Use of nafamostat mesilate as an anticoagulant during extracorporeal membrane oxygenation

Anticoagulants in adult extracorporeal membrane oxygenation: alternatives to standardized anticoagulation with unfractionated heparin

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a vital technique for severe respiratory or heart failure patients. Bleeding and thrombotic events are common during ECMO and negatively impact patient outcomes. Unfractionated heparin is the primary anticoagulant, but its adverse effects limit its use, necessitating alternative anticoagulants.

OBJECTIVE

Review available alternative anticoagulants for adult ECMO patients. Explore potential novel anticoagulants for future ECMO use. Aim to reduce complications (bleeding and thrombosis) and improve safety and efficacy for critically ill ECMO patients.

METHODS

Comprehensive literature review of existing and emerging anticoagulants for ECMO.

RESULTS

Identified a range of alternative anticoagulants beyond unfractionated heparin. Evaluated their potential utility in mitigating ECMO-related complications.

CONCLUSION

Diverse anticoagulant options are available and under investigation for ECMO. These alternatives may enhance patient safety and outcomes during ECMO support. Further research and clinical studies are warranted to determine their effectiveness and safety profiles.

Anticoagulation strategies in patients with extracorporeal membrane oxygenation: A network meta-analysis and systematic review

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) plays an important role in providing temporary life support for patients with severe cardiac or pulmonary failure, but requires strict anticoagulation and monitoring. This network meta-analysis systematically explored the most effective anticoagulation and monitoring strategies for patients receiving ECMO.

METHODS

MEDLINE, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to January 31, 2023, for studies comparing unfractionated heparin (UFH), argatroban (Arg), bivalirudin (Biv), and/or nafamostat mesylate (NM) in patients receiving ECMO. The primary outcomes included device-related thrombosis, patient-related thrombosis, and major bleeding events. The secondary outcomes included ECMO survival, ECMO duration, and in-hospital mortality.

RESULTS

A total of 2522 patients from 23 trials were included in the study. Biv was associated with a decreased risk of device-related thrombosis (odd ratio [OR] 0.51, 95% confidence interval [CI]: 0.33-0.84) compared with UFH, whereas NM (OR 2.2, 95% CI: 0.24-65.0) and Arg (OR 0.92, 95% CI: 0.43-2.0) did not reduce the risk of device-related thrombosis compared with UFH. Biv was superior to Arg in decreasing the risk of device-related thrombosis (OR 0.14, 95% CI: 0.03-0.51). Biv reduced the risk of patient-related thrombosis compared with UFH (OR 0.44, 95% CI: 0.18-0.85); NM (OR 0.65, 95% CI: 0.14-3.3) and Arg (OR 3.1, 95% CI: 0.94-12.0) did not decrease risk of patient-related thrombosis compared with UFH. No significant difference was observed in the risk of major bleeding between three alternatives and UFH: Biv (OR 0.54, 95% CI: 0.23-1.3), Arg (OR 1.3, 95% CI: 0.34-5.8), and NM (OR 0.60, 95% CI: 0.13-2.6). NM showed a reduced risk of in-hospital mortality compared with UFH (OR 0.27, 95% CI: 0.091-0.77), whereas Arg (OR 0.43, 95% CI: 0.15-1.2) and Biv (OR 0.75, 95% CI: 0.52-1.1) did not decrease risk of in-hospital mortality.

CONCLUSIONS

Compared with UFH and Arg, Biv reduces the risk of thrombosis and appears to be a better choice for patients requiring ECMO. NM was associated with a reduced risk of in-hospital mortality.

Application of nafamostat mesylate for anticoagulation in hemoperfusion therapy in patients with bromadiolone poisoning: Case reports

Bromadiolone, as a second-generation coumarin anticoagulant rodenticide, may accidently cause harm to humans and non-target animals when overused or misused due to its high toxicity and long-lasting effects. In some severe cases such as the presence of active bleeding, treatment should involve the administration of hemoperfusion therapy. Nafamostat mesylate is a synthesized protease inhibitor that inhibits most factors in the coagulation process, preventing clotting and ensuring smooth blood flow during the procedure. Nafamostat mesylate helps maintain the efficacy and safety of hemoperfusion treatment. Despite its wide application in Japan, the clinical practice and research of nafamostat mesylate are limited in China, especially for patients undergoing maintenance hemodialysis. This paper reports two cases of bromadiolone poisoning and describes the treatment procedure and therapeutic effect of anticoagulation in hemoperfusion therapy with nafamostat mesylate.

Anticoagulation in adult patients supported with extracorporeal membrane oxygenation: guidance from the Scientific and Standardization Committees on Perioperative and Critical Care Haemostasis and Thrombosis of the International Society on Thrombosis and Haemostasis

Anticoagulation of patients supported by extracorporeal membrane oxygenation is challenging because of a high risk of both bleeding and thrombotic complications, and often empirical. Practice in anticoagulation management is therefore highly variable. The scope of this guidance document is to provide clinicians with practical advice on the choice of an anticoagulant agent, dosing, and the optimal anticoagulant monitoring strategy during extracorporeal membrane oxygenation support in adult patients.

Current and future strategies to monitor and manage coagulation in ECMO patients

Extracorporeal membrane oxygenation (ECMO) can provide life-saving support for critically ill patients suffering severe respiratory and/or cardiac failure. However, thrombosis and bleeding remain common and complex problems to manage. Key causes of thrombosis in ECMO patients include blood contact to pro-thrombotic and non-physiological surfaces, as well as high shearing forces in the pump and membrane oxygenator. On the other hand, adverse effects of anticoagulant, thrombocytopenia, platelet dysfunction, acquired von Willebrand syndrome, and hyperfibrinolysis are all established as causes of bleeding. Finding safe and effective anticoagulants that balance thrombosis and bleeding risk remains challenging. This review highlights commonly used anticoagulants in ECMO, including their mechanism of action, monitoring methods, strengths and limitations. It further elaborates on existing anticoagulant monitoring strategies, indicating their target range, benefits and drawbacks. Finally, it introduces several highly novel approaches to real-time anticoagulation monitoring methods including sound, optical, fluorescent, and electrical measurement as well as their working principles and future directions for research.

Efficacy and safety of nafamostat mesilate anticoagulation in blood purification treatment of critically ill patients: a systematic review and meta-analysis

BACKGROUND

Nafamostat mesilate (NM), a broad-spectrum and potent serine protease inhibitor, can be used as an anticoagulant during extracorporeal circulation, as well as a promising drug effective against coronavirus disease 2019 (COVID-19). We conducted a systematic meta-analysis to evaluate the safety and efficacy of NM administration in critically ill patients who underwent blood purification therapy (BPT).

