Adverse side effects and route of administration of opioids in combined spinal-epidural analgesia for labour: a meta-analysis of randomised trials

Side effects from epidural analgesia in laboring women and risk of cesarean delivery

BACKGROUND

Epidural analgesia may cause maternal hypotension and changes in the fetal heart rate. The implications of such side effects on the course of labor and delivery are incompletely understood.

OBJECTIVE

This study aimed to assess whether the occurrence of maternal or fetal side effects associated with labor epidural analgesia increased the risk for cesarean delivery.

STUDY DESIGN

This was a cohort study of all women who underwent epidural analgesia during labor for the period October 1, 2020 to December 31, 2020. Excluded were cases of multiples, fetal death, noncephalic presentation, and gestational age at birth <37.0 weeks. Maternal vital signs and fetal heart rate tracings for the 1 hour before and 1 hour after epidural analgesia was administered were reviewed. The occurrence of maternal hypotension, defined as a continuous variable and dichotomized into a decrease in maternal systolic blood pressure to <90 mm Hg or a drop in systolic blood pressure by >20% below the last value before epidural analgesia was administered, was related to changes in the fetal heart rate category. The principal outcome was cesarean delivery rate; binary logistic regression analysis was used to control for confounders, and mediation model analysis was used to quantify the extent to which significant variables participated in the causation pathway to cesarean delivery (SPSS version 28 was used for the analyses).

RESULTS

A total of 439 women met the study criteria. Significant adverse reactions owing to epidural occurred in 184 of 439 women (41.9%) and included severe maternal hypotension in 159 of 439 participants (36.2%) and worsening fetal heart rate category in 50 of 439 participants (11.4%). The logistic regression analysis revealed that cervical dilation at epidural (P=.03), the duration of labor after epidural (P<.001), and worsening fetal heart rate category within 60 minutes of epidural administration (P=.01) were independently associated with recourse to cesarean delivery. The mediation analysis showed that both cervical dilatation at epidural administration and worsening fetal heart rate category had significant direct and indirect effects in the pathway to cesarean delivery.

CONCLUSION

Worsening fetal heart rate category related to labor epidural independently increased the risk for cesarean delivery.

Evaluating the Pharmacokinetics of Fentanyl in the Brain Extracellular Fluid, Saliva, Urine, and Plasma of Newborns from Transplacental Exposure from Parturient Mothers Dosed with Epidural Fentanyl Utilizing PBPK Modeling

BACKGROUND AND OBJECTIVE

Fentanyl can mitigate the mother and newborn complications resulting from labor pain. However, fentanyl shows a narrow therapeutic index between its respiratory depressive and analgesic effects. Thus, prenatally acquired high fentanyl levels in the newborn brain extracellular fluid (bECF) may induce respiratory depression which requires therapeutic drug monitoring (TDM). TDM using saliva and urine in newborns can reduce the possibility of infections and distress associated with TDM using blood. The objective of this study was to develop  a physiologically based pharmacokinetic (PBPK) model to predict fentanyl concentrations in different newborn tissues due to intrauterine exposure.

METHODS

A fentanyl PBPK model in adults after intravenous and epidural administration was built, validated, and scaled to pregnancy and newborn populations. The dose that the newborn received transplacentally at birth was calculated using the pregnancy model. Then, the newborn bECF, saliva, plasma, and urine concentrations after such a dose were predicted using the newborn PBPK model.

RESULTS

After a maternal epidural dose of fentanyl 245 µg, the predicted newborn plasma and bECF levels were below the toxicity thresholds. Furthermore, the salivary threshold levels in newborns for fentanyl analgesic and respiratory depression effects were estimated to be 0.39 and 14.7-18.2 ng/ml, respectively.

CONCLUSION

The salivary TDM of fentanyl in newborns can be useful in newborns exposed to intrauterine exposure from parturient females dosed with epidural fentanyl. However, newborn-specific values of µ-opioid receptors IC50 for respiratory depression are needed.

