Objective:To evaluate the efficacy and safety of utilizing bicarbonate derived from the metabolism of regional citrate anticoagulation (RCA) as the sole base source for replacement fluid in continuous veno-venous hemofiltration (CVVH).Methods:A retrospective analysis was conducted on ICU patients who underwent RCA combined with CVVH between July 2024 and February 2025, with pre-treatment serum bicarbonate levels ranging from 18 mmol/L to 27 mmol/L. Patients managed with the "traditional RCA protocol" (4% citrate initially set at 1.2–1.5 times blood flow rate), using commercial calcium-containing replacement fluid (4 L/bag) with additional sodium bicarbonate supplementation, were assigned to the control group. Those treated with the "fixed RCA protocol" (targeting an extracorporeal citrate concentration of approximately 4 mmol/L), with a total effluent-to-citrate flow ratio of 9–10:1 and no supplemental sodium bicarbonate, were assigned to the study group. Outcomes included the incidence of metabolic acid-base disorders, amount of sodium bicarbonate used, filter lifespan, adverse events (e.g., bleeding), and 28-day mortality.Results:A total of 86 patients were enrolled, with 42 in the control group and 44 in the study group. The incidence of metabolic alkalosis was significantly higher in the control group (30.9%) than in the study group (2.3%) ( P < 0.001), while no significant difference was observed in the incidence of metabolic acidosis. Three patients in the study group received additional sodium bicarbonate during CVVH. The median sodium bicarbonate usage in the study group was 0 (0–5.6) mL, significantly lower than that in the control group [15.3 ( 8.3–24.3)] mL, P = 0.002). Filter lifespan was significantly shorter in the control group (36.4 ± 19.2 hours) compared to the study group (51.2 ± 17.6) h; P < 0.001]. Post-filter ionized calcium was significantly higher in the control group [(0.39 ± 0.08) mmol/L) than in the study group [(0.32 ± 0.09) mmol/L; P < 0.001]. CVVH was discontinued due to filter clotting in 71.4% of control patients, compared to 36.4% in the study group ( P < 0.05). In contrast, 45.5% of study group patients discontinued CVVH due to meeting treatment goals, versus only 9.5% in the control group ( P < 0.05). No treatment-related bleeding or citrate accumulation events occurred in either group. The 28-day mortality was 28.6% in the control group and 29.5% in the study group, with no statistically significant difference. Conclusions:In relatively stable patients, RCA can serve as a safe and effective independent base source for CVVH replacement fluid. This approach not only ensures adequate anticoagulation but also significantly reduces the incidence of metabolic alkalosis.

Objective:To explore the potential advantages and application prospects of cardiopulmonary resuscitation ventilation mode (CPRV) for ventilation during CPR, through comparing of the resuscitation effect of CPRV, intermittent positive pressure ventilation (IPPV) and impedance threshold device (ITD) during advanced cardiovascular life support (ACLS).Methods:30 miniature landrace pigs [weighing (31.7±4.5) kg] were randomly divided into three groups: CPRV group, IPPV group and ITD group (10 pigs in each group). Each animal received 5 min of chest compressions only CPR after 3 min of untreated ventricular fibrillation. Then in the ACLS stage, chest compressions and mechanical ventilation (tidal volume of 7 mL/kg, respiratory rate 10 times/min) were performed according to the divided groups. Defibrillation was delivered after 16 min of ACLS, and intravenous epinephrine was administered for the pigs without return of spontaneous circulation (ROSC). A second defibrillation was delivered after 2 more minutes of CPR. Blood gases, respiratory parameters, and hemodynamic parameters were collected at baseline, ACLS 8 min and ACLS 16 min. ROSC after defibrillation was also recorded.Results:At ACLS 8 min and 16 min, intrathoracic high pressure and intrathoracic pressure variability of CPRV group were significantly higher than those of IPPV and ITD group, while the absolute value of intrathoracic negative pressure in CPRV group was higher than that in IPPV group (all P <0.01), but no difference was found between CPRV group and ITD group. The levels of arterial pH, PaO 2 and venous oxygen saturation in CPRV group were significantly higher than those in IPPV group and ITD group during ACLS, while PaCO 2 was significantly lower in CPRV group than in IPPV group and ITD group (all P <0.05). Aortic blood pressure, coronary perfusion pressure and carotid blood flow during ACLS in CPRV group were significantly higher than those in IPPV group, and right atrial pressure of CPRV group was significantly lower than that of IPPV group (all P <0.05). Coronary perfusion pressure of CPRV group was significantly higher than that of ITD group at ACLS 16 min but not ACLS 8 min, and there were no differences of aortic blood pressure and carotid blood flow between CPRV group and ITD group. The total ROSC rate in the CPRV group (90%) was significantly higher than that in the IPPV group (30%) and the ITD group (40%) (P <0.05). Conclusion:Ventilation with CPRV during ACLS showed better ventilation, oxygenation, hemodynamic effects and higher ROSC than IPPV and ITD, and the use of CPRV during CPR shows a certain application prospect.

