Predictors of breakthrough pain during labor epidural analgesia

A randomized double-blinded study assessing the dose-response of ropivacaine with dexmedetomidine for maintenance of labor with epidural analgesia in nulliparous parturients

Background: The combination of ropivacaine and dexmedetomidine has been used as an epidural analgesic for inducing labor. However, there is limited data regarding the administration of epidural analgesia for labor maintenance, hence, this study aimed to determine the optimum concentration through dose-response curves of ropivacaine plus dexmedetomidine, which could be used along with the Programmed Intermittent Epidural Bolus (PIEB) technique. Methods: One hundred parturients were randomized into 4 groups who were administered four different doses of ropivacaine (dexmedetomidine at 0.4 μg mL-1): 0.04%, 0.06%, 0.08%, and 0.1%. The primary outcome that was determined included the proportion of patients experiencing breakthrough pain during their 1st stage of labor. Breakthrough pain was described as a visual analog scale [VAS] score of >30 mm, requiring supplemental epidural analgesia after the administration of at least one patient-controlled bolus. The effective concentration of analgesia that was used for labor maintenance in 50% (EC50) and 90% (EC90) of patients were calculated with the help of probit regression. Secondary outcomes included epidural block characteristics, side effects, neonatal outcomes, and patient satisfaction. Results: The results indicated that the proportion of patients without breakthrough pain was 45% (10/22), 55% (12/22), 67% (16/24), and 87% (20/23) for 0.04%, 0.06%, 0.08%, and 0.10% doses of the analgesic that were administered, respectively. The EC50 value was 0.051% (95% confidence interval [CI], 0.011%-0.065%) while the EC90 value was recorded to be 0.117% (95% CI, 0.094%-0.212%). Side effects were similar among groups. Conclusion: A ropivacaine dose of 0.117% can be used as epidural analgesia for maintaining the 1st stage of labor when it was combined with dexmedetomidine (0.4 μg mL-1) and the PIEB technique. Clinical Trial Register: https://www.chictr.org.cn/index.aspx, identifier ChiCTR2200059557.

A randomized comparison of epidural, dural puncture epidural, and combined spinal-epidural without intrathecal opioids for labor analgesia

Background and Aims

Dural puncture epidural (DPE) has been shown to improve labor analgesia over epidural (EPL), with fewer side effects than a combined spinal-epidural (CSE). However, there is some debate regarding the superiority of DPE over EPL and CSE. Therefore, we aimed to compare the effects of EPL, DPE, and CSE without intrathecal opioids on the epidural local anesthetic (LA) consumption and occurrence of side effects in early labor.

Material and Methods

We randomly assigned parturient to one of the 3 groups; EPL, DPE, or CSE. EPL and DPE groups received a 10 mL loading dose of 0.1% bupivacaine with fentanyl 2 μg/mL. CSE group received intrathecal 2.5 mg bupivacaine (without opioids). Labor analgesia was maintained in all patients via patient-controlled epidural analgesia (PCEA). The primary outcome was the mean hourly consumption of epidural LA.

Results

The mean hourly consumption of epidural LA anesthetic was significantly lower in CSE (9.55 mL), compared with the EPL (11 mL), and DPE (10.5 mL), P < 0.01; but no significant difference was seen between EPL and DPE. Compared with EPL and DPE, CSE achieved faster time to complete analgesia defined as a numeric rating pain scale (NRPS) ≤1 and sensory block, lower NRPS in the first hour and higher frequencies of complete analgesia. There were no differences between groups in terms of physician top-up boluses, the occurrence of side-effects, mode of delivery, Apgar scores, and maternal satisfaction.

Conclusion

Compared with EPL and DPE, CSE without intrathecal opioids, had a less epidural LA consumption, faster onset of analgesia, with no difference in the incidence of side effects.

Trial Registration

This study was registered at www.clinicaltrials.gov (NCT03980951).

The relationship between resited epidural catheters after secondary epidural catheter failure and vaginal delivery: A retrospective case-control study

BACKGROUND

There are cases where epidural analgesia is initially effective but subsequently fails and needs to be resited. We evaluated the rate of normal vaginal delivery and operative delivery among parturients who had resited epidurals compared to parturients with epidurals that were not resited.

METHODS

A retrospective electronic medical review of parturients with a singleton gestation attempting normal vaginal delivery under epidural analgesia between the years 2012-2016 was conducted. Resited epidurals were defined as epidurals that were considered effective but subsequently removed and reinserted. For each resited epidural, two previous and two consecutive deliveries of parturients with normally functioning epidural catheter inserted by the same anesthesiologist were matched controls (non-resited epidurals).