ED90 of epidural esketamine with 0.075% ropivacaine for labor analgesia in nulliparous parturients: a prospective, randomized and dose-finding study

Background: Because it has been reported that racemic ketamine had a local anesthetic-sparing effect when used for epidural analgesia this would suggest the likelihood of a potential advantage (less pruritus) over opioid drugs. Esketamine has greater analgesic efficacy than racemic ketamine, but the optimum dosage regimen for epidural use is undetermined. The aim of this study was to determine the ED₉₀ of epidural esketamine when coadministered with 0.075% ropivacaine for labor analgesia. Methods: A total of 65 laboring nulliparous patients were enrolled in this study from 16 March 2022 to 15 October 2022. The patients were randomly assigned to receive 0, 0.25, 0.5, 0.75 or 1.0 mg/mL esketamine with 0.075% ropivacaine epidurally. An effective response to the epidural loading dose was defined as numerical rating scale pain score ≤3 at 30 min after the end of the epidural loading dose (10 mL of the ropivacaine 0.075% solution with the added esketamine). The ED₉₀ of epidural esketamine coadministered with 0.075% ropivacaine with 95% confidence intervals for labor analgesia was determined using probit regression. Secondary outcomes and side effects were recorded. Results: The estimated value of ED₉₀ with 95% CIs for epidural esketamine with 0.075% ropivacaine was 0.983 (0.704-2.468) mg/mL. The characteristics of sensory and motor block, consumption of ropivacaine per hour, duration of first or second stage, Apgar scores did not differ among the five groups. The incidence of mild dizziness in Group esketamine 1.0 mg/mL was significantly higher than that in other groups (p < 0.05). No statistical differences were found in other side effects among groups. Conclusion: The ED₉₀ value of epidural esketamine coadministered with 0.075% ropivacaine for labor analgesia in nulliparous parturients was about 1.0 mg/mL. Furthermore, our results suggested that epidural esketamine would cause dose-dependent mild dizziness especially at doses up to 1.0 mg/mL. As a single epidural additive, esketamine may not be suitable for labor analgesia. Future studies may investigate the appropriate dosage of esketamine at slightly higher concentrations of local anesthetics or larger initial volume of analgesia, or explore other potential advantages of esketamine. Clinical Trial Registration: (https://www.chictr.org.cn/bin/project/edit?pid=159764), identifier (ChiCTR2200057662).

Comparison of the incidence of fetal prolonged deceleration after induction of labor analgesia between dural puncture epidural and combined spinal epidural technique: a pilot study

BACKGROUND

Abnormal cardiotocogram (CTG) tracing may appear after induction of neuraxial labor analgesia. Non-reassuring fetal status (NRFS) indicated by severely abnormal tracings, such as prolonged deceleration (PD) or bradycardia, can necessitate immediate operative delivery. Combined spinal epidural analgesia (CSEA) is known to result in more frequent abnormal tracings than epidural analgesia (EA); however, the corresponding data related to dural puncture epidural (DPE) are unclear. We aimed to evaluate the rates of incidence of severe abnormal CTG after induction of DPE and CSEA.

METHODS

In this study of nulliparous women with full-term pregnancy, data for the DPE intervention group were prospectively collected, while those for the CSEA control group were obtained from medical records. Neuraxial analgesia was performed with cervical dilation ≤ 5 cm, administering initial epidural dosing of 15 mL of 0.125% levobupivacaine with fentanyl 2.5µg/mL for DPE, and intrathecal 0.5% bupivacaine 2.5 mg (0.5ml), fentanyl 10 µg (0.2ml), and 1.3 mL of saline for CSEA. The primary outcome was the incidence of PD, defined as a fetal heart rate reduction ≥ 15 bpm below the baseline and with a lowest value < 80 bpm, and lasting for ≥ 2 min but < 10 min (fetal heart rate < 80 bpm does not have to last for ≥ 2 min), within 90 min after induction of neuraxial labor analgesia.

RESULTS

A total of 302 patients were analyzed, with 151 in each group. The incidence of PD after DPE induction was significantly lower than that after CSEA induction (4.0% vs. 14.6%, P = 0.0015, odds ratio = 0.243, 95% confidence interval = 0.095-0.617).

CONCLUSION

DPE appears to be a safer method compared to CSEA for neuraxial labor analgesia in the early stages of labor for nulliparous women.

TRIAL REGISTRATION

UMIN-CTR: UMIN000035153 . Date registered: 01/01/2019.

Labor risk factors for fetal heart rate abnormality after combined spinal-epidural analgesia

OBJECTIVE

To explore the association between obstetric factors or outcomes and fetal heart rate (FHR) abnormalities after combined spinal-epidural analgesia (CSEA).

