Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2019
Assessment of cerebral hemodynamic parameters using pulsatile versus non-pulsatile cerebral blood outflow models.
Prior methods evaluating the changes in cerebral arterial blood volume (∆CaBV) assumed that brain blood transport distal to big cerebral arteries can be approximated with a non-pulsatile flow (CFF) model. In this study, a modified ∆CaBV calculation that accounts for pulsatile blood flow forward (PFF) from large cerebral arteries to resistive arterioles was investigated. The aim was to assess cerebral hemodynamic indices estimated by both CFF and PFF models while changing arterial blood carbon dioxide concentration (EtCO2) in healthy volunteers. ⋯ Our results suggest that the pulsatile flow forward model better reflects changes in CrCP and in τ induced by controlled alterations in EtCO2.
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J Clin Monit Comput · Feb 2019
Multicenter StudyForewarning of hypotensive events using a Bayesian artificial neural network in neurocritical care.
Traumatically brain injured (TBI) patients are at risk from secondary insults. Arterial hypotension, critically low blood pressure, is one of the most dangerous secondary insults and is related to poor outcome in patients. The overall aim of this study was to get proof of the concept that advanced statistical techniques (machine learning) are methods that are able to provide early warning of impending hypotensive events before they occur during neuro-critical care. ⋯ With a decision threshold of 0.3, > 15 min warning of patient instability can be achieved. We have shown, using advanced machine learning techniques running in a live neuro-critical care environment, that it would be possible to give neurointensive teams early warning of potential hypotensive events before they emerge, allowing closer monitoring and earlier clinical assessment in an attempt to prevent the onset of hypotension. The multi-centre clinical infrastructure developed to support the clinical studies provides a solid base for further collaborative research on data quality, false positive correction and the display of early warning data in a clinical setting.
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J Clin Monit Comput · Feb 2019
Observational StudyContinuous noninvasive arterial blood pressure monitoring using the vascular unloading technology during complex gastrointestinal endoscopy: a prospective observational study.
The innovative vascular unloading technology (VUT) allows continuous noninvasive arterial blood pressure (AP) monitoring. We aimed to investigate whether the VUT enables AP changes to be detected earlier compared with intermittent AP monitoring in patients undergoing gastrointestinal endoscopy. In this prospective observational study, we recorded continuous AP measurements with the VUT (CNAP system; CNSystems Medizintechnik AG, Graz, Austria) and intermittent AP measurements with upper arm cuff oscillometry in 90 patients undergoing complex gastrointestinal endoscopy (Department of Interventional Endoscopy at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany). ⋯ Continuous noninvasive AP monitoring using the VUT enables hypotensive phases to be detected earlier compared with intermittent AP monitoring during complex gastrointestinal endoscopy. These hypotensive phases may be missed or only belatedly recognized with intermittent AP monitoring. Continuous noninvasive AP measurement facilitates detecting hemodynamic instability more rapidly and therefore may improve patient safety.
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J Clin Monit Comput · Feb 2019
Observational StudyComplexity of preoperative blood pressure dynamics: possible utility in cardiac surgical risk assessment.
Complexity measures are intended to assess the cardiovascular system's capacity to respond to stressors. We sought to determine if decreased BP complexity is associated with increased estimated risk as obtained from two standard instruments: the Society of Thoracic Surgeons' (STS) Risk of Mortality and Morbidity Index and the European System for Cardiac Operative Risk Evaluation Score (EuroSCORE II). In this observational cohort study, preoperative systolic, diastolic, mean (MAP) and pulse pressure (PP) time series were derived in 147 patients undergoing cardiac surgery. ⋯ The mean and SD of BP time series were not significantly associated with the risk index except for a positive association with the SD of the diastolic BP. Lower preoperative BP complexity was associated with a higher estimated risk of adverse cardiovascular outcomes and may provide a novel approach to assessing cardiovascular risk. Future studies are needed to determine whether dynamical risk indices can improve current risk prediction tools.
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J Clin Monit Comput · Feb 2019
Observational StudyQuantitative computed tomography in comparison with transpulmonary thermodilution for the estimation of pulmonary fluid status: a clinical study in critically ill patients.
Extravascular lung water (index) (EVLW(I)) can be estimated using transpulmonary thermodilution (TPTD). Computed tomography (CT) with quantitative analysis of lung tissue density has been proposed to quantify pulmonary edema. We compared variables of pulmonary fluid status assessed using quantitative CT and TPTD in critically ill patients. ⋯ There was no significant correlation between TVI and EVLWI before CT, EVLWI after CT, or mean EVLWI. CT-derived variables did not predict elevated TPTD-derived EVLWI values. In unselected critically ill patients, variables of pulmonary fluid status assessed using quantitative CT cannot be used to predict EVLWI.