What determines the analgesic effect of paracervical block?

BACKGROUND: The objective of the study was to evaluate the analgesic effect of paracervical block (PCB) in labor pain relief and to discover the determinants associated with good analgesia. METHODS: In a prospective trial, 341 women received PCB for pain relief in the first stage of labor, with 10 ml of 0.25% levobupivacaine or racemic bupivacaine. All these pregnancies were uncomplicated and the progress of labor was normal. The analgesic effect of PCB was measured by using a visual analog scale (VAS). The factors associated with good pain relief (>50% decrease in the VAS score within 30 min) were analyzed statistically by Student's t-test or the Mann-Whitney test (continuous variables), Fisher's exact test (categorial variables) and after univariate analysis by logistic regression analysis. For pairwise comparisons, Wilcoxon's signed ranks test was used. RESULTS: Good pain relief was achieved in 47.2% of the cases. 12.3% of the parturients needed subsequent epidural or spinal analgesia. In logistic regression analysis, primiparity, a high pain score before PCB, and PCB given by a specialized obstetrician were found to affect the level of pain relief 30 min after PCB. CONCLUSIONS: The best pain relief after PCB was achieved among primiparas. Good pain relief was connected with a high pain score before PCB and an experienced obstetrician.     

Bupivacaine paracervical block. Effects on the fetus and neonate.

To evaluate effects on the fetus and neonate, 53 paracervical blocks were administered to 38 low-risk parturients using a controlled superficial injection of 0.25% bupivacaine. Continuous fetal heart rate monitoring revealed no instance of bradycardia or late deceleration pattern. Apgar scores, cord arterial and venous pH values, and neurobehavioral evaluations of the neonates were similar to those observed in other low-risk patients. The effectiveness of pain relief of the blocks was less than expected or reported by other authors. Although we observed no harmful effects on the fetus or neonate from the superficial paracervical injection of bupivacaine, we did not find this combination of drug and technique to give dependable, effective pain relief in labor.     

A comparative study of the safety of 0.25% levobupivacaine and 0.25% racemic bupivacaine for paracervical block in the first stage of labor

BACKGROUND: The objective of the study was to evaluate and compare the safety of levobupivacaine and racemic bupivacaine for paracervical block (PCB) in the first stage of labor after uncomplicated pregnancy. METHODS: Forty women in an open pilot study and 397 women in a double-blind randomized study received PCB for pain relief in the first stage of labor, either with 25 mg of levobupivacaine or with 25 mg of racemic bupivacaine. The incidence of cardiotocographic pathology was compared between the groups using Fisher's exact test. The 95% confidence intervals for the between-group difference were calculated by Newcombe's method. RESULTS: In the randomized double-blind study, the incidence of any pathological result in cardiotocography (CTG) was 10.4% in the levobupivacaine group and 12.8% in the racemic bupivacaine group. The incidence of fetal bradycardia in the groups was 2.6 and 3.8%, respectively. All the cardiotocographic changes were transient, and no operative intervention was indicated because of CTG. No difference in the analgesic effect between the drugs was found. Most of the parturients in the levobupivacaine group (97%) and in the racemic bupivacaine group (96%) had spontaneous vaginal delivery. Neonatal outcome was good in both groups. CONCLUSIONS: No difference in cardiotocographic pathology was found between PCB with levobupivacaine compared with PCB with racemic bupivacaine. The incidence of bradycardia was low. PCB was found to be a safe pain-relief method for low-risk parturients.     

Does pain relief during delivery decrease the risk of postnatal depression?

