A double-blind randomised comparison of intravenous patient-controlled remifentanil with intramuscular pethidine for labour analgesia

In a prospective, double-blind, randomised controlled trial, we compared the efficacy of patient-controlled analgesia using remifentanil (25-30 μg per bolus) with intramuscular pethidine (50-75 mg) for labour analgesia in 69 parturients. Parturients receiving patient-controlled analgesia reported less pain than those receiving intramuscular pethidine throughout the study period (p < 0.001), with maximal reduction in visual analogue pain score at 2 h after commencement of analgesia (mean (SD) 20 (17) in the patient-controlled analgesia group and 36 (22) in the intramuscular pethidine group. The median (95% CI) time to the first request for rescue analgesics was significantly longer with patient-controlled analgesia (8.0 (6.8-9.2) h) compared with intramuscular pethidine (4.9 (3.8-5.4) h, p < 0.001). Maternal satisfaction scores were also higher with remifentanil compared with intramuscular pethidine (p= 0.001). There was no report of sedation, aponea or oxygen desaturation in either group, and Apgar scores were similar between groups. We conclude that patient-controlled analgesia with remifentanil provides better labour analgesia and maternal satisfaction than intramuscular pethidine. At this dose, maternal and fetal side effects were uncommon.     

Maternal opinion about analgesia for labour. A controlled trial between epidural block and intramuscular pethidine combined with inhalation

In a randomised controlled trial epidural analgesia with bupivacaine 0.5% (mean dose 112.8 mg) was compared with pethidine (mean dose 200 mg) and inhalational analgesia in primipara (28 and 30 mothers) and multipara (17 and 18 mothers). Mothers who had an uneventful pregnancy and labour and agreed to have either treatment were studied during labour and followed-up at interviews for 5 months after delivery. Epidural block was rated significantly superior in respect of pain relief and comfort, there were no differences between the groups in reports of perineal discomfort. Twice as many primipara required forceps delivery after epidural block. Very few mothers, in each group, reported something missing in their experience of childbirth. Two thirds of each group would use the same method again. Epidural block can therefore be recommended to uncommitted mothers as a satisfying and effective method of pain relief for labour.     

The addition of pethidine to epidural bupivacaine in labour--effect of changing bupivacaine strength.

The effects of varying the strength of bupivacaine used in epidurals for the relief of labour pain was examined. The trial randomly allocated sixty women in the first stage of labour to one of three groups. All women were of ASA status 1 or 2 and had uncomplicated pregnancies. Subjects in each group received pethidine 25 mg in 10 ml of either 0.125%, 0.1875%, or 0.25% bupivacaine. Pain scores for each patient were then assessed over the following thirty minutes. Duration of analgesia and subsequent dose requirements were examined. No difference in pain scores between groups at thirty minutes after injection of the test solutions was found. The 0.25% solution group did however have a more rapid onset of analgesia with the majority of patients in this group achieving their maximum effect between ten and twenty minutes after injection. Duration of analgesia was not prolonged by using the stronger solutions. This study suggests that when epidural pethidine 25 mg is added to local anaesthetic solutions of bupivacaine, adequate analgesia for the first stage of labour is achieved with the 0.125% bupivacaine solution. The use of stronger solutions of bupivacaine achieves no greater degree of analgesia nor longer duration of action, although the onset of analgesia may be faster with the stronger solutions. Further investigations are needed to determine if 25 mg of pethidine is the best choice of dose to use under these circumstances.     

Labour analgesia and obstetric outcomes

Neuraxial analgesic techniques are the gold standards for pain relief during labour and delivery. Despite the increased use and known benefits of neuraxial labour analgesia, there has been significant controversy regarding the impact of neuraxial analgesia on labour outcomes. Review of the evidence suggests that effective neuraxial labour analgesia does not increase the rate of Caesarean delivery, even when administered early in the course of labour; however, its use is associated with a prolonged second stage of labour. Effective second-stage analgesia might also be associated with an increased rate of instrumental vaginal delivery.     

The median local analgesic dose of intrathecal bupivacaine with hydromorphone for labour: a double-blind randomized controlled trial

Purpose

Neuraxial hydromorphone has been reported to provide rapid onset of labour analgesia, effective segmental pain relief, and a longer duration of action than commonly used lipophilic opioids. This study was conducted to test the hypothesis that intrathecal hydromorphone reduces the dose requirement for intrathecal bupivacaine to induce rapid analgesia for women in the first stage of labour.

Methods

In this double-blind randomized controlled sequential allocation trial, 88 labouring parturients received combined spinal-epidural analgesia at 2-6 cm cervical dilation. Participants received intrathecal bupivacaine alone or bupivacaine plus hydromorphone 100 μg with the bupivacaine dose determined using up-down sequential allocation. An effective dose was defined as a visual analogue pain score of ≤10 mm (on a 100-mm pain scale) reported within 20 min of injection. The median effective doses were calculated using the formula of Dixon and Massey and verified using isotonic regression.

