Respiratory monitoring with electrical impedance tomography for lung protective ventilation and alveolar recruitment maneuver in a patient with a single lung transplant and early graft dysfunction

Review of electrical impedance tomography in the pediatric patient

Electrical impedance tomography (EIT) is a new method of monitoring non-invasive mechanical ventilation, at the bedside and useful in critically ill patients. It allows lung monitoring of ventilation and perfusion, obtaining images that provide information on lung function. It is based on the physical principle of impedanciometry or the body's ability to conduct an electrical current. Various studies have shown its usefulness both in adults and in pediatrics in respiratory distress syndrome, pneumonia and atelectasis in addition to pulmonary thromboembolism and pulmonary hypertension by also providing information on pulmonary perfusion, and may be very useful in perioperative medicine; especially in pediatrics avoiding repetitive imaging tests with ionizing radiation.

Regional Ventilation-Perfusion Matching by Electrical Impedance Tomography After Single Lung Transplant

Single lung transplantation (LUTX) can be the last therapeutic option for a growing cohort of patients suffering from end-stage respiratory failure. Postoperative ventilatory management of single LUTX recipients is challenged by the coexistence of the diseased native lung and a healthy-but fragile-graft. In this case report, in a single LUTX recipient with idiopathic pulmonary fibrosis, regional ventilation ( ), perfusion ( ), and / matching and subsequent measurement of shunt fraction ( Qs / Qt ) and alveolar dead space ( Vd / Vt ) were obtained by integrating electrical impedance tomography (EIT) with volumetric capnography and pulmonary thermodilution technique. Although the preoperative pulmonary scintigraphy showed predominant right lung perfusion (79.8% vs. 20.2%), the EIT documented the postoperative re-establishment of between the lungs (demonstrating the adequate functioning of vascular anastomoses), the diversion of to the graft and similar global Qs / Qt (17%) and Vd / Vt (29%) between native and graft lung. Electrical impedance tomography mapping allowed regional Qs / Qt and Vd / Vt assessment: the native right lung had a completely deranged distribution of and ( Qs / Qt 25%, Vd / Vt 46%), whereas the graft showed normal coupling of and ( Qs / Qt 8%, Vd / Vt 12%). Electrical impedance tomography may allow noninvasive, repeatable, bedside assessments of the lung / coupling after single LUTX.

Roles of electrical impedance tomography in lung transplantation

Lung transplantation is the preferred treatment method for patients with end-stage pulmonary disease. However, several factors hinder the progress of lung transplantation, including donor shortages, candidate selection, and various postoperative complications. Electrical impedance tomography (EIT) is a functional imaging tool that can be used to evaluate pulmonary ventilation and perfusion at the bedside. Among patients after lung transplantation, monitoring the graft’s pulmonary function is one of the most concerning issues. The feasible application of EIT in lung transplantation has been reported over the past few years, and this technique has gained increasing interest from multidisciplinary researchers. Nevertheless, physicians still lack knowledge concerning the potential applications of EIT in lung transplantation. We present an updated review of EIT in lung transplantation donors and recipients over the past few years, and discuss the potential use of ventilation- and perfusion-monitoring-based EIT in lung transplantation.

Assessment of Lung Recruitment by Electrical Impedance Tomography and Oxygenation in ARDS Patients

We hypothesized that not all patients with appreciably recruited lung tissue during a recruitment maneuver (RM) show significant improvement of oxygenation. In the present study, we combined electrical impedance tomography (EIT) with oxygenation measurements to examine the discrepancies of lung ventilation and perfusion versus oxygenation after RM.A 2-minute RM (20 cm H2O positive end-expiratory pressure [PEEP] + 20 cm H2O pressure control) was prospectively conducted in 20 acute respiratory distress syndrome patients from January 2014 to December 2014. A decremental PEEP trial was performed to select the PEEP level after RM. A positive response to RM was identified as PaO2 + PaCO2 ≥400 mm Hg. Relative differences in the distribution of ventilation and perfusion in the most dependent region of interest (ROI4) were monitored with EIT and denoted as the ventilation-perfusion index.Ten patients were found to be responders and 10 patients to be nonresponders. No significant difference in baseline PaO2/FiO2 was observed between nonresponders and responders. A significantly higher PaO2/FiO2 ratio during RM and higher PEEP set after PEEP titration were recorded in responders. In both responders and nonresponders, the proportion of ventilation distributed in ROI4 compared with the global value was lower than the cardiac-related activity before RM, but this situation was reversed after RM (P < 0.01 in each group). Six out of 10 nonresponders exhibited a remarkable increase in ventilation in ROI4. A significant difference in the relative ventilation-perfusion index was found between the patients with remarkable and insufficient lung tissue reopening in the nonresponder group (P < 0.01).A discrepancy between lung tissue reopening and oxygenation improvement after RM was observed. EIT has the potential to evaluate the efficacy of RM by combining oxygenation measurements.