Geometrical Changes of the Aorta as Predictors for Thromboembolic Events After EVAR With the Anaconda Stent-Graft.

PURPOSE: Thromboembolic events (TE), including limb graft occlusion (LGO) and distal limb embolization (DLE), are common complications after endovascular aneurysm repair (EVAR). The aim of this study was to find predictors for TE in patients treated with the Anaconda stent-graft for infrarenal aneurysms. MATERIALS AND METHODS: Geometrical and anatomical variables were retrospectively analyzed in a consecutive Anaconda cohort. Pre- and postoperative CT scans were used to derive geometrical parameters length, curvature, torsion, and tortuosity index (TI) from the center lumen lines (CLLs). Limb characteristics, pre-to-post EVAR and mid-term-follow-up changes in the parameters were evaluated for their predictive value for TE. RESULTS: Eighty-four patients (mean age 74±8.3 years, 74 men) were enrolled. The risk of TE was lowered with pre-to-post implant decreasing TI (steps of 0.05: OR: 1.30, 95% CI: 1.01-1.66, p=0.04), pre-to-post implant decreasing mean curvature (OR: 1.08, 95% CI: 1.01-1.16, p=0.03), and a larger degree of circumferential common iliac artery (CIA) calcification (OR: 0.98, 95% CI: 0.97-1.00, p=0.03). The only LGO predictor was the caudal relocation of maximal curvature after EVAR (OR: 1.01, 95% CI: 1.00-1.01, p=0.04). Preventors of DLE were CIA diameter (OR: 0.87, 95% CI: 0.76-0.99, p=0.04), circumferential CIA calcification (OR: 0.97, 95% CI: 0.95-1.00, p=0.03), mean and maximal curvature of the preoperative aortoiliac trajectory (OR: 0.86, 95% CI: 0.79-0.94, p<0.01 and OR: 0.97, 95% CI: 0.95-1.00, p=0.03, respectively) and pre-to-postoperative decrease in mean curvature (OR: 1.11, 95% CI: 1.02-1.21, p=0.02). Midterm TE predictors were length (OR: 0.95, 95% CI: 0.89-1.01, p=0.08) and torsion maximum location (OR: 1.01, 95% CI: 0.99-1.01, p=0.10). CONCLUSION: The present study confirms that treatment of infrarenal AAA with an Anaconda stent-graft is related to a relatively high TE rate which decreases with a pre-to-postoperative reduction in curvature and TI, and a larger degree of circumferential CIA calcification. In other words, more aortoiliac straightening and more circumferential CIA calcification may prevent TE development after EVAR with this stent-graft.

Increasing the reflection efficiency of the Sedaconda ACD-S by heating and cooling the anaesthetic reflector: a bench study using a test lung.

BACKGROUND: As volatile anaesthetic gases contribute to global warming, improving the efficiency of their delivery can reduce their environmental impact. This can be achieved by rebreathing from a circle system, but also by anaesthetic reflection with an open intensive care ventilator. We investigated whether the efficiency of such a reflection system could be increased by warming the reflector during inspiration and cooling it during expiration (thermocycling). METHODS: The Sedaconda-ACD-S (Sedana Medical, Danderyd, Sweden) was connected between an intensive care ventilator and a test lung. Liquid isoflurane was infused into the device at 0.5, 1.0, 2.0 and 5.0 mL/h; ventilator settings were 500 mL tidal volume, 12 bpm, 21% oxygen. Isoflurane concentrations were measured inside the test lung after equilibration. Thermocycling was achieved by heating the breathing gas in the inspiratory hose to 37 °C via a heated humidifier without water. Breathing gas expired from the test lung was cooled to 14 °C before reaching the ACD-S. In the test lung, body temperature pressure saturated conditions prevailed. Isoflurane concentrations and reflective efficiency were compared between thermocycling and control conditions. RESULTS: With thermocycling higher isoflurane concentrations in the test lung were measured for all infusion rates studied. Interpolation of data showed that for achieving 0.4 (0.6) Vol% isoflurane, the infusion rate can be reduced from 1.2 to 0.7 (2.0 to 1.2) mL/h or else to 56% (58%) of control. CONCLUSION: Thermocycling of the anaesthetic gas considerably increases the efficiency of the anaesthetic reflector and reduces anaesthetic consumption by almost half in a test lung model. Given that cooling can be miniaturized, this method carries a potential for further saving anaesthetics in clinical practice in the operating theatre as well as for inhaled sedation in the ICU.