Objective:To observe the clinical effect of Shenfu injection in preventing septic cardiomyopathy (SIC) in septic patients.Methods:From June 2022 to January 2023, patients with sepsis or septic shock who did not develop SIC were randomly divided into treatment group and control group according to the ratio of 1:1. In the treatment group, Shenfu injection (50 mL) was pumped intravenously once every 12 hours for 5 days. In the control group, 50 mL of normal saline was pumped intravenously once every 12 hours, and the course of treatment was 5 days. The primary end point was the incidence of SIC in the first 5 days. The secondary end points were the application time of vasoactive drugs, fluid balance in the previous week, hospitalization time in ICU, total ventilation time and 28-day mortality.Results:112 patients were randomly divided into two groups. Seven patients in the treatment group were excluded twice, and finally 49 patients were included in the analysis, while six patients in the control group were excluded twice and 50 patients included in the analysis. The total incidence of SIC in the treatment group within 5 days was significantly lower than that in the control group (42.9% vs. 64.0%, P = 0.035). Among them, the left ventricular systolic dysfunction in the treatment group was significantly lower than that in the control group (24.5% vs 52.0%, P=0.005), and there was no significant difference in the incidence of left ventricular diastolic dysfunction between the two groups. The incidence of right ventricular dysfunction in the control group was 28.0%, which was significantly higher than 10.2% in the treatment group ( P = 0.025). The duration of using vasoconstrictors in the treatment group was 75(48, 97) hours, which was significantly lower than 97(66, 28) hours in the control group ( P = 0.039). The duration of inotropic drugs use in the treatment group was 32(18, 49) h, which was also significantly shorter than 44(25, 61) h in the control group ( P=0.046). The fluid balance of the control group in the first week was (1 260±850) mL, which was significantly higher than (450±520) mL in the treatment group ( P=0.008). There was no statistical difference in ICU stay, total ventilation time and 28-day mortality between the two groups (all P > 0.05). Conclusion:Early application of Shenfu injection can significantly reduce the incidence of SIC, accompanied by less use of vasoactive drugs and positive fluid balance, which has a good clinical application prospect.

