Ultrasound guidance as a gold standard in regional anaesthesiaIt is now just over 2 yr since Marhofer and colleagues,[url=http://bja.oxfordjournals.org/cgi/content/full/98/3/299#AEL387C1]1 in this journal, reviewed the use of ultrasound in regional anaesthesia. They concluded with the hope that the availability of portable ultrasound systems with high-frequency probes would promote the routine use of ultrasound guidance in regional anaesthesia. This review, however, was accompanied by an editorial that queried the evidence base for preferring ultrasound guidance to other techniques of nerve localization.2 With the widespread availability to anaesthetists of high-resolution portable ultrasound machines,3 it is timely to consider if sufficient evidence has accumulated to quell the doubts expressed by Denny and Harrop-Griffiths.2 Denny and Harrop-Griffiths2 pointed out the difficulties in proving increased success rates in comparison with those of experienced regional anaesthetists and emphasized the paucity of data concerning improvements in safety in the context of procedures with low baseline rates of complications. Having excluded studies lacking equipoise (comparisons between ultrasound and suboptimal ‘standard’ techniques), I was only able to find one study in the past 2 yr, by Willschke and colleagues,4 which demonstrated an improved success rate using ultrasound guidance for any regional anaesthetic technique: in this case, ilioinguinal and iliohypogastric nerve blocks in children. The same group also demonstrated a reduction in misdirection of the needle during epidural catheter insertion in children when comparing ultrasound guidance with a loss-of-resistance technique.5 There are, however, several papers describing how the availability of ultrasound enables new techniques with great promise to be attempted.6–8 So, is the status of ultrasound guidance in regional anaesthesia to be paralysed by an inability to satisfy the lust for the highest levels of ‘evidence-based medicine’? My personal view is that ultrasound guidance is such a significant step-change in regional anaesthesia, with no inherent harmful effects, that there can be no valid comparative study with ‘traditional’ techniques that will produce results generally applicable to other anaesthetists. This is because, 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. In other words, any deviation from this standard is an operator deficiency rather than a short-coming of the technique. The situation is quite different with other regional anaesthetic techniques, for example using nerve stimulation. Aside from situations when nerve stimulators cannot be used,9 the nerve stimulator can only confirm that the needle tip is in the location that the operator thinks it is, and then with only modest sensitivity10 and incomplete specificity, which is why even in the best hands success rates peak at around 95%.2 Of course, a nerve stimulator is no help in avoiding puncture of blood vessels, the pleura, and other vulnerable structures, the anatomical relations of which to the target nerves show considerable variability.1112 Such variability becomes readily apparent to those who regularly block the femoral nerve under ultrasound guidance. At the level of the groin skin crease the femoral artery may or may not have given off its major branch, the profunda femoris artery: the posterior division of the femoral nerve can lie posterior or lateral to the femoral artery and occasionally will be seen between the femoral and profunda femoris arteries. Furthermore, the lateral circumflex femoral artery, which usually arises from the profunda femoris but sometimes the femoral artery, can occasionally be seen just distal to the groin skin crease passing between the divisions of the femoral nerve. Similarly, I have occasionally identified branches of the subclavian artery (superficial cervical or supra-scapular branches11) passing between divisions of the brachial plexus in the supraclavicular fossa. Incidental to the success of the block and avoidance of complications, no regional technique other than ultrasound guidance can be used to diagnose unrelated conditions such as deep venous thrombosis.13 I would argue, therefore, that it is irrelevant to demand randomized clinical trials comparing ultrasound guidance with other regional anaesthetic techniques. After all, I suspect that several thousand radiologists might disagree with the contention that there is insufficient evidence that needles can be positioned more accurately and safely under ultrasound guidance than without imaging. As anaesthetists, in the contexts