In vitro performance evaluation of AnaConDaTM-100 and AnaConDaTM-50 compared to a circle breathing system for control and consumption of volatile anaesthetics.

To identify the better volatile anaesthetic delivery system in an intensive care setting, we compared the circle breathing system and two models of reflection systems (AnaConDa™ with a dead space of 100 ml (ACD-100) or 50 ml (ACD-50)). These systems were analysed for the parameters like wash-in, consumption, and wash-out of isoflurane and sevoflurane utilising a test lung model. The test lung was connected to a respirator (circle breathing system: Aisys CS™; ACD-100/50: Puriton Bennett 840). Set parameters were volume-controlled mode, tidal volume-500 ml, respiratory rate-10/min, inspiration time-2 sec, PEEP-5 mbar, and oxygen-21%. Wash-in, consumption, and wash-out were investigated at fresh gas flows of 0.5, 1.0, 2.5, and 5.0 l/min. Anaesthetic target concentrations were 0.5, 1.0, 1.5, 2.0, and 2.5%.  Wash-in was slower in ACD-100/-50 compared to the circle breathing system, except for fresh gas flows of 0.5 and 1.0 l/min. The consumption of isoflurane and sevoflurane in ACD-100 and ACD-50 corresponded to the fresh gas flow of 0.5-1.0 l/min in the circle breathing system. Consumption with ACD-50 was higher in comparison to ACD-100, especially at gas concentrations > 1.5%. Wash-out was quicker in ACD-100/-50 than in the circle breathing system at a fresh gas flow of 0.5 l/min, however, it was longer at all the other flow rates. Wash-out was comparable in ACD-100 and ACD-50. Wash-in and wash-out were generally quicker with the circle breathing system than in ACD-100/-50. However, consumption at 0.5 minimum alveolar concentration was comparable at flows of 0.5 and 1.0 l/min.

Inhaled Anesthetics for Sedation in ICU: Widening Horizons!

How to cite this article: Krishna B. Inhaled Anesthetics for Sedation in ICU: Widening Horizons! Indian J Crit Care Med 2022;26(8):889-891.

Nineteen-year outcomes with the Anaconda stent graft system from two tertiary centers.

OBJECTIVE: The Anaconda stent graft device presents peculiar and unique features in its design and deployment sequence, available on the market for many years with minor modifications, among different generations. The aim of this study was to assess the long-term, real-life, outcomes obtained in two high-volume centers with this endograft for infrarenal aortic aneurysms treatment over a period of 19 years. METHODS: All patients treated with the investigated device between 2000 and 2019, with at least 1 year of follow-up, were entered into a prospective database and data were reviewed retrospectively. The long-term results were assessed according to the Kaplan-Meier method. Primary outcomes were overall survival, freedom from AAA rupture, and freedom from AAA-related death. Secondary outcomes were freedom from late reintervention, freedom from late conversion to open repair, freedom from late limb occlusion, and freedom from late EVAR failure. RESULTS: A total of 260 consecutive patients were treated during the study period. Technical success was achieved in 98.5% (256/260) of the cases. Two perioperative deaths (0.8%) and four major complications (1.5%) were recorded. At a mean follow-up of 54 ± 38 months (summary follow-up index = 0.86), the late survival estimate was 94.8% at 1 year, 75.2% at 5 years, 50.5% at 10 years, and 43.3% at 13 years, with no case of late AAA rupture or late AAA-related death. Late freedom from conversion was 99.2% at 1 year, 96.9% at 5 years, 94.0% at 10 years, and 94.0% at 13 years. Freedom from late limb thrombosis was 96.8% at 1 year and 91.0% at 5, 10, and 13 years. Estimates of freedom from late reintervention was 95.6% at 1 year, 87.0% at 5 years, 77.4% at 10 years, and 77.4% at 13 years. Estimates of limb thrombosis at 11 years were significantly different in patients receiving or not intraoperative iliac kissing balloon maneuver with noncompliant angioplasty catheters (98.0% vs 88.4%; P = .029). CONCLUSIONS: The Anaconda stent graft demonstrated effective and durable outcomes for AAA treatment over a 19-year period, with no case of late AAA rupture or AAA related death in the studied population. Late limb occlusion was the leading cause of reintervention; however, a positive prevention strategy was found in intraoperative kissing balloon, which was associated with significant reduced rate of iliac thrombosis over time.

