Informed consent for therapeutic colonoscopy is obtained in accordance with the informed consent for general colonoscopy . Informed consent is obtained according to hospital or individual center policy.

Informed consent includes assessment of the competence of the individual to process information, disclosure of appropriate information necessary to allow an informed decision, and ensuring the plan chosen by the patient is voluntary. The process involves mutual communication and decision-making , not merely the request for a signature on a standardized form that lists complications of a procedure. The four elements of risk that physicians need to consider in providing informed consent are: (1) nature of the risk; (2) magnitude of the risk (seriousness); (3) probability that the risk may occur; (4) imminence of the risk (i.e. post procedure or decades later).

About informed consent for therapeutic colonoscopy, consider information an average patient may want (Table 1.2). Should one mention the possibility of death as a result of the procedure? One study from England reported that a survey of barristers (the English equivalent of plaintiff’s attorneys) indicated that serious risks should be mentioned even if as rare as one in a million [2]. Although it is generally legally safer to mention more risks (including very rare risks), there is a potential cost in unnecessarily frightening patients away from beneficial procedures by not adequately conveying the rarity of such an event.

In process of consent, the colonoscopist must ensure that the patient is competent to understand the information disclosed. Note that the medical literature contains information indicating that ordinarily competent older patients may be temporarily unable to adequately comprehend information when hospitalized with a serious illness. Having a family member present may be useful to ensure adequate consent or at least reduce the likelihood of successful consent challenge later. Informational materials may be given to the patient to facilitate understanding of the procedure. Appropriate institutional forms should be signed and witnessed, and a statement written or dictated as part of the colonoscopy note indicating that informed consent has been obtained. It is best if the witness to consent is a family member or friend, since this implies that the witness believes the patient capable of consent, and is also there to help in the process. If a member of staff witnesses the consent, it is best if this is not the person obtaining the consent or helping perform the procedure. If an issue comes to trial and those in the procedure room are named as defendants, their testimony witnessing the adequacy of consent may appear biased.

The standard core elements of informed consent (Table 1.3) include the nature and character of the procedure (preferably in nontechnical terms), the material risks of the procedure, the likely benefits, and the potential alternatives (including no treatment). Most consent forms will also include the patient’s name, date and time of consent, disclaimer of guarantee of success, identification of staff who will perform the procedure, consent to allow the physician to modify the procedure for unforeseen circumstances, an acknowledgment that the patient has been given the opportunity to ask questions which have been answered, consent to disposal of removed organs, and, with new privacy concerns and regulations, consent for transmission of the results to appropriate parties.

In colonoscopies, the exceptions to informed consents could be applied with caution (Table 1.4). In an emergency situation, a healthcare provider may treat the patient without obtaining consent; consent is presumed, or “implied” in legal parlance. The definition of emergency may vary in different jurisdictions, but the principles of imminent harm by failure of prompt treatment can be applied. This issue is less likely to arise with colonoscopy. Further, attempting even a limited consent with a conscious patient is worthwhile if it will not unduly delay emergency treatment.

Patients are able to waive their right to informed consent. However, they must know they have the right to information necessary to make an informed decision. Thus when a colonoscopy patient says “You’re the doctor, you decide what is best,” the careful doctor may accept that responsibility but will first inform the patient of the right to information and decision-making.

Therapeutic privilege allows physicians to withhold information they generally must disclose, based upon the physician’s perception that disclosure will be harmful to the patient. However, this is a disfavored exception; there is concern that it may be used as an excuse for not informing patients. Unless there is clear and convincing evidence of psychologic fragility, it would be best to ignore this exception.

The ethical and legal requirement to obtain informed consent prior to performing colonoscopy derives from the concept of personal (patient) autonomy. The competent patient, after receiving appropriate disclosure of the material risks of the procedure, understanding those risks, the benefits, and the alternative approaches, makes a voluntary and uncoerced informed decision to proceed. This is a basic ethical obligation in the practice of medicine. It should be a communication tool that cements the provider–patient relationship . It functions as a risk-management tool, transferring known standard procedural risks to the patient who has understood and accepted the premise that even competently performed colonoscopy has risks. The procedural elements involved in obtaining consent include a discussion of material risks, acknowledge of who gives and obtains consent, the scope of consent, exceptions to consent, witnessing and documentation of consent, and the use of educational materials and consent forms.

Consent is a mutual process, which occurs after appropriate disclosure, with time for answering questions, in an uncoerced process. In open-access colonoscopy , the patient has not met the colonoscopist prior to the decision to proceed with colonoscopy, prior to having undergone preparation for the procedure, or in some cases prior to arriving in the procedure room with an intravenous line in place.

