Extradural Analgesia In Labour Research Articles

Double blind comparison of combination of 0.1% ropivacaine and fentanyl to combination of 0.1% bupivacaine and fentanyl for extradural analgesia in labour.

Background and Aims:Ropivacaine is considered as a safe alternative to bupivacaine for labor analgesia. The aim was to compare epidural ropivacaine and bupivacaine in intermittent doses for obstetric analgesia.Material and Methods:In this prospective, randomized, double-blind study, 60 women in labor were randomly allocated to receive either bupivacaine 0.1% with fentanyl 2 μg/mL (BF), or ropivacaine 0.1% with fentanyl 2 μg/mL (RF). Bromage scale, loss of cold sensation to ether swab in midclavicular line, visual analog scale were used to test for motor block, sensory block and pain, respectively. Hemodynamic parameters, onset of analgesia, dose requirement of drug to produce analgesia, duration of labor, and incidence of side effects were also recorded. Data were expressed as mean ± standard deviation and analyzed using students unpaired t-test, Chi-square and Mann-Whitney U-tests at P < 0.05.Results:Both drugs were similar with respect to hemodynamic stability, onset of analgesia, quality of analgesia, sensory blockade, neonatal outcome, requirement of drugs, duration of labor, and incidence of side effects. Three parturient in bupivacaine (B-F) group had a motor block of Bromage 1 and were delivered using forceps. None of the parturient in ropivacaine (R-F) group had any motor block, and all had spontaneous vaginal delivery, but this difference was not statistically significant (P = 0.081).Conclusions:Bupivacaine and ropivacaine provide equivalent analgesia in low (0.1%) concentration.

Initiating Extradural Analgesia during Labour: Comparison of Three Different Bupivacaine Concentrations Used as the Loading Dose

Objective: Potential effects of extradural analgesia on the progress of labour and obstetric outcome are still a matter of concern and the focus of ongoing debates. Despite this, little attention is paid to the initiation of extradural labour analgesia. The objective of this prospective, randomized, double-blind trial was to identify the optimal of three concentrations of bupivacaine used as a loading bolus for initiating extradural analgesia during labour. Methods: Sixty-seven full-term parturients requesting extradural analgesia received either bupivacaine 0.25% (group A), 0.125% (group B) or 0.0625% (group C). Bupivacaine administration was titrated to achieve a pain score ≤1.5 on a 10-cm visual analogue scale (VAS) and was limited to a maximum of 20 ml of the study drug. We recorded the time to achieve a VAS ≤1.5, the total amount of local anaesthetic used, sensory level, maternal and foetal as well as neonatal side effects. Results: The probability of obtaining a VAS pain score ≤1.5 was significantly lower in group C. Although mean times to reach a VAS pain score ≤1.5 were not statistically different, survival curves show a significantly lower probability for reaching this score. Significantly more parturients in group A developed a motor block ≥1 based on using a modified Bromage scoring scale. There were no differences in incidence of maternal hypotension, ephedrine requirements, foetal heart rate abnormalities, mode of delivery and neonatal outcome. Conclusions: Of the three concentrations used in this clinical setting, 0.125% was the most suitable concentration of plain bupivacaine to initiate extradural analgesia in labour. Using 0.25% bupivacaine increased the incidence of motor block, whereas for 0.0625% plain bupivacaine the probability to achieve adequate analgesia was unacceptably low.

Pharmacokinetic and clinical study of ropivacaine and bupivacaine in women receiving extradural analgesia in labour

We have compared, in a randomized, double-blind study, the pharmacokinetics of ropivacaine and bupivacaine during labour. Total and free plasma concentrations of ropivacaine and bupivacaine were measured after the first of two extradural doses. The main dose was 20 mg (test dose) and 30 mg, with a top-up dose of 25 mg when requested. After the main dose, Cpmax (total) of ropivacaine (0.50 mg litre-1) was similar to that of bupivacaine (0.48 mg litre-1). At 20 min, Cpmax (free) of ropivacaine (0.04 mg litre-1) was higher than that of bupivacaine (0.02 mg litre-1) (P = 0.0025). The clinical effectiveness of the block was similar in both groups.

