Thrombogenicity of total parenteral nutrition solutions: I. Effect on induction of monocyte/macrophage procoagulant activity

High Rate of Venous Thromboembolism in Severe Pediatric Intestinal Failure

OBJECTIVE

To quantify the rate of venous thromboembolism (VTE) in patients with pediatric intestinal failure and identify associated risk factors.

STUDY DESIGN

We performed a retrospective cohort study in pediatric patients (<21 years old) with severe pediatric intestinal failure (≥90 consecutive days of parenteral nutrition) secondary to short bowel syndrome who were treated from 2014 to 2021 at an interdisciplinary intestinal rehabilitation program. The primary outcome was the incidence of VTE. Multivariable regression was performed to identify independent clinical predictors of VTE.

RESULTS

A total of 263 patients (59.7% male) met the criteria for inclusion. The cumulative incidence of VTE was 28.1%, with a rate of 0.32 VTEs per 1000 catheter-days. On univariate analysis, the number of catheter days, number of catheters, and history of central line-associated blood stream infection were associated with VTE. On multivariable logistic regression, a higher number of catheters was an independent risk factor for VTE (aOR, 1.17; 95% CI, 1.06-1.29). Additionally, earlier gestational age was a risk factor for VTE such that every week decrease in gestational age conferred a 9% increased risk of VTE (aOR, 1.09; 95% CI, 1.02-1.16).

CONCLUSIONS

In this retrospective study, 28.1% of patients with severe pediatric intestinal failure developed VTE; the number of catheters and early gestational age were noted to be independent risk factors for VTE. This high incidence of VTE highlights the need to investigate VTE in pediatric intestinal failure prospectively, including the potential benefit of prophylactic anticoagulation.

Intravenous lipid emulsion modifies synaptic transmission in hippocampal CA1 pyramidal neurons after bupivacaine-induced central nervous system toxicity

Local anesthetics can cause severe toxicity when absorbed systemically. Rapid intravenous administration of lipid emulsion (LE) is the standard of care for severe local anesthetic systemic toxicity which can cause cardiovascular and central nervous system (CNS) injury. The biological mechanism by which LE alleviates CNS toxicity remains unknown and understudied. Previous research has suggested that local anesthetics cause an imbalance of excitatory and inhibitory transmission in the brain. Therefore, this study aimed to observe the effect of LE on glutamate- and GABA-induced currents in CA1 pyramidal neurons after bupivacaine-induced CNS toxicity. We further characterized post-synaptic modifications in these cells to try to elucidate the mechanism by which LE mediates bupivacaine-induced CNS toxicity. Sprague-Dawley rats received intravenous bupivacaine (1 mg kg^-1  min^-1 ) in either normal saline or LE (or LE without bupivacaine) for 5 min. An acute brain slice preparation and a combination of whole-cell patch clamp techniques and whole-cell recordings were used to characterize action potential properties, miniature excitatory, and inhibitory post-synaptic currents, and post-synaptic modifications of excitatory and inhibitory transmission in CA1 hippocampal pyramidal neurons. The expression level of GABAA receptors were assessed with western blotting, whereas H&E and TUNEL staining were used to assess cytoarchitecture and apoptosis levels respectively. Bupivacaine treatment significantly increased the number of observed action potentials, whereas significantly decreasing rheobase, the first interspike interval (ISI), and hyperpolarization-activated cation currents (Ih) in CA1 pyramidal neurons. LE treatment significantly reduced the frequency of miniature inhibitory post-synaptic currents and enhanced GABA-induced paired pulse ratio with 50 ms interval stimulation in bupivacaine-treated rats. Regulation of GABAA levels is a promising mechanism by which LE may ameliorate CNS toxicity after systemic absorption of bupivacaine.

Characterizing the Risk Factors Associated With Venous Thromboembolism in Pediatric Patients After Central Venous Line Placement

OBJECTIVES

With the apparent increase in venous thromboembolism noted in the pediatric population, it is important to define which children are at risk for clots and to determine optimal preventative therapy. The purpose of this study was to determine the risk factors for venous thromboembolism in pediatric patients with central venous line placement.

METHODS

This was an observational, retrospective, case-control study. Control subjects were patients aged 0 to 18 years who had a central venous line placed. Case subjects had a central line and a radiographically confirmed diagnosis of venous thromboembolism.

RESULTS

A total of 150 patients were included in the study. Presence of multiple comorbidities, particularly the presence of a congenital heart defect (34.7% case vs. 14.7% control; p < 0.005), was found to put pediatric patients at increased risk for thrombosis. Additionally, the administration of parenteral nutrition through the central line (34.7% case vs. 18.7% control; p = 0.03) and location of the line increased the risk for clot formation.

