[Endocrine stress parameters during TIVA with remifentanil or sufentanil]

Increases of heart rate and blood pressure during anaesthesia are interpreted as a response to surgical stimulation, although the endocrine response and the cardiovascular reaction can differ markedly. We compared remifentanil and sufentanil as part of a TIVA for retinal surgery with respect to the endocrine stress responses and haemodynamic reactions.

After ethics committee approval and informed consent, 22 patients (ASA I-III) scheduled for retinal surgery were included in this patient-blind, randomized, prospective parallel-group study and allocated to one of the two groups receiving TIVA with propofol (4 mg/kg/h) and remifentanil (R-group) 0.25 microgram/kg/min, or sufentanil (S-group) 1 microgram/kg before surgery with dosage adjustments according to haemodynamic parameters. Prolactin, growth hormone, cortisol, epinephrine and norepinephrine were measured 60 min before anaesthesia, 30 min after start of surgery and 30 min after extubation.

(Significance level: P < 0.05) Only prolactin increased significantly in both groups during the surgical procedure, the S-group showing a greater increase than the R-group. Cortisol and norepinephrine concentrations decreased during surgery in both groups significantly. Growth hormone and epinephrine concentrations only decreased in the S-group during operation while there was no significant change in the R-group. The blood pressure dropped by about 30% in both groups intraoperatively while there was a tendency towards lower heart rates in the R-group with 58/min vs. 64/min in the S-group (mean).

The increase of prolactin concentrations could be interpreted as a result of the stimulation of mu 1-receptors. As all other measured stress hormones did not increase in both groups, remifentanil and sufentanil both provide an effective suppression of noxious stimulation induced endocrine response.