American Society of Regional Anesthesia and Pain Medicine November 2017 - 22

Dr Maniker: No. Interscalene catheters have been associated with
phrenic block and respiratory events, even if the initial bolus doses
did not result in symptomatic pulmonary compromise.
Dr Harrington: At this point, the catheter appears to be functioning
well. Although I would usually initiate a low-volume infusion for a
case like this, in this patient I would not start a baseline infusion
but would prefer to first try a patient-controlled intermittent bolus
technique (4 mL 0.2% ropivacaine with a 60-minute lockout).
Dr Pawa: I would leave the catheter in situ and only cautiously
commence an infusion, or administer a low-volume bolus if pain
became an issue overnight. This patient would have continued
administration of low-flow oxygen and vital signs measurement
monitoring throughout.
If yes, what would your infusion strategy be?
Dr Auyong: Options for infusion would be (1) intermittent, lowvolume bolusing of the interscalene catheter as needed (no
continuous rate), (2) infusion of chloroprocaine so any clinical
symptoms of phrenic paralysis would be short lived, or (3) replacing
the interscalene catheter with a more distal brachial plexus
approach such as a suprascapular catheter.
Dr Maniker: If the catheter was used, the infusion should be
initiated with very low volume and in a well-monitored setting.
Dr Harrington: As before: no baseline infusion with a patientcontrolled intermittent bolus (4 mL 0.2% ropivacaine with a
60-minute lockout). Continue multimodal therapy (acetaminophen
plus gabapentin) on a scheduled basis, with oxycodone available
PRN. If this approach was inadequate, I would begin a low-volume
infusion of ropivacaine (4 mL/hr) on top of the patient-controlled
intermittent bolus.
Dr Pawa: I would use infusion of a low-volume, low-concentration
solution such as 0.125% bupivacaine or 0.2% ropivacaine at 4-5
mL/hr.
A low-volume infusion of 0.2% ropivacaine at 4 mL/hr
is initiated, and the patient is transferred to the floor for
observation and supplemental oxygen administration. The
following day, the patient's oxygen saturation has now
normalized and she is prepared for discharge. The surgeon,
after further discussions with cardiology, would like to restart
clopidogrel therapy immediately.
Do you have any concerns sending a patient home with an
interscalene catheter while on clopidogrel? Warfarin? Low
molecular-weight heparin (LMWH)? If you have treated these
differently, why?

Dr Auyong: In general, if patients are on anticoagulation, I
recommend removal of continuous nerve blocks upon discharge
home. However, this patient is now asymptomatic and likely receiving
significant analgesic benefit from the continuous nerve block. It
appears that discharging this functioning continuous block is in
the best interest of the patient. I would discuss the risks, benefits,
and options for analgesia with the patient and if she understood,
would allow discharge home with anticoagulation. Because this is
an interscalene block at a compressible area, I am less concerned
about a small hematoma from the catheter remaining in place and
eventually being removed. It is important that the patient and her
caregiver understand the risks of going home with the nerve block
while anticoagulated. If the patient had a follow-up appointment with
the surgeon within the next few days, I would recommend removal of
the catheter while in the surgeon's office.
Dr Maniker: I would be hesitant to send this patient home with an
interscalene catheter given the risk of symptomatic phrenic paresis
and the impact on pulmonary function. In addition, perineural
bleeding from catheter or its removal would not be recognized
and therefore I would not send the patient home with a catheter if
anticoagulated with clopidogrel or warfarin.
Dr Harrington: I would like to hold clopidogrel until the catheter is
removed. Prophylactic dose LMWH (40 mg/d) would be preferable
and recommended. Although warfarin would be acceptable for a
few days (because of its delayed effect), it doesn't appear to be
indicated in this case.
Dr Pawa: I have major concerns with clopidogrel and warfarin
and indwelling catheters. Once those therapies are reinstituted,
intentional or unintentional catheter removal could be problematic.
Prophylactic LMWH is a once-a-day therapy, and at least planned
catheter removal can be carefully planned 12 hours after last dose.
Following a discussion with the surgeon and cardiologist, the
decision is made to send the patient home with aspirin and
LMWH therapy until the interscalene catheter is removed. The
patient lives three blocks from the hospital, and the patient's
daughter is an internist who vows to monitor the catheter site
closely for any signs of bleeding. The patient is sent home with
an indwelling interscalene catheter. Following a successful
3-day ambulatory infusion, it is now time for the interscalene
catheter to be removed.
What steps or precautions do you normally take at the time of
peripheral nerve catheter removal (eg, pausing infusion, family
member to assist with removal, coached on phone)?
Dr Auyong: Normally, we give instructions for catheter removal
preoperatively and in the recovery room. Additionally, we call the

American Society of Regional Anesthesia and Pain Medicine
2017

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