A.329 Obstetric cause for unblocked segments in extradural analgesia for labour

A.329 Obstetric cause for unblocked segments in extradural analgesia for labour

A.325 Evaluation of extradural analgesia for labour by the parturient vs by the anaesthesiologist

A.325 Evaluation of extradural analgesia for labour by the parturient vs by the anaesthesiologist

Extradural analgesia with clonidine and fentanyl compared with 0.25% bupivacaine in the first stage of labour

Conventional extradural analgesia during labour with 0.25-0.375% bupivacaine may induce motor weakness and subjective sensory deficit, reducing maternal satisfaction. Even in a regimen for ambulatory extradural analgesia (0.1% bupivacaine-fentanyl 2 micrograms ml-1), a potential for proprioreception impairment exists, which may impair safe ambulation. We have combined fentanyl with clonidine for extradural analgesia in labour, and compared its effects with 0.25% bupivacaine, in a randomized, double-blind study. We studied 28 women requesting extradural analgesia for labour; they were allocated randomly to either group 1, who received clonidine 120 micrograms with fentanyl 50 micrograms, or group 2, who received bupivacaine 25 mg. Detailed clinical neurological examination was undertaken 30 min later. Pain was assessed subjectively using a 10-cm visual analogue scale (VAS). There were no significant differences in VAS between the groups at any time. Median onset of analgesia was longer in group 1 (24.3 (interquartile range 20-35) compared with 17.5 (15-25) min) (P < 0.05) and 79% of group 1 vs 86% of group 2 patients reported a high degree of satisfaction with extradural analgesia. Patients in group 2 had a much higher incidence of motor weakness (P < 0.01), impaired perception of pinprick (P < 0.01) and impaired distal joint proprioception (P < 0.05) than group 1. We conclude that clonidine 120 micrograms-fentanyl 50 micrograms provided comparable extradural analgesic efficacy as 0.25% bupivacaine for the first stage of labour. Furthermore, unwanted neurological effects were significantly less.

A double-blind comparison of 0.25% ropivacaine and 0.25% bupivacaine for extradural analgesia in labour

Ropivacaine is a new aminoamide local anaesthetic. Compared with bupivacaine, ropivacaine possesses a higher threshold for systemic toxicity and a high selectivity for sensory fibres. We have compared prospectively these two agents in a concentration of 0.25% for extradural analgesia in labour. A total of 104 parturients requesting extradural analgesia were randomized to receive either ropivacaine or bupivacaine. The women in the bupivacaine group required more top-up doses to maintain analgesia (median 3.0 vs 2.0) (P < 0.05). The onset of sensory block, quality of analgesia, ultimate level of maximum sensory block and maternal satisfaction were similar in both groups. The incidence, intensity and duration of motor block were slightly but not significantly less in the ropivacaine group. The ropivacaine group had a higher incidence of spontaneous vaginal delivery (70.59% vs 52.00%). There was no significant difference in neonatal outcome as assessed by Apgar scores, umbilical acid-base status and neurological and adaptive capacity score at 2 and 24 h after delivery. We conclude that ropivacaine and bupivacaine in a concentration of 0.25% produced comparable analgesia for pain relief of labour with no detectable adverse effect on the neonate.

The space blanket and shivering during extradural analgesia in labour

The incidence of shivering in women during epidural analgesia in labour is up to 33%, and may be highly distressing. Its mechanism is unclear, but the most widely held theory is that it is thermogenic. Pharmacological suppression may adversely effect the foetus or induce maternal hypothermia, and although physical remedies such as direct heat application are effective, they are also expensive and cumbersome. We recently found that the space blanket, a simple aluminised metallic foil, used pre-emptively, reduces shivering after general anaesthesia. We investigated the effect of the space blanket on the incidence and intensity of shivering, axilliary skin temperature, and subjective perception of cold during epidural analgesia for labour in 50 women over a four-hour time frame. Patients were randomised into group 1, who were wrapped in a space blanket immediately after commencement of epidural analgesia with bupivacaine, and group 2 (matched controls). Shivering was defined as visible tremor of the head, neck, trunk or limbs as observed by the attending midwives. Twenty-nine percent of group 1 and 35% of group 2 shivered (not significant), but a reduction in shivering intensity was observed in group 1 (P < 0.05). There was no significant difference in skin temperatures in either group, and no significant temperature change within the groups. Both groups had similar thermal comfort scores throughout the study, which correlated poorly with the presence of shivering. We conclude that there is no benefit in application of the space blanket to reduce epidural-analgesia related shivering in labour, which may indicate a non-thermogenic mechanism for this phenomenon.

