Filename: Paediatric Thrombosis and Anticoagulation Guideline
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- Bu səhifədəki naviqasiya:
- Indications for use of aspirin in children (plus see tables below)
- Tissue-type plasminogen activator (rt-PA)
Paediatric Thrombosis and Anticoagulation Guidelines Contents Introduction 2 Section A – Management of Thrombosis The Neonate/PICU 3 Venous Thrombosis 3 Arterial Thrombosis 4 Paediatric Cardiology 5 Indications for Use of Aspirin 5 Devices and Stents 6 Valve replacement 6 Cavopulmonary shunt/Fontan 7 Other indications 7
Central Venous Sinus Thrombosis 8 Lower limb DVT 8 PE 9
Upper Limb DVT and Hickman/Portacath associated thrombi 9 Extrinsic compression due to tumour 9 Thromboprophylaxis 10
Unfractionated Heparin 12 Protamine rescue 13 Warfarin 13 Tissue-type plasminogen activator (rt-PA) 14
Enoxaparin – Preparation Guidelines 16 Procedure for the home administration of subcutaneous Clexane/LMWH by parent/carer 17 Teaching Checklist for home administration of subcutaneous medication by patient or carer 19 Appendix B Cardiff and Vale UHB: Paediatric Warfarin Care Pathway 20 Paediatric Inpatient Warfarin Treatment Chart 22 Appendix C Cardiff and Vale surgical thromboprophylaxis risk assessment
B) Safe Use of Medicines The anticoagulants themselves are potentially dangerous agents and require careful prescribing within a Quality Managed System. This document is part of that system. All anticoagulants commonly used in children require dose monitoring Generally LMWH is preferred. Check renal function, FBC and clotting screen before use. Use UFH if there are concerns about possible bleeding. Check renal function, FBC and clotting screen before use Use Warfarin/asparin for specific cardiology indications
9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012; 141(2)(Suppl):e737S–e801S A) Management of Thrombosis The Neonate/PICU Neonatal thrombosis is rare and occurs in 2.4/1000 admissions to the neonatal unit. The evidence base for the management of neonatal thrombosis is minimal and is largely based on case series and extrapolated data from adult literature. Thrombotic events on PICU are frequently associated with intravascular catheters and can be managed in a similar way Predisposing factors: Include indwelling intravascular catheters, congenital heart disease, polycythaemia, poor deformability of neonatal red cells, shock, sepsis and dehydration. Congenital prothrombotic disorders account for 5-20% of all thrombotic episodes and they should be considered in any neonate with a clinically significant thrombosis, spontaneous thrombotic events, unanticipated or extensive venous thrombosis, ischaemic skin lesions, purpura fulminans or family history of purpura fulminans. Venous Thrombosis Venous thrombi constitute about 65-75% of all neonatal thrombotic events. Over 80% are central line related. Umbilical venous catheters must be correctly placed (in the IVC- not in the portal veins) and used for as short a period as possible. Clinical presentation will depend on thrombus location, but in general occurs with loss of catheter patency, swollen, painful and discoloured limb. Superior vena caval obstruction presents with swelling of the face and neck and chylothoraces. Pulmonary thromboembolism presents with respiratory compromise. Renal vein thrombosis presents as a palpable flank mass, haematuria, proteinuria, renal impairment and thrombocytopenia. Oedematous, cold, discoloured lower limbs may indicate extension of the thrombus into the IVC. Portal vein thrombosis is often difficult to identify by clinical means. An USS of the portal system may be considered if there is unexplained thrombocytopenia in a sick neonate. Management: Remove the indwelling catheter. Precious lines can be salvaged by anticoagulation but this is beyond the scope of this guideline and must be discussed with Paediatric/Coag Haematology
Arterial Thrombosis Arterial thromboses account for 25-35% of all neonatal thromboses and are almost exclusively secondary to indwelling arterial catheters. UA catheters should always be appropriately placed at T6-T10 or between L3-L5. Careful monitoring of colour, temperature, capillary refill time and pulses are important for early detection. Management
Contraindications for thrombolysis:
Stuck long lines: Reported between 1 and 12% in older children and adults, no neonatal data available. Venospasm is the main cause for difficulty in removal although other causes include infection, fibrin formation and endothelial thrombosis. It usually occurs in medium sized veins especially basilic and cephalic veins Management:
Congenital Prothrombotic disorders: Complete absence of Protein C or S warrants life long anticoagulation but testing for the other disorders does not alter management and current UK guidance is not to test Ref Clinical guidelines for testing for heritable thrombophilia, British Journal of Haematology 2010, (149), pp 209–220 Paediatric Cardiology Indications for use of aspirin in children (plus see tables below):
