Patient Comfort During Colonoscopy

Authors

Study design

Total procedures (% sedated procedures)

Difference in CIR

Difference in cecal intubation time

Difference in ADR

Bannert et al. [5]

Retrospective

52,506 (86%)

Yes (1.2%)

Radaelli et al. [6]

Retrospective

12,835 (55%)

Yes (8%)

PDR higher with sedation

Crispin et al. [7]

Retrospective

236,087 (97%)

Yes

Paggi et al. [8]

Prospective

964 (44%)

Yes (16%)

Petrini [9]

Prospective

2090 (72%)

Aljebreen [10]

Prospective

403 (67%)

Two groups have reported prospectively collected data on unsedated colonoscopy in their practices. Paggi et al. reported a 56% acceptance rate of unsedated colonoscopy [8]. The CIR was 82% and increased to 97% when on-demand sedation was administered. Adenoma detection rates were similar for sedated vs. unsedated patients. They found that patients who had an absent/low level of self-reported pre-procedure anxiety, no concern about the exam, and first-time procedure were all associated with acceptance of an unsedated procedure. Absence of pre-procedure anxiety was associated with completion of the procedure without medication. Petrini et al. described their experience with unsedated colonoscopy: [9] 28% of 2091 patients elected to start the procedure without sedation and of those 81% completed it without sedation. Cecal intubation rate and time to cecum was the same for patients sedated at the start of the procedure and those who were unsedated throughout the procedure.

Patients should be informed of the option of unsedated colonoscopy. Physicians who use this technique must recognize that it requires an increased amount of communication with the patient and more patience in performance of the procedure. While patient selection is vital to the successful use of this technique, provisions for sedation should be immediately available for those who initially elect to forgo sedation but during the procedure decide they need sedation.

Propofol Versus Benzodiazepine +/− Opioid

The American Society of Anesthesiologists has described different levels of sedation based on patient responsiveness, ability to protect the airway, spontaneous ventilation, and cardiovascular function (Table 5.2) [11]. For endoscopic procedures, propof ol is frequently equated with deep sedation and the combination of a benzodiazepine with an opioid (B/O) is equated with minimal/moderate sedation; however, the agent used and the level of sedation are two separate issues—in other words, moderate or deep sedation can be achieved with either agent. For most patients either sedation strategy will provide adequate sedation. Anecdotally, the author’s impression is that it seems that there are more patients on anxiolytics, narcotics, and antidepressants than previously and these patients require higher doses of the traditional B/O combination.

Table 5.2

Levels of sedation/analgesia

	Minimal	Moderate	Deep	General anesthesia
Responsiveness	Normal	Purposeful	Purposeful to repeated painful stimuli	Unarousable
Airway	Unaffected	No intervention required	Intervention may be required	Intervention often required
Spontaneous ventilation	Unaffected	Adequate	May be inadequate	Frequently inadequate
Cardiovascular function	Unaffected	Usually maintained	Usually maintained	May be impaired

Developed by the American Society of Anesthesiologists; approved by the ASA House of Delegates October 13, 1999, last amended 2014. www.asahq.org—Standards and guidelines, 10.15.14

The advantages and disadvantages of propofo l are outlined in Table 5.3. A meta-analysis confirmed the decreased recovery time and time to discharge, as well as the improved patient satisfaction with propofol over B/O [12]. There were no differences in complication rates between the two types of sedation. The authors note that a limitation of this study is that the vast majority of patients were “generally healthy.”

Table 5.3

A comparison of some advantages and disadvantages of propofol for colonoscopy

Advantages	Disadvantages
Quick and reliable onset of action	Increased cost
Recovery and time to discharge	Increase personnel
Rapid return to baseline function	Difficulty with positional changes
Patient satisfaction	Increased coughing
Physician satisfaction	Lack of reversal agent
Efficacy in difficult to sedate patients

A review of SEER data compared complications in over 165,000 colonoscopies performed with anesthesia assistance vs. those without—the presumption being that those with anesthesia assistance are almost all propofol cases [13]. The authors found overall complications were higher in the anesthesia-assisted group (0.22% vs. 0.16%) as was the rate of aspiration (0.14% vs. 0.10%). Perforations and splenic injuries were similar between the two populations. The authors conclude that depth of sedation may be a risk factor for complications.

I would add (based on personal experience of 10 years experience of B/O sedation followed by 3 years of sedation with propofol ) my experience favors propofol as a quicker more reliable form of sedation for colonoscopy . Patients do need more airway attention and I have abandoned routinely moving patients from left lateral to supine on achieving cecal intubation. Since patients who are under deep sedation are generally unable to help in changing positions, I now leave larger patients and those with known sleep apnea in the left lateral position. A small percentage of patients can develop a prolonged cough that is felt to represent micro-aspiration [14]. In addition to the risk of aspiration pneumonia, this cough can cause technical difficulty with examination of the mucosal surface and polypectomy.

Ulmer et al. reported on a randomized trial of nurse administer propofol vs. midazolam/fentanyl [15]. They found that patients who received propofol were sedated faster, to a deeper level of sedation, and were discharged home quicker. They also scored better on a series of post-procedure tests of learning, memory, working memory span, and mental speed.

