The Effect of a Lidocaine Test Dose on Analgesia and Mobility After an Epidural Combination of Neostigmine and Sufentanil in Early Labor

A Prospective Randomized Trial of Ropivacaine 5 mg with Sufentanil 2.5 μg as a Test Dose for Detecting Epidural and Intrathecal Injection in Obstetric Patients

Objectives: Traditional epidural test dose is somewhat unsuited in obstetrics because of potential risk of severe adverse effects when it is accidentally injected into the subarachnoid space. Some hospitals use a proportion of the total dose of epidural labor analgesia as a test dose. The aim of our study was to assess the effectiveness and safety of ropivacaine 5 mg with sufentanil 2.5 μg to detect intrathecal injection. Methods: This prospective randomized study enrolled parturients who had the demand for epidural labor analgesia and randomly divided them into two groups. Then, 5 mL of 0.1% ropivacaine with sufentanil 2.5 μg was injected into the epidural space or the subarachnoid space in the epidural (EP) group and the intrathecal (IT) group, respectively. The ability to detect intrathecal injection and side effects were assessed to work out the effectiveness and safety. Results: For spinal injection, the sensitivity and the specificity of the symptoms of either warmth or numbness or both assessed at 3 min were both 100%, and the observed negative predictive value (NPV) and positive predictive value (PPV) were 100%. All parturients in the IT group and 2.33% of parturients in the EP group had sensory blockade to cold or pinprick (p < 0.0001). A total of 77.55% (38 of 49) of parturients in the IT group were found to have a motor block. A 10 min assessment showed the median cephalad cold and pin levels were T8 and T10, respectively, and the median Bromage score was 4 in the IT group. Incidences of adverse effects in both groups were low. Conclusions: Ropivacaine 5 mg with sufentanil 2.5 μg is effective and safe to detect intrathecal injection as an epidural test dose in obstetric patients.

Epidural Neostigmine versus Fentanyl to Decrease Bupivacaine Use in Patient-controlled Epidural Analgesia during Labor: A Randomized, Double-blind, Controlled Study

BACKGROUND

The addition of opioids to epidural local anesthetic reduces local anesthetic consumption by 20% but at the expense of side effects and time spent for regulatory compliance paperwork. Epidural neostigmine also reduces local anesthetic use. The authors hypothesized that epidural bupivacaine with neostigmine would decrease total hourly bupivacaine use compared with epidural bupivacaine with fentanyl for patient-controlled epidural analgesia.

METHODS

A total of 215 American Society of Anesthesiologists physical status II, laboring parturients requesting labor epidural analgesia consented to the study and were randomized to receive 0.125% bupivacaine with the addition of either fentanyl (2 μg/ml) or neostigmine (2, 4, or 8 μg/ml). The primary outcome was total hourly local anesthetic consumption, defined as total patient-controlled epidural analgesia use and top-ups (expressed as milliliters of 0.125% bupivacaine) divided by the infusion duration. A priori analysis determined a group size of 35 was needed to have 80% power at α = 0.05 to detect a 20% difference in the primary outcome.

RESULTS

Of 215 subjects consented, 151 patients were evaluable. Demographics, maternal and fetal outcomes, and labor characteristics were similar among groups. Total hourly local anesthetic consumption did not differ among groups (P = 0.55). The total median hourly bupivacaine consumption in the fentanyl group was 16.0 ml/h compared with 15.3, 14.6, and 16.2 ml/h in the 2, 4, and 8 μg/ml neostigmine groups, respectively (P = 0.55).

CONCLUSIONS

The data do not support any difference in bupivacaine requirements for labor patient-controlled epidural analgesia whether patients receive epidural bupivacaine with 2 to 8 μg/ml neostigmine or epidural bupivacaine with 2 μg/ml fentanyl.

Comparison of Epidural Butorphanol with Neostigmine and Epidural Sufentanyl with Neostigmine for First Stage of Labor Analgesia: A Randomized Controlled Trial

Background:

Epidural administration of neostigmine appears to be safe in the obstetric population. Recently, few studies have concluded 10 μg sufentanil to be an effective adjuvant with epidural neostigmine in providing labor analgesia. However, no study has evaluated the analgesic effect of epidural butorphanol with neostigmine for the same.

