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Effects of Epidural Analgesia: Some Questions and Answers JamesA. Thorp, M.D., JayD. McNitt, M.D., and Phyllis C. Leppert, M.D., Ph.D., C.N.M. ABSTRACT: The effects of epidural analgesia on first labors have been studied by Thorp and colleagues (1,2). One study has been published (3) and is the subject of a question-and-answer discussion, presented here. In this study 711 consecutive nulliparous women at term, with spontaneous onset of labor and cephalic presentation, were divided into one group ( n = 447) who received epidural analgesia in labor and another group (n = 264) who received narcotics or no analgesia. The frequency of cesarean section for dystocia was significantly greater (p < 0.005) in the epidural group (10.3%) than in the nonepidural group (3.8%), even after selection bias was corrected and the variables of maternal age and race; gestational age; cervical dilatation on admission; use, duration, and maximum infusion rate of oxytocin; labor duration; presence of meconium; and birth weight were controlled. For both groups the frequency of cesarean section for fetal distress was similar (p < 0.20), and the frequency of low Apgar scores at 5 minutes and cord blood gas values showed no significant differences. The authors concluded that “epidural analgesia in labor may increase the incidence of cesarean section for dystocia in nulliparous women” (3). (BIRTH 17:3, September 1990)

Dr. Thorp Question: What has been the response of the medical community and your peers to your research on the effects of epidural analgesia in first labors? Thorp: Both of our studies were formally presented at two major national meetings (1,2). The first one has been published (3), and the second has been accepted for publication (4). Response from the vast majority of obstetricians at both meetings was that these studies confirmed their observations from clinical practice. Most anesthesiologists responded

James A . Thorp is Associate Director, Maternal-Fetal Medicine, St. Luke’s Hospital, Kansas City, MO. Jay D . McNitt is Clinical Associate Professor, University of Missouri and Department of Anesthesia, St. Luke’s Hospital, Kansas City, MO. Phyllis C . Leppert is Chief and Associate Professor, Department of Obstetrics and Gynecology, Rochester General Hospital, Rochester, N Y. Address correspondence to James Thorp, M . D . , Perinatal Consultants, The Outpatient Center, 4400 Wornall R d . , Kansas City, M O 641 11.

in a skeptical and critical manner, and a few were outraged at the publicity that these studies received because it may cause patients to be reluctant to use an epidural in labor for fear of cesarean birth. Question: In view of the increase in primary cesarean sections over the past 15 years, and the growing popularity of epidurals and their potential contribution to the cesarean section rate, why do you think there has been so little research on the use and safety of epidural analgesia in labor, and what important areas should be investigated? Thorp: Like many other areas in medicine, this is yet another example of technology being implemented and widely accepted before it has been adequately studied in clinical trials. Similar to intrapartum fetal heart rate monitoring (4), epidural analgesia in labor gained widespread use and we-physicians, nurses, and patients-believed in it and grew to depend on it. After it became generally accepted (as with intrapartum monitoring), some concerns surfaced, and now it has become extremely difficult to turn around and perform a randomized, controlled trial. Since such a trial would entail assigning patients to a nonepidural

