OBJECTIVE: This study aimed to estimate the median effective dose of intrathecal isobaric ropivacaine without opioid required for adequate cesarean delivery anesthesia after epidural labor analgesia.
METHODS: Patients aged 20-40 years with American Society of Anesthesiology scores of I-II, body mass index ≤ 36, who underwent emergency cesarean delivery after failed vaginal delivery with epidural analgesia of a duration ≤ 6 h were included in the study. After removal of the epidural used for labor analgesia, a new combined spinal epidural was performed, and a dose of intrathecal isobaric ropivacaine without opioid was administered. The dose was determined using up-down methodology, with the starting patient\'s dose set to 12 mg. Adequate anesthesia, defined as a pinprick level no lower than T6 at 5 min after ropivacaine administration, resulted in the next patient receiving a dose of ropivacaine 1 mg higher, and inadequate anesthesia 1 mg lower. The primary outcome was the median (95% confidence interval (CI)) dose of spinal ropivacaine required for adequate cesarean delivery anesthesia.
RESULTS: Of the 46 patients included in the study, 40 were analyzed. The median spinal ropivacaine dose was 8.11 mg (95% CI 7.29-8.93 mg) by the Dixon and Mood method and 8.06 mg (95% CI 6.93-9.00 mg) by isotonic regression. Two patients had high spinal anesthesia.
CONCLUSIONS: Our findings suggest that for 50% of patients undergoing cesarean delivery after failed vaginal delivery with epidural analgesia, an 8-mg spinal dose of isobaric ropivacaine without opioid provides an anesthesia level no lower than T6 at 5 min.

UNASSIGNED: 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.
UNASSIGNED: A total of 58 female patients (aged 20-60 years, ASAⅠ-Ⅱ) scheduled for elective hysteroscopy were enrolled and randomly divided into 2 groups, one of which was 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 2 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 a positive reaction occurred due to LMA insertion, the dose ratio in the next patient was increased by 1 gradient; if not, the dose ratio was decreased by 1 gradient. The ED50, 95 % effective dose (ED95) and 95 % confidence interval (CI) of propofol for inhibiting a response to LMA insertion in the 2 esketamine groups were calculated using probit analysis.
UNASSIGNED: The ED50 of propofol for inhibiting a response to LMA insertion in female patients was 1.95 mg/kg (95 % CI, 1.82-2.08 mg/kg) in the K1 group and 1.60 mg/kg (95 % CI, 1.18-1.83 mg/kg) in the K2 group. The ED95 of propofol for inhibiting a response to LMA insertion in female patients was 2.22 mg/kg (95 % CI, 2.09-2.86 mg/kg) in the K1 group and 2.15 mg/kg (95 % CI, 1.88-3.09 mg/kg) in the K2 group.
UNASSIGNED: Propofol combined with 0.3 mg/kg of esketamine has low ED50 and ED95 effective doses for inhibiting an LMA insertion response in female patients undergoing hysteroscopy and surgery. There were no significant adverse effects, but the additional dose of propofol and airway pressure were significantly higher than those in the group administered 0.2 mg/kg of esketamine. Based on the results, we recommend the combination of propofol with 0.2 mg/kg esketamine for optimal conditions during LMA insertion in women undergoing hysteroscopy.

The incidence of emergence delirium (ED) is higher in preschool children undergoing tonsillectomy and/or adenoidectomy. The purpose of this study was to determine the median effective dose (ED50) of dexmedetomidine (DEX) for the inhibition of ED in preschool children by using probit regression analysis. A total of 140 anesthesia records were retrieved and divided into seven groups based on the infusion rate of DEX: .2, .25, .3, .35, .4, .45, and .5 μg·kg-1·h-1. The Pediatric Anesthesia Emergence Delirium Scale (PAEDS) was used to assess ED in preschool children, and ED was defined as a PAEDS score ≥ 10. Probit regression analysis revealed that the ED50 and ED95 of DEX were .31 μg·kg-1·h-1 (95% CI: .29-.35) and .48 μg·kg-1·h-1 (95% CI: .44-.56), respectively. Probit(p) = -2.84 + 9.28 × ln (Dose), (χ2 = 1.925, P = .859). The PAEDS score was significantly increased in the ED group, and the rate of bradycardia was significantly decreased in the ED group compared with the without ED group (27.3% vs 54.1%, P = .02). DEX can effectively inhibit the ED in preschool children undergoing tonsillectomy and/or adenoidectomy, however, bradycardia was the main complication.