Materials and Methods:

The parturients were randomly allocated to one of the three study groups - Group A (n = 30) received butorphanol 1 mg and neostigmine 7 μg/kg. Group B (n = 30) received sufentanil 10 μg and neostigmine 7 μg/kg. Group C (n = 30) received neostigmine 7 μg/kg and 0.9% normal saline. Maternal hemodynamic parameters and fetal heart rate (FHR) were continuously monitored. The level of sensory and motor block, and visual analog scale (VAS) pain score were recorded at designated time points. In addition, the total duration of analgesia, duration of labor, mode of delivery, and any maternal or fetal adverse effects were also recorded.

Statistical Analysis Used:

A one-way analysis of variance (ANOVA) with post hoc Tukey's test was used to compare mean value among the three groups for age, height, weight, gestational age, and cervical dilatation. Repeated measure ANOVA was used to compare mean difference among the time points and also the trend among the various time points for hemodynamic parameters, VAS pain score, and FHR. For inter-group comparison among the groups, post hoc Tukey test was used.

Results:

There was a statistically significant longer effect of analgesic drug in Group B with respect to Group A and C (P < 0.001); however, the parturient in Group C had minimum duration of analgesia. Epidural neostigmine combined with sufentanil produces effective analgesia in early labor (VAS <30 within 10 min in 63.3% of parturient and within 15 min in 83.3% parturient) with average duration of 111.67 ± 24.51 min without motor block or other side effect in mother and fetus. No significant effect was observed in the duration of labor and mode of delivery in-between the two groups, and none of the patients in any group had any maternal or fetal side effects.

Conclusion:

Epidural combination of sufentanil with neostigmine provided better pain relief in terms of the total duration of analgesia and the reduction in VAS pain scores at various time points in the initial 30 min of epidural administration of drugs during the first stage of labor in parturient when compared to the epidural combination of butorphanol with neostigmine.

A systematic review of the effects of adding neostigmine to local anesthetics for neuraxial administration in obstetric anesthesia and analgesia

BACKGROUND

Drugs used in obstetric patients must accomplish two goals: efficacy and safety for both mother and fetus. Neostigmine has been co-administered epidurally and intrathecally with local anesthetics and other adjuncts in the obstetric setting. The aim of this meta-analysis was to assess the efficacy and incidence of adverse events related to the use of neostigmine in obstetric anesthesia.

METHODS

A meta-analysis of randomized-controlled human trials was conducted using the data sources Google Scholar and PubMed (updated 1 November 2014). Inclusion criteria were: random allocation to treatment; comparison of neostigmine or neostigmine with local anesthetics and/or other adjuvants versus placebo or placebo with local anesthetics and/or other adjuvants; and approval by an ethics committee.

RESULTS

The use of neostigmine as an adjuvant in neuraxial anesthesia is associated with a reduction in the dose of local anesthetic during labor analgesia and postoperative analgesia following cesarean section: mean reduction of local anesthetic (ropivacaine or bupivacaine) vs. control -4.08 (95% CI -6.7 to -1.5) mg/h (P=0.002). The risk of nausea was increased vs. control with intrathecal neostigmine (OR 8.99 [95% CI 4.74 to 17.05], P <0.001) but not with epidural neostigmine (OR 0.97 [95% CI 0.46 to 2.05], P=0.94). Use of neuraxial neostigmine was associated with a decrease in the risk of pruritus but there was no increase in the incidence of hypotension, dizziness or sedation and no effect on the incidence of abnormal fetal heart rate patterns or Apgar scores.

CONCLUSIONS

Neuraxial administration of neostigmine significantly reduces local anesthetic consumption without serious adverse side effects to the mother or fetus. However, neostigmine is only recommended for epidural administration as intrathecal use significantly increases the incidence of maternal nausea and vomiting.

The evolution of spinal/epidural neostigmine in clinical application: Thoughts after two decades

Since the first clinical application of analgesia following spinal anticholinesterase by 1940's, several clinical double-blind studies have been conducted to date, where intrathecal doses of neostigmine in humans ranged from 750 to 1 μg, due to side-effects. Conversely, epidural neostigmine has been evaluated in proportionally higher doses and represents an alternative, but still deserves more investigation concerning both acute and chronic pain, as it seems devoid of important side-effects.

