A randomized, double blind, placebo-controlled study to investigate the use of conscious sedation in conjunction with paracervical block for reducing pain in termination of first trimester pregnancy by suction evacuation

C.Y.G. Wong,1, E.H.Y. Ng, S.W. Ngai and P.C. Ho

Department of Obstetrics and Gynaecology, Queen Mary Hospital, University of Hong Kong, Hong Kong, China


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
BACKGROUND: This study evaluated the role of conscious sedation in pain relief during termination of first trimester pregnancy by suction evacuation (SE) under local anaesthesia. METHODS: A hundred women undergoing SE before 12 weeks gestation were randomized by computer using the sealed envelope method to receive placebo (saline) or conscious sedation (2 mg midazolam and 25 µg fentanyl) i.v. 5 min before cervical dilatation. Paracervical block was given to all patients, 2 min later. Pain scores during and after SE, post-operative side-effects and satisfaction level were compared. RESULTS: No statistically significant differences in pain scores were found between the two groups. Post-operative side-effects such as dizziness (P = 0.015) and drowsiness (P < 0.001) were significantly more severe in the conscious sedation group. However, patients in the conscious sedation group reported better satisfaction levels than the control group (P = 0.003). CONCLUSION: The use of conscious sedation significantly improved patient satisfaction during termination of first trimester pregnancy by SE under local anaesthesia, despite a lack of improvement in pain relief and the presence of increased severe dizziness/drowsiness in the post-operative period.

Key words: conscious sedation/pain relief/paracervical block/suction evacuation/termination of pregnancy


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Termination of first trimester pregnancy by suction evacuation (SE) is a common gynaecological procedure. The majority of such procedures were previously done under general anaesthesia. However, because of the cost and the potential complications associated with general anaesthesia, there is a move towards the use of local anaesthesia in therapeutic abortions (World Health Organization, 1978Go; Royal College of Obstretricians and Gynaecologists, 2000Go).

Paracervical block using a local anaesthetic such as lignocaine is the commonest form of local anaesthesia used in suction termination of pregnancy. However, 97% of the women experienced pain during abortion (Belanger et al., 1989Go). Therefore, additional means for reducing pain in termination of first trimester pregnancy are being explored.

Conscious sedation is achieved by concomitant administration of i.v. tranquilizers and i.v. narcotics to produce a state of depressed consciousness, which will facilitate the performance of diagnostic and therapeutic procedures. It is easy to administer and side-effects associated with the use of conscious sedation are well tolerated by the majority of the day-case patients. Conscious sedation has been shown by studies to be safe and useful in pain control for oocyte retrieval during assisted reproduction treatment (Trout et al., 1998Go; Ng et al., 2001Go). Its role in pain relief during SE for first trimester termination of pregnancy under local anaesthesia is still unclear. There was little information in the literature regarding this aspect. A non-randomized study (Rawling and Wiebe, 1998Go), showed no significant reduction of pain score after the use of conscious sedation. This study compared the pain control achieved by those clinics that offer conscious sedation with those which did not. Selection bias was likely to be present since only clinics agreeing to enter the study were recruited and different clinics used different regimens for sedation.

The aim of this randomized, double-blind and placebo-controlled study is to assess the role of conscious sedation in pain control during termination of first trimester pregnancy by SE under local anaesthesia.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Protocol
Women attending the Queen Mary Hospital for termination of pregnancy were recruited when the following criteria were met: (i) age of women >16 years; (ii) normal general and gynaecological examination; (iii) <12 weeks gestation on the day of recruitment and (iv) the size of the uterus on pelvic examination was compatible with the estimated duration of pregnancy. Those with a history of severe and recurrent liver disease, myasthenia gravis, psychiatric conditions requiring medication or disorders which constitute contraindications to the use of prostaglandins were excluded. Every patient was extensively counselled by a project nurse and gave their written informed consent prior to participating in the study, which was approved by the Ethics Committee of the Queen Mary Hospital, Hong Kong.

Prior to SE, prophylactic antibiotics were given because of the prevalence of Chlamydia infection in our population and misoprostol (Cytotec, Zuellig Pharma, Hong Kong) 400 µg was given vaginally 3 to 6 hours for cervical priming (Ngai et al., 1999Go).

Assignment
Patients were randomized into the placebo and conscious sedation groups according to the randomization list which was generated by computer in blocks of 10 and put in opaque envelopes. The theatre nurse not involved in the assessment of pain scores prepared the drug/placebo for i.v. In the placebo group, 2 ml of saline was given intravenously 5 min prior to cervical dilatation whereas 2 mg midazolam (Roche, Basel, Switzerland) and 25 µg fentanyl (Faulding Pharmaceuticals, Paramus, New Jersey, USA) were given i.v. to the conscious sedation group. Two minutes later, all patients had a paracervical block using 10 ml of 1% lignocaine (Weimer Pharma, Rastatt, Germany) at the 4 and 8 o'clock positions of the cervix.

