Stress hormones during the wake-up test in scoliosis surgery.

STUDY OBJECTIVE

To compare hemodynamic and endocrine stress responses of two anesthetic regimes during intraoperative wake-up tests in scoliosis surgery.

DESIGN

Randomized, controlled clinical study.

SETTING

University hospital.

PATIENTS

40 ASA physical status I and II teenage patients scheduled for scoliosis surgery.

INTERVENTION

Patients were randomly divided into two groups: the propofol group (Group P) and the sevoflurane group (Group S). In Group P, anesthesia was induced with propofol and remifentanil and was maintained with infusions. Sevoflurane and remifentanil were used in Group S. After surgical instrumentation, patients were awakened, and the wake-up times were recorded. To determine the stress responses, blood samples were taken before induction, 10 minutes after surgical incision, before the wake-up test, during the wake-up test, and 10 minutes after the wake-up test. Cortisol, epinephrine, and norepinephrine concentrations, and hemodynamics all were recorded at the same time.

MEASUREMENTS AND MAIN RESULTS

The times from discontinuation of anesthetics to eye opening and movement were similar in both groups. Epinephrine and norepinephrine concentrations during the wake-up test were significantly higher than pretest results in both groups (p < 0.001). There were no statistically significant differences between groups in heart rate or blood pressure.

CONCLUSIONS

Propofol-remifentanil anesthesia is equivalent to sevoflurane-remifentanil anesthesia for a wake-up test. Both the propofol- and sevoflurane-based anesthetic regimens abolish hemodynamic and endocrine stress responses to incision for scoliosis surgery in teenagers. Intraoperative wake-up testing is associated with substantial catecholamine stress despite virtually unchanged mean arterial pressure and heart rate.