential model. Tumor conspicuity in breast RSI model is comparable to that of DCE without the use of exogenous contrast. These data may be used as differential features between healthy and malignant breast tissues.

Understanding diffusion-weighted MRI analysis: Repeatability and performance of diffusion models in a benign breast lesion cohort.

Diffusion-weighted MRI (DWI) is an important tool for oncology research, with great clinical potential for the classification and monitoring of breast lesions. The utility of parameters derived from DWI, however, is influenced by specific analysis choices. The purpose of this study was to critically evaluate repeatability and curve-fitting performance of common DWI signal representations, for a prospective cohort of patients with benign breast lesions. Twenty informed, consented patients with confirmed benign breast lesions underwent repeated DWI (3 T) using: sagittal single-shot spin-echo echo planar imaging, bipolar encoding, TR/TE: 11,600/86 ms, FOV: 180 x 180 mm, matrix: 90 x 90, slices: 60 x 2.5 mm, iPAT: GRAPPA 2, fat suppression, and 13 b-values: 0-700 s/mm2 . A phase-reversed scan (b = 0 s/mm2 ) was acquired for distortion correction. Voxel-wise repeat-measures coefficients of variation (CoVs) were derived for monoexponential (apparent diffusion coefficient [ADC]), biexponential (intravoxel incoherent motion: f, D, D*) and stretched exponential (α, DDC) across the parameter histograms for lesion regions of interest (ROIs). Goodness-of-fit for each representation was assessed by Bayesian information criterion. The volume of interest (VOI) definition was repeatable (CoV 13.9%). Within lesions, and across both visits and the cohort, there was no dominant best-fit model, with all representations giving the best fit for a fraction of the voxels. Diffusivity measures from the signal representations (ADC, D, DDC) all showed good repeatability (CoV < 10%), whereas parameters associated with pseudodiffusion (f, D*) performed poorly (CoV > 50%). The stretching exponent α was repeatable (CoV < 12%). This pattern of repeatability was consistent over the central part of the parameter percentiles. Assumptions often made in diffusion studies about analysis choices will influence the detectability of changes, potentially obscuring useful information. No single signal representation prevails within or across lesions, or across repeated visits; parameter robustness is therefore a critical consideration. Our results suggest that stretched exponential representation is more repeatable than biexponential, with pseudodiffusion parameters unlikely to provide clinically useful biomarkers.

Analysis of Renal Diffusion-Weighted Imaging (DWI) Using Apparent Diffusion Coefficient (ADC) and Intravoxel Incoherent Motion (IVIM) Models.

Analysis of renal diffusion-weighted imaging (DWI) data to derive markers of tissue properties requires careful consideration of the type, extent, and limitations of the acquired data. Alongside data quality and general suitability for quantitative analysis, choice of diffusion model, fitting algorithm, and processing steps can have consequences for the precision, accuracy, and reliability of derived diffusion parameters. Here we introduce and discuss important steps for diffusion-weighted image processing, and in particular give example analysis protocols and pseudo-code for analysis using the apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) models. Following an overview of general principles, we provide details of optional steps, and steps for validation of results. Illustrative examples are provided, together with extensive notes discussing wider context of individual steps, and notes on potential pitfalls.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concepts and experimental procedure.

Recommendations for Preclinical Renal MRI: A Comprehensive Open-Access Protocol Collection to Improve Training, Reproducibility, and Comparability of Studies.

Renal MRI holds incredible promise for making a quantum leap in improving diagnosis and care of patients with a multitude of diseases, by moving beyond the limitations and restrictions of current routine clinical practice. Clinical and preclinical renal MRI is advancing with ever increasing rapidity, and yet, aside from a few examples of renal MRI in routine use, it is still not good enough. Several roadblocks are still delaying the pace of progress, particularly inefficient education of renal MR researchers, and lack of harmonization of approaches that limits the sharing of results among multiple research groups.Here we aim to address these limitations for preclinical renal MRI (predominantly in small animals), by providing a comprehensive collection of more than 40 publications that will serve as a foundational resource for preclinical renal MRI studies. This includes chapters describing the fundamental principles underlying a variety of renal MRI methods, step-by-step protocols for executing renal MRI studies, and detailed guides for data analysis. This collection will serve as a crucial part of a roadmap toward conducting renal MRI studies in a robust and reproducible way, that will promote the standardization and sharing of data.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.