BACKGROUND: To test the hypothesis that sufficient pain relief during delivery decreases the risk of postnatal depression. METHODS: As part of a prospective follow-up study of the risk factors for postnatal depression and its impact on the mother-infant interaction and child development, 185 parturients filled in the Edinburgh Postnatal Depression Scale (EPDS), first during the first postpartum week and again (n = 162) 4 months later. The incidence and the risk of high EPDS scores was calculated according to the mode of delivery and the mode of pain relief during vaginal delivery, also after adjusting for the length of labor. RESULTS: Mothers who received epidural/paracervical blockade during their delivery spent less time in the delivery room than mothers in the nitrous oxide/acupuncture group (p = 0.033) or mothers with no pain relief (p = 0.026) and had shorter length of labor than mothers without pain relief (p = 0.04). The adjusted risk of depressive scores at the first postnatal week was decreased in the epidural/paracervical group when compared with no analgesia group (OR: 0.25, 95% CI: 0.09-0.72). This difference was not shown at 4 months postpartum. Elective or emergency cesarean section did not increase the risk of high EPDS scores at the first week or at 4 months postpartum. CONCLUSION: The mode of pain relief during vaginal delivery seems to be associated with the incidence of postpartum depression, especially immediately after delivery.     

Prolonging paracervical block anesthesia: addition of dextran to 2-chloroprocaine.

Forty parturient women received paracervical block (PCB) anesthetics during labor with 2-chloroprocaine (2-CP) and epinephrine in either normal saline or dextran. Thirty-six patients were though to have adequate anesthesia. Nineteen patients who recived 2-CP in saline had a mean duration of anesthesia lasting 55.4 min; one fetus developed post-PCB bradycardia. Seventeen patients who received 2-CP in dextran had a mean duration of anesthesia lasting 72.7 min; no fetal bradycardia was observed following PCB. Neonatal depression, expressed by 1 and 5 min Apgar scores below seven, was not observed in either group. The addition of dextran to 2-CP significantly prolongs the duration of PCB anesthesia and does not appear to compromise the fetus. The pain relief provided by a single PCB with 2-CP in dextran is still relatively short and would not persist throughout the active phase of labor in most parturient women.     

The bupivacaine paracervical block in labor and its effect on quantitative uterine activity.

This study utilized internal fetal monitoring and an on-line voltage control oscillator for measurement of uterine activity unit (UAU) determination in patients who received a paracervical block (PCB) with the use of bupivacaine hydrochloride (Marcaine). The total dose of 25 mg (5 cc/side) of 0.25% bupivacaine used for PCB in 32 patients produced no ill effects to the fetus, as reflected by baseline fetal heart rate (FHR), beat-to-beat variablity, or Apgar scores. No adverse maternal effects were noted, and anesthesia was rated good or excellent in 81% of patients. Rate of cervical dilation remained the same or increased in 29 of 32 patients. Quantitative UAUs showed a significant decrease in the third 10-minute interval after block in primiparas, but no significant change in multiparas or in the group taken as a whole. Total UAUs before versus after PCB for either group or taken together were not statistically different. A decreasing trend in UAUs after PCB versus a positive regression line from activity prior to the block was noted.     

Submucous paracervical blockade compared with intramuscular meperidine as analgesia during labor: a double-blind study

A double-blind study was carried out to compare the effect of submucous paracervical blockade using 12 mL 0.25% bupivacaine (55 women) to the effect of intramuscular injection of 75 mg meperidine (62 women) during the first stage of labor. All 117 were normal primiparous pregnancies. Seventy-eight percent of the women in the paracervical blockade group achieved full or acceptable pain relief against 31% in the meperidine group (P less than .01). Transient fetal bradycardia occurred in two cases in the paracervical blockade group and one in the meperidine group; all infants were born in good condition. Fetal distress, defined as an umbilical artery pH of 7.15 or less and/or a one-minute Apgar score of 7 or less was more frequent in the meperidine group (16 infants) than in the paracervical blockade group (six infants) (P less than .05). Submucous paracervical blockade is superior to intramuscular meperidine as pain relief during labor. Furthermore, meperidine results in more infants with asphyxia as compared with paracervical blockade.     

