Explicit teaching in the operating room:Adding the why to the what

CONTEXT: Residents need their supervisors in the operating room to inform them on how to use their expertise in present and future occasions. A few studies hint at such explicit teaching behaviour, however without explaining its underlying mechanisms. Understanding and improving explicit teaching becomes more salient nowadays, as access of residents to relevant procedures is decreasing, while end-terms of training programs remain unchanged: high quality patient care. OBJECTIVES: A structured analysis of 1. The practices supervisors use for explicit teaching and 2. How supervisors introduce explicit teaching in real time during surgical procedures. METHODS: An observational qualitative collection study in which all actions of nine supervisor-resident dyads during a total hip replacement procedure were videotaped. Interactions in which supervisors explicitly or implicitly inform residents how to use their expertise now and in future occasions were included for further analysis, using the iterative inductive process of conversation analysis. RESULTS: 1. Supervisors used a basic template of if/then rules for explicit teaching, which they regularly customized by adding metaphors, motivations, and information about preference, prevalence and consequence. 2. If/then rules are introduced by supervisors to solve a (potential) problem in outcome for the present patient in reaction to local circumstances, e.g. what residents said, did or were about to do. CONCLUSIONS: If/then rules add the why to the what. Supervisors upgrade residents' insights in surgical procedures (professional vision) and teach the degree of individual freedom and variation of their expert standards for future occasions. These insights can be beneficial in improving supervisors' teaching skills

Rating of pre-injury symptoms over time in patients with mild traumatic brain injury:The good-old-days-bias revisited

Objective Post-concussion syndrome (PCS) occurs following mild traumatic brain injury (mTBI). Patients with mTBI are often assessed using self-report instruments that rely on perception of current symptoms compared to how they felt and functioned pre-injury. The objective was to examine reliability of patients’ post-injury reporting of their pre-injury symptoms. Methods We included two control groups (trauma patients without brain injury history and healthy controls) who were recruited at an outpatient surgical clinic and among the working and social environment of the researchers, respectively. The Head Injury Symptom Checklist (HISC) was used to assess pre-injury and current symptoms at four time points post injury. We included 836 patients with mTBIs, 191 trauma patients without brain injury history, and 100 healthy controls. Results Patients with mTBI reported significantly more pre-injury symptoms than both control groups (p < .001). Forty-five percent of patients with mTBI were inconsistent in their pre-injury ratings across four assessments. Patients with post-injury PCS reported much greater pre-injury symptoms and were more often inconsistent. Conclusion Accurately assessing PCS by comparing pre with post-injury complaints is difficult, and may have implications for diagnosis when using self-report instruments. Therefore, post-injury PCS diagnosis should be interpreted with caution and PCS should ideally be examined using clinical examination

A scenario of planet erosion by coronal radiation

Context: According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long term effects of erosion have yet been made. Aims: To analyze the current distribution of planetary mass with X-ray irradiation of the atmospheres in order to make an observational assessment of the effects of erosion by coronal radiation. Methods: We study a large sample of planet-hosting stars with XMM-Newton, Chandra and ROSAT; make a careful identification of X-ray counterparts; and fit their spectra to make accurately measurements of the stellar X-ray flux. Results: The distribution of the planetary masses with X-ray flux suggests that erosion has taken place: most surviving massive planets, (M_p sin i >1.5 M_J), have been exposed to lower accumulated irradiation. Heavy erosion during the initial stages of stellar evolution is followed by a phase of much weaker erosion. A line dividing these two phases could be present, showing a strong dependence on planet mass. Although a larger sample will be required to establish a well-defined erosion line, the distribution found is very suggestive. Conclusions: The distribution of planetary mass with X-ray flux is consistent with a scenario in which planet atmospheres have suffered the effects of erosion by coronal X-ray and EUV emission. The erosion line is an observational constraint to models of atmospheric erosion.Comment: A&A 511, L8 (2010). 4 pages, 3 figures, 1 online table (included). Language edited; corrected a wrong unit conversion (g/s -> M_J/Gyr); corrected values in column 12 of Table 1 (slightly underestimated in first version), and Figure 2 updated accordingl

Population pharmacokinetics of the von Willebrand factor-factor VIII interaction in patients with von Willebrand disease