Long-Term Inhalative Sedation in Children With Pulmonary Diseases.

OBJECTIVES: To describe safety and feasibility of long-term inhalative sedation (LTIS) in children with severe respiratory diseases compared to patients with normal lung function with respect to recent studies that showed beneficial effects in adult patients with acute respiratory distress syndrome (ARDS). DESIGN: Single-center retrospective study. SETTING: 12-bed pediatric intensive care unit (PICU) in a tertiary-care academic medical center in Germany. PATIENTS: All patients treated in our PICU with LTIS using the AnaConDa® device between July 2011 and July 2019. MEASUREMENTS AND MAIN RESULTS: Thirty-seven courses of LTIS in 29 patients were analyzed. LTIS was feasible in both groups, but concomitant intravenous sedatives could be reduced more rapidly in children with lung diseases. Cardiocirculatory depression requiring vasopressors was observed in all patients. However, severe side effects only rarely occured. CONCLUSIONS: In this largest cohort of children treated with LTIS reported so far, LTIS was feasible even in children with severely impaired lung function. From our data, a prospective trial on the use of LTIS in children with ARDS seems justified. However, a thorough monitoring of cardiocirculatory side effects is mandatory.

Inhaled sedation with sevoflurane in critically ill children during extracorporeal membrane oxygenation.

Sedation can be challenging in critically ill children. Inhaled anesthetics such as sevoflurane have proved to be useful in difficult or long-term sedation. However, its use in children out of the operating room is still limited and little is yet known about its use in patients undergoing ECMO with no previous reports in children. The objective is to assess the effectiveness and safety of sevoflurane during ECMO in two pediatric patients. Sedation was successfully achieved in both patients, and patients' contribution to breathing was possible even with deep sedation. There were not any side effects during sevoflurane treatment or after withdrawal.

Comparison of isoflurane and propofol sedation in critically ill COVID-19 patients-a retrospective chart review.

PURPOSE: In this retrospective study, we compared inhaled sedation with isoflurane to intravenous propofol in invasively ventilated COVID-19 patients with ARDS (Acute Respiratory Distress Syndrome). METHODS: Charts of all 20 patients with COVID-19 ARDS admitted to the ICU of a German University Hospital during the first wave of the pandemic between 22/03/2020 and 21/04/2020 were reviewed. Among screened 333 days, isoflurane was used in 97 days, while in 187 days, propofol was used for 12 h or more. The effect and dose of these two sedatives were compared. Mixed sedation days were excluded. RESULTS: Patients' age (median [interquartile range]) was 64 (60-68) years. They were invasively ventilated for 36 [21-50] days. End-tidal isoflurane concentrations were high (0.96 ± 0.41 Vol %); multiple linear regression yielded the ratio (isoflurane infusion rate)/(minute ventilation) as the single best predictor. Infusion rates were decreased under ECMO (3.5 ± 1.4 versus 7.1 ± 3.2 ml∙h-1; p < 0.001). In five patients, the maximum recommended dose of propofol of 4 mg∙hour-1∙kg-1ABW was exceeded on several days. On isoflurane compared to propofol days, neuro-muscular blocking agents (NMBAs) were used less frequently (11% versus 21%; p < 0.05), as were co-sedatives (7% versus 31%, p < 0.001); daily opioid doses were lower (720 [720-960] versus 1080 [720-1620] mg morphine equivalents, p < 0.001); and RASS scores indicated deeper levels of sedation (- 4.0 [- 4.0 to - 3.0] versus - 3.0 [- 3.6 to - 2.5]; p < 0.01). CONCLUSION: Isoflurane provided sufficient sedation with less NMBAs, less polypharmacy and lower opioid doses compared to propofol. High doses of both drugs were needed in severely ill COVID-19 patients.

ANACONDA: a new tool to improve mortality and cause of death data.

