Systemic Absorption of Lidocaine After Hematoma Block
Study Details
Study Description
Brief Summary
This study will measure in children how much numbing medicine, lidocaine, is absorbed into the bloodstream after it is injected into a blood clot (hematoma) around a forearm fracture for pain control when the broken bone is moved back into place (fracture reduction). This is called a hematoma block and is commonly used in the Emergency Unit. To help with anxiety and to add additional pain control, nitrous oxide (laughing gas) is given while the lidocaine hematoma block is placed and continued during the fracture reduction. Advantages of using this technique for pain control instead of an intravenous anesthetic such as ketamine include faster recovery and discharge home, and longer pain control.
Of concern, if too much lidocaine is absorbed into the bloodstream, seizures and irregular heart beating may occur. Bloodstream concentrations of lidocaine after a hematoma block have been measured in only one study of 8 adults and found to be at significant but safe levels. No study has been published in children to measure bloodstream lidocaine levels when a hematoma block is used. Because children's bones are still growing and more metabolically active than adult bones, the investigators believe it is important to determine whether lidocaine blood levels in children are also at safe levels when using a standard lidocaine hematoma block for reduction of fractures. The investigators also want to determine whether bloodstream lidocaine levels correlate with type of fracture, size of the fracture hematoma and effectiveness of pain control during fracture reduction.
The investigators also aim to determine if there is a difference in absorption pattern between different types of distal radius fractures, if there is a correlation between fracture type and systemic lidocaine absorption, if there this a correlation between fracture type and fracture hematoma size, and if there is a correlation between fracture type and ability to provide adequate pain and sedation control with lidocaine hematoma block/inhaled nitrous combination. The investigators believe blood lidocaine levels after hematoma block in children will peak at safe levels, but will be higher than those observed in adults. They believe that a more displaced fracture will have a larger hematoma, that a larger hematoma will be associated with a higher peak blood lidocaine level, and that a higher peak blood lidocaine level will be associated with more successful pain control scores and satisfaction with the procedure.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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Phase 4 |
Detailed Description
When a subject with an eligible distal forearm fracture is identified, the subject will be approached for enrollment and consent. Fracture hematoma size will then be estimated using bedside ultrasound operated by trained pediatric emergency faculty or fellows. Ultrasound measurement of the dimensions of the fracture hematomas will be performed at the subject's bedside in the Emergency Department by pediatric emergency physicians trained in ultrasound use and in the specific methods for fracture hematoma size measurement. Obtaining the measurements of hematoma size will be performed by a standard protocol: The fractured bone will be scanned longitudinally on the dorsal-lateral surface to obtain the largest measurement of the length and depth of the associated fracture hematoma. Transverse scan will be obtained on the dorsal-lateral surface to determine width at the largest measurement. These measurements will then be used to calculate the total volume of the hematoma. If no dorsal hematoma is noted, an attempt at identifying volar hematoma may be made and its presence noted.
50% nitrous oxide/50% oxygen then will be administered to the subject by face mask for a minimum of 2 minutes before venous catheter insertion (50% nitrous oxide will continue to be administered until fracture reduction is completed). Nitrous oxide currently is administered regularly in the St. Louis Children's Emergency Department for painful procedures including fracture reduction, abscess incision and drainage, laceration repair and venous catheter placement. Nitrous oxide 50% blended with 50% oxygen will be administered for this study by credentialed emergency unit staff using a continuous flow delivery system that includes scavenging of exhaled nitrous oxide. Standard monitoring for deep sedation will be used as described in the clinical protocol.
A venous catheter then will be inserted into the uninjured arm. A lidocaine hematoma block will be injected by an orthopedic surgery resident using 2.5 mg/kg, maximum of 100mg, of 1% buffered lidocaine. The recommended lidocaine dose for hematoma block in children is 3-5 mg/kg. However, in a previous study, in another pediatric trial, and in the single report of plasma lidocaine levels in adults, 2.5 mg/kg of 1% lidocaine based upon the patient's weight, maximum 100 mg, was found effective and without adverse effects.
