Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2020
Determination of cardiac output from pulse pressure contour during intra-aortic balloon pumping in patients with low ejection fraction.
Evaluation of a new Windkessel model based pulse contour method (WKflow) to calculate stroke volume in patients undergoing intra-aortic balloon pumping (IABP). Preload changes were induced by vena cava occlusions (VCO) in twelve patients undergoing cardiac surgery to vary stroke volume (SV), which was measured by left ventricular conductance volume method (SVlv) and WKflow (SVwf). Twelve VCO series were carried out during IABP assist at a 1:2 ratio and seven VCO series were performed with IABP switched off. ⋯ Changes in SVlv and SVwf were directionally concordant in response to VCO's and during severe arrhythmia. (R2 = 0.868). The SVwf and SVlv methods are interchangeable with respect to measuring absolute stroke volume as well as tracking changes in stroke volume. The precision of the non-calibrated WKflow method is about 10% which improved to 7.5% after one calibration per patient.
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J Clin Monit Comput · Apr 2020
Neuroanesthesiologists as interoperative neurophysiologists: a collaborative cognitive apprenticeship model of training in a community of clinical practice.
Directing intraoperative neurophysiologic monitoring (IONM) is a patient care activity for which no formal training programs exist, even though the need for well-trained practitioners is readily evident while caring for patients with diseases of the brain, spinal cord, spinal column, or nervous system. Here, we present the theoretical basis and institutional experience for a successful model of learning a new and complex set of skills: the medical direction of IONM. In a major academic institution, a clinical community of practice absorbed new members with professional backgrounds ranging from a recent neuroanesthesia fellowship to several decades of neuroanesthesia practice and trained them in a collaborative cognitive apprenticeship model to medically direct IONM. ⋯ The group has also trained four outside anesthesiologists-one of whom went on to become certified as a DABNM-who went on to develop the IONM program at a major children's hospital. This collaborative cognitive apprenticeship in anesthesiology to learn the medical direction of IONM is quite innovative as it integrates new members and expands the range of existing ones. In our model, the entire community is elevated by the reciprocal interactions of master clinicians, novice apprentices, and the community of practice.
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J Clin Monit Comput · Apr 2020
Comparative StudyComparison of cardiovascular parameter estimation methods using swine data.
In this study, new and existing methods of estimating stroke volume, cardiac output and total peripheral resistance from analysis of the arterial blood pressure waveform were tested over a wide range of conditions. These pulse contour analysis methods (PCMs) were applied to data obtained in six swine during infusion of volume, phenylephrine, dobutamine, isoproterenol, esmolol and nitroglycerine as well as during progressive hemorrhage. Performance of PCMs was compared using true end-ejection pressures as well as estimated end-ejection pressures. ⋯ The most accurate estimation of end-ejection was obtained when that fraction was set to 60% for the central arterial pressure and to 50% for the femoral and radial arterial pressures. When the estimated end-ejection measures were used for the PCMs that depend on end-ejection measures and when radial artery pressure was used as the input, only Wesseling's Corrected Impedance method and the modified Herd's method achieved statistically superior results. This study provides a systematic comparison of multiple PCMs' ability to estimate stroke volume, cardiac output, and total peripheral resistance and introduces a new method of estimating end-systole.
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J Clin Monit Comput · Apr 2020
Observational StudyDynamic properties of glucose complexity during the course of critical illness: a pilot study.
Methods to control the blood glucose (BG) levels of patients in intensive care units (ICU) improve the outcomes. The development of continuous BG levels monitoring devices has also permitted to optimize these processes. Recently it was shown that a complexity loss of the BG signal is linked to poor clinical outcomes. ⋯ The MSE analysis on time intervals revealed an entropy variation and allowed periodic BG signal complexity assessments. To highlight differences of MSE between each time interval we calculated the MSE complexity index defined as the area under the curve. This new approach could pave the way to future studies exploring new strategies aimed at restoring blood glucose complexity during the ICU stay.