Pump Placement Research Articles

Perioperative and Oncologic Outcomes of Hepatic Arterial Infusion (HAI) Pump Chemotherapy for Patients with Unresectable Colorectal Liver Metastases at an Expanding HAI Program.

Hepatic arterial infusion (HAI) is an established treatment for patients with unresectable colorectal liver metastases (uCRLM). Until recently, HAI was only performed at a limited number of centers. We previously reported early outcomes suggesting that implementation of a new HAI program is safe and feasible. Here, we report perioperative and oncologic outcomes from an expanded series of patients with uCRLM treated with HAI. We analyzed outcomes from consecutive patients with uCRLM who underwent HAI pump (HAIP) placement at Duke University Hospital from 2018 to 2023. Demographics, prior treatment, and perioperative and oncologic outcomes were assessed. Overall, 102 patients underwent HAIP placement for uCRLM; 62% were male and median age was 51years. Most patients (97%) received a median of 12 (range 0-66) prior chemotherapy cycles. Postoperative HAI-specific complications occurred in 23% of patients, including biliary sclerosis in 6%, and the 90-day mortality rate was 3%. 20% converted to resection, 4% underwent transplant, and 2% achieved complete response at 6 months after floxuridine initiation. Median hepatic and extrahepatic progression-free survival (PFS) was 15.7 months and 11.6 months, respectively. Median overall survival (OS) was 38 months from the time of pump implantation (median follow-up time: 30 months). HAI for uCRLM is safe, feasible, and effective at a new center, with outcomes that recapitulate those previously reported by established centers. Future analysis of our institutional data, which includes mutation status, primary tumor sidedness, and extent of prior therapy could inform selection and treatment strategies for new HAI programs.

Process integration and electrification through multiple heat pumps using a Lorenz efficiency approach

This paper introduces a novel method for targeting the minimum shaft work required for process electrification employing principles of Pinch Analysis and detailed heat pump performance estimations. The method deviates from conventional Pinch Analysis by dividing the grand composite curve (GCC) into net heat sink and source profiles to enable the placement of heat pumps exploiting the heat pockets of the GCC. Additionally, it employs Lorenz efficiency over exergy efficiency, offering an accurate description of heat pump performance and highlighting the importance of integration between processes. The method is applied to two case studies. The first case, milk evaporator, focused on the placement of heat pumps in the heat pockets of the GCC. The results showed that while the maximum direct heat recovery was 20,447 kW, the optimal configuration limited the heat recovery to 12,199 kW, reducing the shaft work from 1,930 kW to 1,010 kW. The second, a spray dryer case, focused on the integration of electric boilers and the partial process electrification when available excess heat is limited. In this case, 1,520 kW out of 4,640 kW were covered by an electric boiler, with a biomass boiler replacing the electric boiler to cover 3,570 kW if available.

Selective dorsal rhizotomy after baclofen intrathecal pump removal: a single-center experience and review of the literature.

Selective dorsal rhizotomy (SDR) and intrathecal baclofen (ITB) pump placement are two surgical options in children affected by spasticity secondary to cerebral palsy 1. The latest literature is an enlarging indication for SDR in case of ITB failure in non-ambulant patients as an alternative to pump reimplantation to reduce spasticity and facilitate patients' care. A retrospective single-center study has screened all children diagnosed with spastic tetraparesis who underwent in the last 10 years SDR and had previously ITB pump implanted. A cohort of six patients was pooled out. Furthermore, pertinent literature has been reviewed. Indication for pump removal was pump pocket infection, parents' decision, and poor response to ITB. Patients' amount of lifetime with the pump implanted has been 6.9 years. The preoperative and postoperative Ashworth scores were statistically different in both procedures (p = 0.005 and p = 0.,02). Only two studies investigated the pediatric population undergoing SDR in the occurrence of ITB pump removal. Authors are offering SDR to all children, regardless of GMFCS groups and previous ITB pump placement.In conclusion, SDR represents a valid tool in neurosurgeon's hands to help ameliorate patients' long-lasting quality of life, reducing the severity of the spasticity and leading to better management by caregivers.

Peritoneal baclofen pump migration: a rare complication of subfascial placement. Illustrative cases.

