A 12-year-old healthy male fell while learning how to use his hoverboard. An X-ray done in the ER shows a displaced distal radius fracture, amenable to reduction and non-surgical management. While discussing the reduction technique, his parents request analgesia with as little sedation as possible because they don’t want him “put to sleep.”
You recall reading about a type of regional anaesthesia for the upper extremities but do not know the effectiveness and the risks associated with it.
Boring Question: Is the Bier Block (BB) an effective and safe method to perform distal upper extremity procedures in the ED?
What is a Bier Block?
The BB is a regional anaesthesia technique used for procedures of the extremities, first documented by surgeon August Bier in 1908. An IV is placed in the affected limb and the limb is elevated promoting exsanguination. Next, a double lumen blood pressure cuff is placed proximal to the fracture, the proximal lumen is then inflated to 50-100 mmHg above the resting systolic resting BP. The procedure requires infusion of diluted lidocaine in an IV distal to the inflated tourniquet. The dose of lidocaine is 3mg/kg of 1% lidocaine in adults and in children diluted 1:1 to create a 0.5% lidocaine solution. The diluted lidocaine is injected into the affected limb injected at a rate of 20mL/min. Within 15 minutes, the limb is anesthetised allowing manipulation of the fracture. After the procedure is performed the lumen is gradually released to avoid systemic toxicity.1
A free Bier Block app available on iPhone has background information about the BB including videos, a calculator for appropriate dosing, and a timer for performing the procedure safely. The app (which can be retrieved here) includes all the protocols and guidelines used at the Montreal Children’s Hospital ED.
Patient selection is a key aspect of BB success. Children and adults with significant anxiety, unable to verbalize if experiencing symptoms of overdose (metallic taste in mouth or ringing in ears), or unable to tolerate tourniquet discomfort or procedures that will last more than 60-90 minutes are inappropriate for the BB technique, however most procedures do not last more than 30-60 minutes.1 The benefits of the Bier block include: rapid recovery time, fast and reliable onset of anaesthesia, a low failure rate, simple technical requirements (ability to perform a venipuncture) and the procedure can be performed regardless of fasting status. The procedure is contraindicated in patients with Raynaud’s disease, those with crush injuries, and those with homozygous sickle cell disease. The mechanism of action is controversial, but it is believed that it is a two-step mechanism involving an initial binding of anaesthetic to local nerve endings inhibiting the transmission of nerve impulses and later a blockade of nerve tracts as the anaesthesia penetrates from superficial to deeper veins.1
Are Bier Blocks effective?
A study comparing BB to procedural sedation while reducing forearm fractures in the pediatric population demonstrated a shorter procedure duration for the BB (47 minutes) vs the procedural sedation (102 minutes) and a lower associated cost for BB ($4 956USD) vs. procedural sedation ($ 6 313USD). No serious complications such as life-threatening cardiac, respiratory or epileptic events were noted in any of the 600 patients who underwent BB and 645 that underwent procedural sedation.2
A retrospective study including 1816 patients (pediatric portion unspecified) undergoing BB for forearm injuries (wrist injuries being the most frequent) resulted in 9 adverse events, none resulting in serious morbidity or mortality. This study was performed at an outpatient facility without any surgical or in-patient bed resources. BB was shown to be an “extremely safe and effective technique for the management of forearm injuries by primary care physicians.” 3 In addition to the reduction of fractures and dislocations, the procedure can be used for draining of abscesses, burn debridement, and foreign body extraction.3
A more recent study, accepted for publication in Pediatric Emergency Care, compared the BBs to procedural sedation with ketamine at a tertiary pediatric referral center with all procedures performed in the ED.4 Nursing staff and physicians at this institution were all provided with training in using the BB. PED staff completed a pre-course self-directed web-based learning module prior to attendance of a complementary simulation-based training session. A half-day course, including 30 minutes of didactic teaching were given to participants at the simulation centre to complete the training.5
The study, which included 109 patients undergoing BB and 165 undergoing procedural sedation, demonstrated that the mean length of stay for BB patients was 82 minutes shorter compared to procedural sedation.4 No differences between reduction success and return visit rates occurred between groups. BB patients suffered less minor adverse events compared to the procedural sedation group.
What are the risks associated with a Bier Block?
A review of studies between 1964 and 2000 yielded 64 instances where serious complications in the ED setting occurred with the Bier block.6 Major complications included 10 patients with compartment syndrome, 24 cases of seizures, and 13 cases of cardiac arrests. These complications were due to incorrect use of hypertonic saline in flushing the IV catheter, incorrectly prepared solutions, excessively long periods of tourniquet inflation, and doses of lidocaine higher than or equal to 2.5 mg/kg.
Additionally, the use of bupivacaine was associated with death in 7 patients and isolated cases of edema of the upper extremity. It binds irreversibly to the myocardium. It is, therefore, no longer recommended. Despite these occurrences the author concluded that “IV regional anaesthesia is associated with a low incidence of complications and can therefore be considered a safe anaesthetic technique.”6
Since these studies have been published, there have been large improvements in safety. This can largely be attributed to the advent of dedicated automatic tourniquet machines, discontinuation of buvipicaine use, and increased scrutiny on how to appropriate dose the anaesthetic.
Challenges associated with the Bier Block
Staff comfort level may be a barrier to the use of the BB despite advantages. Staff, including nurses, cast techs and support staff must be appropriately trained. An interdisciplinary simulation and web-based training course developed to teach the use of BB at tertiary pediatric emergency department showed increase comfort in use of the BB technique and an increase in clinical utilization of 37% in forearm reductions performed in the ED.5
Quality assurance of the equipment including a double-cuff tourniquet is required with frequent testing to ensure appropriate and safe function. At the Montreal Children’s Hospital a nurse is present with the patient at all times, to monitor vitals and adverse events, answer family and patient’s questions adequately and provide a safe and comforting environment for the patients.
Another challenge is that some patients require additional sedation, or they are unable to withstand the tourniquet discomfort. If the proximal cuff is causing the patient discomfort, the distal cuff can be inflated and proximal cuff can then be deflated minimizing discomfort. In 1816 patients aged 4-70 undergoing Bier Block only 5 cases were reported where BB was associated with suboptimal anaesthesia. These cases required sedation such fentanyl/midazolam, hematoma block, IV morphine, oral midazolam and IV procedural sedation.3
The review literature reports that the BB is a safe and effective technique when appropriate patients are selected and there is frequent testing of the equipment and staff are trained adequately (Bretholz, 2016). It would be an appropriate procedure to be considered in the ED However, this appropriate training and comfort with the procedure is likely the rate limiting step at most institutions. The procedure should not be performed without appropriate institutional support, equipment and training.
Reviewing with Staff
The Bier block is a safe, easy, effective and family-centered technique that provides the necessary analgesia for forearm fracture reduction. For those interested in learning more about Bier blocks and our Montreal Children’s Hospital Bier block PED program please download our App on the Apple App store.