Presentation on theme: "State Secretary, ISA, TamilNadu"— Presentation transcript:
1 State Secretary, ISA, TamilNadu Anesthesia and newer anticoagulantsDr.AL.Meenakshi sundaram MD DAProf of Anesthesiology, Thanjavur Medical CollegeGC Member, ISA NationalState Secretary, ISA, TamilNadu
2 Why special?Increased awareness of DVTIncreased prophylaxisIncreased use of anticoagulantsIncreased surgical patients with anticoagulants
3 Types of Anticoagulants UNFRACTIONATED HEPARINLMWHWARFARINANTIPLATELET AGENTSTHROMBOLYTICSFIBRINOLYTICS
4 On /for Thrombolytic therapy At risk of serious hemorrhagic events, particularly those who have undergone an invasive procedure.Second Consensus Conference on Neuraxial Anesthesia and Anticoagulation (April 25-28, 2002)Queries prior to the thrombolytic therapyRecent history of lumbar punctureSpinal or epidural anesthesiaEpidural steroid injectionAllow appropriate monitoring
5 On /for Thrombolytic therapy Evaluate whether fibrinolytic or thrombolytic drugs have been used preoperativelyAny likelihood of being used intraoperatively or postoperativelySpinal or epidural anesthetic only in highly unusual circumstancesData are not available to clearly outline the length of time neuraxial puncture should be avoided after discontinuation of these drugs
6 On /for Thrombolytic therapy If neuraxial blocks at or near the time of fibrinolytic and thrombolytic therapy, neurological monitoring should be continued for an appropriate intervalInterval of monitoring should not be more than two hours between neurologic checksEpidural catheter infusion should be limited to drugs minimizing sensory and motor blockThere is no definitive recommendation for removal of neuraxial catheters in patients who unexpectedly receive fibrinolytic and thrombolytic therapy during a neuraxial catheter infusionThe measurement of fibrinogen level (one of the last clotting factors to recover) may be helpful
7 Anesthetic Management --Unfractionated Heparin Established over two decades agoSupported by in-depth reviews of case series & spinal hematomaand the ASA Closed Claims ProjectSubcutaneous (mini-dose) prophylaxis – no contraindicationThe risk of neuraxial bleeding reduced by delay of the heparin injincreased in debilitated patients after prolonged therapy.platelet count assessed prior to neuraxial block and catheter removal(More than 4 days of Heparin Therapy– HITS)
8 Combining neuraxial techniques with intraoperative heparin 1.Avoid the technique in patients with other coagulopathies2.Heparin to be delayed for 1 hour after needle placement3.Indwelling neuraxial catheters should be removed 2-4 hours after the last heparin dose and the patient's coagulation status is evaluated4.Re-heparinization should occur one hour after catheter removal
9 Combining neuraxial techniques with intraoperative heparin 5.Monitor the patient postoperatively to provide early detection of motor blockade6.use of minimal concentration of local anesthetics -- early detection of a spinal hematoma7.There are no data to support mandatory cancellation of a case in a bloody tap
10 Preoperative LMWH Can be assumed to have altered coagulation Needle placement should occur at least hours after the LMWHPatients receiving higher (treatment) doses of LMWH, such as enoxaparin 1 mg/kg every 12 hours, enoxaparin 1.5 mg/kg daily,dalteparin 120 U/kg every 12 hours, dalteparin 200 U/kg daily, or tinzaparin 175 U/kg daily will require delays of at least 24 hours to assure normal hemostasis at the time of needle insertionNeuraxial techniques should be avoided in patients with LMWH two hours preoperatively ( peak anticoagulant activity)Preoperative LMWH
11 Postoperative LMWH Twice daily dosing Increased risk of spinal hematomaThe first dose of LMWH should be administered no earlier than 24 hours postoperatively (surgical) hemostasisIndwelling catheters should be removed prior to initiation of LMWH thromboprophylaxisIf a continuous technique is selected, the epidural catheter may be left indwelling overnight and removed the following day, with the first dose of LMWH administered at least two hours after catheter removalPostoperative LMWH
12 Postoperative LMWHSingle daily dosingThis dosing regimen approximates the European applicationThe first postoperative LMWH dose should be administered 6-8 hours postoperativelyThe second postoperative dose should occur no sooner than 24 hours after the first doseIndwelling neuraxial catheters may be safely maintainedThe catheter should be removed a minimum of hours after the last dose of LMWHSubsequent LMWH dosing should occur a minimum of 2 hours after catheter removal