BACKGROUND: The need to monitor the Sustainable Development Goals (SDGs) and to have access to reliable and timely mortality data has created a strong demand in countries for tools that can assist them in this. ANACONDA (Analysis of National Causes of Death for Action) is a new tool developed for this purpose which allows countries to assess how accurate their mortality and cause of death are. Applying ANACONDA will increase confidence and capacity among data custodians in countries about their mortality data and will give them insight into quality problems that will assist the improvement process. METHODS: ANACONDA builds on established epidemiological and demographic concepts to operationalise a series of 10 steps and numerous sub-steps to perform data checks. Extensive use is made of comparators to assess the plausibility of national mortality and cause of death statistics. The tool calculates a composite Vital Statistics Performance Index for Quality (VSPI(Q)) to measure how fit for purpose the data are. Extracts from analyses of country data are presented to show the types of outputs. RESULTS: Each of the 10 steps provides insight into how well the current data is describing different aspects of the mortality situation in the country, e.g. who dies of what, the completeness of the reporting, and the amount and types of unusable cause of death codes. It further identifies the exact codes that should not be used by the certifying physicians and their frequency, which makes it possible to institute a focused correction procedure. Finally, the VSPI(Q) allows periodic monitoring of data quality improvements and identifies priorities for action to strengthen the Civil Registration and Vital Statistics (CRVS) system. CONCLUSIONS: ANACONDA has demonstrated the potential to dramatically improve knowledge about disease patterns as well as the functioning of CRVS systems and has served as a platform for galvanising wider CRVS reforms in countries.

Outcomes after treatment of complex aortic abdominal aneurysms with the fenestrated Anaconda endograft.

OBJECTIVE: To date, information on the fenestrated Anaconda endograft is limited to case series with a small sample size. This study was performed to assess the technical and clinical outcome of this device in a large international case series. METHODS: All worldwide centers having treated more than 15 complex abdominal aortic aneurysms (AAA) or type IV thoracoabdominal aortic aneurysm patients with the fenestrated Anaconda endograft were approached. Main outcome parameters were procedural technical success, postoperative and follow-up clinical outcome for endoleaks, target vessel patency, reintervention rate, and patient survival. RESULTS: Three hundred thirty-five consecutive cases treated between June 2010 and May 2018 in 11 sites were included. Patients were treated for a short neck infrarenal (n = 98), juxtarenal (n = 191), suprarenal AAA (n = 27), or type IV thoracoabdominal aortic aneurysm (n = 19). Mean age was 73.6 ± 4.6 years (292 male). Endografts contained a total of 920 fenestrations, with a mean of 2.7 ± 0.8 fenestrations per case. Technical success was 88.4% (primary, 82.7%; assisted primary 5.7%). In 6.9% of cases, a procedural type IA endoleak was observed, spontaneously disappearing in 82.6% during early follow-up. The development of a type IA endoleak was associated with greater neck angulation (odds ratio [OR], 0.94; P = .01), three fenestrations (OR, 42.7; P = .01) and the presence of augmented proximal rings (OR, 0.17; P = .03). Median follow-up was 1.2 years (interquartile range, 0.4-2.6). The mean estimated glomerular filtration rate deteriorated from 67.6 ± 19.3 mL/min/1.73 m2 preoperatively to 59.3 ± 22.7 mL/min/1.73 m2 at latest follow-up (P = .00). The freedom from AAA growth were 97.9 ± 0.9% (n = 190) and 86.4 ± 3.0% (n = 68), with a freedom from AAA rupture of 99.7 ± 0.3% (n = 191) and 99.1 ± 0.7% (n = 68), at 1 and 3 years, respectively. The endoleak-free survival, excluding spontaneously resolved procedural endoleaks, at 1 and 3 years was 73.4 ± 2.6 (n = 143) and 65.6 ± 3.4% (n = 45), respectively. The target vessel patency at one and three years were 96.4 ± 0.7% (n = 493) and 92.7 ± 1.4% (n = 156), respectively. A total of 75 reinterventions were done in 64 cases (19.1%), of which 25 cases for an endoleak. The reintervention-free survival at 1 and 3 years were 83.6 ± 2.2% (n = 190) and 71.0 ± 3.7% (n = 68), respectively. No deaths during procedure, extending within 24 hours postoperatively, were observed. Within 30 days 14 patients (4.2%) died and during follow-up another 39 patients (11.6%) died. Three deaths were considered AAA related (one rupture, one endograft infection, and one bilateral renal artery occlusion). The estimated cumulative survival at 1 and 3 years were 89.8 ± 1.8% (n = 191) and 79.2 ± 3.0% (n = 68), respectively. CONCLUSIONS: The custom-made fenestrated Anaconda endograft is a valuable option for the treatment of a complex AAA. A procedural type IA endoleak is seen relatively frequently, but spontaneously resolves in most cases.

