[Quantitative assessment of catecholamine secretion as a rational principle of anesthesia management in...

Fifteen patients with phaeochromocytoma who underwent surgery were studied consecutively.

They received either (10) a balanced anaesthesia technique with isoflurane and fentanyl or (5) a combination of propofol and alfentanil for total intravenous anaesthesia. EEG processing was performed in order to guarantee adequate anaesthetic depth. Antihypertensive therapy was performed with sodium nitropusside. Continuous blood sampling was performed with a roller pump and an autosampler system in order to get high resolution measured of plasma catecholamines. Their concentration was measured by HPLC with electrochemical detection.

There were 100fold differences in the maximal catecholamine concentrations during phaeochromocytoma resection between patients. In some cases adrenaline and noradrenaline levels exceeded normal values by a factor of 1000 to 1500. Secretion rates were calculated on a pharmacokinetic basis an revealed secretion rates of 0.3 to 97.3 micrograms/min for adrenalin and 6.7 und 402.8 micrograms/min for noradrenaline. If systolic blood pressures were greater than 160 mmHg sodium nitroprusside was given by infusion with a rate of 300 +/- 315 micrograms/min. Over a period of 69.2 +/- 39.8 min during resection of the tumor the total dose was 7017 +/- 12433 micrograms.

There were positive correlations between plasma catecholamine concentrations, systolic blood pressure values, and infusion rates of sodium nitroprusside. The comparison of the two anaesthetic techniques resulted in a significant reduction of antihypertensive therapy and more stable haemodynamics in patients with total intravenous anaesthesia. However, the beneficial effect of this anaesthesia regimen has to be proven on a larger basis of patients in a randomized manner.