13 Regional Anesthetic Management of the Patient on Oral Anticoagulants Perioperative warfarin--- controversialThe anticoagulant must be stopped, (ideally 4-5 days prior to the planned procedure) and the PT/INR measured prior to initiation of neuraxial block.Early after discontinuation of warfarin therapy, the PT/INR reflect predominantly factor VII levels, and in spite of acceptable factor VII levels, factors II and X levels may not be adequate for normal hemostasis.Adequate levels of II, VII, IX, and X may not be present until the PT/INR is within normal limitsThe concurrent use of medications that affect other components of the clotting mechanisms may increase the risk of bleeding complications without influencing the PT/INR(Aspirin, NSAIDs, ticlopidine and clopidogrel, unfractionated heparin and LMWH
14 Management of the Patient on Oral Anticoagulants Warfarin prior to surgery, (first dose was given more than 24 hours earlier) the PT/INR should be checked prior to neuraxial blockLow dose warfarin therapy during epidural analgesia -- PT/INR monitored on a daily basis, and checked before catheter removal, if initial doses of warfarin are administered more than 36 hours preoperatively5 mg of warfarin –safe epidural analgesia . Higher dose warfarin may require more intensive monitoring of the coagulation statusNeuraxial catheters should be removed when the INR is <1.5. This value was derived from studies correlating hemostasis with clotting factor activity levels greater than 40%.
15 WarfarinNeurologic testing of sensory and motor function should be performed routinely during epidural analgesia for patients on warfarin therapyAn INR > 3 should prompt the physician to withhold or reduce the warfarin dose in patients with indwelling neuraxial catheters
16 Anesthetic Management of the Patient Receiving Antiplatelet Medications Antiplatelet medications, including NSAIDs, thienopyridine derivatives (ticlopidine and clopidogrel) and platelet GP IIb/IIIa antagonists (abciximab, eptifibatide, tirofiban) exert diverse effects on platelet functionThere is no wholly accepted test, including the bleeding time, which will guide antiplatelet therapyHistory of easy bruisability/excessive bleeding, female gender, and increased ageThe actual risk of spinal hematoma with ticlopidine and clopidogrel and the GP IIb/IIIa antagonists is unknownDiscontinuation of thienopyridine therapy and neuraxial blockade is 14 days for ticlopidine and 7 days for clopidogrel
17 Platelet GP IIb/IIIa inhibitors exert a profound effect on platelet aggregation Following administration, the time to normal platelet aggregation is hours for abciximab and 4-8 hours for eptifibatide and tirofibanNeuraxial techniques should be avoided until platelet function has recovered.GP IIb/IIIa antagonists are contraindicated within four weeks of surgeryCyclooxygenase-2 inhibitors have minimal effect on platelet function and should be considered in patients who require anti-inflammatory therapy in the presence of anticoagulation
18 inhibiting platelet aggregation blocking coagulation factors New Anticoagulants (Direct Thrombin Inhibitors and Fondaparinux)New antithrombotic drugs which target various steps in the hemostatic systeminhibiting platelet aggregationblocking coagulation factorsenhancing fibrinolysis are continually under development.The most extensively studied are antagonists of specific platelet receptors and direct thrombin inhibitorsMany agents have prolonged half-lives and are difficult to reverse without administration of blood components
19 Thrombin InhibitorsRecombinant hirudin derivatives, including desirudin, lepirudin, and bivalirudin inhibit both free and clot-bound thrombin.Argatroban, an L-arginine derivative, has a similar mechanism of actionDue to the lack of information available, no statement regarding risk assessment and patient management can be made
20 Fondaparinux Antithrombotic effect through factor Xa inhibition. The FDA released it with a black box warning similar to that of the LMWHsThe actual risk of spinal hematoma with fondaparinux is unknownClose monitoring of the surgical literatureUntil further clinical experience is available, performance of neuraxial techniques should occur under conditions utilized in clinical trials (single needle pass, atraumatic needle placement, avoidance of indwelling neuraxial catheters)If this is not feasible, an alternate method of prophylaxis should be considered
21 NSAID NSAIDs appear to represent no added significant risk At this time, there do not seem to be specific concerns as to the timing of single-shot or catheter techniques in relationship to the dosing of NSAIDs, postoperative monitoring, or the timing of neuraxial catheter removal.