Renal Diffusion-Weighted Imaging (DWI) for Apparent Diffusion Coefficient (ADC), Intravoxel Incoherent Motion (IVIM), and Diffusion Tensor Imaging (DTI): Basic Concepts.

The specialized function of the kidney is reflected in its unique structure, characterized by juxtaposition of disorganized and ordered elements, including renal glomerula, capillaries, and tubules. The key role of the kidney in blood filtration, and changes in filtration rate and blood flow associated with pathological conditions, make it possible to investigate kidney function using the motion of water molecules in renal tissue. Diffusion-weighted imaging (DWI) is a versatile modality that sensitizes observable signal to water motion, and can inform on the complexity of the tissue microstructure. Several DWI acquisition strategies are available, as are different analysis strategies, and models that attempt to capture not only simple diffusion effects, but also perfusion, compartmentalization, and anisotropy. This chapter introduces the basic concepts of DWI alongside common acquisition schemes and models, and gives an overview of specific DWI applications for animal models of renal disease.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

Renal MRI Diffusion: Experimental Protocol.

Renal diffusion-weighted imaging (DWI) can be used to obtain information on the microstructure of kidney tissue, and has the potential to provide MR-biomarkers for functional renal imaging. Here we describe in a step-by-step experimental protocol the MRI method for measuring renal diffusion coefficients in rodents using ADC or IVIM models. Both methods provide quantification of renal diffusion coefficients; however, IVIM, a more complex model, allows for the calculation of the pseudodiffusion and fraction introduced by tissue vascular and tubular components. DWI provides information of renal microstructure contributing to the understanding of the physiology and the underlying processes that precede the beginning of pathologies.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.

A randomised controlled trial to assess the feasibility of utilising virtual reality to facilitate analgesia during external cephalic version.

External cephalic version (ECV) is associated with a moderate degree of pain. Virtual reality (VR) is a technology that has shown promise in offering procedural analgesia. We undertook a clinical pilot to assess the viability of VR to reduce pain during ECV. In an open randomised controlled trial (RCT), we randomised 50 women to either VR or standard care each (25 per group). Women receiving VR were administered VR content (Skylights) via a headset. Pre- and post-procedural measures of pain, anxiety, device experience and vital signs were measured. There were no significant differences between groups (VR/no VR) in pain scores (60.68 vs 49.76; p = 0.2), ECV success rates (80% vs 76%; p = 0.7) or anxiety levels. The women receiving VR had a significantly higher anticipation of pain pre-procedurally (70.0 vs 50.0; p = 0.03). 20 (80%) of the VR women indicated that they would use VR again and 22 (88%) indicated they would recommend it to a friend having ECV. There were no significant differences between groups for side effects encountered or changes in vital signs. We have shown that using VR during ECV is feasible and appears safe. Our results inform the design of future RCTs.

Correction to: Semi-automatic segmentation from intrinsically-registered 18F-FDG-PET/MRI for treatment response assessment in a breast cancer cohort: comparison to manual DCE-MRI.

The original version of this article unfortunately contained a mistake in Fig. 6.

Semi-automatic segmentation from intrinsically-registered 18F-FDG-PET/MRI for treatment response assessment in a breast cancer cohort: comparison to manual DCE-MRI.

