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Comfortable, lightly sedated colonoscopyReferring to Nass KJ et al. p. 619–626
There are three components to a successful colonoscopy: intubation to the cecum, lesion recognition, and lesion excision. Each of these can be assessed using competencies and/or performance measures. Competency assessment is used to identify areas in need of improvement, or to determine competency to practice independently (such as a driving test). Performance measures determine the consequence of applying the competencies: does the driver get to her destination safely? There are other important nonprocedural measures to consider in a colonoscopy service such as efficiency, costs, consent, aftercare, patient satisfaction, etc. .
“But why should patients in similar countries have different expectations/demands with regard to sedation? Are patients in countries using more sedation likely to be less stoic, or is their experience of colonoscopy making them more demanding?”
In recent years, the adenoma detection rate (ADR) has trumped all other performance measures because it is a good proxy for interval cancer . But, ADR is not the Holy Grail: in a review of > 100 cases of postcolonoscopy colorectal cancer, service organizational issues were just as important as procedural quality . Unfortunately, there has been an emphasis on ADR at the expense of measures of intubation and lesion excision, and the nonprocedural aspects of a service. Furthermore, there has been a tendency to use ADR as a determinant of the worth of other measures, downplaying their individual merit.
Intubation to the cecum, even with modern equipment, can be very tricky and sometimes painful. In most jurisdictions, sedation is used to improve the patient experience. Clearly, patient comfort, sedation, and completion to the cecum are linked, and in 2018 we reported a new measure of intubation combining all three, called the Performance Indicator of Colonic Intubation (PICI) . PICI is achieved if the cecum is intubated, ≤ 2 mg midazolam is used, and the patient is comfortable. PICI was found to be more likely to reveal differences in performance in relation to volume, experience, training, type of patient, professional group, and unit accreditation than its individual components. On this basis, it was argued that PICI gave a richer, more subtle picture of colonic intubation than the cecal intubation rate alone.
Our principal recommendation was for PICI to be used at a local level to identify improvement opportunities and we illustrated this potential with data from a single service. It was suggested PICI might be used for benchmarking, but only if assessment of comfort could be standardized.
In this issue of Endoscopy, Nass et al. investigated the PICI for colonoscopies performed in the Dutch National Colorectal Cancer Screening Programme . The headline conclusion is that midazolam dosage constrains the use of PICI as a benchmark. Achieving PICI was associated with a small but statistically significant increase in ADR. The PICI was calculated for different midazolam thresholds: 46.1 % for 2.5 mg and 88.9 % for 5 mg of midazolam. The challenges of assessing comfort consistently were not discussed, there was no discussion of using PICI at a local level for enhancing performance, and, disappointingly, no attempt to confirm or refute our key finding that PICI is a more discerning indicator of variation than its individual components.
Dose of midazolam was considered a constraint because of “different national flavors” in sedation practice, both in the variable use of midazolam and use of propofol. Reasons for those differences, whether they matter, and what effect a change in sedation practice would have on levels of comfort and cecal intubation, were not discussed. These are important questions that are often ignored in studies of sedation practice; the relationship of sedation to ADR and harm are more usual.
Endoscopists are used to giving a certain amount, or type, of sedation and see no reason to change, and certainly not to reduce it. Therefore, differences could be attributed to habit. However, habit would not explain the increasing popularity of propofol. Patient expectations and/or demand, and faster recovery rates when using propofol are other reasons given for using more or different sedation. But why should patients in similar countries have different expectations/demands? Are patients in countries using more sedation likely to be less stoic, or is their experience of colonoscopy making them more demanding?
Patients would have more interest in measures of intubation than endoscopists if they knew how much variation there was, and what was achievable. An informed patient, such as an endoscopy nurse, will be more discerning. Consider a retired endoscopy nurse with a choice of three colonoscopists (who she has not worked with) who have the same ADR: two using conscious sedation, one with high PICI and one with low PICI; the other using propofol. Of the two using conscious sedation she would choose the colonoscopist with a high PICI every time. The option of propofol is more difficult because the nurse has witnessed substantial variation in the way the colon is intubated, even with propofol, but has no data to make the choice. Of course, the nurse will get around the problem by asking her colleagues who they would recommend. Patients do not have this option and have no data to help them make an informed choice, unless the person using propofol has previously shown they are capable of achieving a high PICI.
A few milligrams of midazolam are unlikely to substantially increase the risk of a colonoscopy, but a heavily sedated patient can be difficult to turn and takes more time to recover. Turning the patient can increase the ADR  and sometimes turning is essential to optimize access for polypectomy. So, being able to turn the patient easily is a good reason to use less sedation, providing the patient is comfortable and the cecum can be reached.
In conclusion, PICI is a patient-centered measure of colonic intubation. It is most useful at a local level to identify variation in colonic intubation in order to target performance improvement. Its use as a benchmark is constrained by objective measurement of comfort, less so by sedation. If higher doses of sedation are used routinely there is no reason why different midazolam thresholds could not be used, or simply reported on. Essentially this is what Nass et al. have done using 2.5 mg and 5 mg thresholds (PICI-2.5 and PICI-5). The authors seemed pleased that 88.9 % had achieved the measure with PICI-5. This misses the point: if everyone achieves the measure most of the time, it is difficult to see who needs to improve. Much better to have a measure achieved some of the time (PICI-2.5) when differences rapidly become apparent. If we truly aspire to excellence, while recognizing every single one of us can always improve, a lower threshold (PICI-2.5) makes sense, even in the Netherlands.
26 May 2021 (online)
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