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144

Chapter 11

and analgesia (PSA) according to the Dutch national guidelines. An anaesthesiologist is

available for liaison, supervision and emergency help.

Insufflation of the duodenum during ERCP is done with CO

2

to reduce periprocedural pain

and abdominal distension in comparison to insufflation of air.

Patients are asked to complete a questionnaire before procedure to assess baseline pain

levels, drowsiness, nausea, perception, and mood using a Visual Analog Scales (VAS) (0-100).

Baseline assessments of the Modified Observer’s Assessment of Alertness/Sedation Scale

(MOAA/S), the Aldrete recovery score and measurements of heart rate (HR), non-invasive

blood pressure (NIBP), respiratory rate (RR), and oxygen saturation (SpO

2

) are recorded.

After placement of an intravenous line, an infusion of 500ml NaCl 0.9% is started at the rate

of 250 ml/h. Five minutes before insertion of the endoscope, glycopyrrolate 0.2 mg, and

lidocaine 50 mg are given iv. Then patients are asked to place themselves into the prone or

semiprone position. Two l/min of oxygen are administered by nasal cannula during ERCP,

and HR, SpO

2

, RR, ECG, NIBP, end-tidal carbon dioxide (etCO

2

), and sedation level measured

by the MOAAS/S are collected at 5-minute intervals. An independent, blinded observer

collects research data.

Both groups are sedated by a propofol Target Controlled Infusion (TCI) system (Propofol

1% MCT Fresenius). TCI means a weight pre-programmed system using a pharmacokinetic

model to attain a specific estimated propofol plasma target level.

6

We start propofol TCI in both groups with a targeted plasma level of 1.5 μg/ml.

Reaching this plasma level, group K is treated with esketamine (Ketanest S, Pfizer) 150 µg/

kg, group A receives alfentanil (Rapifen, Janssen-Cilag) 2.0 µg/kg.

After 2 minutes propofol TCI is stepped up – if needed - to a maximum-targeted plasma

level of 2.5 μg/ml.

Before starting the endoscopic procedure, patients are assessed for their level of sedation

using the MOAA/S scale yielding at a score of < 2. The modified form of the MOAA/S scale

uses not only the responsiveness component of the original scale (awake (5) - unresponsive

(1)) but is extended with assessment of painful stimuli. As reaction of painful stimuli are

still possible at anaesthetic levels that block reactions to verbal commands, prodding, or

shaking, they can be used to assess deeper sedation levels.

If MOAA/S is above 2, e.g. the patient does not sustain intervention, additional sedation is

provided with TCI increments of 0.5 μg/ml in plasma target level. These very small steps

are performed in order to avoid deep sedation. For every step up of propofol TCI additional

esketamine 50 µg/kg or alfentanil 1 µg/kg is added. Maximumdosage is 500 µg/kg ketamine

or 7.5 µg/kg alfentanil.

The total amount of all used medication (propofol, esketamine, alfentanil) as well as all time

periods (total procedure time, time between end of the endoscopy till patient is ready for

transport to the recovery unit) is noted.