Measurements
Baseline values of MBP and HR were defined as the lowest of the three measurements during 3 min interval just before TCI propofol. MBP and HR were measured and recorded at the designated time points and at a 3-min interval duration of endoscopic procedure. The designated time points: T0 = baseline values; T1 = the target concentration achieved after TCI propofol; T2= 3 min after esketamine injection; T3 = at scope intubation and T4-x = by 3-min intervals during the procedure.
Perioperative anaesthesia related adverse events, such as bradycardia, hypotension, frequency of respiratory depression, nystagmus, mental symptoms, and postoperative nausea and vomiting (PONV) were also recorded. TCI propofol was maintained till the removal of the colonoscopy. Recovery time was defined as the time from discontinuing propofol to Observer’s Assessment of Alertness/Sedation scale (OAA/S) = 5 (responds readily to name spoken in normal tone). The endoscopic time were also recorded.
The patient’s satisfaction with the procedure was assessed 45 min after endoscopic procedure as: 4, no discomfort; 3, slightly uncomfortable; 2, extremely uncomfortable; 1, unacceptable. The gastroenterologist’s satisfaction (4 = excellent, 3 = good, 2 = fair, 1 = poor) was assessed immediately after endoscopic procedure [15].
The primary endpoint was the median effective concentration (ED50) of propofol with different doses of esketamine during gastrointestinal endoscopy in elderly patients. The secondary endpoint was to compare the change of haemodynamics among three groups: the average percent change to baseline in MBP and HR. We defined that percent change at the designated time points = (MBPT1-x– MBPT0)/ MBPT0* 100.