Patients with knee osteoarthritis can be divided into subgroups based on tibiofemoral joint kinematics of gait - an exploratory and dynamic radiostereometric study.

OBJECTIVE: Patients with advanced knee osteoarthritis (KOA) frequently alter their gait patterns in an attempt to alleviate symptoms. Understanding the underlying pathomechanics and identifying KOA phenotypes are essential to improve treatments. We investigated kinematics in patients with KOA to identify subgroups of homogeneous knee joint kinematics. METHOD: A total of 66 patients with symptomatic KOA scheduled for total knee arthroplasty and 15 age-matched healthy volunteers with asymptomatic, non-arthritic knees were included. We used k-means clustering to divide patients into subgroups based on dynamic radiostereometry-assessed tibiofemoral joint kinematics. Clinical characteristics such as knee ligament lesions and KOA scores were graded by magnetic resonance imaging and radiographs, respectively. RESULTS: We identified four clusters that were supported by clinical characteristics. The flexion group (n = 20) consisted primarily of patients with medial KOA. The abduction group (n = 17) consisted primarily of patients with lateral KOA. The anterior draw group (n = 10) was composed of patients with medial KOA, some degree of anterior cruciate ligament lesion and the highest KOA score. The external rotation group (n = 19) primarily included patients with medial collateral and posterior cruciate ligament lesions. CONCLUSION: Based on tibiofemoral gait patterns, patients with advanced KOA can be divided into four subgroups with specific clinical characteristics and different KOA-affected compartments. The findings add to our understanding of how knee kinematics may affect the patient's development of different types of KOA. This may inspire improved and more patient-specific treatment strategies in the future.

Maternal prenatal stress and postnatal depressive symptoms: discrepancy between mother and teacher reports of toddler psychological problems.

PURPOSE: Maternal prenatal stress and postnatal depression are reported to increase the risk for early offspring psychological problems. We examined whether these two stressors predicted toddler emotional or behavioral problems based on the mother and teacher reports, respectively. METHODS: A longitudinal study within the Odense Child Cohort (OCC). Prenatal stress was assessed (gestation week 28) using Cohen's Perceived Stress Scale (PSS). Depressive symptoms were assessed (3 months after birth) using the Edinburgh Postnatal Depression Scale (EPDS). Behavioral and emotional problems were assessed by mothers using the preschool version of Child Behaviour Checklist (CBCL) and by teachers using the caregiver-teacher report form (CTR-F). RESULTS: N = 1302 mother-child dyads were included. CBCL (N = 1302) was collected at 29 months (SD 5.3) and C-TRF (N = 989) at 32.6 months (SD 6.9). N = 70 mothers (5.4%) were at high risk for postnatal depression (EPDS score > 12). Generalized additive models showed that prenatal stress (increase of + 1 on PSS-10 total score) predicted an increase in CBCL (+ 0.011) and C-TRF (+ 0.015) total scores. Postnatal depressive symptoms (increase of + 1 on EPDS total score) only predicted an increase in CBCL total score (+ 0.026). CONCLUSION: Prenatal maternal stress was a significant predictor of both mother and teacher reported toddler emotional and behavioral problems, although effect sizes were small. Postnatal depressive symptoms were associated with increased maternal (but not teacher) reporting of toddler problems. Mothers reported more toddler psychological problems than teachers, and the mother-teacher discrepancy was positively correlated to maternal postnatal depressive symptoms.

Relationship between knee joint contact forces and external knee joint moments in patients with medial knee osteoarthritis: effects of gait modifications.