The intrathecal baclofen pump is an effective treatment option for patients with severe spasticity. In children, subfascial pump placement is often preferred given concerns for infection and wound healing. However, this approach is not without risk, and rare complications, such as peritoneal pump migration, can occur. The authors describe three pediatric cases of peritoneal pump migration at their institution over the past 14 years (3/545, 0.5%). All three patients had low body weight (below the 39th percentile), and two had scoliosis requiring surgery. All pumps had been placed using the subfascial technique. The first case occurred 6 months postplacement, and the pump was not replaced. Cases 2 and 3 occurred at 2 and 3 years postplacement, respectively, and both pumps were replaced. The authors conclude that peritoneal pump migration, although uncommon, can occur in patients with subfascial pump placement, and providers should have a low threshold of suspicion for repeat imaging prior to refilling if the pump's location has migrated. Potential contributing factors to pump migration include a patient's small size, a larger pump size (40-mL pump), and scoliosis. All these factors should be considered during pump placement, and surgeons can consider using a 20-ml pump for smaller patients. https://thejns.org/doi/abs/10.3171/CASE24290.

Indocyanine green fluorescence perfusion testing in robot-assisted hepatic arterial infusion pump placement

BackgroundHepatic arterial infusion pump (HAIP) treatment is a technique used to treat liver localized malignancy with intra-arterial chemotherapy. Methylene blue is generally administered to verify hepatic perfusion and exclude inadvertent extrahepatic perfusion. The use of indocyanine green dye (ICG) combined with near-infrared (NIR) fluorescence imaging during robot-assisted HAIP placement may be an attractive alternative by providing high contrast without blue discoloration of the operative field.MethodsData was collected retrospectively from 2 centers in the Netherlands. Intraoperative perfusion of the liver segments and extrahepatic perfusion were assessed using ICG/NIR as well as methylene blue on video imaging and correlated to postoperative 99 m-Tc perfusion scintigraphy.Results13 patients underwent robot-assisted surgery for HAIP placement; median length of stay was 4 days, complications occurred in 4 patients. Hepatic perfusion showed identical patterns when ICG was compared with methylene blue. In 1 patient, additional extrahepatic perfusion was found using ICG, leading to further vessel ligation. Intraoperative ICG perfusion was concordant with 99 m-Tc perfusion scintigraphy.DiscussionLiver and extrahepatic perfusion determined by ICG fluorescence imaging is concordant with blue dye perfusion and 99 m-Tc perfusion scintigraphy. Therefore, ICG fluorescence imaging is deemed a safe and reliable technique for perfusion testing during robot-assisted HAIP placement.Graphical abstract

Reduction in Balloon Pump Size Reduces Axillary Intraaortic Balloon Pump Failure Risk.

Axillary artery intra-aortic balloon pump (axIABP) placement has been implemented as a bridging solution before heart transplantation. This study evaluates complications associated with axIABP support and describes an approach to minimize adverse events. We previously described a percutaneous approach for axIABP placement. However, patients receiving axIABP between September 1, 2017, and September 26, 2019 (n = 32) demonstrated a high rate of balloon pump malfunction (8/32; 25%) and other complications (totaling 15/32; 47%). Sixty-four patients were sequentially treated under a revised protocol. Compared to the initial cohort, no significant differences in demographics were noted. A significant reduction in rate of balloon malfunction (8/32, 25% vs. 1/64, 2%; p < 0.001) and total complications (15/32, 47% vs. 10/64, 16%; p = 0.0025) during the period of support were noted after intervention. Subsequent analysis of total complications per device size (40 vs. ≤ 34 ml balloon) revealed significantly reduced complications in patients with smaller devices (40% vs. 13%, respectively; p = 0.0022). This study provides guidelines to limit complications in patients supported with axIABP, facilitating a protracted period of bridging support.

Management of Cerebrospinal Fluid Leak After Intrathecal Baclofen Pump Procedures in Adolescents With Cerebral Palsy: A Retrospective Study.