Objective:To investigate the value of early tight junction protein Claudin-5 levels in predicting the severity of acute pancreatitis (AP).Methods:A prospective observational study was conducted, including patients diagnosed with AP and admitted to the Northern Jiangsu People's Hospital from December 1, 2021 to November 30, 2022. Eligible healthy volunteers were randomly selected to serve as healthy controls during the same period. Patients were classified into mild acute pancreatitis (MAP) group, moderate-severe acute pancreatitis (MSAP) group, and severe acute pancreatitis (SAP) group based on the 2012 Atlanta classification criteria. Patients with SAP were then divided into three subgroups of 1, 3, and 7 days based on the duration of hospitalization. Baseline data, such as gender, age, underlying disease, and probable etiology, was collected from all enrolled individuals. The enzyme-linked immunosorbent assay (ELISA) was employed to detect serum Claudin-5 levels in each cohort of enrollees. Data on additional serologic indicators, including hematocrit (HCT), albumin (Alb), serum Ca 2+, C-reactive protein (CRP), and procalcitonin (PCT) levels, were obtained via the in-hospital test query system in each group of patients with AP. The modified Marshall score (mMarshall), modified CT severity index (mCTSI) score, bedside severity index of severity in acute pancreatitis (BISAP) score, and acute physiology and chronic health evaluation Ⅱ(APACHEⅡ) were recorded for each group of patients with AP. Differences in the above indicators between groups were analyzed and compared. Spearman's correlation method was employed to examine the relationship between Claudin-5 levels and each influential factor. The receiver operator characteristic curve (ROC curve) was plotted to analyze the predictive value of each influencing factor on SAP. Ridge regression was used to screen for independent risk factors for SAP. Results:A total of 109 patients with AP were enrolled, comprising 66 in the MAP group, 15 in the MSAP group, and 28 in the SAP group. Additionally, 27 healthy volunteers were enrolled as the healthy control group. No statistically significant differences were observed in gender and age among the enrolled groups, and no statistically significant differences were identified among the three groups of patients with AP in terms of underlying disease and etiologic composition. As the disease progressed, serum Claudin-5 levels exhibited a notable increase across all AP patient groups, and they were all significantly higher than those in the healthy control group [ng/L: 888.58 (574.52, 1 141.59), 3 749.02 (2 784.93, 5 789.92), 4 667.81 (3 935.21, 7 315.66) vs. 291.13 (250.19, 314.75), all P < 0.05]. Subgroup analyses showed that as the disease duration prolonged, patients in the SAP group exhibited a notable decline in Claudin-5 levels at 3 days post-admission, compared with those at 1 day post-admission [ng/L: 2 052.59 (1 089.43, 4 006.47) vs. 4 667.81 (3 935.21, 7 315.66), P < 0.05]. Spearman correlation analysis showed that serum Claudin-5 levels in patients with AP were significantly positively correlated with CRP, PCT, HCT, and mMarshall, mCTSI, and BISAP scores ( r values were 0.570, 0.525, 0.323, 0.774, 0.670, 0.652, all P < 0.001), and significantly negatively correlated with Alb ( r = -0.394, P < 0.001). A significant trend was observed in patients with AP, with an increase of HCT levels and a decrease of Alb levels as the disease progressed (both P < 0.05). An improvement of aforementioned phenomena was observed in patients with SAP following treatment, indirectly indicating that serum Claudin-5 level was a positive indicator of vascular leakage. ROC curve analysis showed that serum Claudin-5 levels in patients with AP exhibited the highest accuracy for early prediction of SAP, with the area under the ROC curve (AUC) of 0.948. When serum Claudin-5 levels ≥2 997 ng/L, the sensitivity for early screening for SAP was 100% and the specificity was 88.89%. Multifactorial ridge regression analysis showed that serum Claudin-5 level, PCT and APACHEⅡscore could be used as independent risk factors for early prediction of SAP (all P < 0.05). Conclusion:Serum Claudin-5 levels facilitate early prediction of SAP and are strongly associated with inflammatory response and vascular leakage.

