Efficacy and Safety of Percutaneous Argon-Helium Cryoablation for Hepatocellular Carcinoma Abutting the Diaphragm.

PURPOSE: To evaluate the efficacy and safety of percutaneous argon-helium cryoablation (CA) for hepatocellular carcinoma (HCC) abutting the diaphragm (<5 mm). MATERIALS AND METHODS: A total of 61 consecutive patients (50 men, 11 women; mean age, 56.3 ± 12.1 years old; range, 32-83 years) with 74 HCC tumors (mean size, 3.3 ± 1.7 cm; range, 0.8-7 cm) who were treated with percutaneous argon-helium CA were enrolled in this retrospective study. Adverse events were evaluated according to Common Terminology Criteria for Adverse Events, version 5.0. Local tumor progression (LTP) and overall survival (OS) were analyzed using the Kaplan-Meier method and the log-rank test. The risk factors associated with OS and LTP were evaluated using univariate and multivariate Cox regression analysis. RESULTS: No periprocedural (30-day) deaths occurred. A total of 29 intrathoracic adverse events occurred in 24 of the 61 patients. Major adverse events were reported in 5 patients (pleural effusion requiring catheter drainage in 4 patients and pneumothorax requiring catheter placement in 1 patient). Median follow-up was 18.7 months (range, 2.3-60.0 months). Median time to LTP after CA was 20.9 months (interquartile range [IQR], 14.1-30.6 months). Median times of OS after CA and diagnosis were 27.3 months (IQR, 15.1-45.1 months) and 40.9 months (interquartile range, 24.8-68.6 months), respectively. Independent prognostic factors for OS included tumor location (left lobe vs right lobe; hazard ratio [HR], 2.031; 95% confidence interval [CI], 1.062-3.885; P = .032) and number of intrahepatic tumors (solitary vs multifocal; HR, 2.684; 95% CI, 1.322-5.447; P = .006). Independent prognostic factors for LTP included age (HR, 0.931; 95% CI, 0.900-0.963; P  < .001), guidance modality (ultrasound vs computed tomography and US; HR, 6.156 95% CI, 1.862-20.348; P  =   .003) and origin of liver disease. CONCLUSIONS: Percutaneous argon-helium CA is safe for the treatment of HCC abutting the diaphragm, with acceptable LTP and OS.

Harmless effects of argon plasma on caudal fin regeneration and embryogenesis of zebrafish: novel biological approaches for safe medical applications of bioplasma.

The argon plasma jet (Ar-PJ) is widely used in medical fields such as dermatology and dentistry, and it is considered a promising tool for cancer therapy. However, the in vivo effects of Ar-PJ for medical uses have not yet been investigated, and there are no biological tools to determine the appropriate clinical dosages of Ar-PJ. In this study, we used the caudal fin and embryo of zebrafish as novel in vivo tools to evaluate the biosafety of Ar-PJ. Typically, Ar-PJ is known to induce cell death in two-dimensional (2D) cell culture systems. By contrast, no detrimental effects of Ar-PJ were shown in our 3D zebrafish systems composed of 2D cells. The Ar-PJ-treated caudal fins grew by an average length of 0.7 mm, similar to the length of the normally regenerating fins. Remarkably, Ar-PJ did not affect the expression patterns of Wnt8a and ß-Catenin, which play important roles in fin regeneration. In the embryo system, 85% of the Ar-PJ-treated embryos hatched, and the lateral length of these embryos was ~3.3 mm, which are equivalent to the lengths of normal embryos. In particular, vasculogenesis, which is the main cellular process during tissue regeneration and embryogenesis, occurred normally under the Ar-PJ dose used in this study. Therefore, our biosafety evaluation tools that use living model systems can be used to provide an experimental guideline to determine the clinically safe dosage of Ar-PJ.

One Year Follow-Up Risk Assessment in SKH-1 Mice and Wounds Treated with an Argon Plasma Jet.

