The most used anticoagulant drugs in ICU and their relation to regional techniques- from W_Haroop 2013_ Anest_ [35] - UFH, unfractionated heparin; sc, subcutaneous; APTTR, activated partial thromboplastin time ratio; iv, intravenous; LMWH, low molecular weight heparin, NSAIDs, non-steroidal anti-inflammatory drugs; INR, international normalized ratio; CrCl, creatinine clearance_
| Drug | Time to Peak Effect | Elimination Half-Life | Acceptable Time after Drug for Block Performance | Administration of Drug while Spinal or Epidural Catheter in Place | Acceptable Time after Block Performance or Catheter Removal for Next Drug Dose |
|---|---|---|---|---|---|
| UFH sc prophylaxis | <30 min | 1–2 h | 4 h or normal APTTR | Caution by manufacturer | 1 h |
| UFH iv treatment | <5 min | 1–2 h | 4 h or normal APTTR | Caution by manufacturer | 24h |
| LMWH sc prophylaxis | 3–4h | 3–7 h | 12 h | Caution by manufacturer | 34h |
| LMWH sc treatment | 3–4h | 3–7 h | 24 h | Not recommended | 4 h |
| Danaparoid prophylaxis | 4–5 h | 24 h | Avoid (consider anti-Xa levels) | Not recommended | 6 h |
| Danaparoid treatment | 4–5 h | 24 h | Avoid (consider anti-Xa levels) | Not recommended | 6 h |
| Bivalirudin | 5 min | 25 min | 10 h or normal APTTR | Not recommended | 6 h |
| Argatroban | <30 min | 30–35 min | 4 h or normal APTTR | Not recommended | 6 h |
| Fondaparinux prophylaxis | 1–2h | 17–20 h | 36–42 h (consider anti-Xa levels) | Not recommended | 6–12 h |
| Fondaparinux treatment | 1–2h | 17–20 h | Avoid (consider anti-Xa levels) | Not recommended | 12 h |
| NSAIDs | 1–12 h | 1–12 h | No additional precautions | No additional precautions | No additional precautions |
| Aspirin | 12–24 h | Not relevant; irreversible effect | No additional precautions | No additional precautions | No additional precautions |
| Clopidogrel | 12–24 h | 7 days | Not recommended | 6 h | 6 h |
| Prasugrel | 15–30 min | 7 days | Not recommended | 6 h | 6 h |
| Ticagrelor | 2 h | 8–12 h | 5 days | Not recommended | 6 h |
| Tirofiban | <5 min | 4–8h | 68 h | Not recommended | 6 h |
Main limb blocks with their indications, contraindications, and practical concerns from S Stubner Schulz: NYSORA, 2023 [23]_
| Block | Indications | Contraindications | Practical Problems |
|---|---|---|---|
| Interscalene | Shoulder/arm pain | Untreated contralateral pneumothorax |
|
| Cervical paravertebral | Shoulder/elbow/wrist pain | Severe coagulopathy |
|
| Infraclavicular | Arm/hand pain | Severe coagulopathy Untreated contralateral pneumothorax |
|
| Axillary | Arm/hand pain | Local infection at puncture site |
|
| Paravertebral Thoracic Lumbar | Unilateral chest or abdominal pain restricted to few dermatomes | Severe coagulopathy Untreated contralateral pneumothorax |
|
| Femoral or sciatic | Unilateral leg pain | Severe coagulopathy Local infection at puncture site |
|
Special circumstances in critically ill and their consideration - from W_Haroop 2013_ Anest_[35]
| Condition | Description |
|---|---|
| Trauma | Triggered by factors such as tissue trauma, shock, dilution of blood components, low body temperature, increased acidity in the blood, and inflammation, it is advisable to evaluate the possibility of coagulopathy before proceeding with any regional anesthesia technique. |
| Sepsis | Severe sepsis often results in a state that promotes blood clotting. The use of preventive measures against deep vein thrombosis is endorsed in these cases. Septic shock may give rise to a type of coagulopathy characterized by the consumption of clotting factors. Due to the associated risks of epidural abscess and meningitis, systemic sepsis is generally considered a relative contraindication for certain procedures. |
| Uremia | Coagulopathy resulting from a low platelet count necessitates evaluating both the quantity and functionality of platelets. The administration of DDAVP can enhance platelet function. In patients with chronic kidney disease undergoing dialysis, it’s important to consider any remaining anticoagulant effects post-dialysis. |
| Liver Failure | The liver produces all clotting factors except for factor VIII. In cases of liver failure, it’s crucial to evaluate any disturbances in blood clotting. Issues like a reduced platelet count and impaired platelet function may occur. It’s essential to both assess and address any coagulation disorders in this context. |
| Massive Transfusion | Changes in blood clotting resulting from the dilution and depletion of clotting factors call for an evaluation of coagulopathy. This assessment is best conducted once bleeding has been managed and the patient has stabilized. Additionally, assessing platelet functionality is necessary after administering platelet transfusions. |
| Disseminated Intravascular Coagulopathy | The abnormal triggering of the blood clotting process results in a condition known as consumptive coagulopathy. In cases of Disseminated Intravascular Coagulopathy (DIC), performing neuraxial blockade is considered unsafe. Therefore, when considering peripheral blocks, they should be administered at sites where compression is feasible. |
Indications, contraindications and practical concerns for epidurals in critically ill patients – from S Stubner Schulz: NYSORA, 2023 [23]_
| Indications | Contraindications | Practical concerns |
|---|---|---|
| Chest trauma | Coagulopathy or current use of anticoagulants during catheter placement and removal | Positioning of patient |
| Thoracic surgery | Monitoring of neurologic function (consider MEP/SSEP) | |
| Abdominal surgery | ||
| Paralytic ileus | ||
| Pancreatitis | Sepsis/bacteremia | |
| Intractable angina | Local infection at the puncture site | |
| Orthopedic surgery or trauma of lower extremities | Severe hypovolemia, Acute hemodynamic instability | |
| Peripheral vascular disease of lower extremities | Obstructive ileus |