If you wish to respond to a paper or other item already published in the BJA, please go to the abstract/full text version of that item and click on the link "E-Letters: Submit a response to the article".
Electronic Letters to:
|
|
E-letters: Electronic letters published:
-
![[Read E-letter]](/icons/misc/sectionDOWN.gif)
Author's response
- Philip M Hopkins (1 May 2007)
-
Guided or Blinded
- Hui Yun Vivian Ip (22 April 2007)
-
Some remarks on the editorial of P.M. Hopkins in BJA march 2007
- Chris van Velzen (30 March 2007)
-
Re: Ultrasound guidance as a gold standard in regional anaesthesia
- Nigel M Bedforth, Dr Gillian L. Foxall Dr Jonathan G. Hardman (30 March 2007)
-
Ultrasound Guidance: a Response
- Belinda M Cornforth, David M Hargreaves (30 March 2007)
-
Ultrasound guidance is not yet the gold standard in regional anaesthesia.
- John A W Wildsmith (15 March 2007)
-
Frustration with Ultrasound Guidance
- Andrew G Haldane (15 March 2007)
-
Ultrasound-Guided Regional Anaesthesia: Possibly Gold But Not Yet Standard
- Colin JL McCartney (13 March 2007)
|
|
|||
|
Philip M Hopkins University of Leeds
Send letter to journal:
|
Editor. I am pleased that my editorial 1 has generated debate of the status of ultrasound guidance in regional anaesthesia. I welcome the opportunity to respond to comments concerning the evidence base for the use of ultrasound, the relative contribution to block failure of a particular technique versus human deficiencies, cost and training and the motives behind my article. Evidence-base for ultrasound guidance. In my editorial I questioned the need for randomised controlled trials of ultrasound-guided versus other regional techniques. To varying degrees McCartney, van Velzen, Wildsmith and Cornforth and Hargreaves would appear to believe that a randomised controlled comparison of ultrasound with other regional techniques is the only form of evidence that we should accept. But let us consider what makes a successful regional block. Can we not agree that this is placement of a needle adjacent to each of the relevant nerves and injection of sufficient local anaesthetic around them, while avoiding causing damage to nerves and other structures with the needle or injecting the local anaesthetic in the wrong place? To argue otherwise is to imply that there is some magical or mystical component to regional anaesthesia. I believe that there is sufficient evidence from experts in ultrasound-guided needle placement to inform us that this can be achieved with greater rates of success than even the most successful series of nerve blocks using nerve stimulator confirmation of needle placement. To ignore this substantial body of evidence for the accuracy of ultrasound-guided needle placement is akin to arguing that parachutes should not be used because their efficacy has not been demonstrated in a randomised controlled trial 2 . The evidence for the accuracy of ultrasound guided needle placement comes in the form of prospective trials, observational studies and consensus statements in the radiology literature. McCartney cites, for example, a prospective study of 2403 imaging-guided (ultrasound or stereotactic) breast biopsies that demonstrated an accuracy of > 99% using ultrasound 3. McCartney is wrong, however, in suggesting that Dillon et al 4 provide evidence that “the optimal combination of a number of endpoints can improve success”. This study compared ultrasound guided breast biopsy with clinically or stereotactically guided biopsy. The success rate was significantly higher in the ultrasound group compared to the others and the authors comment on the advantage of real-time imaging using ultrasound. Dillon et al 4 refer to one disadvantage of ultrasound in this context compared with stereotactic guidance, which concerns the inability to visualise breast biopsy sites that consist solely of calcified tissue using ultrasound: this is of no relevance to ultrasound guided regional anaesthesia. Factors contributing to block failure and complications. I enjoyed Professor Wildsmith’s letter as a masterful example of selective quotation. Rather than saying “ a clinical aid (ultrasound) will produce” successful nerve block with no complications, I did in fact suggest that “with appropriate training, experience and performance, ultrasound techniques have the potential to produce successful nerve block with no complications secondary to needle misplacement in all cases”. This is a fundamental difference to other currently employed regional techniques in which the technology does not reliably confirm perineural location of the needle, nor does it permit identification of anatomical variation. Consequently, block success and avoidance of complications with these techniques always include an element of luck, an element that ultrasound guidance eliminates. McCartney disagrees with my assertion that there