Is a patient on prophylactic aspirin (acetylsalicylic acid) 150mg at increased risk for bleeding complications with spinal anesthesia?

Aspirin 150mg and Spinal Anesthesia Bleeding Risk

A patient on prophylactic aspirin 150mg is NOT at high risk for bleeding complications with spinal anesthesia and can safely proceed with the procedure. 1

Key Guideline Recommendations

Aspirin is explicitly not a contraindication to central neuraxial anesthesia (including spinal anesthesia) if the benefit-risk ratio is favorable and there is no associated abnormality of hemostasis. 1 The French Working Group on Perioperative Haemostasis (GIHP), French Study Group on Thrombosis and Haemostasis (GFHT), and French Society for Anaesthesia and Intensive Care Medicine (SFAR) reached strong agreement on this recommendation in 2018. 1

Aspirin vs. P2Y12 Inhibitors: Critical Distinction

• Aspirin monotherapy carries a very low bleeding risk for neuraxial procedures, unlike P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor). 1

• Central neuraxial anesthesia is absolutely contraindicated in patients on P2Y12 inhibitors unless discontinued 5-7 days prior. 1, 2

• The bleeding risk hierarchy is: P2Y12 inhibitors > dual antiplatelet therapy > aspirin monotherapy. 1

Technical Considerations to Minimize Risk

Single-puncture spinal anesthesia is preferable to epidural anesthesia in patients on aspirin, as it involves less trauma and lower bleeding risk. 1

Essential Safety Requirements

• No concurrent anticoagulation or other hemostatic abnormalities must be present. 1

• Experienced operator performing the technique is mandatory. 2

• Careful postoperative neurological monitoring for 1-2 days to detect any signs of spinal hematoma (back pain, progressive weakness, bowel/bladder dysfunction). 3

Evidence Supporting Safety

Research demonstrates that aspirin continuation during spinal surgery does not increase bleeding risk:

• A 2017 meta-analysis found no increased blood loss during spinal surgery with continued aspirin (95% CI, -111.72 to -0.59; P = .05). 4

• No increase in operative time or postoperative blood transfusion requirements was observed. 4

• A 2024 randomized controlled trial is investigating non-inferiority of aspirin continuation in lumbar spinal surgery, with safety monitoring showing no concerning signals. 5

Common Pitfalls to Avoid

Do not confuse aspirin with P2Y12 inhibitors - the latter are absolute contraindications for neuraxial anesthesia without appropriate discontinuation periods. 1, 2

Do not combine aspirin with other anticoagulants for neuraxial procedures, as this significantly increases bleeding risk. 1

Do not ignore patient-specific bleeding risk factors:

• Age >60 years increases bleeding risk. 6
• History of GI bleeding or peptic ulcer disease. 1
• Concurrent NSAIDs (increases GI bleeding risk 3-6 fold). 7
• Uncontrolled hypertension. 7

Dose-Specific Bleeding Risk Context

While your question asks about spinal anesthesia specifically (where aspirin is safe), it's worth noting the general bleeding risk profile:

• 150mg aspirin carries intermediate GI bleeding risk with an odds ratio of 3.2 (95% CI, 1.7-6.5) compared to 2.3 for 75mg and 3.9 for 300mg. 1

• Lower doses (75mg) reduce bleeding risk by 30% compared to 150mg for systemic bleeding complications. 1, 7

• However, for neuraxial anesthesia, the dose difference between 75-325mg aspirin does not significantly alter the safety profile - all are considered acceptable. 1

Clinical Algorithm

1. Confirm aspirin monotherapy only (no P2Y12 inhibitors, no anticoagulants). 1
2. Assess for additional bleeding risk factors (age, bleeding history, concurrent medications). 6
3. Choose single-puncture spinal over epidural when possible. 1
4. Proceed with spinal anesthesia - aspirin continuation is safe. 1
5. Monitor neurologically for 24-48 hours postoperatively for any signs of spinal hematoma. 3