A randomized double-blind placebo controlled trial to evaluate the value of a single bolus intravenous alfentanil in CT-colonography

Pain during CT-colonography is common. Apart from the discomfort and anxiety
during the procedure for symptomatic patients, this influences the adherence of
CT-colonography as a possible screening tool for colorectal cancer. A short
acting opioid as used in colonoscopy, such as alfentanil, will reduce pain and
burden and thereby increase acceptance of CT-colonography. We hypothesize that
alfentanil will reduce maximum pain by at least 1.3 point on a 11-point numeric
rating scale scale and increase the acceptance of CT-colonography. (see for
more background the protocol page 9)

Primary Objective: To evaluate whether a single intravenous alfentanil bolus
(7.5 mcg/kg) has a clinically significant analgesic effect in clinical patients
who undergo an elective CT-colonography compared to placebo. We have defined a
clinically significant effect as a pain reduction of 1.3 point on an 11-point
numeric rating scale.

Secondary Objectives:
To assess differences in:
*Pain score in all insufflation positions (right and left decubitus, supine and
prone) and the average pain score
*Pain and burden of all CT-colonography aspects (Telebrix, cannula insertion,
insufflation) and total pain and burden of CT-colonography
*Side-effects of alfentanil during CT-colonography including:
- respiratory effects (apnoea, respiratory frequency and blood
oxygenation)
- hemodynamics (heart rate and blood pressure)
*Procedure and recovery time
*The most painful and most burdenful aspect of CT-colonography

Prospective double-blind randomized placebo controlled trial.

Two questionnaires with approximately 15 multiple-choice questions shall be
given during
this study: the first before randomization and the second after completion of
the CT-colonography procedure (appendix 1 and 2).
Oxygen saturation, heart rate and blood pressure will be measured during the
CT-colonography procedure, using a pulse oxymeter and automated blood pressure
monitor.
The participants randomized to group 1 will receive alfentanil (Rapifen;
Janssen-Cilag, Tilburg, The Netherlands) 7.5 mcg/kg intravenously through the
cannula. The participants from group 2 will receive a placebo, in this study a
0.9% saline solution. This placebo is chosen because alfentanil is dissolved in
0,9% saline solution. Both the physician performing the CT-colonography scan as
well as the patient are blinded to the allocated group.

- Two questionnaires with approximately 15 multiple-choice questions
- Monitoring oxygen saturation and blood pressure during the procedure, using a
pulsoximeter and automated blood pressure monitor. And asking the patient 4
times for a pain score during the insufflation.
- The need for an intravenous cannula in the arm, which is not always necessary
in routine clinical practise (although always intra venous medication is
administrated during CT-colonography).
- Adverse events, such as: respiratory depression, apnoea, transient
hypotension, bradycardia, dizziness, nausea and vomiting (only for the
participants randomized to group 1 may experience side-effects of alfentanil)
The risk of serious adverse events is very small with the low dose alfentanil
used in this study. For example in a study of Usta et al. a combination of a
benzodiazepine and alfentanil low dose even did not cause any serious adverse
events. (see chapter 6.5 of the protocol, page 17)
- Approximately 45 minutes extra time for observation/monitoring after the
procedure.