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  • Human Error During Cataract Surgery: Right Patient, Wrong Lens

    By Laura J. Rongé, Contributing Writer

    This article is from May 2006 and may contain outdated material.

    Even the most competent OR team can inadvertently implant the wrong IOL in a patient. Fortunately, there are some simple ways to prevent this serious mistake.

    To err is human. We all make mistakes, as the cliché goes, and a typical day of high-volume cataract surgery is fraught with changing circumstances that could lead to human error. But a simple misstep can result in devastating consequences for you and your patients. It makes sense to look for ways to reduce the risk of one of the obvious accidents: implanting the wrong IOL into the eye.

    Good Examples of Bad Mistakes

    We asked a group of leading ophthalmologists to share their stories and strategies. All of these experts knew of specific cases in which simple errors led to implanting the wrong IOL.

    Patients out of order. “In a typical preop routine, the surgeon chooses the IOL model and power, then the office staff faxes or calls in the order. The IOL is pulled and labeled at the ambulatory surgery center. During surgery, the circulating nurse must give the correct IOL to the scrub technician. This sequence creates several opportunities for potential miscommunication and errors,” explained David F. Chang, MD, clinical professor of ophthalmology, University of California, San Francisco, and in private practice, Los Altos, Calif. “On the day of surgery, the order of scheduled patients might be changed for a number of reasons, including transportation delays. It then becomes possible to give patient B the IOL selected for patient A,” he said.

    Jack A. Singer, MD, president, Singer Eye Center in Randolph, Vt., agreed: “Cases I am aware of involved a change in the order of patients on a day with multiple surgeries, with inadequate communication among staff and between staff and surgeon,” he said.

    Douglas D. Koch, MD, professor of ophthalmology, Baylor College of Medicine in Houston, has heard of several cases in which an incorrect IOL was implanted because nurses lining up the lenses for the scheduled patients did not account for scheduling changes, and the surgeon failed to check each lens and the IOL calculation sheet at the time of surgery. “When one patient canceled surgery, that implant was not pulled out, and the absent patient’s implant was therefore implanted in the patient who was next on the surgical schedule. Regrettably, the error was not detected until three patients had been implanted with the incorrect lens,” he said.

    Midsurgery mix-ups. Mistakes are also possible when a decision is made during surgery to change the IOL, according to Dr. Koch. For example, if an intraoperative complication occurs while implanting a posterior chamber IOL, the surgeon might switch to an anterior chamber lens. He noted that an error can occur in two ways: 1) The surgeon simply makes an incorrect calculation by selecting a stronger power for the anterior chamber lens rather than a weaker power. 2) The surgeon does not have an actual calculation for the anterior chamber lens and does not correctly adjust the power. “For example, in eyes with axial myopia, the difference in power between the posterior and anterior chamber lens may be only 2 diopters. However, this difference can be as high as 4 diopters in patients who have short eyes,” Dr. Koch said.

    Andrew P. Schachat, MD, professor of ophthalmology, Wilmer Eye Institute, described another scenario in which IOL measurements for both eyes were in the chart. “The right eye was having surgery, but the surgeon looked at the printout and incorrectly selected the IOL measurement for the left eye. The policy on checking and double-checking during a time-out was not followed, and so the mistake was not caught.”

    Dr. Schachat noted that some eyes don’t have automated calculations, increasing the risk of human error. He cited one case in which there was a transposition error entered into the axial length. Amazingly, a meticulous technician had carefully remeasured, checked and rechecked, and got 26.3, 26.3 and 26.3 millimeters, but then very carefully entered 23.6 mm.

    “The surgeon should always query any pair of measurements for right vs. left eye wherein there is a difference of 0.3 mm or more and ask for more double-checking, or confirm any reason for such a difference. That was not done in this case,” Dr. Schachat said.

    Same-name snafu. Another potential pitfall surfaces when two patients with the same last name have their IOLs inadvertently switched.

    Richard L. Abbott, MD, professor, cornea and external diseases, University of California, San Francisco, described a case in which several patients were scheduled to have cataract surgery on the same morning. The circulating nurse brought all the implants into the room. There were two patients with the same last name. “For the first patient, the incorrect lens was given to the surgeon, even though the name was checked. Fortunately, the mistake was realized before the second patient with the same name was done, and this patient received the correct implant,” Dr. Abbott said.

    Like other physicians, Richard J. Mackool, MD, director, The Mackool Eye Institute, and senior attending surgeon, The New York Eye and Ear Infirmary, Astoria, N. Y., has seen several cases of wrong IOL placement over the years. In one case, the IOL was actually mislabeled by the manufacturer. Other cases were caused by surgeon or OR staff errors.