22 WHY THE CONCERNS……. TRYBA ETAL, INCIDENCE OF OF SPINAL HEMATOMA IS LESS THAN 1 IN 1, FOR EPIDURALS; 1 IN FOR SPINAL ANESTHETICSVANDER MUELLEN ETAL,ANESTH ANALG 1994;79;REVIEW OF LITERATURE BETWEEN 1906 AND 1994 REVEALED 42 SPINAL HEMATOMAS ASSOCIATED WITH NEURAXIAL BLOCKADEAMERICAN HEART ASSOCIATION TASK FORCE ON MANAGEMENT OF PATIENTS WITH MI RECOMMENDSASPIRIN/CLOPIDOGRELUNFRACTIONATED HEPARIN/LMWHGP IIb-IIIa ANTAGONIST
23 SIXTH AMERICAN COLLEGE OF CHEST PHYSICIANS CONSENSUS CONFERENCE
24 CASE 180 YR OLD FEMALE POSTED FOR ELECTIVE TOTAL KNEE ARTHROPLASTY.PAST H/O AF, CCF AND HEMORRHAGIC GASTRITIS FOLLOWING ASPIRIN INGESTION.CURRENTLY ON CLOPIDOGREL,FRUSEMIDE, VERAPAMIL, AND LANZOPERAZOLECOAGULATION SCREEN NORMAL.DALTEPARIN SC GIVEN 10 HRS BEFORE THE ELECTIVE SURGERY TO PREVENT DVT.CONCERNS???????
25 LACK OF MONITORING DEVICE FOR ANTI X a ACTIVITY PROLONGED HALF LIFEIRREVERSIBILITY WITH PROTAMINEPROLONGED IN RENAL FAILUREREVIEW OF LITERATURE40 CASES OF SPINAL HEMATOMA REPORTED IN U.S.A AFTER 5YRS OF USE OF LMWH13 CASES OF SPINAL HEMATOMA REPORTED IN EUROPE AFTER 10 YRS OF USE OF LMWH
26 WHY THIS DIFFERENCE????IT WAS A OD DOSING IN EUROPE WITH FIRST DOSE BEING ADMINISTERED 12H PREOPERATIVELY.IN U.S IT WAS A BD DOSING REGIME WITH FIRST DOSE ADMINISTERED IN IMMEDIATE POST OPERATIVE PERIOD.FDA ISSUED WARNINGS……….FIRST CONSENSUS CONFERENCE IN 1998RADICULAR PAIN WAS NOT THE PRESENTING SYMPTOMMORE THAN HALF OF PATIENTS DEVELOPED NEURO DEFICIT 12H AFTER CATHETER REMOVALMEDIAN TIME BETWEEN LMWH THERAPY AND NEURO DYSFUNCTION WAS 3 DAYSTIME FROM ONSET OF SYMPTOMS TO LAMINECTOMY WAS >24HRSLESS THAN 1/3 PATIENTS REPORTED FAIR RECOVERY
28 CURRENT GUIDELINESTIME INTERVALS BETWEEN NEURAXIAL NEEDLE PLACEMENT AND LMWH ADMINISTRATION SHOULD BE MAINTAINED.ASK NURSING STAFF TO ADMINISTER LMWH AT A SPECIFIC TIME.OD DOSING PREFERRED TO BD REGIME.ANTI Xa MONITORING NOT MANDATORY; IT DOES NOT PREDICT THE RISK OF BLEEDING.PRESENCE OF BLOOD DURING NEEDLE AND CATHETER PLACEMENT DOES NOT NECISSATE POSTPONEMENT.BUT INITIATION OF LMWH SHOULD BE DELAYED FOR 24 HRS POSTOPERATIVE.