The Italian Multicentre Registry of Fenestrated Anaconda™ Endografts for Complex Abdominal Aortic Aneurysms Repair.

OBJECTIVE: The aim was to describe the outcomes of the Anaconda™ Fenestrated endograft Italian Registry for complex aortic aneurysms (AAAs), unsuitable for standard endovascular aneurysm repair (EVAR). METHODS: Between 2012 and 2018 patients with a proximal neck unsuitable for standard EVAR, treated with the fenestrated Anaconda™ endograft, were prospectively enrolled in a dedicated database. Endpoints were peri-operative technical success (TS) and evaluation of type Ia/b or 3 endoleaks (T1/3 EL), target visceral vessel (TVV) occlusion, re-interventions, and AAA related mortality at 30 days, six months, and later follow up. RESULTS: One hundred twenty seven patients (74 ± 7 years, American Society Anesthesiology (ASA) II/III/IV: 12/85/30) were included in the study in 49 Italian Vascular Surgery Units (83 juxta/para-renal AAA, 13 type IV thoraco-abdominal AAA, 16 T1aEL post EVAR, and 15 short neck AAA). Configurations with one, two, three, and four fenestrations were used in 5, 56, 39, and 27 cases, respectively, for a total of 342 visceral vessels. One hundred and eight (85%) bifurcated and 19 (15%) tube endografts were implanted. In 35% (44/127) of cases the endograft was repositioned during the procedure, and 37% (128/342) of TVV were cannulated from brachial access. TS was 87% (111/127): five T1EL, six T3EL (between fenestration and vessel stent), and six loss of visceral vessels (one patient with a Type Ia EL had also a TVV loss) occurred. Thirty day mortality was 4% (5/127). Two of the five T1EL resolved spontaneously at 30 days. The overall median follow up was 21 ± 16 months; one T1EL (5%) occurred at six months and one T3EL (4%) at the three year follow up. Another two (3%) TVV occlusions occurred at six months and five (3%) at three years. The re-intervention rate at the 30 days, six months, and three year follow up was 5%, 7%, and 18 ± 5%, respectively. CONCLUSION: The fenestrated Anaconda™ endograft is effective in the treatment of complex AAA. Some structure properties, such as the re-positionability and the possibility of cannulation from above, are specific characteristics helpful for the treatment of some complex anatomies.

Five Year Results of the French EPI-ANA-01 Registry of AnacondaTM Endografts in the Treatment of Infrarenal Abdominal Aortic Aneurysms.

OBJECTIVE: A significant decrease in aneurysm related survival is observed at long term follow up after infrarenal endovascular aneurysm repair (EVAR) compared with open repair. Therefore, longer term results with new generation endografts are essential. The aim of this post-approval French multicentre prospective observational study (EPI-ANA-01) was to evaluate the technical success and five year mortality and secondary intervention rates of the third generation AnacondaTM endograft. METHODS: From June 2012 to October 2013, 176 consecutive unruptured infrarenal abdominal aortic aneurysms were included (160 male patients, mean age 75.3 ± 8.4 years). Survival, freedom from type Ia endoleak, limb events, and re-interventions were estimated using the Kaplan-Meier method. Anatomical and clinical characteristics were compared according to the occurrence of migration, conversion, adverse limb events, endoleak, and sac enlargement. RESULTS: The primary technical and clinical success rates were 98.3% and 94.9%, respectively. A hostile neck was identified in 33.9% of patients and 10.7% were treated outside instructions for use (IFU). An early post-operative (≤30 days) mortality rate of 1.7% was observed. At one and five years, respectively, the overall survival rate was 94.9% and 65.9% (aneurysm related in four patients [2.3%]) and the clinical success rate was 90.9% and 70.6%. Secondary interventions were performed in 35 of 176 patients (19.9%). The overall limb occlusion rate was 7.9% and the aneurysm sac diameter decreased significantly (pre-operative diameter 53.9 ± 8.6 mm vs. 42.3 ± 14.7 mm at five years; p < .001). Patients treated outside the instructions for use (IFU) had significantly higher rates of migration, surgical conversion, and aneurysm sac expansion (p = .03). CONCLUSION: The Anaconda endograft provides high technical success and satisfactory five year aneurysm exclusion and clinical success rates. However, implantation outside the IFU should be avoided, as it leads to significantly worse outcomes, and caution over the risk of limb occlusion and distal embolisation should be observed.

Assessment of the quality of cause-of-death data in Greenland, 2006-2015.

