A study to compare the efficiency of bupivacaine and bupivacaine with clonidine in reducing the pain during labour

 

 

Abstract               Background: Epidural analgesia is widely considered as the most effective method of providing pain relief in labour4. However, epidural labour analgesia is not a generic procedure and many technical modifications have been invented over time. Continuous search for balanced labour analgesia, which provides relief of pain of contractions while preserving motor functions, has led to the development of ambulatory labour analgesia. Objective: To compare the efficacy of the drugs – Bupivacaine vs Bupivacaine and Clonidine in reducing the pain during the labour process. Methodology: A prospective study was conducted at Sholapur Medical College during the period from November 2011 to October 2013 at Department of OBG, Sholapur Medical College, Sholarapur. A total of 100 study subjects who were healthy term parturients, admitted in the labour ward of the hospital with ASA grade I and II aged 20-35 years in active labour with minimum 3cm dilatation of cervix with cephalic presentation and singleton pregnancy were selected for labour analgesia. They were divided in two groups randomly. Group A (n=50) received Bupivacaine 0.125% alone Group B (n=50) received Bupivacaine 0.125% along with Clonidine 60 microgram. Results: Total duration of labour was 247.5 + 58.11 minutes in Group A and 228.4 + 35.76 minutes in Group B. The total Duration of action of analgesia in Group A is 46.36 + 11.92 minutes and 102.88 + 12.4 minutes in Group B and the association was found to be statistically highly significant. After injection of the drug, VAS score in Group A reached </= to 3 at 15th minute in Group A and at 10th minute in Group B i.e., earlier in Group B and it is statistically significant after the first five minutes. Conclusion: Clonidine when added as adjuvant to local anaesthetics in Epidural labour analgesia prolongs the duration of analgesia. Total top up doses required when Clonidine was added s adjuvant in Epidural analgesia is less. From above study we conclude that Clonidine is a useful adjunct to Bupivacaine for epidural labour analgesia and can be considered as alternative to opioids.

Keywords: Clonidine, Bupivaccine, Labour, Anasthesia, Pain.

 

INTRODUCTION

Giving birth is a painful process. This applies to all societies and ethnic group and has probably been since mankind walked upright. It is difficult to measure pain which is recognized via the signals carried through nervous system and women intellectual response to stimuli. Various methods have been tried since time immemorial to alleviate this pain. However, this endeavor did not receive much support till the late 19^th century with analgesia for labour being opposed for both medical and religious reasons. It was also believed that pain had a biological value and attempts to abolish it would be detrimental to both mother and foetus. However, the recognition of various physiological disturbances that can occur due to unrelieved labour pain brought about a change in the thinking. In view of this, the concept of labour analgesia came to be widely accepted.¹ Historically, the era of obstetric anesthesia began with James Young Simpson when he administered ether to a woman with deformed pelvis during childbirth. His concept of ‘etherization of labour’ was strongly condemned by critics! There was religious debate over appropriateness of anaesthesia of labour². Labour analgesia was provided to Queen Victoria by John Snow for the birth of Prince Leopold in 1853 with the use of chloroform during her eighth confinement and with this, the practise of limiting pain during labour gained immense acclaim³. Since then various methods of pain relief were tried out. Techniques such as parental opioids, inhalational agents and even other regional blocks are not widely accepted because of their ineffective, incomplete analgesia and due to their deleterious effect on mother and baby. With the advent of spinal anaesthesia the potential of regional block as the near ideal techniques in obstetrics was considered. But was later ruled out due to severe hypotension, dense motor blockade etc. Caudal analgesia was popular until benefits of epidural were noted. Epidural analgesia is widely considered as the most effective method of providing pain relief in labour⁴. However, epidural labour analgesia is not a generic procedure and many technical modifications have been invented over time. Continuous search for balanced labour analgesia, which provides relief of pain of contractions while preserving motor functions, has led to the development of ambulatory labour analgesia. Clonidine is an alpha2 adrenergic agonist that produces analgesia via a non-opioid mechanism, and the combination of epidural clonidine with Bupivacaine has been previously studied and has shown to have local sparing and analgesic effects thus prolonging the duration by local anaesthetic agents^5,6,7. We undertook this study to compare the effects of addition of clonidine to epidural Bupivacaine for labour analgesia with regard to various parameters .

 

OBJECTIVE

To compare the efficacy of the drugs – Bupivacaine vs Bupivacaine and Clonidine in reducing the pain during the labour process.
MATERIALS AND METHODS

A prospective study was conducted at Sholapur Medical College during the period from November 2011 to October 2013 at Department of OBG , Sholapur Medical College, Sholarapur. A total of 100 study subjects who were healthy term parturients, admitted in the labour ward of the hospital with ASA grade I and II aged 20-35 years in active labour with minimum 3cm dilatation of cervix with cephalic presentation and singleton pregnancy were selected for labour analgesia. They were divided in two groups randomly. Group A (n=50) received Bupivacaine 0.125% alone Group B (n=50) received Bupivacaine 0.125% along with Clonidine 60 microgram 10ml of 0.125% Bupivacaine / 0.125% Bupivacaine and Clonidine 60 mcg as first dose and further top ups of 5-7cc were given whenever VAS > 4 in parturients with Group A and Group B respectively. After admission to our hospital thorough medical, obstetric and anaesthetic history was taken which was later followed by a general and obstetric examination. Investigations like haemoglobin percentage, blood grouping and typing, urine analysis was done.