BACKGROUND: Intravenous lidocaine could be a potential alternative adjuvant to propofol-based sedation for gastroscopy in elderly patients. This study aimed to evaluate the effect of intravenous lidocaine on the median effective dose (ED50) of propofol induction dose in elderly patients undergoing painless gastroscopy.
METHODS: The study included 70 patients aged ≥ 60 years undergoing painless gastroscopy with 64 randomly assigned to either group L (2% lidocaine 1.5 mg/kg, n = 31) or group N (equal volume normal saline, n = 33). All patients received propofol induction following 0.1 μg/kg intravenous sufentanil. The Dixon \"up-and-down\" sequential method was used, with a 1.5 mg/kg initial induction dose of propofol followed by a 0.1 mg/kg sequential variable dose. The primary endpoint was the ED50 of the propofol induction dose. The total propofol dose, recovery time, adverse events, and local anesthetic intoxication reactions were also recorded.
RESULTS: The ED50 of propofol induction dose was 0.670 (95% confidence interval [CI] 0.216-0.827) mg/kg in group L and 1.118 (95% CI 0.803-1.232) mg/kg in group N. There was a statistically significant difference between the two groups (p < 0.001). The incidence of hypotension and propofol injection pain were lower in group L than in group N (p < 0.05). Furthermore, the orientation recovery time in group L was shorter compared to group N (p < 0.05). None of the participants in group L observed local anesthetic intoxication reactions after receiving lidocaine.
CONCLUSIONS: The administration of intravenous lidocaine to elderly patients undergoing painless gastroscopy resulted in a significant 40% reduction in the ED50 of propofol induction dose, which may be related to the decreased incidence of hypotension and injection pain, as well as the improved post-gastroscopy orientation recovery.
BACKGROUND: ChiCTR, ChiCTR2200065530. Registered on 08 November 2022.

UNASSIGNED: Inhalational technique is used to induce anaesthesia in children without intravenous access. We aimed to determine the median effective dose (ED50) of intranasal dexmedetomidine to ensure satisfactory mask acceptance during inhalation induction in children with retinoblastoma undergoing examination under anaesthesia.
UNASSIGNED: A prospective sequential allocation study was conducted in children aged 1-60 months divided into Group A (1-18 months) and Group B (18-60 months). Children were administered dexmedetomidine intranasally as premedication. Sedation was assessed using the modified Observer Assessment of Alertness and Sedation Scale until induction. Successful mask acceptance was defined as a cooperative or asleep child during inhalational induction. The starting dose of dexmedetomidine was 1 µg/kg. The next dose varied by 0.2 µg/kg depending on the outcome of this case. According to the Dixon up-and-down method, the mean of midpoints of the failure-success sequence was calculated to obtain the ED50 values.
UNASSIGNED: The ED50 of intranasal dexmedetomidine for satisfactory mask acceptance was 0.7 µg/kg (95% confidence interval [CI]: 0.54-0.86) in Group A (n = 23) and 0.96 µg/kg (95% CI: 0.83-1.08) in Group B (n = 25) (P = 0.020). The mean (standard deviation) duration of anaesthesia was 33.5 (14.9) minutes in group A versus 23.5 (8.48) minutes in Group B (P = 0.007).
UNASSIGNED: ED50 was lower in children younger than 18 months than in older children. There was no difference in the time to discharge from the post-anaesthesia care unit despite the procedure being longer in smaller children.

UNASSIGNED: Propofol-opioids are the most common drug combination and can reduce the dose of propofol and the incidence of adverse events in painless artificial abortion. We hypothesized that butorphanol may reduce the median effective dose (ED50) of propofol, propofol injection pain, and postoperative uterine contraction pain.
UNASSIGNED: This was a randomized, double-blind, controlled study. A total of 54 female patients, who had ASA I or II, aged 18-49 years, undergoing painless artificial abortion, were randomly assigned into two groups, namely, Group P (propofol) and Group PB (propofol plus 10 μg/kg butorphanol). According to the pre-experiment, the initial dose of propofol for the P and PB groups was 3 and 2.5 mg/kg, respectively, with a dose gradient of 0.25 mg/kg. The ED50 of propofol was analyzed using probit regression analysis. The total propofol dose consumed, recovery time, and anesthesia-related adverse events were also recorded.
UNASSIGNED: There were 25 and 29 patients in the P and PB groups, respectively. The ED50 (95% CI) of propofol for artificial abortion were 2.477 (2.186-2.737) and 1.555 (1.173-1.846) mg/kg in the P and PB groups, respectively. The total propofol dose consumed was (150.7 ± 21.7) mg and (110.4 ± 28.2) mg in the P and PB groups, respectively (P < 0.001). Compared with the P group, injection-site pain (76 vs. 20.7%) and uterine contraction pain (72 vs. 6.9%) in the PB group had a significant decrease (P < 0.001).
UNASSIGNED: Combination of propofol with 10 μg/kg butorphanol reduced the ED50 of propofol and decreased the incidence of propofol injection-site pain and postoperative uterine contraction pain during painless artificial abortion compared with propofol alone.
UNASSIGNED: https://www.chictr.org.cn/showproj.html?proj=166610, identifier: ChiCTR2200059795.

