BJOG Exchange
normal saline continuous intraperitoneal infusions following laparoscopic hysterectomy.1 Laparoscopic hysterectomy is meant to be a day case and this form of analgesia for 48 hours may delay patient ambulation and discharge. The routine use of patient-controlled anaesthesia (PCA) does not encourage the day case approach, at a time when vaginal hysterectomy is being seen as a day case procedure.2 The fluid may cause pain by irritation to the peritoneum, make it difficult to diagnose intraperitoneal bleeding and lead to leakage of fluid through the vaginal vault. The use of a drain in the presence of such irrigation is interesting. Gastric banding is not the best comparison, as the extent of peritoneal trauma is different, especially in patients who require subsequent laparotomy. The management of continuous infusion analgesia should have been specified in those patients who went back to theatre. The trial should have included an arm without such technique, either as a third arm or instead of the saline arm. Such a comparison would have enabled a judgment as to whether the use of this approach makes less (or more) pain and, if so, whether this effect is caused by the use of local anaesthetic or any fluid (placebo effect). Likewise, grouping all three types of laparoscopic hysterectomy reduces the sample size (power) for comparing both arms for each type of laparoscopic hysterectomy. This is particularly pertinent, as the results did not provide the numbers of each type in each arm, let alone compare the two arms in this respect. The normality of continuous numerical data was not confirmed before the selection of statistical tests for their description and comparison. The mean standard deviation and the median [interquartile range], rather than the range, are the standard presentation format. The nature of the figures in relation to parity should have been stated. The statistical tests used for each comparison should have been specified,
1442
together with the P value. A valid statistical comparison is still possible even with low frequencies. Complications should have been specified, as some may cause pain and therefore increase the analgesic requirements. A composite outcome measure for total anaesthetic and analgesic use, complications and different types of endometriosis would have been more informative. Each table column should have a heading. It would have been better to use hours after surgery, rather than time of the day, when comparing post-operative pain scores. Likewise, it would have been better to provide data about post-operative stay in hospital in table format, with statistical comparison. The lack of any information about infiltration around the cervix is noted. The discussion of post-operative pain relief and its implications to patient comfort, recovery and cost deserves more attention and consideration, in terms of both pathology and pharmacology, as well as clinical studies, which would have provided far more references than relied upon in this study. All these points should be borne in mind in any future research into this area. & References 1 Andrews V, Wright JT, Zakaria F, Banerjee S, Ballard K. Continuous infusion of local anaesthetic following laparoscopic hysterectomy: a randomised controlled trial. BJOG 2014;121: 754–60. 2 Chia KV, Tandon S, Moukarram H. Vaginal hysterectomy is made easier with ERBE Biclamp forceps. J Obstet Gynaecol 2007;27:723–5.
S Ismail Department of Obstetrics and Gynaecology, Royal Sussex County Hospital, Brighton, East Sussex, UK Accepted 27 May 2014. DOI: 10.1111/1471-0528.12974
Authors’ reply Sir, We would like to thank Dr Ismail for his letter and comments in response to our recent publication.
The continuous infusion of local anaesthetic was via an elastomeric pump. This can be placed in one’s pocket or clipped to clothing with the provided clip and, in itself, does not delay discharge or ambulation. Indeed, such pumps have been shown to both increase ambulation and decrease hospital stay.1–3 Similarly, the use of patient-controlled anaesthesia (PCA) following laparoscopic surgery has been shown to enhance mobility and decrease hospital length of stay.4 From a study design perspective, we opted to use PCA as it provided an objective measure of the quantity of analgesic used. We considered having a third arm in which participants were not provided with any infusion, but felt that it was more important to ensure the blinding of both the participants and the surgeons and that this would not have been possible with a ‘no infusion’ arm. We accept that the use of a peritoneal infusion may cause irritation and, in our discussion, we consider the idea that bupivacaine may in fact increase irritation. The normality of continuous data was confirmed, and parametric and non-parametric test were used appropriately. Hence, we used both medians and means, together with the appropriate statistical tests. The tables clearly demonstrate that normally distributed continuous variables are represented by the mean and standard deviation, and descriptions of non-parametric data are shown as medians with an interquartile range. In each of the analyses, the test used is stated in the table and P values are provided where appropriate. Each column in the tables has a heading. We accept that it would have been better to give the hours from surgery rather than the time of day, although the accurate measures of this can be difficult to achieve. We reported the statistical significance of group differences in hospital stay. All women had xylocaine with 1 in 100 000 infiltrated around the cervix and this should have been mentioned in the text.
