鈴木 拓児

In clinical clerkship (CC), medical students can practice evidence-based medicine (EBM) with their assigned patients. Although CC can be a valuable opportunity for EBM education, the impact of EBM training, including long-term behavioral changes, remains unclear. One hundred and nine fourth- and fifth-year medical students undergoing CC at a medical school in Japan attended a workplace-based learning program for EBM during CC (WB-EBM), which included the practice of the five steps of EBM. The program's effect on the students' attitudes toward EBM in CC was assessed through questionnaires. A total of 88 medical students participated in the program. Responses to the questionnaire indicated high satisfaction with the WB-EBM program. The most common theme in students' clinical problems with their assigned patients was the choice of treatment, followed by its effect. Based on the responses in the post-survey for the long-term effects of the program, the frequency of problem formulation and article reading tended to increase in the 'within six months' group comprising 18 students who participated in the WB-EBM program, compared with the control group comprising 34 students who did not. Additionally, the ability to self-assess problem formulation was significantly higher, compared with the control group. However, among 52 students who participated in the WB-EBM program more than six months later, EBM-related behavioral habits in CC and self-assessments of the five steps of EBM were not significantly different from those in the control group. The WB-EBM program was acceptable for medical students in CC. It motivated them to formulate clinical questions and enhanced their critical thinking. Moreover, the WB-EBM program can improve habits and self-evaluations about EBM. However, as its effects may not last more than six months, it may need to be repeated across departments throughout CC to change behavior in EBM practice.

Pulmonary hypertension (PH) is a devastating disease characterized by vascular remodeling, resulting in right ventricular failure and death. Dysregulation of energy metabolism is linked to PH pathogenesis. Trimetazidine (TMZ), a selective long-chain 3-ketoacyl coenzyme A thiolase inhibitor, is critical in maintaining energy metabolism. Despite the indicated TMZ's inhibitory effect on pulmonary vascular remodeling in PH development, the integrated evaluation of the changes in biomolecules, such as metabolites and transcripts, that TMZ induces in the lung and heart tissues is largely unknown in vivo. For an improved understanding of the molecular mechanism involving the effects of TMZ on PH development, we performed a comprehensive analysis of the changes in cardiac metabolites and pulmonary transcripts of SU5416-Hypoxia (Su/Hx) rats treated with TMZ. Metabolomic analysis of the Su/Hx-induced PH hearts demonstrated that TMZ reduced the long-chain fatty acid concentration. Additionally, TMZ alleviated PH degree and excessive strain on the right heart functions in rats with Su/Hx-induced PH. We identified the candidate target genes for TMZ treatment during PH development. Interestingly, the mRNA levels of the fatty acid transporters were substantially downregulated by TMZ administration in the lungs with Su/Hx-induced PH. Notably, TMZ suppressed excessive proliferation of human pulmonary artery smooth muscle cells under hypoxic conditions. Our study suggests that TMZ ameliorates PH development by involving energy metabolism in the lungs and heart.