Extradural analgesia in labour: complications of three techniques of administration

We have studied the complications associated with three techniques used to maintain extradural analgesia in labour: midwife top-up doses of 0.25% bupivacaine 10 ml, continuous infusion of 0.125% bupivacaine 10 ml h-1 and patient-controlled extradural analgesia (PCEA) with self-administered 3-ml bolus doses of 0.25% bupivacaine. A significantly higher intervention rate by an anaesthetist was required in the continuous infusion group. There was no difference in the mode of delivery between the three groups, although some women in the continuous infusion group had significantly denser motor block. There was a similar incidence of rectal pressure, unilateral block and missed segments in the three groups. Uneventful hypotension occurred in three women; two receiving PCEA and one receiving continuous infusion. Ten women experienced sensory blocks extending above T7 with no ill effects; seven receiving PCEA and three continuous infusion.

Posterior column sensory impairment during ambulatory extradural analgesia in labour

Ambulatory or "walking" extradural analgesia in labour has recently gained popularity because of preservation of motor function and subjective somatic sensation in the lower limbs, resulting in increased maternal satisfaction. This is produced by combining dilute concentrations (e.g. 0.1%) of bupivacaine with opioids. Detailed clinical neurological examination after mobile extradural analgesia has not been reported. We have investigated the effect of 0.1% bupivacaine 15 ml and fentanyl 2 micrograms ml-1 on motor and sensory function in the lower limbs in 50 primigravidae requesting extradural analgesia in labour. This was performed before and 30 min after confirming placement of a lumbar extradural catheter. While power, co-ordination and reflexes in all lower limb muscle groups remained within normal limits, 66% (n = 33) developed abnormal distal proprioception, 44% (n = 22) had a positive Romberg's sign and 38% (n = 19) had altered vibration sense. Moreover, 44% (n = 22) said that their legs felt different on standing and they did not feel confident walking unaccompanied. However, this subjective perception correlated poorly with the presence of posterior column sensory signs. Although there was a reduction in pain scores on a visual analogue scale after 30 min (mean 8.85 (SEM 0.3) vs 3.06 (0.32); P < 0.0001), pain increased within 60 min (5.77 (0.45); P < 0.001).

Maternal Temperature Regulation During Extradural Analgesia for Labour

We have studied the effect of analgesia on maternal temperature (oral and tympanic membrane) progression in 53 women during normal spontaneous labour. Three groups were studied: two received extradural analgesia with a continuous infusion of 0.25% bupivacaine with or without the addition of fentanyl; the third group received only parenteral opioid analgesia. All patients were afebrile and without clinical evidence of infection at the beginning of the study. Both groups of patients receiving extradural analgesia had a consistent and significant increase in temperature after approximately 5 h of analgesia; no such trend was observed in the parenteral opioid group. Alterations in mechanisms of heat dissipation may explain these findings.

RUPTURE OF MEMBRANES BEFORE THE ONSET OF SPONTANEOUS LABOUR INCREASES THE LIKELIHOOD OF INSTRUMENTAL DELIVERY

We studied obstetric outcome in 350 consecutive nulliparous women in spontaneous labour and term pregnancy. Women who presented with rupture of membranes before the onset of contractions were more likely to deliver by forceps compared with those in whom contractions preceded rupture of membranes. This increased likelihood of instrumental delivery was significant with and without the use of extradural analgesia in labour (P less than 0.05 and P less than 0.001, respectively). Furthermore, significantly more women with premature rupture of membranes received extradural analgesia in labour (P less than 0.01). We conclude that any study which aims to examine the influence of extradural analgesia on the outcome of delivery should include premature rupture of membranes as a bias factor.

