Background: Chronic obstructive pulmonary disease (COPD) and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) pose global challenges, with oxygen saturation (SpO₂) levels crucial in evaluating mortality. This study explored the correlation between admission SpO₂ levels and all-cause hospital mortality in patients with AECOPD, assessing whether SpO₂ can serve as an independent risk factor for predicting in-hospital mortality in these patients.

Methods: This study involved 996 AECOPD patients sourced from the Medical Information Mart for Intensive Care (MIMIC) III database (version 1.3), with 134 fatalities. Patients were categorized into a death group (n=134) and a survival group (n=862). The average admission SpO₂ value was recorded for all 996 AECOPD patients. Subsequently, a generalized additive model (GAM) curve was employed to examine the association between admission SpO₂ levels and all-cause hospital mortality. Following this, Cox regression analysis and survival analysis were conducted to further investigate the link between admission SpO₂ and all-cause hospital mortality.

Results: The GAM curve demonstrated a non-linear, U-shaped relationship between admission SpO₂ and all-cause hospital mortality in AECOPD patients. The nadir of all-cause hospital mortality was associated with an SpO₂ of 89.5%. Notably, an SpO₂ of 89.5% served as the optimal cutoff for predicting all-cause hospital mortality. Cox regression analysis identified SpO₂ as a risk factor for all-cause hospital mortality in AECOPD patients. Patients with SpO₂ ≥89.5% exhibited independently lower death risk compared to those with SpO₂ <89.5% (hazard ratio: 0.52; 95% confidence interval: 0.37–0.74; P<0.001).

Conclusions: Admission SpO₂ level is an independent risk factor for predicting all-cause hospital mortality in AECOPD patients and can serve as a prognostic indicator. A U-shaped relationship was observed, with an admission SpO₂ level of 89.5% associated with the lowest mortality, suggesting an optimal range for improved prognosis.

Keywords: Chronic obstructive pulmonary disease (COPD); acute exacerbation stage; peripheral blood oxygen saturation (peripheral blood SpO₂); all-cause in-hospital mortality; Medical Information Mart for Intensive Care III database (MIMIC III database)

Background: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is an effective lung protection strategy that avoids ventilator-induced lung injury. However, appropriate respiratory settings for VV-ECMO are yet to be established. This study aimed to elucidate the effects of ventilation under VV-ECMO using a newly developed rat VV-ECMO model and analyzed gene expression profiles.

Methods: Rats were assigned to three groups of five rats each: spontaneous breathing, conventional-protective ventilation, and ultra-protective ventilation. The conventional protective and ultraprotective ventilation groups received volume-controlled ventilation at a frequency of 60 and 20 beats/min, with tidal volumes of 6 and 3 mL/kg, respectively. VV-ECMO was performed at a pump flow rate of 20–30 mL/kg/min. At 120 min post initiation of VV-ECMO, rats were euthanized, and their lungs were harvested. Changes in gene expression were assessed using microarray analysis.

Results: Gene expression profile analyses revealed lowest expression of inflammation/immune promotion, cytotoxicity, and cell proliferation related genes (Defa5, Prg2, Siglec8, Atf3, Rnd1, Ctsg, and Gc), and the highest expression of inflammation/immune suppression related genes (Pp2d1) in the spontaneous breathing group as compared to that in the other two mechanical ventilation groups.

Conclusions: The findings of this study demonstrated that spontaneous breathing was the least invasive respiratory setting under VV-ECMO. Further, mechanical ventilation may be associated with lung injury even at low ventilation frequency and tidal volume.

Keywords: Gene expression; extracorporeal membrane oxygenation (ECMO); lung; ventilation; rat

Background: Unplanned early rehospitalization (UER) is common among lung transplant recipients, but its incidence varies among lung transplant centers. This study aimed to analyze the incidence, causes and predictors of UER in a lung transplant center in China and to explore the impact of preoperative nutritional risk status, postoperative duration of mechanical ventilation (MV) and extracorporeal membrane oxygenation support in the intensive care unit on unplanned readmission in lung transplant patients.

Methods: This study was conducted in one of the largest lung transplant centers in China. We collected demographic and clinical data from lung transplant recipients who underwent transplantation and were discharged in 2022. Predictors of UER within 30 days after discharge were analyzed through a retrospective cohort study.

Results: A total of 99 patients were included in this study. The incidence of UER was 29.3%. The three most common reasons were chest distress with shortness of breath (38%), cough with expectoration (21%), and fever (21%). Multivariate analysis revealed that the postoperative MV duration [odds ratio (OR) =1.027; 95% confidence interval (CI): 1.008–1.046; P=0.004] and preoperative Nutrition Risk Screening 2002 (NRS-2002) score (OR =1.615; 95% CI: 1.189–2.194; P=0.002) were significant risk factors for UER.

Conclusions: Patients with higher preoperative NRS-2002 scores and longer postoperative MV duration had a greater risk of UER within 30 days after initial discharge. More research is needed to determine whether improving preoperative nutritional risk status and shortening the duration of MV can reduce UER in patients.

Keywords: Lung transplantation; rehospitalization; unplanned early rehospitalization (UER)

Background: Single-use flexible bronchoscopes (SUFBs) offer various advantages over reusable bronchoscopes (RBs) including portability and cost-effectiveness, and potentially reduced infection transmission. Our study aimed to review the performance of the Ambu^® aScope™ 5 Broncho suite in Cork University Hospital.

Methods: Following ethical approval, data was collected prospectively on procedures performed with the Ambu^® aScope™ 5 in Cork University Hospital. Data included patient demographics, procedure details (location, indication, SUFB size, procedures, complications), and user satisfaction and demographics.

Results: There were 98 procedures performed with the Ambu^® aScope™ 5, all in the endoscopy suite. There were 42 female patients (42.9%) and 56 male (57.1%). Various sized models were used—2.7/1.2 (n=3), 4.2/2.2 (n=4), 5/2.2 (n=60), 5.6/2.8 (n=31). Infection was the most common indication while others included malignancy, haemoptysis, sarcoidosis, and asthma. The most commonly performed procedure was airway inspection (n=98), while bronchoalveolar lavage (BAL) (n=84), brushings (n=3), endobronchial biopsies (n=5), transbronchial needle aspiration (TBNA) (n=1), and argon plasma coagulation (APC) (n=1) were among others. The average user satisfaction rating (from one to five in ascending order of satisfaction) was 4.8 [5 (n=85), 4 (n=9), 3 (n=1), 2 (n=3), 1 (n=0)]. The most common reason for user dissatisfaction was related to suction (n=3). Conversion from single-use to RB was not required in any case. There were no bronchoscope-related patient complications.

Conclusions: Within this cohort of patients, the Ambu^® aScope™ 5 was both safe and versatile with a high level of user satisfaction.

Keywords: Single-use flexible bronchoscope (SUFB); bronchoscopy; interventional pulmonology

Professor JIANXING HE, a leading scientist is recruiting postdoctoral candidates. His team pioneered on (1) tubeless minimally invasive techniques, including autonomous ventilation lung transplantation and tracheal reconstruction; (2) An intelligent screening, diagnosis, treatment, and rehabilitation system for lung cancer; (3) Heterotopic heart-lung combined transplantation. Prof. HE’s team has published a large number of internationally influential research achievements, encompassing significant innovations in lung cancer surgery, personalized treatment, and application of cutting-edge technologies. Their work has been featured in top-tier international scholarly journals such as NEJM and The Lancet, with a total of 678 SCI papers published. Among these, 36 papers’ IF＞30, and 72 papers’ IF＞10.