randomized study. The patients were divided into two groups 8 mL of 0.5% bupivacaine and 2 mL of 2% lidocaine, in group 1 (n 10) were administered for left stellat ganglion blockade, using anterior paratracheal approach. After development of Horner syndrome in the same group, we started to measure parameters. Blood flow velocity in bilateral common carotid (CCA) and middle cerebral arteries (MCA) were measured simultaneously before and 20 minutes after SGB, using TCD. At the same time hemodynamic parameters were recorded. Statistical analysis: Mann-Whitney U test, Wilcoxon test, Friedman to directional variance analysis. Results and Discussions: There were no hemodynamic changes in two groups, during the study. In group 1, on the side of SGB, blood flow velocity in CCA significantly decreased (p 0.01) whereas velocity in middle cerebral artery was unchanged. On the contralateral side of to the SGB, significant changes were not observed in blood flow velocity in CCA and MCA. Conclusion: These results suggests that CCA blood flow increases in the blocked side following SGB, with no effect on MCA blood flow. Reference: Nithara K, Dan K. Reg Anesth Pain Med 1998; 23(6): 600–4.

BACKGROUND:Acceptance of a lower transfusion trigger in the perioperative period requires study of the effects of anesthetic depth on the tolerance to acute isovolemic anemia. Anesthetic agents with negative effects on the cardiovascular system may exert proportionately greater depressant effects on cardiac output response than on tissue oxygen demand, reducing tolerance to acute isovolemic anemia. METHODS:In the first study, animals were anesthetized with halothane (n = 14; 23.8 +/- 4.8 kg, mean +/- SD). In a second study, animals were anesthetized with ketamine (n = 14; 24.3 +/- 4.7 kg). In each study, dogs were randomly allocated to receive either low or high concentrations of anesthetic. Oxygen delivery and oxygen consumption were determined from independent measurements during a stepwise isovolemic hemodilution protocol. In each dog, critical oxygen delivery was determined from a plot of oxygen consumption versus oxygen delivery using a least-sum-of-squares technique. Critical hemoglobin (hemoglobin) was determined from a plot of hemoglobin versus oxygen consumption using the same method. RESULTS:With both agents, the higher anesthetic concentration was associated with decreased oxygen consumption, resulting in a lower critical oxygen delivery. However, critical hemoglobin was significantly higher in the animals receiving the higher anesthetic dosage (1.5 vs. 1.0 minimum alveolar concentration of halothane: 4.1 +/- 1.3 vs. 2.3 +/- 0.5 g/dl, P < 0.05; high- vs. low-dose ketamine: 3.7 +/- 1.4 vs. 2.5 +/- 0.6 g/dl, P < 0.05). This was related to a marked blunting of the cardiac output response to hemodilution in the animals receiving the higher anesthetic dosage. CONCLUSIONS:Increased anesthetic depth with halothane or ketamine resulted in a decreased tolerance to acute anemia, as reflected by a significant increase in critical hemoglobin concentration.

The Department of Anesthesiology and Reanimation is organised in units with clinical activities, which include the pre-operative care of patients, anesthesiological care and immediate post-operative supervision. Two post-operative treatment rooms also form part of the department. The main fields of research of the various units result from collaborations with other departments of Hôpital Erasme, in particular with regard to the development of advanced techniques or fit within the confines of the speciality.

We have explored systemic and regional tolerance to haemodilution during anaesthesia with two different synthetic colloids. Eighteen dogs undergoing mechanical ventilation during anaesthesia with ketamine were submitted to progressive normovolaemic haemodilution with either gelatin (GEL; n = 9) or hydroxyethylstarch (HES; n = 9) administered on a 1:1 ratio. Systemic oxygen delivery was calculated from measurement of thermodilution cardiac output and arterial oxygen content, while systemic oxygen consumption was determined from expired gas analysis. Mesenteric oxygen delivery and consumption were determined using ultrasonic flow measurements, and arterial and mesenteric venous oxygen contents. The critical haemoglobin concentration (i.e. the haemoglobin value below which oxygen consumption becomes oxygen delivery dependent) was mean 3.6 (SD 0.8) g dl-1 in the GEL and 3.5 (1.5) g dl-1 in the HES group. The mesenteric critical oxygen extraction ratio (O2ER) (GEL 50.1 (12.1)%; HES 48.5 (13.4)%) was significant lower than the systemic critical O2ER (GEL 66.1 (8.4)%; HES 67.7 (7.1)%). There were no significant differences between the GEL and HES groups for any of these variables, or in the amount of colloid administered. During the study, oxygen delivery decreased almost linearly with reduction in haemoglobin, indicating a lack of cardiac output response to anaemia during ketamine anaesthesia.