A Multi-Center Cross-Sectional Study on Blood Purification Among Adult Patients in Intensive Care Unit in China: A Study Protocol
Introduction
In the intensive care unit (ICU), acute kidney injury (AKI) is a common and severe complication of critical illnesses, often referred to as a “silent killer.” AKI is an independent risk factor for increased mortality, and its incidence has been rising dramatically in recent years. Despite advancements in understanding the causes and pathogenesis of AKI, the associated mortality remains high, posing a significant medical burden both in China and globally. Currently, there is no effective drug treatment for AKI, making prevention a crucial strategy to avoid adverse outcomes. Approximately 20% of patients with AKI require blood purification (BP), a demand that continues to grow. The purpose of BP has evolved from merely replacing kidney function to providing multiple organ support therapy, treating critically ill patients holistically.
Beyond AKI, BP is widely utilized for various non-AKI critical illnesses, including septic shock, acute respiratory distress syndrome, heart failure, cardiorenal syndrome, pulmonary edema, fluid overload, drug and food poisonings, acute pancreatitis, liver failure, rhabdomyolysis syndrome, and life-threatening acid-base and ion disturbances. These applications have demonstrated considerable clinical outcomes, establishing BP as a vital therapeutic tool for clinicians in the treatment and rescue of critically ill patients. However, significant disparities exist in clinical practice, exacerbated by the absence of standardized guidelines and consensus.
Despite progress in BP technology and clinical practice over the past decades, many aspects remain controversial. Key areas of debate include the optimal timing for initiating renal replacement therapy (RRT), anticoagulation strategies, and RRT dosing. These uncertainties have led to wide variations in BP practices across ICUs worldwide. It is urgent to develop standardized treatment guidelines for BP in China to improve and standardize clinical practice, ultimately enhancing patient outcomes. As a first step toward this goal, it is essential to thoroughly understand the current BP practices in ICUs across China. This multi-center cross-sectional survey aims to reveal the real-world scenario of BP practices in Chinese ICUs, laying the foundation for future guideline development.
Methods
Study Design
This multi-center cross-sectional survey includes 35 sub-centers across China, located in 23 provinces, four municipalities, and five autonomous regions. Given the unique population distribution and regional differences in Beijing, Shanghai, and Guangzhou, each of these cities will recruit two tertiary grade A hospitals. The survey period spans 30 days, during which all physicians involved will receive professional training. Demographic and clinical data of enrolled patients will be collected, including the timing of treatment initiation, indications, modality, relative contraindications, establishment of vascular access, selection of filter/membrane, settings, anticoagulation, executive department, complications, and intake and output. Additionally, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, Sequential Organ Failure Assessment (SOFA) scores, and Glasgow Coma Scale (GCS) scores will be obtained through medical record reviews. Patient confidentiality will be maintained throughout the study.
Ethics and Dissemination
The study adheres to the ethical principles of the Declaration of Helsinki and has been approved by the Ethics Committee of the Cancer Hospital of Harbin Medical University (No. KY2017-22). Written informed consent will be obtained from each eligible adult participant or their legally authorized representative before enrollment. Participants may withdraw from the study at any time, and their data will be counted and analyzed accordingly. The findings will be disseminated through articles and presentations at national and international conferences, contributing to the reflection of current BP practices in Chinese ICUs and the standardization of clinical practice.
Study Participants
Inclusion criteria for the study are: (1) admission to the ICU; (2) age 18 years or older; and (3) the need for BP. Patients who are readmitted to the ICU during the 30-day study period will be re-enrolled. There are no specific exclusion criteria, but patients without written informed consent or incomplete medical records will be excluded.
Sample Size Calculation
The study aims to enroll at least 369 subjects. The sample size calculation is based on an infinite population sample formula, considering a population rate of 0.02 and an allowable error of 0.01. Based on recent reports, out of 6,147 patients, approximately 1,229 (20%) are expected to develop AKI, with 184 (15%) requiring RRT. Since BP encompasses various clinical treatments, including RRT, the sample size is doubled to 369 to ensure comprehensive data collection.
Statistical Analysis
Statistical analysis will be performed using SPSS 22.0 and SAS 9.1 software. Quantitative data will be presented as mean ± standard deviation for normally distributed data and median (quantile) for non-normally distributed data. Qualitative data will be expressed as percentages. The Student’s t-test or Mann-Whitney U test will be used to compare quantitative data between groups, while the Chi-squared test will be used for qualitative data. A p-value of less than 0.05 will be considered statistically significant.
Discussion
Blood purification is a broad term encompassing various technologies used in clinical practice, including intermittent hemodialysis (IHD), hemofiltration, hemodiafiltration, hemoperfusion, plasmapheresis, immune adsorption, and peritoneal dialysis. BP involves drawing a patient’s blood out of the body to remove pathogenic substances, achieving purification and treating critical illnesses through devices that utilize principles of diffusion, convection, and adsorption. Different BP modalities focus on different principles, making them suitable for various clinical scenarios. For example, IHD primarily relies on diffusion, continuous RRT on convection, and hemoperfusion on adsorption.
The application of BP in ICUs began in 1977 with continuous arteriovenous hemofiltration for AKI patients unsuitable for peritoneal dialysis and hemodialysis. This marked the start of a flourishing evolution in BP technology. The introduction of double-lumen central venous catheters, blood pumps, and calibrated ultrafiltration control systems significantly improved the safety and efficacy of continuous venovenous hemofiltration, making it the mainstream RRT technique in ICUs. Despite these advancements, many challenges remain.
As the world’s most populous and largest developing country, China faces unique challenges in medical care, including underestimation and undertreatment of AKI due to lack of awareness, limited medical resources, and low socio-economic status. The absence of standardized guidelines and consensus on BP has led to significant practice heterogeneity in areas such as treatment timing, indications, modality, vascular access, filter/membrane selection, settings, anticoagulation, and executive departments. This underscores the urgent need for standardized treatment guidelines in China to improve and standardize clinical practice.
This nationwide survey represents the largest and most comprehensive effort to date to understand BP practices in Chinese ICUs. By revealing the real-world scenario of BP practices, the study aims to lay the foundation for developing standardized treatment guidelines, ultimately improving outcomes for critically ill patients.
Conclusion
This multi-center cross-sectional survey on blood purification among adult ICU patients in China is a critical step toward understanding and standardizing BP practices. By collecting comprehensive data from 35 sub-centers across the country, the study aims to reflect the real-world scenario of BP practices, identify areas of heterogeneity, and provide a foundation for future guideline development. The findings will contribute to improving clinical practice and patient outcomes, addressing the urgent need for standardized BP treatment in China.
doi.org/10.1097/CM9.0000000000000180
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