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group, many physicians and nurses believe that it is unethical. It is quite alarming to see how nurses and physicians rely on epidural analgesia in labor. Many nurses who practice in institutions where it is the preferred analgesia have lost their clinical ability to coach and assist a patient through labor without an epidural, and become noticeably uncomfortable when asked to do so. It is much easier for a nurse to call anesthesia and see the patient smiling during labor than it is for her to stay at the woman’s bedside and help her through an uncomfortable labor. At many institutions the rule rather than the exception is a call from the nurse in early labor asking, “Doctor, when can I call anesthesia for Mrs. Smith’s epidural?” Clearly, the question of whether or not an epidural increases the frequency of instrumental vaginal delivery or cesarean section has not been addressed adequately in a randomized, controlled trial in the United States. It may be that its effects on instrumental delivery and cesarean section rates are minimized in institutions where staff are acutely aware of the potential of epidural to interfere with labor. In institutions where there is a lack of experience or concern, however, epidural analgesia may have a profound effect on the frequency of instrumental delivery and cesarean section. To address this question the ideal study must randomize nulliparous patients in early labor to an epidural or a nonepidural group. In view of the recent studies ( 1 -3) demonstrating a significant association between epidural analgesia and cesarean section for dystocia in these women, such a definitive study must be done. Such a study was, in fact, reported from Europe last year, and it is of great interest that this study, even though it included multiparous patients, demonstrated a threefold increase in frequency of cesarean section for dystocia in the epidural group ( 5 ) . Question: Why do you think epidural analgesia reduces the likelihood of a woman having a normal labor and delivery, especially for her first birth? Thorp: There are many mechanisms by which epidural analgesia could increase the frequency of cesarean section for dystocia. All of the following potential mechanisms have a basis in the literature: 1. Decreased uterine activity (6- 10) 2. Prolongation of the first stage of labor (1 1 - 14) 3. Relaxation of the pelvic diaphragm predisposing to minor malpresentation (15,16) 4. Decreased maternal urge to push (17,18) 5. Decreased maternal ability to push (7,17) 6. Prolonged second stage of labor (7,11,12,14,17) 7. Increased risk of instrumental vaginal delivery,

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a procedure that is unlikely to be performed for medicolegal reasons (1 5,18) Since dystocia is relatively rare in multiparous labors compared with first labors, it is highly likely that one of these mechanisms would be clinically relevant in a first labor. Our investigations (1-3) were not designed to ascertain the exact mechanisms leading to cesareans. However, any one or a combination of the mechanisms listed could account for the increased frequency of these deliveries associated with epidural in our study. Question: What are your guiding principles in managing the dilemma of the patient’s right to choose versus the physician’s concerns for reducing the number of cesareans if, for example, a woman (nullipara) with 3 cm dilatation and slow labor progress demands to be given an epidural? Thorp: The patient who demands medical therapy that is not in her best interest, or is not indicated, represents a dilemma. This is often seen in obstetrics, not only with epidural analgesia, but perhaps more frequently with elective cesarean section. Such patients are threatening to caregivers because of their medicolegal potential. “Loss of consortium from painful labor” caused by a poorly functioning epidural analgesia was a plaintiff’s basis for a $500,000 lawsuit in at least one case. Once a patient demands a certain medical therapy, both parties are in a no-win situation, since there is complete breakdown of the physician-patient relationship. Perhaps this is best avoided by careful prenatal education. It is easier to explain analgesic preferences to a patient before rather than during a painful labor. In the situation described in the question, I would explain my preference to the patient and family, and attempt to delay the epidural by encouragement, ambulation, and narcotics, if necessary. Question: What is the anticipated outcome for a full-term nullipara, with cephalic presentation and slow labor progress, if an epidural is administered at a cervical dilatation of 5 cm or less, compared with a woman who has identical characteristics except that she does not receive an epidural? Thorp: In our study (2) we found that the frequency of cesarean section for dystocia was 20.6 percent in the group having slow labor progress and epidural at less than 5 cm dilatation compared with 3.4 percent in those having slow labor progress and no epidural (p < 0.00006). It should be emphasized that this study was retrospective, and therefore one cannot be certain that both groups had otherwise identical characteristics.

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Question: Oxytocin augmentation according to the principles of active labor management was used in over one-half of the 711 nulliparous women whom you studied, yet you describe this management as being only “partially successful,” since it did not reduce the cesarean section rate to the 5 percent range of National Maternity Hospital in Dublin (19).What factors do you believe contributed to this partial success, and to what extent was failed induction a factor? Thorp: Some have explained the partial success to the racial heterogeneity of the Houston population versus the homogeneity of the Dublin population. That is an inadequate explanation in my opinion, because at least one other center serving a multiracial population approached the 5 percent cesarean section rates reported from Dublin. Others have suggested that the true form of active management of labor (AML), as it is practiced at the National Maternity Hospital (19), was not practiced in Houston. This is particularly true for the organizational component of AML, and not the medical component, which is often overemphasized and more easily implemented. In Dublin, one Master is responsible for establishing protocol for labor management of all patients. In comparison, in Houston, where AML was first implemented in the United States, more than 50 physicians were responsible for the care of patients. This is certainly part of the explanation. Another consideration is the extensive use of epidural analgesia in Houston compared with that in Dublin. Failed induction was not an explanation in our studies (1,3)because we included only patients who entered labor spontaneously. Thus every woman who received oxytocin was augmented and not induced. This does raise an important and common misconception regarding AML; that is, AML does not involve induction of labor. Dr. McNitt

