Spinal anesthesia adjuncts

[Cardio2b]

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So, Miller basically says nothing about opioids as adjuncts for spinal anesthesia.

I've used anywhere between 10mcg and 20mcg with, say, 1.4-1.6 ml 0.75% bupivacaine for TKA's/THA's.

The only SPINAL adjuncts that big Miller mentions are epi, phelylephrine, clonidine, and neostygmine.....

Epi in doses of 0.1-0.2 mg are shown to prolong an anesthetic, moreso in lidocaine than bupivacaine.

Clonidine, when scanning the literature seems highly variable. I've looked at some studies showing 15 mcg is better than 30 mcg. Others reference higher doses. The other day I used 75mcg with my bupivacaine spinal.

What cocktails do you guys use?? This seems highly variable and most of the CA1 (even Miller though) level books are non-specific w/r/t dosing. So, frankly, I'm relying heavily on the common practice of various attendings I'm working with.

Anything really work great, from your personal experiences? Say, adding longevity to a bupivacaine spinal for a slow surgeon or an unpredictable duration? Please don't limit this to bupivacaine either. Any adjuncts that you've had particular success with (and a context would be great) are very much welcomed.

Thanks in advance.

 

[psychbender]

I have a staff that absolutely loves tetracaine spinals for very long procedures (20mg tetracaine, plus 2mL D10, plus 200mcg epi makes for a very long block).

 

[imfrankie]

A little fentanyl, little morphine, little epi is all I've ever added. I concur with the tetracaine comment above. I've gotten some scary long blocks with tetracaine/epi/fentanyl. Long enough for the slowest vascular surgeon. Caution with the liquid tetracaine btw--sometimes you can get a dud batch. I go with the powder and reconstitute myself.

 

[Arch Guillotti]

Try switching from the heavy stuff to .5% iso, I think it has much less hemodynamic lability.

 

[IlDestriero]

I've become a fan of clonidine.

 

[jwk]

I have a staff that absolutely loves tetracaine spinals for very long procedures (20mg tetracaine, plus 2mL D10, plus 200mcg epi makes for a very long block).

I haven't done spinals in years, but that seems like an awful lot of volume for an SAB (4.2cc??) Am I missing something? I used to do tons of tetracaine 10-14mg+epi spinals with max 2cc total volume that lasted as long as 6 hrs.

 

[RxBoy]

So, Miller basically says nothing about opioids as adjuncts for spinal anesthesia.

The only SPINAL adjuncts that big Miller mentions are epi, phelylephrine, clonidine, and neostygmine.....

Que?

"Single-Dose Neuraxial Opioids Administration of a single dose of opioid may be efficacious as a sole or adjuvant analgesic agent when administered intrathecally or epidurally. One of the most important factors in determining the clinical pharmacology for a particular opioid is its degree of lipophilicity (versus hydrophilicity) ( Table 87-3 ). Once they have reacted the cerebrospinal fluid (CSF) through direct intrathecal injection or gradual migration from the epidural space, hydrophilic opioids (i.e., morphine and hydromorphone) tend to remain within the CSF and produce a delayed but longer duration of analgesia, along with a generally higher incidence of side effects because of the cephalic or supraspinal spread of these compounds. Neuraxial administration of lipophilic opioids, such as fentanyl and sufentanil, tends to provide a rapid onset of analgesia, and their rapid clearance from CSF may limit cephalic spread and the development of certain side effects such as delayed respiratory depression.[67] The site of analgesic action for hydrophilic opioids is overwhelmingly spinal, but the primary site of action (spinal versus systemic) for single-dose neuraxial lipophilic opioids is not as certain.[68]

The differences in pharmacokinetics between lipophilic and hydrophilic opioids may influence the choice of opioid in an attempt to optimize analgesia and minimize side effects for a particular clinical situation. Single-dose intrathecal administration of a lipophilic opioid may be useful in situations (e.g., ambulatory surgical patients) in which rapid analgesic onset (minutes) combined with a moderate duration of action (<4 hours) and minimal risk of respiratory depression is needed.[69] Single-dose hydrophilic opioid administration provides effective postoperative analgesia and may be useful in patients monitored on an inpatient basis, for whom a longer duration of analgesia would be beneficial.
Single-dose epidural administration of lipophilic and hydrophilic opioids is used to provide postoperative analgesia, with considerations generally being similar to those discussed for single-dose intrathecal administration of opioids. A single bolus of epidural fentanyl may be administered to provide rapid postoperative analgesia; however, diluting the epidural dose of fentanyl (typically 50 to 100 µg) in at least 10 mL of preservative-free normal saline is suggested to decrease the onset and prolong the duration of analgesia, possibly as a result of an increase in initial spread and diffusion of the lipophilic opioid.[70] Single-dose epidural morphine is effective for postoperative analgesia and may decrease postoperative patient morbidity in selected patients. [71] [72] Use of a single-dose hydrophilic opioid may be especially helpful in providing postoperative epidural analgesia when the epidural catheter's location is not congruent with the surgical incision (e.g., lumbar epidural catheter for thoracic surgery). Lower doses of epidural morphine may be required for elderly patients and thoracic catheter sites. Commonly used dosages for intrathecal and epidural administration of neuraxial opioids are provided in Table 87-4 .

An extended-release formulation of (single-dose) epidural morphine encapsulated within liposomes that results in up to 48 hours of analgesia has recently been introduced.[73] There are some precautions in using this newer formulation of epidural morphine. To resuspend the particles immediately before withdrawal from the vial, the vial should be gently inverted with avoidance of aggressive or excessive agitation. Concurrent administration of liposomal extended-release morphine and local anesthetics may increase peak concentrations of morphine. Accordingly, the manufacturer has recommended that clinicians increase the interval between administration of local anesthetic (including test doses) and liposomal extended-release morphine to at least 15 minutes to minimize this pharmacokinetic interaction. In addition, because the liposomal extended-release morphine does not contain any bacteriostatic agents, it should be administered within 4 hours after withdrawal from the vial. Finally, as with traditional single-dose neuraxial opioids, clinicians should administer a lower dose of liposomal extended-release morphine to the elderly or those with decreased physiologic reserve or coexisting disease. At this time, liposomal extended-release morphine has not been studied or approved in pediatric patients." Miller Anesthesia 7th Edition

 

[imfrankie]

I haven't done spinals in years, but that seems like an awful lot of volume for an SAB (4.2cc??) Am I missing something? I used to do tons of tetracaine 10-14mg+epi spinals with max 2cc total volume that lasted as long as 6 hrs.

reconstituting powdered tetracaine with the sugar water reduces your volume

 

[dhb]

I've become a fan of clonidine.

Me too, 15-30 mcg is fine you'll see some delayed hypotension which is well tolerated.