METHODS

The Cochrane Library, Web of Science and PubMed were comprehensively searched from inception to August 20, 2021, for potential studies.

RESULTS

Four randomized controlled trials (RCTs) and seven observational studies with 2723 patients met the inclusion criteria. The meta-analysis demonstrated that conventional therapy (CT) significantly increased hospital mortality compared with NM administration (RR = 1.25, p = 0.0007). In subgroup analyses, the in-hospital mortality of the NM group was significantly lower than that of the anticoagulant-free (NA) group (RR = 1.31, p = 0.002). The CT interventions markedly elevated the risk ratio of bleeding complications by 45% (RR = 1.45, p = 0.010) compared with NM interventions. In another subgroup analysis, NM used exhibited a significantly lower risk of bleeding complications than those of the low-molecular-weight heparin (LMWH) used (RR = 4.58, p = 0.020). The filter lifespan was decreased significantly (MD = -10.59, p < 0.0001) in the NA groups compared with the NM groups. Due to the poor quality of the included RCTs, these results should be interpreted with caution.

CONCLUSION

Given the better survival outcomes, lower risk of bleeding, NM anticoagulation seems to be a safe and efficient approach for BPT patients and could yield a favorable filter lifespan. More multi-center RCTs with large samples are required for further validation of this study.

Anticoagulation with nafamostat mesilate during extracorporeal life support

Nafamostat mesylate (NM) affects coagulation and fibrinolysis and impedes obesity-associated protein demethylase activity, which regulates Na+/K+ transport properties and the NF-κB signaling pathway. NM significantly decreases macrophage, neutrophil, and T lymphocyte infiltration, thereby reducing inflammation and apoptosis after reperfusion and promoting recovery in patients with severe conditions such as near-fatal asthma and cardiac arrest. Extracorporeal life support (ECLS) devices are used for cardiac and/or pulmonary support as a bridge to recovery, decision, surgery, or transplant in patients with refractory cardio-circulatory or respiratory diseases and provide essential opportunities for organ support and patient survival. However, they can lead to some potential adverse events such as hemorrhage and thrombosis. NM provides a sustained innate immune response of coagulation and anti-inflammation in extracorporeal circuits, principally due to its activation of the contact and complement systems. Heparin is the main anticoagulant used in extracorporeal circuits; however, it may cause massive bleeding and heparin-induced thrombocytopenia. Although no antidote is available, NM has a very short half-life of approximately 8-10 min and might have positive effects on patients who require coagulation and anti-inflammation. NM has been used for anticoagulation in continuous renal replacement therapy, extracorporeal membrane oxygenation, hemodialysis, and left ventricular assist devices. In this review, we focused on the pharmacology, monitoring parameters, and considerations for the special use of NM in patients receiving ECLS. Our findings suggest that systemic anticoagulation with NM during ECLS might be a feasible and safe alternative with several advantages for critically ill patients with high-risk bleeding and might improve their prognosis.

Nafamostat is a Potent Human Diamine Oxidase Inhibitor Possibly Augmenting Hypersensitivity Reactions during Nafamostat Administration

Nafamostat is an approved short-acting serine protease inhibitor. However, its administration is also associated with anaphylactic reactions. One mechanism to augment hypersensitivity reactions could be inhibition of diamine oxidase (DAO). The chemical structure of nafamostat is related to the potent DAO inhibitors pentamidine and diminazene. Therefore, we tested whether nafamostat is a human DAO inhibitor. Using different activity assays, nafamostat reversibly inhibited recombinant human DAO with an IC50 of 300-400 nM using 200 µM substrate concentrations. The Ki of nafamostat for the inhibition of putrescine and histamine deamination is 27 nM and 138 nM, respectively For both substrates, nafamostat is a mixed mode inhibitor with P values of <0.01 compared with other inhibition types. Using 80-90% EDTA plasma, the IC50 of nafamostat inhibition was approximately 360 nM using 20 µM cadaverine. In 90% EDTA plasma, the IC50 concentrations were 2-3 µM using 0.9 µM and 0.18 µM histamine as substrate. In silico modeling showed a high overlap compared with published diminazene crystallography data, with a preferred orientation of the guanidine group toward topaquinone. In conclusion, nafamostat is a potent human DAO inhibitor and might increase severity of anaphylactic reaction by interfering with DAO-mediated extracellular histamine degradation. SIGNIFICANCE STATEMENT: Treatment with the short-acting anticoagulant nafamostat during hemodialysis, leukocytapheresis, extracorporeal membrane oxygenator procedures, and disseminated intravascular coagulation is associated with severe anaphylaxis in humans. Histamine is a central mediator in anaphylaxis. Potent inhibition of the only extracellularly histamine-degrading enzyme diamine oxidase could augment anaphylaxis reactions during nafamostat treatment.

Evaluation of clinical outcomes in patients treated with heparin or direct thrombin inhibitors during extracorporeal membrane oxygenation: a systematic review and meta-analysis

BACKGROUND

The number of patients treated with extracorporeal membrane oxygenation (ECMO) devices is increasing. Anticoagulation therapy is crucial to prevent thrombosis during ECMO therapy. Predominantly, heparin has been used as primary anticoagulant but direct thrombin inhibitors (DTI) have been established as alternatives. The aim of this systematic review and meta-analysis was to evaluate clinical outcomes in patients treated with heparin compared to different DTI during ECMO.

METHODS

A systematic search was conducted. Full scientific articles were sought for inclusion if heparin anticoagulation was compared to DTI (argatroban/bivalirudin) in ECMO patients. Risk of bias was assessed by Newcastle Ottawa scale. Primary endpoint was in-hospital mortality. Bleeding events, thrombotic events, hours of ECMO support, days of hospital stay, percentage of time within therapeutic range and time to therapeutic range were extracted from full texts as secondary endpoints. Results were presented as Forrest-plots. GRADE was used for confidence assessment in outcomes.

RESULTS

Systematic search identified 4.385 records, thereof 18 retrospective studies for a total of 1942 patients, complied with the predefined eligibility criteria:15 studies investigated bivalirudin and 3 studies investigated argatroban versus heparin. Risk of bias was high for most studies. In-hospital mortality, major bleeding events and pump-related thrombosis were less frequent in DTI group as compared to heparin [mortality-OR 0.69, 95% CI 0.54-0.86; major bleeding-OR 0.48, 95% CI 0.29-0.81; pump thrombosis-OR 0.55, 95% CI 0.40-0.76]. Additionally, percentage of time within therapeutic range was higher for DTI [SMD 0.54, 95% CI 0.14-0.94]. GRADE approach revealed a very low level of certainty for each outcome.

CONCLUSION

In this meta-analysis, DTI and especially bivalirudin showed beneficial effects on clinical outcomes in ECMO patients as compared to heparin. However, due to the lack of randomized trials, certainty of evidence is low.