are no inherent harmful effects of ultrasound guidance and yet all the examples he gives are dependent on operator deficiency as are the reports cited by Bedford and colleagues. Cornforth and Hargreaves criticise me for not recognising that we all err from perfection, yet this is precisely my point – the technique has the potential to be successful and safe, so any problems are human deficiencies. We should not be afraid to admit that human factors affect performance but we should expect to inform patients of any impact on their care, for example, our own success rates with a regional anaesthetic technique. We should also expect to demonstrate how we conduct our practice in order to minimise the risks of patients coming to harm from our inevitable human deficiencies. For example, when teaching ultrasound guided regional techniques my advice is to not proceed or to abandon the procedure at any stage if you cannot identify: the desired point(s) of injection; all the structures through which the needle has to pass; the structures to be avoided; and the real-time location of the needle throughout the procedure. I have expanded above my arguments that there is the evidence already available to question those who are not actively seeking to introduce ultrasound guidance into their regional anaesthesia practice. I did not, however, imply (strongly or otherwise) that those not using ultrasound are negligent. Rather, I suggested it might become advisable, in order to limit the potential for litigation, that when we consent patients for regional anaesthesia we explain that a range of techniques is in use and justify the use of the proposed technique. This was the approach used by orthopaedic surgeons who continued to perform open meniscectomies when the majority had adopted arthroscopic techniques. Quality, cost and availability of machines. Ip is correct to point out the need for high-resolution ultrasound images for regional anaesthetic techniques. These represent relatively large (for anaesthetic departments) capital expenditure items but colleagues needing to make a business case should be aware that a cost comparison of ultrasound guidance and nerve stimulator techniques suggested that the costs were similar 5 . The increased availability of suitable machines should also ease the frustration of trainees such as Haldane . Motives behind my article. Dr van Velzen adopts a wonderfully cynical attitude to my motives. I can assure him that there are “no strings attached” to my sponsorship from SonoSite. My views are based on my appraisal of the literature and experience of a variety of regional anaesthetic techniques. My motives are ultimately for patient benefit (I am sorry if this is not good for your residents) and to encourage readers to embrace the full range of relevant evidence. I agree with van Velzen, though, that injection of local anaesthetic into the nerve sheath may not be as harmful as previously thought. I suspect, from cases that I am aware of, that a more significant factor is direct needle damage secondary to multiple needling of a nerve. I abandoned using nerve stimulators in conjunction with ultrasound when I observed that it was not unusual for the needle tip to be directly adjacent to a nerve trunk while not eliciting a response to the nerve stimulator, illustrating the lack of sensitivity of nerve stimulation 6 . I believe this is a potential drawback of “blind techniques”. References. 1. Hopkins PM. Ultrasound guidance as a gold standard in regional anaesthesia. Br J Anaesth 2007; 99: 299-301 2. Smith GCS, Pell JP. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. Br Med J 2003; 327: 1459-61 3. Fajardo LL, Pisano ED, Caudry DJ et al. Radiologist Investigators of the Radiologic Diagnostic Oncology Group V. Stereotactic and sonographic large - core biopsy of nonpalpable breast lesions: results of the Radiologic Diagnostic Oncology Group V study. Acad Radiol 2004; 11: 293-308 4. Dillon MF, Hill AD, Quinn CM, O'Doherty A, McDermott EW, O'Higgins N. The accuracy of ultrasound, stereotactic, and clinical core biopsies in the diagnosis of breast cancer, with an analysis of false-negative cases. Ann Surg 2005; 242: 701-7 5. Sandhu NS, Sidhu DS, Capan LM. The cost comparison of infraclavicular brachial plexus block by nerve stimulator and ultrasound guidance. Anesth Analg 2004;98:267– 8 6. Perlas A, Nizi A, McCartney C, Chan V, Xu D, Abbas S. The sensitivity of motor responses to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med 2006;31:445-50 Conflict of Interest:The author has the use of ultrasound equipment loaned by SonoSite UK Ltd and has received funding from SonoSite UK Ltd for expenses relating to speaking engagements. |
|||
|
|
|||
|
Hui Yun Vivian Ip, SpR Anaesthetics
Send letter to journal:
|