OBJECTIVE: To evaluate 1) the relationship between the knee contact force (KCF) and knee adduction and flexion moments (KAM and KFM) during normal gait in people with medial knee osteoarthritis (KOA), 2) the effects on the KCF of walking with a modified gait pattern and 3) the relationship between changes in the KCF and changes in the knee moments. METHOD: We modeled the gait biomechanics of thirty-five patients with medial KOA using the AnyBody Modeling System during normal gait and two modified gait patterns. We calculated the internal KCF and evaluated the external joint moments (KAM and KFM) against it using linear regression analyses. RESULTS: First peak medial KCF was associated with first peak KAM (R2 = 0.60) and with KAM and KFM (R2 = 0.73). Walking with both modified gait patterns reduced KAM (P = 0.002) and the medial to total KCF ratio (P < 0.001) at the first peak. Changes in KAM during modified gait were moderately associated with changes in the medial KCF at the first peak (R2 = 0.54 and 0.53). CONCLUSIONS: At the first peak, KAM is a reasonable substitute for the medial contact force, but not at the second peak. First peak KFM is also a significant contributor to the medial KCF. At the first peak, walking with a modified gait reduced the ratio of the medial to total KCF but not the medial KCF itself. To determine the effects of gait modifications on cartilage loading and disease progression, longitudinal studies and individualized modeling, accounting for motion control, would be required.

Knee internal contact force in a varus malaligned phenotype in knee osteoarthritis (KOA).

PURPOSE: Multiple phenotypes characterized by different disease mechanisms have been hypothesized to explain the large variability in the knee osteoarthritis (KOA) population. The purpose of this study was: to estimate and compare the medial and lateral knee compression forces (CF) during gait of three subgroups of KOA subjects characterized by different alignment and cartilage disruption patterns. METHODS: A secondary data analysis was conducted on a sample of 39 KOA subjects and 18 controls (C). The patients were classified in the different groups according to the following criteria: Varus medial disease (VMD) (12): varus alignment and predominant medial cartilage degeneration Varus generalized disease (VGD) (17): varus alignment and cartilage degeneration that extends to the lateral compartment. Neutral alignment (NA) (10): neutral alignment. The total, medial and lateral CF corrected for body weight were estimated using an inverse dynamics model (AnyBody Modeling System, AnyBody Technology) during stance. RESULTS: The impulse of the medial compressive force (MCF) (overall effect of the CF over the stance) was significantly higher (P < 0.01) in the VMD compared to all the other groups. Peak MCF was higher in the VMD compared to all the other groups, but the difference reached significance only when compared to the VGD group (P < 0.05). The results of the regression analysis showed a significant relationship in the VMD group between alignment and impulse of the MCF (R2 = 0.62; P < 0.01). This relationship disappears in the other groups. CONCLUSIONS: These findings suggest the existence of a phenotype characterized by increased MCF.

Non-urgent Emergency Callers: Characteristics and Prognosis.

OBJECTIVE: In Denmark, calls to the Danish emergency number 1-1-2 concerning medical emergencies are received by an emergency medical communication center (EMCC). At the EMCC, health care professionals (nurses, paramedics, and physicians) decide the necessary response, depending on the level of emergency as indicated by the Danish Index for Emergency Care. The index states 37 main criteria (symptoms) and five levels of emergency, descending from A (life threatening) to E (not serious). An ambulance is not sent to emergency level-E patients (level-E patients), but they are given other kinds of help/advice. No prior studies focusing on Danish level-E patients exist, hence the sparse knowledge about them. This study aimed to characterize level-E patients in the Central Denmark Region and to investigate their progress in the health care system after the 1-1-2 call, regarding contacting 1-1-2 again, general practitioner and Emergency Department (ED) visits, hospital admission, and death. METHODS: This is a retrospective follow-up study of callers who contacted the EMCC of the Central Denmark Region and were assessed as level-E patients from August 2013 to July 2014. The study population was identified in the EMCC dispatch software, whose data were supplemented with health care data from three national registries. RESULTS: Of the 53,414 patients who called 1-1-2 over the study period, 4,962 level-E patients were included in the study. The median age was 47 years (IQR: 24.3-67.7), and 53.4% were men. The most common main criteria were extremity pain - minor wounds. Within 1 day after their 1-1-2 call, 42.1% had a subsequent contact with the health care system. Of those, 5.9% called 1-1-2 again, 24.3% contacted an ED, and 8.6% were admitted. The fatality rate was 0.1%. CONCLUSIONS: Level-E patients who contacted the EMCC of the Central Denmark Region were most frequently young adults. Almost 60% of level E-patients, who could be tracked, had no further contact with the health care system within a day after their 1-1-2 call. Of those who did, a quarter contacted an ED, indicating that level-E patients needed medical attention. The low fatality rates suggest limited undertriage, that is, level-E patients do not seem to need emergency medical service transportation. Further studies on undertriage among other things are needed.