BACKGROUND: Rocuronium intravenous pain is common in induction of general anesthesia. The aim of our study was to determine the median effective dose (ED50) of prophylactic intravenous remifentanil for the prevention of rocuronium injection pain and to explore the effect of age on the ED50.
METHODS: Eighty-nine adult patients undergoing elective general anesthesia, ASA I or II, regardless of gender or weight, were stratified according to age: group R1 18-44 years, group R2 45-59 years, and group R3 60-80 years. The initial dose of prophylactic remifentanil before rocuronium injection was set at 1 μg/kg lean body weight (LBW). The remifentanil doses were adjusted according to the degree of injection pain using the Dixon sequential method, with a ratio of 1.1 between adjacent doses. Injection pain was graded, and the occurrence of injection pain and adverse reactions were recorded. The ED50 and 95% confidence intervals (CIs) of remifentanil were calculated using the Dixon-Massey formula. Patients were asked whether they recalled feeling any injection pain in the post-anesthesia care unit (PACU).
RESULTS: The ED50 (95% CIs) of prophylactic remifentanil for the prevention of rocuronium injection pain were 1.266 μg/kg (1.186-1.351 μg/kg), 1.188 μg/kg (1.065-1.324 μg/kg), and 1.070 μg/kg (1.014-1.129 μg/kg) LBW in group R1, group R2, and group R3, respectively. No adverse reactions to remifentanil occurred in any group. In PACU, 84.6, 86.7, and 85.7% of patients who experienced injection pain had memories of the pain in group R1, group R2, and group R3, respectively.
CONCLUSIONS: Prophylactic intravenous remifentanil can prevent rocuronium injection pain, and its ED50 decreases with age, with 1.266 μg/kg (18-44 years), 1.188 μg/kg (45-59 years), and 1.070 μg/kg LBW (60-80 years), respectively.
BACKGROUND: ClinicalTrials.gov: NCT05217238 (registration date 18 Dec 2021).

UNASSIGNED: This study aimed to test the effect of different doses of intravenous lidocaine on the median effective dose (ED50) and 95% effective dose (ED95) of propofol-induction dose and identify the optimal dose.
UNASSIGNED: Patients undergoing first-trimester uterine aspiration were screened and randomly enrolled into the following groups: saline (L0), 0.5 mg/kg lidocaine (L0.5), 1.0 mg/kg lidocaine (L1.0), and 1.5 mg/kg lidocaine (L1.5). Anesthesia was induced with 1.0 µg/kg fentanyl. Prepared lidocaine or saline solution was injected later according to allocation, followed by propofol. The dose of propofol for each patient was determined using the up-and-down sequential study design. The primary end point was the ED50 and ED95 of the propofol-induction dose. The total propofol doses, awakening time, and adverse events were recorded.
UNASSIGNED: The ED50 (95% confidence interval) of propofol was significantly lower in groups L1.0 and L1.5 than group L0 (1.6 [1.5-1.7] mg/kg and 1.8 [1.6-1.9] mg/kg, versus 2.4 [2.3-2.5] mg/kg, respectively; p<0.001). There was no significant difference in ED50 between groups L1.0 and L1.5 (p>0.05). However, surprisingly, the ED50 was significantly higher in group L0.5 than L0 (2.8 [2.6-3.0] mg/kg vs 2.4 [2.3-2.5] mg/kg; p<0.05). The total doses of propofol in groups L1.0 and L1.5 were lower than those in groups L0 and L0.5 (p<0.05). The systolic blood pressure (SBP) decline after anesthesia induction in group L0.5 was greater than that in group L0 (p<0.01). The incidence of respiratory depression in group L0.5 was greater than that in groups L0 and L1.0 (p<0.05).
UNASSIGNED: In patients who underwent first-trimester uterine aspiration, intravenous lidocaine 1.0 mg/kg prior to propofol injection significantly reduced the ED50 of propofol induction dose without severe side effects, equivalent to the effect of 1.5 mg/kg dose. We recommend 1.0 mg/kg as the optimal dose.