Utility of preemptive local analgesia in vaginal hysterectomy

OBJECTIVE: Our purpose was to determine whether preemptive administration of long-acting local anesthetics before vaginal hysterectomy will improve postoperative pain. STUDY DESIGN: A blinded, randomized, trial of paracervical injection of 0.5% bupivacaine with epinephrine or normal saline solution placebo with epinephrine was conducted. Verbal analog pain scores were collected at 1, 2, 3, 4, 6, and 24 hours after surgery. Morphine use in the postanesthesia care unit and by patient-controlled morphine analgesia was recorded. RESULTS: Twenty patients were enrolled. Nine were randomized to bupivacaine. There was no difference between groups regarding age, length of surgery, blood loss, or length of stay. Pain scores were lower in the bupivacaine group by analysis of variance (P=.03). Total morphine and patient-controlled analgesia morphine was significantly less in patients receiving bupivacaine (P=.01 and.04). CONCLUSION: Paracervical block with a 0.5% bupivacaine with 1:200,000 epinephrine before vaginal hysterectomy is associated with lower pain scores and a reduction in morphine requirements after surgery.     

Fetal oxygen saturation during epidural and paracervical analgesia

BACKGROUND: We wanted to assess changes in fetal oxygenation during maternal epidural or paracervical analgesia in labor. METHODS: A prospective, open and non-randomized study. Twenty healthy parturients were enrolled before they asked for pain relief. Informed consent was obtained. Fetal and maternal oxygen saturations were measured before and up to 1 h after the initiation of analgesia. Fetal oximetry was performed with the Nellcor N-400 oximeter+FS-14B fetal oxygen sensor (Nellcor Puritan Bennett, Pleasanton, California, USA). Maternal oximetry was done with Datex Satlite portable monitor (Datex, Finland). Visual analog scale was used for assessing pain relief. Two-way analysis of variance and students t-test were used for statistical analyses. RESULTS: Fetal oxygenation initially improved in both groups. The saturation then returned to baseline in both groups. In the epidural group, the values remained at baseline or slightly below, while in the paracervical group the saturation remained a little higher than baseline (p=0.009). No change was seen in maternal oxygenation or heart rate. No change in fetal heart rate was found either. Epidural block was superior to paracervical block with respect to pain relief (p=0.002). CONCLUSIONS: There was a small but significant difference in fetal oxygenation between epidural and paracervical groups during the observation period. The magnitude of the difference is hardly clinically significant. A larger, randomized study is needed to elucidate the mechanisms behind this finding.     

Paracervical block and elective abortion: the effect on pain of waiting between injection and procedure

OBJECTIVE: Our purpose was to assess the effect on pain and patient satisfaction of waiting between paracervical block and dilation during first-trimester abortions. STUDY DESIGN: One hundred ninety-nine women seeking pregnancy termination were randomly assigned to a no-wait group (group 1) and a 3- to 5-minute wait between injection and dilation group (group 2). Subjects rated their pain on a visual analog scale at four times: prior to procedure, with dilation, with aspiration, and 30 to 45 minutes after procedure. RESULTS: No significant differences were observed in pain or satisfaction ratings reported by group 1 (n = 93) and group 2 (n = 101). A significant decrease in pain with dilation (1.21 cm decrease, P =.009) and aspiration (1.15 cm decrease, P =.0015) was observed among patients who received fentanyl. CONCLUSION: Delay between paracervical injection and dilation during first-trimester abortion does not have an impact on patient pain or satisfaction. Fentanyl decreased pain scores by 20% to 25% during the procedure.     