Question: Please comment on the significance of the finding by Thorp et a1 that continuous epidural analgesia increases the frequency of cesarean section for dystocia in nulliparous women. McNitt: The recently published study by Thorp et a1 (3)is of the utmost concern to all physicians involved in the care of obstetric patients. The increased cesarean delivery rate over the last few years has increased maternal morbidity and mortality (20),as well as raised the economic costs associated with parturition. Thorp’s group concluded that epidural analgesia for labor may increase the frequency of cesarean delivery performed for dystocia in nulliparous women. If this is indeed the

159 case, maternal morbidity and mortality and economic costs may be favorably altered by eliminating or restricting epidural analgesia for labor in these women. Several facets of this study deserve in-depth analysis before such conclusions are accepted. Because the study was retrospective, one cannot guarantee that all patients received equivalent obstetric management. Neuhoff et a1 (21)demonstrated a difference in cesarean delivery rate when comparing a clinic and a private obstetric service. Although both groups had a similar percentage of patients who received epidural analgesia for labor (41.6% clinic, 41.7% private), the clinic population had a significantly lower cesarean delivery rate for failure to progress (1.2% clinic, 20.2% private; p < 0.0001).The authors concluded that “only specific management alternatives elected by the physicians involved could be responsible for the differences in mode of delivery” (21). One cannot be assured that such management differences were not present in the study by Thorp et al because of its retrospective nature. The authors did not control for maternal height. Scott and Strickland (22) noted a 4.9-fold increase in cesarean delivery performed for dystocia in nulliparous women who were less than 63 inches tall. If more women in Thorp’s epidural group were under 63 inches, that may explain the increased cesarean section rate seen in that group. The presence of preexisting abnormalities of labor cannot be excluded. The authors deleted from their analysis six patients who had cervical dilatation rates less than 1 cm per hour before epidural analgesia. Because dilatation rates before and after epidural analgesia are not given, one could conclude that the group who received an epidural may have had abnormal labor before it was given. This may also explain the higher use of oxytocin in the epidural group; that is, more patients had abnormal labor before an epidural was given. Jouppila et al (13) demonstrated a normalization of the first stage of labor in patients who were already receiving oxytocin after the establishment of epidural analgesia. In their study the number of patients who required oxytocin after epidural analgesia was not different from the control group (4% epidural, 3% control). Neuhoff et al (21)showed a cesarean delivery rate near 25 percent (50 of 199) for private nulliparous patients receiving oxytocin. The remaining 216 women who did not require oxytocin and were supposedly managed in the same manner had a cesarean rate of 3.2 percent. Epidural analgesia did not alter the cesarean delivery rate in private nulliparous patients receiving oxytocin (25.4% epidural, 24.7% control) (21). Because Thorp et al

160 do not provide details about when oxytocin was used and when epidural analgesia was used, one cannot be certain that the epidural group did not have preexisting abnormalities of labor that led to cesarean delivery independent of the epidural. In addition, the painful contractions associated with the use of oxytocin may have been the reason that women requested additional analgesia (epidural). Perhaps all that these data mean is that patients with abnormal labor are most likely to receive oxytocin, most likely to need an epidural for analgesia, and eventually proceed to the cesarean section they were destined to undergo. Thorp et al did not provide specific information regarding the indication for cesarean delivery. At some institutions arrest of the first stage of labor is treated with epidural analgesia in an attempt to “relax” the parturient. An epidural may also be instituted due to strong suspicion that the patient may need a cesarean delivery. If a patient has arrest of dilatation and an epidural is given but she is still unable to progress, she would be included in the study’s epidural group, when obviously arrest of labor occurred before the epidural was administered. Such factors cannot be excluded based on the data presented. The diagnosis of cephalopelvic disproportion (CPD) was included as a reason for cesarean section for dystocia in this study. Epidural analgesia most definitely does not cause CPD but may be used more frequently in such patients, since they undoubtedly have more painful and prolonged labor. Because the authors did not give a specific breakdown regarding indications for cesarean section, CPD cannot be excluded as a bias in the study. The number of cesarean deliveries performed in the second stage of labor was also not identified. Epidural analgesia probably does increase the duration of second stage, at least statistically (23). If an arbitrary time limit is placed on the duration of the second stage, more cesarean sections could result from such a prolongation. Despite these limitations inherent in a retrospective, nonrandomized study, I think the paper by Thorp et a1 is a valuable addition to our knowledge. The issue raised by the authors should encourage a prospective, randomized trial of epidural analgesia for labor that will show whether its association with cesarean delivery is cause and effect or merely coincidental. Question: Epidural analgesia has been described by some physicians as the “Cadillac” of obstetric pain control. Is this status justified, and how safe is an epidural for mother and newborn?

