DCHZ's Discussion #2: "you don't add epinephrine to ropivacaine"

[dchz]

So I got pimped by one of my fav attendings the other day. He told me that one could add epinephrine to a bupivacaine block but not to a ropivacaine block because ropivacaine is a vasoconstrictor. I've heard this notion before, but it always struck me as odd, how would a local anesthestic that blocks sodium channels be a vaso constrictor???!?! specially since bupivacaine has such a similar structure and obviously vasodilates?? (TL;DR at bottom)

Ropivacaine:

Bupivacaine:

Original Kopaz article that showed lower blood flow with ropiv compared to bupiv:

Kopacz DJ, Carpenter RL, Mackey DC. Effect of ropivacaine on cutaneous capillary blood flow in pigs. Anesthesiology. 1989;71:69–74.

I'm not sure if this data is enough to make me believe that ropivacaine is a vasoconstrictor. But cocaine, another local anesthetic, is definitely a vaso constrictor.

Cocaine:

But the vasoconstriction is probably due to the side chain.

3 years after kopaz, this guy in sweden named Cederholm actually did the same study but he added epi to ropiv:

Cederholm I, Evers H, Löfström JB. Skin blood flow after intradermal injection of ropivacaine in various concentrations with and without epinephrine evaluated by laser Doppler flowmetry. Reg Anesth. 1992;17:322–8.

But his study actually showed that Epi + ropiv lowers blood flow compared to ropiv alone.

So in my mind this at least proves that epi + ropiv vaso constricts more than ropiv alone. But does it really matter clinically?


Hickey R, Blanchard J, Hoffman J, Sjovall J, Ramamurthy S. Plasma concentrations of ropivacaine given with or without epinephrine for brachial plexus block. Can J Anaesth. 1990 Nov;37(8):878-82

This article shows that the plasma concentration of ropiv is no different during subclavian blocks whether or not if you have epi added. but the study is small and the data is all over the place, not convincing to me.

Schoenmakers KP, Fenten MG, Louwerens JW, Scheffer GJ, Stienstra R. The effects of adding epinephrine to ropivacaine for popliteal nerve block on the duration of postoperative analgesia: a randomized controlled trial. BMC Anesthesiol. 2015 Jul 10;15:100. doi: 10.1186/s12871-015-0083-z.

This article shows that mean time to asking for first opioid, which is clinically what really matters, does not chang with epi vs no epi in ropiv blocks.

TL;DR:
- Evidence for ropiv as a vaso constrictor is weak, it just doesn't vasodilate as much as bupiv.
- However, clinically, it doesn't seem to affect the duration of blocks clinically if you add epi to ropiv.

Finally, epi as marker for intra vascular injection marker has its own merits. However, with good ultrasound technique, it feels like that might be marginal at best.

Thoughts? all discussions welcome. What do you do in your practice, why? Does any of the above info persuade you to think about changing your practice?

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[BLADEMDA]

Therefore, adding epinephrine to ropivacaine may be a useful strategy to reduce systemic ropivacaine toxicity.

Arterial and Venous Pharmacokinetics of Ropivacaine with and without Epinephrine after Thoracic Paravertebral Block | Anesthesiology | ASA Publications

 

[dchz]

Therefore, adding epinephrine to ropivacaine may be a useful strategy to reduce systemic ropivacaine toxicity.

Arterial and Venous Pharmacokinetics of Ropivacaine with and without Epinephrine after Thoracic Paravertebral Block | Anesthesiology | ASA Publications

Def fair point, the counter point would be that the instances of this is so much lower given that we use ultrasound guidance, is it worth adding the epi??

 

[BLADEMDA]

J Anesth. 2014 Aug;28(4):631-4. doi: 10.1007/s00540-013-1784-4. Epub 2014 Jan 29.
Effects of adding epinephrine on the early systemic absorption kinetics of local anesthetics in abdominal truncal blocks.
Kitayama M1, Wada M, Hashimoto H, Kudo T, Takada N, Hirota K.
Author information

Abstract
We evaluated the pharmacokinetics of ropivacaine following rectus sheath block (RSB) and transversus abdominis plane (TAP) block with or without epinephrine. A total of 26 adult patients undergoing lower abdominal surgery with RSB (=RSB trial) and another 26 adult patients undergoing open prostatectomy with TAP block (=TAP trial) were enrolled. Patients were randomly assigned to receive either a mixture of 0.75 % ropivacaine 13.2 mL with 1 % plain lidocaine 6.8 mL (TAP-E(-) and RSB-E(-) groups) or a mixture of 0.75 % ropivacaine 13.2 mL and 1 % lidocaine containing adrenaline (1:100,000) 6.8 mL (TAP-E(+) and RSB-E(+) groups) under general anesthesia. The serum concentrations of ropivacaine were measured using gas chromatography with mass spectrometry. The peak concentration was significantly lower and time to peak concentration was significantly longer in the TAP-E(+) group than in the TAP-E(-) group (P < 0.05 and <0.01, respectively), while there were no significant differences in these parameters between the RSB-E(+) and RSB-E(-) groups. These results indicate that epinephrine attenuates the early phase of local anesthetic absorption from the injected site in TAP blocks, but not RSB.

 

[BLADEMDA]

Def fair point, the counter point would be that the instances of this is so much lower given that we use ultrasound guidance, is it worth adding the epi??

