[Hemodynamic effects of the induction of general anesthesia after low thoracic epidural anesthesia]. / Effets hémodynamiques de l'induction d'une anesthésie générale après installation d'une péridurale thoracique basse.

Sixteen ASA 1 or 2 patients scheduled for abdominal surgery were included in the study after they had given their informed consent. Thirty minutes after starting a low-thoracic epidural anaesthesia (median level of sensitivity loss: T5), the patients were randomly given an intravenous bolus injection of either thiopentone (4 mg.kg-1, n = 8) or etomidate (0.5 mg.-1, n = 8), associated with succinylcholine 1 mg.kg-1. One minute after induction of general anaesthesia, the patients were intubated and mechanically ventilated (V(T) 8 ml.kg-1, rate 12 c.min-1). Mean arterial blood pressure (MAP) (oscillometric method), cardiac output (CO) (transthoracic bioimpedance) and heart rate were recorded semi-continuously. Total peripheral resistances (TPR) were calculated using the formula TPR = (MA/CO)*80. There were no differences between the groups in patient age, height, weight, and cardiovascular consequences of epidural anaesthesia. After anaesthetic induction and before endotracheal intubation, there was a slight decrease in CO in both groups, without any change in MAP. After intubation, MAP increased in both groups through peripheral vasoconstriction, whereas CO did not increase further. A significant tachycardia was occurred only seen in the thiopentone group, before and after tracheal intubation. This study showed that thiopentone and etomidate were suitable drugs for anaesthetic induction in a patient under epidural blockade. However, the absence of tachycardia following etomidate may be beneficial in cardiac patients. The monitoring of cardiac output determinants during thiopentone and etomidate anaesthesia require further invasive investigations.

[Comparison between conventional and continuous spinal anesthesia using bupivacaine]. / Comparaison entre rachianesthésie conventionnelle et rachianesthésie continue utilisant la bupivacaïne.

A study was carried out to find out whether dividing the dose of local anaesthetic would give a better control of the spread and duration of sensory blockade due to spinal anaesthesia. It was carried out in 34 patients (mean age 62 years) scheduled for elective limb vascular surgery. All were classed ASA 2 or 3. Sensory blockade was assessed using a fine needle, and the degree of motor blockade with Bromage's scale. This was carried out every 5 min for the first 30 min, and thereafter, every 15 min until recovery from anaesthesia was complete. In the first group of patients (n = 16), spinal anaesthesia was obtained with a 26 gauge needle, the patient lying on his side; 4 ml of 0.5% bupivacaine were injected (1 ml every 10 seconds) before putting the patient supine. In the second group (n = 18), the catheter for continuous spinal anaesthesia was set up with the patient in the same position as for the first group. Once a length of 1 cm had been introduced in the subarachnoid space, the patient was placed supine and 2 ml of 0.5% bupivacaine were injected. If 15 min later sensory blockade did not reach T10, further 0.5 ml aliquots were given every 10 min so as to obtain a level of sensory blockade between T9 and T11. Maximum extension of sensory blockade was 15.1 +/- 2.3 metamers in group 1, with an extension to T3 in 2 patients. In group 2, 12.9 +/- 3.1 mg bupivacaine anaesthetized 14.2 +/- 1.9 metamers.(ABSTRACT TRUNCATED AT 250 WORDS)