As the elderly population grows, more patients receiving medications such as aspirin, anticoagulants, and nonsteroidal anti-inflammatory drugs (NSAIDs), are being referred to endoscopists for therapeutic colonoscopy. For patient’s convenience, polypectomy is often performed as soon as a polyp is detected to avoid another bowel preparation. Therefore, if the patient’s concurrent medication increases the risk of bleeding after polypectomy, this should be considered before the colonoscopy. The patients in whom discontinuation of the antithrombotic agent poses only a low risk may stop their medication during the periendoscopic period [3–5]. However, a careful evaluation is needed in cases when discontinuation of the antithrombotic agent is associated with a high risk of adverse effects [3–5]. A previous study showed that the use of aspirin or clopidogrel alone was not related to higher rates of postpolypectomy bleeding [6].

The management of the medications needs to be considered during the periendoscopic period in patients receiving anticoagulant agents such as warfarin, unfractionated heparin (UFH), and low molecular weight heparin (LMWH), and antiplatelet agents such as aspirin, NSAIDs, dipyridamole, thienopyridines (clopidogrel and ticlopidine), and glycoprotein II/IIIa (GP II/IIIa) inhibitors (tirofiban, abciximab, and eptifibatide) [3–5]. The management is based on the assessment of the procedure-related bleeding risk and potential thromboembolic risks related to the discontinuation of the medication [3–5].

Aspirin and/or NSAIDs are recommended to be continued during all endoscopic procedures, and clinicians may discontinue aspirin and/or NSAIDs for 5–7 days before the high-risk procedures such as polypectomy and endoscopic submucosal dissection [3–5]. In patients with a vascular stent or acute coronary syndrome, clopidogrel or ticlopidine may be withheld for 7–10 days before the endoscopy, provided that a minimum recommended period after the corresponding treatment has passed, and aspirin could be continued [3–5]. If clopidogrel or ticlopidine is used for other indications, these medications could be continued for low-risk procedures such as diagnostic colonoscopy including biopsy. However, they need to be discontinued for 7–10 days before high-risk procedures. Anticoagulant (warfarin ) discontinuation is recommended in patients with a low risk of thromboembolic events [3–5] (Table 1.5).

Continuation of anticoagulation by switching to LM-WH or UFH is recommended in the periendoscopic period in patients with higher risks of thromboembolic complications [3–5] (Table 1.5). In patients with a high risk of thromboembolic events, UFH or LMWH needs to be restarted as soon as possible, and warfarin can be restarted on the day of the procedure without a significant danger of bleeding [3–5]. In patients with a low risk of thromboembolic events, warfarin may be restarted on the evening after the endoscopy without a high risk of postprocedural bleeding [5].

In patients with acute GI bleeding receiving an anticoagulant or antiplatelet agent, this medication is recommended to be withheld until hemostasis is achieved [5].

The purposes of procedure-related sedation include safe and effective management of pain and anxiety in addition to acquirement of a proper degree of memory loss and decreased awareness. Currently, there is no standard regimen regarding sedation in GI endoscopy [7]. The choice of sedation may differ depending on the endoscopist’s preferences and the type of planned procedure. In special conditions such as obesity, pregnancy, advanced age, and chronic lung, liver or renal disease, special considerations and precautions are required regarding the dose adjustment and choice of sedative drugs [7, 8].

Midazolam is considered the benzodiazepine of choice as it provides a shorter duration of action with a better pharmacokinetic profile than diazepam [7, 8]. Pethidine and fentanyl are the most popular [7, 8]. Reversal drugs for endoscopic sedative drugs consist of flumazenil and naloxone [8] Flumazenil , a benzodiazepine antagonist, reverses the respiratory and sedative effects of benzodiazepine [8]. Naloxone , a pure mu-opioid antagonist, reverses both the respiratory and analgesic effects of opioids [7, 8].

Unsedated endoscopic procedures are recommended for elderly patients or patients with the risk of cardiopulmonary dysfunction.

The use of propofol for sedation during diagnostic and therapeutic procedures is increasing as it enhances the quality of upper GI endoscopy by increasing the patient’s acceptance of the procedure and the diagnostic accuracy [9]. In addition, it has satisfactory sedative, hypnotic, antiemetic, and amnesic properties, as well as a rapid onset of action and a short recovery profile [7, 8]. Its use is preferred in patients with advanced liver disease because of its short biologic half-life resulting in a low risk of hepatic encephalopathy [8]. With regard to side effects, propofol may induce cardiopulmonary events. It can cause a dose-dependent decrease in cardiac contractility leading to a decrease in cardiac output, systemic vascular resistance, and arterial pressure [7, 8]. In addition, it may be associated with serious adverse events such as respiratory depression, airway obstruction, and death [7, 8]. Unfortunately, there is no pharmacological antagonist for this compound [7, 8]. In a prolonged and potentially uncomfortable endoscopic procedure, intravenous midazolam along with propofol for sedation has been reported to be more effective than intravenous midazolam alone, without differences in the safety [10].

