

86
Chapter 7
nurse specialised in sedation, both — according to our hospital sedation protocol —
providing comparable periprocedural care for the patient. However, it was not possible
to blind the attending parties (observer, endoscopist, endoscopic, and anaesthesia nurse).
Colonoscopies were started by residents under supervision and in difficult cases completed
by staff members.
Patients 18 years of age, American Society of Anesthesiologists (ASA) class I–III, and
scheduled for elective colonoscopy were eligible and invited to participate. Patients with
a history of allergic reaction to any drug in the three regimens, unregulated hypertension,
bradycardia, arrhythmia, or serious COPD were excluded.
Procedure
To create comparable sedation conditions, we used the observer assessment of alertness/
sedation scale (OAA/S).
9
The OAA/S — originally only validated for benzodiazepines— is
based on a combination of observations of the resting patient, and patient`s responses to
verbal commands with increasing intensity. It ranges from 1 (does not respond) till 5 (alert).
Our targeted sedation score was OAA/S < 4.
To quantify pain, we asked patients to specify suffered pain on the Numeric Rating Scale
(NRS). NRS 0 thereby represents no pain, and NRS 10 maximum pain level patients could
imagine. The goal aimed was a NRS score < 4.
Each patient in group A received alfentanil (Rapifen, Janssen-Cilag B.V., Tilburg, Belgium) 10
μg/kg intravenously, before starting colonoscopy to achieve the targeted score OAA/S < 4.
If the patient reported pain (NRS > 4) during the procedure, the endoscopy nurse was
allowed to administer extra bolus doses of alfentanil 2.5 μg/kg.
Following common hospital standards, patients in group M received at the same time a
standard dose of midazolam (MidazolamActavis, Hafnarfjördur, Iceland) 2.5mg and fentanyl
(Fentanyl Braun, Melsungen, Germany) 50 μg by the endoscopy nurse, irrespectively of
their weight. If OAA/S < 4 score was not reached, another 2.5 mg midazolam, and if the
patient expressed pain (NRS > 4), 50 μg fentanyl was added. Patients in group P received a
bolus dose of 100 μg alfentanil and sedation with a target-controlled infusion (TCI) propofol
(Propofol–Lipuro, Braun, Melsungen, Germany) by an anaesthesia nurse to reach an OAA/S
< 4. Additional pain (NRS > 4) was treated with an extra dosage of 100 μg alfentanil.
Baseline measurements
Before colonoscopy, patients were asked to assess the pain level they expected to suffer
during colonoscopy on a NRS.
Furthermore, patients had to accomplish the Trieger test
10
before and 30 min after
procedure. This test is validated to show the psychomotoric recovery following anaesthesia.
Here, the post- versus pre-procedural score was rated.