Introduction
Gastrointestinal endoscopy is an essential screening and therapeutic
tool for gastrointestinal diseases. It is important to perform
endoscopic procedures under sedation for higher patient comfort and
acceptance [1,2]. Propofol, a good hypnotic with rapid onset, rapid
recovery, and minimal side effects, is the most widely used in
anesthesia induction and maintenance during endoscopic procedures
[3-7]. However, propofol may result in hypotension, bradycardia,
respiratory depression, and loss of protective reflexes [8],
especially in elderly patients. Adjuvants are usually needed in many
cases because co-administration can improve anaesthetic efficacy and
reduce the incidences of adverse events caused by a single drug [9].
Esketamine, a noncompetitive, N-methyl-D-aspartate receptor antagonists
[10], has analgesic, anaesthetic and sympathomimetic properties and
is known to cause less cardiorespiratory depression [11,12].
Therefore, it could be an ideal adjunct to propofol for endoscopic
procedures [12,13]. However, very few studies have been reported the
effectiveness and safety of esketamine adjunct to propofol sedation
during endoscopic procedures in elderly patients.
We therefore designed this randomized, double-blinded and controlled
study to assess the effectiveness and safety of esketamine as an adjunct
to propofol target-controlled infusion (TCI) and determine the effect of
different doses of esketamine on the median effective concentration
(EC50) of propofol for gastrointestinal endoscopy in
elderly patients.