Department of Anaesthetics, The Royal Infirmary of Edinburgh, Edinburgh EH16 4SU1, UK E-mail: david.scott{at}ed.ac.uk
The advantages of ultrasound guidance (USG) for central venous catheterization (CVC) have previously been extolled in the pages of this journal.13 They include a greater likelihood of success, fewer complications and less time spent on the procedure. It is even possible that money may be saved in the process. There was considerable debate in the medical literature, on the Internet and at meetings around the country when the National Institute for Clinical Excellence (NICE) produced its recommendations:4
Two-dimensional (2-D) imaging ultrasound guidance is recommended as the preferred method for insertion of central venous catheters (CVCs) into the internal jugular vein (IJV) in adults and children in elective situations.
The use of two-dimensional (2-D) imaging ultrasound guidance should be considered in most clinical circumstances where CVC insertion is necessary either electively or in an emergency situation.
An editorial in the British Medical Journal5 recommended ultrasound for difficult cases only. One opponent of the guidelines6 wrote NICE have taken a sledgehammer to crack a nut. A large series7 from the University of Pennsylvania, the birthplace of the dedicated USG scanner, reported that the expected reduction in carotid punctures using USG did not materialize. At a debate organized by the Association of Anaesthetists of Great Britain and Ireland, the first NICE recommendation was rejected by almost 10 times the number who supported it. But the quiet majority now seem to support the guidelines, and the debate is worthy of further analysis.
Muhm's editorial5 opens with the heading It is useful for beginners, in children, and when blind cannulation fails, and concludes Ultrasound assistance is a potential useful back up technique after failed attempts of blind cannulation, and for patients in whom catheterisation is likely to be difficult and complications could be serious. Nine per cent of patients have abnormalities of the anatomy of their central veins that make catheterization difficult, dangerous or impossible.8 Most of them appear normal on superficial inspection. The advocates of ultrasound believe that it is far better to use ultrasound routinely from the outset, detect the abnormality, and prevent a difficult case becoming a problem case. Watters summarized this philosophy succinctly:9 Why only use a technology when things might be difficult, or when you have failed without it? I wear my seatbelt every time I drive my car, not just when the road looks a bit dangerous, or when I've just had a near miss. He uses a very appropriate example. There was an outcry when wearing seatbelts was made compulsory. Their adoption was a major advance in road safety, with which few would now argue.
Hyashi and Amano10 showed that detecting venous pulsation with respiration was a good predictor of easy CVC in their group of 240 patients. When this sign was present, they had few difficulties with CVC, and they perceived no benefit from the use of ultrasound. The sign was only visible in 78.3% of patients, however, and in the rest ultrasound was far superior. The access rate at first attempt was 30% using landmarks and 86% with ultrasound, success rate 78 vs 100%, and carotid puncture rate 13% vs none. These results are highly significant. The authors concluded that the prepuncture use of ultrasound guidance is not routinely needed when the respiratory jugular venodilation can be used as a landmark for puncture. They did endorse ultrasound for those cases where the sign was not present. My experience of trying to teach this sign, and the similar technique of balloting the vein, is that the average trainee is not attached to me for long enough to learn it, but quickly picks up the use of ultrasound. As the scanner has to be available for those cases where respiratory jugular venodilation is not present, is it not better to use it from the start rather than spend time looking for a sign that is absent in 20% of patients?
Augoustides and colleagues7 studied 462 procedures in the cardiothoracic service in the University of Pennsylvania Hospital, the cradle of the SiteRite. They said that they found no statistically significant reduction in carotid puncture rates with the use of USG CVC. Their crude figures were 8.1% with landmark and 5.8% with ultrasound, but the groups they used were not comparable. They quoted the clinical level of training of the operators. First-year trainees performed 92 USG CVCs with seven punctures, but only 14 landmark catheterizations, with no punctures. It does not seem appropriate to include their results. The attending physicians, presumably skilled in the old techniques, did badly: 5/17 carotid punctures with ultrasound and 0/17 with landmark. Perhaps this was their learning curve, or they were only using USG for patients that they perceived would be difficult, as the choice of technique was left to the operator. The carotid puncture rates for intermediate trainees and the fellows were vastly improved by the use of ultrasound: 17/728 (2.3%) with ultrasound and 8/57 (14%) with landmark. This is highly statistically significant. This result strongly favours the use of ultrasound by intermediate trainees and fellows, and perhaps indicates that the attending physicians need a bit more practice with ultrasound.