Objective:To compare the efficacy of high-flow nasal cannula oxygen therapy (HFNC) and non-invasive ventilation (NIV) in the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with moderate typeⅡ respiratory failure, to clarify the feasibility of HFNC in the treatment of AECOPD, and to explore the influencing factors of HFNC failure.Methods:This study was a randomized controlled trial of non-inferiority. Patients with AECOPD with moderate type Ⅱ respiratory failure [arterial blood gas pH 7.25-7.35, partial pressure of arterial blood carbon dioxide (PaCO 2)> 50 mmHg] admitted to the Intensive Care Unit (ICU) from January 2018 to December 2021 were randomly assigned to the HFNC group and NIV group to receive respiratory support. The primary endpoint was the treatment failure rate. The secondary endpoints were blood gas analysis and vital signs at 1 h, 12 h, and 48 h, total duration of respiratory support, 28-day mortality, comfort score, ICU length of stay, and total length of stay. Multivariate logistic regression analysis was used to evaluate the failure factors of HFNC treatment. Results:Totally 228 patients were randomly divided into two groups, 108 patients in the HFNC group and 110 patients in the NIV group. The treatment failure rate was 29.6% in the HFNC group and 25.5% in the NIV group. The risk difference of failure rate between the two groups was 4.18% (95% CI: -8.27%~16.48%, P=0.490), which was lower than the non-inferiority value of 9%. The most common causes of failure in the HFNC group were carbon dioxide retention and aggravation of respiratory distress, and the most common causes of failure in the NIV group were treatment intolerance and aggravation of respiratory distress. Treatment intolerance in the HFNC group was significantly lower than that in the NIV group (-29.02%, 95% CI -49.52%~-7.49%; P=0.004). After 1 h of treatment, the pH in both groups increased significantly, PaCO 2 decreased significantly and the oxygenation index increased significantly compared with baseline (all P < 0.05). PaCO 2 in both groups decreased gradually at 1 h, 12 h and 48 h after treatment, and the pH gradually increased. The average number of daily airway care interventions and the incidence of nasal and facial lesions in the HFNC group were significantly lower than those in the NIV group ( P < 0.05), while the comfort score in the HFNC group was significantly higher than that in the NIV group ( P=0.021). There was no significant difference between the two groups in the total duration of respiratory support, dyspnea score, ICU length of stay, total length of stay and 28-day mortality (all P > 0.05). Multivariate logistic regression analysis showed that acute physiology and chronic health evaluation Ⅱ score (≥15), family NIV, history of cerebrovascular accident, PaCO 2 (≥60 mmHg) and respiratory rate (≥32 times/min) at 1 h were independent predictors of HFNC failure. Conclusions:HFNC is not inferior to NIV in the treatment of AECOPD complicated with moderate type Ⅱ respiratory failure. HFNC is an ideal choice of respiratory support for patients with NIV intolerance, but clinical application should pay attention to the influencing factors of its treatment failure.

Objective:To compare the therapeutic effects of nasal high-flow oxygen therapy (HFNC) and nasal canal oxygenation (NCO) during breaks off non-invasive ventilation (NIV) for acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and to explore the feasibility of NIV combined with HFNC in the treatment of AECOPD.Methods:From August 2017 to July 2019, AECOPD patients with type Ⅱrespiratory failure (arterial blood gas pH <7.35, PaCO 2 > 50 mmHg) who were treated with NIV were randomly (random number) assigned to the HFNC group and NCO group at 1:1. The HFNC group received HFNC treatment during breaks from NIV and the NCO group received low-flow NCO during the NIV interval. The primary endpoint was the total respiratory support time. The secondary endpoints were endotracheal intubation, duration of NIV treatment and breaks from NIV, length of ICU stay, total length of hospital stay and so on. Results:Eighty-two patients were randomly assigned to the HFNC group and the NCO group. After secondary exclusion, 36 patients in the HFNC group and 37 patients in the NCO group were included in the analysis. The total respiratory support time in the HFNC group was significantly shorter than that in the NCO group [(74 ± 18) h vs. (93 ± 20) h, P = 0.042]. The total duration of NIV treatment in the HFNC group was significantly shorter than that in the NCO group [(36 ± 11) h vs. (51 ± 13) h, P=0.014]. There was no significant difference of the mean duration of single break from NIV between the two groups, but durations of break from NIV in the HFNC group were significantly longer than those in the NCO group since the third break from NIV ( P < 0.05). The intubation rates of the HFNC and NCO groups were 13.9% and 18.9%, respectively, with no significant difference ( P=0.562). The length of ICU stay in the HFNC group was (4.3 ± 1.7) days, which was shorter than that in the NCO group [(5.8 ± 2.1) days, P=0.045], but there was no significant difference in the total length of hospital stay between the two groups. Heart rate, respiratory rate, percutaneous carbon dioxide partial pressure and dyspnea score during the breaks from NIV in the NCO group were significantly higher than those in the HFNC group, and the comfort score was lower than that in the HFNC group ( P<0.05). Conclusion:For AECOPD patients receiving NIV, compared with NCO, HFNC during breaks from NIV can shorten respiratory support time and length of ICU stay, and improve carbon dioxide retention and dyspnea. HFNC is an ideal complement to NIV therapy in AECOPD patients.

