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Target Temperature (target + temperature)
Selected AbstractsUse of a Standardized Order Set for Achieving Target Temperature in the Implementation of Therapeutic Hypothermia after Cardiac Arrest: A Feasibility StudyACADEMIC EMERGENCY MEDICINE, Issue 6 2008J. Hope Kilgannon MD Abstract Objectives:, Induced hypothermia (HT) after cardiac arrest improved outcomes in randomized trials. Current post,cardiac arrest treatment guidelines advocate HT; however, utilization in practice remains low. One reported barrier to adoption is clinician concern over potential technical difficulty of HT. We hypothesized that using a standardized order set, clinicians could achieve HT target temperature in routine practice with equal or better efficiency than that observed in randomized trials. Methods:, After a multidisciplinary HT education program, we implemented a standardized order set for HT induction and maintenance including sedation and paralysis, intravenous cold saline infusion, and an external cooling apparatus, with a target temperature range of 33,34°C. We performed a retrospective analysis of a prospectively compiled and maintained registry of cardiac arrest patients with HT attempted (intent-to-treat) over the first year of implementation. The primary outcome measures were defined a priori by extrapolating treatment arm data from the largest and most efficacious randomized trial: 1) successful achievement of target temperature for ,85% of patients in the cohort and 2) median time from return of spontaneous circulation (ROSC) to achieving target temperature <8 hours. Results:, Clinicians attempted HT on 23 post,cardiac arrest patients (arrest location: 78% out-of-hospital, 22% in-hospital; initial rhythm: 26% ventricular fibrillation/tachycardia, 70% pulseless electrical activity or asystole) and achieved the target temperature in 22/23 (96%) cases. Median time from ROSC to target temperature was 4.4 (interquartile range 2.8,7.2) hours. Complication rates were low. Conclusions:, Using a standardized order set, clinicians can achieve HT target temperature in routine practice. [source] A simple and inexpensive capillary furnace for variable-temperature X-ray diffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2008Christine Lavigueur An inexpensive capillary furnace has been developed for variable-temperature X-ray diffraction in transmission geometry of air-stable liquid crystals and other materials. It offers temperature control with fluctuations of less than ±1,K in the range of interest for these samples, from room temperature to near 573,K. Phases can be accessed through heating or cooling with no significant overshooting of the target temperature. The furnace is designed to fit on a classical goniometer, and can be controlled by any standard temperature controller. The simple design of this furnace means that it is both inexpensive to build and easy to operate. [source] First Experiences for Pulmonary Vein Isolation with the High-Density Mesh Ablator (HDMA): A Novel Mesh Electrode Catheter for Both Mapping and Radiofrequency Delivery in a Single UnitJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009AXEL MEISSNER M.D. Background: Interventional therapy of atrial fibrillation (AF) is often associated with long examination and fluoroscopy times. The use of mapping catheters in addition to the ablation catheter requires multiple transseptal sheaths for left atrial access. Objectives: The purpose of this prospective study was to evaluate feasibility and safety of pulmonary vein (PV) isolation using the high-density mesh ablator (HDMA), a novel single, expandable electrode catheter for both mapping and radiofrequency (RF) delivery at the left atrium/PV junctions. Methods: Twenty-six patients with highly symptomatic paroxysmal AF (14, 53.8%) and persistent AF (12, 46.2%) were studied. Segmental PV isolation via the HDMA was performed using a customized pulsed RF energy delivery program (target temperature 55,60°C, power 70,100 W, 600,900 seconds RF application time/PV). Results: All 104 PVs in 26 patients could be ablated by the HDMA. Segmental PV isolation was achieved with a mean of 3.25 ± 1.4 RF applications for a mean of 603 ± 185 seconds. Entrance conduction block was obtained in 94.2% of all PV. The mean total procedure and fluoroscopy time was 159.0 ± 32 minutes and 33.5 ± 8.6 minutes, respectively. None of the patients experienced severe acute complications. After 3 months no PV stenosis was observed, and 85.6% and 41.6% of the patients with PAF and persistent AF, respectively, did not report symptomatic AF. Conclusions: In this first study of PV isolation using the HDMA, our findings suggest that this method is safe and yields good primary success rates. The HDMA simplifies AF ablation, favorably impacting procedure and fluoroscopy times. [source] Cooled Needle Catheter Ablation Creates Deeper and Wider Lesions Than Irrigated Tip Catheter AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2005ARAVINDA THIAGALINGAM F.R.A.C.P. Objectives: To design and test a catheter that could