OBJECTIVES: To investigate the reliability of simultaneous positron emission tomography and magnetic resonance imaging (PET/MRI)-derived biomarkers using semi-automated Gaussian mixture model (GMM) segmentation on PET images, against conventional manual tumor segmentation on dynamic contrast-enhanced (DCE) images. MATERIALS AND METHODS: Twenty-four breast cancer patients underwent PET/MRI (following 18F-fluorodeoxyglucose (18F-FDG) injection) at baseline and during neoadjuvant treatment, yielding 53 data sets (24 untreated, 29 treated). Two-dimensional tumor segmentation was performed manually on DCE-MRI images (manual DCE) and using GMM with corresponding PET images (GMM-PET). Tumor area and mean apparent diffusion coefficient (ADC) derived from both segmentation methods were compared, and spatial overlap between the segmentations was assessed with Dice similarity coefficient and center-of-gravity displacement. RESULTS: No significant differences were observed between mean ADC and tumor area derived from manual DCE segmentation and GMM-PET. There were strong positive correlations for tumor area and ADC derived from manual DCE and GMM-PET for untreated and treated lesions. The mean Dice score for GMM-PET was 0.770 and 0.649 for untreated and treated lesions, respectively. DISCUSSION: Using PET/MRI, tumor area and mean ADC value estimated with a GMM-PET can replicate manual DCE tumor definition from MRI for monitoring neoadjuvant treatment response in breast cancer.

Inter-twin delivery interval, short-term perinatal outcomes and risk of caesarean for the second twin.

OBJECTIVE: To examine the association between inter-twin delivery interval and short-term perinatal outcomes of the second twin after vaginal delivery of the first twin. METHODS: Retrospective cohort study including twin pregnancies with a vaginal delivery of the first twin between January 2011 and September 2017 in a tertiary hospital in Melbourne, Australia. The main outcome measure was a composite of adverse neonatal outcome (at least one of perinatal death, admission to neonatal intensive care unit (NICU), endotracheal intubation, Apgar <7 at five minutes and cord lactate >4.0 mmol/L). Proportions of adverse outcomes for the second twin were compared between groups of intervals ≤ or >10 and ≤ or >30 min. RESULTS: The composite adverse neonatal outcome occurred in 201 (58.2%) and a caesarean section occurred in seven cases (2%) of the 345 pregnancies included. Delivery interval was associated with higher cord lactate. Low Apgar scores were more frequent with intervals >30 min (17.9% vs 6.6%, P = 0.03), as well as caesarean section for the second twin (10.7% vs 1.3%, P = 0.01). Composite adverse outcome and admission to NICU were not significantly influenced by the delivery interval. Predictors of adverse outcome were gestational age, abnormal cardiotocography and breech delivery of the second twin. CONCLUSION: The inter-twin delivery interval is associated with higher rates of low Apgar scores and higher cord lactate for the second twin. These associations do not translate into higher rates of admission to NICU and their long-term clinical implications are uncertain.

Magnetic resonance imaging T1- and T2-mapping to assess renal structure and function: a systematic review and statement paper.

This systematic review, initiated by the European Cooperation in Science and Technology Action Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease (PARENCHIMA), focuses on potential clinical applications of magnetic resonance imaging in renal non-tumour disease using magnetic resonance relaxometry (MRR), specifically, the measurement of the independent quantitative magnetic resonance relaxation times T1 and T2 at 1.5 and 3Tesla (T), respectively. Healthy subjects show a distinguishable cortico-medullary differentiation (CMD) in T1 and a slight CMD in T2. Increased cortical T1 values, that is, reduced T1 CMD, were reported in acute allograft rejection (AAR) and diminished T1 CMD in chronic allograft rejection. However, ambiguous findings were reported and AAR could not be sufficiently differentiated from acute tubular necrosis and cyclosporine nephrotoxicity. Despite this, one recent quantitative study showed in renal transplants a direct correlation between fibrosis and T1 CMD. Additionally, various renal diseases, including renal transplants, showed a moderate to strong correlation between T1 CMD and renal function. Recent T2 studies observed increased values in renal transplants compared with healthy subjects and in early-stage autosomal dominant polycystic kidney disease (ADPKD), which could improve diagnosis and progression assessment compared with total kidney volume alone in early-stage ADPKD. Renal MRR is suggested to be sensitive to renal perfusion, ischaemia/oxygenation, oedema, fibrosis, hydration and comorbidities, which reduce specificity. Due to the lack of standardization in patient preparation, acquisition protocols and adequate patient selection, no widely accepted reference values are currently available. Therefore this review encourages efforts to optimize and standardize (multi-parametric) protocols to increase specificity and to tap the full potential of renal MRR in future research.