The risk of death from central venous catheterization, while finite,1114 is low. It is unlikely that any randomized, double-blind trials of USGCVC using mortality as an end point will be attempted, as the numbers that would have to be enrolled are vast. Newland and colleagues,13 from the University of Nebraska Hospital, reported on 72 959 anaesthetics over a 10-yr period. Attempts at central venous catheterization were responsible for 20% of the anaesthesia-related cardiac arrests in their study. The actual number of deaths, however, was only two. Calculating the mortality rate for CVC in this series, is not possible, as the denominator (the number of attempts at central venous catheterization) is unknown. The National Confidential Enquiry into Perioperative Deaths investigation of Interventional Radiology12 did provide a denominator. Thirty-five patients died after 3052 cannulations, but most of these patients died from progression of their disease, usually malignant, and only one of the deaths, from a pneumothorax, was considered to be due to the procedure itself. It is difficult to ascribe statistical significance to one event, and it would be wrong to use this paper as support for the mortality from CVC being 3 per 10 000. Similarly, the rate of serious complications is unknown. Reuber and colleagues14 reviewed the records of the Yorkshire neurology and vascular surgery units between March and September 1999. In the 6-month period, they found four patients with disabling strokes after attempted CVC. One patient died. One of the non-fatal strokes followed carotid puncture with the seeking needle only. They recommended the use of ultrasound to reduce the risk of arterial injury.
David, later king of Israel, demonstrated an important lesson in weapons technology15 when he used a long-range ballistic missile to conquer Goliath, the champion of the Philistines and a formidable warrior at close range. David got ahead with technology, and Goliath lost his head. A major contribution to the success of the Unionist forces in the American civil war was the possession of more Springfield rifles,16 accurate at 400 yards, four times the distance that the Confederate muskets could reliably hit their mark. No wonder the Unionists won the war!
Double-blind trials are not usual in the armaments industry. Superior technology usually produces a winner and a loser at the first experiment, and the loser is reluctant to repeat the contest. The tyre that John Dunlop invented to enable his son's tricycle to cope with the bumpy pavements of Belfast17 was adopted by racing cyclists. When indifferent cyclists riding bikes with Dunlop tyres started to win the races, everyone who wanted to win started to use them. (I am constantly reminded of the benefits of pneumatic tyres when I walk the corridors of my new hospital. Patients are shaken as their trolleys, with solid rubber tyres, bounce up and down over the holes in the linoleum produced by the even more solid metal wheels of the goods delivery trolleys.) In 1956, the world of motor racing was astonished when the Le Mans 24 h race was won by two unknown Scotsmen driving a D-Type Jaguar that had been prepared in a back-street garage in Edinburgh.18 Showing that it was no fluke, the Ecurie Ecosse team returned the next year, this time with two cars. Coming first and second, beating all, including the works Jaguar team, they established the reputation of their secret weapon, disc brakes. When Jaguar fitted disc brakes to their own cars, Ecurie Ecosse's domination of the race ended. Disc brakes have proved their worth without double-blind, randomized trials, and are now found even on cheap family cars. The pneumatic tyre and the disc brake swept the world by being associated with winners. Do we need to mount more expensive trials, as NICE4 encourages us to do, just to persuade a few Luddite losers to enter the 21st century? I think not. Within a few years they will have retired, to be replaced by a new generation of anaesthetists, no more likely to attempt central venous cannulation without ultrasound guidance than they would be to embark on an anaesthetic without an ECG, a pulse oximeter and capnograph.
This issue of the British Journal of Anaesthesia contains two papers demonstrating that the use of ultrasound guidance for CVC is spreading from its original home, the internal jugular vein. Sharma and colleagues19 describe remarkable success with the ultrasound-guided equivalent of subclavian vein catheterization. The standard approach to the subclavian vein, close to the lower border of the clavicle, does not work with ultrasound, as the clavicle gets in the way of the ultrasound beam. The vein is easy to detect with a slightly more lateral approach, and the whole process of cannulation proceeds in a similar way to that of internal jugular vein cannulation. Their 200 cases had a success rate of 96% and an arterial puncture rate of 1.5%, and two patients suffered transient neuralgia. For many years, I have been using this technique and describing it in my patients' notes as subclavian vein cannulation. The authors, however, use the anatomically correct term axillary vein cannulation. Anatomists say that the axillary vein ends at the border of the first rib, where it becomes the subclavian vein.20 I do not feel the need to obtain my patients' notes and change the description of the procedure from subclavian to axillary, as my cannulae were only in the axillary vein for a centimetre or two, but travelled the whole length of the subclavian vein. In fact I have some concern that calling this procedure axillary vein catheterization may cause confusion. It is should be easy to catheterize the axillary vein using a transaxillary approach, so the two approaches to the vein have to be distinguished. Rather than use the terms transaxillary, axillary vein cannulation' and infraclavicular axillary vein cannulation, I think that I will stick with subclavian vein cannulation using ultrasound. Whatever name is given to the technique, however, it works well.
Sandhu and Sidhu21 describe the usefulness of ultrasound in attempting to secure venous access when all the visible superficial veins have been thrombosed, scarred or obscured by drug abuse, medical therapy or obesity. They detail four examples of over 120 cases. Again, the technique works exceedingly well. While my practice makes central venous cannulation an easy option when even the medial vein of the big toe is unavailable, we have frequently had grateful patients and phlebotomists, thankful that ultrasound has abolished the acupuncture that used to accompany the morning blood round. What the Tricky Vein Society will make of this I do not know. Will Sandhu and Sidhu be made honorary members for simplifying the procedure, or be banned sine die for removing the Society's raison d'etre?
