EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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May 2012 Perioperative pharmacology February 2011 EW FEATURE 35 Anesthesia preferences in 2012 by Michelle Dalton EyeWorld Contributing Editor AT A GLANCE • Topical anesthesia is preferred over blocks for most cases • Surgery centers affiliated with hospitals are not experiencing issues sourcing sedatives even during the current shortage • Talking to the patient throughout the procedure instills calm • Some patients will be unable to fixate and will need additional anesthesia With a few notable excep- tions, topical anesthesia is the way to go, experts say W hen it comes to cataract surgery, sub- tle differences among surgeons exist, even in anesthesia choices. For most cases, topical anesthesia is preferred over blocks of any kind. William G. Myers, M.D., Myers Center for the Eye, Skokie, Ill., said he's performed "maybe three blocks in the previous 3 years." If a patient candidate is not right for topical, Dr. Myers prefers general anesthesia. Lisa B. Arbisser, M.D., adjunct associate professor, John A. Moran Eye Center, University of Utah, Salt Lake City, and in practice at Eye Sur- geons Associates, Quad Cities, Iowa, administers topical "about 95% of the time," reserving peribulbar block for patients who cannot cooperate for an indirect exam or sustain a fix- ation reflex. "When zonules are missing or the iris must be sewn, the block is used as well," she said. Priscilla Perry Arnold, M.D., also in practice at Eye Surgeons As- sociates (Bettendorf, Iowa location), reserves peribulbar blocks for pa- tients who cannot comprehend verbal instruction or respond appro- priately, who cannot adequately visualize light for fixation, who exhibit extreme sensitivity to light, or for those who are expected to have complex procedures. Conversely, Shameema Sikder, M.D., assistant professor of ophthal- mology, Wilmer Eye Institute, Balti- more, supervises residents and prefers having them use blocks early in resident training. Source: Stockbyte/Stockbyte/Getty Images "In any case of trauma (acute or remote), I'll use retrobulbar over topical," she said, but otherwise in her own cases she uses topical as much as possible. Dr. Myers said he trains residents with topical over blocks, but not until they've got at least 10 cases under their belt. "In routine cases, as long as the surgeon is skilled enough to recog- nize early on when things go wrong, there's no reason not to use topical," Dr. Myers said. "I won't use it in cases of extreme squeezing or unreli- able body movements." Dr. Sikder also prefers to use blocks in cases of white cataracts (and has noticed a distinct trend in smokers, handedness, and intensity of cataract). "At Wilmer, we use a lot of retrobulbar injections. The glaucoma specialists prefer sub-Tenon's, but for residents there's an initial fear with doing a retrobulbar over Tenon's," she said. Although anesthesia prefer- ence is resident-specific, she said typically residents should have about 30 cases performed with "as much block as possible" before she's comfortable introducing topical anesthesia techniques. "With the residents, cases tend to run longer and the block helps that much more," she said. Dr. Arnold said, "Some surgeons who do a lot of combined glaucoma and cataract work will have a differ- ent mix of block-topical use than straight cataract surgeons." No set rules Most surgeons may prefer topical anesthesia to blocks, but each sur- geon will likely have his or her own preferred formula. For example, Dr. Arnold uses topical drops (lidocaine gel) during the immediate pre-op period and then uses intracameral non-preserved lidocaine intraopera- tively. Dr. Arbisser opts to use tetra- caine before a betadine prep, followed by lidocaine gel. "I use Alan Crandall [M.D.]'s mixture of bisulfite preservative-free epinephrine and lidocaine for intra- cameral use," Dr. Arbisser added. "It's less than 0.5 cc through the paracen- tesis, and I use a lot of vocal-local." Dr. Myers starts patients on an- tibiotics 3 days pre-op, then on the day of surgery has the patient re- ceive 1% lidocaine drops, unpre- served without epinephrine. He "paints" 10% betadine on the lids and leaves it on to dry. He then uses lidocaine 4% and betadine 1% once in the operating room, re-preps the lids, and gives one more dose of lidocaine 4% and betadine 1%. "The eye is flooded with 1% povidone-iodine," he said, noting the technique is based on Shimada's description.1 "Gel formulations used before pre-op are potentially danger- ous, as they provide a barrier to povidone-iodine reaching the ocular surface." After the speculum is placed, he repeats both the lidocaine and betadine, and after paracentesis he uses 1.0 mL phenylephrine 1.5%- lidocaine 1% intracameral. If pre- served epinephrine is used, he uses a dilution of 1:4 in balanced salt solution "or preferably, in BSS Plus [Alcon, Fort Worth, Texas]." Dr. Sikder uses a methylparaben- free lidocaine 1% with no added epi- nephrine during a triple procedure involving Descemet's stripping auto- mated endothelial keratoplasty, phaco, and IOL implantation. Her technique during straight cataract surgery differs slightly as well, start- ing with a drop of proparacaine, 5% betadine, and lidocaine gel on the lids. Once that's dried, she wipes away any residue during the next betadine prep. She uses an intracam- eral injection of lidocaine 1% (preservative-free) and epinephrine after paracentesis. Sedation administration There is currently a shortage of vari- ous benzodiazepines in the U.S. (namely, midazolam and diazepam), which may cause problems for some ambulatory surgery centers (ASCs). "At Wilmer, we're affiliated with a hospital and use anesthesiologists for our cataract surgery sedations," Dr. Sikder said. "Anesthesiologists are going to have their own prefer- ences about what they like using." Drs. Arnold and Arbisser's ASC is partly owned by a hospital that has been able to source the drugs from various vendors, and both use dedi- cated anesthesiologists who are re- sponsible for the intravenous meds. Dr. Arbisser gives the patient 1 mg midazolam "right before draping so the patient remains as calm as possi- ble." She will use propofol, but calls it the "ace in the hole" and chooses to use it routinely with peribulbar injections. Dr. Arnold also uses propofol "in small doses" as an "effective way to give some degree of sedation and mild relaxation." She advised sur- geons to be "very careful" with how much sedative is used, as patients who are not as responsive because of the sedative may have periods of "jolting awake," which could result in damage to the eye. continued on page 36