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ropivacaine with a ropivacaine/ levobupivacaine potency ratio of 0.98 (95% CI 0.80 to 1.20)
(Polley et al, 2003 Level II).
Epidural local anaesthetics
For postoperative epidural infusions, dose‐ranging studies established that 0.2% ropivacaine
was a suitable concentration (Scott et al, 1995 Level II; Schug et al, 1996 Level II). Therefore, most
investigators compare infusions of bupivacaine or levobupivacaine at 0.1% or 0.125% with
ropivacaine 0.2%, which removes any imbalance in comparative potency.
The majority of studies find similar analgesic outcomes with postoperative epidural infusions
based on these strengths (Jorgensen et al, 2000 Level II; Macias et al, 2002 Level II; Casati, Santorsola
et al, 2003 Level II). Motor block is of clinical relevance in low thoracic or lumbar epidural
infusions and has been reported to be less intense with epidural ropivacaine than with
bupivacaine (Zaric et al, 1996 Level II; Muldoon et al, 1998 Level II; Merson, 2001 Level II). However,
this finding has not been supported by other authors.
Ropivacaine 0.2% and levobupivacaine 0.125% provided similar analgesia with similar adverse
effects and no motor block when infused via thoracic epidural catheters for lung surgery (De
Cosmo et al, 2008 Level II). Patient‐controlled lumbar epidural analgesia for prostatectomy using
ropivacaine 0.2% or levobupivacaine 0.125% resulted in similar pain relief, adverse effects and
incidence of motor block (Heid et al, 2007 Level II). These two local anaesthetics in these
concentrations were also equivalent to 0.125% bupivacaine after hip surgery (Koch et al, 2008
Level II). However, epidural ropivacaine 0.165% was inferior to levobupivacaine 0.125% after
CHAPTER 5 bupivacaine 0.125% and lignocaine 0.5%, the regression of sensory blockade under continuous
orthopaedic surgery (Smet et al, 2008 Level II). In a comparison between ropivacaine 0.2%,
infusion was least with ropivacaine (Kanai et al, 2007 Level II).
The relevance of dose, not concentration or volume of local anaesthetic infused, was
confirmed in two trials. The same dose of a mixture of levobupivacaine in three different
concentrations (0.5%, 0.25%, and 0.15%) and sufentanil administered during continuous
thoracic epidural infusion for thoracotomy resulted in similar efficacy and adverse effects
(Mendola et al, 2009 Level II) as did two concentrations (0.15% and 0.5%) of levobupivacaine in
another trial (Dernedde et al, 2008 Level II).
Neither infusions of bupivacaine 0.125% nor ropivacaine 0.2% interfered with
neurophysiological assessments after scoliosis surgery (Pham Dang et al, 2008 Level II).
At concentrations of 0.5% or greater, there were no significant differences in onset time and
intensity or duration of sensory blockade between bupivacaine, levobupivacaine or
ropivacaine used for epidural analgesia (Cheng et al, 2002 Level II; Casati, Santorsola et al, 2003
Level II)
Local anaesthetic/opioid combinations
The quality of pain relief from low‐dose epidural infusions of plain local anaesthetic
consistently benefits from the addition of adjuvants such as opioids (Crews et al, 1999 Level II;
Scott et al, 1999 Level II; Hubler et al, 2001 Level II; Senard et al, 2002 Level II) or alpha‐2
adrenoceptor agonists (Milligan et al, 2000 Level II; Niemi & Breivik, 2002 Level II) (see Section 5.3).
Potential dose‐sparing benefits are more obvious for local anaesthetic side effects
(hypotension and motor block) than for opioid‐related side effects (Walker et al, 2002 Level I).
Comparisons of patient‐controlled epidural analgesia (PCEA) using ropivacaine 0.2%,
ropivacaine 0.125% and levobupivacaine 0.125%, all with sufentanil 1 mcg/mL (6 ml
background plus 2 ml bolus), showed no differences in pain relief or motor block; patients
given 0.2% ropivacaine used similar volumes, thus receiving more total dose of local
anaesthetic and the same amount of sufentanil (Sitsen et al, 2007 Level II). Similarly, there was

122 Acute Pain Management: Scientific Evidence