[Anesthetic technics for surgery in otoneurology].

A description is given of a technique named "Protected Sleep", which produces a deep and residual analgesia and neurolepsia, without interfering with spontaneous respiration. A deep, stable and reliable neuroanesthesia is achieved by means of a partial pharmacodynamic blockage of the neuro-humoral reaction system. It is recognisable by the following features: 1 degree a smooth transition through pre-, per- and post-operative stages, avoiding in particular immediate awakening; 2 degrees a relative arterial hypotension, low venous pressure good peripheral circulation and tissular perfusion; 3 degrees light hypothermia; 4 degrees completely spontaneous respiration. This last factor is, to our way of thinking, of great importance: The venous return remains physiologically unchanged during inspiration in the peroperative as well as in the pre- and postoperative phases, enabling the maintenance of a constant, low venous pressure. Furthermore, should danger exist, the preservation of spontaneous respiration facilitates the immediate control of the respiratory centre. In this way we can obtain: 1. An almost perfect bloodless surgical field with good conditions for dissecting. 2. A low cerebro-spinal fluid pressure. 3. Decreased brain volume. 4. Absence of postoperative haemorrage. 5. Little of no postoperative oedema. 6. Little or no postoperative hyperthermia. "Protected sleep" is a pharmacodynamic technique realised mainly through administration of a combined and sufficient dose of pethidine, N-allyl-normorphine and levome promazine. For induction, a given dose of diazepam is combined with a single dose of succinyl-choline, to facilitate intubation, followed by a large dose of the narco-neuro-leptanalgesic mixture. For maintenance, nitrous oxide, oxygen, methoxyflurane and additional doses of the mentioned mixture are administered. Undirectional gas flow, without rebreathing, is provided, using the Ruben valve. In this paper on neuroanaesthesia, the technique of "Protected Sleep" and the pre-, per- and postoperative management and positioning of the neurosurgical patient are described in detail.