Editor - I completely agree with using real-time ultrasound imaging as a gold standard in regional anaesthesia as outlined by Dr Hopkins1. In 2002, Patterson et al2 proposed that ultrasound use in peripheral nerve identification appears to offer better accuracy and safety. He acknowledged the fact that it may be technology-dependent and expensive then. There are many benefits to using ultrasound technique in performing peripheral nerve blocks such as the ability to visualize and identify the target nerve(s) and the surrounding structures which is particularly useful in patients with anatomical variations. It provides a real-time view of the path of the needle and the spread of the local anaesthetics. It minimized the risk of intra-neural injection and damaging the neighbouring structures. Ultrasound guided regional anaesthesia has been described to give a better quality block and improve the success rate 3 4. Its use is increasing especially in North America where a lot of work has been published on ultrasound guided peripheral nerve blocks. However, it is only slowly taking off here in the United Kingdom. The main problem seems to be getting a high resolution ultrasound machines which provide high quality images. In order to learn a new technique, one needs not only a good trainer but also a good set of equipments. With the low resolution ultrasound machines, the images are forever like snowstorms. It would be difficult for an expert to perform ultrasound guided blocks let alone a novice to ultrasound! Since it is important to have clear images of the target, namely, the nerve(s) and a continuous view of the needle when aiming for the ‘target’, a poor quality ultrasound machine will make it more dangerous to perform peripheral nerve blocks. Unfortunately, the higher resolution ultrasound machines are expensive. Due to the lack of funding to purchase these expensive ultrasound machines, anaesthetists are forced to abandon practising the technique despite learning about ultrasound guided regional techniques at places where there are ample of high quality ultrasound machines. Furthermore, many anaesthetists are comfortable in doing peripheral nerve blocks with a nerve stimulator which has its own problems as Hopkins pointed out in his editorial1. They have been performing the technique for many years with good results, therefore, many are reluctant to change which is understandable. Furthermore, learning a new technique can be difficult with a relatively low success rate at the initial stages. Expensive ultrasound machines further deters Consultant anaesthetists to practice the skills resulting in less trainees being given the opportunity to learn and practise the skill. As with all practical procedures, practice makes perfect and this is proving very difficult. We are in a situation where there is more litigation in medicine and the safety of our patients should always be paramount, every effort should be taken to make this possible. This is one of the reasons why ultrasound guided vascular access is one of NICE guidelines. This will no doubt open the door for ultrasound guided regional techniques eventually. However, unlike vascular access where a low resolution ultrasound probe is sufficient, a higher quality machine is needed for viewing the different structures clearly when performing peripheral nerve blocks. We are in a dilemma: ultrasound is a safe technique if done well but the unavailability of equipments means one has to continue encouraging the traditional technique of performing nerve blocks with nerve stimulators. We are not given a choice to provide our patients this potentially safer option of performing peripheral nerve blocks. Five years on from Dr Peterson’s editorial2, we remain in a situation where the high cost is limiting the immediate general availability of high quality ultrasound machine to enable regional anaesthetic techniques to be practised. Perseverance of obtaining the available equipments will enable continual development of our skills and either cost reduction or increase funding from the hospital will certainly help facilitating this ultimately. If this does not happen, the gap between the United Kingdom and the rest of the developed world in terms of advancement of our skills in ultrasound guided regional anaesthesia will continue to increase. Furthermore, we are denying patients of a safer technique of regional anaesthesia. Dr Hui Yun Vivian IP London, UK e-mail: vip@doctors.org.uk References 1. Hopkins P M. Ultrasound guidance as a gold standard in regional anaesthesia ed. Bristish Journal of Anaesthesia, 2007;98(3):299-301. 2. M. K. Peterson, F. A. Millar and D. G. Sheppard. Ultrasound-guided nerve blocks ed. British Journal of Anaesthesia, 2002;88(5):621-624. 3. Chan VW, Perlas A, McCartney CJ et al. Ultrasound guidance improves success rate of axillary brachial plexus block. Can J Anaesth. 2007;54(3):176-82. 4. Liu FC, Liou JT, Tsai YF et al. Efficacy of ultrasound-guided axillary brachial plexus block: a comparative study with nerve stimulator-guided method. Chang Gung Med J. 2005;28(6):396-402. Conflict of Interest:None declared |
