Postoperative pain may be associated with shallow breathing, inability to cough, and reduction in spirometric values which lead to restrictive pattern of ventiltion with hypoxemia and/or hypercapnea. Therfore postoperative pain should be managed
by
using appropriate methods. To investigate the analgesic effect of interpleural block with 0.25% or 0.375% bupivacaine hydrochloride, 30 patients were randomly divided into one of three groups(saline group, 0.25% bupivacaine group and 0.375%
bupivacaine
group). In the saline group, 0.9% saline with 1:200,000 epinephrine(0.5ml/kg) was injected into the pleural cavity via the chest drainage tube, either 0.25% or 0.375% bupivacaine with 1:200,000 epinephrine(0.5ml/kg) was injected with the same
manner of
the saline group in the bupivacaine groups, respectively. Respiratory parameters(minute volume, tidal volume, respiratory rate, forced vital capacity, incentive spirometric volume, cough score, deep inspiratory score), numeric pain rating score
and
hemodynamic changes were measured before anesthetic induction, 10 minutes before the study drug injection, 30 and 60 minutes after the study drug administration, respectively.
Postoperative respiratory parameters were decreased at 10 minutes before the drug injection compared to the preanesthetic values in all groups. There were no statistically significant differences of all parameters after the drug administration
among
three groups. There was a tendency of improvement in the respiratory parameters after the drug injection in saline and 0.25% bupivacaine groups and a greater tendency of improvement of respiratory parameters and numeric pain rating score in
0.375%
bupivacaine group than the other groups. Only one case of tachycardia was developed in the saline group.
These results suggest that the postoperative pain after thoracotomy is not appropriately manged by using the interpleural block with 0.25% or 0.375% bupivacaine hydrochloride(0.5ml/kg) administrated via the drainage tube of the chest.
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