Effects of different VV ECMO blood flow rates on lung perfusion assessment by hypertonic saline bolus-based electrical impedance tomography.

OBJECTIVE: Our study aimed to investigate the effects of different extracorporeal membrane oxygenation (ECMO) blood flow rates on lung perfusion assessment using the saline bolus-based electrical impedance tomography (EIT) technique in patients on veno-venous (VV) ECMO. METHODS: In this single-centered prospective physiological study, patients on VV ECMO who met the ECMO weaning criteria were assessed for lung perfusion using saline bolus-based EIT at various ECMO blood flow rates (gradually decreased from 4.5 L/min to 3.5 L/min, 2.5 L/min, 1.5 L/min, and finally to 0 L/min). Lung perfusion distribution, dead space, shunt, ventilation/perfusion matching, and recirculation fraction at different flow rates were compared. RESULTS: Fifteen patients were included. As the ECMO blood flow rate decreased from 4.5 L/min to 0 L/min, the recirculation fraction decreased significantly. The main EIT-based findings were as follows. (1) Median lung perfusion significantly increased in region-of-interest (ROI) 2 and the ventral region [38.21 (34.93-42.16)% to 41.29 (35.32-43.75)%, p = 0.003, and 48.86 (45.53-58.96)% to 54.12 (45.07-61.16)%, p = 0.037, respectively], whereas it significantly decreased in ROI 4 and the dorsal region [7.87 (5.42-9.78)% to 6.08 (5.27-9.34)%, p = 0.049, and 51.14 (41.04-54.47)% to 45.88 (38.84-54.93)%, p = 0.037, respectively]. (2) Dead space significantly decreased, and ventilation/perfusion matching significantly increased in both the ventral and global regions. (3) No significant variations were observed in regional and global shunt. CONCLUSIONS: During VV ECMO, the ECMO blood flow rate, closely linked to recirculation fraction, could affect the accuracy of lung perfusion assessment using hypertonic saline bolus-based EIT.

A Dynamic Prediction Model for Renal Progression in Primary Membranous Nephropathy.

Objective: This study aimed to build and validate a practical web-based dynamic prediction model for predicting renal progression in patients with primary membranous nephropathy (PMN). Method: A total of 359 PMN patients from The First Affiliated Hospital of Fujian Medical University and 102 patients with PMN from The Second Hospital of Longyan between January 2018 to December 2023 were included in the derivation and validation cohorts, respectively. Renal progression was delineated as a decrease in eGFR of 30% or more from the baseline measurement at biopsy or the onset of End-Stage Renal Disease (ESRD). Multivariable Cox regression analysis was employed to identify independent prognostic factors. A web-based dynamic prediction model for renal progression was built and validated, and the performance was assessed using. An analysis of the receiver operating characteristic and the decision curve analysis. Results: In the derivation cohort, 66 (18.3%) patients experienced renal progression during the follow-up period (37.60 ± 7.95 months). The final prediction rule for renal progression included hyperuricemia (HR=2.20, 95%CI 1.26 to 3.86), proteinuria (HR=2.16, 95%CI 1.47 to 3.18), significantly lower serum albumin (HR=2.34, 95%CI 1.51 to 3.68) and eGFR (HR=1.96, 95%CI 1.47 to 2.61), older age (HR=1.85, 95%CI 1.28 to 2.61), and higher sPLA2R-ab levels (HR=2.08, 95%CI 1.43 to 3.18). Scores for each variable were calculated using the regression coefficients in the Cox model. The developed web-based dynamic prediction model, available online at http://imnpredictmodel1.shinyapps.io/dynnomapp, showed good discrimination (C-statistic = 0.72) and calibration (Brier score, P = 0.155) in the validation cohort. Conclusion: We developed a web-based dynamic prediction model that can predict renal progression in patients with PMN. It may serve as a helpful tool for clinicians to identify high-risk PMN patients and tailor appropriate treatment and surveillance strategies.

Effects of airway pressure release ventilation on lung physiology assessed by electrical impedance tomography in patients with early moderate-to-severe ARDS.