Epidural blood patches (EBPs) are frequently performed in children with cerebral palsy (CP) to manage post-dural puncture headache (PDPH) due to cerebrospinal fluid (CSF) leak after intrathecal baclofen pump (ITBP) placement or replacement procedures. The purpose of our study was to review the incidence and management of CSF leak following ITBPplacement or replacement procedures in children with CP. The study was a retrospective review of 245 patients representing 310 surgical cases of baclofen pump insertion (n=141) or reinsertion (n=169) conducted at a 125-bed children's hospital with prominent specialty orthopedics surgical cases. Demographic and clinical information was obtained from the anesthesia pain service database on all new ITBP placement and subsequent replacements over an eight-year period. The overall incidence of CSF leak in our population was 16% (50 of 310) and 18% (25 of 141) with a new ITBP placement.Children with diplegia were associated with a threefold risk of developing CSF leak. Of patients who developed CSF leak (n=50), 68% (n=34) were successfully treated conservatively, while 32% (n=16) required EBPs.EBPs were successful in 87.5% (14 of 16) of patients at relieving PDPH on the first attempt. Conclusions:CSF leak is a known problem after ITBP placement and replacement. Most patients were successfully treated with conservative management and EBPs were successful in patients failing conservative therapy.Diagnosing PDPH in non-verbal patients can be challenging.

Safety and Efficacy of Surgical Implantation of Intrathecal Drug Delivery Pumps in Patients With Cancer With Refractory Pain.

Pain management in patients with cancer is a critical issue in oncology palliative care as clinicians aim to enhance quality of life and mitigate suffering. Most patients with cancer experience cancer-related pain, and 30%-40% of patients experience intractable pain despite maximal medical therapy. Intrathecal pain pumps (ITPs) have emerged as an option for achieving pain control in patients with cancer. Owing to the potential benefits of ITPs, we sought to study the long-term outcomes of this form of pain management at a cancer center. We retrospectively reviewed medical records of all adult patients with cancer who underwent ITP placement at a tertiary comprehensive cancer center between 2013 and 2021. Baseline characteristics, preoperative and postoperative pain control, and postoperative complication rate data were collected. A total of 193 patients were included. We found that the average Numerical Rating Scale (NRS) score decreased significantly by 4.08 points (SD = 2.13, P < .01), from an average NRS of 7.38 (SD = 1.64) to an average NRS of 3.27 (SD = 1.66). Of 185 patients with preoperative and follow-up NRS pain scores, all but 9 experienced a decrease in NRS (95.1%). The median overall survival from time of pump placement was 3.62 months (95% CI: 2.73-4.54). A total of 42 adverse events in 33 patients were reported during the study period. The 1-year cumulative incidence of any complication was 15.6% (95% CI: 10.9%-21.1%) and for severe complication was 5.7% (95% CI: 3.0%-9.7%). Eleven patients required reoperation during the study period, with a 1-year cumulative incidence of 4.2% (95% CI: 2.0%-7.7%). Our study demonstrates that ITP implantation for the treatment of cancer-related pain is a safe and effective method of pain palliation with a low complication rate. Future prospective studies are required to determine the optimal timing of ITP implantation.

Early and mid-term outcomes of minimally invasive mitral valve surgery in high operative risk patients at University Medical Center, Ho Chi Minh City

Introduction: Minimally invasive mitral valve surgery (MIMVS) has seen significant advancement in the past decades, offering numerous benefits to patients. However, there remain cohorts of patients with mitral valve pathologies, deemed at higher surgical risk, who may face rejection for MIMVS due to concerns regarding potential postoperative complications associated with this approach. Objective: To assess early and midterm outcomes of MIMVS in higher-operative-risk patients at the University Medical Center of Ho Chi Minh City. Methods: A retrospective descriptive study of the patients meeting our high operative risk criteria, who underwent mitral valve surgery at the University Medical Center of Ho Chi Minh City from January 2017 to March 2023. Results: A total of 68 eligible cases were included in our study. The male-to-female ratio was 0.6:1. Among these cases, 21 patients underwent valve repair and 47 others underwent mitral valve replacement. 30.9% of cases presented with NYHA class III or above heart failure. The mean cardiopulmonary circulation time and aortic cross-clamp time were 157.4 ± 38.8 minutes and 102.7 ± 26.3 minutes, respectively. Three cases experienced minimally invasive surgery related complications, including one case of limb ischemia requiring fasciotomy, one case of femoral wound seroma, and one case of postoperative wound infection necessitating debridement. No instances of conversion to sternotomy or in-hospital mortality were observed. The mean ICU stay and postoperative length of stay at ward were 4.6 ± 3.5 days and 10.8 ± 5.9 days, respectively. Patients showed rapid recovery during the postoperative period. During ICU care, one patient suffered a non-disabling cerebrovascular accident, one case required continuous renal replacement therapy, three cases necessitated intra-aortic balloon pump placement, and three cases required reoperation due to hemorrhagic pleural effusion. During follow-up period, three patients died within 6 months, and another patient died after their surgery one year. Other patients had favorable outcomes at the time of discharge and at subsequent follow-up. Conclusion: Minimally invasive mitral valve surgeries highlight the feasibility and safety of minimally mitral valve surgery in higher-operative-risk patients.