TRIAL REGISTRATION

This systematic review and meta-analysis was prospectively registered at PROSPERO data base (reference number CRD42021237252 ).

Use of nafamostat mesilate for anticoagulation during extracorporeal membrane oxygenation: A systematic review

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) represents an advanced option for supporting refractory respiratory and/or cardiac failure. Systemic anticoagulation with unfractionated heparin (UFH) is routinely used. However, patients with bleeding risk and/or heparin-related side effects may necessitate alternative strategies: among these, nafamostat mesilate (NM) has been reported.

METHODS

We conducted a systematic literature search (PubMed and EMBASE, updated 12/08/2021), including all studies reporting NM anticoagulation for ECMO. We focused on reasons for starting NM, its dose and the anticoagulation monitoring approach, the incidence of bleeding/thrombosis complications, the NM-related side effects, ECMO weaning, and mortality.

RESULTS

The search revealed 11 relevant findings, all with retrospective design. Of these, three large studies reported a control group receiving UFH, the other were case series (n = 3) or case reports (n = 5). The main reason reported for NM use was an ongoing or high risk of bleeding. The NM dose varied largely as did the anticoagulation monitoring approach. The average NM dose ranged from 0.46 to 0.67 mg/kg/h, but two groups of authors reported larger doses when monitoring anticoagulation with ACT. Conflicting findings were found on bleeding and thrombosis. The only NM-related side effect was hyperkalemia (n = 2 studies) with an incidence of 15%-18% in patients anticoagulated with NM. Weaning and survival varied across studies.

CONCLUSION

Anticoagulation with NM in ECMO has not been prospectively studied. While several centers have experience with this approach in high-risk patients, prospective studies are warranted to establish the optimal space of this approach in ECMO.

The Transmembrane Protease TMPRSS2 as a Therapeutic Target for COVID-19 Treatment

TMPRSS2 is a type II transmembrane protease with broad expression in epithelial cells of the respiratory and gastrointestinal tract, the prostate, and other organs. Although the physiological role of TMPRSS2 remains largely elusive, several endogenous substrates have been identified. TMPRSS2 serves as a major cofactor in SARS-CoV-2 entry, and primes glycoproteins of other respiratory viruses as well. Consequently, inhibiting TMPRSS2 activity is a promising strategy to block viral infection. In this review, we provide an overview of the role of TMPRSS2 in the entry processes of different respiratory viruses. We then review the different classes of TMPRSS2 inhibitors and their clinical development, with a focus on COVID-19 treatment.

COVID-19, Angiotensin-Converting Enzyme 2 and Renin-Angiotensin System Inhibition: Implications for Practice

BACKGROUND

Recent studies suggested that patients with coronavirus disease 2019 (COVID-19) who use renin-angiotensin system (RAS) inhibitors have an increased risk of respiratory failure and death. The hypothesis was that angiotensin-converting enzyme inhibitor (ACEIs) or angiotensin receptor blocker (ARBs) might up-regulate ACE2 expression that is used as a receptor for viral entry into cells.

OBJECTIVE

The purpose of this review is to discuss the existing evidence on the interaction between COVID-19 infection, ACE2 and ACEIs or ARBs and to examine the main implications for clinical practice. In addition, novel therapeutic strategies for blocking ACE2-mediated COVID-19 infection will be displayed.

METHODS

We performed a comprehensive review of the literature to identify data from clinical and experimental studies for the association between COVID-19 infection, ACE2 and RAS inhibition.

RESULTS

The current clinical and experimental evidence for ACEIs or ARBs to facilitate severe acute respiratory distress syndrome-coronavirus-2 (SARS-CoV-2) is insufficient to suggest discontinuing these drugs. Several observational studies arrive at the conclusion that the continued use of RAS inhibitors is unlikely to be harmful in COVID-19-positive patients.

CONCLUSIONS

Further randomized trials are needed to answer the question of whether RAS inhibitors are harmful or beneficial to patients with COVID-19.

Nafamostat in hospitalized patients with moderate to severe COVID-19 pneumonia: a randomised Phase II clinical trial

BACKGROUND

Nafamostat, a serine protease inhibitor, has been used for the treatment of disseminated intravascular coagulation and pancreatitis. In vitro studies and clinical reports suggest its beneficial effect in the treatment of COVID-19 pneumonia.

METHODS

This phase 2 open-label, randomised, multicentre, controlled trial evaluated nafamostat (4.8 mg/kg/day) plus standard-of-care (SOC) in hospitalised patients with COVID-19 pneumonia (i.e., those requiring nasal high-flow oxygen therapy and/or non-invasive mechanical ventilation). The primary outcome was the time to clinical improvement. Key secondary outcomes included the time to recovery, rates of recovery and National Early Warning Score (NEWS). The trial is registered with ClinicalTrials.gov Identifier: NCT04623021.

FINDINGS

A total of 104 patients, mean age 58.6 years were enrolled in 13 clinical centres in Russia between 25/9/2020 and 14/11/2020 and randomised to nafamostat plus SOC (n=53) or SOC alone (n=51). There was no significant difference in time to clinical improvement (primary endpoint) between the nafamostat and SOC groups (median 11 [interquartile range (IQR) 9 to 14) vs 11 [IQR 9 to 14] days; Rate Ratio [RR; the ratio for clinical improvement], 1.00; 95% CI, 0.65 to 1.57; p=0.953). In 36 patients with baseline NEWS ≥7, nafamostat was superior to SOC alone in median time to clinical improvement (11 vs 14 days; RR, 2.89; 95% CI, 1.17 to 7.14; p=0.012). Patients receiving nafamostat in this subgroup had a significantly higher recovery rate compared with SOC alone (61.1% (11/18) vs 11.1 % (2/18) by Day 11, p=0.002). The 28-day mortality was 1.9% (1/52) for nafamostat and 8.0% (4/50) for SOC (95% CI, -17.0 to 3.4; p=0.155). No case of COVID-19 related serious adverse events leading to death was recorded in the patients receiving nafamostat.

INTERPRETATION

Our study found no significant difference in time to clinical improvement between the nafamostat and SOC groups, but a shorter median time to clinical improvement in a small group of high-risk COVID-19 patients requiring oxygen treatment. To assess the efficacy further, a larger Phase 3 clinical trial is warranted.

FUNDING

Korea Research Institute of Bioscience and Biotechnology [2020M3A9H5108928] and Chong Kun Dang (CKD) Pharm (Seoul, Korea).

