Anaesthesia 2014, 69, 785–798
Correspondence Timing of post-dural puncture headache symptoms I read with interest the paper by Stein et al. [1] comparing prophylactic and therapeutic epidural blood patch administration for accidental dural puncture in the obstetric population. I noticed that the range of times between accidental dural puncture and administration of the prophylactic epidural blood patch varied from 5 h to 30 h. As postdural puncture headache (PDPH) can occur almost instantaneously [2], with symptoms beginning before 48 h in 66% of cases [3], I wondered if the authors could clarify whether any symptoms of PDPH had occurred in the patients who received their treatment towards 30 h after accidental dural puncture, effectively re-classifying their blood patch as therapeutic rather than prophylactic? M. Daunt Nottingham University Hospitals, NHS Trust, Nottingham, UK Email: [email protected]
No external funding and no competing interests declared. Previously posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
References 1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture – a randomised controlled trial. Anaesthesia 2014; 69: 320–6. 2. Weir EC. The sharp end of the dural puncture. British Medical Journal 2000; 320: 127–8. 3. Leibold RA, Yealy DM, Coppola M, Cantees KK. Post-dural-puncture headache: characteristics, management, and prevention. Annals of Emergency Medicine 1993; 22: 1863–70. doi:10.1111/anae.12728
Accidental dural puncture: patch or wait? The randomised controlled trial of prophylactic versus therapeutic blood patching following accidental dural puncture by Stein et al. [1] is a useful addition to the literature on this subject. However, we would like answers to a number of questions before we can agree with the authors’ conclusion, that “prophy-
lactic epidural blood patch is an effective method to reduce the development of post-dural puncture headache”. Their data appear to support existing evidence [2] that delayed epidural blood patch has a non-significantly higher first-time, headache-free success rate compared with early administration (81.7% vs 88.9%, p = 0.399). The authors interpret data presented in Table 2 of their paper as showing that “the intensity of the headache and accompanying symptoms were reduced” in women who received a prophylactic rather than a therapeutic blood patch. However, this is a false comparison, as one group had already received an intervention (prophylactic blood patch) and the other had not (therapeutic blood patch) at the time when the prevalence of the outcome (dural puncture headache) was assessed, so is not a valid assessment of either intervention’s comparativeness. This conclusion is further weakened by 13/49 (26.5%) of the ‘therapeutic’ group’s having been treated using only conservative measures. These patients might be
A response to a previously published article or letter must be submitted via the dedicated correspondence website at www.anaesthesiacorrespondence.com, following the guidance there and using the online form (not uploaded as a Word attachment). Please note that a selection of this correspondence will be reproduced (possibly in modified form) in the Journal. Correspondence on new topics should be submitted as an email attachment to [email protected]. Copy should be prepared in the usual style of the Correspondence section. Authors must follow the Guidance for Authors at wileyonlinelibrary.com/journal/anae, including completion and submission of an Author Declaration Form. © 2014 The Association of Anaesthetists of Great Britain and Ireland
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Anaesthesia 2014, 69, 785–798
expected to have experienced minor headache symptoms compared with patients administered blood patch, and should have been excluded from this analysis, in our opinion. Indeed, these women could be considered ‘treatment successes’, since they received analgesia sufficient to be able to continue childcare at home, headache-free at one week, without exposure to the risks of epidural blood patch. It follows that a similar proportion of the ‘prophylactic’ group might have had these outcomes had they been managed conservatively, but were exposed to those risks, in the event. Extrapolated to our anaesthetic department, the author’s data suggest that 18 prophylactic blood patches per 100 women could be administered unnecessarily to women who might otherwise receive conservative management to achieve the endpoint of ‘no headache at one week’. D. Hewson G. Graham Guy’s and St Thomas’ NHS Foundation Trust, London, UK Email: [email protected] No external funding and no competing interests declared. Previously posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
Correspondence ients. International Journal of Obstetric Anesthesia 2013; 22: 303–9. doi:10.1111/anae.12743
References Aseptic precautions for epidural blood patch I read the article by Stein and colleagues [1], and noted their impressive results with great interest. I have two queries regarding the aseptic precautions used in their study. It is recognised that epidural blood patch should be performed with the highest standard of asepsis [2], and I note that blood was infused through an epidural catheter that had been in situ, in some cases for up to 30 hours. Presumably the bacterial filter had to be removed before injecting the blood, so I wonder if the authors could eludicate how they ensured meticulous asepsis of the epidural catheter hub before connecting the syringe? Secondly, women who have recently delivered vaginally may have bacteraemia [3], and meningitis has been reported previously as a complication of epidural blood patch [4]. What measures did the authors take before the blood patch to assess patients for bacteraemia or sepsis? Related to this point, were any patients deemed to be at a high risk of infective complications and therefore denied the procedure?
