Bier's Block Versus Mini-bier's Block in Patients Undergoing Hand Surgery

Study Overview
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Brief Summary
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By means of an observer-blinded, randomized controlled trial, the analgesic efficacy of an upper-arm Bier's block and a forearm mini-Bier's block will be investigated in patients undergoing hand surgery. The hypothesis is that there is no difference between the two types of anesthetic techniques with respect to the analgesic efficacy.

Detailed Description
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Introduction: Several ways of anesthesia can be used to perform hand surgery, being general anesthesia, intravenous regional anesthesia as well as locoregional anesthesia. Locoregional anesthesia and intravenous regional anesthesia are often performed since patients can be discharged from the hospital more rapidly. A conventional Bier's block is performed using a tourniquet on the upper arm to create a bloodless field and to contain the anesthetics within the surgical area (1). Complications are rare but are often linked to a systemic toxicity reaction after releasing the tourniquet (2). A mini-Bier's block in which the tourniquet is placed on the fore-arm, has been shown to be a safe and effective way of anesthesia to perform hand surgery. By using this type of anesthesia, the dose of the anesthetic can be reduced compared to a conventional Bier's block which reduces the risk of systemic toxicity reactions (3-5). Currently, studies that made a comparison between the two anesthesia techniques are scarce and inconsistent. Next to that, those studies also used different types of anesthetics and dosages. To see which technique is advantageous in clinical practice, the investigators want to investigate the efficacy of the Bier's block and mini-Bier's block in patients that are planned to undergo hand surgery. Outcome measures: The primary aim of this study is to compare the analgesic efficacy of the Bier's block versus the mini-Bier's block. The hypothesis is that there is no difference between the two techniques. A blinded surgeon will determine the analgesic efficacy of these techniques (graded as complete or incomplete) and divide the efficacy in 4 grades. Grade 1 and grade 2 are considered complete blockade, while grade 3 and grade 4 are considered incomplete blockade. Grade 1: complete motor and sensory blockade, grade 2: partial motor blockade but no pain or deep pressure sensitivity, grade 3: partial motor blockade with mild pain requiring rescue local or opioid analgesia, grade 4: incomplete motor- and sensory blockade requiring sedation/conversion to general anesthesia). Secondary study outcomes: Onset time, which is defined as the time from the injection of the local anesthetic until the complete sensory loss in hand (assessed by the blinded surgeon via pin prick). Patient's pre-, intra- and post-operative pain scores will be measured via an 11-point Numeric Rating Scale (NRS) in which number 0 means no pain at all, number 5 means moderate pain and number 10 means worst possible pain. Tourniquet time: the amount of time that the tourniquet is inflated. Tourniquet tolerance time: the amount of time required for the inflated tourniquet to cause a painful sensation (NRS > 3). Satisfaction with the surgical field (bloodless field) will be graded by a blinded surgeon, measured using a 5-point scale (1= extremely dissatisfied until 5= extremely satisfied). The time spent in the operating room. Duration of surgery. General patient satisfaction will be assessed using a 7-point Likert Scale, in which number 1 equals extremely dissatisfied and number 7 means extremely satisfied. Design: In this monocentric, investigator-initiated, observer-blinded, prospective, randomized, controlled, non-inferiority trial, 2 anaesthetic procedures will be compared in patients that undergo hand surgery (Carpal Tunnel Syndrome, trigger finger, dequervain tenovaginitis, disease of Dupuytren, ganglion cyst). This study will be performed according to the Declaration of