[Isobaric 2% lidocaine in continuous subarachnoid anesthesia using microcatheters]

The objective in the study of the clinical effect of isobaric 2% lidocaine for continuous spinal anesthesia with a microcatheter technique. Nine consecutive patients undergoing lower abdominal surgery under spinal anesthesia were enrolled. We inserted 27 G catheters through 22 G Sprotte (Intralong) needles to administer 20 mg of isobaric 2% lidocaine followed by successive doses of 10 mg until the required level of anesthesia was reached. Repeated injections of 10 mg were given during surgery whenever the level of anesthesia fell as much as one metamere, possibly permitting pain to appear. We recorded hemodynamic variables, level of anesthesia and motor block, as well as complications during and after surgery. The technique was used with nine patients, for whom the mean presurgical dose was 32.3 +/- 9.2 mg and the mean total dose was 51.3 +/- 25.3 mg. However, the protocol for administering the local anesthetic was suspended in three patients due to difficulty in maintaining the achieved level of anesthesia, as repeated injections were required, with consequent patient discomfort. In these patients relatively high levels of blockade were required and surgery lasted longer than one hour. The protocol followed with isobaric 2% lidocaine was not effective for continuous spinal anesthesia with microcatheters because of difficulty of maintaining level of anesthesia.