References 1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture–a randomised controlled trial. Anaesthesia 2014; 69: 320–6. €vall S, Kein€anen M, Kokki H. 2. Kokki M, Sjo The influence of timing on the effectiveness of epidural blood patches in partur786
posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
R. M. Williamson Royal Alexandra Hospital, Paisley, Scotland Email: [email protected] No external funding and no competing interests declared. Previously
1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture - a randomised controlled trial. Anaesthesia 2014; 69: 320–6. 2. Reynolds F. Dural puncture and headache. British Medical Journal 1993; 306: 874–6. 3. Tower C, Nallapeta S, Vause S. Prophylaxis against infective endocarditis in obstetrics: new NICE guidance: a commentary. British Journal of Obstetrics and Gynaecology 2008; 115: 1601–04. 4. Berga S, Trierweiler MW. Bacterial meningitis following epidural anaesthesia for vaginal delivery: a case report. Obstetrics and Gynecology 1989; 74: 437–9. doi:10.1111/anae.12744
A reply I would like to thank all the authors for their insightful comments regarding our paper [1]. There were very few instances where a prophylactic epidural blood patch was administered around 30 hours after dural puncture. Those cases, to the best of my recollection, involved prolonged induction of labour, or failed labour with resultant caesarean delivery. In such cases, the interval from dural puncture (performed early in labour) until prophylactic blood patch was necessarily lengthy. Unfortunately, we only recorded whether a patient experienced vaginal or caesarean delivery, and not record whether a patient experienced spontaneous or induced labour, or whether labour failed with resultant caesarean delivery rather than elective caesarean delivery.
© 2014 The Association of Anaesthetists of Great Britain and Ireland
Correspondence Timing of post-dural puncture headache symptoms I read with interest the paper by Stein et al. [1] comparing prophylactic and therapeutic epidural blood patch administration for accidental dural puncture in the obstetric population. I noticed that the range of times between accidental dural puncture and administration of the prophylactic epidural blood patch varied from 5 h to 30 h. As postdural puncture headache (PDPH) can occur almost instantaneously [2], with symptoms beginning before 48 h in 66% of cases [3], I wondered if the authors could clarify whether any symptoms of PDPH had occurred in the patients who received their treatment towards 30 h after accidental dural puncture, effectively re-classifying their blood patch as therapeutic rather than prophylactic? M. Daunt Nottingham University Hospitals, NHS Trust, Nottingham, UK Email: [email protected]
No external funding and no competing interests declared. Previously posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
References 1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture – a randomised controlled trial. Anaesthesia 2014; 69: 320–6. 2. Weir EC. The sharp end of the dural puncture. British Medical Journal 2000; 320: 127–8. 3. Leibold RA, Yealy DM, Coppola M, Cantees KK. Post-dural-puncture headache: characteristics, management, and prevention. Annals of Emergency Medicine 1993; 22: 1863–70. doi:10.1111/anae.12728
Accidental dural puncture: patch or wait? The randomised controlled trial of prophylactic versus therapeutic blood patching following accidental dural puncture by Stein et al. [1] is a useful addition to the literature on this subject. However, we would like answers to a number of questions before we can agree with the authors’ conclusion, that “prophy-
lactic epidural blood patch is an effective method to reduce the development of post-dural puncture headache”. Their data appear to support existing evidence [2] that delayed epidural blood patch has a non-significantly higher first-time, headache-free success rate compared with early administration (81.7% vs 88.9%, p = 0.399). The authors interpret data presented in Table 2 of their paper as showing that “the intensity of the headache and accompanying symptoms were reduced” in women who received a prophylactic rather than a therapeutic blood patch. However, this is a false comparison, as one group had already received an intervention (prophylactic blood patch) and the other had not (therapeutic blood patch) at the time when the prevalence of the outcome (dural puncture headache) was assessed, so is not a valid assessment of either intervention’s comparativeness. This conclusion is further weakened by 13/49 (26.5%) of the ‘therapeutic’ group’s having been treated using only conservative measures. These patients might be