New Trends, Advantages and Disadvantages in Anticoagulation and Coating Methods Used in Extracorporeal Life Support Devices

The use of extracorporeal life support (ECLS) devices has significantly increased in the last decades. Despite medical and technological advancements, a main challenge in the ECLS field remains the complex interaction between the human body, blood, and artificial materials. Indeed, blood exposure to artificial surfaces generates an unbalanced activation of the coagulation cascade, leading to hemorrhagic and thrombotic events. Over time, several anticoagulation and coatings methods have been introduced to address this problem. This narrative review summarizes trends, advantages, and disadvantages of anticoagulation and coating methods used in the ECLS field. Evidence was collected through a PubMed search and reference scanning. A group of experts was convened to openly discuss the retrieved references. Clinical practice in ECLS is still based on the large use of unfractionated heparin and, as an alternative in case of contraindications, nafamostat mesilate, bivalirudin, and argatroban. Other anticoagulation methods are under investigation, but none is about to enter the clinical routine. From an engineering point of view, material modifications have focused on commercially available biomimetic and biopassive surfaces and on the development of endothelialized surfaces. Biocompatible and bio-hybrid materials not requiring combined systemic anticoagulation should be the future goal, but intense efforts are still required to fulfill this purpose.

Targeting the intestinal TMPRSS2 protease to prevent SARS-CoV-2 entry into enterocytes-prospects and challenges

The transmembrane protease serine 2 (TMPRSS2) is a membrane anchored protease that primarily expressed by epithelial cells of respiratory and gastrointestinal systems and has been linked to multiple pathological processes in humans including tumor growth, metastasis and viral infections. Recent studies have shown that TMPRSS2 expressed on cell surface of host cells could play a crucial role in activation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein which facilitates the rapid early entry of the virus into host cells. In addition, direct suppression of TMPRSS2 using small drug inhibitors has been demonstrated to be effective in decreasing SARS-CoV-2 infection in vitro, which presents TMPRSS2 protease as a potential therapeutic strategy for SARS-CoV-2 infection. Recently, SARS-CoV-2 has been shown to be capable of infecting gastrointestinal enterocytes and to provoke gastrointestinal disorders in patients with COVID-19 disease, which is considered as a new transmission route and target organ of SARS-CoV-2. In this review, we highlight the biochemical properties of TMPRSS2 protease and discuss the potential targeting of TMPRSS2 by inhibitors to prevent the SARS-CoV-2 spreading through gastro-intestinal tract system as well as the hurdles that need to be overcome.

A Systematic Literature Review of Packed Red Cell Transfusion Usage in Adult Extracorporeal Membrane Oxygenation

Background: Blood product administration plays a major role in the management of patients treated with extracorporeal membrane oxygenation (ECMO) and may be a contributor to morbidity and mortality. Methods: We performed a systematic review of the published literature to determine the current usage of packed red cell transfusions. Predefined search criteria were used to identify journal articles reporting transfusion practice in ECMO by interrogating EMBASE and Medline databases and following the PRISMA statement. Results: Out of 1579 abstracts screened, articles reporting ECMO usage in a minimum of 10 adult patients were included. Full texts of 331 articles were obtained, and 54 were included in the final analysis. All studies were observational (2 were designed prospectively, and two were multicentre). A total of 3808 patients were reported (range 10–517). Mean exposure to ECMO was 8.2 days (95% confidence interval (CI) 7.0–9.4). A median of 5.6% was not transfused (interquartile range (IQR) 0–11.3%, 19 studies). The mean red cell transfusion per ECMO run was 17.7 units (CI 14.2–21.2, from 52 studies) or 2.60 units per day (CI 1.93–3.27, from 49 studies). The median survival to discharge was 50.8% (IQR 40.0–64.9%). Conclusion: Current evidence on transfusion practice in ECMO is mainly drawn from single-centre observational trials and varies widely. The need for transfusions is highly variable. Confounding factors influencing transfusion practice need to be identified in prospective multicentre studies to mitigate potential harmful effects and generate hypotheses for interventional trials.

Severe COVID-19 Pneumonia in a 30-Year-Old Woman in the 36th Week of Pregnancy Treated with Postpartum Extracorporeal Membrane Oxygenation

Patient: Female, 30-year-old

Final Diagnosis: Severe COVID-19 pneumonia

Symptoms: Dyspena

Medication: —

Clinical Procedure: Extracorporeal membrane oxygenation

Specialty: Critical Care Medicine • Infectious Diseases

COVID-19/SARS-CoV-2 Infection: Lysosomes and Lysosomotropism Implicate New Treatment Strategies and Personal Risks

In line with SARS and MERS, the SARS-CoV-2/COVID-19 pandemic is one of the largest challenges in medicine and health care worldwide. SARS-CoV-2 infection/COVID-19 provides numerous therapeutic targets, each of them promising, but not leading to the success of therapy to date. Neither an antiviral nor an immunomodulatory therapy in patients with SARS-CoV-2 infection/COVID-19 or pre-exposure prophylaxis against SARS-CoV-2 has proved to be effective. In this review, we try to close the gap and point out the likely relationships among lysosomotropism, increasing lysosomal pH, SARS-CoV-2 infection, and disease process, and we deduce an approach for the treatment and prophylaxis of COVID-19, and cytokine release syndrome (CRS)/cytokine storm triggered by bacteria or viruses. Lysosomotropic compounds affect prominent inflammatory messengers (e.g., IL-1B, CCL4, CCL20, and IL-6), cathepsin-L-dependent viral entry of host cells, and products of lysosomal enzymes that promote endothelial stress response in systemic inflammation. As supported by recent clinical data, patients who have already taken lysosomotropic drugs for other pre-existing conditions likely benefit from this treatment in the COVID-19 pandemic. The early administration of a combination of antivirals such as remdesivir and lysosomotropic drugs, such as the antibiotics teicoplanin or dalbavancin, seems to be able to prevent SARS-CoV-2 infection and transition to COVID-19.

Clinical outcomes of extracorporeal membrane oxygenation in acute traumatic lung injury: a retrospective study

Background

Therapeutic extracorporeal membrane oxygenation (ECMO) is a challenging procedure in patients who have experienced severe trauma. Particularly, patients with traumatic lung injury and posttraumatic acute respiratory distress syndrome (ARDS) have a high risk of bleeding during this procedure. This study aimed to determine the safety and feasibility of ECMO in patients with traumatic ARDS.

Methods

We retrospectively reviewed medical records and investigated the clinical outcomes of ECMO in 42 patients with traumatic ARDS, among whom near-drowning (42.9%) was the most frequent cause of injury.

