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Objective·To explore the optimal dose of ropivacaine for elective cesarean section under spinal anesthesia combined with a single low-dose of intravenous S-ketamine, and observe the rates of hypotension associated with this method. Methods· Forty eligible women were included in the study for spinal anesthesia block combined with intravenous low-dose S-ketamine (0.15 mg/kg). The first patient received a 12 mg spinal anesthesia dose of ropivacaine. If the upper sensory block level of the patient was not lower than the sixth thoracic vertebra (T6) and visual analog scale (VAS) score was ≤2 before delivery, the next patient had 1/9 chance of receiving a lower dose or 8/9 chance of receiving the same dose of ropivacaine as the previous patient. If the patient had VAS score>2 or needed an extra epidural analgesics before delivery, a higher dose of ropivacaine was used for the next patient. The primary outcome was whether the effect of spina anesthesia was accurate, that is, the amount of ropivacaine to maintain patients' VAS score ≤2 before delivery, and the incidence of post-spinal anesthesia hypotension. Secondary outcomes mainly included the rate of hypotension-related symptoms and drug interventions, upper sensory block level of anesthesia, level of sedation (Ramsay sedation scale was used as the evaluation standard) and neonatal outcomes. 90% effective dose (ED90) and 95% confidence interval (95% CI) of ropivacaine were estimated by Isotonic regression. Results·In combination with low-dose S-ketamine, the ED90 of ropivacaine for cesarean section spinal anesthesia was 11.8 mg (95%CI 11.7- 12.7). The incidence of hypotension and hypoxemia of forty parturients was 5.0% (2 cases) and 2.5% (1 case), respectively, and there was no bradycardia occurring. All parturients did not use phenylephrine injection as a remedy, and there was no adverse reactions related to hypotension occurring (dyspnea, nausea, vomiting, shiver and blurred vision). There was no reflux and aspiration occurring. Only one parturient before delivery had a Ramsay sedation score of 2 (awake, quiet and cooperative), and the rest scored 3 (sleepy but respond quickly to instruction). At 5 min after delivery, according to the Ramsay sedation scale, 32 parturients were 2 scores, and 8 parturients were 3 scores. At the end of the operation, the Ramsay sedation scale of all parturients was 2 scores. During the cesarean section, the incidence of visceral traction pain, nightmare and dizziness of patients was 7.5%, 62.5% and 52.5%, respectively. In addition, the Apgar scores of 40 newborns at 1 min and 5 min after birth were all 10, and the umbilical vein blood gas analysis showed that the pH was (7.37±0.03). Conclusion·Combined with a intravenous single low-dose of S-ketamine during spinal anesthesia for elective cesarean section, the ED90 of ropivacaine is 11.8 mg, and this method can effectively reduce the incidence of hypotension. [ABSTRACT FROM AUTHOR]

Objective * To determine the optimal intravenous norepinephrine bolus dose needed to prevent hypotension after combined spinal and epidural anesthesia in 90% of women during elective cesarean delivery. Methods * Forty women undergoing elective cesarean delivery were allocated into this double-blinded, prospective, and sequential dose-finding study using biased coin design sequential method. The primary outcome was the successful use of the norepinephrine bolus dose to maintain systolic blood pressure above 80% of the baseline until delivery. Secondary outcomes included dizziness, breathlessness, nausea, vomiting, bradycardia, secondary hypertension and supplemental use of atropine or norepinephrine of the women, as well as 1 min and 5 min Apgar scores of the newborns. The 90% effective dose (ED90) and its 95%CI were estimated using Isotonic regression methods. Results * The estimated ED90 intravenous bolus dose of norepinephrine was [10.85 (95%CI 9.20-11.67)] µg to prevent hypotension after combined spinal and epidural anesthesia during cesarean delivery. The occurrence rates of dizziness, breathlessness, and nausea were 2.5%, 7.5% and 10.0%, respectively. The occurrence rate of additional rescue norepinephrine boluses was 5.0%. No vomiting, bradycardia, secondary hypertension and supplemental use of atropine appeared. Apgar scores of all newborns at 1 min and 5 min were 10. Conclusion * An intravenous norepinephrine bolus dose of 11 µg is recommended to prevent hypotension after combined spinal and epidural anesthesia during cesarean delivery for clinical practice. [ABSTRACT FROM AUTHOR]

Euphorbia dentata es una maleza anual, de ciclo primaveral estival que está presente en el 85% del área agrícola del partido de Azul, provincia de Buenos Aires, Argentina. Estudios en campo fueron conducidos durante dos años a fin de realizar ajustes de dosis y momentos de aplicación que permitan lograr una alta eficacia de control de E. dentata con glifosato y estudiar el uso de distintas concentraciones de un surfactante, para lograr resultados más predecibles en aplicaciones a campo. Se realizó un ensayo que consistió en la aplicación de dosis crecientes del herbicida en dos estados fenológicos de la maleza y con los datos se establecieron relaciones dosis respuesta, se ajustaron ecuaciones de regresión lineal y se determinaron las dosis de glifosato necesarias para lograr un 90% de control para cada estado fenológico de la maleza. Otro ensayo fue conducido para determinar la influencia del agregado de un surfactante en interacción con la dosis y el estado de la maleza. Se observó una dependencia de la eficacia de control de glifosato respecto del estado fenológico. La adición del surfactante a la solución de aspersión mejoró, en general la eficacia obtenida por las dosis de glifosato, detectándose una mayor influencia en los tratamientos realizados en estados fenológicos avanzados.Euphorbia dentata is an annual, spring-summer weed present in 85% of the agricultural land of the District of Azul, province of Buenos Aires, Argentina. Field studies were conducted during two years with the aim of (i) adjusting the dose and time of application that would achieve an efficient control of E. dentata with glyphosate and (ii) studying the use of different concentrations of surfactant to achieve more predictable field results. To address aim (i), a trial consisting in applying increasing doses of the herbicide was carried out in two phenological stages of the weed. Based on the data obtained, rate-response relationships were established, linear regression equations were derived and the glyphosate rate required to achieve 90% control for each phenological stage of the weed was determined. To address aim (ii), a second trial was conducted to determine the influence of adding a surfactant on the interaction between dose and weed stage. Glyphosate control efficacy was found to be dependent on the phenological stage of the weed. Surfactant addition to the aspersion solution improved the overall efficacy of the glyphosate dose applied, with a greater influence being detected in the treatments carried out at more advanced phenological stages tested.

