Rectal catheter

Lactulose may be given as a retention enema via a rectal balloon catheter. Do not use cleansing enemas containing soap suds or other alkaline agents. 

Perineum, rectum, and vagina Assess for contusions, hematomas, lacerations, and bleeding. Perform a rectal exam prior to placing a Foley catheter. A gynecologic exam should be performed. Perineal, rectal, and vaginal injuries may be the result of pelvic injuries. 

The availability of new routes of administration have led to increased utility and decreased opioid adverse drug reaction risk. Epidural and intrathecal administration through spinal catheters produces adequate regional analgesia at relatively low total doses compared with intravenous or oral routes. As such, spinal administration can thus minimize somnolence, nausea, vomiting, and respiratory depression associated with these medications. Other alternative routes include intranasal administration of butorphanol, and rectal and transdermal administration of fentanyl [28]. Availability of such options provides not only a decreased risk of adverse reactions, but also more comfortable measures for patients who would otherwise require continued intravenous administration, or for those who are unable to receive oral medication [28,29]. 

Historically, rectal or intravenous paraldehyde has been used for refractory GCSE. Although effective, it is extremely difficult to administer, is associated with serious adverse effects (e.g., hypotension, tachycardia, pulmonary edema, and polyethylene emboli), and is no longer manufactured in the United States. The only available formulation currently licensed is an enteral product that is difficult to obtain in a timely manner. If a rectal dose is given, it should be diluted 1 1 in vegetable oil and given every 20 minutes as needed via a rubber catheter."... 

Fig. 17.2. Two balloon rectal tubes commonly used to insufflate air in the bowel. Type A) is a 24 French flexible rubber Foley catheter, normally used for bladder catheterization type B) is a large bore rigid plastic tube with multiple lateral holes preferred in incontinent patients...

Taylor SA, Halligan S, Goh V et al (2003) Optimizing colonic distention for multi-detector row CT colonography effect of hyoscine butylbromide and rectal balloon catheter. Radiology 229 99-108... 

The basic equipment required for the CT colonography examination is little more than a red rubber catheter with a hand held insufflation bulb similar to that used for barium enema examinations. There are a variety of rectal catheters available of varying size, typically 5-15 mm in diameter. Although we routinely use a balloon-tipped enema catheter, many researchers now avoid balloon insufflation. Traditionally room air has been the gas of choice for colonic insufflation at CT colonography due to its availability and lack of additional expense. However, there is a growing body of evidence advocating the use of carbon dioxide (COj) which is associated with less abdominal cramps and is more rapidly reabsorbed (Yee and Galindo 2002). COj is supplied from a refillable cylinder via a disposable administration set which allows constant gas pressure influx with the facility to record both gas pressures and the volume of COj administered. 

A standard enema bag filled with approximately 31 of gas is an alternative to the plastic bulb insufflator (Fig. 5.4), and has the additional advantage of permitting manual insufflation of carbon dioxide. The bag (filled with air or carbon dioxide via a gas cylinder) is sealed with a plastic clip and attached to a rectal catheter via a connecting tube. Once the rectal catheter is in-situ, the clip is released and the bag is gently compressed over 2-3 min, insufflating the colon. Gentle insufflation improves patient tolerance and ultimately allows greater volumes of gas to be administered. If the bag is empty and more gas required, then the plastic seal can be opened and room air introduced. 

At the time of writing, the authors are aware of only one commercially available device specifically designed for colonic insufflation (Fig. 5.5, Protocol colon insufflation system, E-Z-EM Inc, Westbury, NY, USA). This system electronically controls the flow rate of carbon dioxide increasing over time in a step wise fashion from 1 to 3 L/min to prevent spasm (1 L/min for the first 0.5 L, 2 L/min from 0.5 to 1.0 L, and then 3.0 L/min thereafter). The total volume of gas administered is displayed continuously and, if intracolonic pressure (measured at the rectal catheter tip) increases beyond the limit set by the user (up to a maximum of 25 mm Hg), the system automatically shuts down to prevent further insufflation and so reduces the risk of colonic perforation. In the latest version, insufflation automatically ceases when a total of 4 L of gas have been administered and then for every 2 L administered beyond this. To recommence insufflation, the operator needs to manually override this additional safety feature by pressing the start button. 