Meperidine (category B) followed by small doses of midazolam (category D) as needed is recommended for moderate sedation in endoscopic procedures during pregnancy [11]. Breastfeeding may be continued after fentanyl (category C) or propofol (category B) administration in lactating patients after sufficient recovery from general anesthesia. Infants should not be breastfed for at least 4 h after midazolam is administered to the mother [11].

Patient’s age, inpatient status, higher American Society of Anesthesia grade (Table 1.6), routine use of oxygen, and trainee participation were associated with a higher incidence of unplanned cardiopulmonary events during GI endoscopy under conscious sedation [12].

Although dietary modifications alone are not sufficient for preparation for colonoscopy, they have proven to be effective when conducted together with mechanical cleansing [13]. For dietary regimens, clear liquids and low-residue diets are recommended for 1–4 days before colonoscopy [13, 14]. Patients are allowed to have water, clear soup, clear fruit juice without pulp, coffee or tea without milk, and sport drinks on the clear liquid diet [14]. In addition, patients may have white rice, white rice cakes, refined noodles or pasta, vegetable juices, grapes without skin and seeds, peaches without skins and seeds, watermelon without seeds, well-cooked potatoes without skin, tender meat, fish, chicken, and eggs on the low-residue diet [14]. Patients are forbidden to have high-fiber foods such as brown rice, whole grains, raw and dried fruits, seeds, nuts, and multigrain bread [14]. Prolonged dietary restrictions may also be an important factor for better colon preparation, but they could lead to lower compliance [13]. Nevertheless, prolonged fiber restriction with liquid diet needs to be suggested in cases of severe constipation [15]. Furthermore, a study suggested that the fiber-free diet is more effective than the clear liquid diet if it is combined with the use of polyethylene glycol (PEG) electrolyte solution on the day before colonoscopy [16].

The ideal preparation for colonoscopy needs to satisfy the requirement of emptying the colon of all solid or liquid materials in a rapid fashion with no gross or histological changes in the colonic mucosa. Additionally, shifts in fluids or electrolytes, patient discomfort, and cost should be kept to the minimum [17].

PEG-electrolyte lavage solution is the most frequently prescribed bowel-cleansing agent. As it is a nonabsorbable solution, it passes through the bowel without net absorption or secretion, and significant fluid or electrolyte shifts do not occur [13]. Therefore, PEG is considered safer than stimulant laxative/sodium phosphate (NaP) in patients with fluid or electrolyte imbalance [13]. It is preferred in patients with renal insufficiency, congestive heart failure, or liver failure [13] The drawbacks of this agent are that it should be diluted in a large volume of water (up to 4 L) to reach the desired cathartic effect and it’s un-palatable taste despite flavoring, which leads to poor compliance [13]. Sulfate-free PEG (SF-PEG) was developed to improve the taste and smell of the PEG solution by decreasing the potassium concentration, increasing the chloride concentration, and eliminating sodium sulfate [13]. SF-PEG is considered to be comparable to PEG in safety, effectiveness, and tolerance, but it still requires consumption of 4 L of the diluted agent [13]. Aqueous NaP is no longer prescribed, as it may cause significant fluid and electrolyte shifts resulting in renal failure; however, NaP tablets are still available. Adjunctive agents are used to enhance the cleansing efficacy of bowel preparation conducted by the main purgative regimens such as PEG, as well as to reduce the volume of fluid that needs to be taken to achieve a cathartic effect [18]. Ascorbic acid , which is not completely absorbed and remains in the colonic lumen, exerts an osmotic effect and is used with a smaller quantity of PEG [19, 20]. Low-volume PEG solutions with ascorbic acid have been reported to be comparable to high-volume PEG solutions in efficacy and tolerability by the patients [19, 20]. Magnesium salts that show a synergic effect through their osmogenic properties are often used with picosulfate, a prodrug that is metabolized to a peristalsis-enhancing stimulant within the bowel lumen [21]. The regimen with sodium picosulfate and magnesium citrate is gradually accepted as a major bowel-cleansing regimen based on its efficacy and safety profiles [22]. Other adjuncts such as bisacodyl, senna, and metoclopramide have been reported to have the advantage of reducing the volume of the solution required for bowel cleansing; however, their exact efficacies and safety profiles remain to be established [13, 18, 23].