|||
|
|
|||
|
Chris van Velzen, anesthesiologist
Send letter to journal:
|
Editor, After reading the editorial by P.M. Hopkins in the British Journal of Anesthesiology march 2007 I have a few remarks. First of all Hopkins state that he found only one paper, in children, that demonstrated an improved success. After that he state “is the status of ultrasound guidance in regional anesthesia to be paralyzed etc” but why does he state that. Is it because he was sponsored by SonoSite? After all it is decided that new technologies and other techniques should be based on evidenced medicine, why not in this case. If we accept this meaning for fact then we are on a wrong path, this includes the BJA. When we decide to publish meanings based on sponsored thoughts then we go back in time a long way. I challenge the idea that ultrasound should be used always. Yes it is good for the industry. No it is not good for our residents. They do not learn to use landmarks, nerve stimulation and good clinical approach of the patients who rely on the expertise of the docter. Besides these arguments we also force hospitals with a smaller budget to invest in techniques which are not better then the already functional “old” techniques. Also have to be mentioned that the presumed disadvantage of nerve stimulation that injection in the nerve sheat is dangerous might not be the truth as described by Bigeleisen. The last remark is based on the last paragraph in which Hopkins says that indeed more research and development is necessary in ultra guided regional techniques. Why should we have 3D imaging and robotarms, because SonoSite can make more money? I should say do more research to prove that ultra sound is better then nerve stimulation. And if so then it is time to reëvaluate the use of regional techniques assisted by nerve stimulation. Sincerely, C. van Velzen, anesthesiologist St Franciscus Gasthuis, Rotterdam The Netherlands Dennie NM, Harrop-Griffiths W. Location, location, location! Ultrasound imaging in regional anesthesia. Br. J. Anesth. 2005;94:1-3 Willschke H, Marhofer P, Bosenberg A et. al. Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children. Br. J. Anesth. 2005;95:226-30 Bigeleisen PE. Nerve puncture and apparent intraneural injection during ultrasound guided axillaryblock does not invariably result in neurologic injury. Anesthesiology 2006; 105:779-83 Conflict of Interest:None declared |
|||
|
|
|||
|
Nigel M Bedforth, Consultant Anaesthetist , Dr Gillian L. Foxall Dr Jonathan G. Hardman
Send letter to journal:
|
Editor- We read with interest the editorial by Hopkins (1) promoting ultrasound guidance as a gold standard for regional anaesthesia. We agree that ultrasound guidance is a significant step forward in regional anaesthesia and that it has the potential to produce successful nerve blocks while minimising complications related to needle misplacement. Unfortunately, such complications, which include vascular puncture (2,3) and intraneuronal injection,(4) have been reported during two-dimensional (2-D) ultrasound-guided nerve-blockade, and there exists the potential for further improvement. At the end of Professor Hopkins' editorial, he mentions looking forward to studies of “real-time” three-dimensional (3-D) ultrasound assisting ultrasound-guided needle placement. Such 3-D ultrasound is a relatively recent development, where an infinite number of 2-D planes of a target volume may be acquired. These 2-D planes can produce a number of viewing modalities, of which 3-D multiplanar imaging is one; in this modality, simultaneous ultrasound images in three perpendicular planes are produced in real-time. Three-dimensional ultrasound imaging has already been successfully used for needle guidance in other specialties.(5,6,7,8) We have used real-time 3-D multiplanar ultrasound to assist in the performance of a single-shot peripheral radial nerve block (9) and believe that this imaging modality has considerable potential to improve both nerve identification and accuracy of needle placement during regional anaesthesia. References: 1. Hopkins PM. Ultrasound guidance as a gold standard in regional anaesthesia. Br J Anaesth 2007; 99: 299-301 2. Sandhu NS, Capan LM. Ultrasound-guided infraclavicular brachial plexus block. Br J Anaesth 2002; 89: 254-9 3. Chan VW, Perlas A, Rawson R, Odukoya O. Ultrasound-guided supraclavicular brachial plexus block. Anesth Analg 2003; 97:1514-7 4. Schafhalter-Zoppoth I, Zeitz ID, Gray AT. Inadvertant femoral nerve impalement and intraneural injection visualizes by ultrasound. Anesth Analg 2004; 99:627-8 5. Unsgaard G, Rygh OM, Selbekk T, et al. Intra-operative 3-D ultrasound in neurosurgery. Acta