Results

A decrease was observed in the median local analgesic doses (effective dose [ED50]) estimated according to the formulas of Dixon and Massey, with a between-group difference of ?0.45 mg. The precision of the estimate was wide-ranging (95% confidence interval ?1.23 to 0.33), so no definitive conclusion can be drawn.

Conclusion

Further research is needed to determine whether or not intrathecal hydromorphone 100 μg changes the dose of intrathecal bupivacaine required to induce labour analgesia within 20 min.

Trial registration

The trial was conducted in 2007 prior to widespread acceptance of the standard for clinical trial registration.     

The effect of adding fentanyl to ropivacaine 0.125% on patient-controlled epidural analgesia during labour

The use of patient-controlled epidural analgesia (PCEA) for labour analgesia is rapidly gaining acceptance. However, the ideal PCEA solution and PCEA program remains uncertain. We studied the effect of adding fentanyl 2 micrograms/ml on demand-only PCEA using ropivacaine 0.125% for labour analgesia. With the approval of the Hospital Ethics Committee, this prospective randomized controlled trial was conducted on 36 nulliparous ASA 1/2 parturients in early, but established, labour. Upon written consent, epidural analgesia was started with 10 ml ropivacaine 0.2%. The parturients subsequently were randomized to receive either ropivacaine 0.125% (n = 18) or ropivacaine 0.125% with fentanyl 2 micrograms/ml (n = 18). The PCEA was programmed to a demand-only mode with bolus of 5 ml, lockout time of 10 minutes and maximum volume per hour of 20 ml. The degree of pain relief was similar in both groups. However, the total amount of ropivacaine used per hour was lower in the group that received fentanyl (median 7.1 vs 10.1 mg, P < 0.05). This was not associated with a decrease in motor blockade or a decrease in instrumental deliveries. The ratio of successful PCEA demand to total number of demands, the satisfaction score and the maternal-fetal outcome were similar in both groups. In conclusion, the addition of fentanyl had a dose-sparing effect on the requirement of ropivacaine. This PCEA regimen produced a low incidence of motor block, good labour pain relief and excellent patient satisfaction.     

Ropivacaine versus bupivacaine 0.125% with fentanyl 1 microg/ml for epidural labour analgesia: is daily practice more important than pharmaceutical choice?

Ropivacaine might be superior to bupivcaine for epidural labour analgesia because it appears to induce less lower extremity motor blockade. The clinical relevance of this difference is not yet clear. METHODS: In a double-blind randomised trial bupivacaine and ropivacaine each at 0.125% with 1 microg/ml fentanyl were compared for epidural labour analgesia. This study was performed in two university hospitals. RESULTS: Sixty-three nulliparous women with singleton pregnancies at term were included. There were no differences between bupivacaine and ropivacaine as far as motor blockade, analgesic outcome, mode of delivery and neonatal outcome are concerned. However, the clinical management of epidural analgesia differed significantly between the two institutions involved. Parturients of one institution had their epidural catheter placed earlier, needed less top-up medication, and had more successful mobilisations, when compared to the other institution. CONCLUSIONS: Institutional clinical practice can be significantly different. Pharmacological differences between bupivacaine and ropivacaine at 0.125% with 1 microg/ml fentanyl seem to be less important than differences between institutions in terms of clinical practice.     

Low dose intrathecal ropivacaine with or without sufentanil provides effective analgesia and does not impair motor strength during labour: a pilot study

PURPOSE: Although ropivacaine has been used to provide spinal anesthesia in the surgical population, its intrathecal administration for labour analgesia has only recently been described. We evaluated the effects of low dose intrathecal ropivacaine with or without sufentanil for labour analgesia. METHODS: Thirty-six term parturients in active labour were randomly assigned to receive 3 mg of intrathecal ropivacaine (group R) or 3 mg ropivacaine with 10 microg of sufentanil (group RS). Patients were evaluated by a blinded observer for hypotension, linear analogue score (VAS 0-100) for labour pain, motor power in the lower limbs, onset of analgesia, sensation to cold and pin prick, duration of analgesia, and neonatal Apgar scores. The following day patients were assessed for satisfaction, headache and neurologic deficit. RESULTS: The mean duration of analgesia in the R group was 41.4 +/- 4.9 min and 95.0 +/- 6.1 min in the RS group (mean +/- SEM, P=0.0001). All subjects had satisfactory analgesia at five minutes, although analgesia from the ropivacaine- sufentanil combination was superior to that provided by ropivacaine alone. Total duration of labour was no different between the groups (R- 306 +/- 34, RS- 384 +/- 44 min, P=0.17). No patient showed evidence of motor block. All patients were satisfied with the labour analgesia. No neurological complications were observed. CONCLUSIONS: Low dose ropivacaine provides effective analgesia during labour via the intrathecal route. It can be mixed with sufentanil in the above-mentioned concentrations to improve both the quality and duration of analgesia. Fetal outcome remains favourable. It may provide minimal or no motor block, to facilitate ambulation.     