BACKGROUND: Serum levels of stratifin (SFN), a member of the 14-3-3 protein family, increase in patients with drug-induced lung injury associated with diffuse alveolar damage. Therefore, we hypothesised that SFN levels would be higher in those experiencing acute exacerbation of interstitial lung disease (AE-ILD). A secondary analysis was also planned to determine whether SFN levels could discriminate survival in those with AE. METHODS: Thirty-two patients with clinically stable ILD (CS-ILD) and 22 patients with AE-ILD were examined to assess whether high serum SFN levels were associated with AE-ILD and whether SFN levels reflected disease severity or prognosis in patients with AE-ILD. RESULTS: Serum SFN levels were higher in the AE-ILD group than in the CS-ILD group (8.4 ± 7.6 vs. 1.3 ± 1.2 ng/mL, p < 0.001). The cut-off value of the serum SFN concentration for predicting 90-day and 1-year survival was 6.6 ng/mL. SFN levels were higher in patients who died within 90 days and 1 year than in patients who survived beyond these time points (13.5 ± 8.7 vs. 5.6 ± 5.3 ng/mL; p = 0.011 and 13.1 ± 7.5 vs. 3.1 ± 1.9 ng/mL; p < 0.001, respectively) in the AE-ILD group. When this cut-off value was used, the 90-day and 1-year survival rates were significantly better in the population below the cut-off value than in those above the cut-off value (p = 0.0017 vs. p < 0.0001). CONCLUSIONS: High serum SFN levels are associated with AE-ILD and can discriminate survival in patients with AE-ILD.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been used to diagnose and stage lung cancer. Acquire™ Pulmonary and Expect™ Pulmonary dedicated EBUS-TBNA needles were introduced as the Franseen and Lancet needles, respectively. It is still unclear whether the Franseen or Lancet needles yield a higher quality specimen especially focusing on next-generation sequencing-based molecular testing. METHODS: A single-center, prospective study performed at the Chiba University Hospital randomly assigned patients to two groups: Group A, wherein the first and second EBUS-TBNA were performed using Lancet and Franseen needles, respectively, and Group B, wherein the first and second EBUS-TBNA were performed using Franseen and Lancet needles, respectively. Each specimen was compared and analyzed pathologically. The primary outcome was the histological tissue area except blood clot and the cellularity of each sample. We also examined the success rate of molecular testing. RESULTS: Twelve patients who underwent EBUS-TBNA between November 2022 and February 2023 were enrolled in this study. The tissue area of the specimens obtained by the Franseen and Lancet needles was 13.3 ± 6.4 mm2 and 10.6 ± 6.3 mm2, respectively (P = .355). The tumor cellularity in the specimens obtained using the Franseen and Lancet needles was 54.0 ± 30.3 and 46.2 ± 36.3%, respectively (P = .608). The success rate of molecular testing using the single-pass sample by Franseen needle was 85.7 and 57.1% by Lancet needle. No serious complications were reported. CONCLUSIONS: The Franseen needle tended to show a greater amount of specimen with higher tumor cellularity than the Lancet needle which may contribute higher success rate of molecular testing. Further studies must be conducted to validate the results of this study. KEY FINDINGS: What is known and what is new?  What is the implication, and what should change now?

Numerous SARS-CoV-2 variant strains with altered characteristics have emerged since the onset of the COVID-19 pandemic. Remdesivir (RDV), a ribonucleotide analogue inhibitor of viral RNA polymerase, has become a valuable therapeutic agent. However, immunosuppressed hosts may respond inadequately to RDV and develop chronic persistent infections. A patient with respiratory failure caused by interstitial pneumonia, who had undergone transplantation of the left lung, developed COVID-19 caused by Omicron BA.5 strain with persistent chronic viral shedding, showing viral fusogenicity. Genome-wide sequencing analyses revealed the occurrence of several viral mutations after RDV treatment, followed by dynamic changes in the viral populations. The C799F mutation in nsp12 was found to play a pivotal role in conferring RDV resistance, preventing RDV-triphosphate from entering the active site of RNA-dependent RNA polymerase. The occurrence of diverse mutations is a characteristic of SARS-CoV-2, which mutates frequently. Herein, we describe the clinical case of an immunosuppressed host in whom inadequate treatment resulted in highly diverse SARS-CoV-2 mutations that threatened the patient's health due to the development of drug-resistant variants.