Neurochir (Wien) 2006; 148:235-53 6. Delle Chiaie, Terinde R. Three-dimensional ultrasound validated large-core needle biopsy: is it a reliable method for the histological assessment of breast lesions? Ultrasound Obstet Gynecol 2004; 23:393-7 7. Fung AYC, Ayyangar KM, Djajaputra D, Nehru RM, Enke CA. Ultrasound-based guidance of intensity-modulated radiation therapy. Medical Dosimetry 2006; 31:20-9 8. Downey DB, Chin JL, Fenster A. Three-dimensional ultrasound guided cryosurgery. Radiology 1995; 197(P): 539 9. Foxall GF, Hardman JG, Bedforth NM. Three-dimensional, multiplanar, ultrasound-guided, radial nerve block. Reg An Pain Med; in press Conflict of Interest:Dr Bedforth uses equipment provided by SonoSite Ltd, Hitchen, Hertfordshire, UK |
|||
|
|
|||
|
Belinda M Cornforth Royal Bournemouth Hospital, David M Hargreaves
Send letter to journal:
|
We read the recent editorial by Hopkins on ultrasound guidance for regional anaesthesia and would like to take issue with some of the comments and conclusions. While accepting that it is difficult to perform large scale, randomized studies in this area it is dangerous to draw such one sided opinions in the abscence of such studies. Medicine is littered with technologies which were introduced because logic indicated a benefit, but long term studies showed otherwise. Pulmonary artery catheters were one and in the field of obstetrics, which Hopkins uses as an example to further his argument, clinicians find themselves in a medico-legal minefield as a result of lack of clear evidence for some medical interventions.To imply that ultrasound should offer 100% success and 0% complications is optimistic in the extreme and to suggest that failure to meet these standards is down to 'operator deficiency' goes against one of the founding principles of risk management; we all err from perfection. Those of us who perform hundreds of regional blocks a year with a high success rate ( the 95% that Hopkins quotes)with no major complications, efficiently and with a minimum of equipment need good arguments for changing their established practice. We would not consider ourselves to be either intransigent or in the minority, as Hopkins would have us believe. We feel that ultrasound guidance will be a useful addition to the armamenterium of the anaesthetist practising regional anaesthesia, but to so strongly imply that those not using this method are medically negligent is a dangerous and unhelpful step. Conflict of Interest:None declared |
|||
|
|
|||
|
John A W Wildsmith, Professor of Anaesthesia University of Dundee
Send letter to journal:
|
Editor - Ultrasound guidance for regional anaesthesia is a very promising method, and there is much in the editorial from Hopkins that I agree with and support. However, the method must be investigated fully, not simply accepted as perfect as he proposes. Further, I would take issue with his third paragraph, one which I judge to be seriously incautious. To state, as he does, that a clinical aid will produce "successful nerve block with no complications" is wildy over-optimistic, but to then state that "any deviation from this standard is an operator deficiency" is an open invitation to the legal profession to pursue colleagues whose practice may otherwise be impeccable. Almost any method can be highly successful in the hands of an enthusiastic expert, but the true test is how well it works in routine use. Those who, like me, have been involved in regional anaesthesia for over three decades will remember that the introduction of nerve stimulators was supposed to eliminate block failure, but they did not, and the history of medicine as a whole is littered with the incautious introduction of 'advances' deemed too important for proper investigation, only for them to be shown, much later, to be less than advantageous. It is hard to see how the use of ultrasound could cause harm to patients, although it might engender excessive confidence and thus encourage incautious practice if not properly evaluated. Further, the equipment is expensive and justifying its cost will require the availability of high quality evidence. Enthusiastic reports after use in what are really very small numbers of patients (all that we have to date) do not represent such evidence. In regard to evidence I do not accept that randomised controlled trials have no place in the evaluation of ultrasound for regional anaesthesia, although I agree that the incidence of complications is (or should be) too low for such comparison. The same might be true of block succes rates, although I am not so sure, and properly designed and performed audit projects, albeit comprising hundreds of patients (large, but not unacheivable, especially on a collaborative basis), should be capable of generating hard data which can be compared with standard figures. Then, and only then, can ultrasound be put forward (not trumpeted) as a gold standard, assuming that the data warrant it! Conflict of Interest:None declared |