29 10 HRS LATER THE PATIENT WAS GIVEN A CSE. EPIDURAL CATHETER CONTINUED FOR POSTOPERATIVE ANALGESIAPATIENT C/O PAIN OVER THE OPERATIVE SITE AND HER BACK FOLLOWING WHICH THE INFUSION RATE WAS INCREASED.THROMBOPROPHYLAXIS RESUMED- OD REGIMEPHYSIOTHERAPIST NOTED NUMBNESS IN THE NON OPERATED LEG THE NEXT DAY WHICH SHE ATTRIBUTED TO THE EPIDURAL.3RD POD THE EPIDURAL CATHETER WAS REMOVED, 12 HRS AFTER DALTEPARIN5 HRS AFTER REMOVAL, THE NUMBNESS WAS PRESENT WITH MILD MOTOR WEAKNESS, ATTRIBUTED TO RESIDUAL EPIDURAL BLOCK.NEURO OPINION SOUGHT 48 HRS LATER AND A MRI OF SPINE WAS DONE.
31 CASE 255 yr old gentleman, h/o unstable angina, currently admitted to the coronary care unit. he is started on aspirin, atenelol,ntg and heparin iv. bypass grafting is planned and patient is interested in postoperative epidural pain reliefConcerns??????Preoperative heparinIntraoperative heparinPostoperative heparin
32 PREOPERATIVE HEPARIN SC low dose heparin 5000 u sc q 12 h for prevention of DVTNo detectable changes in a pTT9 published series over 9000 patients have had no complicationsThree surveys of opinions of anesthesiologists in UK, Denmark and Newzealand appear to feel that SC heparin should not be a contraindication for neuraxial blockadeHeparin to be delayed till 2 hrs after blockadeHeparin > 4 days platelet count to be assessed prior to neuraxial block or catheter removal
33 PREOPERATIVE IV HEPARIN Ideally neuraxial block 1-2 hrs before iv heparin.In the presence of traumatic attempt- incidence of spinal hematoma is 50 %.Cancellation of the surgery?????Risk of spinal hematomaHo etal, chest;2000,117,Complex mathematical analysis for the probability of spinal hematoma– 1:1528 for epidural;1:3610 for spinalThe authors hypothesised that this is an acceptable risk compared mortality of post op myocardial infarction
34 INTRAOPERATIVE AND POSTOPERATIVE HEPARIN HEPARIN TO BE AVOIDED FOR 1 HR AFTER NEEDLE PLACEMENTCATHETERS REMOVED 2-4 HRS AFTER LAST HEPARIN; PATIENTS COAGULATION STATUS EVALUATED,RE HEPARINISATION STARTED 1 HR LATERMONITOR PATIENT POSTOPERATIVELY FOR MOTOR BLOCKBLOODY TAP- DISCUSS WITH SURGEON THE RISK BENEFIT ANALYSIS.
35 CASE 360 yr old lady with parkinsonism, dementia and AF, posted for THR. She is currently on warfarin, anti parkinsonian drugs. INR was 2.1. Given vit K injection. INR dropped to 1.7.Concerns????Warfarin inhibits vit K dependent factors.But the effects of warfarin not apparent until a significant amount of biologically inactive factors are present.Dependent on factor half life…….
