Alterations of acid-base- and electrolyte status immediately following electroconvulsive therapy

Electroconvulsive therapy (ECT) is an established treatment for severe affective and psychotic disorders. However, there are only few studies on metabolic short-term changes, for example in acid-base balance and electrolyte concentrations after ECT. In this study, serial venous blood gas analysis was utilized to systematically record alterations in these parameters and evaluate them in relation to safety-relevant aspects. Blood samples were obtained via a peripheral intravenous catheter immediately, and then 5, 15, 30, and 60 min after ECT in patients requiring either first or repeat ECT. Blood-gas analyses were performed to monitor concentrations of electrolytes and acid-base status among others. A repeated measures analysis of variance was applied to test for longitudinal changes of blood gas parameters. 47 ECT sessions were included in the final data analysis (19 patients, mean age 54.4 ± 12.7 years, 12 females). Following ECT, there were significant changes in electrolytes and acid-base parameters. The most significant effects were observed in the acid-base status, where there was decline in pH (reference range 7.35-7.45) from a mean of 7.39 to 7.29 followed by a recovery to near normal values within one hour (F(3.4;156.4) = 105.5; p < 0.001; n = 47). Except of an increase in calcium, there were no relevant changes in electrolyte levels. This study demonstrates a statistically significant drop of serum pH after ECT based on complementary alterations in lactate and carbon-dioxide levels. Most of these alterations may simply be due to the convulsive exertion of the tourniquet region. However, they are short-lived and return to baseline within one hour confirming the safety of the method with respect to acid-base alterations.Clinical Trial Registration This study was prospectively registered on April 20, 2020 in the German trial register ( https://www.drks.de/drks_web/ ) The trial registration number is DRKS00021467.