Variability of anesthetic depth in total intravenous anesthesia vs balanced anesthesia using entropy indices: a randomized, crossover, controlled clinical trial

Abstract

Introduction: Total intravenous anesthesia (TIVA) and balanced anesthesia (BA) are the most commonly used anesthetic techniques. The differences are the variability of the depth of anesthesia between these techniques that might predict which one is safer for patients and presents a lower risk of intraoperative awakening.
 Objective: To determine whether a difference exists in the variability of depth of anesthesia obtained by response entropy (RE). 
 Methods: A crossover clinical trial was conducted on 20 healthy patients receiving upper or lower limb ambulatory orthopedic surgery. Patients were randomly assigned to (a) target-controlled infusion of propofol using the Schnider model at a target concentration of 2.5mg/mL for 15minutes and a 10-minute washout, followed by sevoflurane administration at 0.8 minimal alveolar concentration (MAC) for the reminder of the surgery, or (b) the reverse sequence. Differences in the variability of the depth of anesthesia using RE were evaluated using paired t test.
 Results: The treatment effect showed no significant difference in the average values of RE, during TIVA=97.23 vs BA 97.04 (P=0.39). Carry Over (-4.98 vs 4.08) and Period (100.3 vs 94.68) effects were not significantly different.
 Conclusion: The present study suggests that both anesthetic techniques are equivalent in terms of the stability of the depth of anesthesia. It is important to keep testing the determinants of the efficacy of different populations because the individual behaviors of patients might ultimately tip the scale.