Pathology Service User Guide Haematology

Transcription

1 Pathology Service User Guide Haematology St Richard s This section of the Pathology Service User Guide includes: Anticoagulant Therapy Information about the Anticoagulant Clinic Low Molecular Weight Heparin Management of Bleeding whilst on Anticoagulants Surgery and Anticoagulants Referrals from GP Practice Cytogenetics

2 Anticoagulant Therapy For inpatients it is essential that any doctor who prescribes anticoagulant therapy is familiar with the local arrangements before commencing anticoagulants. There is a protocol integrated into the pink anticoagulation referral form. (See below)

3 PINK ANTICOAGULANT CHART AND REFERRAL FORM Surname First name This form must be completed by the doctor; and sent to Pathology Reception BEFORE the patient is discharged; or it will be returned to the ward and no appointment made. DOB Address GP Phone no: Consultant: Ward: Date discharged: Diagnosis this admission: Indication for warfarin: Target range: On warfarin on admission: Y/N Intended duration: If unknown; date of review: Other clinical details; including other diagnoses; bleeding risk; cognitive impairment; sensory impairment; past history of thrombosis: Current medication: We will discontinue aspirin/clopidogrel unless otherwise advised. State if to be continued. Discharged on: / / INR taking mg warfarin. LMWH ((Innohep): discharged on units; number of days supplied: Signed Dr: Print name: Bleep no: Counselled by CNS/pharmacist: (Signature) (Signature of patient)

4 Information about the Anticoagulant Clinic Clinics are held on Monday and Friday mornings. Patients are seen by appointment only. (Patients previously on the postal system will not usually need to attend the Anticoagulant Clinic; but must be told when to have their next INR). Please send completed form to Pathology Reception: appointments can then be arranged by phoning Ext Patients who are under 60 years of age will be supplied with 1; 3 and 5mg warfarin tablets on discharge (28 of each). Those over 60 years will be supplied with 0.5; 1 and 3mg tablets. All new patients commenced on warfarin whilst an inpatient; will be counselled by pharmacy before dischrge ( out of hours the doctor will need to counsel the patient). Warfarin is best taken in the evening. A yellow booklet will also be provided to the patient if taking warfarin for the first time. Make sure full details are entered in the yellow book; including warfarin dose. Thrombophilia screening should not be performed during an acute episode; as results can be misleading. Thrombophilia screens in patients with VTE aged <45 are therefore routinely organised by the Haematologists once warfarin has finished. Please discuss any other cases with Dr Janes.

5 Low Molecular Weight Heparin Using subcutaneous tinzaparin sodium (20;000 anti-xa U/ml); 175U/Kg once a day. This is the preferred treatment for a DVT or PE (suspected or proven). Please discuss pregnant patients with Haematologist, as LMWHs are not licensed for use in pregnancy. The Dose must be prescribed in units Body weight Units (175U/Kg) Injection volume Syringe colour Dose based on body weight D/W Haematologist if wt >120Kg Monitoring not required Treatment must continue for minimum 5 days; and until INR in range for 2 days. There should be not less than 18h; nor more than 27h; between doses. NB. LMWH accumulates in severe liver and renal failure: discuss with Haematologist re alternatives/ dose reduction/ monitoring ml Blue Blue Blue Blue Yellow Yellow Yellow Yellow Yellow Red Red Red Red Red

6 Drug interactions It should be assumed that all drugs; dietary changes; etc; can interact with warfarin; and the INR should be checked within a week of starting or stopping a drug. Particularly important interactions include: Amiodarone: if loading; check INR twice in 1st week The following drugs potentiate warfarin: Azapropazone Clarithromycin Fluconazole Simvastatin Ciprofloxacin Tamoxifen The following drugs antagonise warfarin: Rifampicin Carbamazepine Try to avoid aspirin and NSAID s with platelet antagonist effects; as these significantly increase the risk of bleeding

7 Management of Bleeding whilst on Anticoagulants Please seek advice from the Consultant haematologists Heparin: IV: As the half-life of iv heparin short; it is usually sufficient to stop infusion. Occasionally iv protamine may be required: discuss with Haematologist. LMWH: Reversal with protamine is poor. Discuss with Haematologist. Warfarin 1. Life threatening haemorrhage: 5mg Vitamin K by slow iv injection PCC (clotting factor concentrate) may be available: contact Haematologist urgently; or use: FFP 10-15mL/Kg (approx 1 litre in an adult) 2. Less severe haemorrhage, at any INR, or INR >8: Withhold warfarin for 1 or more days and review. If INR high; give Vitamin K 1-2 mg orally or iv INR>14; give Vitamin K and admit for observation 3. INR without haemorrhage: Withhold warfarin for 1-2 days and review. If unexpected bleeding occurs at therapeutic INR levels; investigate underlying cause. Oral Vitamin K well absorbed and works rapidly: iv route can cause anaphylaxis.

