Page 250 Acute Pain Management

The overall incidence of long‐term injury following brachial plexus block ranged between
0.02% and 0.4% depending on the definition of injury and length of follow‐up (Borgeat et al,
2001 Level IV; Klein et al, 2002 Level IV; Neal et al, 2002 Level IV; Watts & Sharma, 2007 Level IV).
Borgeat et al studied continuous popliteal nerve blockade in 1001 patients with no incidence
of neuropathy (Borgeat et al, 2006 Level IV) while Compere et al (Compere, Rey et al, 2009 Level IV)
reported an infection incidence a 0.5% risk of severe neuropathy — 2 patients of the 400
included in the study.
Ultrasound guidance has been shown to reduce the likelihood of intravascular injection
(RR 0.16; 95% CI 0.05 to 0.47; P<0.001) but insufficient data are available to determine
whether neurological injury is less likely (Abrahams et al, 2009 Level I). A review of 1010
consecutive peripheral nerve blocks performed under ultrasound guidance concluded that the
incidence of neurological symptoms, most thought to be due to causes others than the block,
was similar to that reported for blocks performed using traditional techniques (Fredrickson &
Kilfoyle, 2009 Level IV).
Permanent neurological injury has been reported following injection of local anaesthetic into
the cervical spinal cord when an interscalene block was performed under general anaesthesia
(Benumof, 2000).
Toxicity
Local anaesthetic toxicity due to accidental intravascular injection or rapid absorption is a
known complication of all peripheral nerve blocks, and was associated with cardiac arrest
(1.4 per 10 000) or seizures (7.5 per 10 000) in a prospective survey of over 21 000 cases
(Auroy et al, 1997 Level IV). The incidence of acute systemic toxicity reported by ARAC was
0.98:1000 procedures (Barrington et al, 2009 Level IV). Surveys specifically investigating brachial
plexus blocks have reported a higher rate of seizures (0.2%) (Brown et al, 1995 Level IV; Borgeat
et al, 2001 Level IV) (see Section 5.1.3).
CHAPTER 7 Infection

Despite a structured literature search regarding infection in regional analgesia, insufficient
prospective trials were found to conduct a meta‐analysis (Schulz‐Stubner et al, 2008). In a follow‐
up of 1416 patients with CPNB catheters only one patient had a serious complication (psoas
abscess), although a relatively high rate of catheter colonisation (28.7%) occurred (Capdevila
et al, 2005 Level IV). Unfortunately, the infection control practices were not fully disclosed. In
another series, 16% of all CPNB catheters were colonised and the risk factors for colonisation
were catheter placement in the groin and repeated changes of the catheter dressing (Morin,
Kerwat et al, 2005 Level IV). In perineural catheters that were tunnelled, the rate of
contamination was just 6% (Compere, Legrand et al, 2009 Level IV).
After 48 hours, 57% of femoral nerve catheters were colonised (Cuvillon et al, 2001 Level IV).
Wiege et al (Wiegel et al, 2007 Level IV) documented an incidence of local inflammation at the
catheter site (0.6%) and local infection (0.2%) in femoral and sciatic blocks. The incidence of
local inflammation and infection in a study of 2285 patients with CPNB (axillary, interscalene,
psoas compartment, femoral, sciatic and popliteal) was 4.2% and 3.2% respectively (Neuburger
et al, 2007 Level IV). Borgeat et al studied continuous popliteal nerve blockade in 1001 patients
with no incidence of infection (Borgeat et al, 2006 Level IV) while Compere et al reported an
infection incidence of 0.25% — 1 patient of the 400 included in the study — for the same block
(Compere, Rey et al, 2009 Level IV).
The strongest recommendations for preventive measures are hand hygiene and effective skin
preparation, preferably with alcohol‐based chlorhexidine solution — as found in the epic2
National Guidelines in the United Kingdom (Pratt et al, 2007). These guidelines recommend full

202 Acute Pain Management: Scientific Evidence