瑞芬太尼用于产妇静脉自控镇痛分娩进展

瑞芬太尼具有起效快、时量半衰期短而恒定的药动学特点,是短时间、间断性分娩镇痛的理想药物.现在已有一些关于瑞芬太尼分娩镇痛的报道,报道认为瑞芬太尼静脉自控镇痛能够提供有效的镇痛,具有副作用小、产妇满意度高的特点.     

Are women requiring unplanned intrapartum epidural analgesia different in a low-risk population?

We studied 645 full-term low-risk women in early labour in 6 units to evaluate the effects of maternal characteristics and obstetric management in early labour on the use of epidural analgesia, and to analyse the relationship between epidural analgesia, progress of labour and mode of delivery using multiple logistic regression. Among variables present in early labour, nulliparity, ethnicity and obstetric unit were the strongest predictors of epidural analgesia requirement. In nulliparous women, obstetric unit affected use of epidural analgesia (P<0.05) and induction of labour was associated with increased use of epidural analgesia (odds ratio 3.45, 95% CI: 1.45-7.90). In multiparous women, only ethnicity was statistically significant (P<0.05). Epidural analgesia was associated with longer labours and more instrumental deliveries (odds ratio 2.93, 95%CI: 1.48-5.83). In the epidural group, however, we found a positive correlation between first stage duration and elapsed time before epidural analgesia. Furthermore, rate of cervical dilation was similar in the non epidural group throughout the first stage (mean 3.41 cm/h, 95%CI: 3.19-3.63) and in the epidural group after epidural analgesia decision (mean 3.99, 95% CI: 2.96-5.02), while the mean cervical dilatation rate before epidural analgesia was 0.88 cm/h (95% CI: 0.72-1.04). The need for epidural analgesia is, therefore, multifactorial and difficult to predict. Whereas nulliparity increases epidural analgesia requirement, data on the progress of labour before pain relief suggest that epidural analgesia is a marker of pain severity and/or labour failure rather than the cause of delayed progress in low-risk pregnancies.     

A comparison of pethidine and remifentanil patient-controlled analgesia in labour

We conducted a double-blind randomised controlled trial comparing the efficacy of analgesia during labour of remifentanil and pethidine. Nine women were randomised to receive an i.v. bolus of remifentanil 0.5 microg.kg(-1)with a lockout period of 2 min and eight women were randomised to receive a bolus of pethidine 10 mg with a lockout period of 5 min. A visual analogue scale (VAS) scoring system was used to assess the level of pain hourly throughout the first and second stages of labour and a score was recorded within half an hour of delivery for the level of pain overall throughout labour (post delivery score). The study was terminated after 17 subjects, on agreement with the local ethics committee, due to concern with the poor Apgar scores in the pethidine group. With the data available, we demonstrated significantly lower mean hourly and post delivery VAS scores for pain in the remifentanil group (P < 0.05). The 1 and 5 min Apgar scores were significantly lower in the pethidine group compared with the remifentanil group (P < 0.05). This preliminary study suggests that remifentanil may have a use as patient-controlled analgesia for women in labour.     

Respiratory arrest in an obstetric patient using remifentanil patient-controlled analgesia

Remifentanil patient-controlled analgesia is well established in many centres and provides satisfactory pain relief for many women in labour. We describe a patient using remifentanil patient-controlled analgesia who suffered a respiratory arrest requiring a brief period of ventilation. In our institution, remifentanil patient-controlled analgesia has been offered to women in labour since 2009. Up to this point, we had not observed any critical incidents in over 130 patients using this mode of analgesia in our labour suite.     

Analgesia in labour: induction and maintenance

Labour epidural analgesia underwent marked changes from the mid 1980s to the 1990s. The addition of opioids, such as fentanyl, to local anaesthetic reduced motor block and improved analgesia and maternal satisfaction. The introduction of new techniques such as combined spinal epidural analgesia and patient-controlled epidural analgesia further enhanced regional techniques. Dense motor block, historically associated with labour epidural analgesia, has now been reduced to a level where some mothers can choose to mobilize safely out of bed during their labour. In the past decade, research has focused on finding the ideal technique and combination of drugs to provide reliable analgesia with minimal motor block. No one technique has become universally popular, and the introduction of the new levo or s- enantiomer local anaesthetic has not had a major impact on labour analgesia practice. Currently, women can enjoy safe, reliable epidurals for labour analgesia with reduced or minimal motor blockade. The decisions are based on two decades of published research.     