COMPARATIVE STUDY OF THE EFFECTS OF AIR OR SALINE TO IDENTIFY THE EXTRADURAL SPACE

Fifty women in labour were allocated randomly to receive either air or saline to assist in the identification of the extradural space by the loss of resistance technique. A study volume of 4 ml of air or saline was used before 0.5% bupivacaine 8 ml and the spread of analgesia was followed for 30 min. The first segment blocked, time of onset, number of blocked segments and height of block were comparable in the two groups. At 30 min, there were eight patients with an unblocked segment in the air group, compared with two in the saline group (P less than 0.01). All unblocked segments were blocked subsequently by further doses of bupivacaine. We conclude that air is more likely than saline to produce unblocked segments in the initiation of extradural analgesia in labour.

Effect of Adrenaline, Fentanyl and Warming of Injectate on Shivering following Extradural Analgesia in Labour

This prospective, controlled study was undertaken to determine whether addition of adrenaline or fentanyl to bupivacaine or warming of the injectate had any effect on the incidence of shivering following extradural analgesia in the labouring parturient. Eighty-four patients were sequentially allocated to four groups (control, warm injectate, extradural adrenaline and extradural fentanyl). The adrenaline group had the highest incidence of shivering, the warm injectate and fentanyl groups the lowest. Extradural fentanyl also seemed promising in reducing shivering in pre-block shiverers. This paper also explores the rapidity of temperature decay of solutions of bupivacaine in different clinical situations.

Comparison of Plasma Bupivacaine Concentrations During Continuous Extradural Infusion for Labour

Twenty patients who requested extradural analgesia for labour were allocated randomly to receive an infusion of either 0.25% or 0.08% solutions of bupivacaine. Following an initial bolus dose of 50 mg, the infusions were given at a rate of 20 mg h−1. Both solutions provided acceptable pain relief, but plasma concentrations were significantly lower with the weaker concentration.

Continuous Extradural Analgesia in Labour. Comparison Between “On Demand” and Regular “Top-up” Injections

Division of Anaesthesia and University Department of Anaesthesia, Glasgow Royal Infirmary, Glasgow, Scotland

CONTINUOUS EXTRADURAL ANALGESIA IN LABOUR: Comparison Between “On Demand” and Regular “Top-up” Injections

In a prospective comparative study 240 patients received extradural bupivacaine, either by regular timed injections or "on demand", for pain relief during the first stage of labour. Three concentrations of bupivacaine were used (0.5%, 0.375% and 0.25%). Quality and continuity of analgesia, motor blockade, spread of sensory blockade, cardiovascular changes, fetal outcome and maternal sequelae were recorded. Overall, the analgesia provided by regular top-up injections was superior to the on demand technique, especially when 0.375% bupivacaine was used. This improved analgesia was achieved without causing an increased incidence of operative deliveries or deleterious sequelae, with respect to the mother or the neonate.

Cervical surgical emphysema following extradural analgesia.

Summary Three patients requesting extradural analgesia for labour developed cervical emphysema. The extradural space was located by loss of resistance to injection of air. This complication has been reported before and means of prevention are considered.

Posture and the Spread of Extradural Analgesia in Labour

Posture and the Spread of Extradural Analgesia in Labour

POSTURE AND THE SPREAD OF EXTRADURAL ANALGESIA IN LABOUR

Thirty-five patients kept in a sitting position for 5 min after a standard extradural injection in labour were compared with 54 patients maintained in the left lateral position throughout. The mean upper limit of analgesia was unchanged. A significant shift of the mean lower limit occurred in the sitting patients (P = 0.05, two-tailed), but contrary to classical teaching this was in a cephalad direction. Successful sacral blockade (analgesia at S234) and asymmetry of blockade occurred in a similar proportion of each group. It was concluded that the sitting position conferred no clinical advantage to patients receiving extradural analgesia in labour.