Multiple evidence in animal models and in humans suggest a beneficial role of cold physical plasma in wound treatment. Yet, risk assessment studies are important to further foster therapeutic advancement and acceptance of cold plasma in clinics. Accordingly, we investigated the longterm side effects of repetitive plasma treatment over 14 consecutive days in a rodent full-thickness ear wound model. Subsequently, animals were housed for 350 days and sacrificed thereafter. In blood, systemic changes of the proinflammatory cytokines interleukin 1ß and tumor necrosis factor α were absent. Similarly, tumor marker levels of α-fetoprotein and calcitonin remained unchanged. Using quantitative PCR, the expression levels of several cytokines and tumor markers in liver, lung, and skin were found to be similar in the control and treatment group as well. Likewise, histological and immunohistochemical analysis failed to detect abnormal morphological changes and the presence of tumor markers such as carcinoembryonic antigen, α-fetoprotein, or the neighbor of Punc11. Absence of neoplastic lesions was confirmed by non-invasive imaging methods such as anatomical magnetic resonance imaging and positron emission tomography-computed tomography. Our results suggest that the beneficial effects of cold plasma in wound healing come without apparent side effects including tumor formation or chronic inflammation.

Non-thermal dielectric-barrier discharge plasma damages human keratinocytes by inducing oxidative stress.

The aim of this study was to identify the mechanisms through which dielectric-barrier discharge plasma damages human keratinocytes (HaCaT cells) through the induction of oxidative stress. For this purpose, the cells were exposed to surface dielectric-barrier discharge plasma in 70% oxygen and 30% argon. We noted that cell viability was decreased following exposure of the cells to plasma in a time-dependent manner, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The levels of intracellular reactive oxygen species (ROS) were determined using 2',7'-dichlorodihydrofluorescein diacetate and dihydroethidium was used to monitor superoxide anion production. Plasma induced the generation of ROS, including superoxide anions, hydrogen peroxide and hydroxyl radicals. N-acetyl cysteine, which is an antioxidant, prevented the decrease in cell viability caused by exposure to plasma. ROS generated by exposure to plasma resulted in damage to various cellular components, including lipid membrane peroxidation, DNA breaks and protein carbonylation, which was detected by measuring the levels of 8-isoprostane and diphenyl-1-pyrenylphosphine assay, comet assay and protein carbonyl formation. These results suggest that plasma exerts cytotoxic effects by causing oxidative stress-induced damage to cellular components.

Case report of fatal complication in prostatic cryotherapy. First reported death due to argon gas emboli.

We present the first reported fatality from argon gas emboli during prostate cryosurgery. The decedent underwent cryotherapy for prostate carcinoma using cryoablation probes which were cooled with argon and nitrous oxide and warmed with helium. Minutes into the procedure he experienced sudden cardiovascular collapse and could not be resuscitated. Postmortem examination was performed at the request of family and healthcare providers. Collection of tissues and blood samples had to be conducted carefully to capture suspected noble gases,argon, and helium. Specimens were submitted to Saint Louis University Forensic Toxicology Laboratory for toxicological examination and for evaluation of the composition of the gas retrieved from the vascular system.Gas chromatography mass spectrometric analyses confirmed argon in blood, brain, liver, and gas retrieved from the aorta. These samples had significant argon compared with room air also sent for comparison. The manner of death was accident. To date, there have been no intraoperative surgical fatalities reported from prostatic cryotherapy. We report such an unfortunate death to raise awareness in the medical community. We also describe how to collect and handle blood and tissue samples to submit for toxicological analysis in cases of volatile gas emboli.

The concomitant cryosurgical Cox-Maze procedure using Argon based cryoprobes: 12 month results.

AIM: The cut and sew Cox-Maze III procedure has proven to be extremely effective in curing atrial fibrillation. Due to the relative complexity various procedures were developed to apply ablative lesions to treat atrial fibrillation using different energy sources. In this report we present data related to our experience with Argon based cryoablation system in patients having first time concomitant CryoCox-Maze III procedure and other cardiac surgical procedures. METHODS: This is a prospective study where all patients undergoing the Cox maze procedure are entered into our unique maze registry and are followed at 3, 6, 12, 18, 24 months and yearly thereafter. Health related quality of life (SF-12) and atrial fibrillation frequency and severity of symptoms were obtained preoperatively and at follow up. Rhythm was verified by EKG and 24 hour holter. The Heart Rhythm Society definition of failure (any monitored incident of an atrial arrhythmia >30 seconds) was used to compute the rate of return to sinus rhythm. The ablative technique employed was argon based crytothermia using only 1 to 2 atriotomies. RESULTS: The total number of patients operated by multiple surgeons was 124 with 17% through a right minithoracotomy. The operative mortality (<2%) and perioperative stroke rate (<1%) were very low. At 12 months 87% of the patients were in sinus rhythm and off class I and III antriarrhythmic drugs. There was a clear difference in success rate depending on surgeon's total experience. Quality of life and severity of symptoms were improved significantly. CONCLUSION: The one year results of the CryoCox-Maze III procedure when performed concomitantly with another cardiac surgical procedure demonstrate reasonable safety and efficacy. However, operator experience may be related to better outcome. The ablation of atrial fibrillation may be associated with improved quality of life and symptoms relief.