Masking
Both the patient and the surgeon were blinded to the i.v. medication given by the theatre nurse. The cervix was dilated to Hegar dilator number 8–10 if necessary and SEs were performed by experienced surgeons using Karmen catheter number 8–10 depending on the size of the uterus. Vital signs including blood pressure, pulse, oxygen saturation and respiratory rate of the patients were closely monitored during the operation. The need for additional analgesia (i.m. pethidine) was recorded. The surgeon graded the level of sedation achieved during the operation according to a sedation scale proposed by Ramsay et al. (level 1: patient anxious and agitated or restless or both; level 2: patient co-operative, orientated and tranquil; level 3: patient responds to commands only; level 4: asleep and a brisk response to loud auditory stimulus; level 5: asleep and a sluggish response to loud auditory stimulus; level 6: asleep and no response to loud auditory stimulus) (Ramsay et al., 1974Go). Patients were asked by another theatre nurse not involved in the preparation of the drugs or placebo to rate the pain in verbal analogue scale from 0–10 (0 = no pain; 10 = intolerable pain) during insertion of an intravenous catheter, SE, and 5 min and 1 h after SE. The severity (none, mild, moderate and severe) of post-operative side-effects including nausea, vomiting, dizziness and drowsiness and the satisfaction level (excellent, satisfactory, fair and unsatisfactory) were also recorded prior to discharge from the hospital (usually 4 h after SE).

Statistical analysis
Comparisons of categorical variables between conscious sedation and placebo groups were made using the {chi}2-test. For continuous variables, the Mann–Whitney test was used to compare differences between groups. Multiple regression analysis was applied to evaluate the impact of the age of the women, parity (multiparous/nulliparous), gestational age and the sedation scale on the pain level during SE. Sample size calculation was performed using the previously described method (Meinert, 1986Go). Assuming that a difference in mean pain score between the placebo and conscious sedation groups of 1.5 was clinically significant and the standard deviation was 2.5 (Ng et al., 1999Go), 45 patients were required in each arm to achieve a power of 0.8 and a type I error of 0.05. Allowing that 10% of the data might be retrospectively excluded either due to incomplete data entry or violation of protocol, the number was 50 in each group. Thus, the total required sample size was 100.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Participant flow
A total of 100 consecutive patients were recruited from September to December 1999. All patients followed the study protocol and were available for analysis.

Analysis
There were no statistically significant differences in the age, gestational age and previous abortion history between the conscious sedation group and the control group (Table 1Go). However, 70% of the patients in the placebo group were multiparous versus 42% in the conscious sedation group (P = 0.005, {chi}2-test) despite randomization. Three patients in the conscious sedation group and one patient in the placebo group received additional analgesics (75 mg i.m. pethidine) and the difference was not statistically significant.


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Table I. Demographic data of patients undergoing suction evacuation under paracervical block
 
Table IIGo summarizes the sedation scale, pain scores and satisfaction levels. No significant difference was found in the distribution of the sedation level with approximately two-thirds of patients in each group being classified as level II. Pain levels during insertion of an i.v. catheter during and after SE were similar between the two groups. The satisfaction level was significantly better in the conscious sedation than the placebo group (P = 0 .003, {chi}2-test). The severity of post-operative side-effects are given in Figure IGo. Dizziness (P = 0.015, {chi}2-test) and drowsiness (P < 0.001, {chi}2-test) were significantly more severe in the conscious sedation group than in the placebo group.


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Table II. Sedation scale, pain scores and satisfaction scores of patients undergoing suction evacuation under paracervical block
 


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Figure 1. Post-operative side-effects between the placebo group and the sedation group.

 
Using stepwise multiple regression analysis, the two significant factors affecting the pain levels during SE were sedation scale (B: –0.971, ß: –0.261, P = 0.008) and gestational age (B: 0.572, ß: 0.220, P = 0.024). Age of women and parity (multiparous/nulliparous) were not found to affect these pain levels.


    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Although medical abortion is a possible option for management of first trimester termination of pregnancy, surgical management remained the mainstay in our locality due to the unavailability of mifepristone for abortion. This is the first randomized, double-blind, placebo-controlled trial addressing the use of conscious sedation for pain relief, in first trimester termination of pregnancy by SE. A previous non-randomized study had shown that there was no difference in the pain score after the use of conscious sedation (Rawling and Wiebe, 1998Go). Our study also failed to demonstrate any statistically significant differences in pain scores between the conscious sedation group and the placebo group.

Although a higher number of patients experienced severe post-operative side-effects in the conscious sedation group, the satisfaction score was significantly higher in this group in comparison with that of the placebo group. This unexpected result may be related to sedative, anxiolytic and amnesic effect associated with the use of conscious sedation. The environment of the operating theatre, the personnel involved and the sense of uncertainty and insecurity can lead to excessive anxiety. The sedative and anxiolytic effect of conscious sedation may help to reduce anxiety and therefore improve the satisfaction of patients undergoing SE. The amnesic effect of midazolam (Reader and Break, 1987Go) also helps the patient to forget the unpleasant feelings associated with the operation. This would also improve the overall patient's satisfaction.