Background: Remimazolam besylate for injection is a novel benzodiazepine. Reasonable selection and proper application of anesthetics is critical for patients. This study aims to determine the 90% effective dose (ED90) of remimazolam besylate for anesthesia induction in patients undergoing painless colonoscopy., Methods: A dose-response study was carried out in 112 patients undergoing painless colonoscopy between December 2020 and January 2021. The initial dose of remimazolam was 7.5 mg. The anesthesiologist assessed whether the depth of sedation was satisfactory according to the Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scale. If the MOAA/S score of one patient was >1 point, the loading dose for the next patient was increased by 2.5 mg. If the MOAA/S score was ≤1 point, the current dose was maintained or reduced by 2.5 mg for the next patient according to a 9:1 biased coin design. The ED90 of remimazolam besylate for anesthesia induction for painless colonoscopy was calculated. The adverse events and complications of remimazolam besylate were recorded., Results: When the drug concentration was 1 mg/mL and the infusion rate was 1,000 mL/h, the ED90 of remimazolam besylate for painless colonoscopy was 11.43 mg [95% confidence interval (CI): 9.85-13.02 mg]., Conclusions: A loading dose of 12 mg remimazolam besylate for healthy adult patients undergoing painless colonoscopy can safely, effectively, and quickly induce patients to fall asleep and shorten the anesthesia induction time.

Background: Oral administration of midazolam syrup is one of the most favorable methods of premedication, the optimal dose of midazolam and midazolam with S-ketamine for preschool children has not been determined. This prospective, double-blind, randomized, sequential dose-finding study was designed to estimate the 90% effective doses of oral midazolam with and without intranasal S-ketamine in a grade III child medical center., Methods: Eighty successive children were recruited and randomly allocated to midazolam group and midazolam with S-ketamine group. The initial oral doses of midazolam were 0.25 mg/kg in both groups, and the dose of midazolam for the next child was based on the response of the preceding child as the biased coin up-and-down designed. The primary outcome was parental separation anxiety score = 1 throughout the period of transferring from premedication center to the operation room 30 min after premedication. Secondary outcomes were the preoperative and post-operative observations. Finally, the 90% effective dose and 95% confidence intervals were estimated by isotonic regression., Results: The 90% effective dose of oral midazolam or oral midazolam with intranasal S-ketamine was 0.461 mg/kg (95% confidence interval: 0.425-0.488) and 0.253 mg/kg (95% confidence interval: 0.242-0.278), respectively. Oral midazolam with intranasal S-ketamine was quicker onset (8.9±3.8 vs. 19.7±7.4 min, P<0.001), had less incidence of behavioral changes (7.5% vs. 32.5%, P=0.010) and faster recovery (21.6±14.1 vs. 31.6±13.5 min, P=0.002) than solely oral midazolam., Conclusions: A suggestion of oral midazolam 0.3 mg/kg with intranasal small dose of S-ketamine could be used as premedication for preschool children., Trial Registration: Chinese Clinical Trial Registry., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/tp-21-247). The authors have no conflicts of interest to declare., (2021 Translational Pediatrics. All rights reserved.)

Background: As a relatively new drug in obstetrical anesthesia, norepinephrine is less likely to induce bradycardia and decrease cardiac output, which makes it a potential alternative to phenylephrine. The purpose of this study was to determine the optimal norepinephrine bolus dose needed to either prevent or reverse hypotension after the use of combined spinal and epidural (CSE) anesthesia in 90% of women during elective cesarean delivery (CD)., Methods: Eighty women undergoing elective CD were randomly allocated into either a prophylactic group or a rescue group in this dose finding study. If the women's systolic blood pressure (SBP) was maintained above 80% of their baseline, the next patient had an 8/9 th chance of receiving the same dose or a 1/9 th chance of receiving a lower dose. If the patient's SBP was not maintained, a higher dose was used for next patient. The primary outcome was the successful use of the norepinephrine bolus dose to maintain SBP above 80% of the baseline until after delivery. Secondary outcomes included nausea, vomiting, breathlessness, dizziness, hypertension, bradycardia due to hypotension and supplemental use of atropine and norepinephrine, upper sensory level of anesthesia, umbilical vein (UV) blood gases, and 1- and 5-minute Apgar scores. The 90% effective dose (ED 90 ) and 95% confidence interval (95% CI) were estimated using isotonic regression methods., Results: The estimated ED 90 of the norepinephrine prophylactic bolus was 10.85 µg (95% CI, 9.20-11.67 µg) and that of the norepinephrine rescue bolus was 12.3 µg (95% CI, 10.0-12.8 µg) using isotonic regression methods., Conclusions: For norepinephrine, either a prophylactic bolus dose of 11 µg or a rescue bolus dose of 12 µg was recommended for clinical practices., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Annals of Translational Medicine. All rights reserved.)