491 Clinical and Radiographic Features of Mesenteric Ischemia after Intra-Aortic Balloon Pump Placement

OBJECTIVES/GOALS: Intra-aortic balloon pumps are commonly used as circulatory support in patients with critically reduced cardiac function. The goal of this study is to estimate the incidence of mesenteric ischemia as an understudied vascular complication and to describe the clinical and radiographic characteristics of patients experiencing this complication. METHODS/STUDY POPULATION: We will be conducting a retrospective analysis of the electronic medical records of all patients who underwent intra-aortic balloon pump (IABP) placement between October 2020 and April 2023 at our academic medical center to identify the incidence of mesenteric ischemia. We will describe the clinical course of these patients and characterize them based on demographic features and risk factors for vascular complications including medical comorbidities. Finally, we will assess available chest x-ray and thoracoabdominal CT imaging for adequacy of balloon tip positioning, concordance between balloon size and aortic dimensions, and compromise of any visceral arteries in patients who experienced mesenteric ischemia vs. those who did not. RESULTS/ANTICIPATED RESULTS: We anticipate approximately 150 patients to have recieved IABPs over this period with at least 4 known cases of mesenteric ischemia. We will describe the clinical presentation of these cases and their often fatal outcomes. We expect several known risk factors will be present in these patients, including history of peripheral vascular disease, diabetes, or smoking history. On chest x-ray, we predict balloon tip positioning to be suboptimal (defined as &gt;5cm below the aortic arch) in many patients, both those with mesenteric ischemia and those without, but a greater discordance on CT imaging between balloon size and aortic dimensions with greater evidence of visceral compromise in patients with mesenteric ischemia compared to those without. DISCUSSION/SIGNIFICANCE: Mesenteric ischemia is a serious and poorly studied complication of intra-aortic balloon pumps. Understanding the hospital course, clinical characteristics, and radiographic features present in these patients may guide clinicians in the early recognition and management of this potentially fatal complication.

267 Risk Factors Associated With Baclofen Pump Infection in Children Translated Into Health-Care Costs: A Retrospective Analysis From the Children's Hospital of Pittsburgh Experience From 2009-2020

INTRODUCTION: Intrathecal baclofen infusion is often used as a therapy for spasticity in children and adults, with pediatric cases more associated with infections. Infection leads to the need for pump explantation and is associated with a significantly increased hospitalization cost. METHODS: We retrospectively reviewed demographic, clinical, and economic data for children who underwent surgery for intrathecal baclofen pumps at a single institution from 2009-2020. Bivariable analyses (chi-squared tests) were conducted to compare differences in clinical characteristics between patients with surgical site infection and those without. Mann-Whitney tests were performed to compare total charges per patient between patients who had an infection versus those who did not. RESULTS: A total of 199 patients undergoing 442 surgeries were included. The cohort was 64% male and 84% Caucasian, with a mean age of 13.3 years. The most common indication for placement was cerebral palsy. Infection occurred in 28 patients (14% infection rate). The most common organisms were methicillin-resistant and methicillin-sensitive staph aureus. The pump model, access site, and the number of surgeons scrubbed were not associated with infection. Total hospital charges (for all surgeries) were significantly higher for patients with an infection versus those who did not ($231,762 vs. $187,028, p=0.0078), with an average charge increase of $44,734 associated with surgical site infection. CONCLUSIONS: In our single-center series, the most common indication for baclofen pump placement was cerebral palsy, with an infection rate of 14%, close to other rates reported in the literature. Total hospital charges were higher for patients with an associated surgical site infection than those without one.

