OBJECTIVE:Regional differences in lung volume have been described in adults with acute respiratory distress syndrome, but it remains unclear to what extent they occur in children. To quantify ...regional alveolar collapse that occurred during mechanical ventilation during a standardized suctioning maneuver, we evaluated regional and global relative impedance changes (relative ΔZ) in children with acute respiratory distress syndrome using electrical impedance tomography.
DESIGN:Prospective observational trial.
SETTING:A 30-bed pediatric intensive care unit.
PATIENTS:Six children with acute respiratory distress syndrome.
INTERVENTIONS:Standardized suctioning maneuver.
MEASUREMENTS AND MAIN RESULTS:By comparing layers from nondependent (layers 1 and 2) to dependent lung areas (layers 3 and 4), it was demonstrated that the middle layers (2 and 3) had the greatest ventilation-induced change in relative ΔZ; layer 4 showed the least ventilation-induced change in relative ΔZ. During suctioning, layers 1, 2, and 3 showed a negative change in relative ΔZ, whereas layer 4 showed no significant change in relative ΔZ. The derecruitment-induced change in relative ΔZ representing the lung-volume loss was −9.8 (−3.0 mL/kg) during the first suctioning maneuver, −16.1 (−5.4 mL/kg) during the second, and −21.7 (−7.4 mL/kg) during the third. The ventilation-induced change in relative ΔZ during mechanical ventilation remained unchanged after suctioning (mean change in relative ΔZ before vs. after suctioning, 40.1 ± 9.1 vs. 41.4 ± 10.8; p = .30). Dynamic compliance was 11.8 ± 6.1 mL·cm H2O before and 11.8 ± 6.9 mL·cm H2O after the suctioning sequence (p = .90).
CONCLUSIONS:Considerable regional heterogeneity was present during ventilation and a derecruitment maneuver. Significantly lower change in relative ΔZ in the most dependent lung regions suggests alveolar collapse during ventilation before suctioning.
FEM electrode refinement for electrical impedance tomography Grychtol, Bartlomiej; Adler, Andy
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC),
01/2013, Letnik:
2013
Conference Proceeding, Journal Article
Electrical Impedance Tomography (EIT) reconstructs images of electrical tissue properties within a body from electrical transfer impedance measurements at surface electrodes. Reconstruction of EIT ...images requires the solution of an inverse problem in soft field tomography, where a sensitivity matrix, J, of the relationship between internal changes and measurements is calculated, and then a pseudo-inverse of J is used to update the image estimate. It is therefore clear that a precise calculation of J is required for solution accuracy. Since it is generally not possible to use analytic solutions, the finite element method (FEM) is typically used. It has generally been recommended in the EIT literature that FEMs be refined near electrodes, since the electric field and sensitivity is largest there. In this paper we analyze the accuracy requirement for FEM refinement near electrodes in EIT and describe a technique to refine arbitrary FEMs.
The strathclyde brain computer interface Valsan, G.; Grychtol, B.; Lakany, H. ...
2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society,
01/2009, Letnik:
2009
Conference Proceeding, Journal Article
Odprti dostop
Brain-computer interfaces (BCI) offer potential for individuals with a variety of motor and sensory disabilities to control their environment, communicate, and control mobility aids. However, the key ...to BCI usability rests in being able to extract relevant time varying signals that can be classified into usable commands in real time. This paper reports the first success of the Strathclyde BCI controlling a wheelchair on-line in Virtual Reality. Surface EEG recorded during wrist movement in two different directions were classified and used to control a wheelchair within a virtual reality environment. While principal component analysis was used for feature vector quantiser distances were used for classification. Classification success rates between 68% and 77% were obtained using these relatively simple methods.
Electrical impedance tomography (EIT) has undergone 30 years of development. Functional chest examinations with this technology are considered clinically relevant, especially for monitoring regional ...lung ventilation in mechanically ventilated patients and for regional pulmonary function testing in patients with chronic lung diseases. As EIT becomes an established medical technology, it requires consensus examination, nomenclature, data analysis and interpretation schemes. Such consensus is needed to compare, understand and reproduce study findings from and among different research groups, to enable large clinical trials and, ultimately, routine clinical use. Recommendations of how EIT findings can be applied to generate diagnoses and impact clinical decision-making and therapy planning are required. This consensus paper was prepared by an international working group, collaborating on the clinical promotion of EIT called TRanslational EIT developmeNt stuDy group. It addresses the stated needs by providing (1) a new classification of core processes involved in chest EIT examinations and data analysis, (2) focus on clinical applications with structured reviews and outlooks (separately for adult and neonatal/paediatric patients), (3) a structured framework to categorise and understand the relationships among analysis approaches and their clinical roles, (4) consensus, unified terminology with clinical user-friendly definitions and explanations, (5) a review of all major work in thoracic EIT and (6) recommendations for future development (193 pages of online supplements systematically linked with the chief sections of the main document). We expect this information to be useful for clinicians and researchers working with EIT, as well as for industry producers of this technology.
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