Plasma Transfusion for INR 1.5 Before Appendectomy
A patient undergoing appendectomy with an INR of 1.5 does not require fresh frozen plasma transfusion. This INR level does not predict bleeding risk in patients not on vitamin K antagonist therapy, and plasma transfusion at this threshold provides no hemostatic benefit while exposing the patient to unnecessary transfusion-related risks 1, 2.
Evidence-Based Rationale
INR Does Not Predict Bleeding Risk in This Context
- The INR was designed and validated exclusively for monitoring patients on vitamin K antagonist (warfarin) therapy, not as a general predictor of bleeding risk 1.
- A systematic review of 79 studies found weak or no association between INR and bleeding risk when used for pre-procedural bleeding prediction 3.
- In critically ill patients with INR 1.5-3.0 undergoing invasive procedures, no difference in bleeding complications occurred whether FFP was given prophylactically or withheld 4.
Plasma Transfusion is Ineffective at INR 1.5
- Emerging evidence demonstrates that transfusing plasma for an INR ≤1.5 does not confer hemostatic benefit 2.
- In patients with minimally prolonged INRs (1.5-2.5), plasma transfusion resulted in INR correction to <1.5 in only 54% of cases, with no difference in hemoglobin drop compared to no transfusion 5, 4.
- The change in INR per unit of FFP can be predicted by pretransfusion INR, and only 50% of patients with INR 1.7 show significant change with FFP transfusion 6.
Guideline Recommendations Against Routine Plasma Use
- The Surviving Sepsis Campaign guidelines recommend against using fresh frozen plasma to correct clotting abnormalities in the absence of bleeding or planned invasive procedures 1.
- The American College of Surgeons recommends prothrombin complex concentrate (PCC) over FFP for life-threatening bleeding or urgent surgical procedures, not for mild INR elevations 7.
- International consensus guidelines state that correction of coagulopathy should not delay procedures, and mild to moderate coagulation defects (INR <2.5) do not require correction 1.
Clinical Approach for Appendectomy
Proceed with Surgery Without Plasma
- Proceed directly to appendectomy without plasma transfusion for INR 1.5 1, 3.
- This INR level represents minimal prolongation that does not increase surgical bleeding risk in patients not on anticoagulants 1.
Address Underlying Cause if Needed
- If the patient has been on warfarin, consider vitamin K 1-10 mg IV if reversal is deemed necessary, though this is rarely required for INR 1.5 1.
- If liver disease is suspected as the cause, recognize that plasma transfusion is even less effective and the INR does not predict bleeding risk in cirrhosis 1, 8.
- Vitamin K deficiency patterns can be corrected with vitamin K rather than plasma 8.
Common Pitfalls to Avoid
- Do not delay surgery to administer plasma or wait for INR "correction" - this exposes patients to transfusion risks (TRALI, allergic reactions, volume overload) without proven benefit 7, 4.
- Avoid ordering INR as a routine pre-operative screen in patients not on anticoagulants, as it leads to unnecessary interventions 1.
- Do not apply INR thresholds derived from warfarin monitoring studies to non-anticoagulated surgical patients 1.
When Plasma Might Be Considered
- Active bleeding during surgery that is clinically significant 1, 7.
- Supratherapeutic INR (>3.0) in a patient on warfarin, though PCC is preferred over FFP 1, 7.
- Life-threatening bleeding with severe coagulopathy (INR >1.5 times normal with PTT >1.5 times normal), though this scenario is distinct from pre-operative INR 1.5 1.