Exclusion criteria

1. For epidural anaesthesia
2. Patient refusal
3. Infection at the site of block
4. Sensitivity to anaesthetic drugs
5. Patient with bleeding disorder.
6. Obstetric criteria
7. Cephalopelvic disproportion
8. Eclampsia, Diabetes mellitus

The procedure plan was explained in their vernacular language and written informed consent was taken from the patient and reliable accompanying relative.

 

Methods of Data Collection:

Patients were asked to empty bladder before the procedure.Patient was then taken to the operation theatre. Pulse rate and blood pressure was recorded as a baseline reading. Intravenous cannula 18G or 20G was placed.Patients were preloaded with 20ml/kg of Ringer lactate solution.Acid prophylaxis in the form of Inj. Ranitidine 1mg/kg and Inj. Metaclopramide 0.2mg/kg was given. Patient monitored with NIBP, ECG and Pulse oximetry Under all asceptic precautions the equipments were placed on the trolley. Patient’s back was painted from T12 to the gluteal cleft and up to both the anterior superior iliac spine on the sides with 0.5% betadine solution and wiped off with spirit. Then the back was draped with sterile hole-towel. Tip of the anterior superior iliac spine was palpated and the corresponding L3-L4 or L4- L5 space was identified. 24G needle was used to obtain a wheal by injecting 2cc of 2% lignocaine in L3- L4 space. Track was formed with 18g hypodermic needle. Group A patients were administered with 10 cc of 0.125% Bupivacaine alone Group B patients were administered with 10 cc of 0.125% Bupivacaine along with 60mcg of Clonidine. Drugs were given through epidural catheter in graded doses checking for the response because no test dose was used. After the drug was injected to the parturients, they were monitored for Onset of analgesia – the time duration from drug injection to first painless contraction (VAS </3). Duration of analgesia – the time from onset of first painless contraction to the the first top up dose, Two segment recession time was noted. Foetal well being was assured by cardiotocogram. Pain scoring by VAS was recored. Our obstetric department standard protocol was followed for labour. Mode of delivery and time of delivery were noted. Assessment of neonatal welfare was observed with the help of Apgar scoring at 1min and 5min after delivery. After episiotomy epidural catheter was removed and catheter tip was checked. Assessment of pain relief – By visual analogue scale- Perception of pain relief is subjective and this variable was standardised by using data from Visual analogue scale. Visual Analogue scale involves the use of 10cm scale which was marked from 0-10. This was explained to the parturient that one end of the scale with red represents as much pain as much she can possibly imagine while the other end coloured green represents no pain at all. The subject rates the degree of pain by the colour on the visual analogue scale. Values are then obtained from the scale. The values were represented as mean + SD. For comparision between groups A and B, a students ‘t’ test and ‘z’ test was applied. Differences were considered statistically significant if p< 0.05.

 

RESULTS

A comparative study of Epidural labour analgesia is done between Group A (0.125% Bupivacaine alone) and Group B (0.125% Bupivacaine with 60mcg Clonidine). In our present study, fifty cases of each were randomly allocated. The mean age of the cases in group A was 23.82 years and Group B was 23.16 Years, the mean weight in group A was 56.12 kg and Group B was 56.04 Kgs. The weight , Age and Height were found to be statistically non significant between both the groups . In group A total of 33 were primigravida and 17 were multi gravida , where as in Group B a total of 34 were primiparous and 16 were multiparous. Parity was also found to be statistically non significant .

 

Table 1: Comparison of Characteristics of Analgesia in both the groups

Total duration of labour was 247.5 + 58.11 minutes in Group A and 228.4 + 35.76 minutes in Group B. The P value is 0.0506 which is more than 0.05 which is statistically insignificant. Total duration of labour is within normal limits in both the groups and is statistically insignificant. The total Duration of action of analgesia in Group A is 46.36 + 11.92 minutes and 102.88 + 12.4 minutes in Group B and the association was found to be statistically highly significant .The Onset of analgesia in Group A is 9.94 + 1.01 minutes and Group B is 9.7 + 8.14 minutes and the p value was found to be statistically non significant . The two segment recession time was 50.92 + 12.62 minutes in Group A and 108.86 + 12.30 minutes in Group B and the association was found to be statistically very significant.

 

Table 2: Total no. of top up doses in both the groups

The average number of top ups administered to Group B was 1.64 + 0.52 which is comparatively lesser number of top up doses than Group A which was 2.38 + 0.66. The P value was 1.57E – 08 (< 0.05) which was highly significant.