Fig. 5.5. Automated colonic insufflator, connected to a thin rectal catheter, displaying the intralmninal rectal pressure and total volmne of carbon dioxide administered...

There is wider scope for using more flexible and thinner catheters during CT colonography compared to barium enema because of the requirement to transmit only gas and because the consequences of anal incontinence are less dramatic. The choice of rectal catheter will mainly depend on local availability, method of insufflation, and individual patient but there is some evidence suggesting that thin tubes are adequate for most circumstances. 

Perhaps the simplest catheter is a thin plastic or rubber tube, for example a standard 14F rectal tube (Jacques Nelaton rectal catheter Rusch, Bucks, UK) or a Foley catheter. The former was shown to be as effective as a standard inflatable rectal balloon catheter (Trimline DC E-Z-EM, Westbury, NY) for achieving adequate distension (Taylor et al. 2003). Alternatively, the Foley catheter is almost ubiquitous and can be used effectively when attached to a bulb insufflator. The soft tip allows safe insertion and it... 

Some groups advocate removing the tube for the second acquisition to enhance patient comfort and to facilitate subsequent rectal assessment. However, this issue is much less relevant with thin catheters. Even if using larger catheters, the advantage of being able to insufflate additional gas likely outweighs any potential benefit of early removal. 

Once the supine study has been acquired, the rectal catheter is left in situ and the patient asked to turn prone. A second scout is performed and if distension is deemed suboptimal, the pressure limit will be increased to 25 mm Hg to encourage further gas insufflation. A further scout is performed and when this demonstrates optimal insufflation, the second study is acquired. The examination is then complete and the rectal catheter removed. The patient is reassured that much of the insufflated gas will be absorbed (rather than expelled), and that any abdominal cramping should ease within a few minutes. 

There are several strategies available to the practitioner for optimising colonic distension and, if used appropriately, the time and effort invested will be rewarded by easier and more accurate interpretation. The authors recommend ongoing quahty assurance measures are adopted by all departments performing CT colonography in order to minimise failure rates due to inadequate distension. Finally, safety concerns about CT colonography will likely diminish with more judicious use of rectal balloon catheters. 

Although the rectum is straight and not mobile, one has to take care of not missing rectal lesions. False negative diagnosis of rectal lesions may be caused by readers fatigue if one starts at the cecal level, or by rectal balloon catheter hiding rectal lesions (Pickhardt and Choi 2005) (Fig. 8.6). 

Fig. 8.6a,b. False negative diagnosis rectal balloon catheter hiding rectal polyp a prone scan after removing the rectal balloon clearly shows a large stalked polyp (arrow) b the polyp is hidden by the rectal balloon on supine image.(orrow). Lesson Thidc rectal balloon catheters can hide rectal lesions. Therefore, remove rectal balloon catheter on prone scan... 

Slight increases can occur after rectal examination, passing a catheter, or in constipation. 

In many cases, no sedation is required except that provided by sterile Xylocaine (lidocaine) jelly that lubricates the catheter in boys. A quick examination performed by an experienced radiologist should not be painful. Postprocedural minor discomfort can occur, and it seems less worrisome when announced. Improvement by hydration and local care is the rule. In some children, major anxiety can be present. Inhalation of an equimolecular mixture of nitrous oxide and oxygen (Entonox) in fasting children can be helpful (Schmit and Sfez 1997). In uncooperative children who are too young to breathe gas, rectal midazolam can occasionally be used (Hypnovel 0.3 mg/kg, maximal dose 5 mg). For safety, sedation procedures should preferably be organized in collaboration with the department of anesthesiology. 

The rectum frequently fails to opacify after the injection of contrast material into the cloaca. In patients who have already had a colostomy, contrast material can be directly injected into the distal limb of the colostomy prior to retrograde cloacal injection. This technique regularly demonstrates the level of rectal occlusion and the presence of conunu-nication between other pelvic structures, making further cloacal injections unnecessary (Fig. 7.23). Most commonly, a balloon catheter is used to inject contrast material under moderate pressure to dem-... 

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