ª 2014 Royal College of Obstetricians and Gynaecologists
BJOG Exchange
This was a double-blind study that objectively measured the impact of continuous local anaesthetic infusion and found no advantage with the treatment. As with any trial, it is important to ensure that the study design is robust and that the results are reliable. We hope that we have addressed the concerns raised by Dr Ismail. & References 1 Iyer CP, Robertson BD, Lenkovsky F, Huerta S, Livingston E, Thurmon JJ. Gastric bypass and On-Q pump: effectiveness of Soaker Catheter system on recovery of bariatric surgery patients. Surg Obes Relat Dis 2010;6:181–4. 2 Yoost TR, McIntyre M, Savage SJ. Continuous infusion of local anesthetic decreases narcotic use and length of hospitalization after laparoscopic renal surgery. J Endourol 2009;23:623–6. 3 Levy BF, Scott MJ, Fawcett W, Fry C, Rockall TA. Use of the ON-Q pain management system is associated with decreased postoperative analgesic requirement: double blind randomized placebo pilot study. J Am Coll Surg 2006;202:297–305. 4 Levy BF, Scott MJ, Fawcett W, Fry C, Rockall TA. Randomized clinical trial of epidural, spinal or patient-controlled analgesia for patients undergoing laparoscopic colorectal surgery. Br J Surg 2011;98:1068–78.
V Andrews,a JT Wrightb & K Ballardb a
University Hospital Lewisham, London, UK Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
b
Accepted 3 June 2014. DOI: 10.1111/1471-0528.12975
Noninvasive prenatal testing for trisomy 21: when counselling is needed before responding to a survey
Sir, Lewis et al.1 assess the views and likely take-up of noninvasive prenatal testing (NIPT) for trisomy 21 among potential service users in the UK, with potentially important implications for healthcare service providers. The analysis of ques-
tionnaires submitted to more than 1000 women suggests a positive view of the introduction of NIPT into prenatal care and that its take-up is likely to be high. We think that the survey results could be misleading in clinical practice. We agree with the authors’ analysis of the major drawbacks of the study, such as the lack of validation of the questionnaire, the possible differences between the survey findings and the choices that patients actually make in practice, the uncertainty about the way the testing is offered, and bias regarding the population sample, predominantly comprising white, older and well-educated women, which may demonstrate a higher likely take-up compared with the population as a whole. Nevertheless, the absence of counselling before individuals complete the survey is a pitfall that, in our opinion, has not been sufficiently stressed and that may lead to misleading conclusions. Indeed, informed counselling has played a fundamental role in the introduction of DNA sequencing methods in prenatal care. In December 2012, the American College of Obstetricians and Gynecologists Committee on Genetics stressed the need for careful nondirective counselling for women before undergoing NIPT.2 Many important ethical issues have been raised about NIPT, such as the potential for misuse, the risk of normalising testing as routine without a full understanding of the results, social and commercial pressures, and equality of access.3 Service users should be aware of the clinical significance of the test. Actually, NIPT is a highly accurate, time-consuming and expensive screening tool for women at increased risk of aneuploidy. Patients with a positive result have to be submitted for invasive prenatal diagnosis, such as amniocentesis or chorionic villus sampling.2 Unlike traditional screening, there is a test failure rate (range 1.6–13.0%), so women with failed tests are offered a prenatal inva-
ª 2014 Royal College of Obstetricians and Gynaecologists
sive diagnosis or a second-trimester screening test (the quadruple test), and are treated as positive only if this test is positive.4 Indeed test failure could reduce accuracy, which is reported as over 99% in the survey by Lewis and colleagues,1 and reduce the time available for the expectant parents to make important choices. Moreover, survey respondents should be made aware of costs and the time it takes to receive the results of NIPT, and this ought then to be reflected in findings that are more comparable to the choices that patients actually make in practice. Merging NIPT into the current prenatal screening pathway in the National Health Service seems to be feasible. Wald and colleagues4 proposed a screening model that should minimise false positives at a substantially lower cost than universal DNA testing. In our opinion, observational studies are an interesting way of assessing views about NIPT among potential service users. Nevertheless, counselling should be provided for the survey respondents to obtain more reliable figures about likely uptake and the possibility of merging DNA sequencing methods into the current prenatal screening pathway in the National Health Service. & References 1 Lewis C, Hill M, Silcock C, Daley R, Chitty L. Non-invasive prenatal testing for trisomy 21: a cross-sectional survey of service users’ views and likely uptake. BJOG 2014;121: 582–94. 2 American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 545: noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol 2012;120:1532–4. 3 Hill M, Barrett AN, White H, Chitty LS. Uses of cell free fetal DNA in maternal circulation. Best Pract Res Clin Obstet Gynaecol 2012;26: 639–54. 4 Wald NJ, Bestwick JP. Incorporating DNA sequencing into current prenatal screening practice for Down’s syndrome. PLoS One 2013;8:e58732.
