

148
Chapter 11
an analgesic at the same time. Varadarajulu et al.
13
demonstrated that the use of ketamine
in difficult to sedate patients undergoing ERCP resulted in better quality and depth of
sedation and analgesia. They observed shorter recovery times compared with opiate and
benzodiazepine sedation. However, they concluded that it is necessary to conduct further
randomised trials. Wehrmann et al.
14
recommended the combination of propofol with
ketamine because of its analgesic properties without cardiorespiratory depressant effects.
Mortero et al.
8
found that the combination of propofol and ketamine in small doses
attenuates hypoventilation, produces positive mood effects without perceptual changes,
and provides faster recovery of cognition in comparison to propofol alone duringmonitored
anaesthesia.
Ketamine is a favourable drug in haemodynamically instable patients. Despite its effective
anaesthetic and analgesic effects, spontaneous breathing and airway reflexes aremaintained
and hypotension is less common due to an increase in sympathetic tone. Its s-enantiomer
esketamine has been shown to be even more potent with an approximately 3-4 fold
anaesthetic potency compared to racemic ketamine. The most common concerns about
esketamine, however, are related to its mind-altering effects in cognition. It can produce
psychotomimetic effects that may be associated with symptoms similar to dissociative
states of mind.
15
On the other hand, Nakao et al.
16
showed that propofol used in clinical
relevant dosages suppresses these effects via the activation of Gamma-Amino Butyric Acid
(GABA) receptors. Unfortunately, there are only a few studies with only limited significance
investigating the effectiveness of a propofol/esketamine regime with emphasis on the
aforementioned safety aspects during ERCP and the eventually psychotomimetic effects
such as visual disturbances, vertigo, or nausea that could compromise patient satisfaction
and recovery after discharge home.
The aim of our trial is to show that the synergy of esketamine and propofol can provide a
better safety and satisfaction profile than the combination with an opioid during ERCP.