W. Gogarten et al., REGIONAL ANESTHESIA AND THROMBOEMBOLISM P ROPHYLAXIS ANTICOAGULATION/, Anasthesiologie und Intensivmedizin, 38(12), 1997, pp. 623-628
Performing regional anaesthetics in patients who have or will receive
some form of anticoagulation is still discussed controversially. Howev
er, spinal or epidural anaesthesia is considered safe during low-dose
therapy with unfractioned or low molecular weight heparins as long as
the following time intervals between administration of heparin and spi
nal/epidural puncture or removal of the catheter are carefully taken i
nto account, After unfractioned heparin, placement of a needle or cath
eter and removal of the epidural catheter should be delayed for 4 hour
s, A subsequent injection of unfractioned heparin can be administered
after 1 hour, This includes intraoperative intravenous full heparinisa
tion, provided ACT is carefully monitored, In low molecular weight hep
arins (LMWH), due to the different pharmacokinetics and pharmacodynami
cs, longer time intervals are necessary in order to avoid spinal/epidu
ral bleeding complications; After a single subcutaneous injection, pla
sma levels of LMWH peak after 4 hours and 50% of peak levels can still
be detected after 12 hours, therefore a spinal/epidural puncture or c
atheter removal should be delayed for 10-12 hours, Subsequent injectio
ns of LMWH should occur at least 4 hours later due to their fibrinolyt
ic activity, Routine clotting assays are not necessary, However, if th
erapy with unfractioned or LMWH has been administered for more than 5
days, a thrombocyte count should be performed to exclude heparin-induc
ed thrombocytopenia. In order to minimize bleeding complications durin
g regional anaesthetic techniques, care should be taken to avoid a tra
umatic puncture and to postpone surgery, if a bloody tap occured, Alte
rnatively, catheters can be placed the night before surgery, Regional
anaesthesia in patients with full anticoagulation with either heparin
or vitamin K antagonists remains contraindicated.