Helsinki and will be approved by the ethics committee of the JESSA Hospital, Hasselt, Belgium before the start of the study. A written informed consent will be obtained before participation in the study. Randomization will be performed using a computer-generated random allocation sequence. Allocation numbers will be sealed in opaque envelopes, which will be opened in sequence by an independent anesthesiologist who is not involved in the assessment of outcomes. Both the surgeon and the researcher will be blinded for the used type of anesthesia. Since the clear difference between an upper arm and forearm tourniquet, all patients will receive a second tourniquet which will not be inflated. That is, patients receiving the Bier's block will receive an additional forearm tourniquet which will not be inflated and patients in group of the mini-Bier's block will receive an additional upperarm tourniquet which will not be inflated. In this way, a possible de-blinding of the surgeon and researcher is minimized. Study Procedures: The patient will first receive information about this study. Before the start of the study, written informed consent will be obtained, after which the patient will be randomized to one of the 2 treatment groups. Before surgery, all patients will receive an intravenous catheter in the contralateral arm with infusion of 0.9% Natriumchloride (NaCl), paracetamol 1g and standard monitoring (non-invasive blood pressure, electrocardiogram and O2 saturation measurements). In the Bier's block group: An intravenous catheter will be placed in the dorsal vein of the hand that will undergo surgery. Afterwards, a tourniquet will be placed on the upper arm and inflated, after which the anesthetic can be administered via the dorsal vein catheter (40ml Lidocaine 0.5%). The tourniquet remains inflated for 25 minutes to reduce systemic toxicity reactions postoperatively. In the mini-Bier's block group: An intravenous catheter will be placed in the dorsal vein of the hand that will undergo surgery. Afterwards, a tourniquet will be placed on the forearm and inflated, after which the anesthetic can be administered via the dorsal vein catheter (25ml lidocaine 0.5%). The tourniquet remains inflated for 10 minutes to reduce systemic toxicity reactions postoperatively. Before the start of the surgery, the blinded surgeon will assess the quality of the block (primary outcome) using a forceps. The quality of the block will be graded complete or incomplete as described above. In case of grade 1 or grade 2, the surgical procedure can start. In case of grade 3, the blockade will be enhanced (local anesthetic or intravenous opioid administration (alfentanil or sufentanil)). In case of grade 4, sedation/conversion to general anesthesia will be performed. All secondary outcome measures will be investigated by the blinded researcher. Statistical analysis: Sample size was determined for the primary study outcome with the aim to reject the non-inferiority of the mini-Bier's block. Based on a meta-analysis (unpublished data) we expect a 98.5% complete blockade in the experimental group (mini-Bier's block) and a 100% complete blockade in the control group (Bier's block). With a difference of 5% between the 2 groups and a binary outcome (complete/incomplete), we calculated that 135 patients are needed per group (α=0.05, power=0.80). Considering a drop-out rate of 3.5%, the total number of patients is 140 per group. Descriptive statistics will be presented as frequencies and percentages of the total amount of patients for categorical variables, while numerical variables will be presented as mean. Group comparison will be performed using Chi-square test (or a Fisher's Exact test when necessary) for frequencies. Depending on normality, a Mann-Whitney U test or a Student's t-test will be used. Corrections will be applied for multiple measurements of the Numerical Rating Scale (NRS) for pain scores. An average difference of 1.3 points or more on the NRS pain score is considered clinical relevant. A p-value <0.05 is considered statistical significant, while p<0.10 is considered a tendency.

