BACKGROUND: End-expiratory lung volume (EELV) has been observed to decrease in acute respiratory distress syndrome (ARDS). Yet, research investigating EELV in patients with COVID-19 associated ARDS (CARDS) remains limited. It is unclear whether EELV could serve as a potential metric for monitoring disease progression and identifying patients with ARDS at increased risk of adverse outcomes.
METHODS: This retrospective study included mechanically ventilated patients diagnosed with CARDS during the initial phase of epidemic control in Shanghai. EELV was measured using the nitrogen washout-washin technique within 48 h post-intubation, followed by regular assessments every 3-4 days. Chest CT scans, performed within a 24-hour window around each EELV measurement, were analyzed using AI software. Differences in patient demographics, clinical data, respiratory mechanics, EELV, and chest CT findings were assessed using linear mixed models (LMM).
RESULTS: Out of the 38 patients enrolled, 26.3% survived until discharge from the ICU. In the survivor group, EELV, EELV/predicted body weight (EELV/PBW) and EELV/predicted functional residual capacity (EELV/preFRC) were significantly higher than those in the non-survivor group (survivor group vs. non-survivor group: EELV: 1455 vs. 1162 ml, P = 0.049; EELV/PBW: 24.1 vs. 18.5 ml/kg, P = 0.011; EELV/preFRC: 0.45 vs. 0.34, P = 0.005). Follow-up assessments showed a sustained elevation of EELV/PBW and EELV/preFRC among the survivors. Additionally, EELV exhibited a positive correlation with total lung volume and residual lung volume, while demonstrating a negative correlation with lesion volume determined through chest CT scans analyzed using AI software.
CONCLUSIONS: EELV is a useful indicator for assessing disease severity and monitoring the prognosis of patients with CARDS.

OBJECTIVE: To develop a mediastinal shift angle (MSA) measurement method applicable to right-sided congenital diaphragmatic hernia (RCDH) in fetal MRI and to validate the predictive value of MSA in RCDH.
METHODS: Twenty-seven fetuses with isolated RCDH and 53 controls were included in our study. MSA was measured on MRI axial image at the level of four-chamber view of the fetal heart. The angle between the sagittal midline landmark line and the left boundary landmark line touching tangentially the lateral wall of the left ventricle was used to quantify MSA for RCDH. Appropriate statistical analyses were performed to determine whether MSA can be regarded as a valid predictive tool for postnatal outcomes. Furthermore, predictive performance of MSA was compared with that of lung area to head circumference ratio (LHR), observed/expected LHR (O/E LHR), total fetal lung volume (TFLV), and observed/expected TFLV (O/E TFLV).
RESULTS: MSA was significantly higher in the RCDH group than in the control group. MSA, LHR, O/E LHR, TFLV, and O/E TFLV were all correlated with postnatal survival, pulmonary hypertension (PH), and extracorporeal membrane oxygenation (ECMO) therapy (p < 0.05). Value of the AUC demonstrated good predictive performance of MSA for postnatal survival (0.901, 95%CI: (0.781-1.000)), PH (0.828, 95%CI: (0.661-0.994)), and ECMO therapy (0.813, 95%CI: (0.645-0.980)), which was similar to O/E TFLV but slightly better than TFLV, O/E LHR, and LHR.
CONCLUSIONS: We developed a measurement method of MSA for RCDH for the first time and demonstrated that MSA could be used to predict postnatal survival, PH, and ECMO therapy in RCDH.
CONCLUSIONS: Newly developed MRI assessment method of fetal MSA in RCDH offers a simple and effective risk stratification tool for patients with RCDH.
CONCLUSIONS: • We developed a measurement method of mediastinal shift angle for right-sided congenital diaphragmatic hernia for the first time and demonstrated its feasibility and reproducibility. • Mediastinal shift angle can predict more prognostic information other than survival in right-sided congenital diaphragmatic hernia with good performance. • Mediastinal shift angle can be used as a simple and effective risk stratification tool in right-sided congenital diaphragmatic hernia to improve planning of postnatal management.

暂无摘要。

The objective was to explore the relationships between computed tomography (CT) lung volume parameters and pulmonary function test (PFT) indexes and develop predictive scores to predict PFT indexes in Chinese preoperative patients suspected with lung cancer. Preoperative patients suspected with lung cancer aged 18 years or more and examined by chest CT scan and PET were consecutively recruited from April to August 2020, at Yunnan Cancer Hospital. CT and PET data were selected from medical record. Pearson correlation was used to explore the relationships between CT parameters and PFT indexes. Predictive scores of PFT indexes were developed from unstandardized coefficients of linear regression models of using CT parameters as predictors. The assessments of predictive ability of scores were conducted by receiver operating characteristics curves. A total of 124 preoperative patients suspected with lung cancer participated in this study. Total lung volume significantly correlated with total lung capacity (r = 0.708), residual volume (r = 0.411), forced expiratory volume in one second (FEV1, r = 0.535), forced vital capacity (FVC, r = 0.687), and FEV1/FVC (r = -0.319). Percent of low attenuation volume significantly correlated with total lung capacity (r = 0.200), residual volume (r = 0.215), FEV1 percentage of predictive value (FEV1%, r = -0.204) and FEV1/FVC (r = -0.345). Four predictive scores for FEV1, FEV1%, FEV1/FVC and FVC% were developed. The area under the curve of receiver operating characteristics for FEV1 <2L, FEV1% <80%, FEV1/FVC <80% and FVC% <80% were 0.856, 0.667, 0.749 and 0.715, respectively. A prediction of poor lung function in preoperative patients suspected with lung cancer, using total lung volume and percent of low attenuation volume was possible. The predictive scores should be further evaluated for external validity.