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McNitt: Crawford recently published a review of 26,490 lumbar epidural analgesics administered for labor over 17 years (24). The author grouped the complications encountered by their severity. Potentially life-threatening complications occurred in nine patients and were related to intrathecal and intravenous catheter placement. Intravenous administration of bupivacaine, 50 to 60 mg, resulted in seizures in three women (0.01%). All three were appropriately treated and neither they nor the neonates suffered permanent sequelae. Six women received intrathecal local anesthetic (0.02%), one of whom developed hypotension and cardiac arrest with subsequent fetal distress and required cesarean delivery. Two of these patients developed postdural puncture headache, which in one persisted for five months. All mothers and infants did well otherwise. Prompt recognition and treatment of these nine complications undoubtedly prevented more serious morbidity or even mortality, and testify to the need for an immediately available individual who is trained in managing these rare but serious complications. Serious but not life-threatening complications of epidural analgesia were also infrequent. Injection of a spicule into the epidural space resulting in foot drop was described. This patient required a laminectomy but made a complete recovery. Another complication was an infected epidural hematoma in a bacteremic woman with delayed development of an epidural abscess that required a laminectomy. Unfortunately, she developed subacute bacterial endocarditis. Complications regarded as moderate to serious were more frequent. Two cases of persistent hypotension were reported; however, there were no untoward maternal or neonatal effects. In two cases of bizarre analgesic patterns the epidural was abandoned and no persistent problems occurred in these patients. Backache localized to the epidural cannulation site that persisted for more than three days after delivery occurred in 1 of every 2000 patients. Other miscellaneous complications were described, none of which caused significant morbidity. Mildly disturbing complications consisted of a unilateral sixth cranial nerve palsy, shearing off of catheters in the epidural space, and sacroiliac strain due to a leg slipping off a bed. Again, no permanent deficits were noted. The authors described several other unusual complications, and interested readers are referred to the article (24). Crawford did not address the frequency of postdural puncture headache specifically. Reports from teaching institutions cite an occurrence of 0.5 to 2.0 percent (25). Of these patients, 50 to 80 percent will

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require an epidural blood patch for treatment of headache. In summary, the frequency of complications after epidural analgesia for labor appears to be low. Strict attention to placement procedures and dosing of catheters cannot be overemphasized. The presence of properly trained individuals to recognize and treat associated complications should continue to make this a safe technique. Question: What information do you recommend be disclosed to a pregnant woman before administration of epidural analgesia, to comply with the principles and practice of informed consent and her right to be an active participant in decisions about her care? McNitt: I think the best time to discuss risks and benefits of epidural analgesia for labor is before labor. At our institution most of this information is provided by obstetric nurses during prepared childbirth classes. In addition, before placement of an epidural, the potential for headache, back pain, blood pressure changes, and inadequate analgesia are explained to the woman by the anesthesiologist. I do not routinely discuss effects of epidural analgesia on progress of labor or mode of delivery because I think these questions have not been adequately answered in a scientific manner. If a patient requests such information, I explain the various theories to her. Dr. Leppert