If aspirin cannot be used (e.g. allergy), consider the use of other agents such as dypridamole or clopidogrel (limited data in children). In the event of development of chicken pox, herpes, influenza, rubella, or other severe flu-like febrile illness, the clinician will determine whether the risks / benefits of continuing aspirin vs the small risk of Reye’s syndrome. Parents should be instructed to telephone to ask for advice in this situation. Patients on aspirin should not have Fluenz nasal immunisation – instead they should have the injected flu vaccine. Also consider varicella vaccination. Patients on aspirin for a B-T shunt should not have therapy discontinued, even during a febrile illness; however patients with a weaker indication for aspirin (e.g. chronic cyanosis with a cavopulmonary shunt, Kawasaki disease) should discontinue aspirin temporarily during the feverish phase of an illness. The consultant may consider use of dypridamole or clopidogrel during this period (NB the data sheet for clopidogrel also advises discontinuation during chicken pox, etc). Devices and Stents
*NB – there may be individual clinical reasons to extend treatment, to supplement with other antiplatelet agents (e.g. clopidogrel), or to use formal anticoagulation. Aspirin dose of 150 mg or 300 mg may be used in older adolescents. See section 6.1.1 for advice regarding use of aspirin during intercurrent illness. Valve replacement
*NB – there may be individual clinical reasons to extend treatment, to supplement with other antiplatelet agents (e.g. clopidogrel), or to use formal anticoagulation. Aspirin dose of 150 mg or 300 mg may be used in older adolescents. See section 6.1.1 for advice regarding use of aspirin during intercurrent illness. **NB – there may be individual clinical reasons to use a higher range, e.g. small valve, or increased risk of thrombosis – this needs to be clearly specified in the medical notes and in the INR booklet. Our unit experience tells us that an upper range of 4 has been used without adverse incidents in the past. AHA guidelines recommend a target INR of 2.5 (range 2.0 – 3.0) for aortic valve replacement with a Starr-Edwards valve or a tilting disk valve (other than Medtronic-Hall) with no other risk factors (reference Circulation 2013;128:2622-2703). Based on our local experience, this unit will continue to have a target INR of 2.5 in all prosthetic paediatric aortic valve replacements.
*NB – See section 6.1.1 for advice regarding use of aspirin during intercurrent illness. **NB – There may be individual clinical reasons to extend treatment, to supplement with other antiplatelet agents (e.g. clopidogrel), or to use formal anticoagulation. ***NB – Some patients may be treated with aspirin rather than warfarin – the reasons for this should be clearly stated in the surgical summary and the local patient record. AHA guidelines support the use of aspirin alone in uncomplicated Fontan patients, and Warfarin in patients with adverse risk factors (see reference above).
*NB – there may be individual clinical reasons to extend treatment, to supplement with other antiplatelet agents (e.g. clopidogrel), or to use formal anticoagulation. Aspirin dose of 150 mg or 300 mg may be used in older adolescents. See section 6.1.1 for advice regarding use of aspirin during intercurrent illness. References:
The Cancer Patient/General Paediatrics This covers medical and surgical in-patients over the age of 1 and under 18 who are not critically unwell on an intensive care unit and have normal cardiac anatomy. The common scenarios are
In cancer patients all of the above can be exacerbated and/or precipitated by asparaginase For all of the above LMWH is the anticoagulant of choice. Check renal function, FBC and clotting screen before use See Section B for dosing Children can be discussed with Paediatric/Clotting Haematology 1) Central Venous Sinus Thormbosis Discuss with Paediatric Neurology Predisposing Factors Iron deficiency, microcytic anaemia, dehydration, local (usually middle ear area) infection, asparaginase Present with lethargy, anorexia headache, vomiting, seizures, focal signs or coma. MRI investigation of choice due to lack of radiation but CT angiogram has fewer artefacts and is easier to arrange as an emergency Treat for 3 months if there is a clear precipitating cause and 6 months if no cause identified. Small intracranial haemorrhages are not contraindications to anticoagulation. In a massive bleed resulting in local mass effect or intraventricular haemorrhage it is reasonable to withhold anticoagulation 2) Lower limb DVT Rare in children. Discuss with Paediatric/Clotting Haematology Separate into “above” and “below knee” based on Doppler report and “idiopathic/spontaneous” or “secondary/precipitated” based on history Predisposing factors Obesity, immobility, malignancy, smoking, age (amongst others), asparaginase Present with lower limb swelling, pain and erythema. Doppler angiogram of lower limbs the investigation of choice. Do not test D-Dimers Treatment of below knee: either re-scan in 7 days or treat for up to 3 months (min 6 weeks) anticoagulation Treatment of above knee Prciptated – 3 months of anticoagulation Idiopathic – 6 months of anticoagulation 3) PE Rare in children. Discuss with Paediatric/Clotting Haematology Predisposing factors Obesity, immobility, malignancy, smoking, age (amongst others), asparaginase Present with chest pain, shortness of breath, hypoxia. CTPA is the initial investigation of choice. Do not test D-Dimers Treat with 6 months of anticoagulation. 