Anästhesie, Intensivtherapie, Notfallmedizin
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Anasth Intensivther Notfallmed · Jun 1986
[Protective effect of lidocaine in maintaining the function of peripheral nerves].
The conduction preserving effect of lidocaine was investigated in sheathed vagus nerves of the rabbit. The nerves were preincubated for one hour in solutions containing either 5 (group I, n = 12) or 20 mmol/l glucose (group II, n = 12). ⋯ In contrast, A and C compound action potentials of nerves incubated without lidocaine were extinguished within 69 +/- 5 and 78 +/- 6 minutes, respectively (group I, p less than 0.001) or 106 +/- 9 minutes (group II, p less than 0.005). The results suggest that administration of subblocking concentrations of lidocaine by standard Bier block technique may increase the margin of safety during operations employing a pneumatic tourniquet, especially if the blood flow to the nerves is impaired by vascular diseases or local anaesthetics containing adrenaline.
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Anasth Intensivther Notfallmed · Jun 1986
[Respiratory minute volumes following end expiratory CO2 values in artificial respiration in anesthesia].
During artificial ventilation of anaesthetised patients the respiratory minute volumes were estimated after end tidal CO2-values (eeCO2) and correlated to arterial blood gases. In men the mean respiratory minute volume of 130 ml/kg body weight (b.w.) was significantly above the 113 ml/kg b.w. of women. 9.7-year-old boys and 16-year-old men had higher minute volumes (178 ml/kg b.w. and 148 ml/kg b.w. respectively) in comparison to men of 23 years of age. In contrast, no significant difference was seen in the older age groups. ⋯ EeCO2-values of 3.8 to 4.2 per cent by volume stand for a very marked hyperventilation in the pulmonary healthy patient. The arterial alveolar difference of the CO2 pressure (aADCO2) was in the normal range between 1 and 5 mmHg. The end tidal CO2 estimation is a noninvasive and suitable method to exactly meet the ventilatory needs of the anaesthetised patient.
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Anasth Intensivther Notfallmed · Apr 1986
[Methods of automatic feedback regulation for anesthesia. Concepts and clinical use].
Dosing of drugs used in general anaesthetic practice is largely based on experience and trial-and-error. From the very beginning, anaesthesiological research has always attempted to supply a rational description of the rules governing the dose-response relationship. During the last few decades it became possible to identify pharmacokinetics as a main constituent of the relationship, since the rate of efficacy is primarily governed by the kinetics of the drug and the dose. ⋯ It was shown in all cases that adaptive, model-based feedback control is superior to non-adaptive methods. Pharmacokinetic and/or pharmacodynamic models were successfully applied to the servocontrol of volatile anaesthetics, intravenous hypnotics and neuromuscular blocking agents. Over and above these three applications, directly related to anaesthesia, the impact of feedback control on the regulation of blood pressure and blood glucose is reviewed.
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Anasth Intensivther Notfallmed · Feb 1986
[Changes in water balance and kidney function caused by cardiopulmonary bypass].
The authors studied in 42 patients, 35 normotensives and 7 hypertensives, undergoing open-heart surgery, the perioperative behaviour of renal function and fluid balance. Before cardio-pulmonary bypass (CPB), there was a prerenal impairment of renal function caused by reduced fluid intake. During CPB a marked osmolal diuresis without tubular failure occurred. ⋯ In those hypertensive patients in whom CPB perfusion pressure was below 50 mmHg, the creatinine clearance decreased by 67% during this period. The results indicate that the extent of CPB-induced renal dysfunction is tolerable and does not result in renal failure provided an adequate perfusion pressure is maintained. However, the consequences of marked water retention for undisturbed vital organ function must be taken into consideration.
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480 preclinical cardiopulmonary resuscitations performed at the Emergency Center of the Federal Military Hospital in Hamburg were analysed. The late success was 7.9%, i.e., 38 patients were released after initially successful resuscitation and subsequent clinical treatment. Prognostic parameters indicating late success were deduced from the data. ⋯ Although the prognosis for patients with ventricular fibrillation is better, we are of the opinion that the success rate of preclinical cardiopulmonary resuscitations can be improved by systematic use of antiarrhythmics; metaproterenol sulfate should no longer be administered. The prognosis of resuscitated patients with contracted pupils and gasping breath and of patients with severe tachycardia is relatively good. Cardiac arrest after drowning carries best prognosis: 4 of 7 patients survived.