Original Article

Bier’s block using prilocaine: safe, cheap and well tolerated

S.A.W. Pickering J.B. Hunter
Department of Trauma and Orthopaedic Surgery, University Hospital, Queen’s Medical Centre, Nottingham, NG7 2UH, U.K.
Correspondence to: S.A.W. Pickering, Department of Trauma and Orthopaedic Surgery, Queen’s Medical Centre, University Hospital, Nottingham, NG7 2UH, U.K. Email: simonpickering@tiscali.co.uk

Introduction Method Results

Discussion Conclusion References

Keywords: Colles, prilocaine, anaesthesia, local 
Surg J R Coll Surg Edinb Irel., 1 October 2003, 283-285

Objectives: To examine the safety of prilocaine Bier’s block performed for Colles fracture manipulation, and assess patient satisfaction. Method: Fifteen-year retrospective review of all patients undergoing Colles fracture manipulation with a prilocaine Bier’s block looking for the incidence of significant neurological or cardiovascular events. A confidential questionnaire was administered to 50 consecutive patients to assess patient satisfaction with the method of anaesthesia. Results: 1504 males with mean age 48 years and 5906 females with mean age 66 years received a prilocaine Bier’s block for distal radial fracture manipulation. There were no documented incidences of anaphylaxis, arrhythmia, convulsions or collapse. Of 50 consecutive patients, all but two were satisfied with this form of anaesthesia. The pressure cuff inflation was considered the worst part of the procedure. Conclusion: Bier’s block performed with prilocaine is at least as safe as other commonly used methods of anaesthesia for distal radial fracture reduction with high patient satisfaction. The procedure can be safely carried out by a single medical practitioner with appropriate patient monitoring and assistance from trained nursing staff

INTRODUCTION
Distal fracture of the radius is one of the most common orthopaedic injuries and fracture manipulation is often required before plaster application. General anaesthesia, intravenous sedation, haematoma block and intravenous regional block, so called Bier’s block, are four anaesthetic techniques available to achieve this. A questionnaire survey of 54 hospitals covered by CEPOD showed that 24 hospitals favoured a general anaesthetic on a day case basis, 18 hospitals favoured the Bier’s block and seven hospitals favoured some form of intravenous sedation, with or without analgesia.¹ Only four centres recommended haematoma block. There is still no consensus on the best technique to use.

Bier’s block is the method of regional analgesia where local anaesthetic is limited to the forearm by use of a pneumatic cuff. It is the most practical form of anaesthesia because it avoids unnecessary hospital admission and the use of valuable operating theatre time. However, as a result of the deaths of several patients in the early 1980s it fell out of favour.² A number of articles were published stating the dangers of this technique due to systemic toxicity of the local anaesthetic agents lignocaine and bupivicaine, should there be accidental tourniquet deflation.³ Consequently, many anaesthetists suggested that the technique should continue to be used only by them and in an operating theatre environment.⁴

At our centre, we provide acute orthopaedic services for a population of about 800,000. We continue to use the Bier’s block, as described by Wallace et al. (1982), to deal with the large numbers of patients with distal radial fractures requiring manipulation.⁵ Importantly, we use prilocaine rather than lignocaine or bupivicaine. In our retrospective study, we aimed to show the safety of prilocaine Bier’s block and its continued acceptability to patients.

METHOD
Patients had an intravenous cannula inserted into the back of the hand in the injured limb and into the uninjured hand or wrist. The injured limb was exsanguinated by elevation, before inflating a single cuff tourniquet to 100mmHg above the systolic blood pressure. Forty mLs of 0.5% prilocaine was injected into the injured limb and fracture manipulation carried out. Throughout the manipulation, the patients were monitored with a pulse oximeter. Patient cooperation was critical for successful fracture manipulation with continuous interaction between the surgeon and the patient. The tourniquet was kept inflated for 20 minutes following injection of the prilocaine.

All manipulations carried out under local anaesthesia at the Queen’s Medical Centre were recorded in an operation log book, which in addition to registration details, listed any particular problems with a given procedure, including adverse patient events. We reviewed the logbooks from 1985 (when use of prilocaine became the standard anaesthetic used for Bier’s block) to 2000 and made note of any adverse events. We made the assumption that any serious toxicity reaction to prilocaine would have occurred in the hour post-prilocaine administration. Patients would still have been in the fracture manipulation room at this point and any problems would have been documented.

We also administered a simple questionnaire to 50 consecutive patients asking them to choose whether the injections, the pressure cuff or the fracture manipulation was the worst part of the procedure. They were also asked to say how satisfied they were with the procedure, choosing to respond as extremely pleased, pleased, neither pleased nor upset, upset or extremely upset.

RESULTS
A total of 5906 females, with a mean age of 66 years, and 1504 males, with a mean age of 48 years, underwent manipulation of a distal radial fracture after Bier’s block. There were no documented incidences of anaphylaxis, arrhythmias, convulsions or collapse. Although patients were often admitted for social reasons, there were no documented admissions due to complications of the Bier’s block.

On analysis of the 50 questionnaires, 82% (41 patients) stated that the inflated pressure cuff was the worst aspect of the procedure, although the majority of this group stated that they were pleased or extremely pleased with the treatment (see Table 1). Twelve per cent (six patients) found the injections the worst aspect of the procedure and six per cent (three patients) found manipulation of the fracture to be the worst part of the procedure. In both groups, all of the patients were pleased or extremely pleased with their treatment.

