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- Ester Forastiere, Maria Sofra (7 April 2009)
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Low dose infusion with "Surgical TAP block" in open nephrectomy
- Rav Harish (13 March 2009)
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Ester Forastiere , Maria Sofra
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We thank the Author for the opportunity of clarifying some aspects about the multimodal analgesia. We proved that two catheters placed between muscles and into the subcutaneous space, respectively, provide an excellent pain relief. We also highlighted how this technique, as part of a multimodal approach to postoperative pain, allows to reduce side effects optimizing the effectiveness of the wound infusion - thanks to the effects on two different nociceptors and so on different “pain pathways”. This is probably the most original aspect of our experience, so, since the On-Q device has two Soaker catheters we would suggest not to spend time thinking about which one of the two catheters provides the major benefit. Concerning the toxicity threshold we cannot agree about 200mg as threshold for ropivacaine. to our knowledge the range of toxicity for this drug could be between 600 and 660 mg/day. Anyway, the absence of clinically significant side effects in our study is an evidence obtained by a long term experience in patients undergoing open nephrectomies, prostatectomies, and cystectomies. In all patients the drug dose was 480mg/day. Ethical challenges do not exist, and when it does the measurement of serum levels of the administered drug should be performed in a preliminary analysis, just as we did. We really hope that on these bases measuring ropivacaine levels in further studies will be considered an unuseful extra-cost. Finally, concerning the case reported by the Authors, we really question the utility of submitting patients to two different invasive approaches (epidural and TAP block), since our device proved to be effective, safe and probably “less invasive” than the surgical TAP block. We hope that further techniques of postoperative pain management will be compared with ours, which represents a standard treatment in our Department - thanks to its reproducibility and to its effectiveness. Conflict of Interest:None declared |
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Rav Harish, Consultant Anaesthetist (L)
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To the Editor, I read with interest and would like to commend the study by Forastiere et al(1) showing a simple, efficient and cost-effective method of postoperative pain relief with wound infusion of local anaesthetic after open nephrectomy. There are two interesting aspects of the study I like to comment. Firstly, despite the evidence of effectiveness of local anaesthetic subcutaneous wound infusion after laparotomy being controversial(2,3), the author employed it as one of the study arm along with the muscular layer infusion. This probably does not allow one to judge as to which catheter infusion provided the actual post-operative benefits. Secondly, one of the many unanswered questions in all the studies in literature is the ideal volume and concentration of local anaesthetics used. The overall dosage of ropivacaine used in this study would equate to a total of 480 mg per day through both catheters for a period of 48hrs. This compared to safe allowable daily dosage in literature being maximum of 200mg, it could be ethically challenged on drug safety issues and risk of toxicity. However, there were no reports of toxicity in the study despite ropivacaine levels not measured. We would like to describe our case report of an 83 yr old female patient, who underwent open nephrectomy for tumour. She received a thoracic epidural, inserted before general anaesthesia for intraoperative analgesia, with 10mls of 0.125% bupivacaine with 1mg diamorphine. Since it was not feasible to continue epidural postoperatively, a 16 gauge epidural catheter was inserted through the top end of the wound at closure and placed between the transverse abdominis and internal oblique muscle layers. The technique as we like to refer to as "Surgical TAP block" (TAP- transverse abdominis plane block) was commenced post operatively with 5 ml/hr of 0.15% bupivacaine infusion using an elastomeric pump for 36 hrs. The patient postoperative pain relief was excellent with no recourse to any strong opioid until the catheter was removed on request after 36 hrs. We agree with the author that further studies need to look at comparing S.C plane to muscular plane catheters for efficacy with various local anaesthetic dosages. We hope that our report will be of some benefit in basing dosage regimes in further studies relating to open nephrectomy. References 1. E. Forastiere, M. Sofra, D. Giannarelli, L. Fabrizi, and G. Simone: Effectiveness of continuous wound infusion of 0.5% ropivacaine by On-Q pain relief system for postoperative pain management after open nephrectomy Br. J. Anaesth. 2008 101: 841-847 2. Fredman B, Zohar E, Tarabyki A, Shapiro A, Mayo A, Klein E, Jedeikin R: Bupivacaine wound instillation via an electronic patient-controlled analgesia device and a double-catheter system does not decrease postoperative pain or opioid requirement after major abdominal surgery. Anesth Analg 2001; 92:189-93 3. Cheong W, Seow-Choen F, Eu K, Tang C, Heah S: Randomized clinical trial of local bupivacaine perfusion versus parenteral morphine infusion for pain relief after laparotomy. Br J Surg 2001; 88:357-9 Dr Rav Harish Consultant Anaesthetist (L), Swansea, Wales Email: hsirah02@hotmail.com Conflict of Interest:None declared |
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