Two anti-fibrotic drugs, pirfenidone (PFD) and nintedanib (NTD), are currently used to treat idiopathic pulmonary fibrosis (IPF). Peripheral blood mononuclear cells (PBMCs) are immunocompetent cells that could orchestrate cell–cell interactions associated with IPF pathogenesis. We employed RNA sequencing to examine the transcriptome signature in the bulk PBMCs of patients with IPF and the effects of anti-fibrotic drugs on these signatures. Differentially expressed genes (DEGs) between “patients with IPF and healthy controls” and “before and after anti-fibrotic treatment” were analyzed. Enrichment analysis suggested that fatty acid elongation interferes with TGF-β/Smad signaling and the production of oxidative stress since treatment with NTD upregulates the fatty acid elongation enzymes ELOVL6. Treatment with PFD downregulates COL1A1, which produces wound-healing collagens because activated monocyte-derived macrophages participate in the production of collagen, type I, and alpha 1 during tissue damage. Plasminogen activator inhibitor-1 (PAI-1) regulates wound healing by inhibiting plasmin-mediated matrix metalloproteinase activation, and the inhibition of PAI-1 activity attenuates lung fibrosis. DEG analysis suggested that both the PFD and NTD upregulate SERPINE1, which regulates PAI-1 activity. This study embraces a novel approach by using RNA sequencing to examine PBMCs in IPF, potentially revealing systemic biomarkers or pathways that could be targeted for therapy.

BACKGROUND Hemoptysis due to airway hemorrhage is treated with hemostatic agents, bronchial artery embolization (BAE), or surgical resection. We present the case of a 65-year-old man with refractory hemoptysis associated with chronic progressive pulmonary aspergillosis (CPPA) who failed to respond to combined endobronchial occlusion (EBO) with endobronchial Watanabe spigot (EWS) and BAE. CASE REPORT A 63-year-old man was diagnosed with CPPA in the right upper lung and presented to our hospital 2 years later for hemoptysis at age 65. He developed severe hemoptysis during an outpatient visit, and was urgently admitted, intubated, and ventilated to prevent choking on blood clots. Chest computed tomography showed a large mass in the apical portion of the right lung, constituting apical pleural thickening and an encapsulated pleural effusion, and dilatation in the bronchial artery supplying the right upper lung lobe. Bronchoscopy revealed the right upper lobe B1-B3 as the bleeding source. The patient had recurrent hemoptysis that was not controlled by BAE or 6 EBO+EWS procedures, and he ultimately died of hypoxemia.In the literature review, EBO+EWS can effectively control hemoptysis in appropriate cases, without the need for BAE or surgical lung resection. It is less invasive, is associated with fewer adverse events than BAE or surgery, and can achieve temporary hemostasis for severe hemoptysis. CONCLUSIONS BAE and EBO+EWS were ineffective in controlling recurrent hemoptysis caused by CPPA in this case. However, a multidisciplinary approach such as attempting hemostasis with combined EBO+EWS and BAE may be a viable treatment option in severe cases of hemoptysis.

Acute respiratory distress syndrome (ARDS) is characterized by dysregulated inflammation and increased permeability of lung microvascular cells. CD26/Dipeptidyl peptidase-4 (DPP4) is a type II membrane protein that is expressed in several cell types and mediates multiple pleiotropic effects. We previously reported that DPP4 inhibition by sitagliptin attenuates lipopolysaccharide (LPS)-induced lung injury in mice. The current study characterized the functional role of CD26/DPP4 expression in LPS-induced lung injury in mice, isolated alveolar macrophages, and cultured lung endothelial cells. In LPS-induced lung injury, inflammatory responses (bronchoalveolar lavage fluid (BALF) neutrophil numbers and several pro-inflammatory cytokine levels) were attenuated in Dpp4 knockout (Dpp4 KO) mice. However, multiple assays of alveolar capillary permeability were similar between the Dpp4 KO and wild-type mice. TNF-α and IL-6 production was suppressed in alveolar macrophages isolated from Dpp4 KO mice. In contrast, in cultured mouse lung microvascular endothelial cells (MLMVECs), reduction in CD26/DPP4 expression by siRNA resulted in greater ICAM-1 and IL-6 expression after LPS stimulation. Moreover, the LPS-induced vascular monolayer permeability in vitro was higher in MLMVECs treated with Dpp4 siRNA, suggesting that CD26/DPP4 plays a protective role in endothelial barrier function. In summary, this study demonstrated that genetic deficiency of Dpp4 attenuates inflammatory responses but not permeability in LPS-induced lung injury in mice, potentially through differential functional roles of CD26/DPP4 expression in resident cellular components of the lung. CD26/DPP4 may be a potential therapeutic target for ARDS and warrants further exploration to precisely identify the multiple functional effects of CD26/DPP4 in ARDS pathophysiology.