Can public health registry data improve Emergency Medical Dispatch?

BACKGROUND: Emergency Medical Dispatchers make decisions based on limited information. We aimed to investigate if adding demographic and hospitalization history information to the dispatch process improved precision. METHODS: This 30-day follow-up study evaluated time-critical emergencies in contact with the emergency phone number 112 in Denmark during 18 months. 'Time-critical' was defined as suspected First Hour Quintet (FHQ) (cardiac arrest, chest pain, stroke, difficulty breathing, trauma). The association of age, sex, and hospitalization history with adverse outcomes was examined using logistic regression. The predictive ability was assessed via area under the curve (AUC) and Hosmer-Lemeshow tests. RESULTS: Of 59,943 patients (median age 63 years, 45% female), 44-45.5% had at least one chronic condition, 3880 (6.47%) died the day or the day after (primary outcome) calling 112. Age 30-59 was associated with increased adjusted odds ratio (OR) of death on day 1 of 3.59 [2.88-4.47]. Male sex was associated with an increased adjusted OR of death on day 1 of 1.37 [1.28-1.47]. Previous hospitalization with nutritional deficiencies (adjusted OR 2.07 [1.47-2.92]) and severe chronic liver disease (adjusted OR 2.02 [1.57-2.59]) was associated with a higher risk of death. For trauma patients, the discriminative ability of the model showed an AUC of 0.74 for death on day 1. CONCLUSION: Increasing age, male sex, and hospitalization history was associated with increased risk of death on day 1 for FHQ 112 callers. Additional efforts are warranted to clarify the role for risk prediction tools in emergency medical dispatch.

Dynamics of microbiotic patterns reveal surface water groundwater interactions in intermittent and perennial streams.

Exchange between groundwater (GW), hyporheic zone waters (HZ) and surface waters (SW) is critical for water quality, quantity, and the ecological health and functioning of all three ecosystems. Hydrological exchange is particularly important in intermittent creeks, such as in the Murray Darling Basin, Australia, where stream reaches shift from losing to gaining depending on the volume of surface flows. In this study we used hydrochemistry to identify SW-GW exchange and combined this with eDNA data to analyse the response of eukaryote and prokaryote communities to differing flow conditions within intermittent and perennial stream reaches. Our study suggested that SW and GW microbial communities were only around 30% similar. Differences in microbiota between SW, HZ and GW habitats were driven by changes in relative abundances of surface water dominant organisms (such as those capable of photosynthesis) as well as anaerobic taxa typical of GW environments (e.g., methanogens), with GW and HZ microbial communities becoming increasingly different to those in SW as flow ceased in intermittent creeks. Fine-scale hydrologic changes were identified through microbial communities in the perennial Maules Creek, indicating the importance of GW-SW exchange to biotic communities. This study highlights the importance of flow in shaping microbial communities and biogeochemical cycling within intermittent creeks and their connected alluvial aquifers. Our results suggest that microbiota may prove a useful indicator of SW-GW exchange, and in some circumstances, may be more sensitive in demonstrating fine-scale changes in SW-GW interactions than water chemistry. This knowledge furthers our understanding of GW-SW exchange and its impacts on ecological health.

Effect of lateral wedged insoles on the knee internal contact forces in medial knee osteoarthritis.

