Reply to ‘Pain relief using electro-acupuncture for oocyte retrieval’
1 Department of Obstetrics and Gynecology, Department of Physiology and Institute of Occupational Therapy and Physiotherapy, Box 455, SE-405 30 Göteborg, Sweden 2 The Fertility Clinic, Skive Sygehus, DK 7800 Skive, Denmark
Email: elisabet.stener-victorin{at}fhs.gu.se
Sir,
We thank you for the opportunity to comment on Dr Rencken's letter and we are pleased that our paper sparked some debate.
Few topics in pain management are as controversial as acupuncture; the evidence seems to be split down the middle between positive and negative results. Proponents and opponents of acupuncture often do not seem to speak the same language and appear to keep missing each others' points. Interpretation of results is often difficult in acupuncture trials. In essence, proponents usually find fatal flaws in negative randomized controlled trials (RCTs) while opponents find the same in positive RCTs, thus opponents are likely to search for a conclusion other than ‘acupuncture works’. In the medical community at large, there is a general acceptance that acupuncture may alleviate pain and that it may serve as an alternative or complement to pharmacological interventions (World Health Organization, 2003
).
When dealing with acupuncture and research, it is obvious that already when the patient has accepted the study criteria, she is part of a selected group, as she is willing to accept acupuncture for pain relief. However, these are the conditions for all randomized trials, as Dr Renckens is aware. Of course one could never disregard a possible influence of nurses and physicians, even if care is taken to treat study groups equally, as was the case in the present study (Humaidan and Stener-Victorin, 2004). However, again this issue is not peculiar to an RCT on acupuncture. The motivation and ability of the patient to cope with pain during oocyte retrieval, and also the support from the medical team, is an important component of pain relief, regardless of the method used. Interestingly, recent functional neuroimaging studies indicate that expectations, both certain and uncertain, play an important role in modulation of both acute and chronic pain, and that expectation is mediated by neural pathways (Ploghaus et al., 2003). Furthermore, it is a well known fact that the effect of all types of pain relief may be lost if the patient feels emotionally unsafe and uncomfortable with the method used.
Dr Renckens argues that conventional methods of pain relief during oocyte retrieval are still to be preferred. This of course presumably is based on his own experience, limited to conventional methods only.
First of all, Dr Renckens has missed our recent study showing that electro-acupuncture (EA) as analgesia during oocyte retrieval induces as good analgesia as alfentanil (Stener-Victorin et al., 2003). Thus, EA—when used in combination with a paracervical block (PCB)—has in two previous trials been found to be as effective as alfentanil in inducing adequate analgesia during oocyte retrieval (Stener-Victorin et al., 1999, 2003). In the study by Humaidan and Stener-Victorin under discussion, the EA group had a significantly higher pain scoring during oocyte retrieval compared with the conventional medical analgesia (CMA) group. On the basis of the previous studies, we suggested that the difference in pain ratings most probably relied on the fact that the CMA group, unlike the EA group, was pre-medicated, since the level of pain in the EA group of Humaidan and Stener-Victorin was comparable with the levels of the EA groups in the two previous studies (Stener-Victorin et al., 1999, 2003; Humaidan and Stener-Victorin, 2004).
Interestingly enough, 1–2 h after oocyte retrieval, when all three studies were grouped and analysed together using the meta-view program in Review Manager 4.1 (The Cochrane Collaboration), the post-operative abdominal pain was significantly lower in the EA groups as compared with the alfentanil and CMA groups independently of pre-medication.
It therefore seems strange, and above all unscientific, when Dr Renckens argues that the methods of choice for oocyte retrieval are conventional methods—without referring to any RCT studies. A review regarding conscious sedation for IVF showed that no method whatsoever could be regarded to be superior to the other and consensus was not obtained as to which method was the best for pain relief during oocyte retrieval (Trout et al., 1998).
In the present study, 91% of patients treated with EA during oocyte retrieval did not require any alfentanil, thus proving the pain-relieving effect of EA. We acknowledge that the EA group for a short period of time had a higher pain score than the CMA group, but again the CMA group was pre-medicated. Furthermore, the effects of alfentanil on oocyte quality and implantation currently are unknown, but alfentanil has been found in follicular fluid shortly after i.v. injection (Soussis et al., 1995). In contrast, there are no side effects reported by EA in the present study.
Last, but not least, the effect of acupuncture relies on a physiological basis which has been described in detail in our previous debate article (Stener-Victorin et al., 2002). Counter-irritation is a part of the endogenous pain-controlling system which is activated during EA analgesia (Stener-Victorin et al., 2002). Different acupuncture protocols, for instance the acupuncture points used, but also the type of electrical stimulation, may result in different analgesic effects. In a recent review, it was suggested that different endogenous opioid systems will be activated depending on the electrical frequency used for stimulation (Han, 2004). The best stimulation frequency and the optimal acupuncture points for analgesia during oocyte retrieval still remain to be elucidated in future RCTs.
As we have stated before: lack of clear evidence of an effect is not equal to evidence of lack of an effect. An increasing body of scientific evidence has already proven the endogenous changes at the level of stress hormones, opiates and gonadotrophins induced by acupuncture.
During a time when there is an increasing consensus that stimulation protocols should be tailored for the individual patient, we are convinced that even the method of sedation should be individualized, knowing the variability in pain from patient to patient. Finally, the patients, and we ourselves, still consider EA to be a good analgesic alternative for oocyte retrieval.
References
Han JS (2004) Acupuncture and endorphins. Neurosci Lett 361, 258–261.[CrossRef][ISI][Medline]
Humaidan P and Stener-Victorin E (2004) Pain relief during oocyte retrieval with a new short duration electro-acupuncture technique—an alternative to conventional analgesic methods. Hum Reprod 19, 1367–1372.
Ploghaus A, Becerra L, Borras C and Borsook D (2003) Neural circuitry underlying pain modulation: expectation, hypnosis, placebo. Trends Cogn Sci 7, 197–200.[CrossRef][ISI][Medline]
Soussis I, Boyd O, Paraschos T, Duffy S, Bower S, Troughton P, Lowe J et al. (1995) Follicular fluid levels of midazolam, fentanyl, and alfentanil during transvaginal oocyte retrieval. Fertil Steril 64, 1003–1007.[ISI][Medline]
Stener-Victorin E, Waldenstrom U, Nilsson L, Wikland M and Janson PO (1999) A prospective randomized study of electro-acupuncture versus alfentanil as anaesthesia during oocyte aspiration in in-vitro fertilization. Hum Reprod 14, 2480–2484.
Stener-Victorin E, Wikland M, Waldenstrom U and Lundeberg T (2002) Alternative treatments in reproductive medicine: much ado about nothing: acupuncture—a method of treatment in reproductive medicine: lack of evidence of an effect does not equal evidence of the lack of an effect. Hum Reprod 17, 1942–1946.
Stener-Victorin E, Waldenstrom U, Wikland M, Nilsson L, Hagglund L and Lundeberg T (2003) Electro-acupuncture as a peroperative analgesic method and its effects on implantation rate and neuropeptide Y concentrations in follicular fluid. Hum Reprod 18, 1454–1460.
Trout SW, Hazard Vallerand AH and Kemmann E (1998) Conscious sedation for in vitro fertilization. Fertil Steril 69, 799–808.[CrossRef][ISI][Medline]
World Health Organization (2003) Acupuncture: review and analysis of reports on controlled clinical trials. www.who.int/medicines/library/trm/acupuncture/acupuncture_trials.doc.
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