create deeper ablation lesions. Background: Endocardial radiofrequency (RF) ablation is unable to reliably create transmural ventricular lesions. We designed an intramural needle ablation catheter with an internally cooled 1.1-mm diameter straight needle that could be advanced up to 14 mm into the myocardium. The prototype catheter was compared with an irrigated tip ablation catheter. Methods: Ablation lesions were created under general anesthesia in 14 male sheep (weight 44 ± 7.3 kg) with fluoroscopic guidance. Each of the catheters was used to create two ablation lesions at randomly allocated positions within the left ventricle. The irrigation rate, target temperature, and maximum power were: 20 mL/min, 85°C, 50 W for the intramural needle catheter and 20 mL/min, 50°C, 50 W for the irrigated tip catheter, respectively. All ablations were performed for 2 minutes. After the last ablation, blue tetrazolium (12.5 mg/kg) was infused intravenously. The heart was removed via a left thoracotomy after monitoring the sheep for one hour. Results: There was no evidence of cardiac tamponade in any sheep. The intramural needle catheter lesions were significantly wider (10.9 ± 2.8 mm vs 10.1 ± 2.4 mm, P = 0.01), deeper (9.6 ± 2.0 mm vs 7.0 ± 1.3 mm, P = 0.01), and more likely to be transmural (38% vs 0%, P = 0.03). Conclusions: Cooled intramural needle ablation creates lesions that are significantly deeper and wider than endocardial RF ablation using an irrigated tip catheter in sheep hearts. This technology may be useful in treating ventricular tachycardia resistant to conventional ablation techniques. [source] Catheter Ablation of Chronic Atrial Fibrillation Targeting the Reinitiating TriggersJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2000MICHEL HAÏSSAGUERRE M.D. Trigger Ablation in Chronic AF. Introduction: We assessed the mode of reinitiation of atrial fibrillation (AF) after cardioversion and the efficacy of ablating these foci of reinitiation in patients with chronic AF. Methods and Results: Fifteen patients, 7 with structural heart disease, underwent mapping and catheter ablation of drug-resistant AF documented to he persistent for 5 ± 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowed mapping of the reinitiating trigger or the source of ectopy. Radiofrequency (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50°C and a power limit of 30 to 40 W, with the endpoint being interruption of all local muscle conduction. A total of 32 arrhythmogenic PVs and 2 atrial foci (left septum and left appendage) were identified: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by abolition of PV potentials in 8, but potentials persisted in 6. A single ablation session was performed in 7 patients and 8 underwent two or three sessions because of recurrence of AF; ablation was directed at the same source due to recovery of local PV potential or at a different PV. No PV stenosis was noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 ± 8 months. Anticoagulants were interrupted in 7 patients. Conclusion: PVs are the dominant triggers reinitiating chronic AF in this patient population. Elimination of PV potentials by ostial RF applications results in stable sinus rhythm in 60%. A larger group and longer follow-up are needed to investigate further the role of trigger ablation in curative therapy for chronic AF. [source] Prehospital therapeutic hypothermia for comatose survivors of cardiac arrest: a randomized controlled trialACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009A. KÄMÄRÄINEN Background: Intravenous infusion of ice-cold fluid is considered a feasible method to induce mild therapeutic hypothermia in cardiac arrest survivors. However, only one randomized controlled trial evaluating this treatment exists. Furthermore, the implementation rate of prehospital cooling is low. The aim of this study was to evaluate the efficacy and safety of this method in comparison with conventional therapy with spontaneous cooling often observed in prehospital patients. Methods: A randomized controlled trial was conducted in a physician-staffed helicopter emergency medical service. After successful initial resuscitation, patients were randomized to receive either +4 °C Ringer's solution with a target temperature of 33 °C or conventional fluid therapy. As an endpoint, nasopharyngeal temperature was recorded at the time of hospital admission. Results: Out of 44 screened patients, 19 were analysed in the treatment group and 18 in the control group. The two groups were comparable in terms of baseline characteristics. The core temperature was markedly lower in the hypothermia group at the time of hospital admission (34.1±0.9 °C vs. 35.2±0.8 °C, P<0.001) after a comparable duration of transportation. Otherwise, there were no significant differences between the groups regarding safety or secondary outcome measures such as neurological outcome and mortality. Conclusion: Spontaneous cooling alone is insufficient to induce therapeutic hypothermia before hospital admission. Infusion of ice-cold fluid after return of spontaneous circulation was found to be well