Argon gas embolism in the application of laparoscopic microwave coagulation therapy.

BACKGROUND: A major concern in the use of the argon beam coagulator system is the potential risk of argon gas embolism. METHODS: Seven cases with argon gas embolism in the English literature were reviewed along with the current case. The latter case was a 77-year-old female having laparoscopic hepatectomy after application of the microwave coagulation system on the cutting planes. RESULTS: Immediately following shots of an argon beam to control local bleeding at the needle hole in the liver caused by microwave coagulation, the end-tidal carbon disappeared, followed by cardiovascular collapse. After 18 min of cardiovascular resuscitation, the tumors were resected under laparotomy. CONCLUSIONS: After reviewing the cases, pneumoperitoneum (57.1%), hepatic needle punctures (42.8%) and direct application of the argon beam to the liver (28.6%) can be considered as risky processes in such events. Caution is necessary in the use of an argon beam in liver surgery to avoid life-threatening gas embolism.

Prospective evaluation of a new high-power argon plasma coagulation system (hp-APC) in therapeutic gastrointestinal endoscopy.

OBJECTIVE: The aim of this study was to prospectively evaluate a new high-power argon plasma coagulation system (hp-APC) in therapeutic gastrointestinal (GI) endoscopy. MATERIAL AND METHODS: From February to June 2005, 216 patients (167 M (77.3%), mean age 66 years) underwent treatment with hp-APC in a total of 275 sessions. Main indications were additive ablation therapy in Barrett's esophagus, palliative treatment of esophageal cancer, gastric polyps/carcinomas, angiodysplasias, Zenker's diverticula, and duodenal adenomas. The new hp-APC device (VIO 300 D with APC 2) was used (15-120 W) in upper GI endoscopy, push-enteroscopy, and double-balloon enteroscopy. RESULTS: The mean number of treatment sessions required was 1.7 (1-5). For palliative tumor ablation in the esophagus, the number of sessions was 2.3 (1-5). Minor complications (pain, dysphagia, neuromuscular irritation, asymptomatic gas accumulation in the intestinal wall) were observed in 29/216 patients (13.4%). Major complications (perforation, stenosis occurred) in 2 patients (0.9%). CONCLUSIONS: Hp-APC appears to be safe and effective in the treatment of various GI condition using different types of endoscopes including double-balloon enteroscopy. Because of the low number of treatment sessions required, hp-APC could be used as an alternative to Nd:YAG laser treatment in tumor debulking.

Utilização do laser de argônio na remoção de sutura corneana / Use of argon laser in corneal suture removal

OBJETIVO: Descrever a técnica da retirada de sutura em córnea clara, evitando-se o contato da parte externa do fio com o meio intra-ocular e avaliar se esse procedimento evitaria infecções. MÉTODOS: Foi realizado estudo retrospectivo de 1.233 casos de retirada de sutura de mononylon 10.0 em córnea clara, utilizando-se laser de argônio para cortar o fio, no qual se avaliou a incidência de infecções. RESULTADOS: Em 1.071 olhos, um tiro foi suficiente para cortar o ponto. Em 162 olhos, o tiro do laser atingiu a parte epitelial da sutura, sendo necessários disparos extras para cortar a parte intra-estromal e, assim, retirá-la sem que a parte externa do fio passasse pelo interior da córnea. Não ocorreram complicações após a retirada da sutura. CONCLUSÕES: A técnica utilizada mostrou-se eficaz na remoção das suturas e possivelmente apresenta risco menor de infecção, uma vez que a parte do fio sobrejacente ao epitélio não entra em contato com as camadas mais internas da córnea, nem com a câmara anterior, não tendo sido observado nenhum caso de infecção nesta pesquisa.

Argon plasma coagulation for treatment of watermelon stomach.