A prospective randomized trial of lidocaine 30 mg versus 45 mg for epidural test dose for intrathecal injection in the obstetric population

BACKGROUND

The epidural test dose, used to identify unintended intrathecal placement, should reliably produce a spinal block without posing a threat to the patient. Most anesthesiologists administer a dose of local anesthetic, commonly lidocaine 45 mg. Pregnant patients are more sensitive to local anesthetics; high and total spinal anesthesia have been reported in the pregnant population with this dose. We hypothesized that lidocaine 30 mg was as effective as lidocaine 45 mg in creating rapid objective evidence of a sensory or motor block.

METHODS

In this prospective, randomized, double-blind trial, patients scheduled for cesarean delivery were assigned to 1 of 4 groups: lidocaine 30 mg in the spinal or epidural space, or lidocaine 45 mg by the same routes. A blinded observer assessed the degree of sensory and motor block. The ability to identify intrathecal injection of each dose was compared. Sensory block above T6 dermatome and hypotension were recorded as side effects.

RESULTS

Intrathecal administration of lidocaine 30 mg produced rapid subjective and objective signs of neuroblockade within 3 minutes (100%, 95% confidence interval CI, 85%-100% for each). Lidocaine 45 mg produced similar results. All patients in both groups described their legs as warm or heavy after 3 minutes and had a motor block by 5 minutes. On the basis of an intrathecal catheter rate of 1:380, the observed negative predictive value for intrathecal placement if the patient described no sensory changes at 3 minutes was 100% (95% CI, 99.95%-100%) for 30 mg and 100% (95% CI, 99.93%-100%) for 45 mg. We did not identify a decrease in the rate of side effects with the lower dose.

CONCLUSIONS

Our results suggest that there is unlikely to be a large difference in the ability of these doses to detect unintentional intrathecal catheter placement. While the negative predictive value for intrathecal injection is very high for both doses, the 95% CI for the sensitivity of either dose is too wide to demonstrate clinical safety to identify all intrathecal catheters. A much larger study is warranted to assess whether there is a lower sensitivity with the 30-mg dose, or a propensity toward high cephalad motor block levels with the 45-mg dose.

Comparison of three doses of epidural fentanyl followed by bupivacaine and fentanyl for labor analgesia

BACKGROUND

Epidural fentanyl 100 microg after lidocaine-epinephrine test dose has been shown to provide adequate analgesia in early labor. This investigation determines the effect of three different bolus doses of epidural fentanyl on duration and quality of analgesia during early first stage of labor.

METHODS

In this prospective, double-blind study, 103 laboring nulliparous at cervical dilation <5 cm were enrolled. After an epidural test dose of lidocaine (60 mg) with epinephrine (15 microg), parturients received, randomly, bolus of epidural fentanyl 50, 75, or 100 microg, followed by a continuous infusion of epidural bupivacaine 0.0625% and fentanyl 3 microg/ml at a rate of 10 ml/h. Pain scores and maternal sedation, pruritus, nausea, and vomiting were recorded 10, 20, and 30 min after fentanyl, and every 30 min thereafter until first request for additional analgesia.

RESULTS

Adequate analgesia was achieved in 87% (28/32), 94% (35/38), and 94% (31/33) in the fentanyl 50, 75, and 100 microg groups within 20 min. Mean duration of analgesia before re-dosing was significantly longer in fentanyl 100 and 75 microg groups (185.6+/-82.9 and 188.5+/-82.2 min, respectively) as compared with fentanyl 50 microg group (133.6+/-46.2 min, P<0.016). There was no difference in the incidence of maternal side effects or neonatal Apgar scores among the three groups.

CONCLUSION

After a test dose of lidocaine-epinephrine, the three epidural fentanyl doses produced similar effective labor analgesia. However, epidural fentanyl 75 microg followed by epidural infusion of dilute bupivacaine and fentanyl produced longer duration of analgesia than fentanyl 50 microg followed by the same infusion, with no further prolongation when the dose of fentanyl was increased up to 100 microg.