Articles: ventilators.
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Case Reports
Bedside Diagnosis of Pulmonary Embolism Using Electrical Impedance Tomography: A Case Report.
Electrical impedance tomography (EIT) is an emerging imaging modality that can be used to diagnose ventilatory and intrathoracic perfusion mismatches in unstable patients at the bedside. We present a case of a postoperative hypoxic patient in the intensive care unit (ICU) who was too unstable for transport for computed tomography (CT) imaging but was diagnosed and treated for a pulmonary embolism using EIT at the bedside. After the patient clinically improved, CT imaging confirmed the pulmonary embolism diagnosis. EIT is a promising diagnostic tool that may have great utility in ICUs, where it can be safely applied at the bedside.
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Critical care medicine · Jul 2022
Lung Ultrasound and Electrical Impedance Tomography During Ventilator-Induced Lung Injury.
Lung damage during mechanical ventilation involves lung volume and alveolar water content, and lung ultrasound (LUS) and electrical impedance tomography changes are related to these variables. We investigated whether these techniques may detect any signal modification during the development of ventilator-induced lung injury (VILI). ⋯ Data suggest as follows. First, what determines the LUS score is the ratio between water and gas and not water alone. Therefore, caution is needed when an improvement of LUS score follows a variation of the lung gas content, as after a PEEP increase. Second, what determines the end-expiratory difference in lung impedance is the strain level that may disrupt the intercellular junction, therefore altering lung impedance. In addition, the increase in extravascular lung water during VILI development contributed to the observed decrease in impedance.
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Critical-care ventilators provide patient circuit compensation (CC) to counteract the loss of volume due to patient circuit compliance. No studies show the effect of inspiratory efforts (indicating maximal value of the muscle pressure waveforms [Pmax]) on CC function. The goal of this study was to determine how Pmax affects volume delivery with or without CC for both volume control continuous mandatory ventilation with set-point targeting scheme (VC-CMVs) and pressure control continuous mandatory ventilation with adaptive targeting scheme (PC-CMVa) modes on the Servo-u ventilator. ⋯ CC corrected the delivered VT for volume lost due to compression in the patient circuit as expected. This compensation volume decreases as airway pressure drops due to patient Pmax.