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normal saline continuous intraperitoneal infusions following laparoscopic hysterectomy.1 Laparoscopic hysterectomy is meant to be a day case and this form of analgesia for 48 hours may delay patient ambulation and discharge. The routine use of patient-controlled anaesthesia (PCA) does not encourage the day case approach, at a time when vaginal hysterectomy is being seen as a day case procedure.2 The fluid may cause pain by irritation to the peritoneum, make it difficult to diagnose intraperitoneal bleeding and lead to leakage of fluid through the vaginal vault. The use of a drain in the presence of such irrigation is interesting. Gastric banding is not the best comparison, as the extent of peritoneal trauma is different, especially in patients who require subsequent laparotomy. The management of continuous infusion analgesia should have been specified in those patients who went back to theatre. The trial should have included an arm without such technique, either as a third arm or instead of the saline arm. Such a comparison would have enabled a judgment as to whether the use of this approach makes less (or more) pain and, if so, whether this effect is caused by the use of local anaesthetic or any fluid (placebo effect). Likewise, grouping all three types of laparoscopic hysterectomy reduces the sample size (power) for comparing both arms for each type of laparoscopic hysterectomy. This is particularly pertinent, as the results did not provide the numbers of each type in each arm, let alone compare the two arms in this respect. The normality of continuous numerical data was not confirmed before the selection of statistical tests for their description and comparison. The mean standard deviation and the median [interquartile range], rather than the range, are the standard presentation format. The nature of the figures in relation to parity should have been stated. The statistical tests used for each comparison should have been specified,
1442
together with the P value. A valid statistical comparison is still possible even with low frequencies. Complications should have been specified, as some may cause pain and therefore increase the analgesic requirements. A composite outcome measure for total anaesthetic and analgesic use, complications and different types of endometriosis would have been more informative. Each table column should have a heading. It would have been better to use hours after surgery, rather than time of the day, when comparing post-operative pain scores. Likewise, it would have been better to provide data about post-operative stay in hospital in table format, with statistical comparison. The lack of any information about infiltration around the cervix is noted. The discussion of post-operative pain relief and its implications to patient comfort, recovery and cost deserves more attention and consideration, in terms of both pathology and pharmacology, as well as clinical studies, which would have provided far more references than relied upon in this study. All these points should be borne in mind in any future research into this area. & References 1 Andrews V, Wright JT, Zakaria F, Banerjee S, Ballard K. Continuous infusion of local anaesthetic following laparoscopic hysterectomy: a randomised controlled trial. BJOG 2014;121: 754–60. 2 Chia KV, Tandon S, Moukarram H. Vaginal hysterectomy is made easier with ERBE Biclamp forceps. J Obstet Gynaecol 2007;27:723–5.
S Ismail Department of Obstetrics and Gynaecology, Royal Sussex County Hospital, Brighton, East Sussex, UK Accepted 27 May 2014. DOI: 10.1111/1471-0528.12974
Authors’ reply Sir, We would like to thank Dr Ismail for his letter and comments in response to our recent publication.
The continuous infusion of local anaesthetic was via an elastomeric pump. This can be placed in one’s pocket or clipped to clothing with the provided clip and, in itself, does not delay discharge or ambulation. Indeed, such pumps have been shown to both increase ambulation and decrease hospital stay.1–3 Similarly, the use of patient-controlled anaesthesia (PCA) following laparoscopic surgery has been shown to enhance mobility and decrease hospital length of stay.4 From a study design perspective, we opted to use PCA as it provided an objective measure of the quantity of analgesic used. We considered having a third arm in which participants were not provided with any infusion, but felt that it was more important to ensure the blinding of both the participants and the surgeons and that this would not have been possible with a ‘no infusion’ arm. We accept that the use of a peritoneal infusion may cause irritation and, in our discussion, we consider the idea that bupivacaine may in fact increase irritation. The normality of continuous data was confirmed, and parametric and non-parametric test were used appropriately. Hence, we used both medians and means, together with the appropriate statistical tests. The tables clearly demonstrate that normally distributed continuous variables are represented by the mean and standard deviation, and descriptions of non-parametric data are shown as medians with an interquartile range. In each of the analyses, the test used is stated in the table and P values are provided where appropriate. Each column in the tables has a heading. We accept that it would have been better to give the hours from surgery rather than the time of day, although the accurate measures of this can be difficult to achieve. We reported the statistical significance of group differences in hospital stay. All women had xylocaine with 1 in 100 000 infiltrated around the cervix and this should have been mentioned in the text.
