A Comparison of Lithium Dilution Cardiac Output Measurements Made using Central and Antecubital Venous Injection of Lithium Chloride

Abstract

Objective.We have previously described an indicator dilutiontechnique of measuring cardiac output in which lithium chloride is injectedas a bolus via a central venous catheter and cardiac output derived from thearterial lithium dilution curve recorded from a lithium-selective electrode,which we have developed for this purpose. It would be an advantage if thelithium could be injected via the basilic vein (in the antecubital fossa) inthose patients who do not need central venous catheterisation for otherreasons. We have therefore compared cardiac output measurements made usingthese two routes of lithium chloride administration. Methods.Lithiumdilution cardiac output was measured 10 times in each of 10 patients,injecting the lithium chloride alternately via the basilic or central venouscatheter. Results.The mean difference was 0.8 ± 5.2% (SD)(range −8.5 to +7.0%) over a range of cardiac output of 4.5–13l/min. Conclusions.Injection of lithium chloride via the basilic veinin the antecubital fossa allows accurate lithium dilution cardiac outputmeasurements to be made in patients who do not have central venous cathetersin place.