Send to



Eur J Anaesthesiol. 2012 May;29(5):235-8. doi: 10.1097/EJA.0b013e328350b0d5.
Potentially toxic concentrations in blood of total ropivacaine after bilateral transversus abdominis plane blocks; a pharmacokinetic study.
Torup H1, Mitchell AU, Breindahl T, Hansen EG, Rosenberg J, Møller AM.
Author information

Abstract
CONTEXT:
Elevated blood levels of lidocaine and ropivacaine have been described after transversus abdominis plane (TAP) block.

OBJECTIVE:
To investigate the pharmacokinetic profile of ropivacaine after bilateral TAP blocks.

DESIGN:
Prospective observational pharmacokinetic study.

SETTING:
University teaching hospital in Copenhagen, Denmark.

PATIENTS:
Twenty-one adult patients presenting for abdominopelvic surgery with bilateral TAP blocks were enrolled.

PROCEDURES:
Ultrasound-guided TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v (total dose 200 mg). Blood was sampled at 0, 10, 30 and 60 min after TAP blocks.

MEASURES:
Total and free peak blood concentrations (Cmax) of ropivacaine.

RESULTS:
Data were analysed from N = 18 patients. The median dose of ropivacaine was 2.7 mg kg(-1) (range: 1.9-4.2 mg kg(-1)). Median total ropivacaine concentrations were 1.0, 1.6 and 1.7 μg ml(-1) at 10, 30 and 60 min, respectively. Six patients (33%) had Cmax values above 2.2 μg ml(-1) and the highest concentration measured was 5.1 μg ml(-1). One patient had a 33% drop in mean arterial blood pressure.

CONCLUSION:
TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v gave rise to potentially toxic peak blood concentrations of total ropivacaine in one-third of the patients.

 

[BLADEMDA]

Br J Anaesth. 2010 Dec;105(6):853-6. doi: 10.1093/bja/aeq255. Epub 2010 Sep 22.
Plasma ropivacaine concentrations after ultrasound-guided transversus abdominis plane block.
Griffiths JD1, Barron FA, Grant S, Bjorksten AR, Hebbard P, Royse CF.
Author information

Abstract
BACKGROUND:
The transversus abdominis plane block is a novel technique involving injection of local anaesthetic between the internal oblique and the transversus abdominis muscles of the abdominal wall. It is possible that injection of a large dose of local anaesthetic into a relatively vascular plane may result in toxic concentrations. One previously published study examined plasma lidocaine concentrations after transversus abdominus plane block and showed potentially toxic plasma concentrations. Although ropivacaine is most commonly used for this technique, plasma concentrations of ropivacaine after this block have not been reported previously.

METHODS:
Adult female patients undergoing elective open gynaecological surgery received bilateral ultrasound-guided transverse abdominal plane blocks before surgical incision (3 mg kg(-1) of ropivacaine diluted to 40 ml). Venous blood was collected each 15 min for the first hour, each 30 min for the second hour, and then at 3, 4, 12, and 24 h post-block.

RESULTS:
Twenty-eight patients were recruited. The mean (sd) peak total ropivacaine concentration occurred 30 min post-injection and was 2.54 (sd 0.75) µg ml(-1). The highest measured concentration was 4.00 µg ml(-1), also 30 min post-injection. Mean total concentrations remained above 2.20 µg ml(-1) for up to 90 min post-injection. The mean unbound peak venous concentration was 0.14 (0.05) µg ml(-1), and the peak was 0.25 µg ml(-1).

CONCLUSIONS:
Transversus abdominus plane block using 3 mg kg(-1) of ropivacaine produces venous plasma concentrations that are potentially neurotoxic, although broadly consistent with plasma levels found after injection at other comparable sites.

 

[dchz]

Well @BLADEMDA voting for yes to epi, what dose would you use? 1:200k?

 

[anbuitachi]

Is there a reason to why people add epi to blocks and not norepinephrine?

 

[dchz]

Is there a reason to why people add epi to blocks and not norepinephrine?

Someone will respond with something about skin/tissue nercosis.

Also norepi isn't an effective marker for intravascular injection imo.

 

[BLADEMDA]

Well @BLADEMDA voting for yes to epi, what dose would you use? 1:200k?

I only add EPI to "field blocks" like TAP, ESP, PECS1 and 2 where the total dosage of local will be at the limits of recommended. The goal of the EPI is to decrease peak and total plasma concentration thereby avoiding any toxicity.

 

[anbuitachi]

Someone will respond with something about skin/tissue nercosis.

Also norepi isn't an effective marker for intravascular injection imo.

Yea but no one is using epi for test dosing w field blocks under ultrasound . And I can't imagine it causing necrosis in those doses

 

[AdmiralChz]

Yea but no one is using epi for test dosing w field blocks under ultrasound . And I can't imagine it causing necrosis in those doses

Infilatrated norepi infusions of just 8-16 mcg/mL cause pretty gnarly localized necrosis. Many of these require phenotolamine (board answer there!) to minimize spread and even surgical interventions. I wouldn’t want to find out what dose IS safe, if any.

 

[leaverus]

in residency we added epi to all of our PNBs, for which we exclusively used ropiv. nowadays I only add it to bupiv.

 

[dchz]

in residency we added epi to all of our PNBs, for which we exclusively used ropiv. nowadays I only add it to bupiv.

Great to know what, but i'm also curious in the why?

 

[BLADEMDA]

Great to know what, but i'm also curious in the why?

I don't typically add Epi to my peripheral nerve blocks when I'm confident peak and plateau blood levels of local will be well below toxic levels. This means a typical dosage of 100-150 mg of Rop or Bup and I don't add the Epi.

But, sometimes I'm using a lot of local at the upper end of the range and the data seems to clearly suggest a better safety profile with the addition of Epi for certain blocks.