ª 2014 Royal College of Obstetricians and Gynaecologists
BJOG Exchange
This was a double-blind study that objectively measured the impact of continuous local anaesthetic infusion and found no advantage with the treatment. As with any trial, it is important to ensure that the study design is robust and that the results are reliable. We hope that we have addressed the concerns raised by Dr Ismail. & References 1 Iyer CP, Robertson BD, Lenkovsky F, Huerta S, Livingston E, Thurmon JJ. Gastric bypass and On-Q pump: effectiveness of Soaker Catheter system on recovery of bariatric surgery patients. Surg Obes Relat Dis 2010;6:181–4. 2 Yoost TR, McIntyre M, Savage SJ. Continuous infusion of local anesthetic decreases narcotic use and length of hospitalization after laparoscopic renal surgery. J Endourol 2009;23:623–6. 3 Levy BF, Scott MJ, Fawcett W, Fry C, Rockall TA. Use of the ON-Q pain management system is associated with decreased postoperative analgesic requirement: double blind randomized placebo pilot study. J Am Coll Surg 2006;202:297–305. 4 Levy BF, Scott MJ, Fawcett W, Fry C, Rockall TA. Randomized clinical trial of epidural, spinal or patient-controlled analgesia for patients undergoing laparoscopic colorectal surgery. Br J Surg 2011;98:1068–78.
V Andrews,a JT Wrightb & K Ballardb a
University Hospital Lewisham, London, UK Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
b
Accepted 3 June 2014. DOI: 10.1111/1471-0528.12975
Noninvasive prenatal testing for trisomy 21: when counselling is needed before responding to a survey
Sir, Lewis et al.1 assess the views and likely take-up of noninvasive prenatal testing (NIPT) for trisomy 21 among potential service users in the UK, with potentially important implications for healthcare service providers. The analysis of ques-
tionnaires submitted to more than 1000 women suggests a positive view of the introduction of NIPT into prenatal care and that its take-up is likely to be high. We think that the survey results could be misleading in clinical practice. We agree with the authors’ analysis of the major drawbacks of the study, such as the lack of validation of the questionnaire, the possible differences between the survey findings and the choices that patients actually make in practice, the uncertainty about the way the testing is offered, and bias regarding the population sample, predominantly comprising white, older and well-educated women, which may demonstrate a higher likely take-up compared with the population as a whole. Nevertheless, the absence of counselling before individuals complete the survey is a pitfall that, in our opinion, has not been sufficiently stressed and that may lead to misleading conclusions. Indeed, informed counselling has played a fundamental role in the introduction of DNA sequencing methods in prenatal care. In December 2012, the American College of Obstetricians and Gynecologists Committee on Genetics stressed the need for careful nondirective counselling for women before undergoing NIPT.2 Many important ethical issues have been raised about NIPT, such as the potential for misuse, the risk of normalising testing as routine without a full understanding of the results, social and commercial pressures, and equality of access.3 Service users should be aware of the clinical significance of the test. Actually, NIPT is a highly accurate, time-consuming and expensive screening tool for women at increased risk of aneuploidy. Patients with a positive result have to be submitted for invasive prenatal diagnosis, such as amniocentesis or chorionic villus sampling.2 Unlike traditional screening, there is a test failure rate (range 1.6–13.0%), so women with failed tests are offered a prenatal inva-
ª 2014 Royal College of Obstetricians and Gynaecologists
sive diagnosis or a second-trimester screening test (the quadruple test), and are treated as positive only if this test is positive.4 Indeed test failure could reduce accuracy, which is reported as over 99% in the survey by Lewis and colleagues,1 and reduce the time available for the expectant parents to make important choices. Moreover, survey respondents should be made aware of costs and the time it takes to receive the results of NIPT, and this ought then to be reflected in findings that are more comparable to the choices that patients actually make in practice. Merging NIPT into the current prenatal screening pathway in the National Health Service seems to be feasible. Wald and colleagues4 proposed a screening model that should minimise false positives at a substantially lower cost than universal DNA testing. In our opinion, observational studies are an interesting way of assessing views about NIPT among potential service users. Nevertheless, counselling should be provided for the survey respondents to obtain more reliable figures about likely uptake and the possibility of merging DNA sequencing methods into the current prenatal screening pathway in the National Health Service. & References 1 Lewis C, Hill M, Silcock C, Daley R, Chitty L. Non-invasive prenatal testing for trisomy 21: a cross-sectional survey of service users’ views and likely uptake. BJOG 2014;121: 582–94. 2 American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 545: noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol 2012;120:1532–4. 3 Hill M, Barrett AN, White H, Chitty LS. Uses of cell free fetal DNA in maternal circulation. Best Pract Res Clin Obstet Gynaecol 2012;26: 639–54. 4 Wald NJ, Bestwick JP. Incorporating DNA sequencing into current prenatal screening practice for Down’s syndrome. PLoS One 2013;8:e58732.
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