METHODS

Women with singleton term deliveries who received CSEA at our institution between January 1 and December 31, 2017, were analyzed using medical records. We performed a logistic regression analysis to compare factors and outcomes between cases with and without new FHR abnormalities within 1 h after CSEA.

RESULTS

Of the 393 women, 163 showed the new occurrence of FHR abnormality after CSEA. Rupture of the membrane (odds ratio [OR] 2.49; 95% confidence interval [CI] 1.52-4.09; P < 0.01) and dilatation of the cervix (OR 1.24; 95% CI 1.07-1.44; P < 0.01) were significantly associated with FHR abnormalities. There were significant differences in FHR abnormality rates between women with cervical dilatation of 2 cm or less and 3 cm or more (OR 2.20; 95% CI 1.01-4.81; P = 0.047) and 6 cm or less and 7 cm or more (OR 2.46; 95% CI 1.01-6.01; P = 0.048). FHR abnormalities were not significantly associated with cesarean delivery during labor, instrumental delivery, APGAR score below 7 at 1 or 5 min, or umbilical arterial blood gas pH less than 7.2.

CONCLUSION

Rupture of the membrane and an advanced dilated cervix were risk factors for FHR abnormality when CSEA was initiated.

Comparison between neonatal outcomes of labor and delivery with labor neuraxial analgesia and without analgesia: A propensity score-matched study

AIM

This single-center observational study aimed to investigate the association between labor neuraxial analgesia (LNA) and neonatal outcomes.

METHODS

We conducted a retrospective cohort study at a tertiary perinatal center and included all vaginal deliveries performed between November 2015 and December 2021. Obstetric and neonatal outcomes were compared between deliveries with LNA (LNA group) and without analgesia (control group). Propensity score (PS) matching was used for statistical analysis.

RESULTS

We included 2343 singleton deliveries performed in 1367 nulliparous and 976 multiparous women, in whom LNA was induced in 352 and 178 deliveries, respectively. After PS matching, the nulliparous LNA group had a significantly higher incidence of Apgar scores <7 at 1 (7.1% vs. 3.6%, p = 0.0139) and 5 min (2.3% vs. 0.7%, p = 0.0397) and meconium staining (29.8% vs. 23.2%, p = 0.0272) than the nulliparous control group. Other neonatal outcomes, including umbilical artery pH and neonatal intensive care unit admission rate, were comparable between the nulliparous LNA and control groups. No significant differences in neonatal outcomes were seen in multiparous women. Regarding fetal heart rate abnormalities, severe late deceleration (4.8% vs. 1.7%, p = 0.0036) and severe prolonged deceleration (17.0% vs. 11.9%, p = 0.0224) were more common in the nulliparous LNA group than in the nulliparous control group, and the multiparous LNA group exhibited more severe variable deceleration (21.3% vs. 14.3%, p = 0.0485) than the multiparous control group.

CONCLUSION

Our findings suggest that LNA is associated with short-term adverse neonatal and obstetric outcomes in vaginal deliveries. LNA should be performed with precautionary measures and adequate medical resources.

Plasmatic catecholamines after neuraxial labour analgesia: A randomised controlled trial comparing epidural versus combined spinal-epidural

BACKGROUND

Combined spinal-epidural technique (CSE) for labour analgesia has been associated with fetal bradycardia and uterine hypertonia when compared with epidural analgesia (EA), possibly due to a decrease in epinephrine levels following neuraxial anaesthesia. However, there are no recent studies comparing plasmatic catecholamines levels between those two techniques. This study aimed to compare CSE versus EA regarding pre- and post-analgesia catecholamines levels, uterine tone and fetal heart rate.

PATIENTS AND METHODS

Randomised clinical trial with 47 labouring patients divided in two groups (CSE and EA). Primary outcome was plasmatic catecholamine measurements before and after neuraxial block. Secondary outcomes were fetal heart rate changes, uterine hypertonia, hypotension episodes, pain relief and fetal outcomes.

RESULTS

For CSE group, the median decrease of plasmatic epinephrine was 0 pg/mL [(-) 480-(+) 41] and for norepinephrine was -21 pg/mL [(-) 2507-(+) 94]. For EA group, the median decrease for epinephrine was 0 pg/mL [(-) 326-(+) 15] and for norepinephrine was -5 pg/mL [(-) 190-(+76)]. There were no differences between groups (p = 0.96 and p = 0.63 for epinephrine and norepinephrine, respectively). There were no differences for secondary outcomes.