Official Title
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A Randomized Controlled Trial to Investigate the Efficacy of a Bier's Block Compared to a Mini-bier's Block in Patients Undergoing Hand Surgery

Conditions
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Surgery, Anesthesia, Local

Intervention / Treatment
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* Procedure: mini-Bier's block with lidocaine 0.5% 25ml
* Procedure: Conventional Bier's block with lidocaine 0.5% 40ml


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males and females ≥ 18 years of age American Society of Anesthesiology (ASA) physical status classification: 1-3 Patients planned to undergo hand surgery which can be performed using either a Bier's block or a mini-Bier's block Exclusion Criteria: < 18 years old Patients that participate in other clinical, pharmaceutical trials or trials with medical devices Patients that previously have been randomized in this trial Patients that need to undergo surgery using sedation/general anesthesia Bilateral surgery BMI ≥ 40 kg/m2 History of neurological conditions Chronic pain symptoms Concomitant use of Opioids in the last month Diabetes mellitus with organ damage Oversensitivity to local anesthetics Blood clotting disorders Inability to understand and adhere to the study design

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Bier's block<br>Upperarm intravenous regional anesthesia (Bier's block) with lidocaine 0.5% 40ml | Procedure: Conventional Bier's block with lidocaine 0.5% 40ml<br>* An intravenous catheter will be placed in the dorsal vein of the hand that will undergo surgery. Afterwards, a tourniquet will be placed on the upper arm and inflated, after which the anesthetic can be administered via the dorsal vein catheter (40ml Lidocaine 0.5%). The tourniquet remains inflated for 25 minutes to reduce systemic toxicity reactions postoperatively.<br>* Other names: Upperarm intravenous regional anesthesia (IVRA);|
| Experimental: Mini-Bier's block<br>Forearm intravenous regional anesthesia (mini-Bier's block) with lidocaine 0.5% 25ml | Procedure: mini-Bier's block with lidocaine 0.5% 25ml<br>* An intravenous catheter will be placed in the dorsal vein of the hand that will undergo surgery. Afterwards, a tourniquet will be placed on the forearm and inflated, after which the anesthetic can be administered via the dorsal vein catheter (25ml lidocaine 0.5%). The tourniquet remains inflated for 10 minutes to reduce systemic toxicity reactions postoperatively.<br>* Other names: forearm intravenous regional anesthesia (IVRA);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory and motor block of the hand | This study wants to evaluate and compare the analgesic efficacy of the Bier's block with the mini-Bier's block. The blinded surgeon will assess the analgesic effectivity and grade it as either complete (grade 1 and grade 2) or incomplete (grade 3 and grade 4). Grade 1 is defined as complete motor and sensory blockade; grade 2 is defined as partial motor blockade with no pain or deep pressure sensitivity. Grade 3 is defined as partial motor blockade with mild pain and the need for rescue local or opioid analgesia. Grade 4 is defined as incomplete motor and sensory blockade requiring sedation/conversion to general anesthesia. | 5 minutes after injection of lidocaine 0.5% | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pre-operative pain score: Numeric Rating Scale (NRS) | Pain score before the start of anesthesia technique (measured via an 11-point Numeric Rating Scale where 0 = no pain and 10 is worst pain imaginable) | Before the start of anesthesia technique | 
| Pain due to anesthesia technique: Numeric Rating Scale (NRS) | Pain caused by performing the anesthesia technique (measured via an 11-point Numeric Rating Scale where 0 = no pain and 10 is worst pain imaginable) | At the end of performing the anesthesia technique | 
| Tourniquet time | Total time the tourniquet is inflated | From start of inflation until deflation of the tourniquet | 
| Onset time of analgesia | Onset time of analgesia (starts at injection of the anaesthetic and will continue until complete blockade of the sensory nerves (assessed via pin prick)). When after 10 minutes no sensory blockade occurred, rescue medication (alfentanil (0,5 mg)) will be applied. When alfentanil (0,5 mg) will not provide enough sensory blockade, sedation with diprivan (titration per 1cc) or, if required, conversion to general anesthesia will be applied. | At injection of the anaesthetic until complete blockade of the sensory nerves | 
| Tourniquet tolerance time | Time required for the tourniquet to cause a painful sensation (NRS > 3) | From start of inflation until deflation of the tourniquet | 
| Pain score at start of surgery (surgical incision): Numeric Rating Scale (NRS) | Pain score at surgical incision (start of surgical procedure) (11-point Numeric Rating Scale where 0 = no pain and 10 is worst pain imaginable) | At the start of the surgical procedure | 
| Satisfaction with surgical conditions (bloodless field) assessed by the surgeon with a 5-point likert scale | Satisfaction with surgical conditions (bloodless field): assessed by the surgeon with a 5-point scale. This scale is ranged (1, 2, 3, 4, 5) in which 1 stands for completely dissatisfied and 5 for completely satisfied. | At the start of the surgical procedure | 
| Intraoperative pain score: Numeric Rating Scale (NRS) | Pain score (11-point Numeric Rating Scale where 0 = no pain and 10 is worst pain imaginable) at every 5 min during the surgical procedure (both surgical pain and tourniquet pain) | every 5 min during the surgical procedure | 
| Time in operating room | Time the patient is in operating room (start by entering the operating room until leaving the operating room) | From entering the operating room until leaving the operating room | 
| Time of surgical procedure | Time of surgical procedure (start at surgical incision until closing of the surgical wound) | From start of surgical incision until closing of the surgical wound | 
| General satisfaction of the patient: Likert scale | General satisfaction of the patient with the anesthesia technique (measured via a 7-point Likert scale, with 1 being completely dissatisfied and 7 being completely satisfied) | Assessed on day 1 post surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anesthesia, Bier's block, Mini-Bier's block, Hand surgery