Results

Thirty-four of 42 patients (81%) survived and were discharged after a median hospital stay of 23 days. A multivariate analysis identified a lactate level (odds ratio: 1.493, 95% confidence interval: 1.060–2.103, P = 0.022) and veno-venous (VV) ECMO (odds ratio: 0.075, 95% confidence interval: 0.006–0.901, P = 0.041) as favorable independent predictors of survival in patients with traumatic ARDS who underwent ECMO. The optimal cut off value for pre-ECMO lactate level was 10.5 mmol/L (area under the curve = 0.929, P = 0.001). In Kaplan-Meier analysis, the survival rate at hospital discharge was significant higher among the patients with a pre-ECMO lactate level of 10.5 mmol/L or less compared with patients with pre-ECMO lactate level greater than 10.5 mmol/L (93.8% versus 40.0%, respectively; P = 0.01).

Conclusions

ECMO yielded excellent survival outcomes, particularly in patients with low pre-treatment lactate levels who received VV ECMO. Therefore, ECMO appears safe and highly feasible in a carefully selected population of trauma patients.

Nafamostat mesylate attenuates the pathophysiologic sequelae of neurovascular ischemia

Nafamostat mesylate, an apparent soi-disant panacea of sorts, is widely used to anticoagulate patients undergoing hemodialysis or cardiopulmonary bypass, mitigate the inflammatory response in patients diagnosed with acute pancreatitis, and reverse the coagulopathy of patients experiencing the commonly preterminal disseminated intravascular coagulation in the Far East. The serine protease inhibitor nafamostat mesylate exhibits significant neuroprotective effects in the setting of neurovascular ischemia. Nafamostat mesylate generates neuroprotective effects by attenuating the enzymatic activity of serine proteases, neuroinflammatory signaling cascades, and the endoplasmic reticulum stress responses, downregulating excitotoxic transient receptor membrane channel subfamily 7 cationic currents, modulating the activity of intracellular signal transduction pathways, and supporting neuronal survival (brain-derived neurotrophic factor/TrkB/ERK1/2/CREB, nuclear factor kappa B. The effects collectively reduce neuronal necrosis and apoptosis and prevent ischemia mediated disruption of blood-brain barrier microarchitecture. Investigational clinical applications of these compounds may mitigate ischemic reperfusion injury in patients undergoing cardiac, hepatic, renal, or intestinal transplant, preventing allograft rejection, and treating solid organ malignancies. Neuroprotective effects mediated by nafamostat mesylate support the wise conduct of randomized prospective controlled trials in Western countries to evaluate the clinical utility of this compound.

Fibrinolysis Inhibitors: Potential Drugs for the Treatment and Prevention of Bleeding

Hyperfibrinolytic situations can lead to life-threatening bleeding, especially during cardiac surgery. The approved antifibrinolytic agents such as tranexamic acid, ε-aminocaproic acid, 4-aminomethylbenzoic acid, and aprotinin were developed in the 1960s without the structural insight of their respective targets. Crystal structures of the main antifibrinolytic targets, the lysine binding sites on plasminogen's kringle domains, and plasmin's serine protease domain greatly contributed to the structure-based drug design of novel inhibitor classes. Two series of ligands targeting the lysine binding sites have been recently described, which are more potent than the most-widely used antifibrinolytic agent, tranexamic acid. Furthermore, four types of promising active site inhibitors of plasmin have been developed: tranexamic acid conjugates targeting the S1 pocket and primed sites, substrate-analogue linear homopiperidylalanine-containing 4-amidinobenzylamide derivatives, macrocyclic inhibitors addressing nonprimed binding regions, and bicyclic 14-mer SFTI-1 analogues blocking both, primed and nonprimed binding sites of plasmin. Furthermore, several allosteric plasmin inhibitors based on heparin mimetics have been developed.

Heparin-induced thrombocytopenia complicating extracorporeal membrane oxygenation support: Review of the literature and alternative anticoagulants

Heparin-induced thrombocytopenia (HIT) is a life-threatening prothrombotic, immune-mediated complication of unfractionated heparin and low molecular weight heparin therapy. HIT is characterized by moderate thrombocytopenia 5-10 days after initial heparin exposure, detection of platelet-activating anti-platelet factor 4/heparin antibodies and an increased risk of venous and arterial thrombosis. Extracorporeal membrane oxygenation (ECMO) is a form of mechanical circulatory support used in critically ill patients with respiratory or cardiac failure. Systemic anticoagulation is used to alleviate the thrombotic complications that may occur when blood is exposed to artificial surfaces within the ECMO circuit. Therefore, when HIT complicates patients on ECMO support, it is associated with a high thrombotic morbidity and mortality. The risk for HIT correlates with the accumulative dosage of heparin exposure. In ECMO patients receiving continuous infusion of heparin for circuit patency, the risk for HIT is not neglected and must be thought of in the differential diagnosis of the appropriate clinical and laboratory circumstances. The following article reviews the current knowledge in HIT complicating ECMO patients and the alternative anticoagulation options in the presence of HIT.

Single-center experience of extracorporeal membrane oxygenation mainly anticoagulated with nafamostat mesilate

Background

Bleeding remains the chief concern during extracorporeal membrane oxygenation (ECMO). Recently, several studies proposed nafamostat mesilate (NM) as an alternative anticoagulant to heparin due to reduced bleeding complications and comparable thromboembolic episodes. The aim of this study was to evaluate the clinical outcomes of ECMO anticoagulated mainly with NM.

Methods

This was a retrospective observational case series of patients who were placed on ECMO between January 2011 and December 2017 at Chungnam National University Hospital. The main outcomes were bleeding and thromboembolic episodes.

Results

During the study period, a total of 91 ECMO runs on 87 patients were identified. There were 54 veno-venous runs and 37 veno-arterial runs. Among the 87 patients, 47 (54.0%) patients were successfully weaned and 29 (33.3%) survived to discharge. Most of the runs were anticoagulated with NM (n=68, 74.7%), followed by heparin (n=22, 24.2%) and argatroban (n=1, 1.1%). The mean duration of ECMO support was 11.3±11.1 days. The overall incidence of bleeding was 46.2% (n=42); 26 runs were anticoagulated with NM (26/68, 38.2%) and 16 with heparin (16/22, 72.7%) (P=0.005). The overall incidence of thromboembolic episodes was 12.1% (n=11). In the NM group, the incidence of hyperkalemia requiring any type of intervention was 17.6% (n=12).

Conclusions

In this single center study, NM appears to be associated with fewer bleeding complications during ECMO without increasing the incidence of thromboembolic episodes.

