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INTRODUCTION AND OUTLINE OF THE THESIS
Chapter 6
addresses the “analgesic - only” approach during CT colonography – a procedure
which is due to the colonic insufflation comparable to colonoscopies regarding pain
experience.
20
We conducted a double blind placebo-controlled randomised multi-centre trial in ninety
patients scheduled for elective CT colonography. After randomisation patients were
allocated to get either placebo or alfentanil for pain therapy. Alfentanil is a µ-receptor agonist
that has its maximal effects within 1 to 2 minutes after injection. It acts dose-dependent. This
characteristic renders possible, to titrate alfentanil till the planned level of consciousness is
reached. Primary objective was the difference in pain experience between both groups
measured on an 11-point numeric rating scale (NRS). In this trial, alfentanil was applied
under continuous monitoring of SpO
2
, but without attendance of an anaesthesiologist or
specialised sedation practitioner.
In
Chapter 7
we again address the “analgesic – only” question.
21
In a prospective
randomised trial we investigated satisfaction of patients and endoscopists, and concurrent
safety aspects of an “alfentanil - only’’ strategy compared to two other common forms of
analgo-sedation in patients scheduled for colonoscopy. 180 patients were randomised in
three groups: group A: alfentanil – solely an analgesic, group M: midazolam combined with
fentanyl - a combination of analgesia and mild sedation, and group P: propofol combined
with alfentanil – a combination of analgesia and deep sedation; in group A and M, analgo-
sedatives were given by the attending endoscopy nurse and in group P by a specialised
sedation practitioner. Cardiorespiratory parameters as ECG, heart rate (HR), non-invasive
blood pressure (NIBP), oxygen saturation (SpO
2
), and end-tidal carbon dioxide (etCO
2
),
and interventions were monitored. After procedure, endoscopists and patients completed
questionnaires related to their experiences with endoscopy.
Chapters 8 and 9
address with dexmedetomidine a new substance for moderate
procedural sedation. Dexmedetomidine is a short-acting selective alpha
2
-adrenoceptor
agonist with anxiolytic, hypnotic, and analgesic properties without respiratory side effects.
This sounds like the ideal analgo-sedative for moderate sedation. Analgesic and anxiolytic
effects combined with the properties of an ideal sedative (e.g. a fast begin and termination
of action, the possibility to titrate to a planned sedation level, nevertheless a fast recovery,
combined with an superior safety profile, and without the necessity for extra personnel).
22,23
Propofol as the gold standard provides superior sedation with a fast begin and end of
action. However, drawback of propofol sedation is the risk to progress from moderate to
deep sedation or even general anaesthesia with impaired cardiorespiratory functions.
Therefore, pharmacological agents like dexmedetomidine that have analgo-sedative effects
without the risk of respiratory problems are of increasing interest.