[Morphine metabolism in critical patients with need-directed peridural morphine infusion for the management of postoperative pain].

For constant analgesia after abdominal surgery, 34 patients (Group I) and 14 patients under intensive care (Group II) received epidural morphine infusions at mean hourly rates of 0.23 +/- 0.04 mg morphine in the first hour to 0.01 +/- 0.0 mg in the 50th hour, and 1.55 +/- 0.26 mg in the first hour to 0.20 +/- 0.08 mg in the 50th hour, respectively, after an initial bolus injection of 2 mg morphine. Whereas in Group I metabolized morphine immunoreactivity reached a plateau within 20 minutes which lasted until 8 p.m. on the operation day, in Group II a far higher plateau (p less than 0.001) was attained,--but only after some hours--which lasted until 8 p.m. on the first postoperative day. In the course of the treatment, concentrations of metabolized morphine immunoreactivity in serum and in urine decreased in both groups.