The use of ketamine in ECT anaesthesia: A systematic review and critical commentary on efficacy, cognitive, safety and seizure outcomes.

OBJECTIVES: This review will discuss ECT efficacy and cognitive outcomes when using ketamine as an ECT anaesthetic compared to other anaesthetics, taking into account important moderator variables that have often not been considered to date. It will also include information on safety and other ECT outcomes (seizure threshold and quality).

METHODS: A systematic search through MEDLINE, PubMed, PsychINFO, Cochrane Databases and reference lists from retrieved articles was performed. Search terms were: "ketamine" and "Electroconvulsive Therapy", from 1995 to September 2016. Meta-analyses, randomised controlled trials, open-label and retrospective studies published in English of depressed samples receiving ECT with ketamine anaesthesia were included (n = 24).

RESULTS: Studies were heterogeneous in the clinical populations included and ECT treatment and anaesthetic methods. Frequently, studies did not report on ECT factors (i.e., pulse-width, treatment schedule). Findings regarding efficacy were mixed. Tolerance from repeated use may explain why several studies found that ketamine enhanced efficacy early in the ECT course but not at the end. The majority of studies did not comprehensively examine cognition and adverse effects were not systematically studied. Only a minority of the studies reported on seizure threshold and expression.

CONCLUSIONS: The routine use of ketamine anaesthesia for ECT in clinical settings cannot yet be recommended based on published data. Larger randomised controlled trials, taking into account moderator variables, specifically reporting on ECT parameters and systematically assessing outcomes are encouraged.