Gefitinib and Methotrexate to Treat Ectopic Pregnancies with a Pre-Treatment Serum hCG 1000-10,000 IU/L: Phase II Open Label, Single Arm Multi-Centre Trial.

BACKGROUND: Ectopic pregnancies are a leading cause of maternal mortality. Most are treated surgically. We evaluated the efficacy and safety of combining oral gefitinib (epidermal growth factor receptor inhibitor) with methotrexate to treat larger ectopic pregnancies. METHODS: We performed a phase II, single arm, open label study across four hospitals in Edinburgh and Melbourne. We recruited women with a stable tubal ectopic pregnancy and a pre-treatment serum hCG between 1000 and 10,000 IU/L. We administered intramuscular methotrexate (50 mg/m2) once, and oral gefitinib (250 mg) for seven days. The primary outcome was the percentage successfully treated without needing surgery. To show the treatment is at least 70% effective, 28 participants were required, and 24 or more successfully treated without surgery. Secondary outcomes were safety, tolerability, and time to resolution. This study is registered (ACTRN12611001056987). FINDINGS: 30 participants with stable tubal ectopic pregnancies were recruited but two withdrew, leaving 28 participants. The median (± range) pre-treatment serum hCG was 2039 (1031-8575) IU/L and nine had pre-treatment hCGs levels >3000 IU/L. The treatment successfully resolved 86% (24/28) cases with a median (±range) time to resolution of 32 (18-67) days. The treatment caused transient rash and diarrhoea, but no serious adverse events. INTERPRETATION: Combination gefitinib and methotrexate is at least 70% effective in resolving ectopic pregnancies with a pre-treatment serum hCG 1000-10,000 IU/L. This may be a new way to treat most stable ectopic pregnancies, but needs to be validated via a randomised clinical trial.

Managing the Unmanageable: A Two-Staged Palliative Resection to Control Life-Threatening Duodenal Bleeding Due to Recurrent Paraganglioma.

BACKGROUND This report presents therapeutic decision-making and management of refractory, life-threatening duodenal bleeding in a young man with recurrent metastatic retroperitoneal paraganglioma. CASE REPORT The patient had been symptom free for 8 years after radioactive MIBG (metaiodobenzylguanidine) therapy. Failure of endoscopic or angiographic bleeding control led to urgent need to evaluate possible endocrine functional status, tumor curability, safety of incomplete resection, intra- and postoperative support needs, and anticipated recovery potential and postoperative function. Aside from these considerations, impact of tumor biology, alternative therapeutic options, current management guidelines, and ethical challenges of resource utilization for such complex palliative operative intervention were reviewed. CONCLUSIONS Based on the observed outcomes after an urgent presentation of an unusual tumor-related complication, palliation-intent therapy was justifiable even if significant treatment-related risks were expected and complex resources were required.

Evaluation of learning from Practical Obstetric Multi-Professional Training and its impact on patient outcomes in Australia using Kirkpatrick's framework: a mixed methods study.