BACKGROUND: The usefulness of lung ultrasound (LUS) has been demonstrated. However, it is unclear whether diagnostic techniques using LUS are accepted by all physicians. A simple simulation-based educational program may improve the LUS skills of beginners, but it has not been fully assessed. OBJECTIVE: This prospective study was conducted to assess the educational outcomes of LUS training using a high-fidelity simulator. METHODS: A simulator-based program for LUS was conducted. All clerkship students at the Department of Respirology at Chiba University Hospital participated in the program from December 2022 to April 2023. The participants watched a 30 minute teaching video on demand before a hands-on session lasting for 1 hour during the first week of the clinical clerkship. The readiness of the participants to learn LUS and the usefulness of the program were assessed using questionnaires administered before and after the program. The LUS skills were assessed using simulator-based tests during Weeks 1 and 4. Data on the accuracy and time required to answer the questions were collected during the tests. RESULTS: Forty clerkship students participated in this study. Thirty-three (82.5%) had received other ultrasound education; however, only two (5.0%) had experience with LUS. Based on the questionnaire responses, the participants perceived LUS as useful (preprogram: 4.6 vs. postprogram: 4.8; P = 0.010; a 5-point Likert scale was used [1: not useful to 5: useful]). The simulator-based tests showed comparable accuracies at Weeks 1 and 4 for pneumothorax (Week 1: 47.5% vs. Week 4: 52.5%; P = 0.623), pulmonary edema (Week 1: 100% vs. Week 4: 100%; P = 1.000), and pleural effusion (Week 1: 37.5% vs. Week 4: 40.0%; P = 0.800). The time required for scanning was the same for each question. In addition, the test results did not differ with prior learning, previous knowledge, or experience during clinical clerkships on LUS. CONCLUSION: A short educational program consisting of on-demand learning and hands-on sessions with a high-fidelity simulator would be effective in equipping clerkship students with basic LUS skills. However, to increase its educational effectiveness to a practical degree, the program should be improved, and more opportunities for training using simulators should be provided.

BACKGROUND: Pulmonary arterial hypertension is a serious medical condition. However, the condition is often misdiagnosed or a rather long delay occurs from symptom onset to diagnosis, associated with decreased 5-year survival. In this study, we developed and tested a deep-learning algorithm to detect pulmonary arterial hypertension using chest X-ray (CXR) images. METHODS: From the image archive of Chiba University Hospital, 259 CXR images from 145 patients with pulmonary arterial hypertension and 260 CXR images from 260 control patients were identified; of which 418 were used for training and 101 were used for testing. Using the testing dataset for each image, the algorithm outputted a numerical value from 0 to 1 (the probability of the pulmonary arterial hypertension score). The training process employed a binary cross-entropy loss function with stochastic gradient descent optimization (learning rate parameter, α = 0.01). In addition, using the same testing dataset, the algorithm's ability to identify pulmonary arterial hypertension was compared with that of experienced doctors. RESULTS: The area under the curve (AUC) of the receiver operating characteristic curve for the detection ability of the algorithm was 0.988. Using an AUC threshold of 0.69, the sensitivity and specificity of the algorithm were 0.933 and 0.982, respectively. The AUC of the algorithm's detection ability was superior to that of the doctors. CONCLUSION: The CXR image-derived deep-learning algorithm had superior pulmonary arterial hypertension detection capability compared with that of experienced doctors.