Recent studies have reported that patients with von Willebrand disease treated perioperatively with a von Willebrand factor (VWF)/factor VIII (FVIII) concentrate with a ratio of 2.4:1 (Humate P/Haemate P) often present with VWF and/or FVIII levels outside of prespecified target levels necessary to prevent bleeding. Pharmacokinetic (PK)-guided dosing may resolve this problem. As clinical guidelines increasingly recommend aiming for certain target levels of both VWF and FVIII, application of an integrated population PK model describing both VWF activity (VWF:Act) and FVIII levels may improve dosing and quality of care. In total, 695 VWF:Act and 894 FVIII level measurements from 118 patients (174 surgeries) who were treated perioperatively with the VWF/FVIII concentrate were used to develop this population PK model using nonlinear mixed-effects modeling. VWF:Act and FVIII levels were analyzed simultaneously using a turnover model. The protective effect of VWF:Act on FVIII clearance was described with an inhibitory maximum effect function. An average perioperative VWF:Act level of 1.23 IU/mL decreased FVIII clearance from 460 mL/h to 264 mL/h, and increased FVIII half-life from 6.6 to 11.4 hours. Clearly, in the presence of VWF, FVIII clearance decreased with a concomitant increase of FVIII half-life, clarifying the higher FVIII levels observed after repetitive dosing with this concentrate. VWF:Act and FVIII levels during perioperative treatment were described adequately by this newly developed integrated population PK model. Clinical application of this model may facilitate more accurate targeting of VWF:Act and FVIII levels during perioperative treatment with this specific VWF/FVIII concentrate (Humate P/Haemate P).Thrombosis and Hemostasi

Methods of prediction and prevention of pre-eclampsia: Systematic reviews of accuracy and effectiveness literature with economic modelling

© Queen's Printer and Controller of HMSO 2008. This monograph may be freely reproduced for the purposes of private research and study and may be included in professional journals provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising.Objectives: To investigate the accuracy of predictive tests for pre-eclampsia and the effectiveness of preventative interventions for pre-eclampsia. Also to assess the cost-effectiveness of strategies (test-intervention combinations) to predict and prevent pre-eclampsia. Data sources: Major electronic databases were searched to January 2005 at least. Review methods: Systematic reviews were carried out for test accuracy and effectiveness. Quality assessment was carried out using standard tools. For test accuracy, meta-analyses used a bivariate approach. Effectiveness reviews were conducted under the auspices of the Cochrane Pregnancy and Childbirth Group and used standard Cochrane review methods. The economic evaluation was from an NHS perspective and used a decision tree model. Results: For the 27 tests reviewed, the quality of included studies was generally poor. Some tests appeared to have high specificity, but at the expense of compromised sensitivity. Tests that reached specificities above 90% were body mass index > 34, α-foetoprotein and uterine artery Doppler (bilateral notching). The only Doppler test with a sensitivity of over 60% was resistance index and combinations of indices. A few tests not commonly found in routine practice, such as kallikreinuria and SDS-PAGE proteinuria, seemed to offer the promise of high sensitivity, without compromising specificity, but these would require further investigation. For the 16 effectiveness reviews, the quality of included studies was variable. The largest review was of antiplatelet agents, primarily low-dose aspirin, and included 51 trials (36,500 women). This was the only review where the intervention was shown to prevent both preeclampsia and its consequences for the baby. Calcium supplementation also reduced the risk of preeclampsia, but with some uncertainty about the impact on outcomes for the baby. The only other intervention associated with a reduction in RR of pre-eclampsia was rest at home, with or without a nutritional supplement, for women with normal blood pressure. However, this review included just two small trials and its results should be interpreted with caution. The cost of most of the tests was modest, ranging from £5 for blood tests such as serum uric acid to approximately £20 for Doppler tests. Similarly, the cost of most interventions was also modest. In contrast, the best estimate of additional average cost associated with an average case of pre-eclampsia was high at approximately £9000. The results of the modelling revealed that prior testing with the test accuracy sensitivities and specificities identified appeared to offer little as a way of improving cost-effectiveness. Based on the evidence reviewed, none of the tests appeared sufficiently accurate to be clinically useful and the results of the model favoured no-test/treat-all strategies. Rest at home without any initial testing appeared to be the most cost-effective 'test-treatment' combination. Calcium supplementation to all women, without any initial testing, appeared to be the second most cost-effective. The economic model provided little support that any form of Doppler test has sufficiently high sensitivity and specificity to be cost-effective for the early identification of pre-eclampsia. It also suggested that the pattern of cost-effectiveness was no different in high-risk mothers than the low-risk mothers considered in the base case. Conclusions: The tests evaluated are not sufficiently accurate, in our opinion, to suggest their routine use in clinical practice. Calcium and antiplatelet agents, primarily low-dose aspirin, were the interventions shown to prevent pre-eclampsia. The most cost-effective approach to reducing pre-eclampsia is likely to be the provision of an effective, affordable and safe intervention applied to all mothers without prior testing to assess levels of risk. It is probably premature to suggest the implementation of a treat-all intervention strategy at present, however the feasibility and acceptability of this to women could be explored. Rigorous evaluation is needed of tests with modest cost whose initial assessments suggest that they may have high levels of both sensitivity and specificity. Similarly, there is a need for high-quality, adequately powered randomised controlled trials to investigate whether interventions such as advice to rest are indeed effective in reducing pre-eclampsia. In future, an economic model should be developed that considers not just pre-eclampsia, but other related outcomes, particularly those relevant to the infant such as perinatal death, preterm birth and small for gestational age. Such a modelling project should make provision for primary data collection on the safety of interventions and their associated costs.National Institute for Health Researc

Treatment of patients with rare bleeding disorders in the Netherlands:Real-life data from the RBiN study