CONCLUSIONS

With increased awareness of central venous line-related thromboembolism, measures should be taken to reduce the number and duration of central line placements, and further studies addressing the need for thromboprophylaxis should be conducted.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about antithrombotic therapy in neonates and children is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see Guyatt et al in this supplement, pages 123S-131S). In this chapter, many recommendations are based on extrapolation of adult data, and the reader is referred to the appropriate chapters relating to guidelines for adult populations. Within this chapter, the majority of recommendations are separate for neonates and children, reflecting the significant differences in epidemiology of thrombosis and safety and efficacy of therapy in these two populations. Among the key recommendations in this chapter are the following: In children with first episode of venous thromboembolism (VTE), we recommend anticoagulant therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1B]. Dosing of IV UFH should prolong the activated partial thromboplastin time (aPTT) to a range that corresponds to an anti-factor Xa assay (anti-FXa) level of 0.35 to 0.7 U/mL, whereas LMWH should achieve an anti-FXa level of 0.5 to 1.0 U/mL 4 h after an injection for twice-daily dosing. In neonates with first VTE, we suggest either anticoagulation or supportive care with radiologic monitoring and subsequent anticoagulation if extension of the thrombosis occurs during supportive care (Grade 2C). We recommend against the use of routine systemic thromboprophylaxis for children with central venous lines (Grade 1B). For children with cerebral sinovenous thrombosis (CSVT) without significant intracranial hemorrhage (ICH), we recommend anticoagulation initially with UFH, or LMWH and subsequently with LMWH or vitamin K antagonists (VKAs) for a minimum of 3 months (Grade 1B). For children with non-sickle-cell disease-related acute arterial ischemic stroke (AIS), we recommend UFH or LMWH or aspirin (1 to 5 mg/kg/d) as initial therapy until dissection and embolic causes have been excluded (Grade 1B). For neonates with a first AIS, in the absence of a documented ongoing cardioembolic source, we recommend against anticoagulation or aspirin therapy (Grade 1B).

Management of a small bowel transplant with complicated central venous access in a patient with asymptomatic superior and inferior vena cava obstruction

During the past few years, small bowel transplantation (SBT) has become a realistic alternative for patients with irreversible intestinal failure who have or will develop severe complications from total parenteral nutrition (TPN). Transplantation can be associated with large fluid shifts and massive blood loss necessitating rapid infusions of large quantities of crystalloid and/or blood products. Invasive monitoring and large-bore venous access are necessary in order to manage these patients intraoperatively. Because patients with irreversible intestinal failure are often managed with total parenteral nutrition via a central venous catheter, thrombotic intraluminal obstruction of major vessels may develop over time. Additionally, this may lead to superior vena cava (SVC) syndrome as well as challenging problems with vascular access. We present a 34-year-old woman with a past medical history for long-standing Crohn's disease with multiple small bowel resections and short gut syndrome who presented for an SBT. The patient had a long history of TPN use, complicated by SVC syndrome and inferior vena cava (IVC) obstruction. She was presently asymptomatic from her SVC obstruction. Central venous access was obtained by an interventional radiologist. A 7-French double-lumen Hickman minicatheter was placed in the left femoral vein with the tip of the catheter positioned just distal to the IVC narrowing. A left radial 20-gauge arterial line was placed for hemodynamic monitoring and frequent blood sampling. The patient's left and right dorsal-saphenous veins were cannulated with 16-guage catheters and adequate flow was observed. Lower extremity pressure was measured via the Hickman catheter in the left femoral vein. A multiplane transesophageal echo was used to assess ventricular volume. The options and intraoperative management of such patients are discussed.

Central venous catheter occlusion and thrombosis

Central venous catheters are widely used in children with critical illness and chronic disease. These devices are often essential in the delivery of medications and intravenous fluids and in hemodynamic monitoring. Central venous catheter occlusion and thrombosis are common problems in patients using these devices. This article reviews the background, pathophysiology, and incidence of catheter occlusion and catheter-related thrombosis. Diagnostic, preventive, and treatment strategies, along with future research directions, are addressed.

Assessment of distal tip position of long-term central venous feeding catheters using transesophageal echocardiology

BACKGROUND

Central vein catheter position is a vital element in promoting longevity and minimizing adverse events associated with long-term parenteral nutrition. Traditionally, position has been verified using a chest radiograph. However, this mode of assessment has limitations as the catheter is placed in a dynamic system subject to forces from changes in posture and diaphragmatic movement.