Background: While the system of registration of mortality and cause of death (COD) in Greenland was established several decades ago, reporting procedures follow a complicated administrative process. Timely and reliable reporting on mortality and COD is of high importance for the usability of the collected data for research, health planning and decision making. Methods: COD data collected by the Chief Medical Office in Greenland from 2006 to 2015 (4490 registered deaths) were analysed with the software Analysis of National Causes of Death for Action (ANACONDA) v4.0. Unusable or insufficiently specified ICD codes are identified. The Vital Statistics Performance Index for Quality (VSPI(Q)) is estimated for the overall quality conclusions of the register's usability. Results: Sixty-eight per cent of the input data for Greenland was coded with a usable underlying COD, 24% with an unusable cause and 8% of deaths with an insufficiently specified cause. Almost 700 deaths were coded to an unusable code of 'very high impact'. The most prevalent unusable underlying causes were other ill-defined and unspecified causes, including no death certificate available, followed by senility, heart failure, sepsis and shock and cardiac arrest. The VSPI(Q) score was 66%, representing medium quality. Conclusions: In the 10 years' worth of data analysed, the true underlying COD in many cases was unknown. Several likely explanations for this include lack of systematic COD training for physicians, logistic and capacity challenges in Greenland that potentially could reduce the quality of the collected data and its usability in providing essential information about the true pattern of mortality in Greenland.

Early results with the custom-made Fenestrated Anaconda aortic cuff in the treatment of complex abdominal aortic aneurysm.

OBJECTIVE: The objective of this study was to investigate the feasibility of a specific custom-made fenestrated aortic cuff in the treatment of complex abdominal aortic aneurysms (AAAs). METHODS: Between 2013 and 2016, a total of 57 custom-made Fenestrated Anaconda (Vascutek, Inchinnan, Scotland, UK) aortic cuffs were placed in 38 centers worldwide. All centers were invited to participate in this retrospective analysis. Postoperative and follow-up data included the presence of adverse events, necessity for reintervention, and renal function. RESULTS: Fifteen clinics participated, leading to 29 cases. Median age at operation was 74 years (interquartile range [IQR], 71-78 years); five patients were female. Two patients were treated for a para-anastomotic AAA after open AAA repair, 19 patients were treated because of a complicated course after primary endovascular AAA repair, and 8 cases were primary procedures for AAA. A total of 76 fenestrations (mean, 2.6 per case) were used. Four patients needed seven adjunctive procedures. Two patients underwent conversion, one because of a dissection of the superior mesenteric artery and one because of perforation of a renal artery. Median operation time was 225 minutes (IQR, 150-260 minutes); median blood loss, 200 mL (IQR, 100-500 mL); and median contrast volume, 150 mL (IQR, 92-260 mL). Primary technical success was achieved in 86% and secondary technical success in 93%. The 30-day morbidity was 7 of 29 with a mortality rate of 4 of 29. Estimated glomerular filtration rate remained unchanged before and after surgery (76 to 77 mL/min/m2). Between preoperative and median follow-up of 11 months, estimated glomerular filtration rate was reduced statistically significantly (76 to 63 mL/min/m2). During follow-up, 9 cases had an increase in aneurysm sac diameter (5 cases >5 mm); 14 cases had a stable or decreased aneurysm sac diameter; and in 2 cases, no aneurysm size was reported. No type I endoleak was reported, and two cases with a type III endoleak were treated by endovascular means during follow-up. Survival, reintervention-free survival, and target vessel patency at 1 year were 81% ± 8%, 75% ± 9%, and 99% ± 1%, respectively. After 2 years, these numbers were 81% ± 8%, 67% ± 11%, and 88% ± 6%, respectively. During follow-up, the two patients with a type III endoleak needed endograft-related reinterventions. CONCLUSIONS: Treatment with this specific custom-made fenestrated aortic cuff is feasible after complicated previous (endovascular) aortic repair or in complex AAAs. The complexity of certain AAA cases is underlined in this study, and the Fenestrated Anaconda aortic cuff is a valid option in selected cases in which few treatment options are left.

Abdominal aortic aneurysm neck remodeling after Anaconda stent graft implantation.

