Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2014
A case of anastomosis malposition of the Blalock-Taussig shunt diagnosed using perioperative transesophageal echocardiography monitoring.
The perioperative transesophageal echocardiography (TEE) is a very useful and minimal invasive monitoring not only for the cardiac anesthesia management, but also for the anesthesia management of the non-cardiac operations of the heart high risk patients. In this case report, we report a case of the urgent Blalock-Taussig shunt (BT shunt) operation for a small patient of Fallot's tetralogy with anoxic spell, which showed an atypical change of hemodynamics and SpO2 with the shunt opening. After the BT shunt anastomosis, the diastolic blood pressure decreased with the shunt opening, however, the expected rise of SpO2 was not provided. By the perioperative TEE monitoring with the single plane TEE transducer for neonate; UST-52110S (Hitachi Aloka Medical, Tokyo, Japan) with 4.5 mm in diameter, the cause of this atypical change of hemodynamics and SpO2 was diagnosed to be an accidental anastomosis malposition of the BT shunt to the right pulmonary vein and reported to the operator during the operation, and the operation was performed correctly.
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J Clin Monit Comput · Apr 2014
Clinical TrialPrediction of hypotension in the beach chair position during shoulder arthroscopy using pre-operative hemodynamic variables.
Since hypotension in beach chair position (BCP) can lead to catastrophic neurologic complications, the prediction of hypotension is a matter of concern in the BCP under general anesthesia. We investigated whether pre-induction values of mean arterial pressure (MAP), stroke volume variation (SVV), cardiac index (CI), and stroke volume index (SVI) can predict hypotension in BCP during general anesthesia. Forty healthy adult patients, aged 18-65 years, undergoing elective arthroscopic shoulder surgery, were enrolled. ⋯ The areas under the ROC curves for pre-induction values of MAP, CI, and SVI and post-induction value of SVV before a positional change were 0.556 (95% CI 0.373-0.739; p = 0.557), 0.735 (0.576-0.894; p = 0.014), 0.787 (0.647-0.926; p = 0.003), and 0.691 (0.525-0.857; p = 0.046), respectively. In this study, pre-induction values of CI and SVI and post-induction value of SVV before a positional change predicted hypotension in the BCP under general anesthesia. Our findings suggest that not only preload but also preoperative cardiac performances might be the important factors for the development of hypotension after a repositioning supine to the sitting during general anesthesia.
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J Clin Monit Comput · Apr 2014
Improved spatial resolution and electrogram wave direction independence with the use of an orthogonal electrode configuration.
To improve spatial resolution in recordings of intra-cardiac electrograms we characterized the utility of a novel configuration of two recording electrodes arranged perpendicularly to the endocardial surface. We hypothesized that this configuration denoted as orthogonal close unipolar (OCU) would combine advantages of conventional unipolar and contact bipolar (CBP) configurations. Electrical excitation was simulated in a computational model as arising from dipole current or from multi-wavelet reentry sources. ⋯ The difference between the actual dominant frequency in the tissue and that recorded by the electrodes was 0.44 ± 0.33 Hz for OCU, 0.58 ± 0.40 Hz for unipolar, and 0.62 ± 0.46 Hz for CBP. OCU confers improved spatial resolution compared with both unipolar and CBP electrode configurations. Unlike the case with CBP, OCU recordings are independent of excitation wave-front direction.
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J Clin Monit Comput · Apr 2014
Comparative StudyEvaluation of point-of-care analyzers' ability to reduce bias in conductivity-based hematocrit measurement during cardiopulmonary bypass.
Most point-of-care testing analyzers use the conductivity method to measure hematocrit (hct). During open-heart surgery, blood-conductivity is influenced by shifts in electrolyte and colloid concentrations caused by infusion media used, and this may lead to considerable bias in the hct measurement. We evaluated to what extent different analyzers correcting for 0, 1, 2, or 3 factors, respectively, compensated for this electrolyte/colloid interference: (1) the conductivity method with no correction (IRMA), (2) with a [Na(+)]-correction (GEM Premier 3000), (3) with a [Na(+)]/[K(+)]-correction (i-STAT), and (4) with a [Na(+)]/[K(+)]-correction in combination with an algorithm that estimates the protein dilution [i-STAT in cardiopulmonary bypass (CPB)-mode]. ⋯ In order of high to low electrolyte/colloid interference: the analyzer with no correction, [Na(+)]-correction, [Na(+)/]/[K(+)]-correction, and [Na(+)/]/[K(+)]/estimated protein-correction showed a change of bias from stage I to stage III of -3.9 ± 0.5, -3.4 ± 0.4, -2.1 ± 0.5, -0.3 ± 0.5%. We conclude that correcting for more parameters (Na(+), K(+), estimated protein) gives less bias, but residual bias remains even after [Na(+)/]/[K(+)]/estimated protein-correction. This suggests that a satisfactory algorithm should also correct for other colloidal factors than protein.
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J Clin Monit Comput · Apr 2014
Reliable real-time calculation of heart-rate complexity in critically ill patients using multiple noisy waveform sources.
Heart-rate complexity (HRC) has been proposed as a new vital sign for critical care medicine. The purpose of this research was to develop a reliable method for determining HRC continuously in real time in critically ill patients using multiple waveform channels that also compensates for noisy and unreliable data. Using simultaneously acquired electrocardiogram (Leads I, II, V) and arterial blood pressure waveforms sampled at 360 Hz from 250 patients (over 375 h of patient data), we evaluated a new data fusion framework for computing HRC in real time. ⋯ Furthermore, the fusion of waveform sources produced better error density distributions than those derived from individual waveforms. The data fusion framework was shown to provide in real-time a reliable continuously streamed HRC value, derived from multiple waveforms in the presence of noise and artifacts. This approach will be validated and tested for assessment of HRC in critically ill patients.