Objective:To study the new mechanism of Xuebijing injection improving the function of pulmonary vascular barrier from the perspective of claudin-5 protein.Methods:Acute lung injury (ALI) model was induced by hydrogen sulfide (H 2S) exposure. ① In vivo study: Sprague-Dawley (SD) rats were divided into control group, H 2S exposure group (exposure to 300×10 -6 H 2S for 3 hours), Xuebijing control group (Xuebijing injection 4 mL/kg, twice a day, for 3 days), and Xuebijing intervention group (H 2S exposure after pretreatment of Xuebijing injection) according to random number method, with 6 rats in each group. At different time points (0, 6, 12 and 24 hours) after the model was made successfully, the total protein content in plasma and bronchoalveolar lavage fluid (BALF) of rats were detected respectively, and the pulmonary permeability index (PPI) was calculated (PPI = protein content in BALF/protein content in plasma), lung dry/wet weight ratio (W/D) was detected, and claudin-5 mRNA expression in lung tissue was measured by real time-polymerase chain reaction. ② In vitro test: human pulmonary microvascular endothelial cells (HPMECs) were divided into blank control group, NaHS treatment group (co-incubated with 500 μmol/L NaHS for 12 hours), Xuebijing control group (2 g/L Xuebijing injection for 24 hours), and Xuebijing intervention group (2 g/L Xuebijing injection pre-treated for 24 hours, then co-incubated with 500 μmol/L NaHS for 12 hours). The HPMECs claudin-5 protein expression and monolayer permeability changes were measured at different co-incubation time (1, 3, 6, 12 and 24 hours) by Western Blot and fluoresceinsodium. Results:① In vivo study: compared with the control group, the lung W/D ratio increased significantly at 6 hours and peaked at 12 hours after H 2S exposure in rats (4.67±0.11 vs. 4.26±0.06, P < 0.01). The expression of claudin-5 mRNA in lung tissue was significantly decreased, which was 89% of control group 6 hours after exposure ( P < 0.01). The total protein content in BALF and PPI at 12 hours after exposure were significantly higher than those in the control group [total protein content (mg/L): 262.31±14.24 vs. 33.30±3.09, PPI: (11.72±0.57)×10 -3 vs. (1.21±0.08)×10 -3, both P < 0.01], while the results in Xuebijing intervention group were significantly decreased [total protein content (mg/L): 153.25±7.32 vs. 262.31±14.24, PPI: (5.79±0.23)×10 -3 vs. (11.72±0.57)×10 -3, both P < 0.01]. ② In vitro test: compared with the blank control group, after incubating HPMECs with NaHS, the permeability of monolayer endothelial cells gradually increased, reaching the highest level in 12 hours, about twice of that in the blank control group, while claudin-5 protein expression decreased to the lowest level at 12 hours (claudin-5/β-actin: 0.42±0.03 vs. 1.03±0.05, P < 0.01). After intervention with Xuebijing, the permeability of endothelial cells was significantly improved (fluorescence intensity of fluorescein sodium: 1.46±0.10 vs. 1.89±0.11, P < 0.01), and the decrease of claudin-5 protein was reduced (claudin-5/β-actin: 0.68±0.04 vs. 0.38±0.03, P < 0.01). Conclusion:Xuebijing injection may improve pulmonary vascular barrier function in ALI by upregulating claudin-5 expression.

