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Does sublingual sedation make sense for cataract surgery?
John P. Berdahl, MD, Chris Bender, CRNA, and Kathryn M. Hatch, MD, weigh the advantages and disadvantages of the MKO Melt.
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Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
As modern cataract surgery has moved to topical anesthesia, there have been efforts to make even the anesthesia process less invasive. This month, John P. Berdahl, MD, Chris Bender, CRNA, and Kathryn M. Hatch, MD, discuss the merits of an innovative method of anesthesia that does not require an IV. We hope you enjoy the discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
Sublingual sedation a patient-friendly approach to ocular anesthesia
Cataract surgery has a rich tradition of incredible innovation; however, innovation in ocular anesthesia has been less dramatic. The preferred method of anesthesia gradually transitioned from retrobulbar anesthesia to topical anesthesia with IV sedation as phacoemulsification became the standard surgical technique. The choice of sedation is usually determined by the preference of the attending anesthesia provider or ophthalmologist and varies widely. Yet, modern cataract surgery has evolved, and now one of the greatest pain points is patient IV access.
One recent advance is the MKO Melt (Imprimis Pharmaceuticals), which is a sublingual, quickly dissolving tablet given preoperatively and allows for monitored anesthesia care without the need for IV access in most patients. Each tablet contains 3 mg midazolam, 25 mg ketamine and 2 mg ondansetron. The midazolam provides sedation and some amnesia. The ketamine provides sedation, analgesia, mild euphoria and a “ketamine stare,” which allows patients to tolerate the bright microscope lights well. The ondansetron provides an anti-nausea effect. The melt dissolves in about 2 minutes with peak sedation after about 20 minutes, lasting up to 1 hour after sublingual placement. One or two melts are given preoperatively, and patients are relaxed before arrival in the OR. The MKO Melt stays ahead of patients’ anxiety and pain. Postoperatively, patients recover quickly, and the medications are quickly metabolized.
In our practice, we have used the melt in well more than 10,000 patients, and it has become our standard approach. Patients and nursing staff much prefer the melt to IV sedation. In a survey done by Bill Wiley, MD, 75% of patients preferred the melt to IV sedation and 85% said the anesthesia effect was “just right.” We still have monitored anesthesia care with an anesthesia provider who bills for services. On the rare occasion that we need IV access after starting the case (less than one in 1,000 cases), our anesthetist simply starts an IV. Preoperatively, we assess each patient to determine if an IV is needed. We start an IV preoperatively in about 5% of our patients, which usually is not used and remains hep-locked.
Patients generally require an IV if:
- They are extremely anxious.
- They drink excessively or use illegal drugs.
- They have severe medical conditions.
- They have psychological issues preventing them from cooperating.
- They have a history of difficult IV access.
- We expect a long or complex surgical procedure.
In a 2008 study done by Sharwood and colleagues, 1% of patients were observed to have intraoperative events requiring intervention, three for bradycardia and one for hypotension. All had uneventful recovery, and all were discharged home. This is why a preoperative evaluation and placing a hep-lock IV may be helpful in high-risk patients. Conversely, more complex anesthesia protocols can carry more risk while no sedation techniques increased risk.
In our practice, we find an acceptable level of risk in performing cataract surgery with sublingual sedation without an IV. Studies suggest making an anesthetic regimen more complicated does not inherently make it safer and, in some instances, creates more risk. Of the more than 10,000 cases we have performed using the MKO Melt, 95% do not have IVs in place. Only 1% of the patients who do have IVs placed actually have IV medication administered. Starting an IV in the OR during a case is a rare occurrence. We have had no instances in which we wanted to establish IV access intraoperatively and could not. In addition to the safety and efficacy of the MKO Melt, it definitively provides a better patient experience.
- References:
- Chen M, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2014.06.027.
- Sharwood PL, et al. Clin Exp Ophthalmol. 2008;doi:10.1111/j.1442-9071.2009.01924.x.
- Vann MA, et al. Anesthesiology. 2007;doi:10.1097/01.anes.0000278996.01831.8d.
- For more information:
- John P. Berdahl, MD, can be reached at Vance Thompson Vision, 3101 W. 57th St., Sioux Falls, SD 57108; email: john.berdahl@vancethompsonvision.com.
Disclosures: Bender and Berdahl report financial disclosures with Imprimis.
Sublingual sedation not for all-comers
Not all patients are the same. Our surgical plan for the cataract patient must not only include the IOL choice and the techniques we will use, such as femtosecond laser-assisted vs. manual phacoemulsification, for example, but it must also include an anesthesia plan. Because no two patients are exactly the same, the anesthesia will likely also need to differ from individual to individual. It is necessary to consider certain physical differences between patients, including weight, size, medical comorbidities and ability to lay flat. Additionally, we have to consider patient expectations and varying levels of anxiety regarding the experience. Some patients want little or no recollection of their surgery while others want to experience and know every detail as it takes place. Some patients fear eye surgery and have significant differences in sensitivity with the thought or act of having their eyes worked on. High levels of anxiety could affect their experience as well as that of the surgeons and could result in reduced ease of completing a case if patients are anxious or uncooperative. “Verbal anesthesia,” or providing constant reassurance for the patient, can be useful in eye surgery, but it is certainly not effective for all.
The MKO Melt, an innovative technology that could prevent the patient from needing an IV at the time of cataract surgery, is not for all-comers. Using one type of anesthesia for all patients who differ in size, medical comorbidities and levels of anxiety is not feasible during cataract surgery. Because the melt is a sublingual medication, its effect and, importantly, timing and degree of onset will vary from patient to patient. It could be difficult to time the effect and the precise moments during cataract surgery when anesthesia is truly needed, rendering a lost effect from the melt. IV anesthesia, on the other hand, is easily titratable with predictable and swift time of onset.
Cataract surgery is generally safe, and problems are rare. However, the rare hypothetical situation in which a patient has a real problem or health crisis during surgery and needs immediate IV access (and you do not have it or may have trouble getting it in a pinch) must be considered. Certainly, patients with significant comorbidities would not be good candidates for surgery without IV access. In the rare scenario of a health crisis, is the MKO Melt substandard of care? Scrambling for IV access seems less than ideal. A more common scenario would be the patient who has a melt in which the anesthesia is not adequate. With IV access, a quick IV push of a milligram of midazolam or even propofol in some centers where available, for example, can quickly solve the temporary problem. If you are a busy cataract surgeon and experience even one patient in whom the surgery must be stopped and IV access obtained, the desired convenience with regular use of the melt might be lost for the day.
Lastly, the cost of the melt is also a factor. IV medications are significantly less expensive. For high-volume cataract surgeons, the cost of the melt is likely to be an important factor to consider.
In summary, the MKO Melt may be ideal for some patients, but it is not for all-comers. IV access is still the gold standard during cataract surgery and allows for ease in titration of anesthesia and intravenous access, which, while rare, may be critical for some patients.
- For more information:
- Kathryn M. Hatch, MD, can be reached at Massachusetts Eye and Ear Waltham, 1601 Trapelo Road, Suite 184, Waltham, MA 02451; email: kathryn_hatch@meei.harvard.edu.
Disclosure: Hatch reports no relevant financial disclosures.