The Pediatric Sedation State Scale will be administered by the sedation provider, and a research assistant when available, and used for subsequent analysis to quantify subjects' responses to the injection of the hematoma block and fracture reduction. This scale has been validated for procedural sedation. Pediatric Sedation State Scale scores will be determined before nitrous oxide is begun (baseline), as the hematoma block is placed, at 60 second intervals during reduction and moulding, and 15 minutes after moulding is completed. The PSSS during each interval will be averaged when multiple time points are available.
Serial blood samples will be drawn through the indwelling venous catheter by a nurse or medic at 5, 10, 20, 40 and 60 minutes after injection of the hematoma block. Serial plasma lidocaine levels will be measured as follows. 5 mL samples of blood will be obtained via the indwelling venous catheter at 5, 10, 20, 40 and 60 minutes after injection of the lidocaine hematoma block. The samples of blood will be collected in standard red top vacutainer blood tubes and processed, frozen and stored in the SLCH/BJC Lab.
At 5 minutes after the hematoma block injection, the orthopedic surgeon will attempt fracture reduction. If the subject has minimal response to squeezing the fracture site prior to 5 minutes post injection, reduction may begin at that time. Nitrous oxide administration will be stopped and administration of 100% oxygen will begin when the orthopedic surgeon indicates satisfactory fracture reduction as determined by bedside fluoroscopy (standard procedure), a cast or splint has been applied, and, if necessary, the cast has been split. Oxygen administration will be stopped when the subject's exhaled nitrous oxide concentration falls below 10% or the subject pulls the nitrous oxide mask off the face.
If the subject resists the fracture reduction or verbally indicates significant pain, ketamine sedation will be administered via the indwelling venous catheter and fracture reduction completed under deep sedation. Post procedure pain score via the Wong-Baker Faces scale, and post procedure surveys will be administered 15 minutes after nitrous administration is stopped. After the subject's recovery from sedation, the subject, subject's parents/guardians, physician providing sedation (inhaled nitrous) and the orthopedic surgeon will be asked to rate their satisfaction with the sedation and analgesia for the fracture reduction using a Likert scale ranging from 1 (not satisfied at all) to 10 (very satisfied). Recovery from sedation satisfactory for discharge home is indicated by a score of 10 on the Modified Aldrete Scale below, and the child can sit up unaided along with control of pain and vomiting. Family will be contacted via telephone 48 hours after their visit to assess for any late adverse effects.
Adverse events will be documented on a data collection sheet using consensus-based definitions that include the event, time and any intervention employed. In addition, the subject will be asked about symptoms typically seen with procedural sedation and lidocaine toxicity including: vomiting, nausea, tinnitus, circumoral or tongue numbness, metallic taste in mouth, nystagmus, vision changes, muscle twitching, tremors, seizure, respiratory depression, chest pain, difficulty breathing, palpitations, ECG changes on monitor (type noted, ECG strip printed), and any other unpleasant or euphoric symptom.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Lidocaine Hematoma Block
|
Drug: Lidocaine 1% Injectable Solution
The lidocaine will be injected into the fracture hematoma using buffered 1% lidocaine solution at a dose of 2.5 mg/kg (0.25 mL/kg), maximum dose 100 mg (10 mL). Using a 30-gauge needle to minimize pain, a small skin wheal of lidocaine will be injected over the fracture site. A 21-gauge needle will then be attached to the lidocaine filled syringe and passed through the skin wheal used to inject the lidocaine into the fracture hematoma. To confirm the needle is in the fracture hematoma, a small amount of blood from the hematoma will be aspirated into the syringe filled with lidocaine before injecting the lidocaine, as in standard practice.
