(1525) Stability of Fluid Responsiveness During Usual Care: Dynamic Stroke Volume Guided Resuscitation

Introduction: Fluid challenges (FC) are used to evaluate if a patient will experience augmented stroke volume (SV) in response to IV fluid during resuscitation for undifferentiated shock. However, there is limited evidence regarding the stability of fluid responsiveness (FR) over time when multiple fluid challenges are administered. Hypothesis: We hypothesize that the fluid responsiveness of patients presenting with undifferentiated shock, as assessed by the change in SV (SV) in response to repeated FC, may vary over time.

Methods: Prospective registry of patients presenting with undifferentiated shock to 5 hospitals who were managed with the Baxter Starling SV cardiac output monitor as a component of usual care shock resuscitation. Fluid challenges (FC, 250-500mL crystalloid bolus) were administered rapidly and %SV for each sequential FC, the primary outcome, was recorded.

Results: 692 patients at 5 sites (57-332 patients/site), 52.1% female median age 67 (IQR: 56 to 75), median body surface area 1.92 (IQR: 1.7 to 2.1) were evaluated for FR (SV>10%) in response to up to 4 FC. 431 patients (62.4%) were FR to first FC (FC1) and 166 (75.1%) of those remained responsive to a subsequent FC2. Overall median SV to FC1 was 14.42% (IQR: 6.2% to 25.2%). Amongst FR patients median SV for FC1 was 21.3% (IQR: 15.6% to 34.0%). On the other hand, 261 (37.6%) patients were not FR: SV 3.78% (IQR: -0.32% to 6.95%). Similarly, for FC2 (n 221, 75.1% FR), FC3 (n 86, 74.4% FR), and FC4 (n 36, 86.1% FR), median SV for FR patients was 14.38% (IQR: 7.04% to 25.56%), 14.59% (IQR: 4.04% to 25.68%), and 16.91% (IQR: 5.48% to 27.85%) respectively. The median SV (n) for patients not FR to FC2, FC3, and FC4 were 8.95% (IQR: 4.6% to 19.47%), 5.62% (IQR: 1.67% to 22.07%), and 15.57% (IQR: 2.04% to 21.13%) respectively. A positive FR at the first FC was associated with a positive response to a second challenge (accounting for 7% of the variance FC2 (adjusted R2=6.42, P = 0.0006). However, a negative response to the first FC was not associated with subsequent fluid responsiveness.

Conclusions: FR to a first FC is common during shock resuscitation and persistence of FR is predicted by initial FR state FR to FC1 may have utility in guiding continued resuscitation, particularly by identifying patients who are likely to remain FR.