Description of the condition
Colonoscopy is increasingly used for the detection and surveillance of colorectal conditions. It is particularly important in the secondary prevention of colorectal cancer by detecting polyps which are thought to undergo malignant change with time if left untreated (Morson 1971). It is important for the entire colorectum to be visualised from the anal margin to the caecal pole in order to reduce the likelihood of missed polyps. The intrinsic nature of the bowel with its tortuous course and differences in anatomical mobility can make colonoscopy difficult for both patient and practitioner. It can be an uncomfortable procedure for patients as the endoscope and gas insufflation stretch the bowel wall and put tension on the colonic mesentery (Hull 1994; Takahashi 2005). Patient discomfort is more pronounced during insertion of the colonoscope due to the formation of loops within the mobile segments of the colon, usually the sigmoid and transverse segments (Cotton 2008; Shah 2002). Techniques that would aid the passage of the colonoscope may improve patient comfort, speed up the intubation process and improve caecal intubation rates.
Description of the intervention
Hyoscine-N-butylbromide (scopolamine, Buscopan® (Boehringer Ingelheim, Germany)), is an antispasmodic drug derived from the plant genus Duboisia first licensed in the 1950s. It is a rapid-acting cholinergic muscarinic antagonist. Its duration of action when administered intravenously is about 20 minutes and its common side effects include tachycardia, blurred vision and xerostomia. It is used variably by colonoscopists and radiologists to reduce bowel spasm during colonoscopy and colonography (Elphick 2009; Goei 2000; Yoshikawa 2006).
How the intervention might work
The role of intravenous hyoscine-N-butylbromide (IVH) in colonoscopy is poorly defined and we aim to examine the literature on the subject with the aim of defining its usefulness with regards to expediting colonoscope passage and improving the detection of polyps. Investigators have suggested that IVH relaxes colonic smooth muscle hence allowing easier passage of the colonoscope (Saunders 1996), but this has been disputed in other studies (de Brouwer 2012; Mui 2004; Yoong 2004). The time to achieve caecal intubation can be used as a measure of this parameter. Given the indications for colonoscopy and its potential discomfort to patients, secondary outcomes measured will be polyp detection rate, degree of patient discomfort and the degree of colonic spasm.
Why it is important to do this review
Colonoscopy is a commonly performed intervention that can be uncomfortable for patients and IVH is variably used by endoscopists. Expediency and safety may be aided by IVH and this review aims to explore the evidence behind its use quickly and safely. Furthermore, reduction of colonic spasm may aid mucosal visualisation and hence polyp detection.