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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.