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Die Struktur von Avenacosid B wurde durch stufenweisen enzymatischen Abbau, durch Hydrolyse des permethylierten Glykosids und mit Hilfe der Massenspektrometrie bestimmt. Danach hat es den Aufbau eines 3‐O‐{[α‐L‐Rhamnopyranosyl‐(1→4)]‐[〈β‐D‐glucopyranosyl‐(1→3)〉‐β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐glucopyranosyl}‐3β.26‐dihydroxy‐22.25‐epoxy‐(22S: 25S)‐Δ5‐furostene‐26‐β‐D‐glucopyranosid (5).

After anterolateral thoracotomy, before incision closure, indwelling plastic catheters were inserted percutaneously under digital and/or visual control into the intercostal space of access and the two neighbouring ones. Initially, we injected 25 mg of bupivacaine through each catheter (to a total of 75 mg), and subsequently - on the patients demand - another 15 to 25 mg per catheter. To date, 25 patients received repetitive intercostal nerve blocks by this method (ICB-group). We compared their personal and perioperative data with those of another 30 patients, receiving opiates systemically after major thoracic surgery (SA-group). Multiple blood samples from the ICB-group were analyzed by gaschromatography for bupivacaine concentration-time-profiles. In 19 of 25 patients (76%) the bupivacaine-injections provided sufficient analgesia, 6 patients required additional analgesics. The duration of general anaesthesia (ICB: 174 min vs. SA: 136 min) and the operation time (ICB: 103 min vs. SA: 94 min) were not statistically different in both groups. The periods of intensive care therapy (ICB: 0.7 d vs. SA: 1.2 d), artificial respiration (ICB: 11.2 h vs. SA: 21.6 h) and hospital stay (ICB: 12.1 d vs. SA: 14.2 d) were shorter for the ICB-group. Atelectasis (ICB: 20% vs. SA: 37%) and pneumonia (ICB: 0 vs. SA: 13%) were observed less frequently than in the control group, whereas tachyarrhythmia occurred in 6 of 25 ICB-patients compared to 4 of 30 SA-patients. Nevertheless, none of these parameters reached statistical significance (p less than 0.05). Maximum bupivacaine levels of 0.65 +/- 0.21 micrograms/ml were found after 29 +/- 12 min of intercostal application.(ABSTRACT TRUNCATED AT 250 WORDS)

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In a randomised clinical study, two total intravenous anaesthesia techniques for microlaryngoscopic laser surgery were compared. After an induction dose of 100 mg methohexital, Group I received a maintenance infusion of 10 mg·min‐1. In Group II anaesthesia was obtained by 15 mg midazolam followed by 0.1 mg·min‐1 continuously and terminated by the injection of flumazenil. For analgesia 5 mg alfentanil were administered. Opiate‐induced respiratory depression was antagonised by 0.08 to 0.12 mg naloxone. Prior to, during, and after surgery, adrenergic response was assessed by HPLC‐analysis of blood taken from a peripheral vein. Haemodynamic responses to the operation and during the post‐operative period were almost identical in both groups. In Group I, the mean recovery period of 14 min was significantly longer than in Group II (9 min), where patients received a mean dose of 0.53 mg (0.15) flumazenil. Resedation could be observed in all patients receiving flumazenil within 60 min after antagonisation, which was associated with a mean decrease in O2‐saturation from 95% to 88%. There was no difference in epinephrine and norepinephrine blood levels between the two groups prior to and during anaesthesia. In all patients, arousal was associated with a significant increase in the epinephrine plasma concentration. While blood levels in Group I decreased during the post‐operative period to levels prior to surgery, the concentrations in Group II remained elevated. In one patient who received no naloxone, the reversal of midazolam action induced a 16‐fold increase in catecholamine levels (from 50 to 800 ng.1‐1) associated with a tachycardia of 170 b·min‐1 and hypertension of 160 mmHg. It is concluded that both anaesthetic techniques provide appropriate and equivalent anaesthesia for laryngeal surgery under jet ventilation. The shorter post‐operative period of unconsciousness after flumazenil administration can be regarded as an advantage. Yet, in single cases the use of flumazenil may lead to excessive adrenergic reactions combined with tachycardia and hypertension. This has to be considered when the antagonist is administered to high‐risk patients. The higher degree of post‐operative vigilance is less accepted by some patients. Post‐operative observation after antagonisation is mandatory as resedation may result in hypoxic episodes.

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Midazolam, the latest henzodiazepine agonist, may be used in doses of 0.15 to 0.2 mg.kg‐1 for induction of anaesthesia. It provides good correlation between plasma concentration and anaesthetic effect with an interindividual variability of only 20–25%. On this basis, dosage recommendations for midazolam in total intravenous anaesthesia techniques are possible, aiming at hypnotic plasma concentrations of at least 250 ng.ml‐1. Due to its biological half‐life of 150–180 min and interindividual differences in drug susceptibility, prolonged recovery periods have been observed that can safely and reliably be antagonised by flumazenil, if necessary. It is recommended that flumazenil be administered carefully by titration in increments of 0.1 mg.min‐1 to avoid emergence reactions by awakening too fast (tachycardia, hypertension). Usually a mean total dose of 0.4–0.5 mg will lead to prompt awakening.

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