 

Table 3: Comparison of Visual Analogue Score in both the groups

After injection of the drug, VAS score in Group A reached </= to 3 at 15^th minute in Group A and at 10^th minute in Group B i.e., earlier in Group B and it is statistically significant after the first five minutes.

Table 4: Comparision of Sedation Score in both the Groups

In group A, Forty-seven parturients had sedation score 2 and three of them had sedation score 1. In Group B, forty-eight parturients had sedation score 2 and two of them had sedation score 3. Sedation score 2 is most acceptable, 96% parturients in Group A and 94% parturients in Group B had sedation score 2. The Association was found to be statistically non significant.

 

Table 5: Comparision of Maternal satisfaction regarding pain during labour in both the groups

 

Maternal satisfaction is more in Group B than Group A which is statistically significant. Excellent scores were given by 11(22%) parturients in Group A and 21(42%) parturients in Group B. Good score by 38 (64%) parturients in Group A and 28 (56%) parturients in Group B. Poor scores were given by 1(2%) parturients in Group A and 1 (2%) in Group B. Excellent and Good score is acceptable and considered success. It is 98% in Bupivacaine group and 100% in Bupivacaine + Clonidine group.

 

DISCUSSION

Labour is a painful process and there are no absolutely physiological advantages from labour pain. Indeed the labour pain results in suffering, marked maternal hyperventilation, increased work of breathing and increased oxygen demand. This natural response to pain results in higher levels of catecholamines resulting in uterine hypoperfusion, foetal hypoxia and acidosis. Various methods to overcome maternal and foetal stress have been tried to make childbirth free of pain. In our study the average age in both the groups were comparable even the height and weight were comparable in both the groups. But all these variables were found to be statistically non significant. The findings in our study were comparable to the study findings of to K.Syal et al⁸, O’Meara et al⁹. In our present study, onset of analgesia was confirmed by asking the parturient to scale the pain in Visual analogue scale in which VAS < / = 3 indicates onset of analgesia. Onset of analgesia in both the groups was comparable and statistically insignificant. The findings in our study was similar to the findings of K Syal et al ⁸, Chassard et al ⁶ and Claes B et al ¹⁰. But contradictory results were obtained by Landau R and co-workers et al¹¹ where addition of Clonidine to Ropivacaine led to earlier onset of analgesia, but their onset of analgesia was till maximum targeted pain relief. In our study onset of pain relief was till VAS </= 3. Duration of action was the duration from time of onset of action (VAS <3) to the time of requirement of first epidural top up. In our study, duration of analgesia was significantly prolonged in Group B (102.88 + 12.4minutes). It was 46.36 + 11.92 minutes in Group A which was comparable to Cigarini et al⁷, Claes B et al¹⁰ and K.Syal et al⁸. In study by K.Syal et al⁸, addition of Clonidine prolonged duration of analgesia (Clonidine group - 126min vs. Plain Bupivacaine - 97 min) and was statistically significant. These results are similar to studies where Clonidine was used as an adjuvant in other blocks as studied by Casati et al¹², El Saied A H et al¹³, De Kock M et al¹⁴ and De Negri P et al¹⁵ as well Epidural labour analgesia.

In our present study, total top up dose required in Group A was 2.38 + 0.66 and in Group B was 1.64 + 0.52. There was significantly lesser requirement of top up doses in Group B than Group A. Similar to our result studies by Cigarini et al⁷, Claes B et al¹⁰, K. Syal et al⁸, Landau R and co-workers¹¹ and Dewandre RY et al¹⁶ In our study, two segment recession time i.e,the time taken for the level of analgesia to recede by two spinal segments was noted. Two segment recession time was 50.92 + 12.62 minutes in Group A and 108.86 + 12.30 minutes in Group B. It is more prolonged in Clonidine group. P value was 1.202E-41 (<0.05) and hence was statistically highly significant. This result goes in with the analgesic and local anaesthetic sparing action of Clonidine Studies by Claes B et al¹⁰, Cigarini et al⁷ gave similar results.

Maternal satisfaction is more in Group B than Group A which is statistically significant. Excellent scores were given by 11(22%) parturients in Group A and 21(42%) parturients in Group B.Good score by 38 (64%) parturients in Group A and 28 (56%) parturients in Group B. Poor scores were given by 1(2%) parturients in Group A and 1 (2%) in Group B. According to study by K. Syal et al⁸ there was higher patient satisfaction scores in group II (8.36 vs 7.32 out of 10) which is expected as there was lower NRS scores and longer duration of analgesia due to clonidine. This was also found in other studies by Cigarini et al⁷, Claes et al¹⁰ and Landau R et al¹¹.

 

CONCLUSION

Clonidine when added as adjuvant to local anaesthetics in Epidural labour analgesia prolongs the duration of analgesia. Total top up doses required when Clonidine was added s adjuvant in Epidural analgesia is less. From above study we conclude that Clonidine is a useful adjunct to Bupivacaine for epidural labour analgesia and can be considered as alternative to opioids.

REFERENCES