BACKGROUND AND STUDY AIMS: Watermelon stomach or gastric antral vascular ectasia (GAVE) is a rare but well-recognized cause of gastrointestinal blood loss, which typically affects elderly women. Historically patients were treated with antrectomy but this has been largely replaced by endoscopic therapy such as Nd:YAG laser. Argon plasma coagulation (APC) is a new noncontact electocoagulation technique which has several theoretical advantages over laser. The objective of this study was to assess the efficacy of APC in treating GAVE. PATIENTS AND METHODS: We retrospectively reviewed the case-records of five patients (four women, one man) with iron deficiency anaemia or gastrointestinal blood loss due to GAVE who were treated with APC and for whom a follow-up of more than 12 months was available. Four patients were transfusion-dependent. Their mean age was 71 years (range 58 - 83). The mode of presentation, number of treatment sessions, response to therapy and recurrence (if any) were recorded. RESULTS: A mean of 2.6 treatment sessions per patient were required. All patients had an endoscopically observed response to therapy and all patients had a sustained rise in hemoglobin level after treatment. Transfusion dependence ceased in all patients. After a mean follow-up of 20 months GAVE recurred in two patients (40 %). Both patients responded to further APC treatment. No major complications were recorded. CONCLUSION: APC is a safe and effective short-term treatment for GAVE. The natural history of the condition is uncertain, and at medium-term follow-up GAVE is found to recur in a substantial number of patients treated with APC. Re-treatment with APC is an option in these patients.

In vivo characterization of colonic thermal injury caused by argon plasma coagulation.

BACKGROUND: Argon plasma coagulation has been rapidly accepted for endoscopic obliteration of vascular lesions and superficial tumors. Depth of injury is thought to be limited through preferential discharge of energy to nondesiccated tissue. However, argon plasma coagulation-induced injury has not been well characterized. The aim of this study was to characterize argon plasma coagulation-induced colonic injury by using a porcine model. METHODS: Laparotomy was performed in 6 female swine and the colon exteriorized with the subjects under general anesthesia. Lesions were made with an argon plasma coagulation probe held perpendicular and 2 mm from the mucosa. Variables studied were as follows: power (45 W, 60 W, and 75 W) and duration (1, 2, or 3 seconds; n = 11 for each power/duration combination). Injury was graded as either superficial or deep, involving the muscularis propria. RESULTS: Circular muscle layer injury correlated closely with power (p = 0.02), duration (p = 0.001), and total energy delivered (r = 0.977). Longitudinal muscle damage was associated with duration of burn (p = 0.001) and total energy delivered (r = 0.855), but correlated poorly with power (p = 0.40). No perforations occurred. Submucosal injection of saline solution had a protective effect with reductions in circular (90% to 10%, p = 0.002) and longitudinal muscle injury (50% to 0%, p = 0.1). CONCLUSIONS: Injury to the muscularis propria occurs at recommended settings for argon plasma coagulation. Injury correlates with power setting, duration of burn, and total energy delivery. Protective arcing to nondesiccated tissue does not appear to be significant in vivo. Submucosal injection of saline solution protects against deep injury.

Liver metastasis following pneumoperitoneum with different gases in a mouse model.

BACKGROUND: The validity of using CO2 in laparoscopic tumor surgery has not yet been established. To address this question, we investigated the growth of liver metastases following insufflation with different gases in a mouse laparoscopy model. METHODS: Male BALB/C mice inoculated intraportally with colon 26 cells were randomized to undergo pneumoperitoneum with CO2 (n = 16), helium (n = 16), argon (n = 16), or air (n = 17), or to act as controls without insufflation (n = 17). RESULTS: The growth of cancer nodules on the liver 14 days after surgery was greater in mice following insufflation with CO2 (p < 0.01), helium (p < 0.01), argon (p = 0.01), and air (p = 0.07) than in control mice. No significant differences were found between the four insufflation groups in the growth of liver metastases. CONCLUSION: These results suggest that insufflation plays an important role in the development of liver metastases but that the choice of gas may not affect their growth.

Cardiac arrest associated with use of an argon beam coagulator during laparoscopic cholecystectomy.