The Antiviral Potential of Host Protease Inhibitors

The replication of numerous pathogenic viruses depends on host proteases, which therefore emerged as potential antiviral drug targets. In some cases, e.g., for influenza viruses, their function during the viral propagation cycle is relatively well understood, where they cleave and activate viral surface glycoproteins. For other viruses, e.g., Ebola virus, the function of host proteases during replication is still not clear. Host proteases may also contribute to the pathogenicity of virus infection by activating proinflammatory cytokines. For some coronaviruses, human proteases can also serve in a nonproteolytical fashion simply as receptors for virus entry. However, blocking of such protein-protein contacts is challenging, because receptor surfaces are often flat and difficult to address with small molecules. In contrast, many proteases possess well-defined binding pockets. Therefore, they can be considered as well-druggable targets, especially, if they are extracellularly active. The number of their experimental crystal structures is steadily increasing, which is an important prerequisite for a rational structure-based inhibitor design using computational chemistry tools in combination with classical medicinal chemistry approaches. Moreover, host proteases can be considered as stable targets, and their inhibition should prevent rapid resistance developments, which is often observed when addressing viral proteins. Otherwise, the inhibition of host proteases can also affect normal physiological processes leading to a higher probability of side effects and a narrow therapeutic window. Therefore, they should be preferably used in combination therapies with additional antiviral drugs. This strategy should provide a stronger antiviral efficacy, allow to use lower drug doses, and minimize side effects. Despite numerous experimental findings on their antiviral activity, no small-molecule inhibitors of host proteases have been approved for the treatment of virus infections, so far.

Validation of Nafamostat Mesilate as an Anticoagulant in Extracorporeal Membrane Oxygenation: A Large-Animal Experiment

Background

Unfractionated heparin is commonly used for anticoagulation in extracorporeal membrane oxygenation (ECMO). Several studies have shown that nafamostat mesilate (NM) has comparable clinical outcomes to unfractionated heparin. This study compared anticoagulation with NM and heparin in a large-animal model.

Methods

Beagle dogs (n=8; weight, 6.5-9 kg) were placed on venovenous ECMO. Blood samples were taken every hour and the following parameters were compared: hemoglobin level, activated partial thromboplastin time (aPTT), thromboelastography (TEG) data, platelet function, and inflammatory cytokine levels.

Results

In both groups, the aPTT was longer than the baseline value. Although the aPTT in the NM group was shorter than in the heparin group, the TEG parameters were similar between the 2 groups. Hemoglobin levels decreased in both groups, but the decrease was less with NM than with heparin (p=0.049). Interleukin (IL)-1β levels significantly decreased in the NM group (p=0.01), but there was no difference in the levels of tumor necrosis factor alpha or IL-10 between the 2 groups.

Conclusion

NM showed a similar anticoagulant effect to that of unfractionated heparin, with fewer bleeding complications. NM also had anti-inflammatory properties during ECMO. Based on this preclinical study, NM may be a good alternative candidate for anticoagulation in ECMO.

Intraoperative Venovenous Extracorporeal Membrane Oxygenation During Thoracic Surgery That Requires 1-Lung Ventilation: A Case Report

We report 3 cases of thoracic surgery that required 1-lung ventilation where venovenous extracorporeal membrane oxygenation was prophylactically used because severe hypoxemia and ventilatory failure were anticipated intraoperatively. The surgery was successfully completed in all 3 cases. However, we had to withdraw the extracorporeal membrane oxygenation support in 1 case because of uncontrollable hemorrhage. Venovenous extracorporeal membrane oxygenation is a feasible option when severe hypoxemia and/or ventilatory failure is anticipated during 1-lung ventilation.

Optimization of Substrate-Analogue Furin Inhibitors

The proprotein convertase furin is a potential target for drug design, especially for the inhibition of furin-dependent virus replication. All effective synthetic furin inhibitors identified thus far are multibasic compounds; the highest potency was found for our previously developed inhibitor 4-(guanidinomethyl)phenylacetyl-Arg-Tle-Arg-4-amidinobenzylamide (MI-1148). An initial study in mice revealed a narrow therapeutic range for this tetrabasic compound, while significantly reduced toxicity was observed for some tribasic analogues. This suggests that the toxicity depends at least to some extent on the overall multibasic character of this inhibitor. Therefore, in a first approach, the C-terminal benzamidine of MI-1148 was replaced by less basic P1 residues. Despite decreased potency, a few compounds still inhibit furin in the low nanomolar range, but display negligible efficacy in cells. In a second approach, the P2 arginine was replaced by lysine; compared to MI-1148, this furin inhibitor has slightly decreased potency, but exhibits similar antiviral activity against West Nile and Dengue virus in cell culture and decreased toxicity in mice. These results provide a promising starting point for the development of efficacious and well-tolerated furin inhibitors.

Anticoagulation Therapy during Extracorporeal Membrane Oxygenator Support in Pediatric Patients

Extracorporeal membrane oxygenation (ECMO) is a salvage therapy for critically ill patients. Although ECMO is becoming more common, hemorrhagic and thromboembolic complications remain the major causes of death in patients undergoing ECMO treatments. These complications commence upon blood contact with artificial surfaces of the circuit, blood pump, and oxygenator system. Therefore, anticoagulation therapy is required in most cases to prevent these problems. Anticoagulation is more complicated in pediatric patients than in adults, and the foreign surface of ECMO only increases the complexity of systemic anticoagulation. In this review, we discuss the pathophysiology of coagulation, anticoagulants, and monitoring tools in pediatric patients receiving ECMO.

Advanced Age as a Predictor of Survival and Weaning in Venoarterial Extracorporeal Oxygenation: A Retrospective Observational Study

Background. In most reports on ECMO treatment, advanced age is classified as a contraindication to VA ECMO. We attempted to investigate whether advanced age would be a main risk factor deciding VA ECMO application and performing VA ECMO support. We determined whether advanced age should be regarded as an absolute or relative contraindication to VA ECMO and could affect weaning and survival rates of VA ECMO patients. Methods. VA ECMO was performed on 135 adult patients with primary cardiogenic shock between January 2010 and December 2014. Successful weaning was defined as weaning from ECMO followed by survival for more than 48 hours. Results. Among the 135 patients, 35 survived and were discharged uneventfully, and the remaining 100 did not survive. There were significant differences in survival between age groups, and older age showed a lower survival rate with statistical significance (P = .01). By multivariate logistic regression analysis, age was not significantly associated with in-hospital mortality (P = .83) and was not significantly associated with VA ECMO weaning (P = .11). Conclusions. Advanced age is an undeniable risk factor for VA ECMO; however, patients of advanced age should not be excluded from the chance of recovery after VA ECMO treatment.

