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Three Part Question

In [children sustaining femoral shaft fracture] is a femoral nerve block using [bupivocaine or a combination of lignocaine and bupivocaine] more effective in producing [onset of analgesia]

Clinical Scenario

An 8-year-old boy presents to the emergency department with an isolated midshaft femoral fracture.
You were previously taught to use a combination of lignocaine and bupivocaine, as the lignocaine would have immediate effect followed by the longer action of bupivocaine.
The anaesthetic registrar disagrees and wants to use bupivocaine alone.

Search Strategy

Medline 1966- Sep 2005 using OVID interface
[( { fracture.mp. OR exp fractures, closed OR exp femoral fractures OR exp fractures OR fracture$.mp} AND { femur.mp. OR exp femur OR femoral. mp.} AND {exp bupivacaine OR exp anesthesia, Local OR exp anesthetics, local OR local anaesthetic.mp. OR exp lidocaine OR lignocaine.mp. OR prilocaine.mp. OR exp prilocaine OR regional anaesthesia.mp.OR nerve block mp. OR exp nerve block OR femoral block.mp. OR femoral nerve block.mp.} LIMIT to human AND English)]

Search Outcome

86 papers found of which 83 irrelevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
McGlone R 1987 uk	27 patients given lignocaine femoral nerve block (FNB) and adrenaline initially then 24 given further bupivocaine0.5% FNB when limb in traction	Observational	Time to onset analgesia.	Lignocaine analgesia achieved average of 8.7 mins (3- 15) Bupivocaine analgesia achieved average of 9.3 mins (3 -21mins)	Proportion of children not stated Small study no statistical analysis Effect of lignociane and bupivocaine compared before and after traction
Denton JS 1988 uk	20 children with femoral shaft fracture given bupivocaine 0.5% FNB	Observational	Time to onset analgesia.	Analgesia achieved in under 10 minutes	No tabulation. Small study No statement of pain measurement
Ronchi L 1989 France	14 children aged 2 to 10 years with mid-shaft femoral fractures given bupivocaine 0.5% FNB	Observational	Time to onset analgesia.	Onset analgesia 8.0 +/ -3.5 min	Small study No statistical analysis

Comment(s)

No study was found using a combination of lignocaine and bupivocaine. All the studies, although of poor quality, seem to agree that bupivocaine acts within 10 minutes. One study, which looked at both drugs in the same cohort of patients, found lignocaine to act only slightly quicker than bupivocaine (no statistical significance calculated) There is little evidence about the potential toxicity of combined local anaesthetic agents. With a relatively short time to onset of action, and well recognised long duration of action, bupivocaine alone would seem the sensible choice.

Clinical Bottom Line

Due to its longer duration of action and relative speed of onset, bupivocaine is adequate as sole local anaesthetic agent for femoral nerve blocks in children with fractured shaft of femur.

References

1. McGlone R. Sadhra K. Hamer DW. Pritty PE Femoral nerve block in the initial management of femoral shaft fractures Archives of Emergency Medicine 4(3): 163-8, 1987 Sep
2. Denton JS. Manning MP Femoral nerve block for femoral shaft fractures in children: brief report Journal of Bone & Joint Surgery – British Volume 70(1): 84, 1988 Jan.
3. Ronchi L. Rosenbaum D. Athouel A. Lemaitre JL. Bermon F. de Villepoix C. Le Normand Y Femoral nerve block in children using bupivocaine Anesthesiology 70(4): 622-4, 1989 Apr.