Anaesthesia, Spinal (Intrathecal)
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2019 Edition
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Anticoagulants and Spinal or Epidural Blocks
Only preservative free medicines may be used.
Larger doses cause block to spread higher, with risks of respiratory depression, hypotension and loss of consciousness.
- Bupivacaine 0.5% (Spinal use)
- Give up to 3 mL according to desired level of block.
- Becomes hypobaric (light) within CSF so block may spread higher than anticipated. - Bupivacaine 0.5% with dextrose (Spinal use)
- Give up to 3 mL according to desired level of block.
- Hyperbaric (heavy) so block spreads according to patient position.
To increase duration of analgesia:
ADD
- Fentanyl, 10-25 mcg (i.e. small amounts).
Caesarean deliveries
Lower doses are required due to physiologic changes of pregnancy:
- Bupivacaine, 0.5% with dextrose, 1.8 mL (9 mg)
AND
- Fentanyl, 10 mcg (0.2 mL).
ANTICOAGULANTS AND SPINAL OR EPIDURAL BLOCKS
- Patients on anticoagulants are at risk of developing a spinal haematoma with subsequent paralysis after a spinal or epidural block.
- These anticoagulants should be stopped before the spinal or epidural is performed according to the guidelines given below.
- In order to encourage safe and quality care of patients, please consult a specialist prior to attempting blocks on patients on anticoagulants.
- There are a range of oral anticoagulation, with each having specific recommendations with regard to neuraxial blocks.
Timing of anticoagulants in patients receiving neuraxial anaesthesia:
| Anticoagulant | Before Neuraxial Block | After Neuraxial block |
| Warfarin, oral | Consult with specialist to stop warfarin. | Restart after neuraxial block performed (do not delay) and epidural catheter removed. Monitor INR daily with indwelling catheter. |
| Unfractionated Heparin, SC | Neuraxial techniques may be performed if total daily dose is <10 000U. Check PTT if higher doses are used. | |
| Unfractionated Heparin, IV | Stop heparin 4-6 hours and check PTT <40 | Wait 1 hour before next bolus/infusion restarted |
| Prophylactic LMWH, SC | 12 hours after last dose | 4 hours after neuraxial block performed and epidural catheter removed. |
| Therapeutic LMWH, SC | 24 hours after last dose | >24 hours and consult a specialist (bleeding risk of surgery should be assessed). |
Note
After neuraxial block or epidural catheter removal, patients should be observed closely for new or progressive neurological symptoms. A spinal haematoma can result in permanent paralysis unless decompressive surgery is performed within 8 hours of paralysis onset.
- Clopidogrel and platelet GPIIb/IIIa inhibitors have variable durations of effects on clotting after stopping these medications.
- Specialist advice should be sought before performing neuraxial blocks on patients receiving these medications.
- For patients on warfarin the use of bridging anticoagulation (giving heparin after warfarin is stopped in preparation for surgery or invasive procedures) remains unsettled.
- Practitioners should exercise careful judgment of competing risks in individual patients.
- Heparin may increase the risk of bleeding.
- Whatever practice is adopted the most important consideration is to ensure that adequate anticoagulation with warfarin is re-instituted once the risk of bleeding is past.
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2024 Edition