RESULTS

There were 35,984 attempted vaginal deliveries with 118 resited epidurals and 472 non-resited epidurals. When adjusted for nulliparity, oxytocin administration, sex and weight of the baby, and maternal BMI, labor epidural catheter replacement was not associated with need for instrumental or caesarean delivery, (OR 1.5, 95% CI 0.91-2.49, P = .11).

CONCLUSIONS

Need for labor epidural catheter replacement does not appear to be associated with need for operative delivery based on this single-centre cohort analysis.

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.

Association of Pain Catastrophizing with Postnatal Depressive States in Nulliparous Parturients: A Prospective Study

PURPOSE

Postnatal depression (PND) is associated with maternal morbidity and socioeconomic burden. Recent studies have shown an association between pain catastrophizing, increased labor pain, and subsequent adverse postnatal adjustment; however, little is known on its role in PND development. We aimed to investigate the association between pain catastrophizing and probable PND.

METHODS

Parturients planning to undergo epidural labor analgesia were recruited. Predelivery questionnaires, including the Pain Catastrophizing Scale (PCS) and Edinburgh Postnatal Depression Scale (EPDS), were administered during early labor. A phone survey at 5- 9 weeks postdelivery was conducted to determine postdelivery EPDS and Spielberger's State-Trait-Anxiety Inventory scores. The primary outcome was a binary variable of postdelivery EPDS with cutoff of ≥10, whereas the secondary outcome was a continuous variable on increases in EPDS score.

RESULTS

Probable PND (EPDS ≥10) occurred in 10.5% (95% CI 8.0%-13.5%, 55 of 525) of women who underwent epidural labor analgesia. We found that high pain catastrophizing (PCS ≥25) was associated with increased postdelivery EPDS scores (adjusted β estimate 0.36, 95% CI 0.15-0.57; p=0.0008), but did not meet significance for increased risk of probable PND (p=0.1770). Additionally, presence of breakthrough pain during epidural analgesia (adjusted β estimate 0.24, 95% CI 0.02-0.46; p=0.0306) and lower BMI at term (adjusted β estimate -0.04, 95% CI -0.07 to -0.01; p=0.0055) were associated with increased postdelivery EPDS scores.

CONCLUSION

No significant association was found between high pain catastrophizing and probable PND; however, high predelivery pain catastrophizing, presence of breakthrough pain during epidural analgesia, and lower BMI at term were associated with increased postdelivery EPDS scores. Further research will be needed to validate this association in the context of the risk of PND development.

Evaluation of association factors for labor episodic pain during epidural analgesia

Purpose

Epidural analgesia provides safe and effective labor pain relief. However, labor episodic pain can occur during epidural analgesia, requiring epidural top-ups, and may result in decreased patient satisfaction. The primary aim of our study was to investigate the factors associated with labor episodic pain during epidural analgesia.

Patients and methods

Electronic and hardcopy records of labor deliveries between January 2012 and December 2015 were reviewed at KK Women's and Children's Hospital, Singapore. The primary outcome was the prevalence of episodic pain. Demographic, clinical and anesthetic data were retrieved. Univariate and multivariate logistic regression analyses were used to identify associated risk factors for labor episodic pain experienced by parturients while receiving epidural analgesia. Model performance was assessed by area under the curve (AUC) from the receiver operating characteristic curve.

Results

The prevalence of labor episodic pain was 14.2% (2,951 of 20,798 parturients). The risk factors associated with labor episodic pain, which are given here as factor (OR, 95% CI), are the following: need for epidural resiting (11.4, 7.53-17.28), higher pain scores intrapartum (1.34, 1.32-1.36), higher Bromage scores (1.12, 1.02-1.22), the need for instrumental delivery (1.32, 1.16-1.52), the need for cesarean delivery (1.41, 1.26-1.59), the presence of venous puncture (1.29, 1.03-1.62), the presence of dural puncture (14.28, 5.92-34.43), the presence of high block (6.05, 1.39-26.35), the need for a urinary catheter (1.17, 1.17-1.34), larger volumes of local anesthetics used (1.01, 1.01-1.01) and higher body mass index (1.01, 1.01-1.02), and decreased maternal satisfaction (0.97, 0.97-0.98). The AUC was 0.80.

Conclusion

Knowledge of these factors may allow for future interventions in management to prevent labor episodic pain. Further research is needed to validate these association factors.

Development and validation of a predictive risk factor model for epidural re-siting in women undergoing labour epidural analgesia: a retrospective cohort study

Background

Epidural catheter re-siting in parturients receiving labour epidural analgesia is distressing to the parturient and places them at increased complications from a repeat procedure. The aim of this study was to develop and validate a clinical risk factor model to predict the incidence of epidural catheter re-siting in labour analgesia.

