Remifentanil preventing hemodynamic changes during laparoscopic adrenalectomy for pheochromocytoma.

In this prospective case-series study, a balanced anesthetic scheme of sevoflurane in nitrous oxide supplemented with remifentanil and sustained neuromuscular block was applied in nine patients scheduled for laparoscopic adrenalectomy for pheochromocytoma. Laparoscopic adrenalectomy to treat pheochromocytoma results in marked catecholamine release during pneumoperitoneum and tumor manipulation. Remifentanil infusion was adjusted to maintain systolic arterial pressure between 120-170 mmHg. Increased infusion rate of remifentanil was used (up to 3 microg/kg/min) to prevent and treat marked hemodynamic changes from catecholamine release during tumor manipulation. Hpotension after tumor removal was treated with additional colloids fluids and decreasing the remifentanil infusion rate by 25-50%.

Ketamine-induced changes in metabolic and endocrine parameters of normal and 2-kidney 1-clip rats.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the effect of ketamine on the endocrine and lipid metabolic status of the renal-banded animals. METHODS: Forty male rats were randomly divided into four groups. Group A served as control, Group B animals received ketamine intraperitoneally at a dose of 100 mg kg(-1), Group C was submitted to 2-kidney 1-clip experimental hypertension and Group D received ketamine as above, as well as being submitted to renal artery clipping. Atrial natriuretic peptide, angiotensin II and free fatty acid concentrations were measured in serum. In addition, adipose tissue lipoprotein lipase activity and angiotensin II content were determined, while the left ventricular weight relative to body weight was used as a cardiac hypertrophy index. RESULTS: In renal-banded rats (Groups C and D) serum atrial natriuretic peptide, free fatty acid and angiotensin II concentrations as well as ventricular weight were increased, while adipose tissue lipoprotein lipase activity was lower than in control animals (Groups A and B). Ketamine administration did not influence angiotensin II concentrations either in normal (Group B) or banded rats (Group D). Ketamine increased serum atrial natriuretic peptide and free fatty acid concentrations only in normal animals (Group B). It had no influence on adipose tissue lipoprotein lipase activity either in normal (Group B) or banded animals (Group D). Adipose angiotensin II content did not differ between the four groups. CONCLUSION: Ketamine increased the atrial natriuretic peptide and free fatty acid concentration in normal rats. In 2-kidney 1-clip animals, ketamine did not elicit an additional response of serum atrial natriuretic peptide or free fatty acids levels. Its contribution to these factors was not significant.

Mechanisms of ketamine action on lipid metabolism in rats.

BACKGROUND AND OBJECTIVE: This study was conducted to determine the effect of ketamine on metabolic homoeostasis and particularly in lipoprotein lipase (LPL) activity in adipose tissue. METHODS: Sixty male Wistar rats were divided into six groups of 10 each. Group A served as controls, while Groups B-F received, respectively, ketamine 60, 80, 100, 120 and 140 mg kg(-1) intraperitoneally. The animals were sacrificed 20 min after the administration of ketamine. Insulin concentrations in plasma and total cholesterol, triglyceride, high-density lipoprotein (HDL) and free fatty acid (FFA) concentrations in serum were measured. LPL activity in adipose tissue and medium-chain acyl-CoA dehydrogenase (MCAD) content in muscle were determined. RESULTS: FFA concentrations in serum significantly increased from the second lowest dose of ketamine. Insulin concentrations in plasma did not exhibit any significant difference between groups. MCAD levels were 0.5-fold more in Group F than in Group A, while there were no significant differences between control group and Groups B-E. Furthermore, high concentrations (120 and 140 mg kg(-1)) of ketamine interfered with in metabolic homoeostasis by significantly reducing LPL activity, thus elevating triglyceride concentrations in serum without affecting cholesterol and HDL metabolism. CONCLUSIONS: Ketamine induces various metabolic effects due to changes in adipose LPL activity and MCAD levels in muscles. These findings seem to be significant only at high doses.