The Ropivacaine Concentration Required for Ultrasound-Guided Ilioinguinal/Iliohypogastric Nerve Block in Pediatric Patients

Optimizing nicardipine dosage for effective control of pituitrin-induced hypertension in laparoscopic myomectomy undergoing total intravenous anesthesia

BACKGROUND

This study aimed to determine the median effective dose (ED50) and 95% effective dose (ED95) of nicardipine for treating pituitrin-induced hypertension during laparoscopic myomectomy, providing guidance for the management of intraoperative blood pressure in such patients.

METHODS

Among the initial 40 participants assessed, 24 underwent elective laparoscopic myomectomy. A sequential up-and-down method was employed to ascertain the ED50 of nicardipine based on its antihypertensive efficacy. Nicardipine was initially administered at 6 µg/kg following the diagnosis of pituitrin-induced hypertension in the first patient. Dosing adjustments were made to achieve the desired antihypertensive effect, restoring systolic blood pressure and heart rate to within ± 20% of baseline within 120 s. The dosing increment or reduction was set at 0.5 µg/kg for effective or ineffective responses, respectively. The ED50 and ED95 of nicardipine were calculated using Probit regression by Maximum Likelihood Estimation (MLE) to establish dose-response curves and confidence intervals.

RESULTS

24 patients were included for analysis finally. The ED50 and ED95 of nicardipine for blood pressure control after pituitrin injection were determined. The study found that the ED50 of nicardipine for treating pituitrin-induced hypertension was 4.839 µg/kg (95% CI: 4.569-5.099 µg/kg), and the ED95 was estimated at 5.308 µg/kg (95% CI: 5.065-6.496 µg/kg). Nicardipine effectively mitigated the hypertensive response caused by pituitrin without inducing significant tachycardia or hypotension.

CONCLUSIONS

Nicardipine effectively controlled blood pressure after pituitrin injection during laparoscopic myomectomy, with ED50 and ED95 values established. This research highlights the potential utility of nicardipine in addressing hypertensive responses induced by pituitrin, particularly in clinical settings where pituitrin is routinely administered.

The Ropivacaine Concentration Required for Ultrasound-Guided Rectus Sheath Block in Pediatric Patients Undergoing Single-Incision Laparoscopic Hernia Repair: A Sequential Allocation Dose-Finding Study

BACKGROUND

The local anesthetic concentration required for ultrasound-guided rectus sheath block (RSB) in children remains unknown. Knowledge of appropriate ropivacaine concentration can help clinicians reduce local anesthetic toxicity risk when performing ultrasound-guided RSB in children. This study aimed to determine the appropriate ropivacaine concentration for ultrasound-guided RSB in children undergoing laparoscopic inguinal hernia repair.

METHODS

In this single-arm prospective study with an up-down sequential allocation design of binary response variables, 18 consecutive children aged 11 months to 7 years undergoing single-incision laparoscopic percutaneous extraperitoneal closure were assessed. Orotracheal intubation was performed without intravenous anesthesia or a neuromuscular relaxant. After intubation, ultrasound-guided RSB was performed with a ropivacaine dose of 0.30 ml/kg (0.15 ml/kg per side). Dixon's up-and-down method was used to determine the concentration, starting from 0.25% in 0.05% increments. Surgery commenced ≥15 min following RSB. Body movement or a 20% increase in heart rate or systolic blood pressure within 1 min of surgery initiation determined an unsuccessful RSB. The 95% effective concentration of ropivacaine needed for successful RSB was calculated using the probit test.

RESULTS

The 95% effective concentration of ropivacaine needed for successful ultrasound-guided RSB was 0.31% (95% confidence interval, 0.25-7.29). The highest concentration of ropivacaine required for successful ultrasound-guided RSB in the group of patients in this study was 0.3%.

CONCLUSION

The 95% effective concentration of ropivacaine (0.30 ml/kg total, 0.15 ml/kg per side) for ultrasound-guided RSB was 0.31% in children undergoing single-incision laparoscopic surgery under general anesthesia.