of both regional anaesthesia and vascular access, we are perhaps going through a similar process to that already navigated by obstetricians and cardiologists. I can remember, for example, obstetricians saying that they did not need an ultrasound scan to know that a pregnancy was progressing normally with a healthy foetus at 16 weeks gestation. They were probably correct much more than 95% of the time, but now it would be considered negligent not to offer a scan. I believe this is the direction we are heading in with regional anaesthesia, the speed of travel potentially rapid with some blocks, such as brachial plexus and femoral nerve blocks, but more circumspect with others such as epidurals and spinals. In other words, ultrasound guidance for regional anaesthesia is the gold standard technique we should be striving to adopt. It is relatively easy to acknowledge that ultrasound guidance should be used, but there are significant obstacles to implementation. Surprisingly, availability of equipment, at least in the UK, is perhaps the least of these. A current but temporary problem is the intransigence of a minority of experienced regional anaesthetists who, having spent many years developing their expertise with one technique, face learning a new one. My advice, based on 13 yr of consultant practice using brachial plexus blocks without ultrasound (96% success in terms of suitability for surgery), is that the change to ultrasound guidance is entirely positive, albeit a little frustrating at times along the way. This leads onto the biggest challenge—training. Bodenham has comprehensively detailed the issues that need to be tackled when considering training of anaesthetists in the use of ultrasound.14 For regional anaesthetists, the development is probably as significant as the introduction of laparoscopic surgery for general surgeons almost 20 yr ago. As Bodenham suggests,14 the majority of senior colleagues will learn from their peers, but training in ultrasound techniques needs rapidly to become part of the core training of every anaesthetist, just as laparoscopic work is for surgeons. In the meantime, careful consideration will be needed when consenting patients for regional anaesthetic techniques. Some of my ‘regular’ patients with rheumatoid arthritis are already asking to have ‘the block with the scanner’ rather than the ‘twitcher’ and, considering the number of patients who research their medical treatment on the internet, I think it is only a matter of time before a patient asks me whether I will be using ultrasound and what my experience with it is. It behoves all practitioners, therefore, to be explicit in describing their own experience with any proposed regional anaesthetic technique. Furthermore, I believe we will soon be at the stage, for example with brachial plexus blocks, when it is advisable to inform the patient of the potential benefits of an ultrasound guided technique even when this cannot be offered to them (perhaps because of inexperience on the part of the anaesthetist or lack of suitable equipment). This will be needed to counter the argument, in the event of litigation arising from a complication, that the patient would not have consented if they had known a potentially safer technique was available elsewhere. Finally, I would not like to give the impression that research and development is not necessary in the field of ultrasound-guided regional anaesthesia. Much can be done in terms of optimizing ultrasound-guided techniques,6–815 describing the frequency of relevant anatomical variants and defining minimum effective doses of local anaesthetic for different blocks when applied accurately under ultrasound guidance.16 In the longer term, we should look forward to studies of ‘real-time’ 3D ultrasound imaging and robotically assisted ultrasound-guided needle placement.17 [size=+1]Declaration of interest The author has used ultrasound equipment loaned by SonoSite UK Ltd and has received funding from SonoSite UK Ltd for expenses relating to speaking engagements. P. M. Hopkins Academic Unit of Anaesthesia St James' University Hospital Leeds LS9 7TF UK E-mail: [email protected]