DISCUSSION
Evidence-based medicine has become a core ideal for good practice. Not only is it important to evaluate any treatment or technique with regard to effectiveness and safety to patients, but also to consider the costs of a procedure for a health care system under increasing economic pressure.

There were legitimate concerns following the sudden death of previously fit and healthy patients during Bier’s block due to tourniquet failure and systemic toxicity of the injected anaesthetic agent. However, Heath et al. (1982) acknowledged that, although lignocaine and bupivicaine had significant toxicity, prilocaine had many safety advantages.³ The use of prilocaine is the critical factor. This drug has a much safer therapeutic index. Indeed, studies in rats have only shown EEG and ECG changes at 53mg/kg (concentration used in clinical practice is <10mg/kg).⁶ There are no reports of sudden death related to the use of this local anaesthetic agent, although there were two reported cases of local hypersensitivity reactions during prilocaine injection and several references to methaemoglobinaemia in neonates after use of EMLA cream that contains a mixture of prilocaine and lignocaine.

General anaesthesia, although a popular choice for Colles fracture manipulation, has risks that correlate with the premorbid health of patients. Bearing in mind that the majority of patients requiring distal fracture manipulation are elderly, it would be unwise to propose a general anaesthetic as being the safest way to routinely manage displaced Colles fractures. At a busy centre, many patients may present each day with displaced Colles fractures and even in large units, operating theatre capacity is inadequate to cope with the demand.

Funk (1997) carried out a prospective trial with 58 adults requiring distal radial fracture manipulation, comparing general anaesthsia haematoma block with sedation.⁷ The resource costs and waiting times to treatment were much higher with general anaesthetic cases, although there were no major complications. The most cost effective outcome was achieved with a haematoma block and sedation.

Haematoma block has been compared directly with Bier’s block.

Although there were comparable outcomes for fracture management, patients found haematoma block to be a painful procedure.⁸ Quinton (1988) showed that potentially toxic levels of lignocaine were reached after injection of 10mLs 1% lignocaine into a fracture haematoma.⁹ Kongsholm and Olerud (1987) showed a significantly higher incidence of neurological complications in radial fractures treated this way.¹⁰

Intravenous sedation also has many potential risks. In young fit patients, Zacharias et al. (1992) noted a transient fall in oxygen saturation with midazolam, and others have noted cardiac dysrrhythmias with this type of sedation.¹¹ Again, these side effects will be higher in elderly patients who have health problems.

It is our perception that many centres dealing with trauma are dismissing the Bier’s block as a dangerous form of anaesthesia for treating Colles fractures, due to their misinterpretation of the available evidence and preformed prejudices. There may be a case for concern with lignocaine and bupivicaine, but certainly not with prilocaine.

Our retrospective audit of Bier’s block in adults using prilocaine presents good evidence showing it to be at least as safe, when compared with other routinely used anaesthetic techniques used for Colles fracture manipulation, with no recorded major complications such as neurological or cardiovascular collapse. Large numbers have been performed by a single trained SHO working with experienced nursing staff from fracture clinic, combined with appropriate patient monitoring. The procedure is not time consuming, is cheap and allows patients to be dealt with swiftly without the need for prolonged monitoring or inpatient stay.

Our Colles fracture results are consistent with those throughout the country, and patients clearly find a Bier’s block to be an acceptable form of anaesthesia with the majority of patients being pleased or extremely pleased following its use. The worst part of the procedure was the pressure cuff. As with any questionnaire study of this type, there is inevitably a degree of bias towards high patient satisfaction. Most patients are naturally relieved at the end of a procedure and will tend to give a favourable feedback. However, if patients had found this anaesthetic technique to be genuinely traumatic we would have expected this to have been reflected in our results.

CONCLUSION
Bier’s block is at least as safe as other anaesthetic techniques used to enable Colles fracture manipulation in adults. In a busy department it allows large numbers of patients to be dealt with swiftly by a single, appropriately trained SHO and trained nurse. Patient satisfaction remains high, results of reduction are good and the procedure is inexpensive.

REFERENCES
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3. Heath ML. Deaths after intravenous regional anaesthesia. BMJ 1982;285: 913-4.
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5. Wallace A, Guardini R, Ellis S. Standard intravenous regional analgesia. BMJ 1982;285:654-6.
6. Rosenberg PH, Zou J, Heavner JE. Comparison of acute central nervous system and cardiovascular toxicity of 2-chloroprocaine and prilocaine in the rat. Acta Anaesthesiologica Scandinavica 1993;37 (8):751-5.
7. Funk L. A prospective trial to compare three anaesthetic techniques used for the reduction of fractures of the distal radius. Injury 1997;28(3):209-12.
8. Cobb AG, Houghton GR. Local anaesthetic infiltrtation versus Bier’s block for Colles fractures. BMJ 1985;291:1683-4.
9. Quinton DN. Local anaesthetic toxixity of haematoma blocks in manipulation of Colles fractures. Injury 1988;19(4):239-40.
10. Kongsholm J, Olerud C. Neurological complications of dynamic reduction of Colles fractures without anaesthesia compared with traditional manipulation after local anaesthetic infiltration anaesthesia. J Orth Trauma 1987;1(1): 43-7.
11. Zacharias M, Luyk NH, Parkinson RT. Oxygen saturation during intravenous sedation using midazolam. N Z Dent J 1992;94-6.

Copyright: 19 August 2003