Question: What approaches have you found work best to help a laboring woman avoid the use of medications and augmentation when progress is slow and she is having trouble coping with pain? Leppert: The ability to cope with pain in labor demands many things of the woman herself and demands the utmost in personal, obstetric, and nursing skills. It is understandable that in today’s busy hospitals a laboring woman may not have the opportunity or the ability to cope, since she does not always have an individual caregiver whose only responsibility is to her alone. This is fundamental. The most important requirement is a caring person to communicate a deep sense of empathy, a sense of truly being with the laboring woman. All women are sensitive to this caring attitude; it literally fills the room; it is palpable. It means touching her, holding her, and letting her and the baby’s father know each moment is important, and that the work of labor is significant and meaningful. Then every woman will find reward in the joy of birth. I have found over the years that this carefully

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cultivated attitude by a caregiver infuses confidence into the laboring woman. She then can find the ability to trust her body-trust the physiologic process of labor and birth. This is so fundamental to outcome and is so much more important than the actual physical environment. What I am suggesting is that every room is a “birth” room regardless of the woman’s risk status, and it is the attitude of the caregivers that makes it so. The attitude that creates this atmosphere of trust is consciously developed by every birth attendant, from nurse to obstetrician. Acquiring such a skill is difficult work, but it is necessary in order for the caregiver to be truly “with woman.” No woman should be left alone in labor. Only in the presence of a caring, skilled human being will she relax completely, thus enhancing the process of birth. This is the first approach. Skill and knowledge follow. A thorough understanding of the physiology and anatomy of parturition leads to the knowledge that women labor best and most effectively, and often with less pain, in an upright position, not a supine one. If a woman’s labor progresses too slowly, having her ambulate is most important. It has been understood scientifically for many years that uterine contractions are stronger and more frequent when a woman stands. She should be allowed to walk as much as possible. She can stand and hold another person when her contractions begin. Slow, relaxed breathing in early labor and shallow breathing in later labor are helpful coping mechanisms. A cool washcloth on her forehead, a back rub, and pressure against the back during a contraction are also helpful. Quiet reassurance and explanations between contractions are vital in aiding a woman to cope. For an occipitoposterior presentation, pushing while standing, sitting, or in lateral Sims’ position helps labor progress, too. Pelvic rocking, knee-chest position, and sitting in a rocking chair are excellent approaches. All laboring women should be given permission to be themselves, and this includes the need to express negative feelings or to cry out with pain. A warm shower at the appropriate time can also augment labor. I am impressed with the fact that the group of women who did not receive epidurals in the study by Thorp et a1 (3) had progressed to 4.8 cm dilatation on average, as opposed to 3 cm in the epidural group. It might be that the women were different in their ability to cope with labor, a variable not addressed by the study. One aspect of the difference between Dublin (19) and Houston (3) is that in Dublin, midwives are much involved in the care of

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laboring women, whereas in Houston apparently they are not. There is a time and place for the appropriate use of epidural anesthesia. Sometimes, however, when a woman demands an epidural she may really be telling her caregivers that she is having trouble coping with labor. What she needs is encouragement, position changes, touching, and a caring attitude from her caregiver. As professionals, we must recognize that we might often give epidural anesthesia j u s t because that makes it easier to “manage.” True midwifery-being “with woman” -is hard work. It is this hard work, however, that makes nurses, doctors, and nurse-midwives the professionals that we are. Question: For a busy unit where there is no time or staff for that approach, what do you think would be the next best way to help a woman avoid medication? L e p p e r t : Having a doula, a trained labor companion, who would assume the responsibility for the approaches I have described. Many years ago I had the privilege of accompanying the late Dr. Kloosterman, from The Netherlands, on a visit to a large urban teaching hospital. One lonely, frightened woman was having a terrible time coping with labor. Dr. Kloosterman instinctively broke away from his United States visitor and went to her side. Her sudden calmness and comfort were apparent to all. “No woman,” he stated, quoting another obstetrician, “should ever be alone in labor.” References Thorp JA, Parisi VM, Boylan PC, Johnston D. The effect of epidural analgesia on cesarean section for dystocia in primigravidae. Presented at the 9th annual meeting of the Society of Perinatal Obstetricians, New Orleans, LA, February 1989. Thorp JA, Eckert L, Ang M, Johnston D, Peaceman A, Parisi VM. Epidural analgesia and cesarean section for dystocia: Risk factors in nulliparas. Presented at the national ACOG meeting, Atlanta, GA, May 1989, and accepted for publication in The American Journal of Perinatology. Thorp JA, Parisi VM, Boylan PC, Johnston DJ. The effect of continuous epidural analgesia on cesarean section for dystocia in nulliparous women. Am J Obsret Gynecol 1989;161:670-675. Freeman R. Intrapartum fetal monitoring-A disappointing story. N Engl J Med 1990;322:624-626.

