Letters to the Editor

Transcription

1 Acta Anaesthesiol Scand 2012; 56: Printed in Singapore. All rights reserved 2012 The Authors Acta Anaesthesiologica Scandinavica 2012 The Acta Anaesthesiologica Scandinavica Foundation ACTA ANAESTHESIOLOGICA SCANDINAVICA Rocuronium and sugammadex for rapid sequence induction of obstetric general anaesthesia doi: /j x Williamson and colleagues description of their successful use of rocuronium for rapid sequence induction with subsequent reversal using sugammadex in an obstetric cohort 1 is interesting for a number of reasons. Firstly, the paper states that the mean duration of action of rocuronium at a dose of 1.2 mg/kg is min and that this is significantly longer than most obstetric procedures. However, the authors own results demonstrate a mean time from administration to reversal of rocuronium of 62 min, which although not supporting their assertion regarding duration of obstetric procedures, does seem to provide evidence for an extended duration of action of rocuronium in the obstetric patient. Secondly, in referring to a case series of seven obstetric patients who received rocuronium at a lower dose of 0.6 mg/kg, 2 the authors state that a dose of sugammadex of 3 mg/kg is not supported by the literature. Profound (deep) block has been described as being present when there is a post-tetanic count (PTC) of two or less for which the recommended dose of sugammadex for reversal is 4 mg/kg. Moderate (shallow) block is described as being present when the train-of-four count is two or more responses and the recommended dose of sugammadex for reversal is 2 mg/kg. 3 Very often the block is somewhere between these points, as in Williamson et al. s series where 7/17 patients had a PTC of > 2 but a train-of-four response of < 2. Consideration of dose-response curves 4 suggests a reversal dose of 3 mg/kg may be appropriate particularly when, as in the authors hospital, normal practice involves careful monitoring of neuromuscular function and also bearing in mind the current expense of sugammadex. Thirdly, in discussing the use of rocuronium and sugammadex in place of suxamethonium, the authors highlight the fact that with rocuronium, multiple intubation attempts can occur without deterioration of the intubating conditions. Recently published guidelines suggest that multiple attempts at intubation in the obstetric setting are to be avoided and that each attempt should be completed within 1 min. 5 Some authors advise no more than two attempts in the obstetric patient. 6 Our concern is that the use of rocuronium may lead the anaesthetist to lose situational awareness and become fixated upon trying to intubate rather than proceeding along a failed intubation pathway. One could argue that the fact that suxamethonium wears off spontaneously after 7 10 mins is advantageous as this allows plenty of time for two intubation attempts and also gives a visual reminder that it is time to abandon intubation. Finally, we congratulate the authors on their work in moving forward our understanding of the place of rocuronium/ sugammadex in obstetric anaesthesia and we also look forward to further studies in this area. We declare no conflict of interest. G. Kessell J. N. Trapp 1. Williamson RM, Mallaiah S, Barclay P. Rocuronium and sugammadex for rapid sequence induction of obstetric general anaesthesia. Acta Anaesthesiol Scand 2011; 55: Pühringer FK, Kristen P, Rex C. Sugammadex reversal of rocuronium-induced neuromuscular block in Caesarean section patients: a series of seven cases. Br J Anaesth 2010; 105: Abrishami A, Ho J, Wong J, Yin L, Chung F. Sugammadex, a selective reversal medication for preventing postoperative residual neuromuscular blockade. Cochrane Database Syst Rev 2009; (4): CD Groudine SB, Soto R, Lien C, Drover D, Roberts K. A randomized, dose-finding, phase II study of the selective relaxant binding drug, sugammadex, capable of safely reversing profound rocuronium-induced neuromuscular block. Anesth Analg 2007; 104: Mhyre J, Healy D. The unanticipated difficult intubation in obstetrics. Anesth Analg 2011; 112: Stacey M. Failed intubation in obstetrics. Anaesth Intensive Care Med 2004; 5: G. Kessell Department of Anaesthesia The James Cook University Hospital Marton Road Middlesbrough TS4 3BW UK gareth.kessell@stees.nhs.uk Response to Kessell and Trapp doi: /j x We would like to thank Drs Kessell and Trapp for their interest in our article. 1 With regard to their first point, it is well recognised that aminosteroid muscle relaxants have a longer duration of action in pregnancy. As we state in our discussion, this is thought to be due to relative hepatic hypoperfusion... as well as increased protein binding and competition with steroidal hormones for hepatic binding sites. 2,3 Our mean procedure duration of 62 min perhaps reflects that a large proportion of the procedures were performed by non-consultant surgeons as well as the complexity of some of the cases. The initial trials of sugammadex 4 mg/kg for reversal of deep neuromuscular blockade strictly controlled the post-tetanic 394