Maternal and fetal effects of low-dosage bupivacaine paracervical block

Vasoconstriction of the uterine arteries, hypertonus of the uterus, and the direct toxic effects of a local anesthetic on the fetus or a combination of the above have been presented as etiological factors of fetal bradycardia following paracervical block. The reduce fetal side-effects a superficial and lowdosage technique of PCB have been advocated. We have studied the effects of 25 mg of bupivacaine PCB using the above technique on fetal heart rate pattern (FHR), fetal acid-base balance, uterine activity, placental blood flow and maternal and fetal plasma levels of bupivacaine in 38 patients. The analgesic effect of a single 25 mg of bupivacaine PCB was good in 76%, moderate in 12% and poor in 12% of the cases. No changes in maternal heart rate or in blood pressure were noted. Fetal bradycardia defined as a decrease of mean fetal heart rate of at least 20 bpm or an absolute rate less than 100 bpm and a duration greater than two minutes occurred in 12% of the cases. The mean amplitude of the baseline fetal heart rate variability decreased significantly after PCB and a silent pattern (an amplitude less than 5 bpm) was observed in 20% of the cases. The most frequent (27%) pathological finding in our study was the disappearance of FHR accelerations after PCB. Similarly early and late decelerations of FHR occurred more often after PCB than during the control period before the block. The fetal pH from scalp blood samples did not, on average, decrease after PCB, but did so in cases with fetal bradycardia. Intervillous blood flow as measured by the 133Xe washout method did not change when measured before and after PCB. In addition in three cases with fetal bradycardia the changes in the intervillous blood flow were minimal. No significant changes in the mean uterine tone, amplitude and frequency of contractions were observed after PCB. However, an obvious uterine hypertonus was observed after PCB was observed in three cases of fetal bradycardia but not in two other cases of bradycardia or in the 8 cases of silent FHR pattern. Mean maternal bupivacaine concentration 20 minutes after PCB was 0.14 +/- 0.06 microgram/ml and 0.07 +/- 0.04 microgram/ml at birth. Simultaneous fetal and umbilical venous and arterial concentrations were correspondingly 0.04 +/- 0.02 microgram/ml, 0.03 +/- 0.01 microgram/ml and 0.03 +/- 0.01 microgram/ml, and they were significantly lower than respective maternal concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)     

A survey of parturients using epidural analgesia during labour. Considerations relevant to antenatal educators

The use of epidural analgesia (EA) during labour is increasing in Australasia. This highlights the need for improved educational and resource materials, current factual information about EA, and identification of consumer attitudes towards EA. In this survey, 350 parturients who had recently used EA for labour pain relief in a single maternity unit were asked to complete a questionnaire about their expectations and experience. The response rate was 90%. Prepartum information was most commonly derived from hearsay and least commonly from medical health professionals, 56% of respondents wanted pain to be made tolerable and 34% wanted complete pain relief. Almost half considered unrestricted mobility and delivery without obstetric assistance important. A minority were concerned about possible effects of EA on the baby or labour outcome. Anticipated pain during epidural placement was significantly greater than that experienced. Satisfaction with EA was high, although 36% described unpleasant or annoying effects associated with EA. Parent educators and epidural service providers should be aided by knowledge of where parturients obtain information and of consumer views about EA.     

Augmentation of bupivacaine analgesia in labor by epidural morphine

The analgesic properties and motor effect of epidural 0.25% bupivacaine (8 mL) were compared with those of epidural morphine (2 mg in 10 mL saline) followed by 8 mL of 0.25% bupivacaine. The study was performed on two groups of parturients (30 in each group) in active labor. Pain relief in the morphine-bupivacaine group lasted for a mean of 131.1 minutes (SD +/- 49.8) as opposed to the plain bupivacaine group -57 minutes (SD +/- 15.28). Satisfaction from analgesia in the morphine-bupivacaine group was higher as well. Motor involvement was not seen in either group. Perineal pain relief in the postpartum period lasted for a mean of 16 hours and 40 minutes in the morphine-bupivacaine group. It was concluded that the concomitant use of epidural morphine augmented the analgesic effect of 0.25% bupivacaine without motor effect.     

Effects of epidural fentanyl on labor pain during the early period of the first stage of induced labor in nulliparous women.

