Using phenylephrine in spinals

skipaway · Jul 9, 2005

How many of you have ever used phenylephrine in your spinal mixture? Someone at my clinical site (a CRNA who has been practicing for many years) mentioned that has added 5mg of phenylephrine to a spinal mixture and it significantly prolonged the length of the block (as long as 12 hours!). He couldn't remember the local he mixed it with, and I looked in several of my reference books. Can't seem to find anything, so he seems to think it was one of those things people did a long time ago and never documented in the literature. Anyone have any experience with this?

Do you mean 5mcg? When I trained we rarely used Phenylephrine, it did extend the block but not as long as 12 hours. I had maybe 2 or 3 patients who received it. No other experiences to share.

heartICU · Jul 9, 2005

Do you mean 5mcg? When I trained we rarely used Phenylephrine, it did extend the block but not as long as 12 hours. I had maybe 2 or 3 patients who received it. No other experiences to share.

Nope, 5mg. According to this particular CRNA, it really was 5mg, and he was skeptical of the high dose when he did it, but apparently it did prolong the block. Can't seem to find anyone else who has done it or any research to back it up, though.

sproutsfriend · Jul 9, 2005

Look in the Mass General book and it will confirm that 5 mg of phenylephrine is utilized. I've used it a number of times and it works very well.

heartICU · Jul 10, 2005

Look in the Mass General book and it will confirm that 5 mg of phenylephrine is utilized. I've used it a number of times and it works very well.

How long do your blocks last?

kungfucaveman · Jul 10, 2005

How long do your blocks last?

No first hand experience here, but the literature states that when tetracaine is mixed with phenyephrine (5mg )the duration can be 406 (+/- 63) minutes for regression of the block to L1.

heartICU · Jul 10, 2005

No first hand experience here, but the literature states that when tetracaine is mixed with phenyephrine (5mg )the duration can be 406 (+/- 63) minutes for regression of the block to L1.

Can you provide a reference for this?

kungfucaveman · Jul 10, 2005

Can you provide a reference for this?

Miller's Anesthesia (6th edition) - volume 2 -page 1666. Table 43-3. Hope this helps.

heartICU · Jul 10, 2005

Miller's Anesthesia (6th edition) - volume 2 -page 1666. Table 43-3. Hope this helps.

Thanks!

London88 · Jul 10, 2005

I used tetracaine with 3mg of phenylephrine to do a B/L total knee, and it worked beautifully.We started the case at 8:30a and got done at 12;45p. The pt was very comfortable and had no complaints. My MDA did not expect the spinal to last this long because our plan was to switch to a general after four hours if the spinal was wearing off. It was his idea to use the phenylephrine, and he told me that it usually lasts longer than epi. I definitely plan to incorporate this into my practice when I get done.

gotosleepnow · Jul 11, 2005

I used tetracaine with 3mg of phenylephrine to do a B/L total knee, and it worked beautifully.We started the case at 8:30a and got done at 12;45p. The pt was very comfortable and had no complaints. My MDA did not expect the spinal to last this long because our plan was to switch to a general after four hours if the spinal was wearing off. It was his idea to use the phenylephrine, and he told me that it usually lasts longer than epi. I definitely plan to incorporate this into my practice when I get done.

:coollook: do you know of any bad adverse effects? 3mg huh..........sounds good if it works like you say......i could really use this. saves money too@!!! thanks for the post.

mwbeah · Jul 11, 2005

anesth analg. 1986 apr;65(4):365-9.related articles, links

prolongation of lidocaine spinal anesthesia with epinephrine and phenylephrine.

leicht ch, carlson sa.

the effect of vasoconstrictors on the duration of lidocaine spinal anesthesia is controversial. we conducted a double-blind study of 28 neurologically normal asa class i or ii patients to determine the effect of vasoconstrictors (epinephrine and phenylephrine) on the duration of lidocaine spinal anesthesia. the patients were randomized into three groups. all patients received 1.2 mg lidocaine per inch body height, mixed with 0.5 ml of test solution. group 1 patients received lidocaine plus 0.5 ml normal saline; group 2 patients received lidocaine plus 0.3 mg epinephrine; group 3 patients received lidocaine plus 5 mg phenylephrine. segmental sensory blockade was assessed by pinprick at 2-min intervals for the first 20 min and then every 5 min thereafter. mean highest level was between t-2 and t-3 for all 3 groups. time from injection to highest sensory level was similar in groups 1 and 3, 11.6 +/- 3.57 and 12.0 +/- 5.10 min, respectively, but was significantly prolonged in group 2, 18.1 +/- 4.33 min. time for regression by two sensory dermatomes were significantly prolonged in both groups 2 and 3, 102.9 +/- 18.1 and 105.7 +/- 33.1 min, respectively, compared to 78.1 +/- 12.6 min in group 1. times for regression to t-12 was also significantly prolonged in both groups 2 and 3, 153.7 +/- 27.6 and 156.8 +/- 26.7 min, respectively, compared to 117.71 +/- 10.0 min in group 1. in the doses used in the present study, both epinephrine and phenylephrine significantly prolong the duration of lidocaine spinal anesthesia. anesth analg. 1984 feb;63(2):134-8.related articles, links

vasoconstrictors in spinal anesthesia with tetracaine--a comparison of epinephrine and phenylephrine.

concepcion m, maddi r, francis d, rocco ag, murray e, covino bg.

a randomized double-blind study was conducted in 50 orthopedic patients to determine the effect of epinephrine and phenylephrine on the anesthetic properties of intrathecally administered tetracaine. two doses of each vasoconstrictor agent were studied: 0.2 mg of epinephrine, 0.3 mg of epinephrine, 1 mg of phenylephrine, and 2 mg of phenylephrine. the results show that both vasoconstrictor agents in the doses used significantly prolong duration of sensory anesthesia and motor blockade produced by the subarachnoid administration of tetracaine. at equipotent doses no differences existed between the ability of epinephrine and phenylephrine to prolong the duration of spinal anesthesia produced by tetracaine.