Despite the few vocal opponents of USG for CVC, the silent majority are showing interest in the topic. Workshops on the subject at the last three anaesthetic updates run by DOCTORSUPDATES.COM have been oversubscribed, and additional workshops have been put on at the last minute. Many of those who attended had acquired the technology, and wanted instruction, so that they could use it on their patients. I hope that they have already done so, because the Department of Health have just circulated a letter, NHS HDL (2004) 04,22 saying This letter advises that clinicians planning to undertake new interventional procedures (see definition in paragraph 17) should seek approval from their organization's Clinical Governance Committee before doing so. Paragraph 17 reads An interventional procedure is one used for diagnosis or treatment that involves incision, puncture, entry into a body cavity, electromagnetic energy or ultrasound. An interventional procedure should be considered new if a doctor no longer in a training post is using it for the first time in his or her NHS clinical practice. This memo, designed no doubt to stop surgeons using untried and untested technology, places an extra hurdle in front of those wishing to improve their clinical practice by following the NICE guidelines.
Ultrasound guidance for venous and arterial catheterization is here to stay. Its use is spreading over the medical world, and over many sites on patients. Its advantages were emphasized by Alasdair Waite at the Edinburgh and East of Scotland Society of Anaesthetists Members' Night. His presentation of poetry (published with permission) included:
Our Masters at NICE have all spoken,The SiteRite is not just a token,
To look with one eye,
Is better than try,
And end up with carotids all broken.
References
1 Scott DHT. In the country of the blind, the one-eyed man is king. Erasmus (14661356). Br J Anaesth 1999; 82: 8201
2 Hatfield A, Bodenham A. Portable ultrasound for difficult central venous access Br J Anaesth 1999; 82: 8226
3 Scott DHT. It's NICE to see in the dark. [Editorial]. Br J Anaesth. 2003: 90: 26972
4 Calvert N, Hind D, McWilliams RG, Thomas SM, Beverley C. The effectiveness and cost effectiveness of ultrasound locating devices for central venous access. National Institute for Clinical Excellence, 2002. http://www.nice.org.uk/Docref.asp?d=3019
5 Muhm M. Ultrasound guided central venous access. BMJ 2002; 325: 13734
6 Chalmers N. Nice should reconsider its guidance on the use of ultrasound for placing central venous catheters. BMJ.COM, 2002. http://bmj.com/cgi/eletters/325/7377/1373
7 Augoustides JG, Diaz D, Weiner J, Clarke C, Jobes DR. Current practice of internal jugular venous cannulation in a university anesthesia department: influence of operator experience on success of cannulation and arterial injury. J Cardiothorac Vasc Anesth 2002; 16: 6771
8 Denys BG, Uretsky BF. Anatomical variations of internal jugular vein location: impact on central venous access. Crit Care Med 1991; 19: 15169[ISI][Medline]
9 Watters MP. Where is the harm in using ultrasound guidance? BMJ.COM, 2002. http://bmj.com/cgi/eletters/325/7377/1373
10 Hyashi H, Amano M. Does ultrasound imaging before puncture facilitate internal jugular vein cannulation? Prospective randomised comparison with landmark-guided puncture in ventilated patients. J Cardiothorac Vasc Anesth 2002; 16: 5725[CrossRef][ISI][Medline]
11 Booth SA, Norton B, Mulvey DA. Central venous catheterization and fatal cardiac tamponade. Br J Anaesth 2001; 87: 298302
12 Interventional vascular radiology and interventional neurovascular radiology. National Confidential Enquiry into Perioperative Deaths, 2000. http://www.ncepod.org.uk/20003.htm
13 Newland MC, Ellis SJ, Lidiatt CA, et al. Anesthetic-related cardiac arrest and its mortality. Anesthesiology 2002; 97: 10815[ISI][Medline]
14 Reuber M, Dunkley LA, Turton EPL, Bell MDD, Bamford JM. Stroke after internal jugular venous cannulation. Acta Neurol Scand 2002: 105: 2359[CrossRef][ISI][Medline]
15 Holy Bible, King James version, 1 Samuel 17: 50
16 Weapons of the American Civil War. http://www.civilwarhome.com/weapons.htm
17 Microsoft Encarta Encyclopaedia Delux, 2000. John Boyd Dunlop
18 Classic Driver Magazine. Ecurie Ecosse on track for a return to Le Mans. http://www.classicdriver.com/uk/magazine/3300.asp?id+11518
19 Sharma A, Bodenham AR, Mallick A. Ultrasound guided axillary vein cannulation for central venous access. Br J Anaesth 2004; 93: 188192
20 Jamieson EB. A Companion to Manuals of Practical Anatomy, 4th edn. London: Oxford University Press, reprinted 1965; 444
21 Sandhu NS, Sidhu DS. Mid arm approach to basilic and cephalic vein cannulation using ultrasound guidance. Br J Anaesth 2004; 93: 2924
22 Scottish Executive Health Department, NHS HDL (2004) 04: http://www.show.scot.nhs.uk/sehd/mels/HDL2004_04.pdf