Empirical ratio of the combined use of S-ketamine and propofol in electroconvulsive therapy and its impact on seizure quality.

Electroconvulsive therapy (ECT) is an effective treatment for depressive disorders. In certain cases, ECT-associated anaesthesia can be improved by the use of ketofol (i.e., S-ketamine + propofol). We aimed to evaluate the empirical mixing ratio of ketofol in these cases for better clinical implementation. We retrospectively investigated n = 52 patients who received 919 ECT sessions with S-ketamine plus propofol as anaesthetic agents. Several anaesthesia and ECT-related parameters including doses of S-ketamine and propofol were analysed. The mean empirically determined S-ketamine/propofol ratio was 1.38 (SD ± 0.57) for 919 individual ECT sessions and 1.52 (SD ± 0.62) for 52 patients, respectively. The mean relative dose was 0.72 (± 0.18) mg/kg S-ketamine and 0.54 (± 0.21) mg/kg propofol. Higher propofol dose was associated with poorer seizure quality. Seizure quality and time in recovery room were significantly influenced by age. Ketofol could be an option to exploit the advantageous qualities of S-ketamine and propofol, if both doses are reduced compared with single use of S-ketamine or propofol. Patients with poor seizure quality may benefit from lower propofol doses, which are applicable by the addition of ketamine. An empirically determined mixing ratio in favour of ketamine turned out to be preferable in a clinical setting. Recovery time was primarily prolonged by higher age rather than by ketamine dose, which had previously often been associated with a prolonged monitoring time in the recovery room. These new findings could improve electroconvulsive therapy and should be replicated in a prospective manner.

Dexmedetomidine for the management of postictal agitation after electroconvulsive therapy with S-ketamine anesthesia.

OBJECTIVES: Postictal agitation (PIA) represents one of the most common complications during a modified electroconvulsive therapy (ECT) course. Its clinical management can be challenging especially in cases with poor response to benzodiazepines. Dexmedetomidine, a highly selective alpha-2 adrenoceptor agonist acting predominantly in the locus coeruleus, exerts sedative effects without causing relevant respiratory depression. To the best of our knowledge, this is the first study that aimed to assess the impact of dexmedetomidine use with S-ketamine anesthesia on PIA reduction in ECT. PATIENTS AND METHODS: We retrospectively analyzed 7 patients who underwent 178 ECT sessions with S-ketamine anesthesia between June 2011 and July 2015 at the Central Institute of Mental Health Mannheim. In 101 sessions, the patients received dexmedetomidine in combination with S-ketamine anesthesia. The decision for dexmedetomidine use was based on individual clinical presentation (patients with positive PIA history). A multivariate repeated measurement logistic regression analysis was conducted to investigate the effect of dexmedetomidine use on the occurrence of PIA. We hypothesized that the use of dexmedetomidine reduced the incidence of PIA also in combination with S-ketamine anesthesia. RESULTS: The prevalence of PIA in ECT sessions with dexmedetomidine administration was lower (mean per patient, 34% vs 62%). In the multivariate logistic regression analysis, the use of dexmedetomidine predicted the non-occurrence of PIA in a highly significant manner (P=0.001, z=-3.83, odds ratio =0.011-0.303). CONCLUSION: Adjunctive use of dexmedetomidine to S-ketamine anesthesia in ECT seems to be a promising tool for the management of intractable PIA syndrome.