Adaptive coordination development in student anaesthesia teams: a longitudinal study.

Although adaptive coordination has been highlighted by several studies, research dealing with how adaptive coordination develops is still rare. Thus, the aim of this study was to investigate the development of coordination mechanisms and their task-related adaptation in a longitudinal observation of medical simulation-based training of final year students. We recorded six anaesthesia teams during a sequence of four task scenarios, and each scenario comprised of a routine and a complication phase. After trained observers rated sub-tasks within each scenario for explicit and implicit coordination, statistical analysis revealed a statistically significant effect of previous scenarios on coordination development in the routine phases. While the amount of explicit coordination decreased, implicit coordination increased, revealing adaptive coordination as a skill developed through repeated group interaction. We conclude that anaesthesia training should consider cost- and patient safety-benefits of implicit and explicit coordination and focus on adaptive coordination. PRACTITIONER SUMMARY: Group coordination is crucial to anaesthesia team performance. Results of this longitudinal observation of six anaesthesia teams during four medical simulation-based training scenarios document that teams develop adaptive patterns of coordination. This study also demonstrates that adaptive coordination is a trainable skill within crisis resource management training.

Validation of CFD predictions of flow in a 3D alveolated bend with experimental data.

Verifying numerical predictions with experimental data is an important aspect of any modeling studies. In the case of the lung, the absence of direct in vivo flow measurements makes such verification almost impossible. We performed computational fluid dynamics (CFD) simulations in a 3D scaled-up model of an alveolated bend with rigid walls that incorporated essential geometrical characteristics of human alveolar structures and compared numerical predictions with experimental flow measurements made in the same model by particle image velocimetry (PIV). Flow in both models was representative of acinar flow during normal breathing (0.82ml/s). The experimental model was built in silicone and silicone oil was used as the carrier fluid. Flow measurements were obtained by an ensemble averaging procedure. CFD simulation was performed with STAR-CCM+ (CD-Adapco) using a polyhedral unstructured mesh. Velocity profiles in the central duct were parabolic and no bulk convection existed between the central duct and the alveoli. Velocities inside the alveoli were approximately 2 orders of magnitude smaller than the mean velocity in the central duct. CFD data agreed well with those obtained by PIV. In the central duct, data agreed within 1%. The maximum simulated velocity along the centerline of the model was 0.5% larger than measured experimentally. In the alveolar cavities, data agreed within 15% on average. This suggests that CFD techniques can satisfactorily predict acinar-type flow. Such a validation ensure a great degree of confidence in the accuracy of predictions made in more complex models of the alveolar region of the lung using similar CFD techniques.

Global rainbow thermometry for droplet-temperature measurement.

Standard rainbow thermometry connects the scattering angle of the main rainbow maximum, generated by a single droplet, to the droplet's refractive index and thus to its temperature. Droplet nonsphericity influences the rainbow position and therefore degrades the quality of the droplet-temperature measurement. We propose global rainbow thermometry, which measures the average rainbow position that is created by multiple droplets and from which a mean temperature can be derived. The new technique aims at eliminating the nonsphericity effect. The principle of this method is presented, and a typical recorded image is discussed.

Rainbow phenomena applied to the measurement of droplet size and velocity and to the detection of nonsphericity.

An experimental method is presented that detects whether a droplet is spherical. The method is based on a comparison between two droplet diameters deduced from two different optical interference patterns observed in a rainbow that is created by a droplet scattering laser light. Experimental validation has been carried out with a CCD camera. Once a rainbow pattern has been identified as coming from a spherical droplet, we can derive a reliable droplet velocity and diameter from the same interference patterns, using theories for the rainbow that are valid only for spherical droplets. Preliminary experiments have been carried out with a laser beam and a photomultiplier.

Nonintrusive measurements of temperature and size of single falling raindrops.

A nonintrusive laser technique, based on the detection of a rainbow, is presented that permits one to determine simultaneously the temperature and size of droplets. Therefore the Airy theory for a rainbow and a calibration rainbow pattern at isothermal conditions are applied. Rainbow patterns coming from droplets in the millimeter range have been recorded on a linear CCD array. It has been found that the sphericity of the droplets plays an important role for this rainbow-based technique.