OBJECTIVE: The aim of this study was to define how the proximal landing zone changes geometrically after endovascular abdominal aortic aneurysm repair (EVAR) with the Anaconda (Vascutek, Inchinnan, United Kingdom) stent graft. METHODS: Among 230 patients who underwent Anaconda stent graft implantation between 2005 and 2014, we included 126 with adequate computed tomography (CT) image quality and follow-up. CT analysis entailed the geometric changes in the main body, proximal rings, and proximal landing zone. The median CT follow-up was 2.0 years (345.8 patients-years). RESULTS: The proximal portion of the main body ring system flattened within the first year after EVAR, resulting in an up to 30° increase in the upper ring's angle in 40% patients and up to 40° increase in 24% patients. One year after EVAR, the upper ring angle increase slowed down. Aortic diameter measured at the level of the upper and lower ring expanded by 2 to 4 mm within 1 year, but remained unchanged afterward. The main body migrated continuously down toward the aortic bifurcation, attaining an average 6-mm increase in the distance between the superior mesenteric artery and main body within 4 years. Freedom from endoleak type IA was 95 ± 2% and 93 ± 3% after 1 and 4 years, respectively. CONCLUSIONS: The Anaconda main body ring system in its proximal portion flattens within the first year after EVAR, leading to an increase of 2 to 4 mm in the proximal landing zone's aortic diameter. The main body migrates slowly but continuously down toward the aortic bifurcation.

Inhalative sedation with small tidal volumes under venovenous ECMO.

BACKGROUND: Inhalative sedation is an emerging method for long-term sedation in intensive care therapy. There is evidence that it is easy to control and may be beneficial compared to intravenous sedation. Yet little is known about the use in patients with compromised lung function. In this retrospective analysis, we searched files of patients receiving inhalative sedation under venovenous extracorporeal membrane oxygenator (vv-ECMO) support due to lung failure. METHODS: After ethical approval, we performed a retrospective analysis of patients receiving vv-ECMO support and inhalative sedation in the surgical ICU in 2015. Isoflurane was administered via the AnaConDa®-system. Sedation was tested using Richmond Agitation and Sedation scale (RASS). RESULTS: 7 patients were identified. Median age was 50 years (26/70 years). All were male. Median ECMO runtime was 129 h (37/1008 h) and the survival rate was 57.9%. Dose of isoflurane was 1.7 ml/h (0.8 / 4.0 ml/h) resulting in expiratory concentrations of 0.8 Vol% (0.3/1.8 Vol%), inspiratory of 0.6 Vol% (0.1/1.4 Vol%). Higher concentrations of isoflurane were associated with increased depth of sedation (expiratory p = 0.016; inspiratory p = 0.027; averaged p = 0.015). With tidal volume below 350 ml, association was still present for expiratory and averaged concentrations of isoflurane (expiratory p = 0.031; inspiratory p = 0.082; average p = 0.039). CONCLUSIONS: This is the first study that shows that inhalative concentrations of isoflurane are associated with depth of sedation in patients with lung failure. We were able to show that even with major impacts in lung mechanics and function targeted sedation with volatile anaesthetics is feasible and dose-response relationship appears to exist.

Efficient application of volatile anaesthetics: total rebreathing or specific reflection?

The circle system has been in use for more than a 100 years, whereas the first clinical application of an anaesthetic reflector was reported just 15 years ago. Its functional basis relies on molecular sieves such as zeolite crystals or activated carbon. In a circle system, the breathing gas is rebreathed after carbon dioxide absorption; a reflector on the other hand specifically retains the anaesthetic during expiration and resupplies it during the next inspiration. Reflection systems can be used in conjunction with intensive care ventilators and do not need the permanent presence of trained qualified staff. Because of easy handling and better ventilatory capabilities of intensive care ventilators, reflection systems facilitate the routine use of volatile anaesthetics in intensive care units. Until now, there are three reflection systems commercially available: the established AnaConDa™ (Sedana Medical, Uppsala, Sweden), the new smaller AnaConDa-S™, and the Mirus™ (Pall Medical, Dreieich, Germany). The AnaConDa consists only of a reflector which is connected to a syringe pump for infusion of liquid sevoflurane or isoflurane. The Mirus represents a technical advancement; its control unit includes a gas and ventilation monitor as well as a gas dispensing unit. The functionality, specific features, advantages and disadvantages of both systems are discussed in the text.

Evaluating the efficiency of desflurane reflection in two commercially available reflectors.