Objective To investigate the benefits and risks of stress ulcer prevention (SUP) using proton pump inhibitors (PPI) for critical patients. Methods The clinical data of adult critically ill patients admitted to the intensive care unit (ICU) of Northern Jiangsu People's Hospital from January 2016 to December 2018 were retrospectively analyzed. All patients who were treated with PPI for SUP within the first 48 hours after ICU admission were enrolled in the SUP group. Those who not received PPI were enrolled in the control group. A one-to-one propensity score matching (PSM) was performed to control for potential biases. The gender, age, underlying diseases, main diagnosis of ICU, drug use before ICU admission, sequential organ failure score (SOFA) at ICU admission, risk factors of stress ulcer (SU) and PPI usage were recorded. The end point was the incidence of gastrointestinal bleeding, hospital acquired pneumonia, Clostridium difficile infection and 30-day mortality. Kaplan-Meier survival curves were plotted, and survival analysis was performed using the log-rank test. Results 1 972 critical patients (788 in the SUP group and 1 184 in the control group) were enrolled, and each group enrolled 358 patients after PSM. Prior to PSM, compared with the control group, the SUP group had older patients, more underlying diseases, higher proportion of acute coronary syndrome (ACS), acute cerebrovascular disease, acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and poisoning in main diagnosis of ICU, more serious illness, and more risk factors of SU, indicating that ICU physicians were more likely to prescribe SUP for these patients. The incidence of gastrointestinal bleeding in the SUP group was significantly lower than that in the control group [1.8% (14/788) vs. 3.7% (44/1 184), P < 0.05], while the incidence of hospital acquired pneumonia and 30-day mortality were significantly higher than those in the control group [6.6% (52/788) vs. 3.5% (42/1 184), 17.9% (141/788) vs. 13.1% (155/1 184), both P < 0.01]. There was no significant difference in the incidence of Clostridium difficile infection between the SUP group and the control group [2.9% (23/788) vs. 1.8% (21/1 184), P >0.05]. After the propensity scores for age, underlying diseases, severity of illness and SU risk factors were matched, there was no significant difference in the incidence of gastrointestinal bleeding or 30-day mortality between the SUP group and the control group [2.2% (8/358) vs. 3.4% (12/358), 15.9% (57/358) vs. 13.7% (49/358), both P > 0.05], but the incidence of hospital acquired pneumonia in the SUP group was still significantly higher than that in the control group [6.7% (24/358) vs. 3.1% (11/358), P < 0.05]. Kaplan-Meier survival curve analysis showed that the 30-day cumulative survival rate of the SUP group was significantly lower than that of the control group before the PSM (log-rank test: χ2 = 9.224, P = 0.002). There was no significant difference in the 30-day cumulative survival rate between the two groups after PSM (log-rank test: χ2 = 0.773, P = 0.379). Conclusion For critical patients, the use of PPI for SUP could not significantly reduce the incidence of gastrointestinal bleeding and mortality, but increase the risk of hospital acquired pneumonia.