Radiation-induced organizing pneumonia is a rare complication of radiation therapy for thoracic cancer. Carbon-ion radiotherapy, an emerging treatment modality for early-stage lung cancer treatment, can also cause lung injuries. However, as cases of radiation-induced organizing pneumonia caused by carbon-ion radiotherapy for lung cancer have not been reported, its clinical features remain unclear. A 69-year-old woman was referred to our hospital 11 months after being diagnosed with early lung cancer due to refractory pneumonitis induced by carbon-ion radiotherapy. She had developed fever and dyspnea 4 months after undergoing carbon-ion radiotherapy and was subsequently diagnosed with radiation pneumonitis. The administration of oral prednisolone resulted in improvement. However, she relapsed each time the dose of prednisolone was tapered. She was diagnosed with radiation-induced organizing pneumonia caused by carbon-ion radiotherapy for lung cancer based on the clinical course and the results of the examination performed at our hospital. An improvement was observed after administering methylprednisolone (1000 mg/d) for 3 days. The dose of oral prednisolone was slowly tapered over a period of ≥6 months with no relapse. Organizing pneumonia caused by carbon-ion radiotherapy for lung cancer is treatable with corticosteroids; however, tapering the dose of corticosteroids may lead to relapse.

BACKGROUND Immunoglobulin A (IgA) vasculitis is a systemic vasculitis that involves the small vessels. It is mainly characterized by skin symptoms such as purpura, arthritis/arthralgia, abdominal symptoms, and nephropathy, which are caused by IgA adherence to the vessel walls. Herein, we report the case of an advanced non-small cell lung cancer (NSCLC) and a purpuric skin rash of the legs that developed during fourth-line chemotherapy with tegafur/gimeracil/oteracil (S-1). CASE REPORT A 68-year-old man diagnosed with NSCLC 2 years ago was undergoing S-1 as fourth-line chemotherapy when he developed purpura and edema on the lower extremities. Biopsy renal specimens were consistent with IgA vasculitis. Considering his medical history, both IgA vasculitis induced by S-1 and a paraneoplastic syndrome were considered, although the exact cause could not be identified. Subsequently, chemotherapy was discontinued because of his deteriorating general condition, and he received optimal supportive care. The purpura spontaneously disappeared; however, his ascites and renal function deteriorated. Systemic steroids improved renal function, but the ascites did not resolve. One month after being diagnosed with IgA vasculitis, the patient died due to deterioration of his general condition. CONCLUSIONS This case emphasizes the occurrence of IgA vasculitis during lung cancer treatment and its potential impact on the disease course of lung cancer. Moreover, the possible causes of IgA vasculitis in this case were paraneoplastic syndrome or S-1 adverse effects, but further case series are needed to gain a more comprehensive understanding. Refractory, steroid-unresponsive ascites may occur as an abdominal manifestation of IgA vasculitis.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disease that often causes progressive pulmonary fibrosis (HPS-PPF) in some genetic types with high mortality rates. No effective treatment for HPS-PPF other than lung transplantation has been established. Herein, we report a case of HPS type 1 with progressive pulmonary fibrosis treated with long-term nintedanib administration followed by lung transplantation. The resected lungs revealed diffuse interstitial lung lesions, including fibroblastic foci, suggesting the potential beneficial effects of anti-fibrotic drugs in HPS-PPF. Together with previous reports, the present case suggests that nintedanib might be a safe and effective drug for HPS-PPF.

Solid organ transplant (SOT) recipients with coronavirus disease-2019 (COVID-19) experience prolonged viral shedding, and they are forced to stay in the hospital because of the requirement for COVID-19 isolation. Here, we present two cases (lung and renal transplant recipients), wherein the isolation period was shortened by reducing the dosage of mycophenolate mofetil (MMF). Both patients recovered well from COVID-19 pneumonia. This case study suggests that a reduction in MMF dosage may lead to a shorter hospitalization period in SOT recipients with COVID-19.

