Hypocapnia is associated with increased in-hospital mortality and 1 year mortality in acute heart failure patients.

AIMS: Both hypercapnia and hypocapnia are common in patients with acute heart failure (AHF), but the association between partial pressure of arterial carbon dioxide (PaCO2) and AHF prognosis remains unclear. The objective of this study was to investigate the connection between PaCO2 within 24 h after admission to the intensive care unit (ICU) and mortality during hospitalization and at 1 year in AHF patients. METHODS AND RESULTS: AHF patients were enrolled from the Medical Information Mart for Intensive Care IV database. The patients were divided into three groups by PaCO2 values of <35, 35-45, and >45 mmHg. The primary outcome was to investigate the connection between PaCO2 and in-hospital mortality and 1 year mortality in AHF patients. The secondary outcome was to assess the prediction value of PaCO2 in predicting in-hospital mortality and 1 year mortality in AHF patients. A total of 2374 patients were included in this study, including 457 patients in the PaCO2 < 35 mmHg group, 1072 patients in the PaCO2 = 35-45 mmHg group, and 845 patients in the PaCO2 > 45 mmHg group. The in-hospital mortality was 19.5%, and the 1 year mortality was 23.9% in the PaCO2 < 35 mmHg group. Multivariate logistic regression analysis showed that the PaCO2 < 35 mmHg group was associated with an increased risk of in-hospital mortality [hazard ratio (HR) 1.398, 95% confidence interval (CI) 1.039-1.882, P = 0.027] and 1 year mortality (HR 1.327, 95% CI 1.020-1.728, P = 0.035) than the PaCO2 = 35-45 mmHg group. The PaCO2 > 45 mmHg group was associated with an increased risk of in-hospital mortality (HR 1.387, 95% CI 1.050-1.832, P = 0.021); the 1 year mortality showed no significant difference (HR 1.286, 95% CI 0.995-1.662, P = 0.055) compared with the PaCO2 = 35-45 mmHg group. The Kaplan-Meier survival curves showed that the PaCO2 < 35 mmHg group had a significantly lower 1 year survival rate. The area under the receiver operating characteristic curve for predicting in-hospital mortality was 0.591 (95% CI 0.526-0.656), and the 1 year mortality was 0.566 (95% CI 0.505-0.627) in the PaCO2 < 35 mmHg group. CONCLUSIONS: In AHF patients, hypocapnia within 24 h after admission to the ICU was associated with increased in-hospital mortality and 1 year mortality. However, the increase in 1 year mortality may be influenced by hospitalization mortality. Hypercapnia was associated with increased in-hospital mortality.

The effects of dexmedetomidine for patient-controlled analgesia on postoperative sleep quality and gastrointestinal motility function after surgery: A prospective, randomized, double-blind, and controlled trial.

Background: Postoperative poor sleep quality and decreased gastrointestinal motility function are common clinical problems. This study investigated the effects of dexmedetomidine (DEX) combined with sufentanil for patient-controlled analgesia (PCA) on postoperative sleep quality and gastrointestinal motility function after surgery in patients with colorectal cancer. Methods: Patients undergoing colorectal cancer surgery were randomly divided into three groups, DEX 0, 200, or 400 µg, each combined with sufentanil 150 µg for PCA immediately after surgery. The primary outcome was sleep quality in the first 7 days after surgery based on the Athens Insomnia Scale (AIS) score. The secondary outcome was postoperative gastrointestinal motility recovery evaluated by the time of first flatus, first feces and first diet. Postoperative pain intensity, side effects and the length of postoperative hospital stay were also compared among groups. The study was registered with the Chinese Clinical Trial Registry (https://www.chictr.org.cn/enIndex.aspx, ChiCTR2000032601). Results: Ultimately, 210 cases were included. Sleep quality was better in the DEX 200 µg group and DEX 400 µg group than in the DEX 0 µg group. Overall, in the DEX 200 µg group and DEX 400 µg group, the AIS score (p < 0.05) and the incidence of sleep disturbance (7.3%, 4.5% vs. 19.6%, p < 0.001) were lower than those in the DEX 0 µg group in the first 7 days after surgery. There were no significant differences in postoperative gastrointestinal motility among the three groups in the total surgical categories (p > 0.05). In the laparoscopic surgery patients of each group, the time of postoperative first flatus (p = 0.02) and first feces (p = 0.01) was significantly longer in the DEX 400 µg group than in the DEX 0 µg group. There were no differences in postoperative pain intensity, side effects or length of postoperative hospital stay (p > 0.05). Conclusion: The continuous infusion of DEX (200 or 400 µg) for PCA significantly improved postoperative sleep quality after colorectal cancer surgery. DEX (200 µg) was better at improving postoperative sleep quality without affecting gastrointestinal motility function than DEX (400 µg) in patients who underwent laparoscopic colorectal cancer surgery.

The Design and Evaluation of a Portable Extracorporeal Centrifugal Blood Pump.

In recent years, blood pumps have become the bridge to heart transplantation for patients with heart failure. Portability and wearability of blood pumps should be considered to ensure patient satisfaction in everyday life. To date, the focus has been on the development of portable and wearable peripheral components, little attention has been paid to the portable and wearable performance of the blood pump itself. This study reported a novel design of a wearable and portable extracorporeal centrifugal blood pump. Based on an in-house centrifugal maglev blood pump, the wearable and portable blood pump was designed with parallel inlet and outlet pipes to improve the wearable performance. A ring cavity was set at the inlet to convert the circumferential velocity of the inlet pipe to an axial velocity. The hydraulic and hemolytic performance of the baseline and portable blood pumps were analyzed and compared. Compared with the baseline pump, the hydrodynamic and hemolytic performance of the portable pump has been maintained without serious degradation. The results of this study will improve the life quality of patients with heart failure, and enhance the clinical benefits of artificial heart.

On the Optimization of a Centrifugal Maglev Blood Pump Through Design Variations.

Centrifugal blood pumps are usually designed with secondary flow paths to avoid flow dead zones and reduce the risk of thrombosis. Due to the secondary flow path, the intensity of secondary flows and turbulence in centrifugal blood pumps is generally very high. Conventional design theory is no longer applicable to centrifugal blood pumps with a secondary flow path. Empirical relationships between design variables and performance metrics generally do not exist for this type of blood pump. To date, little scientific study has been published concerning optimization and experimental validation of centrifugal blood pumps with secondary flow paths. Moreover, current hemolysis models are inadequate in an accurate prediction of hemolysis in turbulence. The purpose of this study is to optimize the hydraulic and hemolytic performance of an inhouse centrifugal maglev blood pump with a secondary flow path through variation of major design variables, with a focus on bringing down intensity of turbulence and secondary flows. Starting from a baseline design, through changing design variables such as blade angles, blade thickness, and position of splitter blades. Turbulent intensities have been greatly reduced, the hydraulic and hemolytic performance of the pump model was considerably improved. Computational fluid dynamics (CFD) combined with hemolysis models were mainly used for the evaluation of pump performance. A hydraulic test was conducted to validate the CFD regarding the hydraulic performance. Collectively, these results shed light on the impact of major design variables on the performance of modern centrifugal blood pumps with a secondary flow path.