Laryngeal mask airway(LMA) have been widely used in clinical practice. Irritation to the patient during the insertion of a laryngeal mask can cause hemodynamic fluctuations, which is particularly unsafe for geriatric patients. We used probit regression analysis to determine the median effective dose of sufentanil to inhibit the response to LMA insertion in geriatric patients.
A total of 90 patients were selected for the study using the following inclusion criteria: age ≥ 65 years old, ASA grade I-III, and scheduled to undergo intravenous general anesthesia with LMA insertion. Each patient received a dose of sufentanil for anesthesia induction in one of six levels: 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3 μg kg-1. LMA insertion was scored with a 3-point, 6-category scale, with scores ≥ 16 indicating effective LMA insertion, and < 16 indicating ineffective LMA insertion. Mean arterial blood pressure (MAP), heart rate (HR), and bispectral index (BIS) were recorded 1 min before induction (T1), 1 min after induction (T2), 1 min after LMA insertion (T3), and 5 min after LMA insertion (T4) in each group. In addition, the plasma norepinephrine (NE) levels and adverse reactions were measured at T2 and T3 in each dosage group.
Probit regression analysis showed that the ED50 of sufentanil inhibiting the response to LMA insertion in geriatric patients was 0.18 μg kg-1 (95% CI: 0.16-0.21 μg kg-1), and the ED95 was 0.31 μg kg-1 (95% CI: 0.27-0.38 μg kg-1), and the probit(p) = -2.34 + 12.90 × ln(Dose)([Formula: see text] = 0.725, p = 0.948). Among all the patients, the number of effective LMA insertions was 57 (group A), and the number of ineffective LMA insertions was 33 (group B). The MAP, HR, and NE in group B were significantly higher than in group A at T3.
Sufentanil can effectively inhibit the patient\'s response to LMA insertion, with stable hemodynamics and small stress response. The ED50 and ED95 were 0.18 μg kg-1 (95% CI: 0.16-0.21 μg kg-1) and 0.31 μg kg-1(95% CI: 0.27-0.38 μg kg-1), respectively.
This study was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2100051827 ) on October 6, 2021.

OBJECTIVE: Propofol and esketamine are routine anaesthetics used in sedation or general anaesthesia for paediatric procedures. Coadministration could reduce the dose of either propofol or esketamine required and lower the incidence of drug-related adverse events. We designed a four-arm randomized controlled trial in children undergoing diagnostic upper gastrointestinal endoscopy to investigate the dose of propofol with different doses of esketamine inducing appropriate depth of anaesthesia in 50% patients (median effective dose, ED50 ).
METHODS: After getting the approval of the research ethics committee and informed consent, 92 paediatric patients planning for upper gastrointestinal endoscopy were divided into four groups randomly: esketamine 0, 0.25, 0.5 and 1 mg/kg groups (n = 23/group). Propofol doses followed the Dixon and Massey up-and-down method with different starting and interval doses between groups. During the first attempt of endoscope insertion, if patients\' reactions prevented the insertion, it would be considered as a failure. The awakening time, total propofol doses, as well as the perioperative and post-procedure adverse events were evaluated and recorded for each patient.
CONCLUSIONS: The ED50 (median, 95% confidence interval) of propofol was significantly greater in esketamine 0 and 0.25 mg/kg groups in comparison with the esketamine 0.5 and 1 mg/kg groups (4.1 [3.3-4.9]; 3.1 [2.5-3.8] mg/kg vs. 1.8 [1.1-2.4]; 0.8 [0.2-1.3] mg/kg, respectively, p < .05). The total doses of propofol in esketamine 0.5 and 1 mg/kg groups were statistically lower than these in esketamine 0 and 0.25 mg/kg group (p < .01). The mean blood pressure was lower in the esketamine 0 mg/kg group than that in 1 mg/kg group after administration and during the procedure (p < .01). The esketamine 1 mg/kg group showed a higher incidence of vomiting and visual disturbances than the other three groups (p < .001).
CONCLUSIONS: In children who accomplished diagnostic paediatric upper gastrointestinal endoscopy under deep sedation/anaesthesia, the total dosage of propofol needed was reduced significantly in esketamine 0.5 and 1 mg/kg groups with a corresponding reduce in propofol-related hemodynamic changes. However, a higher incidence of esketamine-related adverse effects was found in esketamine 1 mg/kg group.