The 90% effective dose of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia in parturients with super obesity: an up-down sequential allocation study.

PURPOSE: To determine the 90% effective dose (ED90) of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia (CSE) in parturients with super obesity (body mass index [BMI] ≥ 50 kg·m-2). METHODS: We enrolled parturients with BMI ≥ 50 kg·m-2 with term, singleton vertex pregnancies undergoing elective Cesarean delivery under CSE. An independent statistician generated the 0.75% hyperbaric bupivacaine dosing regimen in increments of 0.75 mg using a biased-coin up-down sequential allocation technique. This was combined with 15 µg fentanyl, 150 µg morphine, and normal saline to a volume of 2.05 mL. The initial and maximum doses were 9.75 mg and 12 mg, respectively. Participants, clinical team, and outcome assessors were blinded to the dose. The primary outcome was block success, defined as T6 block to pinprick within ten minutes and no intraoperative analgesic supplementation within 90 min of spinal injection. We determined the ED90 using logistic regression. RESULTS: We enrolled 45 parturients and included 42 in the analysis. All doses achieved a T6 level within ten minutes, and the primary outcome occurred in 0/1 (0%) of the 9.75-mg doses, 2/3 (67%) of the 10.5-mg doses, 21/27 (78%) of the 11.25-mg doses, and 11/11 (100%) of the 12-mg doses. The ED90 of hyperbaric bupivacaine was 11.56 mg (95% confidence interval, 11.16 to 11.99). Four parturients (9.5%) had sensory level higher than T2, but none was symptomatic or required general anesthesia. CONCLUSION: The estimated ED90 of hyperbaric bupivacaine with fentanyl and morphine in parturients with super obesity undergoing Cesarean delivery under CSE was approximately 11.5 mg. STUDY REGISTRATION: ClinicalTrials.gov (NCT03781388); first submitted 18 December 2018.

RéSUMé: OBJECTIF: Notre objectif était de déterminer la dose efficace à 90 % (DE90) de bupivacaïne hyperbare intrathécale pour l'accouchement par césarienne sous péri-rachianesthésie combinée (PRC) chez les personnes parturientes atteintes de super obésité (indice de masse corporelle [IMC] ≥ 50 kg·m−2). MéTHODE: Nous avons recruté des personnes parturientes ayant un IMC ≥ 50 kg·m−2 présentant des grossesses uniques à terme, en présentation céphalique et bénéficiant d'un accouchement par césarienne programmée sous PRC. Un·e statisticien·ne indépendant·e a généré le schéma posologique de bupivacaïne hyperbare à 0,75 % par incréments de 0,75 mg à l'aide d'une technique d'allocation séquentielle en escalier. La bupivacaïne a été combinée à 15 µg de fentanyl, 150 µg de morphine et à une solution physiologique salée jusqu'à un volume de 2,05 mL. Les doses initiale et maximale étaient respectivement de 9,75 mg et 12 mg. Les participant·es, l'équipe clinique et les personnes évaluant les résultats n'avaient pas connaissance de la dose. Le critère d'évaluation principal était la réussite du bloc, définie comme un bloc à T6 à la piqûre dans les dix minutes et aucune supplémentation analgésique peropératoire dans les 90 minutes suivant l'injection rachidienne. Nous avons déterminé la DE90 à l'aide d'une méthode de régression logistique. RéSULTATS: Nous avons recruté 45 personnes parturientes et en avons inclus 42 dans l'analyse. Toutes les doses ont atteint le niveau T6 en dix minutes, et le critère d'évaluation principal a été obtenu pour 0/1 (0 %) des doses de 9,75 mg, 2/3 (67 %) des doses de 10,5 mg, 21/27 (78 %) des doses de 11,25 mg et 11/11 (100 %) des doses de 12 mg. La DE90 de bupivacaïne hyperbare était de 11,56 mg (intervalle de confiance à 95 %, 11,16 à 11,99). Quatre personnes parturientes (9,5 %) ont affiché un niveau sensoriel supérieur à T2, mais aucune n'était symptomatique ni n'a nécessité d'anesthésie générale. CONCLUSION: La DE90 estimée de bupivacaïne hyperbare avec fentanyl et morphine chez les personnes parturientes hyperobèses bénéficiant d'une césarienne sous PRC était d'environ 11,5 mg. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT03781388); soumis pour la première fois le 18 décembre 2018.

ED 90 of Intrathecal Chloroprocaine With Fentanyl for Prophylactic Cervical Cerclage: A Sequential Allocation Biased-Coin Design.