Manual Dexterity Predictors of Artificial Urinary Sphincter Success

ObjectiveTo determine better in-office measures for artificial urethral sphincter outcomes, we investigated the ability of preoperative timed peg-transfer, pinch strength, grip strength, and Disabilities of the Arm Shoulder and Hand Outcome questionnaire in predicting postoperative satisfaction, confidence, and ease of use of artificial urethral sphincter placement for stress urinary incontinence. Materials and MethodsA timed 9-hole peg test, pinch and grip strength assessment, and upper extremity questionnaire were administered during the preoperative visit before sphincter placement. In addition to standard preoperative workup, short form International Consultation of Incontinence Questionnaire and physician handshake were recorded. Activation occurred 6 weeks after surgery along with assessment of adequacy of pump placement. Three months from surgery a repeat incontinence questionnaire and a survey measuring satisfaction, difficulty of use, and confidence were given. Correlation between preoperative assessment variables and the postoperative questionnaire was assessed. ResultsThirty-nine patients were included. Average age and body mass index were 68.8 years and 28.8 kg/m2 respectively. Prior prostatectomy accounted for 92.3% of patients, and 46.2% had prior pelvic radiation. Postoperatively 59.0% of patients were very satisfied; 64.1% of patients reported no difficulty of use; 53.8% felt confidence within one day; and 66.7% had much better bladder control. Average pad improvement count was 5.3. Pinch test was associated with satisfaction (p= 0.011) while peg test was associated with confidence (p = 0.049). Handshake and upper extremity questionnaire were not significant. ConclusionsThe pinch and 9-hole peg transfer tests are cost-effective and easily performed adjuncts that could be used during artificial urethral sphincter evaluation for patients with unclear manual functional status.

Utilizing combination intrathecal baclofen and analgesic medication to manage spasticity and pain in patients with pediatric-onset disability: Case series.

The use of intrathecal medications for the management of spasticity and various pain syndromes in the adult population has been previously reported. However, no evidence-based guidelines currently exist in the pediatric population. This case series presents patients (n = 8) with pediatric-onset disability who underwent placement of intrathecal baclofen pumps initially for management of severe spasticity. Despite titration of dose and use of oral analgesia, their uncontrolled pain persisted. Each patient was transitioned to a combination of baclofen and analgesic intrathecal therapy. The outcome in pain improvement and quality of life, as reported by patients and/or caregivers, were retrospectively reviewed. Retrospective review of the background and decision-making process regarding transition to combination intrathecal therapy identified patient selection characteristics. Each patient and/or their caregivers completed a survey regarding improvements in pain, spasticity, function, and quality of life following initiation of combination intrathecal medications. Survey results revealed improvements in functional and pain assessments after initiation of combination baclofen and analgesic intrathecal medication. Patients and caregivers reported decreases in pain and oral spasticity medications. Use of pumps with antispasmodic and analgesic medication for combination intrathecal medication delivery should be considered in the management of patients with childhood-onset disabilities who have both severe spasticity and pain.

Expansion of the Subcutaneous Compartment by Umbilicus Resection for Intrathecal Pump Placement: The "Karagoz-Hacivat Technique".

Intrathecal baclofen (ITB) for severe spasticity can encounter complications such as wound dehiscence and ulcers because of elevated intracompartmental pressure within the abdominal subcutaneous and subfascial pocket housing the pump. We propose an innovative technique to manage ITB wound ulcers. Resecting the umbilicus create a more spacious and less tension-prone pocket for the ITB pump. Between 2015 and 2023, we implanted ITB pumps in 65 patients. Among them, 5 patients presented with skin ulcer or dehiscence underwent surgery using the novel technique. Postoperative follow-up revealed successful wound healing, with no further wound-related complications. The proposed technique provides effective and practical solution to wound and skin complications related to ITB pump. Moreover, it may serve as a viable preemptive strategy during the initial implantation of the ITB pump in selected patients.

Efek tinggi hisap terhadap kapasistas pompa sentrifugal

Centrifugal pumps are one type of pump commonly used in the industry, particularly in the processing and distribution of clean water. The characteristics of these pumps can be determined by varying the flow rate at a certain height. A study was conducted to investigate the effects of three different pump heights (3.5 m, 4.5 m, and 5.5 m) on the efficiency of a centrifugal pump using water at a temperature of 31℃. The results showed that the maximum overall efficiency was obtained at a height of 4.5 m with a value of 33.22% and a total head of 23.39 m. The pump height was found to have an impact on the pump capacity, with higher pump positions resulting in an increased occurrence of cavitation bubbles in the suction pipe, leading to a decrease in pump performance. Therefore, the placement of centrifugal pumps should be carefully considered, taking into account factors such as height and distance of the suction pipe, to minimize cavitation and achieve optimal pump performance.

