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Background: Irreversible electroporation (IRE) is a novel tumour ablation technique involving repetitive application of electrical energy around a tumour. The use of pulsed electrical gradients carries a risk of cardiac arrhythmias, severe muscle contractions, and seizures. We aimed to identify IRE-related risks and the appropriate precautions for anaesthetic management., Methods: All patients who were treated with IRE were prospectively included. Exclusion criteria were arrhythmias, congestive heart failure, active coronary artery disease, and epilepsy. All procedures were performed under general anaesthesia with complete muscle relaxation during ECG-synchronized pulsing. Adverse events, cardiovascular effects, blood samples, cerebral activity, and post-procedural pain were analysed., Results: Twenty-eight patients underwent 30 IRE sessions for tumours in the liver, pancreas, kidney, and lesser pelvis. No major adverse events occurred during IRE. Median systolic and diastolic blood pressure increased by 44 mm Hg (range -7 to 108 mm Hg) and 19 mm Hg (range 1-50 mm Hg), respectively. Two transient minor cardiac arrhythmias without haemodynamic consequences were observed. Muscle contractions were mild and IRE caused no reactive brain activity on a simplified EEG. Pain in the first 24 h after percutaneous IRE was generally mild, but higher pain scores were reported after pancreatic treatment (mean VAS score 3; range 0-9)., Conclusions: Side-effects during IRE on tumours in the liver, pancreas, kidney, and lesser pelvis seem mild and manageable when current recommendations for anaesthesia management, including deep muscle relaxation and ECG synchronized pulsing, are followed. Electrical pulses do not seem to cause reactive cerebral activity and evidence for pre-existing atrial fibrillation as an absolute contra-indication for IRE is questionable., (© The Author 2014. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objectives: Irreversible electroporation (IRE) is a new ablation technique that relies on high-voltage electrical pulses. This clinical study evaluates the pathological response of colorectal liver metastases (CRLM) treated with IRE and the clinical safety and feasibility., Methods: Ten patients with resectable CRLM were included. During laparotomy, the metastases were treated with IRE and resected 60 min later. Safety and feasibility were assessed based on adverse events, laboratory values, technical success and intra-operative ultrasound findings. Tissue response was assessed using triphenyl tetrazolium chloride (TTC) vitality staining and (immuno)histochemical stainings (HE, complement-3d and caspase-3)., Results: Ten lesions with a mean diameter of 2.4 cm were successfully electroporated and resected, on average, 84 min later (range 51-153 min). One minor transient cardiac arrhythmia occurred during IRE. Ultrasound showed a sharply demarcated hypoechoic ablation zone around the tumour. TTC showed avitality of all lesions, covering the complete tumour in 8/10 lesions. Although immunohistochemistry proved heterogeneous and difficult to interpret within the tumours, it confirmed irreversible cell damage in the tumour-free margin of all specimens., Conclusions: This ablate-and-resect study demonstrated avitality caused by IRE of CRLM in humans. Further characterisation of tissue- and tumour-specific electrical properties is warranted to improve ablation protocols for maximised tissue ablation., Key Points: • Irreversible electroporation induces cell death in colorectal liver metastases within 1 h. • The ablation zone shows a sharp demarcation between avital and vital tissue. • Apoptosis is involved in cell death of colorectal liver metastases after IRE. • Effects of IRE can be monitored real-time using intraoperative ultrasound. • Local electrical heterogeneities of tumour tissue may require tumour-specific ablation protocols.

Irreversible electroporation (IRE) is a new, non-thermal image-guided tumour ablation technique. The repeated application of high-voltage electrical pulses causes pores to form in the cell membrane, so that cells lose their homeostatic properties, and die. The advantage of IRE over other local ablation techniques is that IRE selectively destroys cells, whilst the surrounding extracellular matrix structures remain intact. Therefore, the anatomic framework that gives vulnerable structures such as bile ducts, blood vessels, ureters and nerves their shape and strength is preserved during IRE, which allows for safe ablation of tumours near these vulnerable structures. Both in the Netherlands and worldwide, various clinical studies are being run on the safety and efficacy of IRE for centrally located hepatic and pancreatic tumours, which are unsuitable for the current local therapies (surgical resection, irradiation or thermal ablation) due to their anatomic location. Although the long-term results are as yet unknown, the future of IRE appears promising. IRE may prove a valuable tool to add in the multidisciplinary treatment of cancer.