CONCLUSIONS

There was no evidence of a more significant decrease of catecholamines with CSE when compared with EA. Catecholamines decrease theory may not be valid for modern labour analgesia techniques.

Acupoint Injection Decreases Anesthetic Cosumption during Combined Spinal-Epidural and Patient-Controlled Epidural Labor Analgesia

OBJECTIVE

To explore if acupoint injection can improve analgesic effects or delivery outcomes in parturients who received combined spinal-epidural analgesia (CSEA) and patient-controlled epidural analgesia (PCEA) for labor analgesia.

METHODS

A total of 307 participants were prospectively collected from July 2017 to December 2019. The participants were randomized into the combined acupoint injection with CSEA plus PCEA group (AICP group, n=168) and CSEA plus PCEA group (CP group, n=139) for labor analgesia using a random number table. Both groups received CSEA plus PCEA at cervical dilation 3 cm during labor process, and parturients of the AICP group were implemented acupoint injection for which bilateral acupoint of Zusanli (ST 36) and Sanyinjiao (SP 6) were selected in addition. The primary outcome was Visual Analogue Scale (VAS) score, and the secondary outcomes were obstetric outcomes and requirement of anesthetics doses. Safety evaluations were performed after intervention.

RESULTS

The VAS scores were significantly lower in the AICP group than in the CP group at 10, 30, 60, and 120 min after labor analgesia (all P<0.05). The latent phase of the AICP group was shorter than that of the CP group (P<0.05). There were less additional anesthetics consumption, lower incidences of uterine atony, fever, pruritus and urinary retention in the AICP group than those in the CP group (all P<0.05).

CONCLUSION

Acupoint injection combined CSEA plus PCEA for labor analgesia can decrease the anesthetic consumption, improve analgesic quality, and reduce adverse reactions in the parturients. (Registration No. ChiMCTR-2000003120).

Predicting Maternal-Fetal Disposition of Fentanyl Following Intravenous and Epidural Administration Using Physiologically Based Pharmacokinetic Modeling

Fentanyl is an opioid analgesic used to treat obstetrical pain in parturient women through epidural or intravenous route, and unfortunately can also be abused by pregnant women. Fentanyl is known to cross the placental barrier, but how the route of administration and time after dosing affects maternal-fetal disposition kinetics at different stages of pregnancy is not well characterized. To address this knowledge gap, we developed a maternal-fetal physiologically based pharmacokinetic (mf-PBPK) model for fentanyl to evaluate the feasibility to predict the maternal and fetal plasma concentration-time profiles of fentanyl after various dosing regimens. As fentanyl is typically given via the epidural route to control labor pain, an epidural dosing site was developed using alfentanil as a reference drug and extrapolated to fentanyl. Fetal hepatic clearance of fentanyl was predicted from CYP3A7-mediated norfentanyl formation in fetal liver microsomes (intrinsic clearance = 0.20 ± 0.05 µl/min/mg protein). The developed mf-PBPK model successfully captured fentanyl maternal and umbilical cord concentrations after epidural dosing and was used to simulate the concentrations after intravenous dosing (in a drug abuse situation). The distribution kinetics of fentanyl were found to have a considerable impact on the time course of maternal:umbilical cord concentration ratio and on interpretation of observed data. The data show that mf-PBPK modeling can be used successfully to predict maternal disposition, transplacental distribution, and fetal exposure to fentanyl. SIGNIFICANCE STATEMENT: This study establishes the modeling framework for predicting the time course of maternal and fetal exposures of fentanyl opioids from mf-PBPK modeling. The model was validated based on fentanyl exposure data collected during labor and delivery after intravenous or epidural dosing. The results show that mf-PBPK modeling is a useful predictive tool for assessing fetal exposures to fentanyl opioid therapeutic regimens and potentially can be extended to other drugs of abuse.