2 count to one to two twitches by administration of further doses of rocuronium if required; 4 whereas the trials for shallow block used sugammadex 2 mg/kg at the reappearance of the second twitch on train of four (TOF). We acknowledge that there is a large gap between these two clinical points and it may be that alternative doses, particularly when used with continuous TOF monitoring, will in time be shown to be more appropriate, but we stand by our statement that 3 mg/kg is not (yet) supported by the literature. Pragmatically, it is likely that other doses will become widespread as the use of the drug increases and it may be that sugammadex is eventually given in 200 mg aliquots (i.e. one 2-ml vial) with continuous neuromuscular monitoring for patients in this twilight zone between deep and shallow block. However until we have more experience of the drug is it worth risking underdosing the reversal? We agree that it is important to avoid fixation errors in difficult intubation and that in obstetrics in particular it is important to be clear when to bail out and wake the patient up. However there will always be patients where the best course of action is to maintain anaesthesia (such as control of obstetric haemorrhage). In this group of patients if tracheal intubation is difficult a rocuronium-induced block will offer a higher chance of subsequent success than a decaying suxamethonium block. In the event of failure to intubate the trachea, ventilation of the patient s lungs may be more easily achieved with profound neuromuscular blockade than with partial suxamethonium blockade also. We do not suggest that inexperienced anaesthetists should abandon their familiar rapid sequence induction drugs for caesarean section but that the experienced anaesthetist may find some advantages to using rocuronium in place of suxamethonium for this indication. Conflict of interest: none declared. R. M. Williamson S. Mallaiah P. Barclay 1. Williamson RM, Mallaiah S, Barclay P. Rocuronium and sugammadex for rapid sequence induction of obstetric general anaesthesia. Acta Anaesthesiol Scand 2011; 55: Puhringer FK, Sparr HJ, Mitterschiffthaler G, Agoston S, Benzer A. Extended duration of rocuronium in postpartum patients. Anesth Analg 1997; 84: Ward SJ, Rocke DA. Neuromuscular blocking drugs in pregnancy and the puerperium. Int J Obstet Anesth 1998; 7: Jones RK, Caldwell JE, Brull SJ, Soto RG. Reversal of profound rocuronium-induced blockade with sugammadex: a randomized comparison with neostigmine. Anesthesiology 2008; 109: Dr Roy M Williamson Royal Alexandra Hospital Corsebar Road Paisley PA2 9PN UK roymwilliamson@msn.com Wound catheters for post-operative pain management: overture or finale? doi: /j x In their editorial based on a meta-analysis on local anaesthetic wound infiltration, Möiniche and Dahl conclude: Do not waste any more time on clinical trials (or meta-analysis). of wound infiltration with local anaesthetics after in particular major surgical procedures be it with or without catheters the analgesic effect, if any is not clinically relevant. 1 Such a categorical statement in a scientific journal is simply invalid because it ignores results of another meta-analysis 2 and the evidence-based recommendations from Australasia 3 and the procedure-specific postoperative pain management group (PROSPECT) collaborative group. 4 Moreover, they contradict their own previous reviews on the topic. In a 2009 review of literature on the local anaesthetic infiltration for major abdominal and orthopaedic surgery, they repeatedly emphasised the need for further studies, 5 not meta-analysis of existing studies. The editorial accompanies a meta-analysis by Gupta et al. 6 that has serious weaknesses. First, for unclear reasons, orthopaedic patients were excluded, although some of the best results are seen using local infiltration analgesia (LIA) for major knee and hip surgery. 7,8 Second, importantly, studies with catheters, not strictly in the surgical wound, have also been excluded. Currently, wound catheter infusion (WCI) technique also includes catheters placed through the incision in deeper layers/cavities, for example, subfascial, peritoneal, subacromial, intraosseus, and intra-articular. Excluding these may make meta-analysis easier and scientifically more satisfying but does not reflect clinical reality. Möiniche and Dahl debate statistical considerations between qualitative and quantitative meta-analysis but neither discuss nor evaluate the impact of these. The editorial condemns wound infiltration analgesia as clinically irrelevant, in contrast to the published evidence. Liu et al. meta-analysed 44 randomised controlled trials (RCTs) concluding The most notable feature was the consistent evidence of these benefits across a wide range of surgical procedures, location of wound catheters, and dosing regimens accompanied with low incidences of catheter-related complications. Both the efficacy and technical simplicity of this technique encourage its widespread clinical use. 2 WCI was recommended in the second (2005) and third (2010) editions of Australian and New Zealand College of Anaesthetists manual based on growing level 1 evidence. 