tolerated and effective. This method of cooling should be considered as an important first link in the ,cold chain' of prehospital comatose cardiac arrest survivors. [source] Outcome, timing and adverse events in therapeutic hypothermia after out-of-hospital cardiac arrestACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009N. NIELSEN Background: Therapeutic hypothermia (TH) after cardiac arrest protects from neurological sequels and death and is recommended in guidelines. The Hypothermia Registry was founded to the monitor outcome, performance and complications of TH. Methods: Data on out-of-hospital cardiac arrest (OHCA) patients admitted to intensive care for TH were registered. Hospital survival and long-term outcome (6,12 months) were documented using the Cerebral Performance Category (CPC) scale, CPC 1,2 representing a good outcome and 3,5 a bad outcome. Results: From October 2004 to October 2008, 986 TH-treated OHCA patients of all causes were included in the registry. Long-term outcome was reported in 975 patients. The median time from arrest to initiation of TH was 90 min (interquartile range, 60,165 min) and time to achieving the target temperature (,34 °C) was 260 min (178,400 min). Half of the patients underwent coronary angiography and one-third underwent percutaneous coronary intervention (PCI). Higher age, longer time to return of spontaneous circulation, lower Glasgow Coma Scale at admission, unwitnessed arrest and initial rhythm asystole were all predictors of bad outcome, whereas time to initiation of TH and time to reach the goal temperature had no significant association. Bleeding requiring transfusion occurred in 4% of patients, with a significantly higher risk if angiography/PCI was performed (2.8% vs. 6.2%P=0.02). Conclusions: Half of the patients survived, with >90% having a good neurological function at long-term follow-up. Factors related to the timing of TH had no apparent association to outcome. The incidence of adverse events was acceptable but the risk of bleeding was increased if angiography/PCI was performed. [source] Scandinavian Clinical practice guidelines for therapeutic hypothermia and post-resuscitation care after cardiac arrestACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2009M. CASTRÉN Background and aim: Sudden cardiac arrest survivors suffer from ischaemic brain injury that may lead to poor neurological outcome and death. The reperfusion injury that occurs is associated with damaging biochemical reactions, which are suppressed by mild therapeutic hypothermia (MTH). In several studies MTH has been proven to be safe, with few complications and improved survival, and is recommended by the International Liaison of Committee on Resuscitation. The aim of this paper is to recommend clinical practice guidelines for MTH treatment after cardiac arrest from the Scandinavian Society of Anaesthesiology and Intensive Care Medicine (SSAI). Methods: Relevant studies were identified after two consensus meetings of the SSAI Task Force on Therapeutic Hypothermia (SSAITFTH) and via literature search of the Cochrane Central Register of Controlled Trials and Medline. Evidence was assessed and consensus opinion was used when high-grade evidence (Grade of Recommendation, GOR) was unavailable. A management strategy was developed as a consensus from the evidence and the protocols in the participating countries. Results and conclusion: Although proven beneficial only for patients with initial ventricular fibrillation (GOR A), the SSAITFTH also recommend MTH after restored spontaneous circulation, if active treatment is chosen, in patients with initial pulseless electrical activity and asystole (GOR D). Normal ethical considerations, premorbid status, total anoxia time and general condition should decide whether active treatment is required or not. MTH should be part of a standardized treatment protocol, and initiated as early as possible after indication and treatment have been decided (GOR E). There is insufficient evidence to make definitive recommendations among techniques to induce MTH, and we do not know the optimal target temperature, duration of cooling and rewarming time. New studies are needed to address the question as to how MTH affects, for example, prognostic factors. [source] Linear Ablation with Duty-Cycled Radiofrequency Energy at the Cavotricuspid IsthmusPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2010STEFANIE BOLL Background: Multielectrode catheters using duty-cycled radiofrequency (RF) have been developed to treat atrial fibrillation (AF). Many of these patients also have atrial flutter. Therefore, a linear multielectrode has been developed using the same RF energy. Objective: The concept and acute results of linear ablation using duty-cycled RF were tested in the cavotricuspid isthmus (CTI). Methods: The CTI was targeted in 75 patients, in 68 (90%) among them as an adjunct to AF ablation with the same technology. A linear electrode catheter with a 4-mm tip and five 2-mm ring electrodes was connected to a generator titrating duty-cycled RF at 20,45 W up to a target temperature of 70°C