Recurrence patterns after complex multimodality therapy and hepatic arterial infusion for colorectal liver metastases: A reflection of biology and technique.

We characterized colorectal liver metastasis recurrence and survival patterns after surgical resection and intraoperative ablation ± hepatic arterial infusion pump (HAIP) placement. We estimated patterns of recurrence and survival in patients undergoing contemporary multimodal treatments. Between 2017 and 2021, patient, tumor characteristics, and recurrence data were collected. Primary outcomes included recurrence patterns and survival data based on operative intervention. There were 184 patients who underwent hepatectomy and intraoperative ablation. Sixty patients (32.6%) underwent HAIP placement. A total of 513 metastases were ablated, median total of 2 ablations per patient. Median time to recurrence was 31 [22-40] months. Recurrence patterns included tumor at ablative margin on first scheduled postoperative imaging (8, 4.3%), local tumor recurrence at ablative site (69, 37.5%), and non-ablated liver tumor recurrence (38, 20.6%). In patients who underwent HAIP placement, the rate of liver recurrence was reduced (45% vs 70.9%, p = 0.0001). Median overall survival was 64 [41-58] months and prolonged survival was associated with HAIP treatment (85 [66-109] vs 60 [51-70] months. Hepatic recurrence is common and combination of intraoperative ablation and HAIP treatments were associated with prolonged survival. These data may reflect patient selection however, future work will clarify preoperative tumor and patient characteristics that may better predict recurrence expectations.

Extrahepatic perfusion and incomplete hepatic perfusion after hepatic arterial infusion pump implantation: incidence and clinical implications

IntroductionThis study investigates the incidence of extrahepatic perfusion and incomplete hepatic perfusion at intraoperative methylene blue testing and on postoperative nuclear imaging in patients undergoing hepatic arterial infusion pump (HAIP) chemotherapy. MethodsThe first 150 consecutive patients who underwent pump implantation in the Netherlands were included. All patients underwent surgical pump implantation with the catheter in the gastroduodenal artery. All patients underwent intraoperative methylene blue testing and postoperative nuclear imaging (99mTc-Macroaggregated albumin SPECT/CT) to determine perfusion via the pump. ResultsPatients were included between January-2018 and December-2021 across eight centers. During methylene blue testing, 29.3% had extrahepatic perfusion, all successfully managed intraoperatively. On nuclear imaging, no clinically relevant extrahepatic perfusion was detected (0%, 95%CI: 0.0–2.5%). During methylene blue testing, 2.0% had unresolved incomplete hepatic perfusion. On postoperative nuclear imaging, 8.1% had incomplete hepatic perfusion, leading to embolization in only 1.3%. ConclusionMethylene blue testing during pump placement for intra-arterial chemotherapy identified extrahepatic perfusion in 29.3% of patients, but could be resolved intraoperatively in all patients. Postoperative nuclear imaging found no clinically relevant extrahepatic perfusion and led to embolization in only 1.3% of patients. The role of routine nuclear imaging after HAIP implantation should be studied in a larger cohort.

Opening Pressure and Post-Lumbar Puncture Headache in Children Undergoing Intrathecal Baclofen Trial.

Aims: Post-lumbar puncture headache occurs in 5% to 12% of children. The purpose of this study was to determine the frequency and predictors of post-lumbar puncture headache in children with hypertonia undergoing lumbar puncture for intrathecal baclofen trial. Methods: This was a retrospective single-center review of all 43 children (<18 years) with hypertonia and/or dyskinesia undergoing intrathecal baclofen trial from 2013-2022. Predictors of post-lumbar puncture headache were evaluated via 2-way paired t test and Fisher exact test. Results: Seven subjects (16.3%) developed post-lumbar puncture headache. Of patients who developed post-lumbar puncture headache, 3 required emergency care or hospitalization. One was misdiagnosed with constipation. The 16 patients without opening pressure measured were excluded from subsequent analyses. Of the 27 patients with documented opening pressure, the mean opening pressure was 24.0 cm H2O (SD 6.5) and 5 (18.5%) had elevated opening pressure (>28 cm H2O). Mean opening pressure was higher for those with post-lumbar puncture headache (28.6 vs 22.4 cm H2O, P = .014). Sixty percent of patients with elevated opening pressure developed post-lumbar puncture headache. Baclofen pumps were placed in 4 (80%) patients with elevated opening pressure and 6 (85.7%) with post-lumbar puncture headaches without complications. Interpretation: The risk of post-lumbar puncture headache after intrathecal baclofen trial was higher than reported in the literature, likely because of greater rates of elevated opening pressure. Physicians may use opening pressure to predict risk for post-lumbar puncture headache and should educate families about symptoms. Elevated opening pressure or post-lumbar puncture headache may not preclude baclofen pump placement.

