Influence of dextran on the absorption of adrenaline-containing lignocaine solutions: a protective mechanism in local anaesthesia.

The effect of adding 6% dextran to a lignocaine solution containing adrenaline was studied in 27 neurosurgical patients during modified neuroleptanaesthesia. Before trepanation they received infiltration anaesthesia of the scalp at the site of the proposed operation. For a period of 1 h following injection plasma concentrations of adrenaline were measured by high pressure liquid chromatography and serum concentrations of lignocaine by gas chromatography. The addition of dextran caused a significant reduction in the absorption of both adrenaline and lignocaine from the injection site. It is concluded that the dextran adjuvant constitutes a protective mechanism against toxic systemic side effects in local anaesthesia using adrenaline-containing anaesthetic solutions. This effect is particularly significant in patients with pre-existing cardiovascular disease and when local anaesthetic solutions are used in combination with volatile anaesthetics.

Interactions between nimodipine and general anaesthesia--clinical investigations in 124 patients during neurosurgical operations.

Haemodynamic, respiratory, metabolic and endocrine investigations were performed in a total number of 124 patients, divided into four different groups, during opiate anaesthesia for neurosurgical operations in order to characterize general effects of nimodipine, a calcium channel blocking agent with a preferential cerebrovascular action. These studies led to the following conclusions: Nimodipine is a vasodilator drug with a hypotensive action, which is especially obvious in hypertensive patients and in combination with similarly acting agents, such as sodium nitroprusside or nitroglycerin. This vascular hypotensive effect may be also enhanced by combined cardiodepressive activity if nimodipine is applied together with inhaled anaesthetics, such as halothane or isoflurane. Nimodipine as well as other vasodilator drugs may lead to increased pulmonary shunting in patients with artificial ventilation, which, however, can be reduced by adequate positive end-exspiratory pressure. With high doses the decrease of oxygen extraction and consumption, seen with nimodipine, is accompanied by a moderate rise of lactate. Determination of stress hormones did not reveal analgesia potentiation of nimodipine, as has been assumed in other studies.

[Effect of isoflurane and enflurane on somatosensory evoked potentials following stimulation of the median nerve]. / Die Wirkung von Isofluran und Enfluran auf somatosensorisch evozierte Potentiale nach Stimulation des Nervus medianus.

The effects of enflurane and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 25 healthy adult patients. Cervical and cortical SEP were recorded simultaneously. pCO2 and tympanic membrane temperature were kept constant. Following induction of anaesthesia with thiopentone, fentanyl and succinylcholine SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. Isoflurane at inspired concentrations of 0.8, 1.65, 2.5, 3.3% was given to 10 patients at 15 minutes intervals and was reduced after nitrous oxide had been replaced by oxygen. 15 patients received equipotent doses of enflurane (1.1, 2.2, 3.25, 4.3%.) SEP were recorded at the end of each interval. Isoflurane and enflurane caused dose dependent increases in latency of the cortical SEP. This effect was more pronounced with enflurane. Isoflurane reduced amplitude of the primary cortical response more than enflurane, when ventilation was performed with 66.6% nitrous oxide in oxygen. High doses of enflurane in oxygen augmented cortical SEP amplitudes associated with a marked increase in latency. Isoflurance and enflurance anaesthesia slightly altered cervical SEP. Middle latency components of the cortical SEP were progressively diminished with increasing isoflurane or enflurane concentrations. The effect of both agents in terms of delayed latencies and reduced amplitudes should be considered when recordings are performed intraoperatively.

[Measurements of blood supply of freely transplanted rib and iliac crest grafts by the tracer microsphere method]. / Durchblutungsmessungen an frei transplantierten Rippen- und Beckenkammspänen mit der Tracer-microspheres-Methode.

The actual blood perfusion of bone grafts in the lapse of time of their implantation is demonstrable by the tracer microsphere-method. The transplanted rib bone graft turns out to be almost equal to the cortico-spongiose pelvis bone graft concerning the blood perfusion. The long distance bridging rib bone graft shows the blood perfusion of the starting point after six weeks.