Applicability of stroke volume variation in patients of a general intensive care unit: a longitudinal observational study

Sinus rhythm (SR) and controlled mechanical ventilation (CV) are mandatory for the applicability of respiratory changes of the arterial curve such as stroke volume variation (SVV) to predict fluid-responsiveness. Furthermore, several secondary limitations including tidal volumes < 8 mL/kg and SVV-values within the gray zone of 9-13% impair prediction of fluid-responsiveness by SVV. Therefore, we investigated the prevalence of these four conditions in general ICU-patients. This longitudinal observational study analyzed a prospectively maintained haemodynamic database including 4801 transpulmonary thermodilution and pulse contour analysis measurements of 278 patients (APACHE-II 21.0 +/- 7.4). The main underlying diseases were cirrhosis (32%), sepsis (28%), and ARDS (17%). The prevalence of SR and CV was only 19.4% (54/278) in the first measurements (primary endpoint), 18.8% (902/4801) in all measurements and 26.5% (9/34) in measurements with MAP < 65 mmHg and CI < 2.5 L/min/m(2) and vasopressor therapy. In 69.1% (192/278) of the first measurements and in 65.9% (3165/4801) of all measurements the patients had SR but did not have CV. In 1.8% (5/278) of the first measurements and in 2.5% (119/4801) of all measurements the patients had CV but lacked SR. In 9.7% (27/278) of the first measurements and in 12.8% (615/4801) of all measurements the patients did neither have SR nor CV. Only 20 of 278 (7.2%) of the first measurements and 8.2% of all measurements fulfilled both major criteria (CV, SR) and both minor criteria for the applicability of SVV. The applicability of SVV in ICU-patients is limited due to the absence of mandatory criteria during the majority of measurements.