Passive leg raising test versus rapid fluid challenge in critically ill medical patients

The passive leg raising (PLR) test is a simple test to detect preload responsiveness. However, variable fluid doses and infusion times were used in studies evaluating the effect of PLR. Studies showed that the effect of fluid challenge on hemodynamics dissipates in 10 min. This prospective study aimed to compare PLR and a rapid fluid challenge (RFC) with a 300-ml bolus infused within 5 min in adult patients with a hemodynamic compromise.

Critically ill medical patients with signs of systemic hypoperfusion were included if volume expansion was considered. Hemodynamic status was assessed with continuous measurements of cardiac output (CO), when possible, and mean arterial pressure (MAP) at baseline, during PLR, and after RFC.

A total of 124 patients with a median age of 65.0 years were included. Their acute physiology and chronic health evaluation (APACHE) II score was 19.7 ± 6.0, with a sequential organ failure assessment (SOFA) score of 9.0 ± 4.4. Sepsis was diagnosed in 73.3%, and 79.8% of the patients were already receiving a norepinephrine infusion. Invasive MAP monitoring was established in all patients, while continuous CO recording was possible in 42 patients (33.9%). Based on CO changes, compared with those with RFC, the false positive and false negative rates with PLR were 21.7 and 36.8%, respectively, with positive and negative predictive values of 70.6 and 72.0%, respectively. Based on MAP changes, compared with those with RFC, the false positive and false negative rates with PLR compared to RFC were 38.2% and 43.3%, respectively, with positive and negative predictive values of 64.4 and 54.0%, respectively.

This study demonstrated a moderate agreement between PLR and RFC in hemodynamically compromised medical patients, which should be considered when testing preload responsiveness.