Extracorporeal Membrane Oxygenation Support in Trauma Versus Nontrauma Patients with Noninfectious Acute Respiratory Failure

The utility of extracorporeal membrane oxygenation (ECMO) in patients with acute respiratory distress syndrome (ARDS) of noninfectious origin remains unclear. Data on patients with ARDS of noninfectious origin who underwent ECMO were reviewed retrospectively. We compared the pre-ECMO characteristics and hospital outcomes of patients with traumatic and nontraumatic ARDS. In total, 23 patients (trauma, n = 9; nontrauma, n = 14) were included in the study. The mean patient age was 42 years, there were three females, and the mean pre-ECMO Simplified Acute Physiologic Score (SAPS) II was 60.0 (49.0-71.0). The hemoglobin level was lower and the prothrombin time (PT) more prolonged, prior to initiation of ECMO, in traumatic compared with nontraumatic ARDS patients. During the first 48 h of ECMO support, the coagulation parameters did not differ between the two groups, but the platelet counts, PT, and activated partial thromboplastin time indicated that coagulopathy was developing in all patients. The hospital and 28-day mortality rates were 21.7 and 13.0%, respectively, and serious neurological outcomes (cerebral performance category [CPC] of three points or more) developed in 26.1% of all patients; however, the extent of such outcomes did not differ between traumatic and nontraumatic ARDS patients. Upon multivariate analysis, the pre-ECMO SAPS II tended to be associated with composite events (i.e., hospital death and/or a CPC of three points or more) (P = 0.051). Additionally, a history of hypertension and an elevated pre-ECMO SAPS II were significant risk factors for serious neurological outcomes among hospital survivors (n = 18). In conclusion, ECMO support can be associated with favorable outcomes in patients with ARDS of noninfectious origin, irrespective of whether the ARDS is associated with trauma. The pre-ECMO SAPS II and a history of hypertension may be independent risk factors for poor outcomes.

Venovenous Extracorporeal Membrane Oxygenation in Intractable Pulmonary Insufficiency: Practical Issues and Future Directions

Venovenous extracorporeal membrane oxygenation (vv-ECMO) is a highly invasive method for organ support that is gaining in popularity due to recent technical advances and its successful application in the recent H1N1 epidemic. Although running a vv-ECMO program is potentially feasible for many hospitals, there are many theoretical concepts and practical issues that merit attention and require expertise. In this review, we focus on indications for vv-ECMO, components of the circuit, and management of patients on vv-ECMO. Concepts regarding oxygenation and decarboxylation and how they can be influenced are discussed. Day-to-day management, weaning, and most frequent complications are covered in light of the recent literature.

Nafamostat Mesilate as a Regional Anticoagulant in Patients with Bleeding Complications during Extracorporeal Membrane Oxygenation

Purpose

Anticoagulation is mandatory for extracorporeal membrane oxygenation (ECMO), but systemic heparinization, which has been most widely used as an anticoagulant, has been associated with bleeding complications. The present study reviewed the usefulness and safety of nafamostat mesilate as a regional anticoagulant in patients with bleeding complication during ECMO.

Methods

We retrospectively reviewed the record of 13 cases. The nafamostat mesilate dose was regulated to maintain the activated clotting time (ACT) or activated partial thromboplastin time (aPTT) values within an adequate range at the ECMO reinfusion route. ACT or aPTT values in blood samples from the ECMO circuit and from the patients were measured simultaneously and consecutively.

Results

We measured the ACT value in 6 cases and aPTT in 7 cases. The bleeding complications were treated in 11 cases. When we compared the difference in 2 anticoagulation values (ACT and aPTT) between the 2 blood samples, one taken from ECMO and the other from patients, mean anticoagulation values of blood from patients were lower than those from ECMO circuit in 11 cases. With respect to the type of ECMO reinfusion mode, the difference was significant only in veno-arterial mode ECMO group (p<0.001).

Conclusions

Nafamostat mesilate, with which we can reduce anticoagulation values of patient to a safe level without losing the ECMO anticoagulation values is expected to be useful as a regional anticoagulant in patients with bleeding complications or a high risk of bleeding during ECMO.

The pre-ECMO simplified acute physiology score II as a predictor for mortality in patients with initiation ECMO support at the emergency department for acute circulatory and/or respiratory failure: a retrospective study

Background

In the emergency department (ED), extracorporeal membrane oxygenation (ECMO) can be used as a rescue treatment modality for patients with refractory circulatory and/or respiratory failure. Serious consideration must be given to the indication, and the PRESERVE and RESP scores for mortality have been investigated. However these scores were validated to predict survival in patients who received mainly veno-venous (VV) ECMO in the intensive care unit. The aim of the present study was to investigate the factors that predicted the outcomes for patients who received mixed mode (veno-arterial [VA] and VV) ECMO support in the ED.

Methods

This single center retrospective study included 65 patients who received ECMO support at the ED for circulatory or respiratory failure between January 2009 and December 2013. Pre-ECMO SAPS II and other variables were evaluated and compared for predicting mortality.

Results

Fifty-four percent of patients received ECMO-cardiopulmonary resuscitation (E-CPR), 31 % received VA and V-AV ECMO, and 15 % received VV ECMO. The 28-day and 60-month mortality rates were 52 % and 63 %. In the multivariate analysis, only the pre-ECMO Simplified Acute Physiology Score II (SAPS II) (odd ratio: 1.189, 95 % confidence interval: 1.032–1.370, p = 0.016) could predict the 28-day mortality. The area under the receiver operating characteristic curve and the optimal cutoff value for pre-ECMO SAPS II in predicting 28-day mortality was 0.852 (95 % CI: 0.753–0.951, p < 0.001) and 80 (sensitivity of 97.1 % and specificity of 71.0 %), respectively. Validation of the 80 cutoff value revealed a statistically significant difference for the 28-day and 60-month mortality rates in the overall, E-CPR, and VA groups (28-day: p < 0.001, p = 0.004, p = 0.005; 60-month: p < 0.001, p = 0.004, p = 0.020). In the Kaplan-Meier analysis, the 28-day and 60-month survival rates were lower among the patients with a pre-ECMO SAPS II of ≤80, compared to those with a score of >80 (both, p < 0.001).

Conclusion

The pre-ECMO SAPS II could be helpful for identifying patients with refractory acute circulatory and/or respiratory failure who will respond to ECMO support in the ED.

Use of a fixed, body weight-unadjusted loading dose of unfractionated heparin for extracorporeal cardiopulmonary resuscitation

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) is being used increasingly in the emergency and critical care field in Japan. A major complication of ECPR is bleeding; however, the optimal initial heparin dose and activated coagulation time (ACT) remain unknown. The aim of this study was to assess the appropriateness of our initial anticoagulation protocol.

Methods

We retrospectively evaluated the initial heparin dose, ACT value, and incidence of bleeding and thrombotic complications in post-cardiopulmonary arrest patients who received a fixed, body weight-unadjusted loading dose of unfractionated heparin (3000 U) prior to veno-arterial extracorporeal membrane oxygenator (ECMO) between February 2011 and November 2013 at Mie University Hospital, Japan.