OBJECTIVES: The aim of this study was to evaluate the implementation of the Practical Obstetric Multi-Professional Training (PROMPT) simulation using the Kirkpatrick's framework. We explored participants' acquisition of knowledge and skills, its impact on clinical outcomes and organisational change to integrate the PROMPT programme as a credentialing tool. We also aimed to assess participants' perception of usefulness of PROMPT in their clinical practice. STUDY DESIGN: Mixed methods approach with a pre-test/post-test design. SETTING: Healthcare network providing obstetric care in Victoria, Australia. PARTICIPANTS: Medical and midwifery staff attending PROMPT between 2013 and 2015 (n=508); clinical outcomes were evaluated in two cohorts: 2011-2012 (n=15 361 births) and 2014-2015 (n=12 388 births). INTERVENTION: Attendance of the PROMPT programme, a simulation programme taught in multidisciplinary teams to facilitate teaching emergency obstetric skills. MAIN OUTCOME MEASURE: Clinical outcomes compared before and after embedding PROMPT in educational practice. SECONDARY OUTCOME MEASURE: Assessment of knowledge gained by participants through a qualitative analysis and description of process of embedding PROMPT in educational practice. RESULTS: There was a change in the management of postpartum haemorrhage by early recognition and intervention. The key learning themes described by participants were being prepared with a prior understanding of procedures and equipment, communication, leadership and learning in a safe, supportive environment. Participants reported a positive learning experience and increase in confidence in managing emergency obstetric situations through the PROMPT programme, which was perceived as a realistic demonstration of the emergencies. CONCLUSION: Participants reported an improvement of both clinical and non-technical skills highlighting principles of teamwork, communication, leadership and prioritisation in an emergency situation. An improvement was observed in management of postpartum haemorrhage, but no significant change was noted in clinical outcomes over a 2-year period after PROMPT. However, the skills acquired by medical and midwifery staff justify embedding PROMPT in educational programmes.

Optimal Interval between Ultrasound Scans for the Detection of Complications in Monochorionic Twins.

INTRODUCTION: Monochorionic-diamniotic (MCDA) twin pregnancies are high risk, due to twin-to-twin transfusion syndrome (TTTS), twin anaemia polycythaemia sequence (TAPS) and intrauterine growth restriction (IUGR). There is limited evidence to guide ultrasound surveillance protocols. Using a retrospective cohort, we aimed to provide insight into the optimal interval of ultrasound surveillance. METHODS: Retrospective cohort of women with MCDA pregnancies who received antenatal care at Monash Medical Centre (January 2011-October 2014). We reviewed all ultrasounds from ≥15 weeks' gestation and collected perinatal outcomes. RESULTS: A total of 162 women with MCDA pregnancies attended our care. Six women were excluded due to late referral. Of the remaining 156, 55% were uncomplicated. TTTS, TAPS, IUGR and fetal demise in utero occurred in 9%, 1%, 31% and 2%, respectively. Median interval between the last ultrasound and TTTS diagnosis was 3.1 weeks (IQR 0.8-5.8). There was a trend towards a longer interval for cases with advanced TTTS compared to early TTTS. Interval between ultrasound scans was longer in cases with unexplained fetal demise in utero and advanced TTTS than early TTTS [3.4 weeks (IQR 2.0-6.9) vs. 0.9 weeks (IQR 0.4-3.7); p < 0.05]. DISCUSSION: Our observations support current recommendations for fortnightly ultrasound surveillance in MCDA pregnancies from 16 weeks' gestation and suggest that longer intervals may be associated with poorer outcomes.

Management of children with type 1 diabetes during illness: a national survey.

AIM: Adequate sick-day management at home can reduce the risk of progression to diabetic ketoacidosis and admission to hospital. The aim of this project was to review the management of diabetes during illness. METHOD: The Association of Children's Diabetes Clinicians (ACDC) carried out a questionnaire survey of all paediatric diabetes units. In addition, parents of children with type 1 diabetes completed an online questionnaire. RESULTS: The survey of 127 units had a 73% response rate. Sick-day management guidelines were in place in 93%. All guidelines advised giving extra insulin during illness. In 67%, the extra dose was based on a fraction of total daily dose. 22% used units per kg body weight (U/kg). 21% used locally derived formulae to calculate extra dose of insulin. 3% of units advised only blood ketone monitoring. Although all units had an out-of-hours access policy for the families, 45% received advice from the general paediatric registrar. Only in 15%, the advice was directly from a member of the paediatric diabetes team. 680 parents completed the questionnaire. 86% reported receiving training on managing sick days. The majority (52.2%) receiving an informal session at diagnosis. 40% did not know what to do in the presence of raised blood glucose and high blood ketones. CONCLUSIONS: There was a wide variation in the practice of monitoring and advice given during illness. Both surveys highlight need for national guidance as well and to improve quality of sick-day rule education programmes for parents of children with type 1 diabetes.