Uterine rupture and epidural analgesia during trial of labour

A case of complete uterine rupture during a trial of labour in which epidural analgesia was used is described. The pain of uterine rupture was not masked by the addition of fentanyl 25 μg to bupivacaine 0.25% 6 ml but was relieved by bupivacaine 0.375% 6 ml.     

Epidural analgesia for labour and delivery in a parturient with congenital hypertrophic obstructive cardiomyopathy

We report a parturient delivering vaginally at term with symptomatic congenital hypertrophic obstructive cardiomyopathy. Epidural analgesia was used during labour and delivery and is likely to have made a useful contribution to the successful outcome. Although controversial, reported use of epidural analgesia during labour for hypertrophic obstructive cardiomyopathy parturients has been generally positive. A multi-disciplinary team approach, early anaesthetic assessment and a carefully managed epidural catheter inserted in early labour can optimize analgesia and minimize the stresses of labour and vaginal delivery provided the risks of reduced preload and afterload are minimized.     

Combined spinal epidural analgesia is the preferred technique for labour analgesia

To justify its place as the preferred method of pain relief in labour, CSE must demonstrated a clear superiority over epidural analgesia. Looking at the relative efficacy of the two techniques failure rates appear to be equal. Speed of onset may be faster with an initial spinal injection although perhaps only clinically relevant in advanced labour where the quality of analgesia may sometimes be better. CSE would not seem to offer significant advantage in terms of mode of delivery or the ability to ambulate. The side effects of the technique are somewhat more concerning as CSE would appear to carry slightly greater risk than epidural analgesia, most notably in neurological sequelae and the effects of intrathecal opioids. Certainly CSE confers no benefit in terms of cost. What then is the place of CSE in labour analgesia? Its potential benefit makes it a reasonable option when there is a clear clinical advantage such as requests for analgesia in late labour or where maternal distress is extreme or where epidural analgesia has been ineffective. However even in such situations the slight increase in risk must be weighed against the possible advantage. Consequently the CSE cannot at the present time be recommended as the preferred option for labour analgesia.     

SINGLE SPACE COMBINED SPINAL-EXTRADURAL TECHNIQUE FOR ANALGESIA IN LABOUR

We have used the single space combined spinal-extradural techniquefor mothers requesting analgesia in labour. Intrathecal plainbupivacaine 5 mg produced a median time to analgesia of 3 min.There was inadequate abdominal analgesia after 10min in 16%of recipients, although all had good perineal analgesia. Themedian height of block was T8 (range T4-L2) and mean durationof analgesia 72 (SD 21) min. Hypotension occurred in two of30 mothers, but responded to fluids and ephedrine. There wereno post-spinal headaches. This technique is suitable for thoseparturients requesting analgesia in active labour who may nothave time to achieve extradural analgesia before delivery. Theextradural catheter is used to improve analgesia if the subarachnoidblock is inadequate, or if labour continues beyond the durationof the subarachnoid block. (Br. J. Anaesth. 1993; 71: 499–502)     

Epidural catheter migration during labour: an hypothesis for inadequate analgesia

The purpose of this study was to determine the incidence and factors associated with poor analgesia during epidural block for labour pain. Emphasis was placed on determining the incidence, magnitude and factors associated with epidural catheter migration as well as any relationship between catheter migration and the quality of analgesia. Catheter movement was assessed, prospectively, in 211 consecutive parturients who had an epidural catheter placed for labour analgesia. The magnitude and direction of catheter movement was assessed by measurement of the length of the catheter at the skin at the time of epidural placement, and immediately before removal of the catheter, after delivery. Fifty-four per cent of the catheters migrated during labour and 70 per cent of these migrated out of the epidural space. The quality of analgesia provided by the epidural block was assessed by the caseroom nurse caring for the patient. Seventeen per cent of the patients had unsatisfactory analgesia. There was an increase in poor analgesia in those patients whose catheters migrated compared with those in whom the catheters were stable (P less than 0.05). We conclude that catheter migration during labour results in a greater incidence of inadequate block and unsatisfactory analgesia.     

Second stage of labour with or without extradural analgesia

Two groups of parturients who had received selective extradural analgesia were studied. In Group A patients the regional block was allowed to wear off for the second stage of labour whereas in Group B patients' analgesia was maintained throughout labour. The maintenance of selective analgesia was of positive benefit to the mothers. They experienced much less pain, labour was not prolonged, dosage of bupivacaine was not increased, the forceps delivery rate was lower and there were fewer persistent malrotations.