4) Upper limb DVT and Hickman/Portacath associated thrombi Common in cancer patients (2.7% of ALL patients in Cardiff). Discuss with Paediatric/Clotting Haematology Predisposing factors Central line, dehydration, cancer, asparaginase. US is the investigation of choice. MRI/MRV may be required for central veins Treat by removing the line and anticoagulate for 3 months. “Precious” lines may remain in-situ but will management must be discussed with Paediatric/Clotting Haematology 5) Extrinsic compression due to tumour Common in cancer patients. Discuss with Paediatric/Clotting Haematology Predisposing factors Central line, dehydration, cancer, asparaginase US is the investigation of choice to demonstrate occlusion. Tumour will be imaged as part of staging. Responding tumours with thrombus present at diagnosis may only need 3 months of anticoagulation beyond signs of the tumour shrinking. Relapsed/refractory tumours may need long term anticoagulation 6) Thromboprophylaxis NICE Clinical Guideance 92 does not apply to people under the age of 18 General preventative measures in all children (both medical and surgical cases) are adequate hydration, early mobilisation post-operatively and removal of central lines as soon as they are no longer required. Physical methods of prevention such as compression stockings should be considered in older children Pharmacological methods of prevention have no evidence base at the moment. In general we would not recommend using thromboprophylaxis in unselected cases (ie no blanket use in all children). All surgical patients (from neonates to geriatrics) at UHW are subject to preoperative thromboprophylaxis risk assessment, a copy of which is in Appendix C. Remember that this is a guideline and there may be specific circumstances in which thromboprphylaxis may be necessary but we have not foreseen . There is no validated scoring system to assess risk for children. A scoring system has been developed for PICU and pre-operative patients. Retrospective analysis/audit of VTE in children at UHW has suggested the current guideline. We will audit this in the future In post-pubertal girls on the contraceptive pill undergoing surgery consideration should be given to stopping 4 weeks prior to surgery. Beware, unwanted pregnancy could be a consequence, please advise use of alterative contraception and document this. See Cardiology paragraphs in Section A for specific cardiac conditions such as mechanical valves. Ref: Guideline on the investigation, management and prevention of venous thrombosis in children British Journal of Haematology, 2011 (154), pp196–207
LMWH (enoxaparin): Neonate 1.5 – 2 mg/kg 1 - 2mo age: 1.5mg/kg >2mo age: 1.0 mg/kg. During therapy: Phone laboratory to discuss timing of anti-Xa levels. Samples can be frozen and defrosted for a routine run. Prior to the assay the instrument (automated coagulation machine) must be purged/cleaned. This takes several hours and may mean the rest of the hospital will not be able to get coagulation results. Be careful what you call “urgent” results Target anti-Xa is 0.5-1iu/ml Administer 4 to 5 doses (2 to 3 days worth) before checking levels. Do NOT use insuflons or other S/C devices to administer doses – they cause marked variation in total drug dose delivered Measure anti Xa 4 hours after dose and adjust according to table: Anti Xa Hold next dose Dose change Repeat Xa level? <0.35U/ml no Increase by 25% 4h after 4 doses 0.35-0.49U/ml no Increase by 10% 4h after 4 doses 0.5-1.0U/ml no no 1 week later, then monthly while receiving enoxaparin (4h after am dose) 1.1-1.5U/ml no Decrease by 20% Before next dose 1.6-2.0U/ml 3h Decrease by 30% Before next dose, then 4h after next >2.0U/ml Until Xa ≤ 0.5 Hold Before next dose, If not≤ 0.5, repeat then decrease by 40% q12h
thrombosis heparin has been used for 3 – 6 months. The child’s carer will be competency assessed prior to discharge to ensure safe home administration of LMWH. Written instructions will be given to the carer on how to administer (see Appendix A for documents) Unfractionated Heparin (UFH) Prior to therapy:
During Therapy APTTR = patient’s APTT / mid point of normal range For example, if the APTT is 32 seconds and the range is 26 to 38 seconds: APTTR = 32/[(38-26)/2] + 26 = 32/(6 + 26) = 32/32 = 1 Maintain APTT between 60 and 85 seconds. This corresponds to an APTTR 1.5 to 2.5. Give by IV route Loading dose: 75 U/kg over 10 minutes } Check with BNFc Maintenance: 10 – 20 U/kg/hr (higher doses may be needed) } Check APTT 6 – 8 hours after starting therapy. If APTT ratio is LOW – increase maintenance dose by 10-20% and recheck APTT ratio 4-6 hours later. If APTT ratio is >2 and ≤3, reduce the maintenance dose by 10% and recheck APTT ratio 6-8 hours later. If APTT ratio is >3, stop heparin for 1 hour, then restart at a reduced maintenance dose (reduce by 20%). NB – if maintenance doses of >35 U/kg/hour are required it may be appropriate to accept slightly lower APTT ratios.
