Background: Maternal hypotension after spinal anaesthesia occurs at a high rate during caesarean delivery and can lead to adverse maternal or foetal outcomes. The aim of this study was to determine the optimal dose of spinal ropivacaine for caesarean section with or without intravenous single bolus of S-ketamine and to observe the rates of hypotension associated with both methods. Methods: Eighty women undergoing elective caesarean delivery were randomly allocated into either a ropivacaine only or ropivacaine with intravenous S-ketamine group. If the upper sensory level of the patient reached T6 and the visual analogue scale (VAS) scores remained below 3 points before delivery, the next patient had a 1/9th chance of receiving a lower dose or an 8/9th chance of receiving the same dose as the previous patient. If the patient had VAS scores of more than 2 points or needed an extra epidural rescue bolus before delivery, a higher dose was used for the next patient. The primary outcome was the successful use of spinal ropivacaine to maintain patient VAS score of < 3 points before delivery and the incidence of post-spinal hypotension in both groups. Secondary outcomes included the rates of hypotension-related symptoms and interventions, upper sensory level of anaesthesia, level of sedation, neonatal outcomes, Edinburgh Postnatal Depression Scale scores at admission and discharge, and post-operative analgesic effect. The 90% effective dose (ED90) and 95% confidence interval (95% CI) were estimated by isotonic regression. Results: The estimated ED90 of ropivacaine was 11.8 mg (95% CI: 11.7–12.7) with and 14.7 mg (95% CI: 14.6–16.0) without intravenous S-ketamine, using biased coin up-down sequential dose-finding method. The rates of hypotension and associated symptoms were significantly lower in S-ketamine group than in the ropivacaine only group. Conclusions: A spinal dose of ropivacaine 12 mg with a single intravenous 0.15 mg/kg bolus dose of S-ketamine may significantly reduce the risk of hypotension and induce sedation before delivery. This method may be used with appropriate caution for women undergoing elective caesarean delivery and at a high risk of hypotension or experiencing extreme nervousness. Trial registration: http://www.chictr.org.cn (ChiCTR2000040375; 28/11/2020).

BACKGROUND: Aortocaval compression by the gravid uterus, low baseline vasomotor tone, and spinal anesthesia-related sympathetic blockade contribute to spinal anesthesia-induced hypotension during cesarean delivery. The finger perfusion index (PI) can predict spinal hypotension by reflecting baseline vasomotor tone, but cannot directly reflect aortocaval compression by the gravid uterus. This study aimed to examine whether baseline toe PIs predict the incidence of maternal hypotension and reflect aortocaval compression by the gravid uterus during cesarean delivery under spinal anesthesia. METHODS: One hundred parturients undergoing elective cesarean delivery were enrolled. The relationship between baseline toe PI and the incidence of hypotension after induction of spinal anesthesia was quantified using area under the receiver operator curves, and results compared for the right and left toe PIs. RESULTS: The area under the receiver operator curves for left and right toe baseline PIs were 0.81 (95% confidence interval, 0.71–0.88) and 0.76 (95% confidence interval, 0.66–0.84), respectively. After induction of spinal anesthesia, the toe PIs did not change in parturients with hypotension, but increased significantly among those who did not develop hypotension. CONCLUSIONS: Our study demonstrated that baseline toe PIs were inversely associated with the incidence of postspinal hypotension during cesarean delivery. Continuous monitoring of toe PIs during induction of spinal anesthesia might help to predict the development of postspinal hypotension and reflect the aortocaval compression by the gravid uterus.

We investigated the effect of propofol on the proliferation and viability of rat embryonic neural stem cells (rENSCs) and the potential mechanisms involved. rENSCs were isolated and cultured in vitro and treated with 1, 10, or 50 μM propofol, while the control group was treated with 0.1 μM dimethyl sulfoxide. The effect of propofol on the proliferation and viability of rENSCs was examined by proliferation and apoptosis assays. Real-time polymerase chain reaction was employed to analyze the mRNA expression of checkpoint kinase 1 (Chk1) and p53 in rENSCs exposed to propofol. Immunoprecipitation assay and western blotting analysis were performed to analyze the effect of propofol on Chk1 and p53 activity. The gamma-aminobutyric acid type A (GABAA) receptor antagonist securinine was added to the rENSCs before being treated with propofol to investigate the role of the GABAA receptor in propofol-triggered effects on rENSCs. rENSCs specifically expressing nestin protein were successfully isolated and cultured for experiments. The inhibitory effect of propofol on rENSCs increased dose-dependently. The percentage of apoptotic cells increased to 11.7% and the activity of Chk1 and p53 enhanced after treatment with 50 μM propofol. However, addition of securinine abrogated propofol-induced apoptosis and activation of Chk1. The GABAA receptor mediates propofol-induced apoptosis and proliferation inhibition of rENSCs, possibly by modulating the Chk1/p53 signaling pathway.

Background: Post-spinal anesthesia hypotension during cesarean delivery is caused by decreased systemic vascular resistance due to the blockage of the autonomic nerves, which is further worsened by inferior vena cava (IVC) compression by the gravid uterus. This study aimed to assess whether peak velocity and diameter of the IVC below the xiphoid or right common femoral vein (RCFV) in the inguinal region, as measured on ultrasound, could reflect the degree of IVC compression and further identify parturients at risk of post-spinal hypotension. Methods: Fifty-six parturients who underwent elective cesarean section with spinal anesthesia were included in this study; peak velocities and anteroposterior diameters of the IVC and peak velocities and transverse diameters of the RCFV were measured using ultrasound before anesthesia. The primary outcome was the ultrasound measurements of IVC and RCFV acquired before spinal anesthesia and their association with post-spinal hypotension. Hypotension was defined as a drop in systolic arterial pressure by > 20% from the baseline. Multinomial logistic regression analysis was used to identify the association between the measurements of IVC, RCFV, and post-spinal hypotension during cesarean delivery. Receiver operating characteristic curves were used to test the abilities of the identified parameters to predict post-spinal hypotension; the areas under the curve and optimum cut-off values for the predictive parameters were calculated. Results: A longer transverse diameter of the RCFV was associated with the occurrence of post-spinal hypotension (odds ratio = 2.022, 95% confidence interval [CI] 1.261–3.243). The area under the receiver operating characteristics curve for the prediction of post-spinal hypotension was 0.759 (95% CI 0.628–0.890, P = 0.001). A transverse diameter of > 12.2 mm of the RCFV could predict post-spinal hypotension during cesarean delivery. Conclusions: A longer transverse diameter of RCFV was associated with hypotension and could predict parturients at a major risk of hypotension before anesthesia. Trial registration: This study was registered at http://www.chictr.org.cn on 16, May, 2018. No. ChiCTR1800016163.

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 (ED₉₀) and 95% confidence interval (95% CI) were estimated using isotonic regression methods. Results: The estimated ED₉₀ 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.

The optimal dose of oral midazolam with or without intranasal S-ketamine for premedication in children: a randomised, double blinded, sequential dose-finding trial Yong Bian, Siyi Zhou, Huiyan Hou, Tao Xu, Yue Huang