Muscle-damaging exercise increases heat strain during subsequent exercise heat stress.

PURPOSE: It remains unclear whether exercise-induced muscle damage (EIMD) increases heat strain during subsequent exercise heat stress, which in turn may increase the risk of exertional heat illness. We examined heat strain during exercise heat stress 30 min after EIMD to coincide with increases in circulating pyrogens (e.g., interleukin-6 [IL-6]) and 24 h after EIMD to coincide with the delayed muscle inflammatory response when a higher rate of metabolic energy expenditure (M˙) and thus decreased economy might also increase heat strain. METHODS: Thirteen non-heat-acclimated males (mean ± SD, age = 20 ± 2 yr) performed exercise heat stress tests (running for 40 min at 65% V˙O2max in 33°C, 50% humidity) 30 min (HS1) and 24 h (HS2) after treatment, involving running for 60 min at 65% V˙O2max on either -10% gradient (EIMD) or +1% gradient (CON) in a crossover design. Rectal (Tre) and skin (Tsk) temperature, local sweating rate, and M˙ were measured throughout HS tests. RESULTS: Compared with CON, EIMD evoked higher circulating IL-6 pre-HS1 (P < 0.01) and greater plasma creatine kinase and muscle soreness pre-HS2 (P < 0.01). The ΔTre was greater after EIMD than CON during HS1 (0.35°C, 95% confidence interval = 0.11°C-0.58°C, P < 0.01) and HS2 (0.17°C, 95% confidence interval = 0.07°C-0.28°C, P < 0.01). M˙ was higher on EIMD throughout HS1 and HS2 (P < 0.001). Thermoeffector responses (Tsk, sweating rate) were not altered by EIMD. Thermal sensation and RPE were higher on EIMD after 25 min during HS1 (P < 0.05). The final Tre during HS1 correlated with the pre-HS1 circulating IL-6 concentration (r = 0.67). CONCLUSIONS: Heat strain was increased during endurance exercise in the heat conducted 30 min after and, to a much lesser extent, 24 h after muscle-damaging exercise. These data indicate that EIMD is a likely risk factor for exertional heat illness particularly during exercise heat stress when behavioral thermoregulation cues are ignored.

The short Synacthen test: a questionnaire survey of current usage.

BACKGROUND: Supported by meta-analyses, the low-dose Synacthen test (LDST) has gained in popularity, with many believing it to be more sensitive than the supraphysiological standard (250 µg) short ST (SSST), particularly when assessing children prescribed high-dose inhaled corticosteroids (HDICS). However, consensus is lacking about its specific clinical application, what is considered 'low dose' and how that dose is made up. METHODS: To ascertain current use of the short Synacthen test (SST), a questionnaire was emailed to members of the British Society of Paediatric Endocrinology and Diabetes in the UK and Ireland (N=257), requesting a response from each department (N=92). A reminder was sent a month later to members of departments which had not responded. RESULTS: The authors received 39 replies, giving a response rate of 42%. All departments use the SST: 82% use an LDST, 87% use the SSST and 69% use both. The 1 µg dose was used by 44% of hospitals, with the other 56% using seven different doses based on age, weight and body surface area. There were 14 different methods of preparing the low dose test. Additionally, variations in the timings of cortisol sampling and the diagnostic cut-offs for adrenal insufficiency were found. Increased requests for SSTs in children with asthma prescribed HDICS were noted by 44% of respondents, with 67% reporting the detection of adrenal suppression in this group. CONCLUSION: Standardisation of the SST is required to address the considerable variation in the methodology and application of this test in the UK and Ireland.