IV-free sedation may help anxious cataract patients

Cataract surgery with or without intravenous sedation can be a factor in the clinical experience. Moving to sublingual sedation may be the next step in safety and comfort for a demanding patient demographic.

Cleveland-Cataract surgery has evolved from the original striking of an opaque lens with a blunt object to the modern era of phacoemulsification and onward. The procedure continues to be refined and, as one of the safest procedures in medicine, has moved from a hospital to an outpatient setting.

In spite of its safety, most cataract surgeons still routinely use intravenous (IV) sedation and as insurance in case of any other medical emergency that may arise. However, clinical experience with oral anesthesia delivery is showing it may be more effective than IV delivery, and patient pushback may force us to get rid of the “just-in-case IV."

Most cataract surgeries employ the following medications singularly or in some combination: midazolam, fentanyl, ketamine, and propofol.

Ten years ago, our surgical center preferred midazolam and fentanyl. Though these worked well, the opioid also produced some hard-to-predict side effects, such as nausea, that heavily influenced patients’ impression of surgery. Thus we switched to midazolam and ketamine.

Ketamine is known as a dissociative anesthesia that produces an analgesic and sedative effect. Ketamine is commonly used for short surgical procedures as it has rapid induction, analgesia, and amnesia with a short recovery period. Ketamine was found to change patients’ perspective of cataract surgery from something scary to something positive.

Midazolam is commonly utilized for conscious sedation/anxiolysis/amnesia and when used for anesthesia, can reduce the unpleasant emergence reactions caused be ketamine.^{1, 2} Studies have demonstrated that midazolam and ketamine have additive effects on conscious sedation, but not on anesthesia.³

Getting ahead of surgical anxiety

For many years, midazolam and ketamine were administered in the clinic via traditional IV as soon as surgeons entered the operating room. In general, it worked very well.

The one downside was that patients had already been waiting in the operating room, usually looking at the lights and developing anxiety over what was to happen.

If midazolam is not delivered to patients before anxiety hits, it takes an increased amount of drug to calm them. If patients could be given the calming agent while they were still calm, they would more easily remain so. Timing the IV was difficult to assess and coordinate given the quick-acting, quick-diminishing effects of the drug and the fast-paced schedule of a surgical center.

To improve the delivery and timing of the anti-anxiety properties of the drugs, the move was made to an oral administration. A comparison of IV and buccal administration of midazolam and ketamine demonstrate the procedural window for IV delivery is between 2 and 22 minutes following administration, while the procedural window for buccal delivery is between 20 and 60 minutes. Both delivery options have an estimated maximum recovery time of about 95 minutes. 

Buccal, or sublingual administration, allows us to start the drugs earlier and allow the slow onset to prevent the initial anxiety build up. The drugs wear off slower, making it easier to time the surgery with a consistent delivery of sedative.

Initially, I always had an IV started even though I was administering the drug orally. Early in my trial of oral administration a patient presented for cataract surgery on his second eye and asked me why I had to place the IV. I explained that it was security in case of any medical event during surgery.

He asked me if I used it for a medical event on the first surgery, and if I anticipated using it during the second surgery. As my answer was “no” to both questions, he requested that I not start an IV. While nervous, the few thousand previous cases of placing an IV that I never used for medical emergency provided me with the confidence to perform surgery without the IV.

Conscious-sedation troche

Working with Imprimis Pharmaceuticals, John Berdahl, MD, and others, we were able to develop the conscious-sedation troche (MKO Melt) that is composed of 3 mg midazolam, 25 mg ketamine, and 2 mg ondansetron. Ondansetron is used to treat postoperative nausea and vomiting and takes much longer to reach maximum plasma concentration, as well as longer to reach elimination half life than midazolam and ketamamine.⁴ The sublingual troche is easier for patients to manage than holding a sometimes-uncomfortable amount of liquid underneath their tongue.

In general, 90% of cataract patients say surgery on the second eye is worse than the first procedure, even when both surgeries were the same. Thus I try to avoid making any changes to the procedure unless absolutely necessary.

However, once the prototype for the sublingual troche became available, I did offer it to patients undergoing cataract surgery on their second eye as an alternative to an IV.

The small troche is placed sublingually and dissolves in 2 to 5 minutes. Out of 28 patients, 85% preferred not to have an IV when given the option. Once surgery was complete, 80% of those who received the sublingual troche preferred it to the IV they had with the first surgery.

Given the natural bias toward the first surgery, this is already a very strong number. Considering these were our first patients to receive the sublingual troche, and a few felt they were a little too deeply sedated and a few felt the sedation was a little too light, there was something of a learning curve and patient satisfaction rates would be even higher now.

Cost and efficiency

Whenever new technologies are introduced, all ambulatory surgical centers (ASCs) must assess the cost of adopting the technology and how it will impact patient flow.

During the early learning period with IV-free surgery, nurses ran a report comparing the total time a patient is in the clinic for cataract surgery if an IV is administered and if it is not. Mean total patient time in clinic with the IV was 155 minutes, and without IV it was 125 minutes. This significant reduction in time seemed impossible, but we discovered that not having the start an IV meant more time to go over what to expect with the patient, and an overall large gain in efficiency.

The sublingual troche comes in a package of 2 tablets for $25. We calculate that our hard cost for an IV, including the dressings, tubing, needle, medication, cost of storing the medication, etc. is around $10. When the nurse time for starting the IV is included, the cost is closer to that of the troche, but it is still less expensive in hard costs.

However, there are many intangibles that should be considered.

We have patients that choose not to have cataract surgery simply because they have a phobia of IVs. There are patients that choose us because someone told them we offer IV-free cataract surgery.

Finally, by shaving ASC time from each patient, it is possible to perform surgery on at least one additional patient per day, or provide them with better care and a better experience. All these things add up to making IV-free surgery more favorable in the long run.

Evolution and progress

Innovation in almost all aspects of medicine has been phenomenal. Procedures regularly evolve to be safer, less invasive, and more comfortable for the patient. While cataract surgery has already been an exceptional example of progress, moving to sublingual sedation is the next step in safety and comfort for a very demanding patient demographic.

Disclosures:

William F. Wiley, MD
P: 440/526-1974
E: wiley@cle2020.com
Dr. Wiley is in private practice and medical director of the Cleveland Eye Clinic.

References:

1. Toft P, Romer U. Comparison of midazolam and diazepam to supplement total intravenous anaesthesia with ketamine for endoscopy. Can J Anaesth. 1987;34:466-469.

2. Cartwright PD, Pingel SM. Midazolam and diazepam in ketamine anaesthesia. Anaesthesia. 1984;39:439-442.

3. Hong W, Short TG, Hui TW. Hypnotic and anesthetic interactions between ketamine and midazolam in female patients. Anesthesiology. 1993;79:1227-1232.

4. Roila F, Del Favero A. Ondansetron clinical pharmacokinetics. Clin Pharmacokinet. 1995;29:95-109.