36 WHAT IT MEANS……………..40% activity of Factor II, VII, IX, X is adequate for normal hemostasisINR AND PTT are most sensitive to changes in FAC X AND VII , its relative insensitive to FAC II activity.INR = 1.2 When FAC VII ACTIVITY IS 55%; INR =1.5 When FAC VII ACTIVITY IS 40%.Other problems with warfarinNarrow therapeutic rangeEnhanced response in old age, females, pre existing medical conditions[low wt, renal, cardiac, liver disease]
37 GUIDELINES On discontinuation of warfarin, Factor VII activity will rapidly rise, so inr will decrease.Factor II AND X activities recover much more slowly; so hemostasis may not be adequate till thenIn emergency- inject VIT K, USE FFPWarfarin ideally stopped 4-5 days priorPTT/INR Done Prior To BlockFor those where warfarin is started for DVT,[low dose 5 mg]DO INR / PT IF a] DOSE GIVEN 24 HRS PRIORB] MORE THAN 1 DOSE GIVENC] EPIDURAL CATHETER IN SITU
38 CONTD….. REMOVE CATHETER ONCE INR <1.5 NEURO TESING FOR SENSORY AND MOTOR FUNCTION AFTER REMOVAL OF CATHETER.INR>3 , WITHHOLD WARFARIN IF THERE IS AN INDWELLING CATHETER.
39 CASE 458 YR OLD MAN WITH H/O MULTIPLE TIAs, HYPERTENSION, POSTED FOR LAPAROTOMY. HE IS ON ATENELOL, ASPIRIN AND CLOPIDOGRELCONCERNS??????
40 ANTIPLATELET MEDICATIONS Aspirin in low doses [ mg/day] inhibits platelet COXIn higher doses 1.5 to2 g/day inhibits prostacyclin production[platelet aggregation inhibitor]Other NSAIDs- (Naproxen, Piroxicam, Ibuprofen) have antiplatelet activity , which normalises in 3 days.Thienopyridine derivatives- clopidogrel and ticlopidine which inhibit ADP induced platelet aggregation.Platelet GPIIB-IIIA receptor antagonists- Abciximab, Eptifibatide,tirofiban.
41 HOW TO MANAGE……..No wholly accepted test which will guide antiplatelet therapy. Thromboelastogram has been proposed to monitor clopidogrel therapyNSAIDS add no significant risk for spinal hematoma. So use of NSAIDs alone is not a risk for contraindication for neuraxial block.For thienopyridinesStop clopidogrel 7 days prior; ticlopidine 14 days priorGPIIB-IIIA RECEPTOR BLOCKERSTime for normal platelet aggregation after a single dose- 24 –48 hrs after abciximab; 4-8 hrs after eptifibatide and tirofiban
42 PLEXUS AND PERIPHERAL BLOCKS All cases of major bleeding after non neuraxial techniques occurred after psoas compartment or lumbar sympathetic blockCase reports in literature with heparin, LMWH, thienopyridine derivativesMost have them had huge retroperitoneal hematomas , with blood loss as great as 3 litreSo significant blood loss rather than neural deficits are the major complications with drop in Hb, and hypotension.Treated with blood transfusion and conservative mangaement
43 I THOT A THOT, BUT THE THOT I THOT WAS NEVER THE THOT I EVER THOT I THOT A THOT, BUT THE THOT I THOT WAS NEVER THE THOT I EVER THOT. SO I NEVER THOT THE THOT I THOT!!!!!
45 SummaryConsensus statements represent the collective experience of recognized experts in the field of neuraxial anesthesia and anticoagulationThey are based on case reports, clinical series, pharmacology, hematology, and risk factors for surgical bleedingAn understanding of the complexity of this issue is essential to patient management; a "cookbook" approach is not appropriate.Timing of catheter removal in a patient receiving antithrombotic therapy should be made on an individual basisWeighing the small, though definite risk of spinal hematoma with the benefits of regional anesthesia for a specific patient
46 Coagulation status should be optimized at the time of spinal or epidural needle/catheter placement, and the level of anticoagulation must be carefully monitored during the period of epidural catheterizationIndwelling catheters should not be removed in the presence of therapeutic anticoagulation, as this appears to significantly increase the risk of spinal hematoma.Identification of risk factors and establishment of guidelines will not completely eliminate the complication of spinal hematoma.Vigilance in monitoring is critical
47 There are two ways of meeting the difficulties You alter the difficultiesYou alter yourself to meet the difficulty