Therapeutic plasma exchange in the intensive care unit: Rationale, special considerations, and techniques for combined circuits

Comparison of efficacy and safety of different anticoagulation regimens in plasma exchange: A systematic review and meta-analysis

BACKGROUND

Extracorporeal line clotting during plasma exchange (PE) not only delays efficient treatment, but also cause great waste of nursing resources. There is a lack of comprehensive comparison of the efficacy and safety among different anticoagulation regimens in plasma exchange in literature.

METHODS

A systematic search was performed in EMBASE, MEDLINE via PubMed, Cochrane Central Library, and CNKI. Studies that had compared at least two anticoagulation regimens in PE were considered eligible. The anticoagulative efficacy outcome was assessed by the occurrence of extracorporeal circuit clotting. The safety outcome was assessed by the occurrence of bleeding events, post-treatment APTT values, and post-treatment platelets counts. The risk of bias was assessed by the AHRQ tool. Mean differences or standardized mean differences with 95% confidence intervals (CIs) of continuous variables and risk ratios (RRs) with 95% CIs of categorical variables were pooled using a random-effects or a fixed-effects model as appropriate.

RESULTS

In all, 7 studies with 1638 patients and 10951 sessions of PE treatment were included. Pooled results indicated the anticoagulative efficacy of UFH was better than that of saline flushing, yet did not differ with those of LMWH or RCA. Although the occurrence of bleeding events had no difference among different pairs of anticoagulation regimens, anticoagulation using UFH might lead to longer post-treatment APTT value and lower post-treatment platelet counts. Only one study was judged to have low risk of bias in each of the five domains in the AHRQ tool.

CONCLUSIONS

The current anticoagulation regimens are generally effective and well tolerated in PE; however, the number of included studies was too limited to draw definitive conclusions.

Management of Bivalirudin Dosing and Replacement Fluid During Therapeutic Plasma Exchange in Children on Extracorporeal Membrane Oxygenation

The use of bivalirudin as the primary anticoagulant for children supported on extracorporeal membrane oxygenation (ECMO) is growing. Ideal management of bivalirudin dosing during therapeutic plasma exchange (TPE) on ECMO is unknown. We performed a single-center retrospective study of ECMO patients anticoagulated with bivalirudin who underwent TPE from January 2019 to December 2021. Therapeutic plasma exchange sessions were analyzed individually by bivalirudin dosing strategy (no change [NC] versus increased dose [dose change {DC} bivalirudin group]) and replacement fluid (all fresh-frozen plasma [FFP] versus all albumin or FFP and albumin [FFP/Albumin]). Primary outcomes included bleeding, coagulopathy, and circuit thrombosis within 24 hours of TPE. Secondary outcomes included change in bivalirudin dose and coagulation parameters following TPE. There were 60 unique TPE sessions. Bivalirudin dosing or replacement fluid strategies were not associated with bleeding, coagulopathy, or thrombosis post-TPE. All albumin or fresh frozen plasma and albumin combinations (FFP/Albumin) group had longer post-TPE thromboelastography (TEG) reaction time, clot time, and more acute angle. The FFP/Albumin group had increased post-TPE international normalization ratio (INR) and partial thrombin time (PTT). Therapeutic plasma exchange for children on ECMO and bivalirudin anticoagulation is feasible; however, optimal dosing during TPE requires further investigation. Replacement fluid with FFP/Albumin is associated with more coagulopathic laboratory parameters. Patients may benefit from all FFP fluid replacement strategy. Further investigation is needed to prove generalizability.

Prevalence of extracorporeal blood purification techniques in critically ill patients before and during the COVID-19 pandemic in Egypt

BACKGROUND

Extracorporeal blood-purification techniques are frequently needed in the pediatric intensive care unit (PICU), yet data on their clinical application are lacking. This study aims to review the indications, rate of application, clinical characteristics, complications, and outcomes of patients undergoing extracorporeal blood purification (i.e., by continuous renal replacement therapy [CRRT] or therapeutic plasma exchange [TPE]) in our PICU, including before the coronavirus disease 2019 (COVID-19) pandemic in 2019 and during the pandemic from 2020 to 2022.

METHODS

This study included children admitted for extracorporeal blood-purification therapy in the PICU. The indications for TPE were analyzed and compared to the American Society for Apheresis categories.

RESULTS

In 82 children, 380 TPE sessions and 37 CRRT sessions were carried out children, with 65 patients (79%) receiving TPE, 17 (20.7%) receiving CRRT, and four (4.8%) receiving both therapies. The most common indications for TPE were neurological diseases (39/82, 47.5%), followed by hematological diseases (18/82, 21.9%). CRRT was mainly performed for patients suffering from acute kidney injury. Patients with neurological diseases received the greatest number of TPE sessions (295, 77.6%). Also, the year 2022 contained the greatest number of patients receiving extracorporeal blood-purification therapy (either CRRT or TPE).

CONCLUSIONS

The use of extracorporeal blood-purification techniques increased from 2019 through 2022 due to mainly autoimmune dysregulation among affected patients. TPE can be safely used in an experienced PICU. No serious adverse events were observed in the patients that received TPE, and overall survival over the 4 years was 86.5%.

Plasmapheresis in the ICU

Therapeutic plasma exchange (TPE) is a treatment paradigm used to remove harmful molecules from the body. In short, it is a technique that employs a process that functions partially outside the body and involves the replacement of the patient's plasma. It has been used in the ICU for a number of different disease states, for some as a first-line treatment modality and for others as a type of salvage therapy. This paper provides a brief review of the principles, current applications, and potential future directions of TPE in critical care settings.

Liver replacement therapy with extracorporeal blood purification techniques current knowledge and future directions

Clinically, it is highly challenging to promote recovery in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Despite recent advances in understanding the underlying mechanisms of ALF and ACLF, standard medical therapy remains the primary therapeutic approach. Liver transplantation (LT) is considered the last option, and in several cases, it is the only intervention that can be lifesaving. Unfortunately, this intervention is limited by organ donation shortage or exclusion criteria such that not all patients in need can receive a transplant. Another option is to restore impaired liver function with artificial extracorporeal blood purification systems. The first such systems were developed at the end of the 20^th century, providing solutions as bridging therapy, either for liver recovery or LT. They enhance the elimination of metabolites and substances that accumulate due to compromised liver function. In addition, they aid in clearance of molecules released during acute liver decompensation, which can initiate an excessive inflammatory response in these patients causing hepatic encephalopathy, multiple-organ failure, and other complications of liver failure. As compared to renal replacement therapies, we have been unsuccessful in using artificial extracorporeal blood purification systems to completely replace liver function despite the outstanding technological evolution of these systems. Extracting middle to high-molecular-weight and hydrophobic/protein-bound molecules remains extremely challenging. The majority of the currently available systems include a combination of methods that cleanse different ranges and types of molecules and toxins. Furthermore, conventional methods such as plasma exchange are being re-evaluated, and novel adsorption filters are increasingly being used for liver indications. These strategies are very promising for the treatment of liver failure. Nevertheless, the best method, system, or device has not been developed yet, and its probability of getting developed in the near future is also low. Furthermore, little is known about the effects of liver support systems on the overall and transplant-free survival of these patients, and further investigation using randomized controlled trials and meta-analyses is needed. This review presents the most popular extracorporeal blood purification techniques for liver replacement therapy. It focuses on general principles of their function, and on evidence regarding their effectiveness in detoxification and in supporting patients with ALF and ACLF. In addition, we have outlined the basic advantages and disadvantages of each system.