Objective To approach the predictive value of continuous monitoring end-tidal carbon dioxide partial pressure (PETCO2) on the outcome of in-hospital cardiopulmonary resuscitation (CPR), and explored the indicators of termination of resuscitation. Methods A secondary analysis of a multicenter observational study data was conducted. The screening aim was adult non-traumatic in-hospital CPR patients whose PETCO2were recorded within 30 minutes of CPR. Clinical information was reviewed. The mean PETCO2in restoration of spontaneous circulation (ROSC) and non-ROSC patients was recorded. The outcome of CPR was continuously assessed by PETCO2≤ 10 mmHg (1 mmHg = 0.133 kPa) for 1, 3, 5, 8, 10 minutes. Receiver operating characteristic (ROC) curve was plotted, and the predictive value of PETCO2≤ 10 mmHg for different duration on the outcome of CPR was evaluated. Results A total of 467 recovery patients, including 419 patients with complete recovery were screened. Patients who were out-of-hospital resuscitation, non-adults, traumatic injury, had no PETCO2value, PETCO2value failed to explained the clinical conditions, or patients had not monitored PETCO2within 30 minutes of resuscitation were excluded, and finally 120 adult patients with non-traumatic in-hospital resuscitation were enrolled in the analysis. The mean PETCO2in 50 patients with ROSC was significantly higher than that of 70 non-ROSC patients [mmHg: 17 (11, 27) vs. 9 (6, 16), P < 0.01]. ROC curve analysis showed that the area under ROC curve (AUC) of PETCO2during the resuscitation for predicting recovery outcome was 0.712 [95% confidence interval (95%CI) = 0.689-0.735]; when the cut-off was 10.5 mmHg, the sensitivity was 57.8%, and the specificity was 78.0%, the positive predictive value (PPV) was 84.6%, and negative predictive value (NPV) was 46.9%. The duration of PETCO2≤ 10 mmHg was used for further analysis, which showed that with PETCO2≤10 mmHg in duration, the prediction of the sensitivity of the patients failed to recover decreased from 58.2% to 28.2%, but specificity increased from 39.4% to 100%; PPV increased from 40% to 100%, and NPV decreased from 57.5% to 34.2%. Conclusion For adult non-traumatic in-hospital CPR patients, continuous 10 minutes PETCO2≤10 mmHg may be an indicate of termination of CPR.

Objective To compare the efficacy of high flow nasal cannula oxygen therapy (HFNC) and non-invasive ventilation (NIV) in the treatment of chronic obstructive pulmonary disease (COPD) with acute-moderate type Ⅱ respiratory failure,and to explore the feasibility of HFNC in the treatment of COPD with respiratory failure.Methods Patients diagnosed with COPD with acute moderate type Ⅱ respiratory failure (Arterial blood gas pH 7.25-7.35,PaCO2＞ 50 mmHg) admitted to the ICUs from April 2017 to December 2017 were retrospectively analyzed.All patients who were treated with HFNC within the first 4 hours after the admission to the ICUs,and continued for more than 2 hours and for at least 4 hours within the first 24 hours were included in the HFNC group.Those treated with NIV in the same conditions were included in the NIV group.The end point was the failure rates of treatment (changing to respiratory support method in another group or invasive ventilation) and 28-day mortality.Results Eighty-two patients (39 in the HFNC group and 43 in the NIV group) were enrolled.The HFNC group had a treatment failure rate of 28.2％,which was lower than that of the NIV group (39.5％).However,Kaplan-Meier curve analysis showed no significant difference between the two groups (Log Rank test 1.228,P=0.268).The 28-day mortality rate in HFNC group was 15.4％,which was no different from 14％ in NIV group (Log Rank test 0.049,P=0.824).The number of airway care interventions within the first 24 hours was significantly lower in the HFNC group than in the NIV group [5 (3～8) vs.11 (7～15)],whereas the duration of respiratory support within the first 24 hours was significantly longer in the HFNC group than in the NIV group [16 (9～22) hours vs.8 (4～11) hours] (all P＜0.05).The incidence of nasal facial lesions in the NIV group was 20.9％,significantly higher than that of HFNC group (5.1％,P ＜0.05).Conclusion For COPD with acute moderate type Ⅱ respiratory failure,HFNC has similar therapeutic effects as NIV.HFNC has better therapeutic tolerance and is a new potential respiratory support method for clinical treatment of COPD with respiratory failure.