Modelling of Cryopumps for Space Electric Propulsion Usage

Electric space propulsion is a technology that is used in a continuously increasing number of spacecrafts. The qualification of these propulsion systems has to run in ground-based test facilities which requires long testing times and powerful pumping systems. In these usually large test facilities, high pumping speeds are achieved with cryopumps. Cryopump operation is very expensive with respect to electrical energy and cooling water consumption. Therefore, being able to optimize pump shape, cold plate material, and pump placement in a chamber is beneficial. Pump design and tuned operating strategies can reduce costs and increase intervals between regeneration. Testing different pump configuration setups in a large facility is mostly prohibitive due to high costs and long testing times. Optimization via modelling is a better choice for design and also, later, for operation. Therefore, having a numerical model and proven guidelines at hand for optimization is very helpful. This paper describes a new model developed at DLR for the optimization of cryopump layout and operation. Model results are compared with cryopump operational and warm-up data. This validation is the basis for further optimization actions like multi-layer insulation layouts and pump cold plate upgrades, and helps in understanding and mitigating the detrimental effect of water condensates on the cryopump cold plates.

A phase II trial of induction systemic mFOLFIRINOX followed by hepatic arterial infusion of floxuridine and dexamethasone given concurrently with systemic mFOLFIRI as a first-line therapy in patients with unresectable liver-dominant intrahepatic cholangiocarcinoma (HELIX-1).

511 Background: Most patients with intrahepatic cholangiocarcinoma (ICC) have unresectable or multifocal liver-dominant disease. Survival after first-line systemic therapy remains poor, with median progression-free (mPFS) and overall survival of 7.2 and 12.8 months, respectively. Hepatic arterial infusion (HAI) therapy with floxuridine maximizes liver-specific treatment with minimal systemic toxicity and potentially offers improved disease control when combined with systemic therapy. Methods: HELIX-1 (NCT04251715) is an investigator-initiated, first-line, single-center, single-arm phase II clinical trial for patients with liver-dominant unresectable or multifocal ICC. The trial was designed with a patient safety run-in evaluating toxicity from the combined therapy. Pre-trial screening included laparoscopy, biopsies, and PET/CT. Eligible patients were treated with systemic mFOLFIRINOX for 4 cycles in order to select those likely to benefit from HAI. Patients with disease control on restaging proceeded to HAI pump placement and treatment with HAI floxuridine for 14 days followed by systemic mFOLFIRI on a 28-day cycle. The co-primary objectives were to assess safety of the combined therapeutic strategy and the disease control rate (DCR) at 6 months (RECIST v1.1) at end of trial (EOT). Results: A total of n=5 patients with liver-only ICC enrolled in the trial and completed the entire study protocol. The median age was 60 years (range 42-69) with a dominant lesion size of 9.8cm (range 8.4-14.5). All patients had both right and left hemiliver involvement with a median of 9 intrahepatic tumors (range 1-15). No patients experienced grade 3 or 4 adverse events, or hepatic dysfunction leading to cessation of HAI therapy. The DCR at 6 months was 100%, with a mPFS of 18.2 months. All five patients achieved partial radiographic response (PR) while receiving HAI therapy, and remain alive with liver-only disease at a median of 18.4 months (range 12.7-20) after study enrollment. After continuing treatment with HAI and systemic mFOLFIRI beyond the EOT, two patients transitioned to HAI treatment only and then to biochemical and radiographic surveillance without therapy after demonstrating PR and CA19-9 normalization. Conclusions: Integration of HAI floxuridine with mFOLFIRI following mFOLFIRINOX induction for patients with liver-only advanced ICC is well-tolerated and demonstrates longer DCR in comparison to historical controls. The combined regimen minimized systemic toxicity and allowed a large proportion of patients to transition to liver-only HAI treatment with maintained disease control. Future directions include combining HAI with new first-line systemic regimens for patients with advanced ICC. Clinical trial information: NCT04251715 .