Performance and safety of femoral central venous catheters in pediatric autologous peripheral blood stem cell collection

INTRODUCTION

Autologous peripheral blood hematopoietic progenitor cell collection (A-HPCC) in children typically requires placement of a central venous catheter (CVC) for venous access. There is scant published data regarding the performance and safety of femoral CVCs in pediatric A-HPCC.

METHODS

Seven-year, retrospective study of A-HPCC in pediatric patients collected between 2009 and January 2017. Inclusion criteria were an age ≤ 21 years and A-HPCC using a femoral CVC for venous access. Femoral CVC performance was examined by CD34 collection rate, inlet rate, collection efficiency (MNC-FE, CD34-FE), bleeding, flow-related adverse events (AE), CVC removal, and product sterility testing. Statistical analysis and graphing were performed with commercial software.

RESULTS

A total of 75/119 (63%) pediatric patients (median age 3 years) met study criteria. Only 16% of children required a CVC for ≥ 3 days. The CD34 collect rate and CD34-FE was stable over time whereas MNC-FE decreased after day 4 in 80% of patients. CD34-FE and MNC-FE showed inter- and intra-patient variability over time and appeared sensitive to plerixafor administration. Femoral CVC showed fewer flow-related AE compared to thoracic CVC, especially in pediatric patients (6.7% vs. 37%, P = 0.0005; OR = 0.12 (95%CI: 0.03-0.45). CVC removal was uneventful in 73/75 (97%) patients with hemostasis achieved after 20-30 min of pressure. In a 10-year period, there were no instances of product contamination associated with femoral CVC colonization.

CONCLUSION

Femoral CVC are safe and effective for A-HPCC in young pediatric patients. Femoral CVC performance was maintained over several days with few flow-related alarms when compared to thoracic CVCs.

Comparison of different platelet transfusion thresholds prior to insertion of central lines in patients with thrombocytopenia

BACKGROUND

Patients with a low platelet count (thrombocytopenia) often require the insertion of central lines (central venous catheters (CVCs)). CVCs have a number of uses; these include: administration of chemotherapy; intensive monitoring and treatment of critically-ill patients; administration of total parenteral nutrition; and long-term intermittent intravenous access for patients requiring repeated treatments. Current practice in many countries is to correct thrombocytopenia with platelet transfusions prior to CVC insertion, in order to mitigate the risk of serious procedure-related bleeding. However, the platelet count threshold recommended prior to CVC insertion varies significantly from country to country. This indicates significant uncertainty among clinicians of the correct management of these patients. The risk of bleeding after a central line insertion appears to be low if an ultrasound-guided technique is used. Patients may therefore be exposed to the risks of a platelet transfusion without any obvious clinical benefit.

OBJECTIVES

To assess the effects of different platelet transfusion thresholds prior to the insertion of a central line in patients with thrombocytopenia (low platelet count).

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in CENTRAL (The Cochrane Library 2015, Issue 2), MEDLINE (from 1946), EMBASE (from 1974), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 23 February 2015.

SELECTION CRITERIA

We included RCTs involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in patients of any age with thrombocytopenia requiring insertion of a CVC.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

One RCT was identified that compared different platelet transfusion thresholds prior to insertion of a CVC in people with chronic liver disease. This study is still recruiting participants (expected recruitment: up to 165 participants) and is due to be completed in December 2017. There were no completed studies. There were no studies that compared no platelet transfusions to a platelet transfusion threshold.

AUTHORS' CONCLUSIONS

There is no evidence from RCTs to determine whether platelet transfusions are required prior to central line insertion in patients with thrombocytopenia, and, if a platelet transfusion is required, what is the correct platelet transfusion threshold. Further randomised trials with robust methodology are required to develop the optimal transfusion strategy for such patients. The one ongoing RCT involving people with cirrhosis will not be able to answer this review's questions, because it is a small study that assesses one patient group and does not address all of the comparisons included in this review. To detect an increase in the proportion of participants who had major bleeding from 1 in 100 to 2 in 100 would require a study containing at least 4634 participants (80% power, 5% significance).

Clinical impact of contrast-enhanced computed tomography combined with low-dose (18)F-fluorodeoxyglucose positron emission tomography/computed tomography on routine lymphoma patient management

This study evaluated the clinical impact of contrast-enhanced computed tomography (CECT) on routine management of patients with lymphoma. Over a 1-year period, 237 CECT scans were performed prospectively in 163 patients after low-dose (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT). Scans were performed at staging (n = 41), interim (n = 73), post-therapy (n = 115) and follow-up (n = 8). Clinical impact was determined from the multidisciplinary committee reports. CECT had no clinical impact in 219 cases (92%). A clear impact was noted in only 3%, i.e. up-staging of lymphoma (n = 2) and diagnosis of deep vein thrombosis (n = 5). A debatable impact was noted in the remaining 11 cases, consisting of additional investigations, either without therapeutic impact (n = 8), or resulting in delay of therapy onset (n = 2) or ablative surgery (n = 1). CECT delivered an average 33.5 ± 3.8 mSv vs. 17.7 ± 2.8 mSv for PET/CT. In conclusion, the clinical impact of CECT seems limited, although scarce, life-threatening conditions were diagnosed. Imaging of lymphoma needs optimization to reduce radiation exposure.

Thromboembolism following removal of femoral venous apheresis catheters in patients with breast cancer

BACKGROUND

Apheresis catheters have simplified collection of peripheral blood stem cells (PBSC), but may be associated with thrombosis of the instrumented vessels. We performed a retrospective analysis to study the prevalence of thromboembolism associated with the use of femoral apheresis catheters in patients with breast cancer.