Response to pain can be modified by past experience such as parity and history of previous SE. More multiparous women were found in the placebo group than the conscious sedation group and this difference was statistically significant. The stepwise multiple regression analysis revealed that only the sedation scale and the gestational age were significant factors affecting pain levels during SE. The uneven distribution of parity in this study would not affect the therapeutic effect of conscious sedation, if any.

The lack of difference in pain score between the two groups may be related to the small dosage of fentanyl used in this study. The recommended dose of fentanyl is 1 µg/kg body weight when used alone, but the dosage should be reduced when used in conjunction with other sedatives. (Evangelista, 2000/2001Go) Therefore, a smaller dosage of fentanyl was used in this study in order to avoid complications such as respiratory depression, bradycardia and hypotension. As the analgesic requirement for different individuals can be different, one way to overcome such a problem is to titrate the amount of analgesic given according to the patient's pain response. However, SE is a minor procedure and the operative time is short. Therefore, in practice, it would be difficult to achieve the optimal dosage by this titration method.

Conscious sedation seems to be safe as none of the patients in this study suffered from significant adverse effects and all of them could be discharged as day-patients. This has a significant impact on the cost of the health care system. In places where the anaesthetic facilities are tight or the cost is high, the use of conscious sedation is a good alternative for patients who are afraid of the procedure being performed under local anaesthesia alone. Future studies should be done to determine the optimal dosage of analgesia and sedative used for pain relief during SE.

In conclusion, patients undergoing first trimester termination of pregnancy by SE under local anaesthesia experienced similar levels of pain during the procedure and within 1 h after the procedure, regardless of whether conscious sedation was given or not. Those receiving conscious sedation had more severe dizziness/drowsiness but they reported a higher satisfaction score when compared with those receiving placebo only.


    Notes
 
1 Department of Obstetrics & Gynaecology, 6/F Professorial Block, Queen Mary Hospital, Pokfulam Road, Hong Kong, China. E-mail: wongcyg{at}yahoo.com Back


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Belanger, E., Melzack, R. and Lauzon, P. (1989) Pain of first trimester abortion: a study of psychosocial and medical predictors. Pain, 36, 339–350.[ISI][Medline]

Evangelista, L.F. (ed.) (2000/2001) MIMS Annual Hong Kong. Havas Medi, Asia Ptd Ltd., Singapore, pp. 432–433.

Meinert, C.L. (1986) Sample size and power estimates. In Meinert, C.L. and Tonascia, S. (eds) Clinical Trials: Design, Conduct and Analysis. Oxford University Press, Oxford, UK pp 71–88.

Ng, E.H.Y., Tang, O.S., Chui, D.K.C. et al., (1999) A prospective, randomized, double blind and placebo controlled study to assess the efficacy of paracervical block in the pain relief during egg collection. Hum. Reprod., 14, 2783–2787.[Abstract/Free Full Text]

Ng, E.H., Chui, D.K., Tang, O.S. and Ho, P.C. (2001) Paracervical block with and without conscious sedation: a comparison of the pain levels during egg collection and the postoperative side effects. Fertil. Steril., 75, 711–717.[ISI][Medline]

Ngai, S.W., Chan, Y.M., Tang, O.S. and Ho, P.C. (1999) The use of misoprostol for pre-operative cervical dilatation prior to vacuum aspiration: a randomised trial. Hum. Reprod., 14, 2139–2142.[Abstract/Free Full Text]

Ramsay, M.A., Savege, T.M., Simpson, B.R. and Goodwin, R. (1974) Controlled sedation with alphaxalone alphadolone. Br. Med. J., 920, 656–659.

Rawling, M.J. and Wiebe, E.R. (1998) Pain control in abortion clinics. Int. J. Gynecol. Obstet., 60, 293–295.[ISI][Medline]

Royal College of Obstetricians and Gynaecologists (2000) Evidence-based Clinical Guidelines No. 7, The Care of Women Requesting Induced Abortion. RCOG Press, London, UK, 39pp.

Reader, J.C. and Break, H. (1987) Premedication with midazolam in outpatient general anaesthesia. A comparison with morphine, scopolamine and placebo. Acta Anaesthesiol. Scand., 31, 509–514.[ISI][Medline]

Trout, S.W., Vallerand, A.H., Kemmann, E. (1998) Conscious sedation for in vitro fertilization. Fertil. Steril., 69, 799–808.[ISI][Medline]

World Health Organization (1978) Induced Abortion Technical report no. 22, 623, Geneva, Switzerland.

Submitted on July 25, 2001; accepted on January 4, 2002.





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