Methods

The data from parturients that received labour epidural analgesia in our centre during 2014–2015 was used to develop a predictive model for epidural catheter re-siting during labour analgesia. Multivariate logistic regression analysis was used to identify factors that were predictive of epidural catheter re-siting. The forward, backward and stepwise variable selection methods were applied to build a predictive model, which was internally validated. The final multivariate model was externally validated with the data collected from 10,170 parturients during 2012–2013 in our centre.

Results

Ninety-three (0.88%) parturients in 2014–2015 required re-siting of their epidural catheter. The training data set included 7439 paturients in 2014–2015. A higher incidence of breakthrough pain (OR = 4.42), increasing age (OR = 1.07), an increased pain score post-epidural catheter insertion (OR = 1.35) and problems such as inability to obtain cerebrospinal fluid in combined spinal epidural technique (OR = 2.06) and venous puncture (OR = 1.70) were found to be significantly predictive of epidural catheter re-siting, while spontaneous onset of labour (OR = 0.31) was found to be protective. The predictive model was validated internally on a further 3189 paturients from the data of 2014–2015 and externally on 10,170 paturients from the data of 2012–2013. Predictive accuracy of the model based on C-statistic were 0.89 (0.86, 0.93) and 0.92 (0.88, 0.97) for training and internal validation data respectively. Similarly, predictive accuracy in terms of C-statistic was 0.89 (0.86, 0.92) based on 2012–2013 data.

Conclusion

Our predictive model of epidural re-siting in parturients receiving labour epidural analgesia could provide timely identification of high-risk paturients required epidural re-siting.

A prospective observational study of ethnic and racial differences in neuraxial labor analgesia request and pain relief

BACKGROUND

As ethnic and racial diversity increases, it is important that anesthesia providers understand the expectations and concerns of this changing population regarding labor analgesia. Our objective was to evaluate ethnic/racial differences in labor analgesia characteristics with regard to the timing of request for neuraxial analgesia.

METHODS

Three hundred ninety-seven parturients were enrolled in this prospective observational cohort study. Term laboring parturients who planned vaginal delivery and requested neuraxial labor analgesia were eligible for inclusion. Data collected included cervical dilation at the time of neuraxial analgesia request, self-identified ethnicity/race, parity, education, insurance status, pain score before and after the initiation of neuraxial analgesia, and mode of delivery. The primary outcome was cervical dilation at the time of neuraxial analgesia request. Ethnicity/race classification was determined by asking the patient, "How would you define your ethnicity?" Patients were categorized into the ethnic/racial groups of non-Hispanic White, African American, Hispanic, or other. Univariate associations between cervical dilation and categorical variables were examined. Multivariate analysis was performed for the primary outcome of cervical dilation at the time of initiation of neuraxial analgesia.

RESULTS

At the time of neuraxial analgesia placement, the mean difference in cervical dilation of Hispanic parturients was 0.8 cm compared to non-Hispanic Whites (95% confidence interval [CI], 0.1-1.4; P = 0.047). After controlling for education, reason for placement, labor augmentation, and mode of delivery in a multivariate model, Hispanic parturients had 0.5 cm greater cervical dilation compared to non-Hispanic Whites, which was not significant (95% confidence interval, -0.1 to 1.1; P = 0.089).

CONCLUSIONS

Our data indicate that ethnicity/race plays a small role in acceptance and request for neuraxial labor analgesia.

Anesthetic considerations of parturients with obesity and obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterized by upper airway collapse and obstruction during sleep. It is estimated to affect nearly 5% of the general female population. Obesity is often associated with OSA. The physiological changes associated with pregnancy may increase the severity of OSA with a higher risk of maternal and fetal morbidity. However, very few parturients are diagnosed during pregnancy. These undiagnosed parturients pose great challenge to the attending anaesthesiologist during the perioperative period. Parturients at risk should be screened for OSA, and if diagnosed, treated. This review describes the anaesthetic concerns in obese parturients at risk for OSA presenting to the labor and delivery unit.

Advances in labor analgesia

The pain of childbirth is arguably the most severe pain most women will endure in their lifetimes. The pain of the early first stage of labor arises from dilation of the lower uterine segment and cervix. Pain from the late first stage and second stage of labor arises from descent of the fetus in the birth canal, resulting in distension and tearing of tissues in the vagina and perineum. An array of regional nerve blocks, systemic analgesic, and nonpharmacologic techniques are currently used for labor analgesia. Nonpharmacologic methods are commonly used, but the effectiveness of these techniques generally lacks rigorous scientific study. Continuous labor support has been shown to decrease the use of pharmacologic analgesia and shorten labor. Intradermal water injections decrease back labor pain. Neuraxial labor analgesia (most commonly epidural or combined spinal-epidural) is the most effective method of pain relief during childbirth, and the only method that provides complete analgesia without maternal or fetal sedation. Current techniques commonly combine a low dose of local anesthetic (bupivacaine or ropivacaine) with a lipid soluble opioid (fentanyl or sufentanil). Neuraxial analgesia does not increase the rate of cesarean delivery compared to systemic opioid analgesia; however, dense neuraxial analgesia may increase the risk of instrumental vaginal delivery.