METHODS

We compared the reported position using a chest x-ray compared with assessment using transesophageal echocardiology (TOE) in 9 patients receiving home parenteral nutrition. The x-ray was reported by a radiologist unaware of the study.

RESULTS

There were discordant results in 7 of the 9 cases with catheter tip placed in the right atrium or impinging in the tricuspid valve which was not evident from the chest x-ray. TOE offered greater information of catheter tip position and relationship to adjacent anatomy.

CONCLUSIONS

Further work is required but this observational study suggests guidelines suggesting the use of a chest radiograph to confirm catheter position may need to be re-assessed.

Venous thromboembolic events in pediatric patients. Diagnosis and management

Venous thromboembolism is a rapidly increasing secondary complication in children being treated for serious, life-threatening, primary diseases. Most current management guidelines and recommendations for imaging techniques have been extrapolated from the results of trials in adults. This may be less than optimal for children as there are important differences. The purpose of this article is to summarize the information on venous thromboembolism in children, and offer some guidelines for diagnosis, prophylaxis, and therapeutic intervention based on the best available evidence.

Monitoring and complications of parenteral nutrition

A knowledge of the complications of parenteral nutrition is inherent in the design of any monitoring system. In the initial stages of therapy, the complications are usually of electrolyte imbalance. It must also be appreciated that the provision of nutrition to severely malnourished patients will expose underlying deficiencies, particularly of phosphates and trace elements. In long-term parenteral nutrition, the complications can be broadly divided into those associated with the line and metabolic complications. The line complications include: line blockage, sepsis, and pulmonary embolism. The most important metabolic complication is undoubtedly liver cholestasis, which may be associated with recurrent episodes of sepsis. Any department undertaking long-term parenteral nutrition should have an active nutrition team to avoid complications and audit outcome.

Incidence and risk factors of catheter-related deep vein thrombosis in a pediatric intensive care unit: a prospective study

OBJECTIVE

To estimate the incidence and to characterize risk factors for central venous catheter (CVC)-related deep vein thrombosis (DVT) in a pediatric intensive care unit.

STUDY DESIGN

Consecutive children admitted to a pediatric intensive care unit who required a CVC for more than 48 hours were examined by Doppler ultrasonography of the catheterized vein at days 2, 4, 6, or 7 after insertion and weekly thereafter until CVC removal.

RESULTS

The incidence of CVC-related DVT was 18.3% (17 of 93) (95% confidence interval = 10.2% to 25.8%). Thromboses were diagnosed within the first 4 days of catheter placement for 15 of 17 CVC-related thromboses. Multivariate analysis showed that risk factors most predictive of CVC-related DVT were presence of a cancer (odds ratio = 17.23, 95% confidence interval = 1.5 to 194) and young age (odds ratio for age = 0.72, 95% confidence interval = 0.54 to 0.96).

CONCLUSION

The frequency of CVC-related DVT is substantial in pediatric intensive care units. Risk is highest during the 4 days after insertion and decreases thereafter. The clinical impact, optimal prevention, and therapy of these thromboses remain to be determined.

Potential hazards of excluded bowel and use of parenteral nutrition: a case report

This case demonstrates that excluded gut may be a reservoir for bacterial translocation and recurrent sepsis. Translocation may contribute to cholestatic hepatitis, and restoration of bowel continuity is fundamental to reversing these pathologic changes. It also emphasizes that parenteral nutrition even when used as interim supportive treatment is not without serious hazard.

A cross-sectional study of catheter-related thrombosis in children receiving total parenteral nutrition at home

We performed a cross-sectional evaluation of deep vein thrombosis (DVT) related to the use of central venous lines (CVLs) in all pediatric patients receiving home total parenteral nutrition at our institution (N = 12). All children (5 months to 17 years of age) were examined with bilateral upper limb venography. All CVLs were flushed daily with heparin (200 units). At the time of evaluation, 49 CVLs had been placed in the 12 children. Of the 39 CVLs removed, 27 (66%) were blocked; venograms had not been previously obtained except of one child. Eight children had clinical evidence of superficial collateral circulation in the upper portion of the chest and the upper extremities; five had intermittent symptoms of superior vena cava obstruction. On venography, 8 of the 12 children had extensive evidence of DVT; two were unilateral and six bilateral. Five children were treated with warfarin (0.12 to 0.28 mg/kg per day) to achieve an international normalized ratio of 1.4 to 1.8. Neither bleeding nor further CVL-related DVT has occurred. We conclude that the risk of CVL-related DVT in children requiring home total parenteral nutrition is high, and that venography should be performed early in the event of CVL blockage. A multicenter, controlled trial assessing optimal warfarin therapy in this patient population is indicated.