Median effective dose of 0.2% ropivacaine for ultrasound-guided median nerve block in young children

OBJECTIVE

To determine the median effective dose (ED₅₀) and the 95% effective dose (ED₉₅) of 0.2% ropivacaine for ultrasound-guided lower forearm median nerve block in paediatric patients.

METHODS

Eligible children were American Society of Anesthesiologists (ASA) status I-II scheduled to have elective open surgery for trigger thumb repair. Patients were stratified into two age groups: 1- to 3-year-olds and 3- to 6-year-olds. The ED₅₀ was determined by Dixon's up-and-down method. The first patient received an ultrasound-guided median nerve block by injection of 2 mL of 0.2% ropivacaine. Each subsequent patient's dose was determined by the response of the previous patient, the doses being adjusted in intervals of 0.2 mL. In addition, the 95% effective dose (ED₉₅) was obtained using a probit regression approach. The patients' general condition, postoperative pain scores, and adverse events were recorded.

RESULTS

A total of 52 children who were scheduled to undergo open surgery for trigger thumb were included in this study: 28 in the 1- to 3-year-olds group and 24 in the 3- to 6-year-olds group. The ED₅₀ (95% confidence interval) values were 0.9 (0.44-1.36) mL in 1- to 3-year-olds and 1.4 (1.14-1.66) mL in 3- to 6-year-olds. The ED₉₅ (95% confidence interval) values were 1.5 (0.98-1.58) mL in 1- to 3-year-olds and 1.7 (1.54-1.78) mL in 3- to 6-year-olds. No adverse events occurred.

CONCLUSIONS

A single dose of ropivacaine was an effective agent for young children requiring ultrasound-guided lower forearm median nerve block in open surgery for trigger thumb. The ED₅₀ (95% confidence interval) values were 0.9 (0.44-1.36) mL in 1- to 3-year-olds and 1.4 (1.14-1.66) mL in 3- to 6-year-olds. The ED₉₅ (95% confidence interval) values were 1.5 (0.98-1.58) mL in 1- to 3-year-olds and 1.7 (1.54-1.78) mL in 3- to 6-year-olds.

Ultrasound-guided peripheral trunk block technique: A new approach gradually stepping onto the stage of clinical anesthesia

In recent years, with the continuous development and validation of new visualization, the ultrasound-guided peripheral trunk block becomes more mature and has a more extensive and broader implementation scope in clinical anesthesia. Based on this, we reviewed and summarized the literature on peripheral trunk nerve block include: paraspinal block, retrolaminar block, plane block of erect spinal muscle, transverse convex to pleural midpoint block, block of the trapezius muscle and anterior serratus muscle, anterior serratus muscle block, thoracic nerve block, abdominal transverse fascia block, type-I block of quadratus lumborum, type-II block of quadratus lumborum, type-III block of quadratus lumborum, block of the sheath of rectus abdominis. This paper reviews the ultrasound-guided peripheral trunk block technique, including development history, anatomic basis, implementation methods, advantages and disadvantages of nerve block technique, and describes the bottleneck and difficulties of nerve block technique at present.

Evaluation of Pectoral Nerve Block in Modified Radical Mastectomy: Comparison of Three Concentrations of Ropivacaine

Background

Pectoral nerve block type I (PECS I Block) and type II (PECS II Block) with ropivacaine are relatively new analgesic methods for breast-cancer surgery. We evaluated the safety and efficacy of different concentrations of ropivacaine given in the same volume for the PECS II Block in patients undergoing modified radical mastectomy (MRM).

Patients and Methods

One hundred and twenty women undergoing elective MRM who met inclusion criteria were divided randomly into four groups of 30: control group without PECS II Block and R_0.2%, R_0.3%, and R_0.4% groups, who received general anesthesia plus the PECS II Block with ropivacaine at 0.2%, 0.3%, and 0.4%, respectively, in a volume of 40 mL.

