O. Theissen et al., ANALGESIA AFTER THORACOTOMY USING CONTINUOUS EXTRAPLEURAL BUPIVACAINE, Annales francaises d'anesthesie et de reanimation, 12(3), 1993, pp. 265-272
This study was aimed to assess the efficiency and the side effects of
a continuous administration of bupivacaine into the paravertebral spac
e. Twenty patients, ranked ASA 2 or 3, with a mean age of 57.9 years,
and having had a posterolateral thoracotomy for resection of lung tiss
ue. were randomly assigned to one of two groups, B or C. At the end of
the surgical procedure, a 22 gauge catheter was inserted into the par
avertebral extrapleural space. at T4 levels As soon as pain ocurred du
ring recovery (T0), the patients were given two-hourly intravenous bol
uses of buprenorphine. The patients in group B were also given, throug
h the paravertebral catheter. a 20 ml bolus of 0.25 % bupivacaine, fol
lowed by a continuous steady rate infusion (10 ml - h-1). Group C pati
ents were given normal saline in the same way. All patients could impr
ove their analgesia with 0.05 ml boluses of buprenorphine given by an
auto-analgesia pump (Pharmacia). The following parameters were assesse
d during the 72 h which followed the first injection pain with a visua
l analogic scale, quality of sedation (5 grades), heart and breathing
rate, systolic and diastolic blood pressure, arterial blood gases. In
group B, plasma bupivacaine concentrations were measured throughout th
e infusion, and for an 8-hour period after its end. The statistical an
alysis included 15 patients only, as the catheter had moved into the c
hest cavity in the other 5. Analgesia was qualified to be adequate by
all patients, but there was no statistically significant difference in
the amounts of self-administered buprenorphine between groups B and C
. The buprenorphine concentration reached a plateau of 1.6 mug . ml-1
at about the twelth hour. No signs of toxicity, arterial hypotension o
r respiratory depression were noticed. It was therefore impossible to
conclude that paravertebral bupivacaine was more efficient than normal
saline after thoracotomy for lung surgery. Patient controlled analges
ia used both to achieve an optimal analgesia and to act as an objectiv
e method for assessing analgesia provided less optimistic results than
those previously published by other authors.