Background Patients with rare inherited bleeding disorders (RBDs) exhibit hemorrhagic symptoms, varying in type and severity, often requiring only on-demand treatment. Prolonged bleeding after invasive procedures is common. Adequate peri-procedural therapy may reduce this bleeding risk. Objective To describe general treatment plans of RBD patients and evaluate the use of peri-procedural hemostatic therapy. Methods In the Rare Bleeding Disorders in the Netherlands (RBiN) study, RBD patients from all six Dutch Hemophilia Treatment Centers were included. General treatment plans were extracted from patient files. Patients with a dental or surgical procedure in their history were interviewed about use of peri-procedural treatment and bleeding complications. Results Two-hundred sixty-three patients with a rare coagulation factor deficiency or fibrinolytic disorder were included. Eighty-four percent had a documented general treatment plan. General treatment plans of patients with the same RBD were heterogeneous, particularly in factor XI deficiency. Overall, 308 dental and 408 surgical procedures were reported. Bleeding occurred in 50% of dental and 53% of surgical procedures performed without hemostatic treatment and in 28% of dental and 19% of surgical procedures performed with hemostatic treatment. Not only patients with severe RBDs, but also patients with mild deficiencies, experienced increased bleeding without proper hemostatic treatment. Conclusion Large heterogeneity in general treatment plans of RBD patients was found. Bleeding after invasive procedures was reported frequently, both before and after RBD diagnosis, irrespective of factor activity levels and particularly when peri-procedural treatment was omitted. Improved guidelines should include uniform recommendations for most appropriate hemostatic products per RBD and emphasize the relevance of individual bleeding history

Effectiveness of a guided self-help exercise program tailored to patients treated with total laryngectomy:Results of a multi-center randomized controlled trial

Objective: To investigate the effectiveness of a guided self-help exercise program on swallowing, speech, and shoulder problems in patients treated with total laryngectomy (TL). Materials and methods: This randomized controlled trial included patients treated with TL in the last 5 years. Patients were randomized into the intervention group (self-help exercise program with flexibility, range-of-motion and lymphedema exercises and self-care education program) or control group (self-care education program). Both groups completed measurements before and 3 and 6-months after randomization. The primary outcome was swallowing problems (SWAL-QOL). Secondary outcomes were speech problems (SHI), shoulder problems (SDQ), self-management (patient activation: PAM) and health-related quality of life (HRQOL: EORTC QLQ-C30/H&N35). Adherence was defined as moderate-high in case a patient exercised >1 per day. Linear mixed model analyses were conducted to investigate the effectiveness of the intervention and to investigate whether neck dissection, treatment indication (primary/salvage TL), time since treatment, severity of problems, and preferred format (online/booklet) moderated the effectiveness. Results: Moderate-high adherence to the exercise program was 59%. The intervention group (n = 46) reported less swallowing and communication problems over time compared to the control group (n = 46) (p-value = 0.013 and 0.004). No difference was found on speech, shoulder problems, patient activation and HRQOL. Time since treatment moderated the effectiveness on speech problems (p-value = 0.025): patients within 6 months after surgery benefitted most from the intervention. Being treated with a neck dissection, treatment indication, severity of problems and format did not moderate the effectiveness. Conclusion: The guided self-help exercise program improves swallowing and communication. Trial registration. NTR5255

Adjusting for confounding by indication in observational studies: a case study in traumatic brain injury.

INTRODUCTION: Observational studies of interventions are at risk for confounding by indication. The objective of the current study was to define the circumstances for the validity of methods to adjust for confounding by indication in observational studies. PATIENTS AND METHODS: We performed post hoc analyses of data prospectively collected from three European and North American traumatic brain injury studies including 1,725 patients. The effects of three interventions (intracranial pressure [ICP] monitoring, intracranial operation and primary referral) were estimated in a proportional odds regression model with the Glasgow Outcome Scale as ordinal outcome variable. Three analytical methods were compared: classical covariate adjustment, propensity score matching and instrumental variable (IV) analysis in which the percentage exposed to an intervention in each hospital was added as an independent variable, together with a random intercept for each hospital. In addition, a simulation study was performed in which the effect of a hypothetical beneficial intervention (OR 1.65) was simulated for scenarios with and without unmeasured confounders. RESULTS: For all three interventions, covariate adjustment and propensity score matching resulted in negative estimates of the treatment effect (OR ranging from 0.80 to 0.92), whereas the IV approach indicated that both ICP monitoring and intracranial operation might be beneficial (OR per 10% change 1.17, 95% CI 1.01-1.42 and 1.42, 95% CI 0.95-1.97). In our simulation study, we found that covariate adjustment and propensity score matching resulted in an invalid estimate of the treatment effect in case of unmeasured confounders (OR ranging from 0.90 to 1.03). The IV approach provided an estimate in the similar direction as the simulated effect (OR per 10% change 1.04-1.05) but was statistically inefficient. CONCLUSION: The effect estimation of interventions in observational studies strongly depends on the analytical method used. When unobserved confounding and practice variation are expected in observational multicenter studies, IV analysis should be considered