BACKGROUND AND PURPOSE: It is generally accepted that epidural injection with local anesthetics and narcotics administered when the cervix has dilated to a diameter exceeding 4 cm can adequately control labor pain. However, many nulliparous women still suffer from labor pain for a few hours prior to the administration of epidural analgesia. This study examined the effectiveness of relief of labor pain obtained by injection of narcotics epidurally once the labor pain begins and the subject requests analgesia. METHODS: Subjects scheduled for induced labour were divided into three groups: Group A (n = 60) received 5 x 10(-4)% fentanyl (10-20 mL) administered epidurally to relieve early first-stage labor pain. Group B (n = 60) received no analgesic in the early first stage of labor. For groups A and B, when cervical dilatation exceeded 4 cm, 10 to 15 mL of 5 x 10(-2)% bupivacaine and 2 x 10(-4)% fentanyl were injected epidurally and a continuous low dosage was maintained until full dilatation of the cervix resulted. Group C (n = 198) received no analgesic during the entire labor course. RESULTS: There were no significant differences in the duration of the early period of the first stage of labor, the duration of the late period of the first stage, the duration of the second stage, the Apgar score, or the arterial blood gas of neonates among the three groups. However, group C had a significantly higher cesarean section rate (28.8%) than group A (16.7%) or group B (15%). Pain scores assessed with the Visual Analog Scale (VAS) throughout the entire labor course, were lower in group A than in group B; particularly during the early period of the first stage. The VAS scores in both groups A and B were significantly lower than those in group C during the late period of the first stage of labor. CONCLUSIONS: The results indicate that once labor pain begins and the subject requests analgesia, epidural injection with fentanyl alone can relieve labor pain during the early period of the first stage. The analgesia does not cause adverse effects to the mothers or neonates. In addition, the labor course and the method of delivery are not affected.     

A comparison between the effectiveness of epidural analgesia and parenteral pethidine during labor

The study was aimed to define parturients' opinion on either epidural analgesia or intravenous pethidine, and to determine the effect of both analgesics after delivery. We interviewed and examined 401 consecutive parturients who requested analgesia during the beginning of their active stage of labor. Of those, 131 women requested and underwent epidural analgesia, and 270 received parenteral pethidine. The pain experienced before admission of any analgesia, was significantly higher in the epidural group than in the parental group (mean visual analog scale (VAS) score 8.9 and 8.4, respectively; P=0.004). However, after analgesics, women from the epidural analgesia experienced significantly less pain during labor as compared to those receiving pethidine (mean VAS scores 5.05 vs. 9.14, respectively; p<0.001). The pain scores 24 h after labor were significantly lower in patients who underwent epidural analgesia (1.69 vs. 2.13, respectively; p<0.001). We conclude that epidural analgesia is more effective than parenteral analgesia in pain and discomfort relief. This method is helpful also the day after delivery. Thus, epidural analgesia should be strongly recommended to all patients who do not have any medical contraindications to this method of treatment.     

A randomized trial of postoperative wound irrigation with local anesthetic for pain after cesarean delivery

OBJECTIVE: The purpose of this study was to investigate the efficacy of continuous local anesthetic infusion system for pain control after cesarean delivery. STUDY DESIGN: This was a randomized prospective double-blind study. Patients who underwent cesarean delivery had a pain system implanted subcutaneously after closure of the fascia. Patients were randomized to receive an infusion of either 0.25% bupivacaine (n = 20) or normal saline solution (n = 16) into the wound for 48 hours. Postoperative pain (determined with a visual analog scale) and postoperative morphine use were assessed at 12, 24, and 48 hours. RESULTS: There were no significant differences in patient demographics or visual analog pain scores at any time interval between the bupivacaine versus the placebo group. However, narcotic requirements to produce this amount of pain relief were significantly less in patients who received bupivacaine infusion rather than normal saline solution at all time intervals. CONCLUSION: The continuous local anesthetic infusion system appears to be effective in reducing postoperative morphine use after cesarean delivery.     

