[Local anesthetics in the aqueous humor in local anesthesia of the eye]. / Lokalanaesthetika im Kammerwasser bei örtlicher Betäubung am Auge.

Local anesthetics injected retrobulbarly are detectable in the aqueous humor. From 40 patients who received a total dose of 140 mg lidocaine, 15 mg bupivacaine, and 30 mg etidocaine, samples of aqueous humor were taken between 30 and 90 minutes after administration (average 57 minutes). The mean lidocaine concentration was 1.02 micrograms/ml, that of bupivacaine 0.075 micrograms/ml. Etidocaine, used only for facial nerve block in front of the ear, could not be detected in the aqueous humor. All three substances were found in the central venous blood. It therefore appears unlikely that any of them are transported via the blood-aqueous barrier, whether actively or passively. Local anesthetics can inhibit corneal cell proliferation and result in lens opacification when administered into the conjunctival sac. It may be that local anesthetics detected in the aqueous humor have similar effects resulting from contact with the cornea and lens.

[Catheter brachial plexus anesthesia for intra- and postoperative pain control. Plasma concentrations and analgesia interval in the use of bupivacaine]. / Die Katheter-Plexusanaesthesie des Armes zur intra- und postoperativen Schmerzausschaltung. Plasmakonzentrationen und Analgesie-Intervalle bei der Anwendung von Bupivacain.

In 15 orthopedic patients, undergoing plastic surgery of the upper extremity (elbow, forearm, hand) we studied plasma levels and pain free intervals, when performing catheter axillary plexus block with 0.5% and 0.25% bupivacaine as postoperative analgetic agent respectively. 30 minutes after injection of 40 ml of 0.5% bupivacaine maximum plasma levels were reached (means = 1.46 micrograms/ml), followed by a constant but slow decrease to 1 microgram/ml approximately after 2 h. 11.5 h (mean) after brachial plexus block there was a need for reinjection of local anesthetic solution for postoperative pain control. The pain free interval after 30 ml of 0.25% bupivacaine lasted 10.5 hours on the average. The 'top-up-dose' of 75 mg approximately equal to 30 ml of 0.25% bupicavaine caused only a small rise in plasma levels up to 0.6 micrograms/ml. Catheter brachial plexus block with bupivacaine is an appropriate procedure for both intra- and postoperative pain relief, especially in re-implantation surgery of the upper limb.