Administer protamine sulphate as follows (based on total amount of heparin received in last 2 hours):
Warfarin Procedure and process of prescription and parent competency assessment shall be done as per the All Wales Paediatric Warfarin Care Pathway and prescribed on the all Wales Paediatric In-Patient Warfarin Treatment Chart. Copies of these documents are given in Appendix B Tissue-type plasminogen activator (rt-PA)Most often used in neonates to treat life or limb threatening thrombosis. Treatment of neonatal thrombosis is still controversial. The evidence based for the management of neonatal thrombosis is very limited and is mostly based on case series and extrapolated adult literature. Tissue type plasminogen activator (t-PA) has been used to treat both neonatal arterial and venous thrombosis. Consider t-PA for the following Indications:
Absolute contraindications for use:
Relative contraindications for use:
Prior to initiating therapy
Dose Regimens - there is no Trial data to support one over the other. Case series evidence favours the low dose regimen as less likely to cause severe bleeds High Dose: Give a loading dose of 0.1mg/kg, followed by an infusion of 0.3-0.5mg/kg/hr over 6 hours. Low dose: Give 0.1mg/kg/hr for 4 hours. Once the infusion is complete, start UFH (protocol as above) and continue until next rt-PA infusion. Perform ultrasound scan of thrombosed vessel at the end of infusion and if recanalisation is not complete. Up to four additional doses of t-PA can be given at intervals of 12-24 hours. During therapy:
Ref Ref: Guideline on the investigation, management and prevention of venous thrombosis in children. British Journal of Haematology, 2011 (154), pp196–20 
Appendix A Enoxaparin – Preparation Guidelines
Child Health Directorate Procedure for the home administration of subcutaneous Clexane by parent /carer using multi-dose vial or pre-filled syringe Clexane dose ………………… Preparation used (mg/ml) …………………. Amount to be given (ml) …………………… Storage requirements ………………………………………………………………………… Equipment
Babies < 1month Pharmacy prepared 20mg/ml pre-filled syringes All other Babies & Children Multi-dose vial with pharmacy label containing your child’s details and:
Preparing the injection
Check that your child’s name and Clexane dose are correctly printed on the pharmacy label.
For multi-dose vial with pharmacy label containing your child’s details: Go to 4 For Pharmacy prepared 20mg/ml syringes: Go to 12
Allow surface to dry for 30 seconds.
Pull syringe plunger downward until ………… ml Clexane is drawn into syringe.
Do not touch metal shaft of needle.
Have assistant and cold spray, gauze square or tissue in place before proceeding. Giving the injection
Avoid bruised or damaged skin.
Allow the skin to dry completely so that anti-bacterial solution is not injected (very stingy).
The cold spray dries immediately on contact with the skin and will not contaminate cleaned area.
The Clexane is likely to leak from injection site if shot in very quickly.
Hold for 30 seconds to prevent Clexane leaking out. Do not rub as this may irritate the skin. Clearing up
References Royal College of Nursing (2001) Compiling a teaching package for parents, carers and older children in: Administering therapies to children in the community setting: Guidance for nursing staff. Royal College of Nursing (2010) Paediatric guidance on home administration in :Administering subcutaneous medication: RCN guidance for nurses.
Appendix A Child Health Directorate Teaching check-list for the home administration of subcutaneous medication by parent or carer
Statement by parent or carer I have received teaching and information on how to give my child’s medication by subcutaneous injection. I now feel able to give the injection safely at home. I know who to contact if any problems arise.
SURGICAL THROMBOPROPHYLAXIS RISK ASSESSMENT IS THE SURGICAL PATIENT POST-PUBERTAL or AGE > 13 YEARS? Yes No 
Yes Is the procedure under local or regional anaesthesia with no reduction in mobility? Yes Thromboprophylaxis is not required and the Risk Assessment is complete (sign below) Unless contraindicated surgical patients should receive pharmacological and mechanical thromboprophylaxis Note: although risk of VTE increases during adolescence, absolute risk remains low compared to adults. There is little evidence to support the use of specific modalities of thromboprophylaxis in non-adult surgical patients (clinical decision by surgeon on a case by case basis is advised)    
No No        
Reassess every 24– 48 hours     
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