hematoma following epidural analgesia in a patent receiving unfractionated
heparin for thromboprophylaxis.
Sandhu H, Morley-Foster P, Spadafora
S. Regional Anesthesia & Pain Medicine. 25 (1): 72-5, 2000
Commentary by Peter
[see abstract below]
Low Dose Heparin and Neuraxial Block
In their recent paper, Sandhu et al. note that risk factors for hematoma
formation after epidural anesthesia include coagulopathies (congenital
and acquired), ankylosing spondylitis, traumatic epidural insertion, old
age, and epidural catheter manipulation while anticoagulated. The risk
of epidural hematoma in the absence of heparin is estimated to be 1:150,000.
Following generally accepted recommendations at the time, the epidural
catheter was placed two hours after the initial dose of 5000U of standard,
unfractionated heparin for thromboprophylaxis. However, this timing coincides
with the peak effect of this common heparin regime, and current American
Society of Regional Anesthesia (ASRA) guidelines now recommend delaying
subcutaneous heparin until one hour after neuraxial block placement. These
new guidelines go on to suggest that catheter removal occurs one hour
prior to the next planned dose of standard heparin, or 2-4 hours after
the last given dose of standard heparin. Although there was a delay of
almost 24 hours of recognizing the presence of aberrant leg weakness,
this patient fortunately had a good outcome after her subsequent decompression
laminectomy for epidural hematoma. The author cautions that unexpected
sensory/motor symptoms, with or without back pain, are crucial markers
that must trigger the immediate search for, and removal of, an epidural
Liu et al.,  in a significant review of standard (unfractionated) heparin
and neuroaxial block note that the drug's half life (T1/2) is both dose-
and molecular-size dependant; and increases disproportionately with increasing
||T1/2 IV Heparin
The administration of low dose (5000 u) subcutaneous [sc.] Heparin q12h
for deep venous thromboprophylaxis usually does not elevate the aPTT.
But this result can be unpredictable, and 15% of patients can develop
an elevated aPTT, which is usually less than 1.5 times the normal level.
In addition 2-4% patients achieve an aPTT that is in the therapeutic range.
In spite of this, there are several published series, totaling over 9,000
patients who received mini-dose heparin prophylaxis without developing
spinal hematomas. And, like Sandhu, many anesthesiologists believe that
this therapy does not contraindicate neuraxial block, but the risk of
hematoma may be reduced by delaying the initiation of heparin therapy
until after the block.
Horlocker , in a review article in a new journal, also examines neuraxial
anesthesia and anticoagulation, including the use of standard heparin.
I mention this journal because, like Survey of Anesthesiology, it attempts
to summarize current anesthesia knowledge for busy anesthesiologists.
Instead of selected abstracts, Current Anesthesiology Reports presents
several review articles, covering two major areas of anesthesia, in each
of its 6 bimonthly issues.
On the topic of neuraxial anesthesia and anticoagulants, 1998 was a banner
year for review articles on specific classes of drugs, many of which appeared
in the last issue of the ASRA journal that year. In addition to Liu's
article, Horlocker  examined low molecular weight heparin (LMWH) while
Enneking  reviewed oral anticoagulants and Urmey  antiplatelet drugs
in separate articles, which contained the appropriate ASRA recommendations.
- Liu SS, Mulroy MF. Neuraxial anesthesia and analgesia in the presence
of standard heparin. Regional Anesthesia & Pain Medicine. 23(6
Suppl 2):157-63, 1998
- Horlocker TT. Neuraxial Anesthesia and Anticoagulation. Current
Anesthesiology Reports. 2 (2): 99-105. 2000
- Horlocker TT, Wedel DJ. Neuraxial block and low-molecular-weight heparin:
balancing perioperative analgesia and thromboprophylaxis. Regional
Anesthesia & Pain Medicine. 23(6 Suppl 2):164-77, 1998
- Enneking FK, Benzon H. Oral anticoagulants and regional anesthesia:
a perspective. Regional Anesthesia & Pain Medicine. 23(6 Suppl
- Urmey WF, Rowlingson J. Do antiplatelet agents contribute to the development
of perioperative spinal Hematoma. Regional Anesthesia & Pain Medicine.
23(6 Suppl 2):146-51, 1998
Epidural hematoma following epidural
analgesia in a patent receiving unfractionated heparin for thromboprophylaxis.
Sandhu H, Morley-Foster P, Spadafora S.
Regional Anesthesia & Pain Medicine. 25 (1): 72-5, 2000
No abstract available.