Results

The postoperative numerical rating scale (NRS) pain score at rest and active was significantly higher in the control group than that in the three ropivacaine groups (P<0.05 for all), and the postoperative NRS score in the R_0.3% group and R_0.4% group at 12, 24, and 48 h postoperatively were significantly lower than that in the R_0.2% group (P<0.05 for all); there was no significant difference between the R_0.3% group and R_0.4% group. The time when pain was first felt after MRM, the total number of complaints during 3, 6, 12, 24, and 48 h after MRM, and the total analgesic requirement (tramadol consumption) during the first 24 h postoperatively in the R_0.3% group and R_0.4% group were significantly lower than those in the control group and R_0.2% group (P<0.05 for all); there was no significant difference between the R_0.3% group and R_0.4% group.

Conclusion

A dose of 0.3% ropivacaine was the optimal concentration for a PECS II Block for patients undergoing MRM because it provided efficacious analgesia during and >48 h after MRM. Increasing the ropivacaine concentration did not improve the analgesia of the PECS II Block significantly.

Regional anesthesia to ameliorate postoperative analgesia outcomes in pediatric surgical patients: an updated systematic review of randomized controlled trials

Regional anesthesia is becoming increasingly popular among anesthesiologists in the management of postoperative analgesia following pediatric surgery. The main objective of this review was to systematically evaluate the last 5 years of randomized controlled trials on the role of regional anesthesia techniques in alleviating postoperative pain associated with various pediatric surgical procedures. Forty studies on 2,408 pediatric patients were evaluated. The majority of the articles published from 2013 to 2017 reported that the use of regional anesthesia minimized postoperative pain and reduced opioid consumption. Only a few surgical procedures (cholecystectomy, inguinal hernia repair, and non-laparoscopic major abdominal surgery) reported no significant difference in the postoperative pain relief compared with the standard anesthetic management. The growing number of randomized controlled trials in the pediatric literature is very promising; however, additional confirmation is needed to reinforce the use of specific regional anesthesia techniques to provide optimal postoperative pain relief for a few surgical procedures (reconstructive ear surgery, chest wall deformity, hypospadias, umbilical hernia, cleft palate repair) in pediatric patients. More randomized controlled trials are needed to establish regional anesthesia as an essential component of postoperative analgesia management in children.

Sequential allocation trial design in anesthesia: an introduction to methods, modeling, and clinical applications

Estimation of the dose-response curve for new anesthetic protocols typically focuses on identifying minimum effective doses. The application of a sequential experimental method is appropriate, as it minimizes sample size requirements by updating dose assignments based on information accrued from successive subjects. One approach is the up-and-down method for estimating the median effective dose in a patient population (ED₅₀ ). Designs better suited for achieving greater than 50% effectiveness, include the biased coin approach, and continual reassessment method. In this review we introduce different sequential design methods, provide examples of their use, and show through simulation how the method employed influences sample size and the accuracy of the estimated dose. Simulation studies are presented to illustrate the effects of dose parameter and stopping rule choice for up-and-down method and biased coin approach. For continual reassessment method, the effects of assumed dose-response model, prior guess, and cohort size are simulated. A binary response regression curve was fit to the data in Saidman and Eger's endtidal halothane dose-finding study to provide a dose-response curve for generating simulations. A range of options exist when designing a study using sequential allocation with biased coin approach or continual reassessment method. Method choice influences the required sample size and confidence in estimated effect. In the halothane example, up-and-down method decreases the required sample size by 20-30% when the choice of design parameters is optimal. For both up-and-down method and biased coin approach designs, greater sample sizes, arising from adjusted stopping criteria, might be required to achieve reliable estimates. The continual reassessment method is only efficient if a limited range of doses can be chosen a priori. In conclusion the up-and-down method can be more efficient than nonsequential designs for the estimation of the median dose/intervention level for a given intervention (ED₅₀ ). The biased coin approach or continual reassessment method are preferred for the estimation of higher or lower tail quantiles such as ED₉₀ or ED₁₀ . Continual reassessment method may be superior if knowledge of the dose-response relationship is available for the drug of interest.