BACKGROUND: Lateral wedge insoles (LWIs) are non-surgical interventions used in medial knee osteoarthritis (KOA) aiming at restoring correct joint biomechanics. However, the mechanical efficacy of LWIs, based on modulation of the external knee adduction moment, is partially proved and high variability in response to these devices was observed. RESEARCH QUESTION: The principal aim of the study was to employ subject-specific musculoskeletal models to investigate the immediate effect of LWIs on the medial compressive force (MCF) in a population with medial KOA and varus alignment. METHODS: Fifteen adults (8 healthy controls age 56±3.4, BMI 25.2±2.2, hip-knee-ankle angle -1.3±2.3; and 7 KOA participants age 62±6.6, BMI 31.7±3.9, hip-knee-ankle angle 6.3±2) were recruited. Subject-specific LWIs were designed in CAD based on shape capture of the foot and manufactured via 3D printing. The required degree of heel post was added to the orthotic shell to create insoles with 0°, 5° and 10° of lateral wedge. Gait data were collected for each condition and a musculoskeletal model implemented in the Anybody Modeling System estimated the CFs normalised per bodyweight. The effect of the LWIs with respect to the baseline on the peak and the impulse of the MCF were tested with a Wilcoxon non-parametric test for paired samples. RESULTS: For the KOA group, LWIs did not reduce significantly the impulse and the peak of the MCF. No dose-response trend according to the degree of wedging was observed. A high inter-subject variability was found: the impulse of the MCF varied between -12%, +10%, the peak between -5%, +7%. Moreover, LWIs had no consistent effect on shifting the load from the medial to the lateral compartment. SIGNIFICANCE: Subject-specific response to LWIs in a cohort of medial KOA patients was observed. Further studies are necessary to maximise the mechanical effect of LWIs on restoring normal knee joint mechanics.

Evaluation of predicted patellofemoral joint kinematics with a moving-axis joint model.

The main objectives of this study were to expand the moving-axis joint model concept to the patellofemoral joint and evaluate the patellar motion against experimental patellofemoral kinematics. The experimental data was obtained through 2D-to-3D bone reconstruction of EOS images and segmented MRI data utilizing an iterative closest point optimization technique. Six knee model variations were developed using the AnyBody Modeling System and subject-specific bone geometries. These models consisted of various combinations of tibiofemoral (hinge, moving-axis, and interpolated) and patellofemoral (hinge and moving-axis) joint types. The newly introduced interpolated tibiofemoral joint is calibrated from the five EOS quasi-static lunge positions. The patellofemoral axis of the hinge model was defined by performing surface fits to the patellofemoral contact area; and the moving-axis model was defined based upon the position of the patellofemoral joint at 0° and 90° tibiofemoral-flexion. In between these angles, the patellofemoral axis moved linearly as a function of tibiofemoral-flexion, while outside these angles, the axis remained fixed. When using a moving-axis tibiofemoral joint, a hinge patellofemoral joint offers (-5.12 ± 1.23 mm, 5.81 ± 0.97 mm, 14.98 ± 2.30°, -4.35 ± 1.95°) mean differences (compared to EOS) while a moving-axis patellofemoral model provides (-2.69 ± 1.04 mm, 1.13 ± 0.80 mm, 12.63 ± 2.03°, 1.74 ± 1.46°) in terms of lateral-shift, superior translation, patellofemoral-flexion, and patellar-rotation, respectively. Furthermore, the model predictive capabilities increased as a direct result of adding more calibrated positions to the tibiofemoral model (hinge-1, moving-axis-2, and interpolated-5). Overall, a novel subject-specific moving-axis patellofemoral model has been established; that produces realistic patellar motion and is computationally fast enough for clinical applications.

Gait alteration strategies for knee osteoarthritis: a comparison of joint loading via generic and patient-specific musculoskeletal model scaling techniques.

Gait modifications and laterally wedged insoles are non-invasive approaches used to treat medial compartment knee osteoarthritis. However, the outcome of these alterations is still a controversial topic. This study investigates how gait alteration techniques may have a unique effect on individual patients; and furthermore, the way we scale our musculoskeletal models to estimate the medial joint contact force may influence knee loading conditions. Five patients with clinical evidence of medial knee osteoarthritis were asked to walk at a normal walking speed over force plates and simultaneously 3D motion was captured during seven conditions (0°-, 5°-, 10°-insoles, shod, toe-in, toe-out, and wide stance). We developed patient-specific musculoskeletal models, using segmentations from magnetic resonance imaging to morph a generic model to patient-specific bone geometries and applied this morphing to estimate muscle insertion sites. Additionally, models were created of these patients using a simple linear scaling method. When examining the patients' medial compartment contact force (peak and impulse) during stance phase, a 'one-size-fits-all' gait alteration aimed to reduce medial knee loading did not exist. Moreover, the different scaling methods lead to differences in medial contact forces; highlighting the importance of further investigation of musculoskeletal modeling methods prior to use in the clinical setting.