Catheter-related thrombosis in critically ill children: comparison of catheters with and without heparin bonding

OBJECTIVE

To compare the incidence of and factors associated with vascular thrombosis after placement of heparin-bonded and standard femoral venous catheters.

DESIGN

Prospective, masked, clinical study.

SETTING

Multidisciplinary, tertiary, pediatric intensive care unit.

PATIENTS

Consecutive cases (n = 50) of critically ill children admitted to a pediatric intensive care unit in whom either a heparin-bonded (n = 25) or a standard (n = 25) femoral venous catheter was placed.

MEASUREMENTS AND MAIN RESULTS

Patients were examined by ultrasonography within 3 days of catheter insertion, weekly while the catheter was in place, and after catheter removal for evidence of vascular thrombosis. Data were collected prospectively regarding clinical evidence of catheter thrombosis, infusate composition, and positive blood culture results. Of 50 patients, 13 (26%) had thrombotic complications, 11 (44%) of the 25 patients in the standard-catheter group, in comparison with 2 (8%) of the 25 patients in the heparin-bonded catheter group (p = 0.004). In addition, there was a significantly higher incidence of positive blood culture results among patients in the standard-catheter group (24% vs 0%; p = 0.009). Positive catheter blood culture results were obtained in 38% of patients with thrombosis versus 3% without thrombosis (p = 0.001). Clinical evidence of thrombosis was found in 69% of patients with, versus 27% of patients without, ultrasound-proved thrombosis (p = 0.007).

CONCLUSION

Heparin bonding of catheters is associated with significantly fewer thrombotic complications. A reduced incidence of positive catheter-related blood culture results may be associated with the absence of thrombosis.

Reduction of the plasma levels of tissue plasminogen activator after infusion of a lipid emulsion in humans

A lipid emulsion of soybean oil, egg lecithin, and glycerol, widely used as a standard component of parenteral nutrition regimens, has been reported to induce changes in some hemostatic parameters known to be associated with increased thrombotic risk. We studied the effect of a single infusion of this lipid emulsion (500 mL of a 10% emulsion, give over 5 to 6 hours) on the plasma levels of tissue plasminogen activator and plasminogen activator inhibitor 1 antigens in 12 patients with various diseases. Twelve matched patients, not treated with lipid, served as controls. In patients receiving the lipid emulsion, tissue plasminogen activator was markedly reduced at the end of the infusion (p < .001) and remained significantly lower than the basal levels 24 hours later (p < .05). By contrast, in control patients, the activator was slightly but significantly increased (p < .01) at the time interval corresponding to the postinfusion sample. Plasminogen activator inhibitor 1 was similar in control and treated patients at all intervals. The release of tissue plasminogen activator in response to 10 minutes of venous stasis, evaluated in six lipid-treated patients at the end of the infusion, was not different from that observed in six control patients. It is concluded that the lipid emulsion induces a marked decrease in the circulating levels of tissue plasminogen activator.

Thrombogenicity of total parenteral nutrition solutions: II. Effect on induction of endothelial cell procoagulant activity

Thrombosis is a common sequela of total parenteral nutrition. We have recently demonstrated in vitro that hypertonic total parenteral nutrition solutions are potent inducers of a tissue factor monocyte procoagulant activity, the initiating cofactor of the extrinsic clotting cascade. We have further studied, in vitro, the effects of the component solutions of total parenteral nutrition on the induction and modulation of endothelial cell procoagulant activity. Cultured porcine aortic endothelial cells were incubated with (a) 200 microliters of dextrose solution (5%, 10%, 20%, 25%, and 50%), (b) 200 microliters of amino acid solution [full strength (N), one-fourth strength, and one-half strength], and (c) 200 microliters of 10% lipid emulsion. Cocultures of lipid emulsion and 20% dextrose, lipid emulsion and full-strength 10% amino acid solution (N-amino acid), and lipid emulsion and bacterial lipopolysaccharide also were studied. Cells were incubated for intervals of 3-108 h, washed and frozen, harvested, and assayed for endothelial cell procoagulant activity. Units of endothelial cell procoagulant activity were derived from a standard thromboplastin curve. Our results show that amino acid and hypertonic dextrose total parenteral nutrition solutions are able to strongly induce endothelial cell procoagulant activity expression in vitro. In contrast, lipid emulsion significantly inhibited the induction of endothelial cell procoagulant activity by 20% dextrose, N-amino acid, and lipopolysaccharide. These results provide further evidence for the role of the cellular pathways of coagulation in total parenteral nutrition-induced thrombosis. Furthermore, the inhibitory properties of lipid emulsion may be of practical advantage in reducing total parenteral nut induced thrombosis.