3 The evidence-based PROSPECT currently recommends wound infiltration for inguinal herniotomy, laparoscopic cholecystectomy, hysterectomy, open colon surgery, haemorroidectomy 4 and may include more procedures as its database is updated. Well-controlled studies demonstrate that pre-peritoneal catheter placement is highly effective after open colectomy, 9 subfascial placement is as effective as epidural technique after Caesarean section, 10 and LIA with intra-articular placement is superior to epidural technique for lower limb arthroplasty 7 and to intrathecal morphine for knee replacement. 8 Currently, LIA technique is used in 75% of all knee arthroplasties in Sweden. 11 As another editorial in the same issue of the journal states Further studies and work on LIA should be encouraged, also because there are very little data on LIA being inferior to even the most efficient alternative methods of systemic analgesia. 12 Infiltrative techniques with and without catheters are simple and safe and effective for many but not all procedures. There is 395

3 a definite need for head-to-head comparison with alternative analgesic techniques to identify the most cost-effective modality for different procedures. Thus, WCI is an overture, Möiniche and Dahl s editorial is a finale without an overture. Conflicts of interest: Narinder Rawal has served on advisory boards of Baxter, Pfizer and Merck and received speakers honoraria from Sintetica. Alain Borgeat has served on the advisory boards of Baxter, Pfizer and AstraZeneca. Nick Scott has received speakers honoraria from Biomet and BBraun. N. Rawal A. Borgeat N. Scott 1. Möiniche S, Dahl JB. Wound catheters for post-operative pain management: overture or finale? Acta Anaesthesiol Scand 2011; 55: Liu SS, Richman JM, Thirlby RC, Wu CL. Efficacy of continuous wound catheters delivering local anesthetic for postoperative analgesia: a quantitative and qualitative systematic review of randomized controlled trials. J Am Coll Surg 2006; 203: Macintyre PE, Schug SA, Scott DA, Visser EJ, Walker SM, Working group of the Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine. Acute Pain Management: Scientific evidence, 3rd edn Prospect Working Group. Procedure-specific postoperative pain management. Avaialble at Accessed 10 October Dahl JB, Möiniche S. Relief of postoperative pain by local anaesthetic infiltration: efficacy for major abdominal and orthopaedic surgery. Pain 2009; 143: Gupta A, Favaios S, Perniola A, Magnuson A, Berggren L. A 7. Rawal N. Local infiltration analgesia and other multicomponent techniques to improve postoperative outcome are we comparing oranges and apples? Reg Anesth Pain Med 2011; 36: Essving P, Axelsson K, Åberg E, Spännar H, Gupta A, Lundin A. Local infiltration analgesia versus intrathecal morphine after total knee arthroplasty: a randomized controlled trial. Anesth Analg 2011; 113: Beaussier M, El Ayoubi H, Schiffer E, Rollin M, Park Y, Mazoit J-X, Azizi L, Gervaz P, Rohr S, Biermann C, Lienhart A, Eledjam J-J. Continuous preperitoneal infusion of ropivacaine provides effective analgesia and accelerates recovery after colorectal surgery. A randomized, double-blind, placebo-controlled study. Anaesthesiology 2007; 107: Ranta PO, Ala-Kokko TI, Kukkonen JE, Reponen PK, Rawal N. Incisional and epidural analgesia after caesarean delivery: a prospective, placebo-controlled, randomized clinical study. Int J Obstet Anesth 2006; 15: The Swedish Knee Arthroplasty Register. Annual Report Available at Accessed 15 September Raeder J, Spreng UJ. Local-infiltration anaesthesia (LIA): post-operative pain management revisited and appraised by the surgeons? Acta Anaesthesiol Scand 2011; 55: Narinder Rawal Department of Anaesthesiology and Intensive Care University Hospital Örebr Sweden narendra.rawal@orebroll.se Is a negative meta-analyses consisting of heterogenic studies on wound catheters sufficient to conclude that no additional studies are needed? doi: /j x We read the recent meta-analysis by Gupta et al. 1 and the accompanying editorial 2 in Acta Anaesthesiologica Scandinavica with great interest. As experienced investigators in this field, we would challenge the conclusions drawn by the authors of these two articles. Gupta et al. 1 initiated their literature review based on an earlier meta-analysis evaluating the efficacy of continuous wound infiltration (CWI) of local anaesthetics published in 2006 by Liu et al. 3 Gupta et