BACKGROUND: Although lung volumes are usually normal in individuals with chronic thromboembolic pulmonary hypertension (CTEPH), approximately 20%-29% of patients exhibit a restrictive pattern on pulmonary function testing.
OBJECTIVE: To quantify longitudinal changes in lung volume and cardiac cross-sectional area (CSA) in patients with CTEPH.
METHODS: In a retrospective cohort study of patients seen in our hospital between January 2012 and December 2019, we evaluated 15 patients with CTEPH who had chest computed tomography (CT) performed at baseline and after at least 6 mo of therapy. We matched the CTEPH cohort with 45 control patients by age, sex, and observation period. CT-based lung volumes and maximum cardiac CSAs were measured and compared using the Wilcoxon signed-rank test and the Mann-Whitney u test.
RESULTS: Total, right lung, and right lower lobe volumes were significantly reduced in the CTEPH cohort at follow-up vs baseline (total, P = 0.004; right lung, P = 0.003; right lower lobe; P = 0.01). In the CTEPH group, the reduction in lung volume and cardiac CSA was significantly greater than the corresponding changes in the control group (total, P = 0.01; right lung, P = 0.007; right lower lobe, P = 0.01; CSA, P = 0.0002). There was a negative correlation between lung volume change and cardiac CSA change in the control group but not in the CTEPH cohort.
CONCLUSIONS: After at least 6 mo of treatment, CT showed an unexpected loss of total lung volume in patients with CTEPH that may reflect continued parenchymal remodeling.

Mechanical ventilation has long been recognized as the most vital therapy for patients with ARDS. Compared with lung-protective ventilation, debates that involve the open lung strategy, which consists primarily of the lung recruitment maneuver and higher PEEP, have never been resolved. In terms of the beneficial and detrimental effects of this aggressive maneuver, appraisal of lung recruitment is essential for intensivists to make clinical decisions. This review aimed to clarify how to assess the potential for lung recruitment based on respiratory mechanics when using the pressure-volume curve or loop method and end-expiratory lung volume-static compliance of the respiratory system method. However, their limitations related to excessive generalization, accuracy, and identification of cutoff values cannot be omitted. Finally, future studies are warranted to combine these classic methods with newly invented techniques to achieve safer and more effective lung recruitment.

The aim of this study was to investigate the influence of corrective surgery on thoracic spinal posttubercular kyphosis (PTK) with respect to lung volume and pulmonary function.
This was a retrospective study of 126 patients (72 males and 54 females) who underwent posterior vertebral column resection (PVCR) for severe thoracic spinal PTK between September 2013 and June 2020. The patients\' spinal parameters, results of their pulmonary function test (PFT), and CT-based 3D lung volume were recorded and analyzed preoperatively and at final follow-up. The correlation of kyphosis correction with the PFT and lung volume was evaluated.
The mean local kyphosis decreased from 112.5° to 37.2°, and the mean local scoliosis decreased from 20.9° to 5.2°; C2-7 lordosis, thoracic kyphosis, and lumbar lordosis also significantly improved after surgery. The mean CT-based lung volume significantly increased from 2.9 L preoperatively to 3.6 L at the final follow-up. The indices of PFT, including forced vital capacity (FVC), percent predicted FVC, total lung capacity, and forced expiratory volume in 1 second, were also significantly improved, and 60 patients with pulmonary dysfunction recovered to normal at the final follow-up. The correlation analysis revealed that the correction of local kyphosis was closely correlated with the improvement in PFT and the increase in lung volume.
PVCR cannot only effectively realign the spine in patients with severe thoracic spinal PTK deformity but also significantly improve pulmonary function. Adequate local kyphosis correction should be highly valued, as it is a key factor in increasing lung volume.

