Routine clotting studies a bloody waste of resources?

Joanne Bratchell Lead Nurse Pre-operative Assessment St George’s Hospital, Tooting Antonia Field-Smith Specialist Registrar in Haematology

Defensive?

Persuasion?

The problem with clotting screens

    Do not predict bleeding risk in most patients Do not accurately reflect in vivo haemostatic response Designed to detect factor deficiencies in patients with high pre-test probability of bleeding Low sensitivity and specificity

The clotting cascade

Causes of abnormal clotting screens

 Prolonged clotting times  flawed collection or prolonged storage      anticoagulants heparin contamination

coagulation factor deficiency

 inherited  acquired lupus anticoagulant factor inhibitor  Shortened clotting times  slow or difficult venepuncture     incorrect volume of blood in tube inadequate mixing usually not clinically significant ?increased thrombotic risk

Background

  Lack of clear NICE guidelines meant clotting screens routinely ordered pre operatively in our Trust All evidence available concludes that routine testing in apparently healthy or asymptomatic individuals is unlikely to lead to little if any benefit (Munro et al 1997, ASA 2002, NICE 2003, British Committee Standards in Haematology 2008 )

Aims and Objectives

  To determine whether preoperative clotting screens were requested in adherence with Trust guidelines To determine whether abnormal clotting results affect the clinical management or surgical outcome of elective surgical patients

Methodology

   Data collected over 2 week period Included all elective surgery patients over 18 years of age from 4 care groups attending pre-op clinic Staff asked to record whether clotting screen requested and why indicated

Results

    120/181 (66.2%) patients had clotting screens requested Only 16 (13.3%) studies requested in line with guidelines 78 (65%) ordered routinely 23/120 (19%) prolonged abnormal clotting screens

Abnormal results

Causes of abnormal clotting screens in 34 patients out of 120 with clotting screens requested

11 1 2 1 4 8 7 Warfarin Borderline raised APTR APTR >1.3

Factor XI deficiency Borderline raised INR Borderline raised TT Shortened APTR

Outcome

   No change to clinical management in patients with abnormal clotting results Only 5 out of 14 patients with unexplained prolonged clotting times had repeat testing Perioperative bleeding in 5 patients with prolonged clotting screens  All major orthopaedic cases – likely surgical bleeding

The best way forward?

Bleeding history

Family history Prolonged bleeding post op

Questions Do you have any family history of bleeding disorders, especially parents and siblings? No Yes Details Have you ever had any unexplained prolonged bleeding after surgery, dental extractions or childbirth and/or subsequently required a blood transfusion?

Nosebleeds

Do you have frequent (at least once a month) gushing nosebleeds that do not respond to pressure after 15 mins and/or require a visit to A&E?

Revised guidelines

Clotting screen

All abnormal results should be repeated Discuss any persistently abnormal results with Haematology registrar Positive bleeding history • Family history of bleeding disorder • Prolonged post-op bleeding • Nosebleeds Liver disease Renal disease Known bleeding disorder On anticoagulants Jehovah’s witnesses Refer to haematology eGFR < 30 or on dialysis Liaise with Haemophilia team Not at pre-op visit

Recommendations for practice

     Stop ordering routine clotting studies!

If positive bleeding history, refer to haematology All abnormal results should be repeated Refer to haematologist if result remains abnormal Stop ordering clotting test for warfarin pts at pre-op visit

Financial implications

   Clotting studies at St George’s cost £3.51 a time representing £ thousands per year In average year, approx £10,500 on pre-op clotting tests Potential saving of £9000 by adhering to guidelines

Conclusion

   Routine clotting studies have no value in the management of elective surgery patients Limited value to patients and significant cost implications to the Trust Clotting studies should only be ordered when indicated by medical history or local guidelines

Thank you

 Any questions?