    He shared an unusual case. “One of the most interesting, and fortuitous, situations that I have ever seen was that of a colleague who implanted a 15-diopter IOL when a 25-diopter IOL was planned. He discovered his error several minutes after completing the procedure, and the patient was still in the OR.”

    “I was also in the OR and could see that he was very troubled. He told me what had happened, and I advised him to inform the patient and to change the implant at that time, but he was simply too distraught to act. I was concerned about him and called him at 9 a.m. the next day. When I asked how he was doing, he sounded perplexed, stating that he was fine. So I inquired about the status of the patient with the incorrect IOL, and he responded: ‘I saw her this morning and she’s 20/20 uncorrected. I guess the biometry was way off.’ ”

    After a Mistake: Amending, Then Mending

    What is the standard practice for informing the patient and remedying the situation after such a mistake is discovered? The experts agreed that the right thing is to inform the patient immediately and then discuss options to resolve the problem.

    “I think all large institutions have or are developing and enhancing their error disclosure polices. The Academy has ethics guidelines that speak to this, and I think we all know that the right thing to do is to disclose: Explain what happened, how you might be able to fix the error, and what steps you will take to avoid repeating the error,” Dr. Schachat said.

    If the wrong IOL has been implanted, the experts noted that the options for correcting postoperative refractive error would be to exchange the IOL with the correct one, to add a second (piggy-back) lens, or to perform corneal refractive surgery.

    Protocols for Prevention

    The best cure for OR mistakes, of course, is prevention. Our experts shared some strategies for minimizing the risk of errors in the surgical routine. Dr. Abbott emphasized that “every surgeon and ASC should have a protocol in place, and this should be followed without exception.” The following four protocols complement, rather than contradict, each other.

    Protocol Per the Academy

    Dr. Abbott suggested that a good starting point is the recommended policy of the Academy.

    All the experts stressed the importance of taking a “time-out” in the operating room before surgery during every case to double-check everything, as suggested by the Academy policy. Make sure that the patient identity is correct, that the medical record is in the OR, and that the A-scan and IOL calculation forms are correct, Dr. Abbott advised. “The lens should be matched to what has been requested in the medical record, and this should all be confirmed in the OR during the time-out period. When the lens is opened, the details of lens power, type of lens, etc., should be stated verbally by the scrub nurse to the surgeon,” he said.

    Verify, reconfirm, double-check. Dr. Koch described a similar protocol at his institution: “During the time-out in the operating room, we verify the implant power and the patient’s identity. We announce the patient’s identity and the procedure, and check the power of the implant by looking at the IOL calculation sheet. Finally, we reconfirm the IOL power by looking at the IOL box before it is opened. Our nurses pull the intraocular lenses the night before and place them with the surgical supplies for that given patient. In this way, there is no mixing of the lenses that will be used during the day,” he said.

    “The task of selecting the implant power can be delegated to a reliable assistant, but I prefer to verify the IOL selection. The surgeon is ultimately responsible,” Dr. Koch said.

    Protocol Per Dr. Chang

    Dr. Chang described the universal protocol for the 12 ophthalmologists using his ASC: “The circulating nurse, the scrub tech and the surgeon are all involved in confirming that the proper IOL is being implanted. The IOLs are ordered using a standardized fax sheet listing the day’s scheduled patients alongside their required IOL. If this sheet lists 10 names, then a copy of the form is cut into 10 strips, each containing one patient name and the matched IOL. This paper strip serves as an ID tag, and is taped to the IOL box that has been pulled for that patient. The surgeon checks all of these IOLs (with their paper ID tags) against his or her patient charts before the start of surgery. This would identify any clerical error made during ordering, or whether the wrong IOL model or power has been pulled. Before opening the IOL box during surgery, the circulating nurse announces the patient name written on the ID tag on the box, allowing the surgeon to verify that this matches the patient undergoing surgery,” he said.

    Dots and dilation. In addition to ensuring that the proper IOL is placed, Dr. Chang pointed out that several mechanisms work to ensure that the cataract surgery is done on the correct eye. “Dilating drops are always placed in the operative eye in the preoperative area, and the patient is usually alert and paying close attention as to whether the correct eye is being prepared. In addition, all ASCs have protocols for continually confirming the correct side for surgery. This starts with the consent form, and continues in the preoperative area with the dilating drops, and then the time-out in the operating room to confirm that the correct patient and eye are being prepared. Our ASC staff places a colored peel-off ‘dot’ on the patient’s forehead to designate the correct side. Finally, the surgeon sees the dilated pupil at the microscope to provide a final confirmation just before the incision,” Dr. Chang explained.

    Protocol Per Dr. Singer

    Dr. Singer maintains an Excel spreadsheet that lists all surgery cases and the IOL model/power for each patient. He selects all IOLs at least one week in advance and e-mails the selections for the following week’s cases to the operating room staff nurse, who maintains the IOL consignments and inventory.

