Minimum effective fluid volume of colloid to prevent hypotension during caesarean section under spinal anesthesia using a prophylactic phenylephrine infusion: An up-down sequential allocation study

Optimum dose of spinal ropivacaine with or without single intravenous bolus of S-ketamine during elective cesarean delivery: a randomized, double-blind, sequential dose-finding study

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).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04229-y.

Comparing the Effects of Pre-loading with Gelatine 4% Plasma Volume Expander and 6% Hydroxyethyl Starch Solution Before Spinal Anaesthesia for Lower Limb Orthopaedic Surgery

BACKGROUND

Hypotension is a common complication following spinal anaesthesia. The administration of intravenous fluids prior to spinal anaesthesia, known as pre-loading, has been used to offset the hypotension effect; however, the ideal fluid for pre-loading is still a matter of debate. The objective of this study was to compare the effects of Gelaspan 4% and Volulyte 6% as pre-loading fluids.

METHODS

A total of 93 patients with American Society of Anaesthesiologists (ASA) physical status I or II having lower limb orthopaedic surgery under spinal anaesthesia were randomised into two groups that received either Volulyte (n = 47) or Gelaspan (n = 46). Before the spinal anaesthesia, these patients were pre-loaded with 500 mL of the fluid of their respective group. Blood samples were taken before pre-loading and again after spinal anaesthesia and sent for venous blood gas and electrolyte level measurement. Baseline and intraoperative records of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and the requirement of ephedrine to treat hypotension were also recorded.

RESULTS

Both fluids could not prevent significant reductions in SBP (P = 0.011), DBP (P = 0.002) and MAP (P = 0.001). There was also significant reduction in HR over time (P < 0.001). There was no significant difference in terms of ephedrine usage between both groups. Neither Volulyte 6% nor Gelaspan 4% caused significant changes in acid-base status.

CONCLUSION

The use of 500 mL of either Gelaspan 4% or Volulyte 6% as pre-loading fluids did not significantly prevent the incidence of post-spinal anaesthesia hypotension following orthopaedic lower limb surgery; however, both were useful in the maintenance normal acid-base balance.

Effects of continuous infusion of phenylephrine vs. norepinephrine on parturients and fetuses under LiDCOrapid monitoring: a randomized, double-blind, placebo-controlled study

Background

Hypotension following spinal anesthesia (SA) during cesarean delivery (CD) occurs commonly and is related with maternal and fetal complications. Norepinephrine infusion is increasingly used for prevention of post-SA hypotension; however, its effects as compared to the traditional phenylephrine infusion remain unclear. This study aimed to compare the effects of phenylephrine and norepinephrine administered as continuous infusion during elective CD on maternal hemodynamic parameters and maternal and fetal outcomes.

Methods

This prospective, single-center, randomized, controlled study included 238 consecutive term parturients who underwent CD from February 2019 to October 2019. They were randomized to receive continuous infusion of 0.25 μg/kg/min phenylephrine, 0.05 μg/kg/min norepinephrine, or placebo. Hemodynamic monitoring was performed at 10 time points using LiDCOrapid. We analyzed umbilical vein (UV), umbilical artery (UA), and peripheral vein (PV) blood gas indexes and recorded intraoperative complications.

Results

In phenylephrine group, the systolic blood pressure (SBP) remain during the whole operation. Compared to the control group, phenylephrine, but not norepinephrine, significantly increased the systemic vascular resistance (SVR) to counteract the SA-induced vasodilatation, 3 min following norepinephrine/phenylephrine/LR administration (T4): 957.4 ± 590.3 vs 590.1 ± 273.7 (P < 0.000001); 5 min following norepinephrine/phenylephrine/LR administration (T5): 1104 ± 468.0 vs 789.4 ± 376.2 (P = 0.000002). at the time of incision (T6): 1084 ± 524.8 vs 825.2 ± 428.6 (P = 0.000188). Parturients in the phenylephrine group had significantly lower UV (1.91 ± 0.43) (P = 0.0003) and UA (2.05 ± 0.61) (P = 0.0038) lactate level compared to controls. Moreover, the UV pH value was higher in the phenylephrine than in the control group7.37 ± 0.03(P = 0.0013). Parturients had lower incidence of nausea, tachycardia, hypotension in phenylephrine group.

Conclusions

In this dataset, continuous phenylephrine infusion reduced the incidence of SA-induced hypotension, ameliorated SVR, while decreasing overall maternal complications. Phenylephrine infusions are considered the better choice during CD because of the significant benefit to the fetus.

Trial registration

Clinicaltrial.gov Registry, NCT03833895, Registered on 1 February 2019.

Dexmedetomidine as an adjuvant for single spinal anesthesia in patients undergoing cesarean section: a system review and meta-analysis

OBJECTIVE

Previous studies reported the effect of dexmedetomidine on intrathecal anesthesia. In this review, we explored the impact of dexmedetomidine as an adjunct for lumbar anesthesia in patients undergoing cesarean section.