5 . Philipsen T, Jensen NH. Epidural block or parenteral pethidine as analgesic in labour; a randomized study concerning progress in labour and instrumental deliveries. Eur J Obstet Gynecol Reprod Biol 1989;30:27-33. 6. Crawford JS. Principles and Practice of Obstetric Anaesthesia, 5th ed. Boston: Blackwell, 1984:242-243. 7 . Bromage PR. Epidural Analgesia. Philadelphia: WB Saunders, 1978526. 8. Goodfellow CF, Hull MGR, Swaab DF, Dogterom J, Buijs RM. Oxytocin deficiency at delivery with epidural analgesia. Br J Obstet Gynaecol 1983;90:214-219. 9. Lowensohn RI, Paul RH, Fales S, Yeh SY, Hon EH. Intrapartum epidural anesthesia: An evaluation of effects on uterine activity. Obstet Gynecol 3974;44:388-393. 10. Bates RG, Helm CW, Duncan A, Edmonds DK. Uterine activity in the second stage of labour and the effect of epidural analgesia. Br J Obstet Gynaecol 1985;92:1246-1250. 11. Diro M, Beydoun SN. Segmental epidural analgesia in labor: A matched control study. J Nut1 Mud Assoc 1985; 78:569-573. 12. Studd JWW, Crawford JS, Duignan NM, Rowbotham CJF, Hughes AO. The effect of lumbar epidural analgesia on the rate of cervical dilatation and the outcome of labour of spontaneous onset. Br J Obstet Gynaecol l980;87: 10151021. 13. Jouppila R, Jouppila P, Karinen JM, Hollmen A. Segmental epidural analgesia in labour: Related to the progress of labour, fetal malposition and instrumental delivery. Actn Obstet Gynecol Scand 1979;58:135-139. 14. Poore M, Foster JC. Epidural and no epidural anesthesia: Differences between mothers and their experience of birth. Birth 1985;12:205-212. 15. Hoult IJ, MacLennan AH, Carrie LES. Lumbar epidural analgesia in labour: Relation to fetal malposition and instrumental delivery. Br Med J 1977;l:14-16. 16. Raabe N, Belfrage P. Lumbar epidural analgesia in labour. Acta Obstet Gynecol Scand 1976;55:125-131. 17. Morgan B. Problems in Obstetric Anesthesia. New York: John Wiley & Sons, 1987:llO. 18. Kaminski HM, Stafl A, Aiman J. The effect of epidural analgesia on the frequency of instrumental obstetric delivery. Obstet Gynecol 1987;69:770-773. 19. O’Driscoll K, Foley M, MacDonald D. Active management of labor as an alternative to cesarean section for dystocia. Obstet Gynecol 1984;63:485-490. 20. Danforth D. Cesarean section. JAMA 1985;253:811-818. 21. Neuhoff D, Burke S, Porreco R. Cesarean birth for failed progress in labor. Obstet Gynecol 1989;73:915-920. 22. Scott R, Strickland D. Maternal height and weight gain during pregnancy as risk factors for cesarean section. Milit Med 1989;154:365-367. 23. Chestnut D, Vandewalker G, Owen C, Bates J , Choi W. The influence of continuous epidural bupivacaine analgesia on the second stage of labor and method of delivery in nulliparous women. Anesthesiology 1987;66:774-780. 24. Crawford JS. Some maternal complications of epidural analgesia for labor. Anaesthesia 1985;40:1219- 1225. 25. Hood D. Obstetric anesthesia complications. In: Hood D, ed. Problems in Anesthesia. Philadelphia: JB Lippincott, 1989;3:1-17.

Effects of epidural analgesia: some questions and answers.

The effects of epidural analgesia on first labors have been studied by Thorp and colleagues. One study has been published and is the subject of a ques...
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