Trial Information

Comparison of Periosteal and Subcutaneous Infusions of Articaine and Bupivacaine in Treatment of Acute Pain After Sternotomy

Acute pain after open heart surgery can be moderate or strong and is mostly caused by
sternotomy. Pain is the worst during the first two post-operative days and, if not
adequately treated, can delay the patient´s recovery from surgery. Sternotomy pain can be
alleviated by using paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs) and
opioids. All these drugs may have remarkable side-effects which may delay the recovery from
surgery: opioids are respiratory depressants and slower the gastrointestinal motility,
NSAIDs reduce intrarenal blood flow and may disturb coagulation. Post-operative opioid
consumption can be reduced by using wound infiltration analgesia.

The use of wound infiltration analgesia has not been extensively investigated in treatment
of acute pain after sternotomy. There is some evidence, that 0.5% bupivacaine reduces the
acute post-sternotomy pain when infused constantly via catheters placed under the fascia
(periosteal placement) and the skin.

During 48 hours infusion toxic bupivacaine plasma levels were not observed. There is an
evidence that local anesthetics can be bacteriostatic both in vitro and in vivo.

Articaine is an amide-type local anesthetics, which has been used extensively in dental
procedures since more than forty years. It has been successfully used in infiltration,
epidural, spinal and other regional anesthesia procedures. Articaine is quickly hydrolyzed
in plasma and excreted by kidneys. Clearance of articain (500-1110l/h) is faster than that
of lidocaine (68l/h) and it is also the reason for articaine´s low toxicity profile. Because
of it´s low toxicity and high ability to penetrate the periosteal tissue, articaine may be
advantageous in treatment of acute pain after sternotomy, but aforementioned indication for
use of articaine has not been investigated. Compared to other local anesthetics, articaine
in high concentration has the same neurotoxicity profile, when injected directly into rat´s
sciatic nerve. Articaine has not been extensively compared to other local anesthetics, but
according the latest odontologic investigation, single dose 0.5% bupivacaine and single-dose
4% articaine were comparable in their analgesic effects during tooth extraction procedure.
There are no controlled randomized trials comparing analgesic effect of articaine and other
local anesthetics infusions.

In our investigation bupivacain 0.5 % was chosen as an active control, because it has
appeared effective in acute postoperative pain and it has reduced the need for opioid
analgetics after sternotomy