in 1:1 unipolar/bipolar mode. Results: During a mean procedure time of 20 ± 12 minutes, complete CTI block was achieved by 4 ± 3 applications of duty-cycled RF in 69 (92%) patients. No more than three RF applications were necessary in 60% of patients. During the initial learning curve, standard RF had to be used in five (7%) patients. Complete block was not achieved in one patient with frequent episodes of AF. Char was observed in five (7%) patients with poor electrode cooling; consequently, the temperature ramp-up was slowed and manually turned off in the event of low-power delivery. Two groin hematomas occurred; otherwise, no clinical complications were observed. Conclusion: Multielectrode catheters delivering duty-cycled RF can effectively ablate the CTI with few RF applications with promising acute results. Further modifications are necessary to improve catheter steering and prevent char formation. (PACE 2010; 444,450) [source] C. botulinum inactivation kinetics implemented in a computational model of a high-pressure sterilization processBIOTECHNOLOGY PROGRESS, Issue 1 2009Pablo Juliano Abstract High-pressure, high-temperature (HPHT) processing is effective for microbial spore inactivation using mild preheating, followed by rapid volumetric compression heating and cooling on pressure release, enabling much shorter processing times than conventional thermal processing for many food products. A computational thermal fluid dynamic (CTFD) model has been developed to model all processing steps, including the vertical pressure vessel, an internal polymeric carrier, and food packages in an axis-symmetric geometry. Heat transfer and fluid dynamic equations were coupled to four selected kinetic models for the inactivation of C. botulinum; the traditional first-order kinetic model, the Weibull model, an nth-order model, and a combined discrete log-linear nth-order model. The models were solved to compare the resulting microbial inactivation distributions. The initial temperature of the system was set to 90°C and pressure was selected at 600 MPa, holding for 220 s, with a target temperature of 121°C. A representation of the extent of microbial inactivation throughout all processing steps was obtained for each microbial model. Comparison of the models showed that the conventional thermal processing kinetics (not accounting for pressure) required shorter holding times to achieve a 12D reduction of C. botulinum spores than the other models. The temperature distribution inside the vessel resulted in a more uniform inactivation distribution when using a Weibull or an nth-order kinetics model than when using log-linear kinetics. The CTFD platform could illustrate the inactivation extent and uniformity provided by the microbial models. The platform is expected to be useful to evaluate models fitted into new C. botulinum inactivation data at varying conditions of pressure and temperature, as an aid for regulatory filing of the technology as well as in process and equipment design. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Use of a Standardized Order Set for Achieving Target Temperature in the Implementation of Therapeutic Hypothermia after Cardiac Arrest: A Feasibility StudyACADEMIC EMERGENCY MEDICINE, Issue 6 2008J. Hope Kilgannon MD Abstract Objectives:, Induced hypothermia (HT) after cardiac arrest improved outcomes in randomized trials. Current post,cardiac arrest treatment guidelines advocate HT; however, utilization in practice remains low. One reported barrier to adoption is clinician concern over potential technical difficulty of HT. We hypothesized that using a standardized order set, clinicians could achieve HT target temperature in routine practice with equal or better efficiency than that observed in randomized trials. Methods:, After a multidisciplinary HT education program, we implemented a standardized order set for HT induction and maintenance including sedation and paralysis, intravenous cold saline infusion, and an external cooling apparatus, with a target temperature range of 33,34°C. We performed a retrospective analysis of a prospectively compiled and maintained registry of cardiac arrest patients with HT attempted (intent-to-treat) over the first year of implementation. The primary outcome measures were defined a priori by extrapolating treatment arm data from the largest and most efficacious randomized trial: 1) successful achievement of target temperature for ,85% of patients in the cohort and 2) median time from return of spontaneous circulation (ROSC) to achieving target temperature <8 hours. Results:, Clinicians attempted HT on 23 post,cardiac arrest patients (arrest location: 78% out-of-hospital, 22% in-hospital; initial rhythm: 26% ventricular fibrillation/tachycardia, 70% pulseless electrical activity or asystole) and achieved the target temperature in 22/23 (96%) cases. Median time from ROSC to target temperature was 4.4 (interquartile range 2.8,7.2) hours. Complication rates were low. Conclusions:, Using a standardized order set, clinicians can achieve HT target temperature in routine practice. [source] | ||||||||||