OBJECTIVE: To compare the effects of respiratory function on different degrees of reduced thoracic volume and evaluate the tolerance of rats with reduced thoracic volume, and to assess the feasibility of thoracic volume as a measure of the severity of rib fractures.
METHODS: A total of 24 10-week-old female Sprague-Dawley (SD) rats were randomly divided into four groups (n = 6 in each group) according to the displacement degree of bilateral rib fractures (2, 4, 6, and 8 mm). The respiratory function of the rats（Tidal volume, Inspiration time, Expiration time, Breath rate, Minute volume, Peak inspiration flow) measured via whole-body barometric plethysmography before and after operation for 14 consecutive days. Respiratory function parameters of each group were analyzed. Chest CT scans were performed before and 14 days after operation, after that we reconstructed three-dimensional of the thoracic and lung and measured their volumes by computer software. We calculated the percentage of thoracic and lung volume reduction after operation.
RESULTS: At the 14th day after the operation, the decline of thoracic volume rates of in the 2, 4, 6, and 8 mm groups were 5.20%, 9.01%, 16.67%, and 20.74%, respectively. The 8 mm group showed a significant reduction in lung volume. The postoperative tidal volumes were lower in each of the groups than the baseline values before the operation. The tidal volume of the 2 mm group gradually recovered after the operation and returned to a normal level (1.54 ± 0.07 mL) at 14th day after the operation. The tidal volume of the 4, 6, and 8 mm groups recovered gradually after the operation, but did not return to baseline level at the 14th day. In particular, the tidal volume of the 8 mm group was significantly lower than that of the other groups during the 14 days (1.23 ± 0.12 mL, p < 0.05). There were no significant changes in the inspiratory and expiratory times, peak inspiratory and expiratory flows, respiratory rate, and minute ventilation during the 14 days after the operation in each group.
CONCLUSIONS: Displaced rib fractures lead to thoracic collapse and reduced thoracic volume, which can affect tidal volume in rats. The greater the decrease of thoracic volume, the more obvious the decrease of early tidal volume. The thoracic volume can be used as an objective parameter to evaluate the severity of multiple rib fractures. Early operation to restore thoracic volume may improve early respiratory function. Decreased thoracic volume affected respiratory function and can be compensated and recovered in the long term.

BACKGROUND: Functional lung volume (FLV) obtained from computed tomography images was a breakthrough for lung imaging and functional assessment. We compared the accuracy of the FLV measurement method and the segment-counting (SC) method in predicting postoperative pulmonary function.
METHODS: A total of 113 patients who underwent two thoracoscopic surgeries were enrolled in our study. We predicted postoperative pulmonary function by the FLV measurement method and the SC method. Novel formulas based on the FLV measurement method were established using linear regression equations between the factors affecting pulmonary function and the measured values.
RESULTS: The predicted postoperative forced vital capacity (ppoFVC) and forced expiratory volume in 1 s (ppoFEV1) measured by the 2 methods showed high concordance between the actual postoperative forced vital capacity (postFVC) and the forced expiratory volume in 1 s (postFEV1) [r = 0.762, P < 0.001 (FLV method) and r = 0.759, P < 0.001 (SC method) for FVC; r = 0.790, P < 0.001 (FLV method) and r = 0.795, P < 0.001 (SC method) for FEV1]. Regression analysis showed that the measured preoperative pulmonary function parameters (FVC, FEV1) and the ratio of reduced FLV to preoperative FLV were significantly associated with the actual postoperative values and could predict these parameters (all P < 0.001). The feasibility of using these equations [postFVC = 0.8 × FVC - 0.784 × ΔFLV/FLV + 0.283 (R2 = 0.677, RSD = 0.338), postFEV1 = 0.766 × FEV1 - 0.694 × ΔFLV/FLV + 0.22 (R2 = 0.743, RSD = 0.265)] to predict the pulmonary function parameters after wedge resection was also verified.
CONCLUSIONS: The new FLV measurement method is valuable for predicting postoperative pulmonary function in patients undergoing lung resection surgery, with accuracy and consistency similar to those of the conventional SC method.

OBJECTIVE: To investigate the predictive value of mediastinal shift angle (MSA) in congenital diaphragmatic hernia (CDH).
METHODS: A retrospective analysis was performed on 87 fetuses with prenatally diagnosed left-sided CDH (LCDH) and 88 controls. MSA was measured on magnetic resonance imaging (MRI). Lung area to head circumference ratio (LHR), ratio of the observed/expected LHR (O/E LHR), total fetal lung volume (TFLV), and observed/expected total fetal lung volume (O/E TFLV) were also measured. Correlation of MSA with pulmonary hypertension (PH), extracorporeal membrane oxygenation (ECMO) use, duration of hospitalization and survival in neonates with CDH was analyzed. Performance of MSA in prediction of postnatal outcomes was compared with LHR, O/E LHR, TFLV, and O/E TFLV.
RESULTS: There were significant differences in MSA values not only between the CDH group and the control group but also in CDH patients with different survival outcomes. MSA was inversely correlated with O/E LHR, O/E TFLV, and TFLV. MSA, LHR, O/E LHR, TFLV, and O/E TFLV could all be used to predict survival of CDH patients. In addition, the receiver operating characteristic (ROC) curve showed that the test performance of MSA was similar to that of TFLV, O/E TFLV, and O/E LHR, but superior to that of LHR. MSA was also correlated with PH, need for ECMO support, and duration of hospitalization.
CONCLUSIONS: MRI measurement of MSA can provide various prognostic information for prenatally diagnosed LCDH, in addition to postnatal survival. The test performance of MSA is similar to TFLV, O/E TFLV, and O/E LHR.
CONCLUSIONS: • Mediastinal shift angle (MSA) can be measured quickly and reproducibly on MRI images. • MSA could provide more prognostic information other than postnatal survival for LCDH with good test performance. • MSA should be incorporated into prenatal risk stratification for LCDH to improve planning of postnatal management.