With the AnaConDa™ and the MIRUS™ system, volatile anesthetics can be administered for inhalation sedation in intensive care units. Instead of a circle system, both devices use anesthetic reflectors to save on the anesthetic agent. We studied the efficiency of desflurane reflection with both devices using different tidal volumes (VT), respiratory rates (RR), and 'patient' concentrations (CPat) in a bench study. A test lung was ventilated with four settings (volume control, RR × VT: 10 × 300 mL, 10 × 500 mL, 20 × 500 mL, 10 × 1000 mL). Two different methods for determination of reflection efficiency were established: First (steady state), a bypass flow carried desflurane into the test lung (flowin), the input concentration (Cin) was varied (1-17 vol%), and the same flow (flowex, Cex) was suctioned from the test lung. After equilibration, CPat was stored online and averaged; efficiency [%] was calculated [Formula: see text]. Second (washout), flowin and flowex were stopped, the decline of CPat was measured; efficiency was calculated from the decay constant of the exponential regression equation. Both measurement methods yielded similar results (Bland-Altman: bias: -0.9 %, accuracy: ±5.55 %). Efficiencies higher than 80 % (>80 % of molecules exhaled are reflected) could be demonstrated in the clinical range of CPat and VT. Efficiency inversely correlates with the product of CPat and VT which can be imagined as the volume of anesthetic vapor exhaled by the patient in one breath, but not with the respiratory frequency. Efficiency of the AnaConDa™ was higher for each setting compared with the MIRUS™. Desflurane is reflected by both reflectors with efficiencies high enough for clinical use.

A technical review of the history, development and performance of the anaesthetic conserving device "AnaConDa" for delivering volatile anaesthetic in intensive and post-operative critical care.

There is a shift in critical care to adopt volatile anaesthetics as sedatives for certain patients using mechanical ventilation. Accompanying this shift is a growing body of literature describing the advantages or disadvantages of using isoflurane or sevoflurane for long term sedation. This practise requires a cost effective, efficient and safe means to deliver these drugs that can simultaneously operate with modern critical care ventilators and ventilation protocols while protecting the care environment and care workers from excessive exposure to the drugs. The anaesthetic conserving device ("AnaConDa", Sedana Medical) is one device that delivers a safe sedative dose of either isoflurane or sevoflurane to a patient using existing critical care ventilators, common syringe pumps and gas monitors. The device is essentially a small disposable anaesthetic vaporizer and HME filter combined into one airway component. Similar to an HME filter, the device reflects moisture back to the patient, but also reflects 90% of the anaesthetic by adsorbing and releasing the drug using a proprietary carbon filament reflecting medium. This reflection reduces the total amount of anaesthetic needed, reducing that which is exhausted or scavenged upon exhalation. It can be used for 24 h of sedation, and fits into current critical care ventilator circuits almost without modifications. This article will describe the physical characteristics of the device, how it works, its development history and the performance parameters under which it can be used.

[New technical developments for inhaled sedation]. / Neue technische Entwicklungen der inhalativen Sedierung.

The circle system has been in use for more than 100 years, whereas the first clinical application of an anaesthetic reflector was reported just 15 years ago. In the circle system, all breathing gas is rebreathed after carbon dioxide absorption. A reflector, on the other hand, with the breathing gas flowing to and fro, specifically retains the anaesthetic during expiration and resupplies it during the next inspiration. A high reflection efficiency (number of molecules resupplied/number of molecules exhaled, RE 80-90%) decreases consumption. In analogy to the fresh gas flow of a circle system, pulmonary clearance ((1-RE) × minute ventilation) defines the opposition between consumption and control of the concentration.It was not until reflection systems became available that volatile anaesthetics were used routinely in some intensive care units. Their advantages, such as easy handling, and better ventilatory capabilities of intensive care versus anaesthesia ventilators, were basic preconditions for this. Apart from AnaConDa™ (Sedana Medical, Uppsala, Sweden), the new MIRUS™ system (Pall Medical, Dreieich, Germany) represents a second, more sophisticated commercially available system.Organ protective effects, excellent control of sedation, and dose-dependent deep sedation while preserving spontaneous breathing with hardly any accumulation or induction of tolerance, make volatile anaesthetics an interesting alternative, especially for patients needing deep sedation or when intravenous drugs are no longer efficacious.But obviously, the outcome is most important. We know that deep intravenous sedation increases mortality, whereas inhalational sedation could prove beneficial. We now need prospective clinical trials examining mortality, but also the psychological outcome of those most critically ill patients sedated by inhalation or intravenously.