American Society of Regional Anesthesia and Pain Medicine November 2017 - 49

Table 2: Recommendations for neuraxial techniques in the setting of full anticoagulation for cardiopulmonary bypass.17,20
Coagulopathy

Neuraxial blocks should be avoided in patients with preexisting coagulopathies, regardless of the
etiology.

Traumatic tap

Surgery should be delayed 24 hr in the event of bloody neuraxial instrumentation.

Heparin timing

Systemic heparinization should be delayed at least 60 min after neuraxial instrumentation.

Heparin dosing and reversal

Administer the smallest dose of heparin for the shortest duration possible, as compatible with
therapeutic requirements for cardiopulmonary bypass.

Epidural catheter removal

Catheters should be removed only after normal coagulation has been confirmed, and close monitoring
for epidural hematoma formation should be continued.

required for cardiopulmonary bypass, many anesthesiologists
will place epidural catheters only on the day prior to cardiac
surgery and will insist that surgery be delayed at least 24 hours
in the event of bloody attempts.20 This approach to traumatic
insertion was published by the American Society of Regional
Anesthesia and Pain Medicine in the most recent guidelines for
regional anesthesia in patients receiving antithrombotic therapy
(Table 2).17 Unfortunately, these practice patterns are prohibitive
for institutions that use same-day admit surgery. With respect to
resource management, delaying surgery by 24 hours in the event
of traumatic neuraxial attempts is inefficient for operating room
use and adds costs secondary to prolonged hospitalizations. This
reality has likely played a key role in limiting the application of
neuraxial analgesia to cardiac surgery, particularly in the United
States.

Overall, growing evidence supports the benefits of neuraxial
analgesia in cardiac surgery, including the attenuation of stress
responses, improvements in myocardial perfusion, and superior
pain control with reduced opioid requirements. Potential clinical
benefits include reduced pulmonary complications, renal injury,
and arrhythmias, as well as earlier extubation and shorter ICU
stays. However, no clear mortality data support the use of neuraxial
techniques in this setting.

In addition to bleeding risks and delayed surgery, hypotension
is another potential deterrent for anesthesiologists considering
neuraxial techniques in this population. During the pre-CPB period,
the hemodynamics associated with many of the pathologies that
will, by definition, be encountered in cardiac surgery might not
tolerate the sympathectomy associated with neuraxial blockade.
Additionally, hypotension during the post-CPB period is relatively
common and potentially quite profound, and certain etiologies,
such as vasoplegia syndrome and myocardial stunning, might be
exacerbated by any degree of sympathectomy. Overall, this aspect
of neuraxial analgesia in cardiac surgery has received a limited
amount of investigation.21

Therefore, optimal patient selection is recommended when
considering neuraxial techniques, and the risk factors for epidural
hematoma and hemodynamic instability must be considered for each
patient before pursuing any type of neuraxial blockade. It is also
important for anesthesiologists to continue to optimize perioperative
analgesic regimens through the application of thoughtful multimodal
approaches (eg, acetaminophen, sternal blocks).

Interestingly, from the high spinal data from Lee et al,5 no
statistically significant difference in phenylephrine usage occurred
during the pre-CPB, on-CPB, or post-CPB periods. However, a
statistically significant increase in post-CPB inotrope requirements
occurred in the high spinal group, which has been shown
elsewhere in the literature.22 Conversely, separate work from Lee et
al6 showed that high spinal analgesia results in less β-adrenergic
receptor dysfunction, along with a statistically significant higher
cardiac index in the post-CPB period.

Meanwhile, the risk of spinal cord injury from hematoma remains
somewhat unclear, and evidence is limited and conflicting for the
hemodynamic impacts of neuraxial blockade in these patients.
As such, the application of neuraxial analgesia to cardiac surgery
remains controversial until more definitive evidence becomes
available.

REFERENCES
1.

Davy C. Fast track cardiac surgery pathways: early extubation, process of care,
and cost containment. Anesthesiology 1998;88(6):1429-1433.

Levy JH, Tanaka KA. Inflammatory response to cardiopulmonary bypass. Ann
Thorac Surg 2003;75(2):715-720.

Chaney MA. Intrathecal and epidural anesthesia and analgesia for
cardiac surgery. Anesth Analg 2006;102(1):45-64. doi: 10.1213/01.
ane.0000183650.16038.f6.

Kowaleski S, Seal D, Tang T, et al. Neuraxial anesthesia for cardiac surgery:
thoracic epidural and high spinal anesthesia-why is it different? HSR Proc
Intensive Care Cardiovasc Anesth 2011;3(1):25-28.

Lee TW, Kowalski S, Falk K, et al. High spinal anesthesia enhances antiinflammatory responses in patients undergoing coronary artery bypass graft
surgery and aortic valve replacement: randomized pilot study. PLoS One
2016;11(3):e0149942.

American Society of Regional Anesthesia and Pain Medicine
2017

Table of Contents for the Digital Edition of American Society of Regional Anesthesia and Pain Medicine November 2017