Journal of clinical monitoring and computing
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The purpose of this concept study was to investigate the possibility of automatic mean arterial pressure (MAP) regulation in a porcine heart-beating brain death (BD) model. Hemodynamic stability of BD donors is necessary for maintaining acceptable quality of donated organs for transplantation. Manual stabilization is challenging, due to the lack of vasomotor function in BD donors. ⋯ The system was able to prevent hypertension, exceeding a reference of 100 mmHg by more than 10%, during 98% of a 12 h experiment. This early work demonstrates feasibility of the investigated modelling and control synthesis approach, for the purpose of maintaining normotension in a porcine BD model. There remains a need to characterize individual variability, in order to ensure robust performance over the expected population.
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J Clin Monit Comput · Jun 2018
Pre-anesthetic stroke volume variation can predict cardiac output decrease and hypotension during induction of general anesthesia.
This study aimed to assess the reliability of stroke volume variation (SVV) in predicting cardiac output (CO) decrease and hypotension during induction of general anesthesia. Forty-five patients undergoing abdominal surgery under general anesthesia were enrolled. Before induction of anesthesia, patients were required to maintain deep breathing (6-8 times/min), and pre-anesthetic SVV was measured for 1 min by electrical cardiometry. ⋯ Patients with lower SVV exhibited a significantly slower onset and lower incidence of decreased CO than those with higher SVV (p = 0.003). Multivariate logistic regression analysis indicated high pre-anesthetic SVV as being an independent risk factor for decreased CO and hypotension (odds ratio, 1.43 and 1.16, respectively). In conclusions, pre-anesthetic SVV can predict incidence of decreased CO and hypotension during induction of general anesthesia.
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J Clin Monit Comput · Jun 2018
Closed-loop mechanical ventilation for lung injury: a novel physiological-feedback mode following the principles of the open lung concept.
Adherence to low tidal volume (VT) ventilation and selected positive end-expiratory pressures are low during mechanical ventilation for treatment of the acute respiratory distress syndrome. Using a pig model of severe lung injury, we tested the feasibility and physiological responses to a novel fully closed-loop mechanical ventilation algorithm based on the "open lung" concept. Lung injury was induced by surfactant washout in pigs (n = 8). ⋯ Using the "open lung" approach, tidal volume delivery required low lung distending pressures, increased recruitment and ventilation of dorsal lung regions and improved arterial blood oxygenation. Physiological feedback closed-loop mechanical ventilation according to the principles of the open lung concept is feasible and provides low tidal volume ventilation without human intervention. Of importance, the "open lung approach"-ventilation improved gas exchange and reduced lung driving pressures by opening atelectasis and shifting of ventilation to dorsal lung regions.
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J Clin Monit Comput · Jun 2018
Correction to: Changes in transcranial motor evoked potentials during hemorrhage are associated with increased serum propofol concentrations.
In the original publication of the article, the corresponding author inadvertently omitted one of the co-authors in the author group. The corrected author group is given in this erratum.
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J Clin Monit Comput · Jun 2018
Photoplethysmography for blood volumes and oxygenation changes during intermittent vascular occlusions.
Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO[Formula: see text]) is calculated noninvasively. However, the PPG waveform contains other significant physiological information that can be used in conjunction to SpO[Formula: see text] for the assessment of oxygenation and blood volumes changes. ⋯ A[Formula: see text] indicated significant changes for occlusion pressures exceeding 20 mmHg (p < 0.05) and correlation with tissue oxygenation changes measured by NIRS, while SpO[Formula: see text] had significant changes after 40 mmHg (p < 0.05). Relative changes in haemoglobin concentrations can be estimated from PPG signals and they showed a good level of accuracy in the detection of perfusion and oxygenation changes induced by different degrees of intermittent vascular occlusions. These results can open up to new applications of the PPG waveform in the detection of blood volumes and oxygenation changes.