Anaesthetic depth control using closed loop anaesthesia delivery system vs. target controlled infusion in patients with moderate to severe left ventricular systolic dysfunction.

OBJECTIVES: To compare the efficacy of anaesthetic depth control using Closed Loop Anaesthesia Delivery System (CLADS) and Target Controlled Infusion (TCI) in patients with moderate to severe left ventricular dysfunction (LVSD).

DESIGN: Randomized control trial.

PATIENTS: Forty ASA III/IV adult patients with moderate to severe LVSD scheduled for open heart surgery.

INTERVENTIONS: Propofol was administered using CLADS or TCI for maintaining BIS of 50. Induction and maintenance doses were controlled automatically in CLADS. Dixon's up and down method was used to estimate the plasma concentration needed for induction in TCI.

MEASUREMENT: Percentage of total anaesthesia time ("valid CLADS time") for which BIS remained within ±10 of target (BIS=50).

MAIN RESULTS: BIS remained within ±10 of the target for a significantly longer duration of time in CLADS group (p=0.001). Performance parameters like Median Performance Error (MDPE), p=0.024; Median Absolute Performance Error (MDAPE), p=0.0212; and global score p=0.017 were significantly better in CLADS group. Total propofol consumption was significantly less in CLADS group (p=0.014). Mean value (95% CI) of EC50 and EC95 for target plasma propofol concentration for induction was 1.62 (1.45-1.79) μgml-1 and 1.87 (1.73-2.96) μgml-1 respectively using probit analysis.

CONCLUSIONS: Closed loop delivery of propofol using CLADS performed significantly better than TCI in this subset of patients. CLINICAL TRIALS REGISTRATION NO.: www.ClinicalTrials.gov-NCT02645994.