8 WARFARIN Guidelines for ranges and duration of warfarin therapy Indication Target INR Duration Atrial fibrillation/mitral valve disease/ 2-3 Indefinite Cardiomyopathy/mural thrombus AF for cardioversion month before and after; then 2-3 Proximal DVT/PE months Below knee DVT/provoked event months Mitral valve replacement 3-4 Indefinite Aortic valve replacement Indefinite Tissue (porcine) valve months if requested Arterial grafts (if indicated) 3-4 As indicated Others (specify).... Start Warfarin Day 1, unless massive PE, when consider delaying Warfarin for hrs. IV heparin is prescribed on a separate pink chart, which is available to download from the main haematology webpage.

9 Warfarin loading : D1-4 the INR should be checked daily. Tick regimen used: USE ONE ONLY Full dose loading Age <75, and no amiodarone; or previous Warfarin dose >3mg Reduced dose loading Age >75, or amiodarone or previous Warfarin dose 3mg INR Warfarin dose (mg) INR Warfarin dose (mg) Day 1 < Day 1 <1.4 5 Day 2 < Day 2 < ³1.8 0 ³1.8 0 Day 3 < Day 3 < >3.5 0 >3.5 0 Day 4 < Day 4 < miss 1 day then 2mg miss 1 day then 1mg >4.5 miss 2 days then 1mg >4.5 miss 2 days then 1mg To calculate maintenance dose, continue day 4 dose for 3 more days. Repeat INR day Warfarinization where loading not required. eg longstanding AF. Start warfarin 3mg daily, and book patient into Anticoagulant Clinic for an INR after exactly seven days of warfarin. Not applicable if concurrent loading with amiodarone: seek advice from Anticoagulant nurses.

10 Surgery and Anticoagulants For routine surgery we offer a peri-operative service. Patients are referred via the pre-op assessment clinic by letter. We will plan their treatment; give instructions to the patient and a copy of the schedule is clipped to the patient s notes. For acute admissions requiring surgery refer to the Guidelines For The Management Of Common Medical Emergencies And For The Use Of Antimicrobial Drugs The Grey Book or discuss with Consultant Haematologist.

11 Referrals from GP Practice Please complete an anticoagulation referral form. Some GP practices have an electronic version of the form that can then be be printed off. It can also be downloaded from the main haematology webpage. This needs to be faxed; and a hard copy sent to the anticoagulation clinic (these forms can be obtained from the clinic.) We also offer a patient education session for new patients commencing on warfarin.

12 Cytogenetics All samples for cytogenetic analysis and molecular studies are sent away via the Department of Haematology; which holds and monitors the budget for such samples and arranges transport. Samples must not be sent directly to other institutions. Peripheral blood; bone marrow; amniotic fluid and solid tissue samples are handled in this way. Although suitably labelled samples may be sent to the haematology laboratory without prior arrangement; it is advisable to notify the laboratory on extensions 3582 / 3585 that a sample is about to be sent. This is particularly important on Fridays and weekends. At present; service level agreements are held with King s College Hospital for haematological malignancies and St. George s Hospital for all other samples. As this is a rapidly evolving field; we need to be made aware of any proposals to introduce any new test. Blood and bone marrow samples must be collected into tubes containing culture medium containing preservative-free heparin or orange-topped lithium heparin tubes; both of which are available from Haematology. Note: the normal vacutainer specimen bottles are unsuitable for the collection of blood samples; as they contain inhibitory substances. Solid tissue samples; for investigation of unexplained foetal death; must be placed in the tissue culture medium available from haematology. As a skin sample is the tissue of choice; please send to the laboratory as soon as possible to avoid deterioration. Please ring Haematology prior to sending samples.