BACKGROUND: Chloroprocaine is a short-acting local anesthetic that has been used for spinal anesthesia in outpatient surgery. There is limited experience with spinal chloroprocaine for prophylactic cervical cerclage placement. We sought to determine the effective dose of intrathecal chloroprocaine for 90% of patients (ED90) undergoing prophylactic cervical cerclage placement. We hypothesized that the ED90 of intrathecal chloroprocaine when combined with 10-ug fentanyl would be between 33 and 54 mg. METHODS: In this prospective 2-center double-blinded study, we enrolled women undergoing prophylactic cervical cerclage placement under combined spinal-epidural anesthesia. A predetermined dose of intrathecal 3% chloroprocaine with fentanyl 10 ug was administered. The initial dose was 45-mg intrathecal chloroprocaine. Subsequent dose adjustments were determined based on the response of the previous subject using an up-down sequential allocation with a biased-coin design. A dose was considered effective if at least a T12 block was achieved, and there was no requirement for epidural activation or intraoperative analgesic supplementation during the procedure. The primary outcome was the ED90 of intrathecal chloroprocaine with fentanyl 10 ug. Secondary outcomes included duration of surgery, anesthetic side effects, time to resolution of motor and sensory block, time to achieve recovery room discharge criteria, and patient satisfaction with anesthetic care. Isotonic regression was used to estimate the ED90. RESULTS: Forty-seven patients were enrolled into the study. Two patients were excluded (1 protocol violation and 1 failed block). In total, 45 patients completed the study. The estimated ED90 (95% confidence interval) for intrathecal chloroprocaine combined with fentanyl 10 ug was 49.5 mg (45.0-50.1 mg). The median (interquartile range [IQR]) duration of surgery was 15 (10-24) minutes. Resolution of the motor (Bromage 0) and sensory block took a median time of 60 (45-90) minutes and 90 (75-105) minutes, respectively. The median time to achieve recovery room discharge criteria was 150 (139-186) minutes. Satisfaction with anesthetic management was high in all patients. There were no reports of postdural puncture headache or transient neurological symptoms postoperatively. CONCLUSIONS: The ED90 of intrathecal chloroprocaine combined with fentanyl 10 ug was 49.5 mg. Intrathecal chloroprocaine was associated with rapid block recovery and high patient satisfaction, which makes it well suited for outpatient obstetric procedures.

Quality of Labor Analgesia with Dural Puncture Epidural versus Standard Epidural Technique in Obese Parturients: A Double-blind Randomized Controlled Study.

BACKGROUND: The dural puncture epidural technique may improve analgesia quality by confirming midline placement and increasing intrathecal translocation of epidural medications. This would be advantageous in obese parturients with increased risk of block failure. This study hypothesizes that quality of labor analgesia will be improved with dural puncture epidural compared to standard epidural technique in obese parturients. METHODS: Term parturients with body mass index greater than or equal to 35 kg · m-2, cervical dilation of 2 to 7 cm, and pain score of greater than 4 (where 0 indicates no pain and 10 indicates the worst pain imaginable) were randomized to dural puncture epidural (using 25-gauge Whitacre needle) or standard epidural techniques. Analgesia was initiated with 15 ml of 0.1% ropivacaine with 2 µg · ml-1 fentanyl, followed by programed intermittent boluses (6 ml every 45 min), with patient-controlled epidural analgesia. Parturients were blinded to group allocation. The data were collected by blinded investigators every 3 min for 30 min and then every 2 h until delivery. The primary outcome was a composite of (1) asymmetrical block, (2) epidural top-ups, (3) catheter adjustments, (4) catheter replacement, and (5) failed conversion to regional anesthesia for cesarean delivery. Secondary outcomes included time to a pain score of 1 or less, sensory levels at 30 min, motor block, maximum pain score, patient-controlled epidural analgesia use, epidural medication consumption, duration of second stage of labor, delivery mode, fetal heart tones changes, Apgar scores, maternal adverse events, and satisfaction with analgesia. RESULTS: Of 141 parturients randomized, 66 per group were included in the analysis. There were no statistically or clinically significant differences between the dural puncture epidural and standard epidural groups in the primary composite outcome (34 of 66, 52% vs. 32 of 66, 49%; odds ratio, 1.1 [0.5 to 2.4]; P = 0.766), its individual components, or any of the secondary outcomes. CONCLUSIONS: A lack of differences in quality of labor analgesia between the two techniques in this study does not support routine use of the dural puncture epidural technique in obese parturients.

ER Alpha Rapid Signaling Is Required for Estrogen Induced Proliferation and Migration of Vascular Endothelial Cells.

Estrogen promotes the proliferation and migration of vascular endothelial cells (ECs), which likely underlies its ability to accelerate re-endothelialization and reduce adverse remodeling after vascular injury. In previous studies, we have shown that the protective effects of E2 (the active endogenous form of estrogen) in vascular injury require the estrogen receptor alpha (ERα). ERα transduces the effects of estrogen via a classical DNA binding, "genomic" signaling pathway and via a more recently-described "rapid" signaling pathway that is mediated by a subset of ERα localized to the cell membrane. However, which of these pathways mediates the effects of estrogen on endothelial cells is poorly understood. Here we identify a triple point mutant version of ERα (KRR ERα) that is specifically defective in rapid signaling, but is competent to regulate transcription through the "genomic" pathway. We find that in ECs expressing wild type ERα, E2 regulates many genes involved in cell migration and proliferation, promotes EC migration and proliferation, and also blocks the adhesion of monocytes to ECs. ECs expressing KRR mutant ERα, however, lack all of these responses. These observations establish KRR ERα as a novel tool that could greatly facilitate future studies into the vascular and non-vascular functions of ERα rapid signaling. Further, they support that rapid signaling through ERα is essential for many of the transcriptional and physiological responses of ECs to E2, and that ERα rapid signaling in ECs, in vivo, may be critical for the vasculoprotective and anti-inflammatory effects of estrogen.