A response to a previously published article or letter must be submitted via the dedicated correspondence website at www.anaesthesiacorrespondence.com, following the guidance there and using the online form (not uploaded as a Word attachment). Please note that a selection of this correspondence will be reproduced (possibly in modified form) in the Journal. Correspondence on new topics should be submitted as an email attachment to [email protected]. Copy should be prepared in the usual style of the Correspondence section. Authors must follow the Guidance for Authors at wileyonlinelibrary.com/journal/anae, including completion and submission of an Author Declaration Form. © 2014 The Association of Anaesthetists of Great Britain and Ireland
785
Anaesthesia 2014, 69, 785–798
expected to have experienced minor headache symptoms compared with patients administered blood patch, and should have been excluded from this analysis, in our opinion. Indeed, these women could be considered ‘treatment successes’, since they received analgesia sufficient to be able to continue childcare at home, headache-free at one week, without exposure to the risks of epidural blood patch. It follows that a similar proportion of the ‘prophylactic’ group might have had these outcomes had they been managed conservatively, but were exposed to those risks, in the event. Extrapolated to our anaesthetic department, the author’s data suggest that 18 prophylactic blood patches per 100 women could be administered unnecessarily to women who might otherwise receive conservative management to achieve the endpoint of ‘no headache at one week’. D. Hewson G. Graham Guy’s and St Thomas’ NHS Foundation Trust, London, UK Email: [email protected] No external funding and no competing interests declared. Previously posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
Correspondence ients. International Journal of Obstetric Anesthesia 2013; 22: 303–9. doi:10.1111/anae.12743
References Aseptic precautions for epidural blood patch I read the article by Stein and colleagues [1], and noted their impressive results with great interest. I have two queries regarding the aseptic precautions used in their study. It is recognised that epidural blood patch should be performed with the highest standard of asepsis [2], and I note that blood was infused through an epidural catheter that had been in situ, in some cases for up to 30 hours. Presumably the bacterial filter had to be removed before injecting the blood, so I wonder if the authors could eludicate how they ensured meticulous asepsis of the epidural catheter hub before connecting the syringe? Secondly, women who have recently delivered vaginally may have bacteraemia [3], and meningitis has been reported previously as a complication of epidural blood patch [4]. What measures did the authors take before the blood patch to assess patients for bacteraemia or sepsis? Related to this point, were any patients deemed to be at a high risk of infective complications and therefore denied the procedure?
References 1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture–a randomised controlled trial. Anaesthesia 2014; 69: 320–6. €vall S, Kein€anen M, Kokki H. 2. Kokki M, Sjo The influence of timing on the effectiveness of epidural blood patches in partur786
posted on the Anaesthesia correspondence website: www.anaesthesia correspondence.com.
R. M. Williamson Royal Alexandra Hospital, Paisley, Scotland Email: [email protected] No external funding and no competing interests declared. Previously
1. Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural puncture - a randomised controlled trial. Anaesthesia 2014; 69: 320–6. 2. Reynolds F. Dural puncture and headache. British Medical Journal 1993; 306: 874–6. 3. Tower C, Nallapeta S, Vause S. Prophylaxis against infective endocarditis in obstetrics: new NICE guidance: a commentary. British Journal of Obstetrics and Gynaecology 2008; 115: 1601–04. 4. Berga S, Trierweiler MW. Bacterial meningitis following epidural anaesthesia for vaginal delivery: a case report. Obstetrics and Gynecology 1989; 74: 437–9. doi:10.1111/anae.12744
A reply I would like to thank all the authors for their insightful comments regarding our paper [1]. There were very few instances where a prophylactic epidural blood patch was administered around 30 hours after dural puncture. Those cases, to the best of my recollection, involved prolonged induction of labour, or failed labour with resultant caesarean delivery. In such cases, the interval from dural puncture (performed early in labour) until prophylactic blood patch was necessarily lengthy. Unfortunately, we only recorded whether a patient experienced vaginal or caesarean delivery, and not record whether a patient experienced spontaneous or induced labour, or whether labour failed with resultant caesarean delivery rather than elective caesarean delivery.
© 2014 The Association of Anaesthetists of Great Britain and Ireland