A novel non-invasive method for measuring knee joint laxity in four dof: In vitro proof-of-concept and validation.

Knee joint laxity or instability is a common problem that may have detrimental consequences for patients. Unfortunately, assessment of knee joint laxity is limited by current methodologies resulting in suboptimal diagnostics and treatment. This paper presents a novel method for accurately measuring non-invasive knee joint laxity in four degrees-of-freedom (DOF). An arthrometer, combining a parallel manipulator and a six-axis force/moment sensor, was developed to be used in combination with a low-dose biplanar x-ray system and 3D image data to reconstruct tibiofemoral position and orientation of laxity measurements. As proof-of-concept, four cadaveric knees were tested in the device. Each cadaveric knee was mounted in the device at approximately 30° of flexion and twelve monoplanar anteroposterior, mediolateral and internal/external load cases were applied. Additionally, four biplanar load cases were applied, consisting of different combinations of anteroposterior and internal/external loads. The arthrometer was limited to four DOF to address the specific measurements. For validation purposes, the pose reconstructions of tibia and femur were compared with pose reconstructions of bone pin marker frames mounted on each bone. The measurements from the arthrometer in terms of translation and rotations displayed comparable values to what have previously been presented in the literature. Furthermore, the measurements revealed coupled motions in multiple planes, demonstrating the importance of multi DOF laxity measurements. The validation displayed an average mean difference for translations of 0.08 mm and an average limit of agreement between -1.64 mm and 1.80 mm. The average mean difference for rotations was 0.10° and the limit of agreement was between -0.85° and 1.05°. The presented method eliminates several limitations present in current methods and may prove a valuable tool for assessing knee joint laxity.

Development and validation of a subject-specific moving-axis tibiofemoral joint model using MRI and EOS imaging during a quasi-static lunge.

The aims of this study were to introduce and validate a novel computationally-efficient subject-specific tibiofemoral joint model. Subjects performed a quasi-static lunge while micro-dose radiation bi-planar X-rays (EOS Imaging, Paris, France) were captured at roughly 0°, 20°, 45°, 60°, and 90° of tibiofemoral flexion. Joint translations and rotations were extracted from this experimental data through 2D-to-3D bone reconstructions, using an iterative closest point optimization technique, and employed during model calibration and validation. Subject-specific moving-axis and hinge models for comparisons were constructed in the AnyBody Modeling System (AMS) from Magnetic Resonance Imaging (MRI)-extracted anatomical surfaces and compared against the experimental data. The tibiofemoral axis of the hinge model was defined between the epicondyles while the moving-axis model was defined based on two tibiofemoral flexion angles (0° and 90°) and the articulation modeled such that the tibiofemoral joint axis moved linearly between these two positions as a function of the tibiofemoral flexion. Outside this range, the joint axis was assumed to remain stationary. Overall, the secondary joint kinematics (ML: medial-lateral, AP: anterior-posterior, SI: superior-inferior, IE: internal-external, AA: adduction-abduction) were better approximated by the moving-axis model with mean differences and standard errors of (ML: -1.98 ±â€¯0.37 mm, AP: 6.50 ±â€¯0.82 mm, SI: 0.05 ±â€¯0.20 mm, IE: 0.59 ±â€¯0.36°, AA: 1.90 ±â€¯0.79°) and higher coefficients of determination (R2) for each clinical measure. While the hinge model achieved mean differences and standard errors of (ML: -0.84 ±â€¯0.45 mm, AP: 10.11 ±â€¯0.88 mm, SI: 0.66 ±â€¯0.62 mm, IE: -3.17 ±â€¯0.86°, AA: 11.60 ±â€¯1.51°).

Workflow assessing the effect of gait alterations on stresses in the medial tibial cartilage - combined musculoskeletal modelling and finite element analysis.