al. 1 attempted to update these previously published data, and they also tried to avoid pooling data from different surgical models (a factor that might have introduced bias in interpreting the earlier findings). At first glance, this approach would appear to be laudable and scientifically valid. However, we were disappointed because of the limited number of new studies included in this analysis of published studies since Despite the efforts of Gupta et al. 1 to minimize potential bias, the validity of combining studies involving aortic surgery, prostatectomy, cholecystectomy, appendectomy and colorectal surgery is highly questionable. They are not all considered to be major abdominal surgery and would be expected to be associated with different types (and severity) of post-operative pain. More importantly, the data extraction process could also be questioned. For example, the results on pain intensity at 24 h from the study by White et al. 4 were those obtained with the lower (and less effective) concentration of bupivacaine. A significant concentration effect was demonstrated in this study, with the 0.5% bupivacaine concentration being significantly more effective than the 0.25% concentration. More importantly, Gupta et al. failed to include a truly positive study on repeated bolus doses of ropivacaine at the donor site of abdominal flaps for breast reconstruction. 5 Albeit problematic, these concerns are not the primary purpose in writing this Letter to the Editor. We feel strongly that important information about optimal catheter placement, delivered flow rate (i.e. fluid volume), local anaesthetic concentrations and use of adjunctive drugs (e.g. non-steroidal antiinflammatory drugs, alpha-2 agonists) is lacking for many surgical procedures. Not surprisingly, subcutaneous placement of the local anaesthetic infusion catheter after abdominal laparotomy and other major surgery procedures is often ineffective, or at best, poorly effective. A recent comparative study 6 confirmed an earlier study by Yndgaard and colleagues 7 dem- Marc Beaussier received speaker fees for conferences on wound infiltration by Baxter. 396

4 onstrating that subfascial placement is associated with better efficacy than subcutaneous placement. Is it appropriate (or advisable) to combine these data in a single subgroup? Local anaesthetic flow rate is another important concern. In the study by Wu et al., 8 which was included in Gupta s metaanalysis, patients undergoing radical retropubic prostatectomy were administered a 2 ml/h flow rate of bupivacaine. It is highly likely that the pain-related outcomes might have been significantly better if these authors had used a more standard 10 ml/h flow rate. In our opinion, more well-controlled clinical studies are clearly needed before drawing definite conclusions regarding the safety and efficacy of CWI. Rather than performing more meta-analyses of small, often underpowered heterogeneous clinical trials which lead to predictably negative results, we need more well-controlled, large-scale prospectively randomized clinical trials (RCTs) to evaluate the factors which influence the efficacy of CWI. 9 Thus, we strongly disagree with the conclusion of the accompanying Editorial by Møiniche and Dahl, 2 and would encourage clinical investigators to perform adequately powered, welldesigned RCTs on CWI. In checking the U.S. National Institutes of Health clinical trial register, it would appear that a large number of potentially high-quality clinical trials involving wound infiltration are currently being conducted.* Hopefully, these studies will be completed and will provide answers to the many questions regarding the efficacy of CWI on a procedurespecific basis. M. Beaussier P. F. White J. Raeder 1. Gupta A, Favaios S, Perniola A, Magnuson A, Berggren L. A 2. Moiniche S, Dahl JB. Wound catheters for post-operative pain management: overture or finale? Acta Anaesthesiol Scand 2011; 55: Liu S, Richman J, Thirlby R, Wu C. Efficacy of continuous wound catheter delivering local anesthetic for postoperative analgesia: a quantitative and qualitative systematic review of randomized controlled trials. J Am Coll Surg 2006; 203: White P, Rawal S, Latham P, Markowitz S, Issioui T, Chi L, Dellaria S, Shi C, Morse L, Ing C. Use of a continuous local anesthetic infusion for pain management after median sternotomy. Anesthesiology 2003; 99: Utvoll J, Beausang-Linder M, Mesic H, Raeder J. Improved pain relief using intermittent bupivacaine injections at the donor site after breast reconstruction with deep inferior epigastric perforator flap. Anesth Analg 2010; 110: Rackelboom T, Le Strat S, Silvera S, Schmitz T, Bassot A, Goffinet F, Ozier Y, Beaussier M, Mignon A. Improving continuous wound infusion effectiveness for postoperative analgesia after cesarean delivery: a randomized controlled trial. Obstet Gynecol 2010; 116: * [Accessed 23 November 2011]. 