References1 Marhofer P, Greher M, Kapral S. (2005) Ultrasound guidance in regional anaesthesia. Br J Anaesth94:7–17.[Abstract/Free Full Text] 2 Denny NM and Harrop-Griffiths W. (2005) Location, location, location! Ultrasound imaging in regional anaesthesia. Br J Anaesth94:1–3.[Free Full Text] 3 McGregor M, Rashid A, Sable N, Kurian J. (2006) Impact of NICE guidance on the provision of ultrasound machines for central venous catheterization. Br J Anaesth97:117–8.[Free Full Text] 4 Willschke H, Marhofer P, Bosenberg A, et al. (2005) Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children. Br J Anaesth95:226–30.[Abstract/Free Full Text] 5 Willschke H, Marhofer P, Bosenberg A, et al. (2006) Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique. Br J Anaesth97:200–7.[Abstract/Free Full Text] 6 Willschke H, Bosenberg A, Marhofer P, et al. (2006) Ultrasonography-guided rectus sheath block in paediatric anaesthesia – a new approach to an old technique. Br J Anaesth97:244–9.[Abstract/Free Full Text] 7 Eichenberger U, Greher M, Kirchmair L, Curatolo M, Moriggl B. (2006) Ultrasound-guided blocks of the ilioinguinal and iliohypogastric nerve: accuracy of a selective new technique confirmed by anatomical dissection. Br J Anaesth97:238–43.[Abstract/Free Full Text] 8 Lundblad M, Kapral S, Marhofer P, Lonnqvist PA. (2006) Ultrasound-guided infrapatellar nerve block in human volunteers: description of a novel technique. Br J Anaesth97:710–4.[Abstract/Free Full Text] 9 Plunkett AR, Brown DS, Rogers JM, Buckenmaier CC. (2006) Supraclavicular continuous peripheral nerve block in a wounded soldier: when ultrasound is the only option. Br J Anaesth 3rd 97:715–7.[Abstract/Free Full Text] 10 Perlas A, Niazi A, McCartney C, Chan V, Xu D, Abbas S. (2006) The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound. Reg Anesth Pain Med31:445–50.[CrossRef][ISI][Medline] 11 Cach CJ, Sardesai AM, Berman LH, et al. (2005) Spatial mapping of the brachial plexus using three-dimensional ultrasound. Br J Radiol78:1086–94.[Abstract/Free Full Text] 12 Royse CE, Sha S, Soeding PF, Royse AG. (2006) Anatomical study of the brachial plexus using surface ultrasound. Anaesth Intensive Care34:203–10.[ISI][Medline] 13 Sutin KM, Schneider C, Sandhu NS, Capan LM. (2005) Deep venous thrombosis revealed during ultrasound-guided femoral nerve block. Br J Anaesth94:247–8.[Abstract/Free Full Text] 14 Bodenham AR. (2006) Ultrasound imaging by anaesthetists: training and accreditation issues. Br J Anaesth96:414–17.[Free Full Text] 15 Bigeleisen P and Wilson M. (2006) A comparison of two techniques for ultrasound guided infraclavicular block. Br J Anaesth96:502–7.[Abstract/Free Full Text] 16 Willschke H, Bosenberg A, Marhofer P, et al. (2006) Ultrasonographic-guided ilioinguinal/iliohypogastric nerve block in pediatric anesthesia: what is the optimal volume? Anesth Analg102:1680–4.[Abstract/Free Full Text] 17 Kettenbach J, Kronreif G, Figl M, et al. (2005) Robot-assisted biopsy using ultrasound guidance: initial results from in vitro tests. Eur Radiol15:765–71.[CrossRef][ISI][Medline]
[size=-1]M. S. Abrahams, M. F. Aziz, R. F. Fu, and J.-L. Horn Ultrasound guidance compared with electrical neurostimulation for peripheral nerve block: a systematic review and meta-analysis of randomized controlled trials
Br. J. Anaesth., March 1, 2009; 102(3): 408 - 417. [Abstract][Full Text][PDF]
[size=-1]L. T. Newsome, R. S. Weller, J. C. Gerancher, M. A. Kutcher, and R. L. Royster Coronary Artery Stents: II. Perioperative Considerations and Management
Anesth. Analg., August 1, 2008; 107(2): 570 - 590. [Abstract][Full Text][PDF]
[size=-1]L. A. Colvin and A. M. Moller Volume 100: clinical investigations: where next?
Br. J. Anaesth., April 1, 2008; 100(4): 433 - 435. [Full Text][PDF]
[size=-1]C. J. L. McCartney, J. A. W. Wildsmith, B. M. Cornforth, D. M. Hargreaves, C. van Velzen, and P. M. Hopkins Ultrasound guidance for regional anaesthesia.
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Ultrasound-Guided Regional Anaesthesia: Possibly Gold But Not Yet Standard Colin JL McCartney British Journal of Anaesthesia, 13 Mar 2007 [size=-1][Full text] Ultrasound guidance is not yet the gold standard in regional anaesthesia. John A W Wildsmith British Journal of Anaesthesia, 15 Mar 2007 [size=-1][Full text] Frustration with Ultrasound Guidance Andrew G Haldane British Journal of Anaesthesia, 15 Mar 2007 [size=-1][Full text]Ultrasound Guidance: a Response Belinda M Cornforth, et al. British Journal of Anaesthesia, 30 Mar 2007 [size=-1][Full text] Re: Ultrasound guidance as a gold standard in regional anaesthesia Nigel M Bedforth, et al. British Journal of Anaesthesia, 30 Mar 2007 [size=-1][Full text] Some remarks on the editorial of P.M. Hopkins in BJA march 2007 Chris van Velzen British Journal of Anaesthesia, 30 Mar 2007 [size=-1][Full text] Guided or Blinded Hui Yun Vivian Ip British Journal of Anaesthesia, 22 Apr 2007 [size=-1][Full text] Author's response Philip M Hopkins British Journal of Anaesthesia, 1 May 2007 [size=-1][Full text]
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