METHODS

Two authors searched eligible random controlled trials in electronic databases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, the Chinese BioMedical database, Chinese Scientific Journal Database, and the Wanfang database.

RESULTS

Ten trials comprising 970 patients were included in this review. Intrathecal dexmedetomidine significantly reduced the onset time of sensory block (standardized mean difference (SMD), -1.50, 95% confidence interval (CI) -2.15, -0.85, I² = 92%) and motor block (SMD -0.77, 95% CI -1.50, -0.49, I² = 60%) and prolonged the block duration time (sensory block: SMD 2.02, 95% CI 1.29, 2.74, I² = 93%; motor block: SMD 1.90, 95% CI 1.07, 2.74, I² = 94%). Patients who received dexmedetomidine showed a lower incidence of shivering. No significant difference was reported for the neonatal Apgar score and other complications.

CONCLUSION

The use of intrathecal dexmedetomidine during cesarean section can shorten the onset time of spinal anesthesia and enhance the effect of local anesthetic. It has no significant impact on neonates and there were no other adverse events.

Recommendations for the use of ECT in pregnancy: literature review and proposed clinical protocol

Psychiatric disorders are common in pregnancy, affecting 15-29% of pregnant women. Untreated depression has negative health consequences for mother and fetus. Electroconvulsive therapy (ECT) is an effective option for the treatment of severe depression, high suicide risk, catatonia, medication-resistant illness, psychotic agitation, severe physical decline, and other life-threatening conditions. To our knowledge, however, there is no literature that consolidates all the evidence on maternal and fetal risks associated with untreated depression, medications, and ECT then translating it into one cohesive protocol that could serve as a management guide and a source of reassurance to health-care providers involved in such practice. Hoping to facilitate ECT access to perinatal patients, the authors combined their multidisciplinary clinical experience (in perinatal psychiatry, neuropsychiatry and neuromodulation, and anesthesiology) at three different centers in the USA (Brigham and Women's Hospital/Harvard Medical School, The University of Chicago, and Brown University) with a careful and critical literature review and propose guidelines for the administration of ECT in pregnancy. A comprehensive review of the relevant literature regarding both ECT and psychotropic medications in pregnancy was performed, including meta-analyses of randomized controlled trials published in general medicine, anesthesiology, psychiatry, and obstetrics journals and guidelines. The indication and appropriateness of ECT in pregnancy must be carefully weighed against the risks of untreated maternal illness and those of alternative treatment options. The safety of ECT in pregnancy has been documented over the last 50 years. The adverse effects in pregnancy are similar to the risks of ECT in any individual. The most common risk to the mother is premature contractions and preterm labor, which occur infrequently and are not clearly caused by ECT. The rates of miscarriages were not significantly different from that of the general population. There have been no associations of ECT with congenital anomalies, either morphologic or behavioral, and no neurocognitive disturbances in the child. ECT is a reasonably safe and effective treatment alternative for management of many psychiatric disorders in pregnant patients. The authors provide recommendations for treatment modifications in pregnancy-based physiologic changes that occur during that period and consolidate them into a protocol that can assist clinicians in improving access and safety of ECT for pregnant patients.

The Effects of Pre-Spinal Anesthesia Administration of Crystalloid and Colloid Solutions on Hypotension in Elective Cesarean Section

Background

Spinal anesthesia is an appropriate alternative for general anesthesia in many operations, particularly in cesarean section. However, the induced hypotension is the main drawback of this method. Therefore, the current study aimed at comparing the effects of crystalloid and colloid solutions used as the preload on the post-spinal hypotension and its complications in females who are candidate for elective cesarean section.

Methods

The current randomized, controlled, double-blind study was conducted on the female candidate of elective cesarean section (n = 96; age range: 20 to 40 years). The patients were in their 37 to 42 weeks of gestational age during the experiments. The systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) variation, amount of injected ephedrine during surgery, Apgar score at birth, total solution infused after spinal anesthesia, urine output, nausea, and vomiting were comparatively assessed between the two groups.

Results

The percentages of reduction in SBP and DBP variables in the crystalloid solution were higher than those of the colloid group and the differences were statistically significant (P = 0.042 and P = 0.008, respectively). Average percentage of HR changes was more significant in the crystalloid than the colloid group (P = 0.032). In contrary, administration of the two types of solutions did not result in significant differences in the Apgar scores. The prevalence of nausea and vomiting in the colloid group subjects was lower than those of the crystalloid solution group; however, the differences were not significant.

Conclusions

The current study findings recommend colloid solution to prevent hemodynamic instability after spinal anesthesia. However, the costs and availability of the solution and recommendation of anesthesiologist should be considered. Conduction of further clinical trials with larger sample sizes is recommended.