We describe a cardiac arrest during use of an argon beam coagulation (ABC) system in an 82-yr-old woman having laparoscopic cholecystectomy under general and epidural anaesthesia. Intra-abdominal pressure (IAP) was controlled to less than 12 mm Hg during a carbon dioxide gas pneumoperitoneum and at first the operation was uneventful. When the ABC system (gas flow 6 litre min(-1)) was used to control local bleeding in the liver bed abdominal pressure increased rapidly to over 20 mm Hg and, 1 min later, the end-tidal carbon dioxide decreased to zero, followed by bradycardia and cardiac arrest. At once, an emergency laparotomy was performed and resuscitation begun. A mill-wheel murmur was heard on auscultation, leading to suspicion of argon gas embolism. Fortunately, recovery was completed with no neurological deficit. Anaesthesiologists should consider showed that argon gas embolism can occur with the ABC system during laparoscopic surgery.

Possible venous argon gas embolism complicating argon gas enhanced coagulation during liver surgery.

We report a case of a major venous argon embolism during argon beam coagulation of a liver biopsy. The essential signs were an abrupt reduction in end-tidal carbon dioxide partial pressure, in SpO2 and in systolic arterial pressure, at the time of coagulation. Spontaneous recovery was observed within 10 min. Precautions in respect of usage are highlighted.

[Tracheotomy: discussion of various surgical procedures using argon plasma coagulation]. / Tracheotomie: Diskussion zur Methodik und Mitteilung erster Erfahrungen mit der Argon-Plasma-Coagulation.

BACKGROUND: At present there is a discernible lack of consensus among different medical specialties regarding methods of tracheotomy in an intensive care setting. There is an obvious preference for percutaneous dilatational tracheotomy methods. Comparison of different methods are necessary to determine whether this trend is justified. METHOD: ENT and intensive care departments together performed 270 tracheotomies using different techniques in longtime-intubated adults over a period of 4 years. Severe complications were compared. Twenty conventional surgical tracheotomies were performed by using argon-plasma coagulation (APC). RESULTS: Comparison of 2175 percutaneous and 3263 conventional surgical tracheotomies reveals a nearly identical rate of severe perioperative complications. Percutaneous methods are most frequently used in patients with initially uncomplicated conditions. CONCLUSIONS: On the basis of our experience with 270 tracheotomies we have found there are clear indications for the various methods of tracheotomy. They depend on both the history of the disorder and its course and on the known contraindications to percutaneous tracheotomy methods. For safety reasons, we do not perform percutaneous tracheotomies on patients with severe brain damage who tend to aspirate and require prolonged neurological rehabilitation. Preoperative bleeding in percutaneous tracheostomies is the most important complication. It led to a life-threatening situation in 2.4% of our cases. Preoperative neck ultrasound may decrease the risks due to unusual anatomical conditions. Comparison of significant perioperative complications does not appear to favor any one method at present. In light of our effective cooperation with other specialties in planning and performing tracheotomies we do not feel that the current general preference for percutaneous methods in intensive care medicine is justified. Initial experience with APC shows promising results concerning its use in conventional tracheotomies. However, we noticed a shorter operation time, reduction of bleeding complications, and use of less suture material. The effectiveness of surgical intervention is improved by a number of factors.

Human teeth exposed to argon laser irradiation: determination of power-time-temperature working conditions.

OBJECTIVE: This study was conducted to establish the operating parameters of the argon laser without thermal damage to the pulp tissue for clinical applications. SUMMARY BACKGROUND DATA: Previous studies have mainly compared the temperature modifications of the pulp chamber in a very limited situation, where a complete view of the thermal history cannot be obtained nor even extrapolated to new applications. METHODS: We used samples of molar and premolar tooth where a class V cavity was prepared and illuminated with an argon laser at different power levels, fixing the exposition area for all cases. Situations including open cavity and teeth restoration were analyzed. High-precision thermistors were placed in four different positions, one of which was inside the pulp chamber. The temperature evolution was monitored continuously by an interfaced computer during all laser exposure. Special attention was paid to the intrapulpal temperature variation because it is considered the most vulnerable thermal region. The temperature time evolution allowed the determination of the operating conditions (power-time-temperature variation) in which the use of the argon laser causes no pulpal damage. As a function of temperature variation, we divided the whole parameter space (power-time-temperature) into zones and the optimum zone of operation was determined. CONCLUSIONS: We created a diagram called power-time-temperature (PTT) where zones of temperature increased under laser irradiation allow the verification of which condition is safe for clinical laser application. The results have a broad use when this type of analysis is applicable.