Results

ACT was evaluated within 3 h of initiation of 32 consecutive ECPR patients. The mean heparin dose per body weight was 53.6 U/kg and the mean ACT was 231.3 s. In 17 patients, ACT exceeded 200 s. Three patients experienced fatal bleeding in the chest wall within 24 h of receiving ECMO. The mean heparin dose per kilogram body weight, mean initial ACT, and mean duration of cardiopulmonary resuscitation (CPR) did not statistically differ between the patients who experienced fatal bleeding and those who did not.

Conclusions

Fixed-dose heparin of 3000-U bolus resulted in a mean heparin dose per kilogram body weight of 53.6 U/kg and an ACT of 231.3 s and experienced 3 out of 32 fatal bleedings. Further researches are warranted to optimize anticoagulation protocol for ECPR patients.

Predictors of survival following extracorporeal cardiopulmonary resuscitation in patients with acute myocardial infarction-complicated refractory cardiac arrest in the emergency department: a retrospective study

Background

This study aimed to identify the determinant factors for clinical outcomes and survival rates of patients with cardiac arrest (CA) concurrent with acute myocardial infarction (AMI) who underwent extracorporeal cardiopulmonary resuscitation (ECPR) using extracorporeal membrane oxygenation (ECMO).

Methods

We retrospectively evaluated 37 patients admitted to our emergency department between January 2006 and August 2012 for AMI-induced CA treated with ECPR during ongoing continuous chest compressions.

Results

Mean patient age was 61.4 ± 11.3 years, and 27 patients (73%) were men. Mean CPR time was 50.8 ± 35.4 min. Door-to-ECMO and door-to-balloon times were 84.4 ± 55.3 and 98.4 ± 56.8 min, respectively. Mean ECMO time was 106.4 ± 84.7 h; nine (24%) patients died within 24 h after ECMO initiation. Twelve (32%) patients were weaned off ECMO, seven (19%) of whom survived >30 days after ECMO removal; all except one had Cerebral Performance Category Grade 1. Of the patients who survived, 5 of them were able to be discharged. In multivariate analysis, statistical significance was only observed in door-to-ECMO time ≤60 min (OR, 6.0; 95% CI, 1,177–852.025; p = 0.033).

Conclusion

We conclude that ECMO insertion within 60 min of the arrival of patients with AMI and CA at the ED appears to be a good option for maintaining myocardial and systemic perfusion, thereby increasing the survival rate of these patients.

Extracorporeal membrane oxygenation in near-drowning patients with cardiac or pulmonary failure

Background

The aim of this study was to determine the early outcomes of using extracorporeal membrane oxygenation (ECMO) in near-drowning patients with cardiac or pulmonary failure.

Methods

This study was based on data from 9 patients including 2 children (mean age 33; 8 males, 1 female) who received ECMO after near-drowning between 2008 and 2013. Veno-arterial or veno-arteriovenous ECMO was used in 2 patients with sustained cardiac arrest and veno-venous ECMO was used in 7 patients with severe acute respiratory distress syndrome (ARDS). The means of the partial arterial oxygen pressure (PaO₂), Murray score, sequential organ failure assessment (SOFA) score, and simplified acute physiology score II (SAPS-II) prior to ECMO were 59.7 ± 9.9 mmHg on 100% oxygen, 3.5 ± 0.6, 11.4 ± 1.9, and 73.0 ± 9.2, respectively.

Results

The PaO₂ mean improved to 182 ± 152 mmHg within 2 h post-ECMO. The mean of SOFA score and SAPS-II decreased significantly to 8.6 ± 3.2 (p = 0.013) and 46.4 ± 5.1 (p = 0.008), respectively, at 24 h post-ECMO with mean flow rate of 3.9 ± 0.8 l/min. ECMO was weaned at a mean duration of 188 (range, 43–672) h in all patients. Seven patients were discharged home without neurological sequelae, while 2 patients who had hypoxic brain damage died after further referral. The overall survival with favourable neurological outcomes at 3 months was 77.8%. There were no complications related to ECMO.

Conclusions

ECMO was safe and effective for patients with ongoing cardiac arrest or ARDS after a near-drowning incident and can be used as a resuscitative strategy in near-drowning patients with cardiac or pulmonary failure resistant to conventional ventilator therapy.

Nafamostat mesilate: can it be used as a conduit preserving agent in coronary artery bypass surgery?

Background

Graft vessel preservation solution in coronary artery bypass surgery is used to maintain the graft conduit in optimal condition during the perioperative period. Nafamostat mesilate (NM) has anticoagulation and anti-inflammatory properties. Therefore, we investigated NM as a conduit preservative agent and compared it to papaverine.

Methods

Sprague-Dawley (SD) rat thoracic aortas were examined for their contraction-relaxation ability using phenylephrine (PE) and acetylcholine (ACh) following preincubation with papaverine and NM in standard classical organ baths. Human umbilical vein endothelial cells (HUVECs) were cultured to check for the endothelial cell viability. Histopathological examination and terminal deoxynucleotidyl transferase dUTP nick end labeling assay were performed on the thoracic aortas of SD rats.

Results

The anti-contraction effects of papaverine were superior to those of NM at PE (p<0.05). The relaxation effect of NM on ACh-induced vasodilatation was not statistically different from that of papaverine. Viability assays using HUVECs showed endothelial cell survival rates of >90% in various concentrations of both NM and papaverine. A histopathological study showed a protective effect against necrosis and apoptosis (p<0.05) in the NM group.

Conclusion

NM exhibited good vascular relaxation and a reasonable anti-vasocontraction effect with a better cell protecting effect than papaverine; therefore, we concluded that NM is a good potential conduit preserving agent.

Extracorporeal membrane oxygenation for acute life-threatening neurogenic pulmonary edema following rupture of an intracranial aneurysm

Neurogenic pulmonary edema (NPE) leading to cardiopulmonary dysfunction is a potentially life-threatening complication in patients with central nervous system lesions. This case report describes a 28-yr woman with life-threatening fulminant NPE, which was refractory to conventional respiratory treatment, following the rupture of an aneurysm. She was treated successfully with extracorporeal membrane oxygenation (ECMO), although ECMO therapy is generally contraindicated in neurological injuries such as brain trauma and diseases that are likely to require surgical intervention. The success of this treatment suggests that ECMO therapy should not be withheld from patients with life-threatening fulminant NPE after subarachnoid hemorrhage.

Experiences of tracheal procedure assisted by extracorporeal membrane oxygenator

We report on the application of a venovenous type extracorporeal membrane oxygenator (ECMO) in high-risk tracheal procedures in six cases consisting of five patients with tracheal stenosis. An ECMO should be helpful for preventing respiratory emergency during a tracheal procedure.