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Outcome Measures
Primary Outcome Measures
- Plasma Lidocaine Levels [Serial plasma lidocaine levels will be measured during a single subject's distal forearm fracture reduction, to be measured over the course of 60 minutes form the injection of lidocaine into the hematoma block.]
Measured concentrations of plasma lidocaine levels for subjects undergoing lidocaine hematoma block for their distal radius fracture reduction.
Secondary Outcome Measures
- Pediatric Sedation State Scale Scores [This will be assessed every 60 seconds throughout the process of reduction and splinting of the subject's fracture. The scale ranges from a score of 0 to 5, with 0-1 and 4-5 being undesirable, 2-3 being desirable (appropriately sedated).]
Measurement of patient overall comfort (in terms of sedation) will be assessed by an observer using the Pediatric Sedation State Scale scoring system during the reduction of the subjects fracture.
Other Outcome Measures
- Satisfaction scores [This will be obtained immediately after procedure is complete, and will be a Likert scale from 0-10 where 0 is not satisfied at all and 10 is very satisfied.]
Satisfaction with the procedure and level of provided analgesia and sedation will be assessed from the parent, subject, sedationist and orthopedist.
Eligibility Criteria
Criteria
Inclusion Criteria:
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ASA status class 1 or 2
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Ages 5-17
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Parent/guardian is present
Exclusion Criteria:
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Open fracture
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Previous attempt at reduction
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Multiple other injuries
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Physeal (growth plate) fractures
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Volar displacement of the distal fracture fragment
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Delayed presentation (>48 hrs from injury)
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Concern for significant neurovascular injury
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Refracture through a healing fracture
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History of adverse effect from lidocaine or nitrous oxide
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Active psychosis
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Non English speaking parents
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Liver disease
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Cardiac disease
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Abnormal bones such as osteogenesis imperfecta or osteopenia from lack of use
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Developmental abnormalities
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Saint Louis Children's Hospital | Saint Louis | Missouri | United States | 63110 |
Sponsors and Collaborators
- Washington University School of Medicine
Investigators
None specified.Study Documents (Full-Text)
None provided.More Information
Publications
- Bear DM, Friel NA, Lupo CL, Pitetti R, Ward WT. Hematoma block versus sedation for the reduction of distal radius fractures in children. J Hand Surg Am. 2015 Jan;40(1):57-61. doi: 10.1016/j.jhsa.2014.08.039. Epub 2014 Oct 11.
- Blasier RD. Anesthetic considerations for fracture management in the outpatient setting. J Pediatr Orthop. 2004 Nov-Dec;24(6):742-6.
- Coté CJ, Wilson S. Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures. Pediatr Dent. 2019 Jul 15;41(4):26E-52E.
- Cravero JP, Askins N, Sriswasdi P, Tsze DS, Zurakowski D, Sinnott S. Validation of the Pediatric Sedation State Scale. Pediatrics. 2017 May;139(5). pii: e20162897. doi: 10.1542/peds.2016-2897.
- Kennedy RM, Porter FL, Miller JP, Jaffe DM. Comparison of fentanyl/midazolam with ketamine/midazolam for pediatric orthopedic emergencies. Pediatrics. 1998 Oct;102(4 Pt 1):956-63.
- Luhmann JD, Schootman M, Luhmann SJ, Kennedy RM. A randomized comparison of nitrous oxide plus hematoma block versus ketamine plus midazolam for emergency department forearm fracture reduction in children. Pediatrics. 2006 Oct;118(4):e1078-86. Epub 2006 Sep 11.
- Meinig RP, Quick A, Lobmeyer L. Plasma lidocaine levels following hematoma block for distal radius fractures. J Orthop Trauma. 1989;3(3):187-91.
- Naranje SM, Erali RA, Warner WC Jr, Sawyer JR, Kelly DM. Epidemiology of Pediatric Fractures Presenting to Emergency Departments in the United States. J Pediatr Orthop. 2016 Jun;36(4):e45-8. doi: 10.1097/BPO.0000000000000595.
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