Haemodynamic and endocrine responses to induction and intubation with propofol or propofol/sufentanil

W.A.Carvalho¹, P.T.G.Vianna², J.A. Menezes-Filho¹, C.A.C.Oliveira¹.

¹ São Rafael Hospital and Federal University of Bahia, Salvador, Bahia, Brazil, ² Dpto. Anesthesiology, Medical School, UNESP, Botucatu, São Paulo, Brazil.

Background

It has been reported that haemodynamic and endocrine responses occur in response to anesthesia and surgical stress¹. The aim of this study was to evaluate the effects of propofol and propofol/sufentanil on stress responses to anesthetic induction.

Materials and Methods

After obtaining the Hospital ethical committee approval and written informed consent 41 ASA I-II patients, aged 18-60 yr., scheduled for elective surgery under general anesthesia, were randomly assigned in a double-blind manner to receive either propofol infusion alone (Group A) or propofol infusion preceded by venous bolus of 0,5 mg.kg^-1 sufentanil (Group B) or sufentanil 1 mg.kg^-1 (Group C). Anesthesia was induced with propofol administered by a Harvard 22 infusion pump (Harvard Apparatus, USA), controlled by a laptop computer running STANPUMP software (Palo Alto, CA, USA)², programmed to provide the desired target plasma concentration of propofol according to pharmacokinetics parameters reported by Gept. Propofol infusion rate was increased in steps until an adequate target concentration has been achieved to perform satisfactorily tracheal intubation preceded by succinilcholine, 1 mg.kg^-1. At each level, the depth of anesthesia and sedation were assessed by Bispectral Index (BIS) (Aspect Medical Systems, USA) and Ramsay´s sedation scale³. Arterial and venous blood were sampled after intubation for propofol and sufentanil analysis using HPLC with fluorescence detector and CG-MS, respectively. Prolactin, cortisol and glucose levels were measured in venous blood samples before induction and after intubation.

Results and Discussion

Haemodynamic responses to intubation as measured by SBP, DBP, MBP and HR, were significantly higher (p<0,01) in group A than groups B and C during intubation and 2 min. after. The Systolic Blood Pressure (SBP) of group A increased more significantly (p<0,001) during intubation and post-intubation, compared with pre-induction values. There were no statistically significant (p<0,05) effects of propofol and sufentanil on heart rate (HR) and diastolic blood pressure (DBP). Prolactin increased significantly after intubation in the groups A (p<0,002), B (p<0,001) and C (p<0,0002). The glucose levels increased significantly only in group A (p<0,05) after intubation. Even though not statistically significant (p<0,06), the data suggest that there were a decrease in cortisol blood levels in the sufentanil groups. Propofol arterial blood concentrations were significantly higher in group A as well as the target concentration and induction time. In all groups the venous blood concentrations were significantly lower than the arterial blood concentrations (p<0,05). The arterial blood concentrations were closer to the predicted propofol concentrations. As far as BIS is concerned, it was not observed any difference among the groups, the index ranged 51 to 55 during intubation.

Conclusions

Prolactin concentration seems to increase after sufentanil induction while the opioid seems to induces a reduction in cortisol and glucose levels. The data suggest a synergistic association between propofol and sufentanil, which promotes a decrease in induction time, propofol requirements and an attenuation in endocrine responses to anesthesia induction.

References

1. Anesthesiology 81:1384-93,1994.

2. Anesthesiology 83:1194-204,1995.

3. Anesthesiology 84:64-9,1996.