Objective To prospectively determine the median effective dose (ED50) of propofol for inhibiting a response to laryngeal mask airway (LMA) insertion when combined with different doses of esketamine in female patients. Methods Fifty-eight female patients (aged 20-60, ASAⅠ-Ⅱ) scheduled for elective hysteroscopy were enrolled and randomly divided into two groups, one administered 0.2 mg/kg of esketamine (K1 group, n = 28) and the other 0.3 mg/kg of esketamine (K2 group, n = 30). The two groups received the corresponding doses of esketamine intravenously, followed by an intravenous injection of propofol (injection time was 30 s). The initial dose of propofol was 2 mg/kg, and the dose ratio of propofol in the adjacent patients was 0.9. If there was a positive reaction to LMA insertion, the dose ratio in the next patient was increased by one gradient, and if not, the dose ratio was decreased by one gradient. The median effective dose (ED50), 95% effective dose (ED95) and 95% confidence interval (95%CI) of propofol for inhibiting a response to LMA insertion in the two esketamine groups were calculated using a probit analysis.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
58
Patients received 0.2 mg/kg of esketamine intravenously for 30 s，after 120 s of propofol and disappearance of the eyelash reflex, a laryngeal mask was inserted. The test was performed using the sequential method. The initial dose of propofol was 2 mg/kg, which can be easily inserted into the LMA, and the propofol dose ratio of the adjacent patient was 0.9. If there was a positive reaction to the LMA insertion, the gradient was increased for the next patient; otherwise, the gradient was decreased, and the study was terminated after seven crossover inflection points.
Patients received 0.3 mg/kg of esketamine intravenously for 30 s，after 120 s of propofol and disappearance of the eyelash reflex, a laryngeal mask was inserted. The test was performed using the sequential method. The initial dose of propofol was 2 mg/kg, which can be easily inserted into the LMA, and the propofol dose ratio of the adjacent patient was 0.9. If there was a positive reaction to the LMA insertion, the gradient was increased for the next patient; otherwise, the gradient was decreased, and the study was terminated after seven crossover inflection points.
Liang-Yuan Lu
Beijing, Beijing Municipality, China
Record of the patient response during LMA placement
body movement or no body movement. Body movement is defined as cough, breath-holding or laryngospasm when the LMA is inserted or the laryngeal cuff inflated, and the patient has difficulty opening the mouth and conscious movement all over the body. No body movement is defined as the absence of these reactions when the LMA is inserted or the laryngeal cuff is inflated.
Time frame: 1 minutes
Overall condition of LMA placement
mouth opening ≥3 cm is complete and \<3 cm is incomplete. The LMA placement conditions are as follows: 1 = complete relaxation, 2 = mild resistance, 3 = resistance but can open the mouth, 4 = resistance and the need to further increase the propofol dose; 1 and 2 are considered successful LMA placement and 3 and 4 are failure
Time frame: 1 minutes
Record related indicators
Record of the mean arterial pressure (MAP)
Time frame: 1 minutes
Record related indicators
Record of the mean arterial pressure (MAP)
Time frame: 2 minutes
Record related indicators
heart rate (HR)
Time frame: 1 minutes
Record related indicators
heart rate (HR)
Time frame: 2minutes
Record of additional doses of propofol and the adverse reactions of positive patients during the induction process (hypotension, bradycardia and apnoea, etc.)
If the patient develops bradycardia (\<45 beats/min), 0.3-0.5 mg of intravenous atropine is given, and 1-2 mg of intravenous dopamine is administered for hypotension (\<20% of basal blood pressure)
Time frame: 1 minutes
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