Knee osteoarthritis (KOA) is most common in the medial tibial compartment. We present a novel method to study the effect of gait modifications and lateral wedge insoles (LWIs) on the stresses in the medial tibial cartilage by combining musculoskeletal (MS) modelling with finite element (FE) analysis. Subject's gait was recorded in a gait laboratory, walking normally, with 5° and 10° LWIs, toes inward ('Toe in'), and toes outward ('Toe out wide'). A full lower extremity MRI and a detailed knee MRI were taken. Bones and most soft tissues were segmented from images, and the generic bone architecture of the MS model was morphed into the segmented bones. The output forces from the MS model were then used as an input in the FE model of the subject's knee. During stance, LWIs failed to reduce medial peak pressures apart from Insole 10° during the second peak. Toe in reduced peak pressures by -11% during the first peak but increased them by 12% during the second. Toe out wide reduced peak pressures by -15% during the first and increased them by 7% during the second. The results show that the work flow can assess the effect of interventions on an individual level. In the future, this method can be applied to patients with KOA.

Testosterone therapy preserves muscle strength and power in aging men with type 2 diabetes-a randomized controlled trial.

The purpose of the study was to evaluate whether testosterone replacement therapy improves muscle mechanical and physical function in addition to increasing lean leg mass and total lean body mass in aging men with type 2 diabetes and lowered bio-available testosterone (BioT) levels. Thirty-nine men aged 50-70 years with type 2 diabetes and BioT levels <7.3 nmol/L were included from an academic tertiary-care medical center. Patients were randomized to testosterone gel (testosterone replacement therapy, n = 20) or placebo (n = 19) for 24 weeks, applying a double-blinded design. Muscle mechanical function was assessed by Nottingham Leg Rig (leg extension power) and isokinetic dynamometry (knee extensor maximal isometric contraction, rate of force development (RFD100), maximal dynamic contraction (Dyn180)). Physical function was assessed by gait speed. Body composition was assessed by whole body dual-energy X-ray absorptiometry (total lean body mass, lean leg mass, total fat mass, leg fat mass). Levels of total testosterone (TotalT), BioT, free testosterone (FreeT), and sex hormone-binding globulin were measured from fasting blood samples. Coefficients (b) represent the placebo-controlled mean effect of intervention. Maximal isometric contraction (b = 18.4 Nm, p = 0.039), RFD100 (b = 195.0 Nm/s, p = 0.017) and Dyn180 (b = 10.2 Nm, p = 0.019) increased during testosterone replacement therapy compared with placebo. No changes were observed in leg power or gait speed. Total lean body mass (b = 1.9 kg, p = 0.001) and lean leg mass (b = 0.5 kg, p < 0.001) increased, while total fat mass (b = -1.3 kg, p = 0.009) and leg fat mass (b = -0.7 kg, p = 0.025) decreased during testosterone replacement therapy compared with placebo. Total T (b = 14.5 nmol/L, p = 0.056), BioT (b = 7.6 nmol/L, p = 0.046), and FreeT (b = 0.32 nmol/L, p = 0.046) increased during testosterone replacement therapy compared with placebo, while sex hormone-binding globulin (n = -2 nmol/L, p = 0.030) decreased. Knee extensor muscle mechanical function was preserved, and body composition improved substantially during testosterone replacement therapy for 24 weeks compared with placebo, whereas physical function (gait speed) was unchanged in aging men with type 2 diabetes and lowered BioT levels.

Validation of static and dynamic radiostereometric analysis of the knee joint using bone models from CT data.

OBJECTIVES: Static radiostereometric analysis (RSA) using implanted markers is considered the most accurate system for the evaluation of prosthesis migration. By using CT bone models instead of markers, combined with a dynamic RSA system, a non-invasive measurement of joint movement is enabled. This method is more accurate than current 3D skin marker-based tracking systems. The purpose of this study was to evaluate the accuracy of the CT model method for measuring knee joint kinematics in static and dynamic RSA using the marker method as the benchmark. METHODS: Bone models were created from CT scans, and tantalum beads were implanted into the tibia and femur of eight human cadaver knees. Each specimen was secured in a fixture, static and dynamic stereoradiographs were recorded, and the bone models and marker models were fitted to the stereoradiographs. RESULTS: Results showed a mean difference between the two methods in all six degrees of freedom for static RSA to be within -0.10 mm/° and 0.08 mm/° with a 95% limit of agreement (LoA) ranging from ± 0.49 to 1.26. Dynamic RSA had a slightly larger range in mean difference of -0.23 mm/° to 0.16 mm/° with LoA ranging from ± 0.75 to 1.50. CONCLUSIONS: In a laboratory-controlled setting, the CT model method combined with dynamic RSA may be an alternative to previous marker-based methods for kinematic analyses.Cite this article: K. Stentz-Olesen, E. T. Nielsen, S. De Raedt, P. B. Jørgensen, O. G. Sørensen, B. L. Kaptein, M. S. Andersen, M. Stilling. Validation of static and dynamic radiostereometric analysis of the knee joint using bone models from CT data. Bone Joint Res 2017;6:376-384. DOI: 10.1302/2046-3758.66.BJR-2016-0113.R3.