OBJECTIVE: The aim of this study was to investigate the physiological impact of airway pressure release ventilation (APRV) on patients with early moderate-to-severe acute respiratory distress syndrome (ARDS) by electrical impedance tomography (EIT). METHODS: In this single-center prospective physiological study, adult patients with early moderate-to-severe ARDS mechanically ventilated with APRV were assessed by EIT shortly after APRV (T0), and 6 h (T1), 12 h (T2), and 24 h (T3) after APRV initiation. Regional ventilation and perfusion distribution, dead space (%), shunt (%), and ventilation/perfusion matching (%) based on EIT measurement at different time points were compared. Additionally, clinical variables related to respiratory and hemodynamic condition were analyzed. RESULTS: Twelve patients were included in the study. After APRV, lung ventilation and perfusion were significantly redistributed to dorsal region. One indicator of ventilation distribution heterogeneity is the global inhomogeneity index, which decreased gradually [0.61 (0.55-0.62) to 0.50 (0.42-0.53), p < 0.001]. The other is the center of ventilation, which gradually shifted towards the dorsal region (43.31 ± 5.07 to 46.84 ± 4.96%, p = 0.048). The dorsal ventilation/perfusion matching increased significantly from T0 to T3 (25.72 ± 9.01 to 29.80 ± 7.19%, p = 0.007). Better dorsal ventilation (%) was significantly correlated with higher PaO2/FiO2 (r = 0.624, p = 0.001) and lower PaCO2 (r = -0.408, p = 0.048). CONCLUSIONS: APRV optimizes the distribution of ventilation and perfusion, reducing lung heterogeneity, which potentially reduces the risk of ventilator-induced lung injury.

Physiological Comparison of Airway Pressure Release Ventilation and Low Tidal Volume Ventilation in Acute Respiratory Distress Syndrome: A Randomized Controlled Trial.

BACKGROUND: The physiological effects of different ventilation strategies on patients with acute respiratory distress syndrome (ARDS) need to be better understood. RESEARCH QUESTION: In patients with ARDS under controlled mandatory ventilation, does airway pressure release ventilation (APRV) improve lung ventilation-perfusion matching and ventilation homogeneity compared to low tidal volume ventilation (LTV)? STUDY DESIGN AND METHODS: This study was a single-center randomized controlled trial. Patients with moderate-to-severe ARDS were randomly ventilated on APRV or LTV. Electrical impedance tomography (EIT) was utilized to assess lung ventilation and perfusion. EIT-based data and clinical variables related to respiratory and hemodynamic conditions were collected shortly before randomization (0h), and at 12 and 24 hours after randomization. RESULTS: A total of 40 subjects were included and randomized to the APRV or LTV group (20 per group). During the 24-hour trial period, patients on APRV exhibited significantly increased dorsal ventilation (difference value (24h-0h), median [25-75 percentiles]: 10.82% [2.62-13.74] vs 0.12% [-2.81-4.76], P = .017), decreased dorsal shunt (-4.67% [-6.83-0.59] vs 1.73% [-0.95-5.53], P = .008) and increased dorsal ventilation-perfusion matching (4.13% [-0.26-10.47] vs -3.29% [-5.05-2.81], P = .026) than those on LTV; no difference in ventral dead space was observed between study groups (P = .903). Additionally, two indicators of ventilation distribution heterogeneity: global inhomogeneity index significantly decreased, and center of ventilation significantly increased in the APRV group compared to the LTV group. Patients on APRV had significantly higher PaO2/FiO2, higher respiratory system static compliance (Crs) and lower PaCO2 than those on LTV at 24h. The cardiac output was comparable in both groups. INTERPRETATION: APRV, as compared to LTV, could recruit dorsal region, reduce dorsal shunt, increase dorsal ventilation-perfusion matching, and improve ventilation homogeneity of the lungs, leading to better gas exchange and Crs in patients with moderate-to-severe ARDS.

A fish bone induced aortic arch pseudoaneurysm in a male patient: A case report.

RATIONALE: Esophageal foreign body is a commonly seen in China. However, pseudoaneurysm of the aortic arch caused by ingestion of fish bones is a rare, life-threatening condition. PATIENT CONCERNS: A 71-year-old male was admitted to the Ear, Nose, and Throat department with a 4-day history of chest pain after eating fish. DIAGNOSES: After taking out the fish bone by rigid endoscopy, magnetic resonance imaging and computerized tomography angiography (CTA) scans revealed the presence of an aortic arch pseudoaneurysm, which was likely caused by the fish bone. INTERVENTIONS: A successful endovascular graft exclusion surgery was performed to block the aorta ulcer. OUTCOMES: The patient recovered and was discharged 20 days after hospitalization. The patient was healthy and had no fever or chest pain 4 months after discharge from the hospital. LESSONS: Esophageal foreign bodies may lead to life-threatening impairment of the aorta or other big arteries. When esophageal foreign bodies puncture the esophageal wall, especially in the second stenosis of the esophagus, an enhanced-contrast computed tomography scan or a CTA scan may be necessary to exclude any potential impairment of the arteries.