Pneumonia caused by Legionella longbeachae, transmitted through contaminated soil, is very rare in Japan. A 70-year-old man with severe respiratory failure was admitted to our hospital and underwent multidisciplinary procedures. Although a urinary antigen test was negative for Legionella, he was clinically diagnosed with legionellosis and administered levofloxacin. His condition subsequently improved. Thereafter, sputum culture detected L. longbeachae. Because the DNA of L. longbeachae was detected in the gardening soil, it is suspected source of infection. Therefore, it is important to suspect legionellosis based on clinical information, even if a urine antigen test is negative.

A 51-year-old Thai woman diagnosed with β-thalassemia underwent regular blood transfusion and iron-chelating therapy. However, after voluntarily discontinuing treatment, the patient developed progressive dyspnea and was diagnosed with pulmonary hypertension following right heart catheterization. Despite resuming blood transfusions, her condition did not improve. Because the patient had a history of multiple organ failure, curative treatment for β-thalassemia was not feasible, and macitentan was administered. Despite experiencing hypotension as an adverse event, her condition remained stable during macitentan treatment. Thus, macitentan may be well tolerated in patients with pulmonary hypertension caused by β-thalassemia with multiple organ dysfunction.

Pleuroparenchymal fibroelastosis (PPFE) progresses slowly but sometimes relatively quickly, leading to decreased activities of daily living (ADL) and muscle weakness. Skeletal muscle atrophy and muscle weakness in chronic obstructive pulmonary disease (COPD) patients may be caused by cachexia and are associated with reduced ADLs and increased risk of death. However, the association between skeletal muscle mass and the prognosis of PPFE patients remains unknown. We retrospectively analysed the clinical significance of the cross-sectional area of the erector spinae muscle (ESMCSA), a skeletal muscle index, and predictors of mortality within 3 years in PPFE 51 patients, idiopathic pulmonary fibrosis (IPF) 52 patients and COPD 62 patients. PPFE patients had significantly lower ESMCSA than IPF or COPD patients, and lower ESMCSA (< 22.57 cm2) was associated with prognosis within 3 years (log-rank test; p = 0.006), whereas lower body mass index (BMI) showed no association. Multivariate analysis showed that ESMCSA was an independent predictor of mortality within 3 years in PPFE patients (hazard ratio, 0.854; 95% confidence interval: 0.737-0.990, p = 0.036). These results suggest the importance of monitoring ESMCSA in PPFE patients and that assessing ESMCSA in PPFE patients could be a more useful prognostic indicator than BMI.

Although intrathoracic extramedullary haematopoiesis (EMH) is rare, its nodular lesions should be differentiated from malignancy. 111In-bone marrow scintigraphy can be useful for the non-invasive diagnosis of intrathoracic EMH because extramedullary accumulation of 111In can be determined as EMH.

Objective Venous thromboembolism (VTE) is a common complication of severe coronavirus disease 2019 (COVID-19) and is associated with its prognosis. The fibrin monomer complex (FMC), a marker of thrombin generation, is reportedly useful in diagnosing acute thrombosis. To date, there has been only one report on FMC in COVID-19, and the usefulness of FMC in COVID-19 is unknown. We therefore evaluated the frequency of VTE in non-intensive-care unit COVID-19 patients in Japan and determine the clinical utility of FMC in COVID-19. Methods This was a single-center retrospective study. Laboratory test results and outcomes (thrombosis and severe progression of COVID-19) were obtained via medical record review. We assessed the relationship between FMC and VTE incidence and evaluated the association between elevated FMC levels and severe progression of COVID-19. Patients/Materials This study included 247 patients with COVID-19 who were hospitalized between December 2020 and September 2021 and had had their levels of D-dimer and FMC measured. Results Of the 247 included patients, 3 (1.2%) developed VTE. All three had elevated FMC levels on admission; however, the D-dimer level was not elevated in one case on admission. The FMC level was significantly higher in the group with severe COVID-19 progression than in the group without severe progression. A multivariate analysis showed that severe progression was associated with elevated FMC levels (odds ratio, 7.40; 95% confidence interval, 2.63-22.98; p<0.001). Conclusion FMC can be useful for diagnosing VTE in the acute phase of COVID-19. Elevated FMC was found to be associated with severity on admission and severe progression.