Evaluation of Therapies for Peripheral and Neuraxial Opioid-induced Pruritus based on Molecular and Cellular Discoveries

Opioids are a mainstay of treatment for pain worldwide. Pruritus, a common side effect of opioids, is a patient dissatisfier that limits their use in many clinical settings. Both parenteral and neuraxial administration of opioids frequently evoke pruritus. The ability of opioids to suppress pain while causing itch continues to perplex clinicians and researchers alike. Several mechanisms have been proposed to explain how opioids can give rise to pruritus, but specific knowledge gaps perpetuate debate. This review summarizes the clinical burden of opioid-induced pruritus and emphasizes recent discoveries of peripheral and central mechanisms for opioid-induced pruritus, particularly with respect to scientific and conceptual advances in spinal cord circuitry and mast cell biology. The mechanisms and effectiveness of existing medications used for clinical management of pruritus will be evaluated, and we will highlight the emerging preclinical utility of selective κ-opioid receptor agonists, such as nalfurafine, for the management of opioid-induced pruritus.

Lower, Variable Intrathecal Opioid Doses, and the Incidence of Prolonged Fetal Heart Rate Decelerations After Combined Spinal Epidural Analgesia for Labor: A Quality Improvement Analysis

Background

Combined spinal-epidurals with low-dose intrathecal opioids and local anesthetics are commonly used to initiate labor analgesia due to the fast onset of analgesia and good patient satisfaction. Intrathecal fentanyl has been associated with fetal bradycardia, and the rate may be higher at doses of 25 mcg and above. As such, our institution limits intrathecal fentanyl doses to less than 15 mcg for labor. Prompted by a few incidents of prolonged fetal bradycardia at even these low doses, we sought to audit the side effects associated with varying low doses of intrathecal fentanyl.

Methods

After IRB approval, a retrospective review was performed on 555 labor records from May–December, 2016. All the patients received combined spinal epidurals for labor analgesia. Intrathecal medication consisted of 1 mL of 0.25% bupivacaine, and varying fentanyl doses: 2.5, 5, 10, and 15 mcg. The incidences of prolonged fetal heart rate decelerations, emergent cesarean delivery, magnitude of pain reduction, pruritus requiring treatment, and hypotension were compared.

Results

Demographic variables were equivalent between the groups. There were no differences in the rates of prolonged fetal decelerations (in order of increasing fentanyl dose: 4.4%, 2.3%, 7.6%, 3.0%, p-value = 0.11), emergent cesarean delivery, magnitude of pain reduction, pruritus, or maternal hypotension.

Conclusions

In conclusion, the rates of prolonged fetal heart rate decelerations after combined spinal epidural with intrathecal bupivacaine and fentanyl does not differ for fentanyl doses of 15 mcg and below.

Continuous Maternal Hemodynamics Monitoring at Delivery Using a Novel, Noninvasive, Wireless,PPG-Based Sensor

Objective: To evaluate continuous monitoring of maternal hemodynamics during labor and delivery utilizing an innovative, noninvasive, reflective photoplethysmography-based device. Study design: The Biobeat Monitoring Platform includes a wearable wristwatch monitor that automatically samples cardiac output (CO), blood pressure (BP), stroke volume (SV), systemic vascular resistance (SVR), heart rate (HR) every 5 s and uploads all data to a smartphone-based app and to a data cloud, enabling remote patient monitoring and analysis of data. Low-risk parturients at term, carrying singletons pregnancies, were recruited at early delivery prior to the active phase. Big data analysis of the collected data was performed using the Power BI analysis tool (Microsoft). Next, data were normalized to visual presentation using Excel Data Analysis and the regression tool. Average measurements were compared before and after rupture of membranes, epidural anesthesia, fetal delivery, and placental expulsion. Results: Eighty-one parturients entered analysis. Epidural anesthesia was associated with a slight elevation in CO (5.5 vs. 5.6, L/min, 10 min before and after EA, p < 0.05) attributed to a non-significant increase in both HR and SV. BP remained stable as of counter decrease in SVR (1361 vs. 1319 mmHg⋅min⋅mL⁻¹, 10 min before and after EA, p < 0.05). Fetal delivery was associated with a peak in CO after which it rapidly declined (6.0 vs. 7.2 vs. 6.1 L/min, 30 min before vs. point of delivery vs. after delivery, p < 0.05). The mean BP remained stable throughout delivery with a slight increase at fetal delivery (92 vs. 95 vs. 92.1 mmHg, p < 0.05), reflecting the increase in CO and decrease in SVR (1284 vs. 1112 vs. 1280 mmHg⋅min⋅mL⁻¹, p < 0.05)with delivery. Placental expulsion was associated with a second peak in CO and decrease in SVR. Conclusions: We presented a novel application of noninvasive hemodynamic maternal monitoring throughout labor and delivery for both research and clinical use.