Several models exist for how sedation is administered for endoscopic procedures (Table 5.4). Barriers to widespread use of propofol include an increase in cost in large part because of the increased use of anesthesia services. There is an FDA/package insert warning with propofol stating it should be “administered only by persons trained in the administration of general anesthesia and not involved in the conduct of the surgical/diagnostic procedure.” Other factors which limit endoscopist administered or directed use of propofol include state nursing board regulations, hospital policies/credentialing, lack of familiarity with the drug, and cost/reimbursement issues. Despite these issues, there is ample evidence that non-anesthesiologist-administered propofol can be safely accomplished.

Table 5.4

Common sedation models for colonoscopy^a

Provider role	Targeted level of sedation	Typical agents	Comments
Endoscopist administered	Light to moderate	Benzodiazepine +/− opioid	Nursing personnel must still monitor patient
Endoscopist directed	Light to moderate	Benzodiazepine +/− opioid
Endoscopist directed—registered nurse administered	Moderate to deep	Propofol	Most institutions require special training/credentialing
Nurse anesthetist administered	Moderate to deep	Propofol	Supervised by anesthesiologist or endoscopist
Anesthesiologist administered	Moderate to deep	Propofol	Most commonly used in higher risk patients

^aCombinations and modification of these strategies can be made on individual basis. For example—patients being sedated with a benzodiazepine and opioid may experience enough discomfort that deep sedation is required and which can be produced with those agents

Because colonoscopy is performed so frequently it is a prime target for cost reform and because the socioeconomic landscape is constantly changing it is difficult to know what impact reimbursement will ultimately have on the future use of propofol . The current model of anesthesiologist directed or administered propofol changes the cost-effectiveness of colonoscopy as a screening exam—the question that remains is what the magnitude of that change will be. An additional result of this model is that the physicians and nursing staff lose the skill set of conscious sedation making them dependent on anesthesia services to accomplish their procedures.

Opioids Alone

Fentanyl, remifentanil, and alfentanil have all been described for single agent use for colonoscopy. The benefit of this approach is that less sedation is achieved and therefore the risk of complications from sedation is avoided. The data available are from a small number of trials. In one, patients receiving fentanyl had lower pain scores and shorter times to cecal intubation than patients who were given midazolam [16]. The midazolam group experienced a decrease in O₂ sat in 35% of patients compared to none with fentanyl.

Remifentanil may shorten recovery times compared to B/O with less respiratory depression. Side effects and the need for administration by a separate trained person have limited its use for colonoscopy [17]. Only one small trial of alfentanil in colonoscopy has been performed [18]. This study showed fewer patients given alfentanil alone were less likely to require supplemental oxygen compared to those administered alfentanil with midazolam. No other differences were noted.

CO₂ Insufflation Colonoscopy

Several procedural adjuncts have been described to decrease pain, reduce the amount of sedation required, or enable/facilitate performance of unsedated colonoscopy. The two techniques that seem to have garnered the most attention are CO₂ insufflation and water-aided colonoscopy. There is data for each of these individually and more recent studies have compared them head-to-head or used together.

CO₂ insufflation is believed to decrease pain from colonoscopy due to the rapid absorption of this gas relative to air. This technique requires a CO₂ regulator and a source of the gas—gas line or refillable cylinders. Wu and Hu performed a systematic review and meta-analysis of nine randomized trials with 1577 patients comparing CO₂ vs. air insufflation [19]. Procedural sedation included unsedated patients, B/O, and propofol . CIR and cecal intubation times were similar for the two groups. The methodology in this study involved comparing patient with any pain (visual analog score [VAS] > 0) to those with no pain. Using this criteria, they found a benefit with regard to pain during the procedure, and at 1, 6, and 24 hrs post-procedure. There were no differences in complications and end-tidal CO₂ levels were similar during and after the procedure. The authors come to the over-reaching conclusion that these findings “warrant wide clinical use.”

There has been no report that demonstrated an increased complication rate for CO₂ colonoscopy . The additional cost includes the gas regulator that is connected to the colonoscope and the cost of CO₂. The benefits for routine screening colonoscopy appear to be minimal and it does not appear to increase the ability to perform unsedated colonoscopy. However, for patient with suspected obstruction or intestinal distention pre-procedure, CO₂ is an excellent option. It may also have benefit in cases in which advanced polyp resection techniques (endoscopic mucosal resection, endoscopic submucosal dissection) are used as well as intraoperative colonoscopy.

Water-Aided Colonoscopy

Two types of water-aided colonoscopy have been described [20]. The first is water immersion. In this technique, water is infused during insertion of the colonoscope and is removed during scope withdrawal. Use of air insufflation is used as needed to provide adequate visualization. After cecal/ileal intubation, the water is removed and gas insufflation is used for withdrawal, mucosal inspection, and any biopsies or polypectomies that need to be performed. Water exchange is a modification of water immersion that involves complete exclusion of air, thus avoiding the lengthening of the colon caused by insufflated gas moving quickly into the cecum.

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