The percentage cross-sectional area of the lung under five (%CSA<5) is the percentage of pulmonary vessels with <5 mm2 area relative to the total lung area on computed tomography (CT). The extent that %CSA<5 is related to pulmonary hemodynamics in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is unclear, as is the effect of pulmonary endarterectomy (PEA) on %CSA<5. Therefore, we aimed to evaluate the clinical significance of %CSA<5 in patients with CTEPH. We studied 98 patients (64 females, mean age 62.5 ± 11.9 years), who underwent CT with %CSA<5 measurement and right heart catheterization (RHC). Patients were classified into groups based on eligibility for PEA. We compared the %CSA<5 with pulmonary hemodynamics measured by RHC in various groups. In 38 patients who underwent PEA, the relationship between %CSA<5 and pulmonary hemodynamics was also evaluated before and after PEA. Significant correlations between %CSA<5 and pulmonary vascular resistance, and compliance, and pulmonary artery pulse pressure were observed in all patients. Pulmonary hemodynamics in the patients who underwent or were eligible for PEA showed a significant correlation with %CSA<5. Additionally, %CSA<5 was significantly lower in the postoperative than in the preoperative group. There was no correlation between changes in %CSA<5 and pulmonary hemodynamics before and after PEA. Furthermore, %CSA<5 did not correlate significantly with prognosis. %CSA<5 may reflect pulmonary hemodynamics in CTEPH with central thrombosis. Furthermore, %CSA<5 was reduced by PEA postoperatively. However, %CSA<5 is not a prognostic indicator, its clinical usefulness in CTEPH patients is limited, and further validation is required.

This study investigated the effects of partially hydrolyzed guar gum (PHGG) on the development of pulmonary arterial hypertension using a SU5416/hypoxia rat model. Our results demonstrated that PHGG treatment suppressed the development of pulmonary hypertension and vascular remodeling with an altered gut microbiota composition.

INTRODUCTION: Secondary spontaneous pneumothorax (SSP) occurs as one of the complications associated with interstitial pneumonia (IP). Chest drainage is performed when there is a large volume of air in the pleural space. Notably, SSP with IP (SSP-IP) is frequently not curable by chest drainage only. A digital drainage system (DDS) provides an objective evaluation of air leakage and maintains a pre-determined negative pressure, compared to an analog drainage system (ADS). Few studies have reported the effectiveness of DDS in the treatment of SSP-IP. This study aimed to assess the usefulness of DDS for SSP-IP. METHODS: This retrospective study included patients with SSP-IP who had undergone chest drainage. We reviewed the included patients' medical records, laboratory data, computed tomography findings, and pulmonary function data. RESULTS: DDS was used in 24 patients and ADS in 49 patients. The mean duration of chest drainage was 11.4 ± 1.9 days in the DDS group and 14.2 ± 1.3 days in the ADS group, which was not significantly different (p = 0.218). Surgery, pleurodesis, and/or factor XIII administration were performed in 40 patients. Additionally, five (20.8%) patients in the DDS group and nine (18.4%) in the ADS group had a recurrence of pneumothorax within 4 weeks (p = 1.000). One patient (14%) in the DDS group and six (12.2%) in the ADS group (p = 0.414) were cured of pneumothorax but later died. CONCLUSION: DDS did not demonstrate a significant difference in the shortening of chest drainage duration. Further study is needed to validate the results of this study.