PATIENTS AND METHODS

Patients were participants in clinical trials of high-dose chemotherapy with autologous PBSC rescue. They underwent mobilization with either high-dose cyclophosphamide (n = 21) or cyclophosphamide/paclitaxel (n = 64), followed by filgrastim. Double lumen catheters (12 or 13 Fr) were placed in the femoral vein and removed within 12 h of the last apheresis procedure. Apheresis was performed using a continuous flow cell separator and ACD-A anticoagulant. Thromboembolism was diagnosed by either venous ultrasonography or ventilation-perfusion scan.

RESULTS

Nine of 85 patients (10.6%) undergoing large volume apheresis with use of a femoral catheter developed thromboembolic complications. Pulmonary embolus (PE) was diagnosed in five and femoral vein thrombosis in four patients. Four of the five patients who developed PE were symptomatic; one asymptomatic patient had a pleural-based, wedge-shaped lesion detected on a staging computed tomography scan. The mean number of apheresis procedures was 2.4 (range one to four) and the mean interval between removal of the apheresis catheter and diagnosis of thrombosis was 17.6 days. In contrast, none of 18 patients undergoing apheresis using jugular venous access and none of 54 healthy allogeneic donors undergoing concurrent filgrastim-mobilized PBSC donation (mean 1.7 procedures/donor) using femoral access experienced thromboembolic complications.

CONCLUSIONS

Thromboembolism following femoral venous catheter placement for PBSC collection in patients with breast cancer may be more common than previously recognized. Healthy PBSC donors are not at the same risk. Onset of symptoms related to thrombosis tended to occur several weeks after catheter removal. This suggests that the physicians not only need to be vigilant during the period of apheresis, but also need to observe patients for thromboembolic complications after the catheter is removed. The long interval between the removal of apheresis catheter and the development of thromboembolism may have a potential impact on prophylactic strategies developed in future, such as the duration of prophylactic anticoagulation. Avoidance of the femoral site in breast cancer patients, and close prospective monitoring after catheter removal, are indicated.

Efficacy and safety of femoral vascular access for peripheral blood stem cell (PBSC) collection

Central venous catheters are frequently used in leukapheresis to provide high flow rates. The most common locations are the subclavian or jugular vein, but insertion-related complications and inadequate flow are frequent problems. Experience using femoral venous access is limited, because this has been discouraged due to the high incidence of infectious or thromboembolic complications. We evaluated the safety and efficacy of 108 short-term femoral venous dialysis catheters used for the collection of peripheral blood stem cells (PBSCs). All catheters were placed by a member of the dialysis unit, and they remained in situ for the days needed to reach the target number of CD34+cells. No prophylactic antibiotic or antithrombotic therapy was used. A total of 232 apheresis sessions was performed. The longest duration a catheter remained in situ was 5 days. Most of the patients finished the collection in one or two apheresis sessions. There were no thrombotic or infectious complications, and insertion-related complications or mechanical problems were minimal. Apheresis results were similar to those reported using subclavian or jugular venous access. The short-term use of femoral venous dialysis catheters appears safe and effective for PBSC collection, simplifying the procedure, improving patient comfort, and reducing cost.

Peripheral blood stem cell mobilization. A role for CXC chemokines

Chemokines induce rapid hematopoietic stem and progenitor cell mobilization and synergize with hematopoietic cytokines in mobilizing stem and progenitor cells. These proteins alone and in combination offer new paradigms for autologous and allogeneic peripheral blood stem cell transplantation (PBSCT). The mechanisms responsible for hematopoietic stem cell (HSC) mobilization either with growth factors or chemokines are largely unknown, but a better understanding of these mechanisms will permit the development of novel, more rapid and efficacious regimens. Studies presented herein indicate that the CXCR2 chemokine receptor that interacts with selective chemokine ligands, particularly GRObeta/CXCL2 and GRObeta-T, may be the dominant receptor mediating hematopoietic cell mobilization, and that polymorphonuclear neutrophils may be the primary CXCR2 expressing target cell for stem and progenitor cell mobilization.

Use of percutaneous radial artery catheter for peripheral blood progenitor cell collection in pediatric patients

BACKGROUND

Leukapheresis procedures require adequate flow rates, which in children may frequently involve invasive vascular access placement.

STUDY DESIGN AND METHODS

A minimally invasive peripheral radial artery catheter was used for drawing blood in 85 leukapheresis procedures performed in 33 pediatric patients. Blood return to the patients was provided by either a central Broviac-type catheter or a peripheral venous access. The patients' age range was 1 to 18 years (median, 9.5) and the weight range was 9 to 73 kg (median, 29 kg). Vasocan Braunüle Luer Lock IV cannulas (22 gauge in 78 and 20 gauge in 7) were placed percutaneously under local anesthesia, and in 8 patients, catheter placement was carried out during general anesthesia for other procedures. A continuous flow cell separator was used in all cases (Fresenius AS104 in 23 and AS204 in 62).

RESULTS

Flow rates ranged from 18 to 45 mL per minute, the mean number of total blood volumes processed was 2.07 (range, 0.51-2.51), and the mean duration of the procedures was 150 minutes (range, 90-260). The 22-gauge cannulas provided adequate flow rates independently of patient age and weight. No significant thrombotic, embolic, hemorrhagic, ischemic, or infectious complications were observed.

CONCLUSION

Peripheral radial artery catheters are safe, are minimally invasive, and provide steady, high-flow rates, and they should be considered for patients requiring leukapheresis and lacking a suitable vascular access for drawing blood.