Risk factors for colic in horses after general anaesthesia for MRI or nonabdominal surgery: absence of evidence of effect from perianaesthetic morphine.

REASON FOR PERFORMING STUDY: Post anaesthetic colic is a recognised risk of general anaesthesia (GA), but causes are poorly understood. OBJECTIVES: To identify risk factors for development of colic following GA for magnetic resonance imaging (MRI) or nonabdominal surgery and to test whether the use of perianaesthetic morphine was associated with an increased risk of post anaesthetic colic. METHODS: A total of 553 anaesthetic and clinical records of 500 horses anaesthetised at the Animal Health Trust were analysed, 342 (62%) involved MRI and 211 (38%) nonabdominal, predominantly orthopaedic surgery. Multivariable logistic regression analysis was used to examine the association between post anaesthetic colic and explanatory variables, including use of perianaesthetic morphine. RESULTS: Twenty horses (3.6%) developed colic within 7 days of GA. A significantly larger (P = 0.001) proportion of the surgical cases developed post anaesthetic colic (7.1%) compared with MRI cases (1.5%). Having controlled for the effect of MRI/surgeon, there was evidence for a significantly increased risk of colic associated with maintenance of anaesthesia with isoflurane and administration of benzyl penicillin and/or ceftiofur. A reduction in risk of colic was associated with premedication with romifidine, longer duration of anaesthesia and sedation within 2 days of GA. Perianaesthetic morphine administration was not associated with increased risk. CONCLUSIONS: This study identified apparently novel risk factors for colic in horses following GA. Use of morphine was not found, after controlling for other MRI and surgery related risk factors, to be associated with an increased risk. The low prevalence of colic after GA and resulting low study power mean that further larger, multicentre collaborative studies are warranted to corroborate findings in this study. POTENTIAL RELEVANCE: Better knowledge of risk factors should lead to achievable measures to reduce frequency of occurrence.

A study of police operated dispatch to acute coronary syndrome cases arising from 112 emergency calls in Aarhus county, Denmark.

BACKGROUND: The accuracy of the Danish police operated "112" emergency call system was studied. Dispatch of the anaesthesiologist staffed mobile emergency care unit (MECU) to acute coronary syndrome (ACS) cases was used as an indicator of accuracy of dispatch to life threatening emergencies. METHODS: This was an observational cohort study of patients given a 112 system report of heart attack and patients with a provisional diagnosis of ACS made on scene by the MECU. Sensitivity, specificity, and positive predictive value with 95% confidence intervals (CI) were calculated. RESULTS: There were 341 reports of "heart attack" and 205 patients with ACS. Sensitivity was 75% (95% CI 68% to 80%) specificity 90% (89% to 92%) and positive predictive value 45% (40% to 50%). CONCLUSION: The accuracy of 112 dispatch of the MECU was found to be moderate. We suggest more training of dispatch staff and medical supervision.

The association between angiogenic markers and fetal sex: Implications for preeclampsia research.