    The day before surgery, Dr. Singer personally reviews all patient records and verifies the IOLs that he had previously selected. He makes any corrections or last-minute changes to the spreadsheet.

    Spreadsheets and stickers. On the morning of surgery, Dr. Singer’s surgical assistant prints out the spreadsheet segment for the day, brings it to the OR and confirms that the OR staff nurse pulled the correct IOLs for the day. Each patient is given a name label that is clearly visible, and the surgical eye is marked with a sticker on the patient’s forehead. Dr. Singer also brings a copy of the IOL spreadsheet segment for the day and tapes it to the operating microscope in a location that is visible from the surgical field. The IOL for each case is placed on his seat immediately before the case.

    After the patient is brought into the OR, Dr. Singer verifies the patient’s identity and the IOL model/power. “I tell the patient that I am verifying that we have their correct lens implant, and that they are who I think they are, and not an imposter! I then ask them which eye they expect to have done today, and verify that it matches the plan on the day’s spreadsheet,” he said. Then he hands the patient’s IOL (with a duplicate backup lens) to the OR nurse, who also verifies it against the IOL spreadsheet taped to the scope.

    Protocol Per Dr. MacKool

    Dr. Mackool’s institution has two special forms in the patient’s chart to minimize the possibility of human error in the process. On the first, they enter the patient’s name, the date, surgical eye and postoperative refractive target. The patient signs that form and brings it with them on the day of surgery. The second form lists the same information along with the type of lens and astigmatism plan, and has room to record any changes in a sequential fashion.

    Charting the changes. “If the plan changes, an additional entry containing all of the above data is made on the same page below the previous plan. This is important. Plans can and do change and these changes must be visible in a temporal fashion to ensure that the latest plan is carried out,” Dr. Mackool said.

    With regard to IOL selection in Dr. Mackool’s practice, two individuals independently verify that 1) the IOL calculations were done appropriately (i.e., the correct K readings and axial lengths were entered into the formula); 2) the plan on both of the above forms is the same; and 3) the IOL selected is consistent with the information entered on both of the forms described above.

    How Common Is Uncommon?

    All of the experts agreed that human errors in cataract surgery are uncommon, although it is difficult to establish exactly how often they occur. They agreed that minor mistakes might go unreported. “I presume that some of these cases do go unnoticed or unmentioned, particularly when the resulting refractive error is only slightly greater than anticipated,” Dr. Koch said.

    Fortunately, because of increased awareness and specific steps being taken to avoid these errors, Dr. Abbott thinks that this happens less commonly now.

    Dr. Schachat, however, noted that the reported incidence ironically may be up. “We are ascertaining errors more now because the environment is more favorable for error detection and reporting.” He also pointed out that patient expectations are higher, and so errors are more apparent. Patients are less likely to accept glasses or contacts to correct refractive error.

    Dr. Koch noted that “wrong IOL placement is a rare but potentially devastating complication, particularly if correction of the error results in a surgical complication that leads to loss of vision. The psychological damage to the patient can be severe.”

    Is one too many? “It happens. It is avoidable. The goal is 100 percent correct; not 99 percent,” Dr. Schachat said. “We are all under tremendous pressures, both to achieve perfection and to do it faster than we did in the past. Common sense dictates that if you slow down a little bit, there is more of a chance to detect errors before they happen. A time-out and a careful system with checking and double-checking by more than one person are key aspects of the Academy-recommended approach. This should help us to reach that 100-percent goal.”

    Color Us Different

    The proliferation of so many new IOL options, such as multifocal and aspheric optics, has increased the odds of making mistakes, Dr. Chang noted. Although a company may use different model numbers to differentiate its monofocal and multifocal acrylic IOLs, the boxes themselves may not be remarkably distinct. He called on lens manufacturers to help surgeons and ASC personnel avoid confusion by using different colors on their IOL boxes.

    Meet the Experts

    Richard L. Abbott, MD Professor, cornea and external diseases, University of California, San Francisco, and secretary for the Academy’s Quality of Care and Knowledge Base Development.

    David F. Chang, MD Clinical professor of ophthalmology, University of California, San Francisco, and in private practice, Los Altos, Calif.

    Douglas D. Koch, MD Professor of ophthalmology, Baylor College of Medicine, Houston.

    Richard J Mackool, MD Director, The Mackool Eye Institute, and senior attending surgeon, The New York Eye and Ear Infirmary, Astoria, N.Y.

    Andrew P. Schachat, MD Professor of ophthalmology and vice chair for safety and quality, Wilmer Eye Institute, Baltimore, Md., and editor-in-chief, Ophthalmology.

    Jack A. Singer, MD President, Singer Eye Center, Randolph, Vt.