A randomized trial of breakthrough pain during combined spinal-epidural versus epidural labor analgesia in parous women

BACKGROUND

There is controversy regarding the benefits and risks of combined spinal-epidural compared with epidural analgesia (CSE, EPID) for labor analgesia. We hypothesized that CSE would result in fewer patient requests for top-up doses compared to EPID.

METHODS

One-hundred ASA physical status I or II parous women at term in early labor (<5 cm cervical dilation) requesting analgesia were randomized in double-blind fashion to the EPID group (epidural bupivacaine 2.5 mg/mL, 3 mL, followed by bupivacaine 1.25 mg/mL, 10 mL with fentanyl 50 microg) or the CSE group (intrathecal bupivacaine 2.5 mg with fentanyl 25 microg). Both groups received identical infusions of bupivacaine 0.625 mg/mL with fentanyl 2 microg/mL at 12 mL/h. The primary outcome variable was the number of top-up doses requested to treat breakthrough pain.

RESULTS

There was no significant difference between the two groups in the percentage of patients requesting top-up doses (44% CSE vs 51% EPID; 95% confidence interval of the difference -28% to +14%) nor in the need for multiple top-up doses (14% CSE vs 15% EPID). Visual analog scale scores were lower in the CSE group compared to the EPID group at 10 min after initiation of analgesia [median 0 cm (0, 0) vs 4 cm (1, 6) respectively, P < 0.001] and at 30 min [0 cm (0, 0) vs 0 cm (0, 1), respectively, P = 0.03].

CONCLUSIONS

We did not find a difference in the need for top-up doses in parous patients; however, CSE provided better analgesia in the first 30 min compared to EPID.

The risk of cesarean delivery with neuraxial analgesia given early versus late in labor

BACKGROUND

Epidural analgesia initiated early in labor (when the cervix is less than 4.0 cm dilated) has been associated with an increased risk of cesarean delivery. It is unclear, however, whether this increase in risk is due to the analgesia or is attributable to other factors.

METHODS

We conducted a randomized trial of 750 nulliparous women at term who were in spontaneous labor or had spontaneous rupture of the membranes and who had a cervical dilatation of less than 4.0 cm. Women were randomly assigned to receive intrathecal fentanyl or systemic hydromorphone at the first request for analgesia. Epidural analgesia was initiated in the intrathecal group at the second request for analgesia and in the systemic group at a cervical dilatation of 4.0 cm or greater or at the third request for analgesia. The primary outcome was the rate of cesarean delivery.

RESULTS

The rate of cesarean delivery was not significantly different between the groups (17.8 percent after intrathecal analgesia vs. 20.7 percent after systemic analgesia; 95 percent confidence interval for the difference, -9.0 to 3.0 percentage points; P=0.31). The median time from the initiation of analgesia to complete dilatation was significantly shorter after intrathecal analgesia than after systemic analgesia (295 minutes vs. 385 minutes, P<0.001), as was the time to vaginal delivery (398 minutes vs. 479 minutes, P<0.001). Pain scores after the first intervention were significantly lower after intrathecal analgesia than after systemic analgesia (2 vs. 6 on a 0-to-10 scale, P<0.001). The incidence of one-minute Apgar scores below 7 was significantly higher after systemic analgesia (24.0 percent vs. 16.7 percent, P=0.01).

CONCLUSIONS

Neuraxial analgesia in early labor did not increase the rate of cesarean delivery, and it provided better analgesia and resulted in a shorter duration of labor than systemic analgesia.

Obstetric epidural analgesia

PURPOSE OF THE REVIEW

There has recently been a growing interest in developing and modulating the techniques of neuraxial analgesia to meet the changing individual needs of parturients for pain relief during the course of labour and delivery.

RECENT FINDINGS

Neuraxial analgesia is now very safe. Modern low-dose spinal-epidural regimens provide efficacious analgesia, stable maternal haemodynamics and few tolerable side effects. Complications are possible, however, due to the invasive nature of the technique, patient characteristics or medical malpractice.

SUMMARY

Labour epidural analgesia still remains the 'gold standard' of obstetric pain management, although spinal analgesia with the single-injection technique is an attractive option due to its simplicity, reliability and efficacy. Up till now, there has been no single new drug to overcome the superiority of neuraxial analgesia in obstetrics.