Intramuscular pethidine (meperidine) during labor associated with metabolic acidosis in the newborn

Analyses of fetal heart rate (FHR) variability, visual evaluation of FHR decelerations, and respiratory gas analyses of the umbilical vein were performed in 27 labors, where one dose (50 or 75 mg) of intramuscular pethidine was used for pain relief, in 47 labors with one paracervical blockade (6 ml 0.5% marcaine) and in a control group of 135 labors without any pain relief. Umbilical vein pH, standard bicarbonate and base excess were lowest in the pethidine group and highest in the PCB group. The duration of labor was shortest in the control group, but there was no difference in the duration of labor of the two anesthesized groups. Intramuscular pethidine seems to associate with umbilical metabolic acidosis and PCB should be preferred to it, when an obstetrician is available.     

Effects of local anesthetics on fetal heart rate patterns and neonatal neurobehavior

Changes in FHR after local anesthetic administration were analyzed and the neonatal neurobehavioral status was evaluated by the use of Amiel-Tison's NACS (Neurologic and Adaptive Capacity Scoring System). The following results were obtained. After the epidural administration of 35 mg bupivacaine transient ominous FHR changes were noted in 12 out of 99 cases, two of which followed maternal hypotension and five followed uterine hyperactivity. Among 13 out of 43 paracervical blocks by 200mg lidocaine transient FHR changes were noted; "post PCB bradycardia"/late deceleration with decreasing variability was seen after 7 blocks and variable deceleration with increasing variability after 6 blocks. The plasma bupivacaine level of the umbilical vein was 154.4 +/- 24.5 ng/ml (UV/MV 0.26) and of the neonatal vein at the 4th day was 15.1 +/- 3.8 ng/ml (in 71% of cases there was a trace). The score of NACS tended to be lower 3-6 hrs. after birth, but at the 4th neonatal day no significant difference was noted between groups with and without regional analgesics. Although local anesthetics might cause some FHR changes in cases with low fetal reserve, clinical effects are minimal in cases of term AGA. However, particular care must be taken in such high risk cases as IUGR.     

The effect of ultra low dose epidural analgesia on newborn breastfeeding behaviors

OBJECTIVE: To determine whether a difference in breastfeeding behaviors could be observed between newborns whose mothers received epidural analgesia for labor pain relief and those newborns whose mothers received no pain medication in labor. DESIGN: There were two groups of neonates in this study. One group was born to mothers who received epidural analgesia, and one group was born to mothers who received no pain medication for labor. Both groups were observed for initial breastfeeding behaviors using the Premature Infant Breastfeeding Behavior Scale following birth and at 24 hours. Central nervous system functioning in the newborn was measured with the Neurologic and Adaptive Capacity Score at 2 and 24 hours of age. SETTING: A large tertiary hospital in northeast Ohio. PARTICIPANTS: Fifty-six breastfeeding mother-newborn dyads. All mothers were healthy multiparae who gave birth vaginally to normal, full-term, healthy newborns. MAIN OUTCOME MEASURES: Newborns were observed for rooting, latch on, sucking, swallowing, activity state, and neurobehavior. RESULTS: There were no statistically significant differences in breastfeeding behaviors at birth or at 24 hours of age. CONCLUSION: A possible cause for the lack of significant results may have been the ultra low dose of bupivacaine and fentanyl used in this sample.     

Comparison of neonatal effects of epidural and general anesthesia for cesarean section

We assessed the influence of anesthetic technique for cesarean section on neonatal outcome. Thirty parturient women (ASA I/II) were randomly allocated into two groups. In Group GA general anesthesia was induced with 4 mg.kg(-1) thiopental and 1.5 mg.kg(-1) succinylcholine. In group EA epidural anesthesia was performed with 20 ml 0.375% bupivacaine through L(3-4) inter-space. 1-min Apgar scores were significantly higher in group EA (p < 0.001). Neurologic and Adaptive Capacity scores at 2 and 24 h were higher in group EA (p < 0.001). In terms of blood gas values, umbilical arterial pH and pO(2) values were higher in group EA (p < 0.05 and p < 0.001, respectively). The first breast-feeding intervals were found to be shorter in group EA (p < 0.001). We conclude that in terms of better Apgar and NAC scores, acid-base status and earlier initiation of breast-feeding, the epidural anesthesia may be preferred to general anesthesia in cesarean section.