7. Yndgaard S, Holst P, Bjerre-Jepsen K, Thomsen C, Struckmann J, Mogensen T. Subcutaneously versus subfascially administered lidocaine in pain treatment after inguinal herniotomy. Anesth Analg 1994; 79: Wu C, Partin A, Rowlingson A, Kalish M, Walsh P, Fleisher L. Efficacy of continuous local anesthetic infusion for postoperative pain after radical retropubic prostatectomy. Urology 2005; 66: White PF, Kehlet H. Postoperative pain management and patient outcome: time to return to work! Anesth Analg 2007; 104: Dr Marc Beaussier Département d Anesthésie-Réanimation chirurgicale Hopital St-Antoine 184 rue du Fbg St-Antoine Paris Cedex 12 France marc.beaussier@sat.aphp.fr Wound catheters for post-operative pain management: overture or finale? Answer for letters to the editor doi: /j x We thank Dr Rawal and colleagues and Dr Beaussier and colleagues for their respective commentaries. One aim of our editorial was to foster some debate on the use of wound catheters with local anaesthetics for post-operative pain management, and we appreciate these responses. The analysis by Gupta and co-workers 1 does not focus on orthopaedic procedures, nor did we in our comment. However, we admit that this could have been highlighted in the title of our editorial. As emphasised in the editorial, 2 we believe that it is extremely important not to mix apples and oranges in a meta-analysis. Accordingly, we would not consider it appropriate to mix studies of very different procedures as we believe that wound pain, or effects of a wound catheter, following for instance major abdominal surgery and (minor) subacromial procedures are not necessarily comparable. Furthermore, we would not consider it appropriate to mix studies of wound catheter infusion techniques of quite different structures such as subcutaneous or subfascial areas of the wound, the peritoneal cavity, etc. In their analysis, Gupta and co-workers 1 seek to avoid such assortments and we believe they deserve credit for this approach. In our opinion, results from very different procedures or very different techniques of local anaesthetic infusion cannot just be extrapolated or transferred between each other, and this would not reflect clinical reality. In our editorial 2 we have seek to explain that one of the reasons for the observed differences in results from the metaanalyses performed by Gupta et al. 1 and the meta-analyses performed by Liu et al. 3 may be mixing of very different procedures in the latter analysis. Accordingly, we appreciate the balanced views expressed by Dr Beaussier and colleagues in their letter to the editor concerning the comparability of included studies. On 397

5 the other hand, we disagree with the points made by Dr Rawal and colleagues. Although we fully respect and are aware of the recommendations from the Australian and New Zealand College of Anaesthetists, 4 we have to stress that the level 1 evidence on wound infiltration in Acute Pain Management: Scientific Evidence 4 is based exactly on Liu s meta-analysis. 3 From the available literature it will be possible for both proponents and opponents of wound catheters with local anaesthetics to refer to individual papers supporting their particular points of view as demonstrated by this debate. We just have to admit that we are among the sceptical opponents. 5 We do agree with many of the recommendations made by PROSPECT.* It should be noted that PROSPECT does not recommend wound infiltration for major (colonic) surgery, and their advice regarding wound infiltration after abdominal hysterectomy is not clear cut. Whether there is a need for further adequate-powered, well-designed randomised clinical trials as pointed out by Dr Beaussier and colleagues may be argued. We are still sceptical with respect to such needs and feel that it is time to move in new directions. Conflict of interest: none S. Møiniche J. B. Dahl *Procedure-specific postoperative pain management (PROSPECT) (Accessed 5 January 2012) 1. Gupta A, Favaios S, Perniola A, Magnuson A, Berggren L. A 2. Møiniche S, Dahl JB. Wound catheters for post-operative pain management: overture or finale? Acta Anaesthesiol Scand 2011; 55: Liu SS, Richman JM, Thirlby RC, Wu CL. Efficacy of continuous wound catheters delivering local anesthetic for postoperative analgesia: A quantitative and qualitative systematic review of randomized controlled trials. J Am Coll Surg 2006; 203: Macintyre PE, Schug SA, Scott DA, Visser EJ, Walker SM, Working group of the Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine. Acute Pain Management: Scientific evidence (3rd edition). ceoanzca@edu.au Dahl JB, Møiniche S. Relief of postoperative pain by local anaesthetic infiltration. Efficacy for major abdominal and orthopaedic surgery. Pain 2009; 143: Steen Møiniche Department of Anaesthesiology Glostrup Hospital Nordre Ringvej Copenhagen DK-2600 Denmark stemoe01@glo.regionh.dk 398