Update on Colonoscopy Preparation, Premedication and Sedation

Jeffrey R Lewis; Lawrence B Cohen

Expert Rev Gastroenterol Hepatol. 2013;7(1):77-87.

Abstract and Introduction

Abstract

The advent of optical colonoscopy has enabled gastroenterologists to visualize the colonic mucosa. This procedure has since become the cornerstone of colon cancer screening programs. Clinicians and scientists have made great strides to fine-tune the technical aspects of this procedure and have also made important advances that allow for a more effective and safer colonoscopy. This article focuses on current research and expert opinion regarding colonoscopy preparation, premedication and sedation.

Introduction

Colonoscopy quality has improved during the past decade due to advances in image technology, bowel preparation and sedation techniques. Nonetheless, opportunities for further improvement in outcome measures of colonoscopy remain. For example, studies from diverse settings have shown that colonoscopy is less effective in preventing proximal compared with distal cancers. Improved detection of proximal adenomas and serrated lesions would likely help to bridge this difference in outcome between proximal and distal cancers. This article presents a state-of-the-art review of bowel preparation, premedication and sedation and describes recent studies and how these findings may one day further enhance our practice of colonoscopy.

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Table 1. Ottawa Bowel Preparation Scale.
Quality of preparation	Score
Assessment of right, mid-colon and left colon
No liquid	0
Minimal liquid, no suctioning required	1
Small particles, suctioning required	2
Semi-solid, wash and suction	3
Solid stool, not all washable	4
Overall colon assessment
Amount of fluid present	0–2

The scale rates three sections of the colon, right (cecum and ascending colon), mid-colon (transverse and descending) and rectosigmoid, on a five-point scale (0–4).
Total score (0–14) is obtained by adding the scores for individual evaluation of right, mid-colon and left colon with the score of overall fluid.
Modified from [3].

Table 2. Approach to antiplatelet therapy in the periendoscopic period.
Thrombotic risk	Endoscopy with low bleeding risk	Endoscopy with high bleeding risk
*Low^†*
Coronary DES placed >12 months previously	Continue APA therapy	Stop ASA 5 days prior to EUS-FNA of cysts, EMR and ESD, ampullary resection and endoscopic sphincterotomy with large-balloon papillary dilation for biliary stone extraction
Bare-metal coronary stent placed >6 weeks previously without risk factors^‡		In patients taking a thienopyridine alone, it is recommended to substitute aspirin^§
Stroke without cardiac failure >6 weeks previously
*High^†*
Coronary DES placed ≤12 months previously	Continue dual APA therapy
Bare-metal coronary stent placed ≤6 weeks previously or >6 weeks with associated risk factors^‡		Delay endoscopy and/or consult a cardiologist to discuss temporary cessation of thienopyridine:Clopidogrel, 5 daysPrasugrel, 7 days
Stroke ≤6 weeks previously		ASA should be continued in all cases

^†Patients with a low thrombotic risk receive a single antiplatelet agent; those with a high thrombotic risk receive two antiplatelet agents.
^‡Risk factors: diabetes, renal failure, cancer, chronic heart failure, complex coronary artery stenosis or history of coronary stent thrombosis.
^§Thienopyridines should be stopped (clopidogrel for 5 days and prasugrel for 7 days) prior to procedure and aspirin substituted. Thienopyridines will be resumed shortly after the procedure if aspirin is inadequate for long-term prevention.
APA: Antiplatelet agent; DES: Drug-eluting stent; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection; EUS-FNA: Endoscopic ultrasonography-guided fine.needle aspiration.
Reprinted with permission from [26].

Table 3. Bleeding risk associated with endoscopic procedures.
Bleeding risk	Procedure	Continue aspirin	Continue thienopyridine
Low	EGD and colonoscopy ± biopsy	Yes	Yes
	EUS without FNA	Yes	Yes
	Colonic polypectomy <1 cm	Yes	No^†
	Dilation of digestive stenosis	Yes	No
	EUS-FNA of solid masses	Yes	No
	Digestive stenting	Yes	No
	ERCP with stent placement or papillary balloon dilation without endoscopic sphincterotomy	Yes	Yes
	Argon plasma coagulation	Yes	No^‡
High	EMR, ESD and ampullary resection	No	No
	Endoscopic sphincterotomy	Yes	No
	Endoscopic sphincterotomy + large balloon papillary dilation	No	No
	Colonic polypectomy >1 cm	Yes	No^†
	EUS-FNA of cystic lesions	No	No
	Percutaneous endoscopic gastrostomy	Yes	NA
	Esophageal variceal band ligation	Yes	No

^†Bleeding may be prevented by placing a detachable loop ligating device or utilizing submucosal injection. The resection of small polyps (<1 cm) is probably safe in patients taking clopidogrel (not prasugrel) with such preventive measures. Insufficient data are available regarding prophylactic endoclip placement.
^‡Argon plasma coagulation can be safely used to treat angiodysplasias without holding thienopyridines. EGD: Esophagogastroduodenoscopy; EMR: Endoscopic mucosal resection; ERCP: Endoscopic retrograde cholangiopancreatography; ESD: Endoscopic submucosal dissection; EUS-FNA: Endoscopic ultrasonography-guided fine needle aspiration; NA: Not applicable.
Reprinted with permission from [26].