Estimating Inert Gas Bubbling from Simple SCUBA Diving Parameters.

Inert gas bubbles frequently occur in SCUBA divers' vascular systems, eventually leading to decompression accidents. Only in professional settings, dive profiles can be adjusted on individual basis depending on bubble grades detected through ultrasonography. A total of 342 open-circuit air dives following sports diving profiles were assessed using echocardiography. Subsequently, (Eftedal-Brubakk) bubble grades were correlated with dive and individual parameters. Post-dive cardiac bubbles were observed in 47% of all dives and bubble grades were significantly correlated with depth (r=0.46), air consumption (r=0.41), age (r=0.25), dive time (r=0.23), decompression diving (r=0.19), surface time (r=- 0.12). Eftedal-Brubakk categorical bubble grades for sports diving with compressed air can be approximated by bubble grade = (age*50-1 - surface time*150-1+maximum depth*45-1+air consumption*4500-1)2 (units in years, hours, meter, and bar*liter; R2=0.31). Thus, simple dive and individual parameters allow reasonable estimation of especially relevant medium to higher bubble grades for information on relevant decompression stress after ascent. Echo bubble grade 0 is overestimated by the formula derived. However, echo might fail to detect minor bubbling only. The categorical prediction of individual decompression stress with simple bio and dive data should be evaluated further to be developed towards dive computer included automatic ex-post information for decision-making on individual safety measures.

Optimal experimental design for joint reflection-transmission ultrasound breast imaging: From ray- to wave-based methods.

Ultrasound computed tomography (USCT) is an emerging modality to image the acoustic properties of the breast tissue for cancer diagnosis. With the need of improving the diagnostic accuracy of USCT, while maintaining the cost low, recent research is mainly focused on improving (1) the reconstruction methods and (2) the acquisition systems. D-optimal sequential experimental design (D-SOED) offers a method to integrate these aspects into a common systematic framework. The transducer configuration is optimized to minimize the uncertainties in the estimated model parameters, and to reduce the time to solution by identifying redundancies in the data. This work presents a formulation to jointly optimize the experiment for transmission and reflection data and, in particular, to estimate the speed of sound and reflectivity of the tissue using either ray-based or wave-based imaging methods. Uncertainties in the parameters can be quantified by extracting properties of the posterior covariance operator, which is analytically computed by linearizing the forward problem with respect to the prior knowledge about parameters. D-SOED is first introduced by an illustrative toy example, and then applied to real data. This shows that the time to solution can be substantially reduced, without altering the final image, by selecting the most informative measurements.

Vaccine responses in patients with rheumatoid arthritis treated with certolizumab pegol: results from a single-blind randomized phase IV trial.

OBJECTIVE: To evaluate the humoral immune response to pneumococcal and influenza vaccination in adults with rheumatoid arthritis (RA) receiving certolizumab pegol (CZP). METHODS: In this 6-week, single-blind, placebo-controlled trial with optional 6-month open-label extension (NCT00993668), patients were stratified by concomitant methotrexate (MTX) use and randomized to receive CZP 400 mg (loading dose; according to CZP label) or placebo at weeks 0, 2, and 4. Pneumococcal (polysaccharide 23) and influenza vaccines were administered at Week 2. Satisfactory humoral immune response, defined as ≥2-fold titer increase in ≥3 of 6 pneumococcal antigens and ≥4-fold titer increase in ≥2 of 3 influenza antigens, were assessed independently 4 weeks after vaccination. RESULTS: Following pneumococcal vaccination, 62.5% of placebo patients and 54.5% of CZP patients without effective titers at baseline achieved a humoral response (difference in proportions was -8.0 percentage points; 95% CI -22.5 to 6.6%). Following influenza vaccination, 61.4% of placebo and 53.5% of CZP patients without effective titers at baseline achieved a humoral response (difference in proportions: -8.0 percentage points; 95% CI -22.9 to 7.0%). In all patients, including those with effective titers at baseline, 58.2% of placebo and 53.3% of CZP patients developed satisfactory pneumococcal titers, and 54.1% of placebo and 50.5% of CZP patients developed satisfactory influenza antibody titers. Vaccine responses to pneumococcal and influenza antigens were reduced similarly in both treatment groups with concomitant MTX use. CONCLUSION: Humoral immune responses to pneumococcal and influenza vaccination are not impaired when given during the loading phase of CZP treatment in patients with RA. (ClinicalTrials.gov NCT00993668).

Six steps from head to hand: a simulator based transfer oriented psychological training to improve patient safety.

UNLABELLED: The incidence of human errors in the field of medicine is high. Two strategies to increase patient safety are simulator training and crew resource management (CRM) seminars, psychological courses on human performance and error management. AIM: To establish a CRM course combining psychological training on human error with simulator training. METHODS: Evaluation of a new 1-day training approach targeting physicians, nurses, and paramedics. The course was divided into four modules focusing on situation awareness, task management, teamwork, and decision-making. Each of the modules was set up according to a new six-step approach. The course started with an introduction into good CRM behaviour and an instructor demonstration of a simulator scenario. The participants had to debrief the instructors regarding their human performance. Step 2 was a lecture about the psychological background, and the third step consisted of psychological exercises related to the topic of the module. A psychological exercise in a medical context (MiniSim) made up step 4, which involved a patient simulator. The last two steps were a simulator scenario and a debriefing, as in other simulator courses. A psychologist and a physician were the facilitators in all steps. Two pilot courses were evaluated. RESULTS: Seventeen evaluation questionnaires were received. All participants rated the course as good (10) and very good (7). The psychological exercises were highly valued (good, 5; very good, 11 participants). Thirteen participants agreed that the course content was related to their work. CONCLUSION: We established the first course curriculum combining psychological teaching with simulator training for healthcare professionals in emergency medicine. Similar concepts using the six-step approach can be applied to other medical specialties.