RESUMO
INTRODUCTION: Closed loop total intravenous anesthesia is a technique in which the patient's hemodynamic and anesthetic depth variables are monitored, and based on this information, a computer controls the infusion rate of drugs to keep them within pre-established clinical parameters. OBJECTIVE: To describe the technical and clinical performance of a closed loop system for total intravenous anesthesia with propofol and remifentanil, using the SEDLineTM monitor. DESIGN: Multicentric prospective cohort study. SETTING: Surgery room. PATIENTS: ASA I-II undergoing elective surgery. MEASUREMENTS: The authors designed a closed loop system that implements a control algorithm based on anesthetic depth monitoring and the Patient State Index (PSITM) of the SEDLine monitor for propofol, and on hemodynamic variables for remifentanil. The measurement of clinical performance was made based on the percentage of PSITM maintenance time in the range 20-50. Precision analysis was evaluated by measuring median performance error (MDPE) can be defined as the median difference between actual and desired values, which refers to the degree of precision in which the controller is able to maintain the control variable within the objective set by the anesthesiologist; it represents the direction (over-prediction or under-prediction) of performance error (PE) rather than size of errors, which is represented by MDAPE, median absolute percentage error, Wobble index, which is used for measuring the intrasubject variability in performance error. RESULTS: Data were obtained from 93 patients in three healthcare centers. The percentage of PSITM maintenance time in the 20-50 range was 92% (80.7-97.0). MDPE was 10.7 (- 11.0-18.0), MDAPE 21.0 (14.2-26.8) and wobble 10.7 (7.0-16.9). No adverse surgical or anesthetic events were found. CONCLUSIONS: The closed loop total intravenous anesthesia system with SEDLine developed by the authors was used without major complication and appear to be feasible its use in clinical performance.