OBJECTIVE: Current research suggests sexual dimorphism between the male and female fetoplacental units, but with unknown relevance for preeclampsia. We investigated the association between fetal sex and concentrations of the angiogenic markers soluble Fms-like kinase 1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio in first and second-third trimester in women with/without preeclampsia, and the impact of fetal sex on the prognostic value of angiogenic markers for preeclampsia. STUDY DESIGN: Observational study in a prospective, population-based cohort of 2110 singleton pregnancies with 150 preeclampsia cases. RESULTS: Higher sFlt-1 concentrations were observed for women carrying female fetuses in first trimester (all, 1107.65 vs. 992.27pg/ml; preeclampsia cases, 1118.79 vs. 934.49pg/ml, p<0.05) and in second-third trimester (all, 1130.03 vs. 1043.15pg/ml; preeclampsia, 1480.30 vs. 1152.86pg/ml, p<0.05), with similar findings for the sFlt-1/PlGF ratio concentrations in first (29.67 vs. 27.39 p<0.05) and second-third trimester (3.56 vs. 3.22, p<0.05). In first trimester, log transformed concentrations of PlGF, sFlt-1 and sFlt-1/PlGF (all participants) and sFlt-1 (preeclampsia cases) associated with fetal sex in adjusted analyses (p<0.05). In second-third trimester, only log(sFlt-1) associated with fetal sex (all, p=0.028; preeclampsia, p=0.067) In receiver operating curve analysis, prediction of early-onset preeclampsia by sFlt-1/PlGF tended to be superior in pregnancies with female vs. male fetuses (p=0.06). CONCLUSION: Sexual dimorphism was observed for concentrations of angiogenic markers. Female fetal sex was associated to higher sFlt-1 and sFlt-1/PlGF ratio concentrations in both healthy pregnancies and women developing preeclampsia. Fetal sex should be considered in research and clinical use of angiogenic markers.

Risk factors for faecal sand excretion in Icelandic horses.

REASONS FOR PERFORMING STUDY: Sandy soil is often mentioned as a risk factor in the development of sand-related gastrointestinal disease (SGID) in the horse. There are other variables, but few studies confirm any of these. OBJECTIVE: To investigate soil type, pasture quality, feeding practice in the paddock, age, sex and body condition score as risk factors for sand intake in the horse. METHODS: Faeces were collected from 211 Icelandic horses on 19 different studs in Denmark together with soil samples and other potential risk factors. Sand content in faeces determined by a sand sedimentation test was interpreted as evidence of sand intake. Soil types were identified by soil analysis and significance of the data was tested using logistic analysis. RESULTS: Of horses included in the study, 56.4% showed sand in the faeces and 5.7% had more than 5 mm sand as quantified by the rectal sleeve sedimentation test. Soil type had no significant effect when tested as main effect, but there was interaction between soil type and pasture quality. Significant interactions were also found between paddock feeding practice and pasture quality. CONCLUSION: To evaluate the risk of sand intake it is important to consider 3 variables: soil type, pasture quality and feeding practice. Pasture quality was identified as a risk factor of both short and long grass in combination with sandy soil, while clay soil had the lowest risk in these combinations. Feeding practice in the paddock revealed feeding directly on the ground to be a risk factor when there was short (1-5 cm) or no grass. Also, no feeding outdoors increased the risk on pastures with short grass, while this had no effect in paddocks with no grass. More than 50% of all horses investigated in this study had sand in the faeces. POTENTIAL RELEVANCE: The identification of risk factors is an important step towards prevention of SGID. Further research is necessary to determine why some horses exhibit more than 5 mm sand in the sedimentation test and whether this is correlated with geophagic behaviour.

Dissolved Organic Carbon Mobilisation in a Groundwater System Stressed by Pumping.

The concentration and flux of organic carbon in aquifers is influenced by recharge and abstraction, and surface and subsurface processing. In this study groundwater was abstracted from a shallow fractured rock aquifer and dissolved organic carbon (DOC) was measured in observation bores at different distances from the abstraction bore. Groundwater abstraction at rates exceeding the aquifers yield resulted in increased DOC concentration up to 3,500 percent of initial concentrations. Potential sources of this increased DOC were determined using optical fluorescence and absorbance analysis. Groundwater fluorescent dissolved organic material (FDOM) were found to be a combination of terrestrial-derived humic material and microbial or protein sourced material. Relative molecular weight of FDOM within four metres of the abstraction well increased during the experiment, while the relative molecular weight of FDOM between four and ten metres from the abstraction well decreased. When the aquifer is not being pumped, DOC mobilisation in the aquifer is low. We hypothesise that the physical shear stress on aquifer materials caused by intense abstraction significantly increases the temporary release of DOC from sloughing of biofilms and release of otherwise bound colloidal and sedimentary organic carbon (SOC).