|||
|
|
|||
|
Andrew G Haldane, SHO Anaesthetics
Send letter to journal:
|
I read with interest P.M. Hopkins' thoughts on the subject of ultrasound guidance for regional anaesthesia. I particularly note his comments regarding the need for ultrasound techniques to become part of the core training of every anaesthetist. Many of us know consultants who have a wealth of experience in the field of regional anaesthesia; those individuals whose lists are eagerly sought out by trainees; an ideal opportunity to learn and practice new techniques. Imagine our frustration then to find said consultant wrestling with the shiny new ultrasound machine, half sure of what they are looking at and even less able to convince their eager trainee of what they are seeing. Each case followed by the promise "you can do the next one" - if only that were true. Conflict of Interest:None declared |
|||
|
|
|||
|
Colin JL McCartney, Assistant Professor Department of Anesthesia, University of Toronto
Send letter to journal:
|
As a proponent of ultrasound-guided regional anaesthesia I enjoyed reading the excellent case series by Drs. Karmakar, Kwok et al. However I have reservations about a number of the conclusions drawn in the accompanying editorial by Professor Hopkins. I agree that the recent regional anaesthesia ultrasound literature has many studies that lack equipoise. However this fact surely reinforces our responsibility to strive for the best quality ultrasound studies in order to properly answer the question of whether ultrasound techniques really do have significant advantages. This is because there are many existing and very successful users of other regional anaesthesia techniques that correctly demand the highest quality evidence before committing to the significant expense and inconvenience of training with new technology. Whilst I would agree with Professor Hopkins that almost all radiologists would support the use of ultrasound for certain interventional techniques this opinion has been developed through studies that exist in the radiology literature comparing ultrasound with other techniques for biopsy1-2. In addition radiology studies conclude that ultrasound is but one technique amongst many that can help achieve a predefined endpoint and that the optimal combination of a number of endpoints can improve success3. I also disagree that there are no inherent harmful effects of ultrasound- guidance. Many of the newly developed ultrasound-guided approaches have significant potential for harm if the needle tip is not carefully visualized and followed during insertion. Superficial ultrasound techniques often use very different needle insertion points compared to traditional techniques where the needle insertion point and path has been carefully developed to avoid vital structures4. If the needle tip is not clearly followed with ultrasound significant potential for mishap can occur. With deeper blocks local anaesthetic expansion can be difficult to appreciate using ultrasound and the usual precautions such as incremental injection and frequent aspiration remain very important. Inexperienced users of ultrasound can obtain a false sense of security and fail to continue to observe these precautions leading to potential for significant complications. Until we have further evidence for the benefit of ultrasound-guided regional anaesthesia in enhancing success and reducing complications it is premature to imply that ultrasound is a safer technique. We need to determine the ideal endpoint or combination of endpoints for different types of blocks. For many regional anaesthesia procedures I believe, based on personal experience and reading the literature, that ultrasound will be the key component. However until we have the best quality evidence to support this assumption we need to be very careful about making premature conclusions. References: 1. Frates MC, Benson CB, Charboneau JW et al. Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement. Radiology 2005; 237: 794-800. 2. Fajardo LL, Pisano ED, Caudry DJ et al. Radiologist Investigators of the Radiologic Diagnostic Oncology Group V. Stereotactic and sonographic large-core biopsy of nonpalpable breast lesions: results of the Radiologic Diagnostic Oncology Group V study. Acad Radiol 2004; 11: 293-308. 3. Dillon MF, Hill AD, Quinn CM, O'Doherty A, McDermott EW, O'Higgins N. The accuracy of ultrasound, stereotactic, and clinical core biopsies in the diagnosis of breast cancer, with an analysis of false-negative cases. Ann Surg 2005; 242: 701-7. 4. Brown DL, Cahill DR, Bridenbaugh LD. Supraclavicular nerve block: anatomic analysis of a method to prevent pneumothorax. Anesth Analg 1993; 76: 530-4. Conflict of Interest:Payment of honoraria by Sonosite Corporation. |
|||